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Sample records for ocean planet popular

  1. Planet Ocean

    NASA Astrophysics Data System (ADS)

    Afonso, Isabel

    2014-05-01

    A more adequate name for Planet Earth could be Planet Ocean, seeing that ocean water covers more than seventy percent of the planet's surface and plays a fundamental role in the survival of almost all living species. Actually, oceans are aqueous solutions of extraordinary importance due to its direct implications in the current living conditions of our planet and its potential role on the continuity of life as well, as long as we know how to respect the limits of its immense but finite capacities. We may therefore state that natural aqueous solutions are excellent contexts for the approach and further understanding of many important chemical concepts, whether they be of chemical equilibrium, acid-base reactions, solubility and oxidation-reduction reactions. The topic of the 2014 edition of GIFT ('Our Changing Planet') will explore some of the recent complex changes of our environment, subjects that have been lately included in Chemistry teaching programs. This is particularly relevant on high school programs, with themes such as 'Earth Atmosphere: radiation, matter and structure', 'From Atmosphere to the Ocean: solutions on Earth and to Earth', 'Spring Waters and Public Water Supply: Water acidity and alkalinity'. These are the subjects that I want to develop on my school project with my pupils. Geographically, our school is located near the sea in a region where a stream flows into the sea. Besides that, our school water comes from a borehole which shows that the quality of the water we use is of significant importance. This project will establish and implement several procedures that, supported by physical and chemical analysis, will monitor the quality of water - not only the water used in our school, but also the surrounding waters (stream and beach water). The samples will be collected in the borehole of the school, in the stream near the school and in the beach of Carcavelos. Several physical-chemical characteristics related to the quality of the water will

  2. The ocean planet.

    PubMed

    Hinrichsen, D

    1998-01-01

    The Blue Planet is 70% water, and all but 3% of it is salt water. Life on earth first evolved in the primordial soup of ancient seas, and though today's seas provide 99% of all living space on the planet, little is known about the world's oceans. However, the fact that the greatest threats to the integrity of our oceans come from land-based activities is becoming clear. Humankind is in the process of annihilating the coastal and ocean ecosystems and the wealth of biodiversity they harbor. Mounting population and development pressures have taken a grim toll on coastal and ocean resources. The trend arising from such growth is the chronic overexploitation of marine resources, whereby rapidly expanding coastal populations and the growth of cities have contributed to a rising tide of pollution in nearly all of the world's seas. This crisis is made worse by government inaction and a frustrating inability to enforce existing coastal and ocean management regulations. Such inability is mainly because concerned areas contain so many different types of regulations and involve so many levels of government, that rational planning and coordination of efforts are rendered impossible. Concerted efforts are needed by national governments and the international community to start preserving the ultimate source of all life on earth.

  3. Ocean Planet. Interdisciplinary Marine Science Activities.

    ERIC Educational Resources Information Center

    Branca, Barbara

    The Ocean Planet is a traveling exhibition from the Smithsonian Institution designed to share with the public what recent research has revealed about the oceans and to encourage ocean conservation. This booklet of lessons and activities adapts several themes from the exhibition for use in middle and high school classrooms. Lesson plans include:…

  4. Visions of our Planet's Atmosphere, Land & Oceans

    NASA Technical Reports Server (NTRS)

    Hasler, Arthur F.

    2002-01-01

    The NASA/NOAA Electronic Theater presents Earth science observations and visualizations in a historical perspective. Fly in from outer space to South Africa, Cape Town and Johannesburg using NASA Terra MODIS data, Landsat data and 1m IKONOS "Spy Satellite" data. Zoom in to any place South Africa using Earth Viewer 3D from Keyhole Inc. and Landsat data at 30 m resolution. Go back to the early weather satellite images from the 1960s and see them contrasted with the latest US and international global satellite weather movies including hurricanes & "tornadoes". See the latest visualizations of spectacular images from NASA/NOAA remote sensing missions like Terra, GOES, TRMM, SeaWiFS, Landsat 7 including 1 - min GOES rapid scan image sequences of Nov 9th 2001 Midwest tornadic thunderstorms and have them explained. See how High-Definition Television (HDTV) is revolutionizing the way we present science to the public. See dust storms and flooding in Africa and smoke plumes from fires in Mexico. See visualizations featured on the covers of Newsweek, TIME, National Geographic, Popular Science & on National & International Network TV. New computer software tools allow us to roam & zoom through massive global images e.g. Landsat tours of the US, and Africa, showing desert and mountain geology as well as seasonal changes in vegetation. See animations of the north and south polar ice packs and with icebergs on the coasts of Greenland and off the coast of Antarctica. Spectacular new visualizations of the global land, atmosphere & oceans are shown. Listen to the pulse of our planet. See how land vegetation, ocean plankton, clouds and temperatures respond to the sun & seasons. See vortexes and currents in the global oceans that bring up the nutrients to feed tiny algae and draw the fish, whales and fisherman. See the how the ocean blooms in response to these currents and El Nino/La Nina climate changes. See the city lights, fishing fleets, gas flares and biomass burning of the Earth

  5. Hydrothermal systems in small ocean planets.

    PubMed

    Vance, Steve; Harnmeijer, Jelte; Kimura, Jun; Hussmann, Hauke; Demartin, Brian; Brown, J Michael

    2007-12-01

    We examine means for driving hydrothermal activity in extraterrestrial oceans on planets and satellites of less than one Earth mass, with implications for sustaining a low level of biological activity over geological timescales. Assuming ocean planets have olivine-dominated lithospheres, a model for cooling-induced thermal cracking shows how variation in planet size and internal thermal energy may drive variation in the dominant type of hydrothermal system-for example, high or low temperature system or chemically driven system. As radiogenic heating diminishes over time, progressive exposure of new rock continues to the current epoch. Where fluid-rock interactions propagate slowly into a deep brittle layer, thermal energy from serpentinization may be the primary cause of hydrothermal activity in small ocean planets. We show that the time-varying hydrostatic head of a tidally forced ice shell may drive hydrothermal fluid flow through the seafloor, which can generate moderate but potentially important heat through viscous interaction with the matrix of porous seafloor rock. Considering all presently known potential ocean planets-Mars, a number of icy satellites, Pluto, and other trans-neptunian objects-and applying Earth-like material properties and cooling rates, we find depths of circulation are more than an order of magnitude greater than in Earth. In Europa and Enceladus, tidal flexing may drive hydrothermal circulation and, in Europa, may generate heat on the same order as present-day radiogenic heat flux at Earth's surface. In all objects, progressive serpentinization generates heat on a globally averaged basis at a fraction of a percent of present-day radiogenic heating and hydrogen is produced at rates between 10(9) and 10(10) molecules cm(2) s(1).

  6. The unstable CO2 feedback cycle on ocean planets

    NASA Astrophysics Data System (ADS)

    Kitzmann, Daniel; Alibert, Yann; Godolt, Mareike; Grenfell, John Lee; Heng, Kevin; Patzer, Beate; Rauer, Heike; Stracke, Barbara; von Paris, Philip

    2015-12-01

    Ocean planets are volatile rich planets, not present in our Solar System, which are dominated by deep, global oceans. Theoretical considerations and planet formation modeling studies suggest that extrasolar ocean planets should be a very common type of planet. One might therefore expect that low-mass ocean planets would be ideal candidates when searching for habitable exoplanets, since water is considered to be an essential requirement for life. However, a very large global ocean can also strongly influence the climate.The high pressure at the oceans bottom results in the formation of high-pressure water ice, separating the planetary crust from the liquid ocean and, thus, also from the atmosphere. In our study we, therefore, focus on the CO2 cycle between the atmosphere and the ocean which determines the atmospheric CO2 content. The atmospheric amount of CO2 is a fundamental quantity for assessing the potential habitability of the planet's surface because of its strong greenhouse effect, which determines the planetary surface temperature to a large degree.In contrast to the stabilising carbonate-silicate cycle regulating the long-term CO2 inventory of the Earth atmosphere, we find that the CO2 cycle on ocean planets is positive and has strong destabilising effects on the planetary climate. By using a chemistry model for oceanic CO2 dissolution and an atmospheric model for exoplanets, we show that the CO2 feedback cycle is severely limiting the potential habitability of ocean planets.

  7. The unstable CO2 feedback cycle on ocean planets

    NASA Astrophysics Data System (ADS)

    Kitzmann, D.; Alibert, Y.; Godolt, M.; Grenfell, J. L.; Heng, K.; Patzer, A. B. C.; Rauer, H.; Stracke, B.; von Paris, P.

    2015-10-01

    Ocean planets are volatile-rich planets, not present in our Solar system, which are thought to be dominated by deep, global oceans. This results in the formation of high-pressure water ice, separating the planetary crust from the liquid ocean and, thus, also from the atmosphere. Therefore, instead of a carbonate-silicate cycle like on the Earth, the atmospheric carbon dioxide concentration is governed by the capability of the ocean to dissolve carbon dioxide (CO2). In our study, we focus on the CO2 cycle between the atmosphere and the ocean which determines the atmospheric CO2 content. The atmospheric amount of CO2 is a fundamental quantity for assessing the potential habitability of the planet's surface because of its strong greenhouse effect, which determines the planetary surface temperature to a large degree. In contrast to the stabilizing carbonate-silicate cycle regulating the long-term CO2 inventory of the Earth atmosphere, we find that the CO2 cycle feedback on ocean planets is negative and has strong destabilizing effects on the planetary climate. By using a chemistry model for oceanic CO2 dissolution and an atmospheric model for exoplanets, we show that the CO2 feedback cycle can severely limit the extension of the habitable zone for ocean planets.

  8. Persistence of oceans on Earth-like planets

    NASA Astrophysics Data System (ADS)

    Schaefer, Laura; Sasselov, Dimitar D.

    2015-01-01

    The habitable zone is an orbital region around a star in which an Earth-like planet can maintain liquid water on its surface given a variety of atmospheric compositions. However, the abundance of water on the Earth's surface is not controlled by the atmosphere, but rather by the deep water/silicate cycle. On the Earth, volcanic outgassing of water from the mantle is balanced by loss of water to the mantle through subduction of water-rich oceanic seafloor. Much of this water is released immediately back to the surface through shallow, water-induced volcanism. However, a small but significant fraction of the water can be transported to deeper levels of the mantle. Mantle convection has therefore played an important role in controlling the size of Earth's surface oceans over the planet's lifetime.The deep water cycle of Earth has been studied with parameterized convection models incorporating a water-dependent viscosity. The abundance of water in the mantle, which lowers the convective viscosity, evolves along with the mantle temperature. Here we present results from a parameterized convection model extended to high pressures to study the deep water cycles of super-Earths. Assuming compositions similar to the Earth, our models indicate that ocean formation will be delayed on 5 MEarth planets by ~1 Gyr after planet formation. Although ocean mass on these planets increases with time, the oceans remain much shallower than for smaller planets, consistent with previous studies. Intermediate mass planets (2-4 MEarth) have immediate, but gradual outgassing and persistent oceans. Small terrestrial planets (≤ 1 MEarth) have rapid initial outgassing, but will gradually lose a significant fraction of their surface oceans due to mantle sequestration over their lifetimes.

  9. DETECTING OCEANS ON EXTRASOLAR PLANETS USING THE GLINT EFFECT

    SciTech Connect

    Robinson, Tyler D.; Meadows, Victoria S.; Crisp, David

    2010-09-20

    Glint, the specular reflection of sunlight off Earth's oceans, may reveal the presence of oceans on an extrasolar planet. As an Earth-like planet nears crescent phases, the size of the ocean glint spot increases relative to the fraction of the illuminated disk, while the reflectivity of this spot increases. Both effects change the planet's visible reflectivity as a function of phase. However, strong forward scattering of radiation by clouds can also produce increases in a planet's reflectivity as it approaches crescent phases, and surface glint can be obscured by Rayleigh scattering and atmospheric absorption. Here, we explore the detectability of glint in the presence of an atmosphere and realistic phase-dependent scattering from oceans and clouds. We use the NASA Astrobiology Institute's Virtual Planetary Laboratory three-dimensional line-by-line, multiple-scattering spectral Earth model to simulate Earth's broadband visible brightness and reflectivity over an orbit. Our validated simulations successfully reproduce phase-dependent Earthshine observations. We find that the glinting Earth can be as much as 100% brighter at crescent phases than simulations that do not include glint, and that the effect is dependent on both orbital inclination and wavelength, where the latter dependence is caused by Rayleigh scattering limiting sensitivity to the surface. We show that this phenomenon may be observable using the James Webb Space Telescope paired with an external occulter.

  10. Applications of Ocean Acoustic Monitoring to Understanding Our Planet

    SciTech Connect

    Tolstoy, Maya

    2005-10-26

    The ocean covers two-thirds of the surface of Earth, and hides long chains of seafloor volcanoes, bizarre and magnificent life forms, and many dynamic geological processes. Shrouded in darkness, much of what happens deep in the ocean is unknown to us. But sound can tell us a great deal about what is going on in the ocean. Changes in the physical properties of seawater with depth allow relatively quiet sounds to travel great distances without loosing much energy. In this way we are able to record many noises that occur within or on the boundary of the ocean, giving us insight into geological, biological and man-made activities in the ocean. One of the most interesting noises to a geophysicist is the sound of mid-ocean ridge volcanic eruptions. These eruptions are forming new surface for our planet and helping create an extraordinary seafloor ecosystem. Examples of sounds heard and some of their implications will be presented.

  11. Mission to Planet Earth. The living ocean: Observing ocean color from space

    NASA Technical Reports Server (NTRS)

    1994-01-01

    Measurements of ocean color are part of NASA's Mission to Planet Earth, which will assess how the global environment is changing. Using the unique perspective available from space, NASA will observe, monitor, and study large-scale environmental processes, focusing on quantifying climate change. NASA will distribute the results of these studies to researchers worldwide to furnish a basis for informed decisions on environmental protection and economic policy. This information packet includes discussion on the reasons for measuring ocean color, the carbon cycle and ocean color, priorities for global climate research, and SeWiFS (sea-viewing wide field-of-view sensor) global ocean color measurements.

  12. Europa, tidally heated oceans, and habitable zones around giant planets

    NASA Technical Reports Server (NTRS)

    Reynolds, Ray T.; Mckay, Christopher P.; Kasting, James F.

    1987-01-01

    Tidal dissipation in the satellites of a giant planet may provide sufficient heating to maintain an environment favorable to life on the satellite surface or just below a thin ice layer. Europa could have a liquid ocean which may occasionally receive sunlight through cracks in the overlying ice shell. In such a case, sufficient solar energy could reach liquid water that organisms similar to those found under Antarctic ice could grow. In other solar systems, larger satellites with more significant heat flow could represent environments that are stable over an order of eons and in which life could perhaps evolve. A zone around a giant planet is defined in which such satellites could exist as a tidally-heated habitable zone. This zone can be compared to the habitable zone which results from heating due to the radiation of a central star. In this solar system, this radiatively-heated habitable zone contains the earth.

  13. Europa, tidally heated oceans, and habitable zones around giant planets.

    PubMed

    Reynolds, R T; McKay, C P; Kasting, J F

    1987-01-01

    Tidal dissipation in the satellites of a giant planet may provide sufficient heating to maintain an environment favorable to life on the satellite surface or just below a thin ice layer. In our own solar system, Europa, one of the Galilean satellites of Jupiter, could have a liquid ocean which may occasionally receive sunlight through cracks in the overlying ice shell. In such case, sufficient solar energy could reach liquid water that organisms similar to those found under Antarctic ice could grow. In other solar systems, larger satellites with more significant heat flow could represent environments that are stable over an order of Aeons and in which life could perhaps evolve. We define a zone around a giant planet in which such satellites could exist as a tidally-heated habitable zone. This zone can be compared to the habitable zone which results from heating due to the radiation of a central star. In our solar system, this radiatively-heated habitable zone contains the Earth.

  14. Visions of Our Planet's Atmosphere, Land & Oceans - ETheater Presentation

    NASA Technical Reports Server (NTRS)

    Hasler, F.

    2000-01-01

    The NASA/NOAA/AMS Earth Science Electronic Theater presents Earth science observations and visualizations in a historical perspective. Fly in from outer space to Florida and the KSC Visitor's Center. Go back to the early weather satellite images from the 1960s see them contrasted with the latest International global satellite weather movies including killer hurricanes & tornadic thunderstorms. See the latest spectacular images from NASA and NOAA remote sensing missions like GOES, NOAA, TRMM, SeaWiFS, Landsat7, & new Terra which will be visualized with state-of-the art tools. Shown in High Definition TV resolution (2048 x 768 pixels) are visualizations of hurricanes Lenny, Floyd, Georges, Mitch, Fran and Linda. See visualizations featured on covers of ma'gazines like Newsweek, TIME, National Geographic, Popular Science and on National & International Network TV. New Digital Earth visualization tools allow us to roam & zoom through massive global images including a Landsat tour of the US, with drill-downs into major cities using 1 m resolution spy-satellite technology from the Space Imaging IKONOS satellite. Spectacular new visualizations of the global atmosphere & oceans are shown. See massive dust storms sweeping across Africa. See ocean vortexes and currents that bring up the nutrients to feed tiny plankton and draw the fish, giant whales and fisherman. See the how the ocean blooms in response to these currents and El Nino/La Nina climate changes. The demonstration is interactively driven by a SGI Octane Graphics Supercomputer with dual CPUS, 5 Gigabytes of RAM and Terabyte disk using two projectors across the super sized Universe Theater panoramic screen.

  15. Emergence of two types of terrestrial planet on solidification of magma ocean.

    PubMed

    Hamano, Keiko; Abe, Yutaka; Genda, Hidenori

    2013-05-30

    Understanding the origins of the diversity in terrestrial planets is a fundamental goal in Earth and planetary sciences. In the Solar System, Venus has a similar size and bulk composition to those of Earth, but it lacks water. Because a richer variety of exoplanets is expected to be discovered, prediction of their atmospheres and surface environments requires a general framework for planetary evolution. Here we show that terrestrial planets can be divided into two distinct types on the basis of their evolutionary history during solidification from the initially hot molten state expected from the standard formation model. Even if, apart from their orbits, they were identical just after formation, the solidified planets can have different characteristics. A type I planet, which is formed beyond a certain critical distance from the host star, solidifies within several million years. If the planet acquires water during formation, most of this water is retained and forms the earliest oceans. In contrast, on a type II planet, which is formed inside the critical distance, a magma ocean can be sustained for longer, even with a larger initial amount of water. Its duration could be as long as 100 million years if the planet is formed together with a mass of water comparable to the total inventory of the modern Earth. Hydrodynamic escape desiccates type II planets during the slow solidification process. Although Earth is categorized as type I, it is not clear which type Venus is because its orbital distance is close to the critical distance. However, because the dryness of the surface and mantle predicted for type II planets is consistent with the characteristics of Venus, it may be representative of type II planets. Also, future observations may have a chance to detect not only terrestrial exoplanets covered with water ocean but also those covered with magma ocean around a young star.

  16. A Preliminary Study on the Circulation of an ocean covering a Synchronously Rotating Planet

    NASA Astrophysics Data System (ADS)

    Matsuo, H.; Ishiwatari, M.; Takehiro, S.; Hayashi, Y.; Nakajima, K.

    2012-12-01

    Recently, nearly 800 extrasolar planets have been detected. It seems that some of them present into habitable zone, in which planets can have ocean, and such planets rotate synchronously with their central stars. Ocean is necessary for life, and the circulation makes climate mild by heat transport on the earth. The earth is the only planet that has ocean in the solar system so that it has not been understood what oceanic circulation is like in another planets. The purpose of this study is prediction of oceanic circulation on extrasolar planets by using numerical simulation. As a first step, elementary consideration is made. The planet is almost entirely covered with ocean and whose rotation period corresponds with its orbital period. On synchronously rotating planets, the thermal contrast between day-hemisphere and night-hemisphere would be extreme. However, it may be lessend if there is significant zonal heat transport. The circulation in such conditions has not been known well. We performed a numerical experiment based on the linear shallow water equation, assuming that both the evaporation and the precipitation occur only on day-hemisphere (Noda et al., 2011). With these distributions of the evaporation and the precipitation, one may anticipate the circulation occurs in only day-hemisphere. However, the resulting calculation is characterized with zonally uniform zonal flow, which also covers night hemisphere. In addition, the intensity of the flow increases with time. That behavior can be understood by constructing asymptotic solution which is first degree in time. The importance of Coriolis force, which bends meridional flow to zonal flow, is identified. It is implied that, even when only day-hemisphere has the evaporation and precipitation, there may be significant amount of heat can be transported from the day-hemisphere to the night-hemisphere by the strong zonal flow. The growth of zonal flow would be stopped when the evaporation and the precipitation are

  17. On the Origins of Atmospheres and Oceans on Rocky Planets (Invited)

    NASA Astrophysics Data System (ADS)

    Elkins-Tanton, L. T.

    2013-12-01

    The earliest atmospheres of terrestrial planets are likely a combination of degassing of their own material with captured nebular gases. Degassing occurs during giant accretionary impacts and solidification of impact-induced melt. Observations from our solar system indicate that accreting materials have sufficient volatiles to build dense atmospheres and oceans and also to populate the planetary interior with volatiles for later degassing through volcanism. Many questions remain about the efficiency of degassing magma oceans, the degree to which later impacts remove atmospheres and oceans, and the speed at which cooling steam atmospheres collapse into oceans and thus elude stripping by the energetic young star. Atmospheric stripping is an especially current topic: How much distance from the star, planetary mass, and the possibility of a magnetic dynamo protect the early atmosphere from stripping? Nonetheless, compositional data from meteorites and comets indicate that our planets obtained their water from rocky accreting materials, and observations from missions indicate that accretionary impacts do not entirely remove volatiles. The low initial water contents required to produce oceans (as little as a few hundred ppm water) indicate that rocky planets may be generally expected to produce water oceans through degassing, and that an Earth-sized planet would cool to clement conditions in just a few to tens of millions of years. Thus, rocky planets are likely to accrete with sufficient water to form early oceans. Though this first atmosphere is subsequently changed and depleted past recognition, it may also have played an important role in determining the planet's surface and habitability. Later atmospheres and oceans will inevitably comprise some combination of the volatiles degassed during accretion and cooling, volatiles delivered during the tail of accretion, and volatiles released from later volcanism.

  18. Hypothetical Inverted Critical Zones for Subsurface Biospheres on Desert Planets and Icy Ocean Worlds

    NASA Astrophysics Data System (ADS)

    Boston, P. J.

    2015-10-01

    Earth as a model for cave habitable real-estate does not encompass other possibilities including desert planets like Mars, or icy ocean worlds viewed as planetary-scale water-filled caves in water ice bedrock which will have inverted Critical Zones.

  19. The Blue Planet: Seas & Oceans. Young Discovery Library Series.

    ERIC Educational Resources Information Center

    de Beauregard, Diane Costa

    This book is written for children ages 5 through 10. Part of a series designed to develop their curiosity, facinate them and educate them, this volume explores the physical and environmental characteristics of the world's oceans. Topics are: (1) human exploration; (2) the food chain; (3) coral reefs; (4) currents and tides; (5) waves; (6)…

  20. It's Only a Little Planet: A Primer for Ocean Studies.

    ERIC Educational Resources Information Center

    Meyland, Sarah J.

    Developed as part of the Day on the Bay Cruise Program, funded by the National Sea Grant Program, this learner's manual outlines ocean studies conducted on a seven-hour cruise of the Galveston Bay area. A description of the geology and human use of Galveston Bay follows a general introduction to coastal and estuarine ecology. Line drawings…

  1. CO2-dominated Atmosphere in Equilibrium with NH3-H2O Ocean: Application to Early Titan and Ocean Planets

    NASA Astrophysics Data System (ADS)

    Marounina, N.; Grasset, O.; Tobie, G.; Carpy, S.

    2015-12-01

    During the accretion of Titan, impact heating may have been sufficient to allow the global melting of water ice (Monteux et al. 2014) and the release of volatile compounds, with CO2 and NH3 as main constituents (Tobie et al. 2012). Thus, on primitive Titan, it is thought that a massive atmosphere was in contact with a global water ocean. Similar configurations may occur on temperate water-rich planets called ocean planets (Léger et al. 2004, Kitzmann et al. 2015).Due to its rather low solubility in liquid water, carbon dioxide is expected to be one of the major components in the atmosphere. The atmospheric amount of CO2 is a key parameter for assessing the thermal evolution of the planetary surface because of its strong greenhouse effect. However, ammonia significantly affects the solubility of CO2 in water and hence the atmosphere-ocean thermo-chemical equilibrium. For primitive Titan, estimating the mass, temperature and composition of the primitive atmosphere is important to determine mechanisms that led to the present-day N2-CH4 dominated atmosphere. Similarly, for ocean planets, the influence of ammonia on the atmospheric abundance in CO2 has consequences for the definition of the habitable zone.To investigate the atmospheric composition of the water-rich worlds for a wide range of initial compositions, we have developed a vapor-liquid equilibrium model of the NH3-CO2-H2O system, where we account for the non-ideal comportment of both vapor and liquid phases and the ion speciation of volatiles dissolved in the aqueous phase. We show that adding NH3 to the CO2-H2O binary system induces an efficient absorption of the CO2 in the liquid phase and thus a lower CO2 partial pressure in the vapor phase. Indeed, the CO2 partial pressure remains low for the CO2/NH3 ratio of liquid concentrations lower than 0.5.Assuming various initial compositions of Titan's global water ocean, we explore the thermal and compositional evolution of a massive primitive atmosphere using

  2. Strong ocean tidal flow and heating on moons of the outer planets.

    PubMed

    Tyler, Robert H

    2008-12-11

    Data from recent space missions have added strong support for the idea that there are liquid oceans on several moons of the outer planets, with Jupiter's moon Europa having received the most attention. But given the extremely cold surface temperatures and meagre radiogenic heat sources of these moons, it is still unclear how these oceans remain liquid. The prevailing conjecture is that these oceans are heated by tidal forces that flex the solid moon (rock plus ice) during its eccentric orbit, and that this heat entering the ocean does not rapidly escape because of the insulating layer of ice over the ocean surface. Here, however, I describe strong tidal dissipation (and heating) in the liquid oceans; I show that a subdominant and previously unconsidered tidal force due to obliquity (axial tilt of the moon with respect to its orbital plane) has the right form and frequency to resonantly excite large-amplitude Rossby waves in these oceans. In the specific case of Europa, the minimum kinetic energy of the flow associated with this resonance (7.3 x 10(18) J) is two thousand times larger than that of the flow excited by the dominant tidal forces, and dissipation of this energy seems large enough to be a primary ocean heat source.

  3. Oceanic Communities in a Changing Planet - The Tara Oceans Project (GSC8 Meeting)

    ScienceCinema

    Raes, Jeroen [University of Brussels

    2016-07-12

    The Genomic Standards Consortium was formed in September 2005. It is an international, open-membership working body which promotes standardization in the description of genomes and the exchange and integration of genomic data. The 2009 meeting was an activity of a five-year funding "Research Coordination Network" from the National Science Foundation and was organized held at the DOE Joint Genome Institute with organizational support provided by the JGI and by the University of California - San Diego. Jeroen Raes of the University of Brussels discusses the Tara-Oceans expedition at the Genomic Standards Consortium's 8th meeting at the DOE JGI in Walnut Creek, Calif. on Sept. 9, 2009

  4. Climate of Earth-Like Planets With and Without Ocean Heat Transport Orbiting a Range of M and K Stars

    NASA Technical Reports Server (NTRS)

    Kiang, N. Y.; Jablonski, Emma R.; Way, Michael J.; Del Genio, Anthony; Roberge, Aki

    2015-01-01

    The mean surface temperature of a planet is now acknowledged as insufficient to surmise its full potential habitability. Advancing our understanding requires exploration with 3D general circulation models (GCMs), which can take into account how gradients and fluxes across a planet's surface influence the distribution of heat, clouds, and the potential for heterogeneous distribution of liquid water. Here we present 3D GCM simulations of the effects of alternative stellar spectra, instellation, model resolution, and ocean heat transport, on the simulated distribution of heat and moisture of an Earth-like planet (ELP).

  5. Visions of our Planet's Atmosphere, Land and Oceans: NASA/NOAA E-Theater 2003

    NASA Technical Reports Server (NTRS)

    Hasler, Fritz

    2003-01-01

    The NASA/NOAA Electronic Theater presents Earth science observations from space in a spectacular way. Fly in from outer space to the conference location as well as the site of the 2002 Olympic Winter Games using data from NASA satellites and the IKONOS "Spy Satellite". See HDTV movie Destination Earth 2002 incorporating the Olympic Zooms, NBC footage of the 2002 Olympics, the shuttle, & the best NASA/NOAA Earth science visualizations. See the latest US and international global satellite weather movies including hurricanes, typhoons & "tornadoes". See the latest visualizations from NASA/NOAA and International remote sensing missions like Terra, Aqua, GOES, GMS, SeaWiFS, & Landsat. Feel the pulse of our planet. See how land vegetation, ocean plankton, clouds and temperatures respond to the sun & seasons. See vortexes and currents in the global oceans that bring up the nutrients to feed tiny algae and draw the fish, whales and fisherman. See the how the ocean blooms in response to these currents and El Nino/La Nina climate changes. See the city lights, fishing fleets, gas flares and bio-mass burning of the Earth at night observed by the "night-vision" DMSP satellite. The presentation will be made using the latest HDTV and video projection technology by: Dr. Fritz Hasler NASA/Goddard Space Flight Center

  6. Visions of our Planet's Atmosphere, Land and Oceans: NASA/NOAA E-Theater 2003

    NASA Technical Reports Server (NTRS)

    Hasler, Fritz

    2003-01-01

    The NASA/NOAA Electronic Theater presents Earth science observations from space in a spectacular way. Fly in from outer space to the conference location as well as the site of the 2002 Olympic Winter Games using data from NASA satellites and the IKONOS "Spy Satellite". See HDTV movie Destination Earth 2002 incorporating the Olympic Zooms, NBC footage of the 2002 Olympics, the shuttle, & the best NASA/NOAA Earth science visualizations. See the latest US and international global satellite weather movies including hurricanes, typhoons & "tornadoes". See the latest visualizations from NASA/NOAA and International remote sensing missions like Terra, Aqua, GOES, GMS , SeaWiFS, & Landsat. Feel the pulse of our planet. See how land vegetation, ocean plankton, clouds and temperatures respond to the sun & seasons. See vortexes and currents in the global oceans that bring up the nutrients to feed tiny algae and draw the fish, whales and fisherman. See the how the ocean blooms in response to these currents and El Nino/La Nina climate changes. See the city lights, fishing fleets, gas flares and bio-mass burning of the Earth at night observed by the the "night-vision" DMSP satellite. The presentation will be made using the latest HDTV and video projection technology by: Dr. Fritz Hasler NASA/Goddard Space Flight Center

  7. Visions of our Planet's Atmosphere, Land and Oceans: NASA/NOAA E-Theater 2003

    NASA Technical Reports Server (NTRS)

    Hasler, Fritz

    2003-01-01

    The NASA/NOAA Electronic Theater presents Earth science observations from space in a spectacular way. Fly in from outer space to the conference location as well as the site of the 2002 Olympic Winter Games using data from NASA satellites and the IKONOS 'Spy Satellite". See HDTV movie Destination Earth 2002 incorporating the Olympic Zooms, NBC footage of the 2002 Olympics, the shuttle, & the best NASA/NOAA Earth science visualizations. See the latest US and international global satellite weather movies including hurricanes, typhoons & "tornadoes". See the latest visualizations from NASA/NOAA and International remote sensing missions like Terra, Aqua, GOES, GMS, SeaWiFS, & Landsat. Feel the pulse of OUT planet. See how land vegetation, ocean plankton, clouds and temperatures respond to the sun & seasons. See vortexes and currents in the global oceans that bring up the nutrients to feed tiny algae and draw the fish, whales and fisherman. See the how the ocean blooms in response to these currents and El Nino/La Nina climate changes. See the city lights, fishing fleets, gas flares and bio-mass burning of the Earth at night observed by the "night-vision" DMSP satellite. The presentation will be made using the latest HDTV and video projection technology by: Dr. Fritz Hasler NASA/Goddard Space Flight Center.

  8. Visions of Our Planet's Atmosphere, Land and Oceans Electronic-Theater 2001

    NASA Technical Reports Server (NTRS)

    Hasler, A. F.; Einaudi, Franco (Technical Monitor)

    2001-01-01

    The NASA/NOAA/AMS Electronic Theater presents Earth science observations and visualizations in a historical perspective. Fly in from outer space to Fredericton New Brunswick. Drop in on the Kennedy Space Center and Park City Utah, site of the 2002 Olympics using 1 m IKONOS "Spy Satellite" data. Go back to the early weather satellite images from the 1960s and see them contrasted with the latest US and International global satellite weather movies including hurricanes & tornadoes. See the latest spectacular images from NASA/NOAA and Canadian remote sensing missions like Terra GOES, TRMM, SeaWiFS, Landsat 7, and Radarsat that are visualized & explained. See how High Definition Television (HDTV) is revolutionizing the way we communicate science in cooperation with the American Museum of Natural History in NYC. See dust storms in Africa and smoke plumes from fires in Mexico. See visualizations featured on Newsweek, TIME, National Geographic, Popular Science covers & National & International Network TV. New visualization tools allow us to roam & zoom through massive global images eg Landsat tours of the US, Africa, & New Zealand showing desert and mountain geology as well as seasonal changes in vegetation. See animations of the polar ice packs and the motion of gigantic Antarctic Icebergs from SeaWinds data. Spectacular new visualizations of the global atmosphere & oceans are shown. See massive dust storms sweeping across Africa. See vortexes and currents in the global oceans that bring up the nutrients to feed tiny plankton and draw the fish, whales and fisherman. See the how the ocean blooms in response to these currents and El Nino/La Nina climate changes. The demonstration is interactively driven by a SGI Onyx II Graphics Supercomputer with four CPUs, 8 Gigabytes of RAM and Terabyte of disk. With multiple projectors on a giant screen. See the city lights, fishing fleets, gas flares and bio-mass burning of the Earth at night observed by the "night-vision" DMSP

  9. Visions of our Planet's Atmosphere, Land and Oceans: NASA/NOAA Electronic Theater 2002

    NASA Technical Reports Server (NTRS)

    Haser, Fritz; Starr, David (Technical Monitor)

    2002-01-01

    The NASA/NOAA Electronic Theater presents Earth science observations and visualizations in a historical perspective. Fly in from outer space to the 2002 Winter Olympic Stadium Site of the Olympic Opening and Closing Ceremonies in Salt Lake City. Fly in and through Olympic Alpine Venues using 1 m IKONOS "Spy Satellite" data. Go back to the early weather satellite images from the 1960s and see them contrasted with the latest US and international global satellite weather movies including hurricanes and "tornadoes". See the latest visualizations of spectacular images from NASA/NOAA remote sensing missions like Terra, GOES, TRMM, SeaWiFS, Landsat 7 including new 1 - min GOES rapid scan image sequences of Nov 9th 2001 Midwest tornadic thunderstorms and have them explained. See how High-Definition Television (HDTV) is revolutionizing the way we communicate science. (In cooperation with the American Museum of Natural History in NYC) See dust storms in Africa and smoke plumes from fires in Mexico. See visualizations featured on the covers of Newsweek, TIME, National Geographic, Popular Science and on National and International Network TV. New computer software tools allow us to roam and zoom through massive global images e.g. Landsat tours of the US, and Africa, showing desert and mountain geology as well as seasonal changes in vegetation. See animations of the polar ice packs and the motion of gigantic Antarctic Icebergs from SeaWinds. data. Spectacular new visualizations of the global atmosphere and oceans are shown. See vortexes and currents in the global oceans that bring up the nutrients to feed tiny algae and draw the fish, whales and fisherman. See the how the ocean blooms in response to these currents and El Nino/La Nina climate changes. See the city lights, fishing fleets, gas flares and bio-mass burning of the Earth at night observed by the "night-vision" DMSP military satellite.

  10. Visions of Our Planet's Atmosphere, Land and Oceans: Electronic-Theater 2000

    NASA Technical Reports Server (NTRS)

    Hasler, A. F.

    2000-01-01

    The NASA/NOAA/AMS Earth Science Electronic Theater presents Earth science observations and visualizations in a historical perspective. Fly in from outer space to the Delaware Bay and Philadelphia area. Go back to the early weather satellite images from the 1960s see them contrasted with the latest International global satellite weather movies including killer tropical cyclones & tornadic thunderstorms. See the latest spectacular images from NASA, NOAA & UMETSAT remote sensing missions like GOES, Meteosat, NOAA, TRMM, SeaWiFS, Landsat7, & new Terra which will be visualized with state-of-the art tools. Shown in High Definition TV resolution (2048 x 768 pixels) are visualizations of hurricanes Lenny, Floyd, Georges, Mitch, Fran and Linda. see visualizations featured on covers of magazines like Newsweek, TIME, National Geographic, Popular Science and on National & International Network TV. New Digital Earth visualization tools allow us to roam & zoom through massive global images including Landsat tours of the US, and Africa with drill downs of major global cities using 1 m resolution commercialized spy-satellite technology from the Space Imaging IKONOS satellite. Spectacular new visualizations of the global atmosphere & oceans are shown. See massive dust storms sweeping across Africa. see ocean vortexes and currents that bring up the nutrients to feed tiny plankton and draw the fish, giant whales and fisherman. See the how the ocean blooms in response to these currents and El Nino/La Nina climate changes. The demonstration is interactively driven by a SGI Octane Graphics Supercomputer with dual CPUs, 5 Gigabytes of RAM and Terabyte disk using two projectors across a super sized panoramic screen.

  11. A Presentation of Spectacular Visualizations. Visions of Our Planet's Atmosphere, Land and Oceans: ETheater Presentation

    NASA Technical Reports Server (NTRS)

    Hasler, Fritz; Pierce, Hal; Einaudi, Franco (Technical Monitor)

    2000-01-01

    The NASA/NOAA/AMS Earth Science Electronic Theater presents Earth science observations and visualizations in a historical perspective. Fly in from outer space to Florida and the KSC Visitor's Center. Go back to the early weather satellite images from the 1960s see them contrasted with the latest International global satellite weather movies including killer hurricanes & tornadic thunderstorms. See the latest spectacular images from NASA and NOAA remote sensing missions like GOES, NOAA, TRMM, SeaWiFS, Landsat7, & new Terra which will be visualized with state-of-the art tools. Shown in High Definition TV resolution (2048 x 768 pixels) are visualizations of hurricanes Lenny, Floyd, Georges, Mitch, Fran and Linda. See visualizations featured on covers of magazines like Newsweek, TIME, National Geographic, Popular Science and on National & International Network TV. New Digital Earth visualization tools allow us to roam & zoom through massive global images including a Landsat tour of the US, with drill-downs into major cities using 1 m resolution spy-satellite technology from the Space Imaging IKONOS satellite. Spectacular new visualizations of the global atmosphere & oceans are shown. See massive dust storms sweeping across Africa. See ocean vortices and currents that bring up the nutrients to feed tiny plankton and draw the fish, giant whales and fisherman. See how the ocean blooms in response to these currents and El Nino/La Nina climate changes. The demonstration is interactively driven by a SGI Octane Graphics Supercomputer with dual CPUs, 5 Gigabytes of RAM and Terabyte disk using two projectors across the super sized Universe Theater panoramic screen.

  12. Visions of our Planet's Atmosphere, Land and Oceans: NASA/NOAA Electronic Theater 2002

    NASA Technical Reports Server (NTRS)

    Hasler, A. F.; Starr, David (Technical Monitor)

    2002-01-01

    The NASA/NOAA Electronic Theater presents Earth science observations and visualizations in a historical perspective. Fly in from outer space to the Olympic Medals Plaza, the new Gateway Center, and the University of Utah Stadium Site of the Olympic Opening and Closing Ceremonies in Salt Lake City. Fly in and through the Park City, and Snow Basin sites of the 2002 Winter Olympic Alpine Venues using 1 m IKONOS "Spy Satellite" data. See the four seasons of the Wasatch Front as observed by Landsat 7 at 15m resolution and watch the trees turn color in the Fall, snow come and go in the mountains and the reservoirs freeze and melt. Go back to the early weather satellite images from the 1960s and see them contrasted with the latest US and international global satellite weather movies Including hurricanes & "tornadoes". See the latest visualizations of spectacular images from NASA/NOAA remote sensing missions like Terra, GOES, TRMM, SeaWiFS, Landsat 7 including new 1 - min GOES rapid scan image sequences of Nov 9th 2001 Midwest tornadic thunderstorms and have them explained. See how High-Definition Television (HDTV) is revolutionizing the way we communicate science. (In cooperation with the American Museum of Natural History in NYC) See dust storms in Africa and smoke plumes from fires in Mexico. See visualizations featured on the covers Of Newsweek, TIME, National Geographic, Popular Science & on National & International Network TV. New computer software. tools allow us to roam & zoom through massive global images e.g. Landsat tours of the US, and Africa, showing desert and mountain geology as well as seasonal changes in vegetation. See animations of the polar ice packs and the motion of gigantic Antarctic Icebergs from SeaWinds data. Spectacular new visualizations of the global atmosphere & oceans are shown. See vertexes and currents in the global oceans that bring up the nutrients to feed tin) algae and draw the fish, whales and fisherman. See the how the ocean blooms in

  13. Visions of our Planet's Atmosphere, Land and Oceans: NASA/NOAA Electronic Theater 2002

    NASA Technical Reports Server (NTRS)

    Hasler, A. F.; Starr, David (Technical Monitor)

    2001-01-01

    The NASA/NOAA Electronic Theater presents Earth science observations and visualizations in a historical perspective. Fly in from outer space to the Olympic Medals Plaza, the new Gateway Center, and the University of Utah Stadium Site of the Olympic Opening and Closing Ceremonies in Salt Lake City. Fly in and through the Park City, and Snow Basin sites of the 2002 Winter Olympic Alpine Venues using 1 m IKONOS "Spy Satellite" data. See the four seasons of the Wasatch Front as observed by Landsat 7 at 15m resolution and watch the trees turn color in the Fall, snow come and go in the mountains and the reservoirs freeze and melt. Go back to the early weather satellite images from the 1960s and see them contrasted with the latest US and international global satellite weather movies including hurricanes & "tornadoes". See the latest visualizations of spectacular images from NASA/NOAA remote sensing missions like Terra, GOES, TRMM, SeaWiFS, Landsat 7 including new 1 - min GOES rapid scan image sequences of Nov 9th 2001 Midwest tornadic thunderstorms and have them explained. See how High-Definition Television (HDTV) is revolutionizing the way we communicate science. (In cooperation with the American Museum of Natural History in NYC) See dust storms in Africa and smoke plumes from fires in Mexico. See visualizations featured on the covers of Newsweek, TIME, National Geographic, Popular Science & on National & International Network TV. New computer software tools allow us to roam & zoom through massive global images e.g. Landsat tours of the US, and Africa, showing desert and mountain geology as well as seasonal changes in vegetation. See animations of the polar ice packs and the motion of gigantic Antarctic Icebergs from SeaWinds data. Spectacular new visualizations of the global atmosphere & oceans are shown. See vortexes and currents in the global oceans that bring up the nutrients to feed tiny algae and draw the fish, whales and fisherman. See the how the ocean blooms in

  14. Electronic-Theater 2001: Visions of Our Planet's Atmosphere, Land and Oceans

    NASA Technical Reports Server (NTRS)

    Hasler, Authur; Starr, David OC. (Technical Monitor)

    2001-01-01

    The NASA/NOAA/AMS Electronic Theater presents Earth science observations and visualizations in a historical perspective. Fly in from outer space to Wisconsin, Madison and the Monona Terrace Center. Drop in on the Kennedy Space Center and Park City Utah, site of the 2002 Olympics using I m IKONOS "Spy Satellite" data. Go back to the early weather satellite images from the 1960s pioneered by UW. Scientists and see them contrasted with the latest US and International global satellite weather movies including hurricanes & tornadoes. See the latest spectacular images from NASA/NOAA remote sensing missions like Terra GOES, TRMM, SeaWiFS, Landsat 7 that are visualized & explained. See how High Definition Television (HDTV) is revolutionizing the way we communicate science in cooperation with the American Museum of Natural History in NYC. See dust storms in Africa and smoke plumes from fires in Mexico. See visualizations featured on Newsweek, TIME, National Geographic, Popular Science covers & National & International Network TV. New visualization tools allow us to roam & zoom through massive global images eg Landsat tours of the US, Africa, & New Zealand showing desert and mountain geology as well as seasonal changes in vegetation. See animations of the polar ice packs and the motion of gigantic Antarctic Icebergs from SeaWinds data. Spectacular new visualizations of the global atmosphere & oceans are shown. See massive dust storms sweeping across Africa. See vortices and currents in the global oceans that bring up the nutrients to feed tiny plankton and draw the fish, whales and fisherman. See the how the ocean blooms in response to these currents and El Nina/La Nina climate changes. The demonstration is interactively driven by a SGI Onyx 11 Graphics Supercomputer with four CPUs, 8 Gigabytes of RAM and Terabyte of disk. With five projectors on a giant IMAX sized 18 x 72 ft screen. See the city lights, fishing fleets, gas flares and bio-mass burning of the Earth at night

  15. The Torque of the Planet: NASA Researcher Uses NCCS Computers to Probe Atmosphere-Land-Ocean Coupling

    NASA Technical Reports Server (NTRS)

    2002-01-01

    The study of Earth science is like a giant puzzle, says Braulio Sanchez. "The more you know about the individual pieces, the easier it is to fit them together." A researcher with Goddard's Space Geodesy Branch, Sanchez has been using NCCS supercomputer and mass storage resources to show how the angular momenta of the atmosphere, the oceans, and the solid Earth are dynamically coupled. Sanchez has calculated the magnitude of atmospheric torque on the planet and has determined some of the possible effects that torque has on Earth's rotation.

  16. Atmospheres and Oceans of Rocky Planets In and Beyond the Habitable Zones of M dwarfs

    NASA Astrophysics Data System (ADS)

    Tian, Feng

    2015-12-01

    he evolution of M dwarfs during their pre-main-sequence phase causes rocky planets in and beyond the habitable zones these stars to be in the runaway and moist greenhouse states. This scenario has been studied by three groups of researchers recently (Ramirez and Kaltenegger 2014, Tian and Ida 2015, Luger and Barnes 2015), and their consensus is that massive amount of water could have been lost during this time -- early evolution of M dwarfs could have changed the water contents of rocky planets around them, which could strongly influence the habitability of rocky planets around low mass stars. It has been proposed that dense oxygen dominant atmospheres (up to 2000 bars, Luger and Barnes 2015) because of rapid water loss. Is this true? If so, what's the condition for such atmospheres to exist and can they be maintained? On the other hand, what's the likelihood for sub-Neptunes to shrink into habitable planets under such environment? In general how is the habitability of planets around M dwarfs different from those around Sun-type stars? These are the questions we will attempt to address in this work.

  17. The Biological Big Bang: The First Oceans of Primordial Planets at 2-8 Myr Explains Hoyle-Wickramasinghe Cometary Panspermia and a Primordial LUCA

    NASA Astrophysics Data System (ADS)

    Gibson, Carl H.; Wickramasinghe, N. C.; Schild, R. E.

    2011-10-01

    Hydrogravitional-dynamics (HGD) cosmology of Gibson/Schild 1996 predicts that the primordial H-He4 gas of big bang nucleosynthesis became proto-globular-star-cluster clumps of Earth-mass planets at 300 Kyr. The first stars formed from mergers of these 3000 K gas planets. Chemicals C, N, O, Fe etc. created by stars and supernovae then seeded many of the reducing hydrogen gas planets with oxides to give them hot water oceans with metallic iron-nickel cores. Water oceans at critical temperature 647 K then hosted the first organic chemistry and the first life, distributed to the 1080 planets of the cosmological big bang by comets produced by the new (HGD) planet-merger star formation mechanism. The biological big bang scenario occurs between 2 Myr when liquid oceans condensed and 8 Myr when they froze. HGD cosmology explains, very naturally, the Hoyle/Wickramasinghe concept of cometary panspermia by giving a vast, hot, nourishing, cosmological primordial soup for abiogenesis, and the means for transmitting the resulting life forms and their evolving chemical mechanisms widely throughout the universe from the resulting RNA last-universal-common-ancestor LUCA. A primordial astrophysical basis is provided for astrobiology by HGD cosmology. Concordance ΛCDMHC cosmology is rendered obsolete by the observation of complex life on Earth.

  18. The biological big bang: the first oceans of primordial planets at 2-8 million years explain Hoyle/Wickramasinghe cometary panspermia

    NASA Astrophysics Data System (ADS)

    Gibson, Carl H.

    2011-10-01

    Hydrogravitional-dynamics (HGD) cosmology of Gibson/Schild 1996 predicts that the primordial H-He4 gas of big bang nucleosynthesis became proto-globular-star-cluster clumps of Earth-mass planets at 300 Kyr. The first stars formed from mergers of these 3000 K gas planets. Chemicals C, N, O, Fe etc. created by stars and supernovae then seeded many of the reducing hydrogen gas planets with oxides to give them hot water oceans with metallic iron-nickel cores. Water oceans at critical temperature 647 K then hosted the first organic chemistry and the first life, distributed to the 1080 planets of the cosmological big bang by comets produced by the new (HGD) planet-merger star formation mechanism. The biological big bang scenario occurs between 2 Myr when liquid oceans condensed and 8 Myr when they froze. HGD cosmology explains, very naturally, the Hoyle/Wickramasinghe concept of cometary panspermia by giving a vast, hot, nourishing, cosmological primordial soup for abiogenesis, and the means for transmitting the resulting life forms and their evolving chemical mechanisms widely throughout the universe. A primordial astrophysical basis is provided for astrobiology by HGD cosmology. Concordance ΛCDMHC cosmology is rendered obsolete by the observation of complex life on Earth.

  19. THE ORBITAL PHASES AND SECONDARY TRANSITS OF KEPLER-10b. A PHYSICAL INTERPRETATION BASED ON THE LAVA-OCEAN PLANET MODEL

    SciTech Connect

    Rouan, D.; Deeg, H. J.; Demangeon, O.; Samuel, B.; Cavarroc, C.; Leger, A.; Fegley, B.

    2011-11-10

    The Kepler mission has made an important observation: the first detection of photons from a terrestrial planet by observing its phase curve (Kepler-10b). This opens a new field in exoplanet science: the possibility of obtaining information about the atmosphere and surface of rocky planets, objects of prime interest. In this Letter, we apply the Lava-ocean model to interpret the observed phase curve. The model, a planet without atmosphere and a surface partially made of molten rocks, has been proposed for planets of the class of CoRoT-7b, i.e., rocky planets very close to their star (at a few stellar radii). Kepler-10b is a typical member of this family. It predicts that the light from the planet has an important emission component in addition to the reflected one, even in the Kepler spectral band. Assuming an isotropical reflection of light by the planetary surface (Lambertian-like approximation), we find that a Bond albedo of {approx}50% can account for the observed amplitude of the phase curve, as opposed to a first attempt where an unusually high value was found. We propose a physical process to explain this still large value of the albedo. The overall interpretation can be tested in the future with instruments such as the James Webb Space Telescope or the Exoplanet Characterization Observatory. Our model predicts a spectral dependence that is clearly distinguishable from that of purely reflected light and from that of a planet at a uniform temperature.

  20. A Perspective of Our Planet's Atmosphere, Land, and Oceans: A View from Space

    NASA Technical Reports Server (NTRS)

    King, Michael D.; Graham, Steven M.

    2002-01-01

    A birds eye view of the Earth from afar and up close reveals the power and magnificence of the Earth and juxtaposes the simultaneous impacts and powerlessness of humankind. The NASA Electronic Theater presents Earth science observations and visualizations in true high definition (HD) format. See the latest spectacular images from NASA & NOAA remote sensing missions like GOES, TRMM, Landsat 7, QuikScat, and Terra, which will be visualized and explained in the context of global change. Marvel at visualizations of global data sets currently available from Earth orbiting satellites, including the Earth at night with its city lights, aerosols from biomass burning, and global cloud properties. See the dynamics of vegetation growth and decay over South America over 17 years, and its contrast to the North American and Africa continents. Spectacular new visualizations of the global atmosphere & oceans will be shown. See massive dust storms sweeping across Africa and across the Atlantic to the Caribbean and Amazon basin. See ocean vortexes and currents that bring up the nutrients to feed tiny phytoplankton and draw the fish, giant whales and fisher- man. See how the ocean blooms in response to these currents and El Nino/La Nina climate changes. We will illustrate these and other topics with a dynamic theater-style presentation, along with animations of satellite launch deployments and orbital mapping to highlight aspects of Earth observations from space.

  1. A Perspective of Our Planet's Atmosphere, Land, and Oceans: A View from Space

    NASA Technical Reports Server (NTRS)

    King, Michael D.; Tucker, Compton

    2002-01-01

    A birds eye view of the Earth from afar and up close reveals the power and magnificence of the Earth and juxtaposes the simultaneous impacts and powerlessness of humankind. The NASA Electronic Theater presents Earth science observations and visualizations in an historical perspective. Fly in from outer space to South America with its Andes Mountains and the glaciers of Patagonia, ending up close and personal in Buenos Aires. See the latest spectacular images from NASA & NOAA remote sensing missions like GOES, TRMM, Landsat 7, QuikScat, and Terra, which will be visualized and explained in the context of global change. See visualizations of global data sets currently available from Earth orbiting satellites, including the Earth at night with its city lights, aerosols from biomass burning in South America and Africa, and global cloud properties. See the dynamics of vegetation growth and decay over South America over 17 years, and its contrast to the North American and Africa continents. New visualization tools allow us to roam & zoom through massive global mosaic images from the Himalayas to the dynamics of the Pacific Ocean that affect the climate of South and North America. New visualization tools allow us to roam & zoom through massive global mosaic images including Landsat and Terra tours of South America and Africa showing land use and land cover change from Patagonia to the Amazon Basin, including the Andes Mountains, the Pantanal, and the Bolivian highlands. Landsat flyins to Rio Di Janeiro and Buenos Aires will be shows to emphasize the capabilities of new satellite technology to visualize our natural environment. Spectacular new visualizations of the global atmosphere & oceans are shown. See massive dust storms sweeping across Africa and across the Atlantic to the Caribbean and Amazon basin. See ocean vortexes and currents that bring up the nutrients to feed tiny phytoplankton and draw the fish, giant whales and fisherman. See how the ocean blooms in response

  2. The effects of cloud radiative forcing on an ocean-covered planet

    NASA Technical Reports Server (NTRS)

    Randall, David A.

    1990-01-01

    Cumulus anvil clouds, whose importance has been emphasized by observationalists in recent years, exert a very powerful influence on deep tropical convection by tending to radiatively destabilize the troposphere. In addition, they radiatively warm the column in which they reside. Their strong influence on the simulated climate argues for a much more refined parameterization in the General Circulation Model (GCM). For Seaworld, the atmospheric cloud radiative forcing (ACRF) has a powerful influence on such basic climate parameters as the strength of the Hadley circulation, the existence of a single narrow InterTropical Convergence Zone (ITCZ), and the precipitable water content of the atmosphere. It seems likely, however, that in the real world the surface CRF feeds back negatively to suppress moist convection and the associated cloudiness, and so tends to counteract the effects of the ACRF. Many current climate models have fixed sea surface temperatures but variable land-surface temperatures. The tropical circulations of such models may experience a position feedback due to ACRF over the oceans, and a negative or weak feedback due to surface CRF over the land. The overall effects of the CRF on the climate system can only be firmly established through much further analysis, which can benefit greatly from the use of a coupled ocean-atmospheric model.

  3. The Polar Ocean in a Warming Planet: Understanding for managing a unique resource of the Humankind

    NASA Astrophysics Data System (ADS)

    Azzolini, R.; Campus, P.; Weber, J.

    2012-04-01

    There is no doubt that changes in the Polar Regions are of great significance at the global level, such as having far-reaching effects on atmospheric and ocean circulation. Changes in ocean currents, temperature conditions, ice cover and reduction of permafrost regions are having impacts on marine and terrestrial ecosystems in the Arctic Regions of Europe and Northern Hemisphere. Human activity is putting pressure on the environment in these regions; maritime transport between Europe and Asia through the northern sea route and accessibility conditions to hidden Arctic resources as well as new technologies of exploitation will have a significant impact on the marine environment, on the living resources and on the regional social organization and needs. There are still unresolved issues related to national claims on continental shelf and sea areas that involve international law; in these respects science can provide crucial elements for supporting political agreements. Such scenarios will present new opportunities for economic activities, but also risks which will result in new demands for marine management, monitoring systems, emergency response systems, search and rescue services as well as closer international cooperation. It will also require the development of an international regime based on the improvement of the present regulations on exploration, accessibility, exploitation and liability. Dialogue and international agreements based on scientific evidences and foresight are key elements for finding solutions. On the opposite hemisphere, the ocean surrounding Antarctica plays a primary role in all global climatic processes, through the annual sea ice evolution, the circum-Antarctic circulation driving the exchange of heat between low and high latitudes and the atmospheric circulation, through the density bottom currents that affect the global Thermohaline circulation (THC), and the biogeochemical cycles that have peculiar characteristics in the icy Antarctic

  4. Take a Planet Walk

    ERIC Educational Resources Information Center

    Schuster, Dwight

    2008-01-01

    Physical models in the classroom "cannot be expected to represent the full-scale phenomenon with complete accuracy, not even in the limited set of characteristics being studied" (AAAS 1990). Therefore, by modifying a popular classroom activity called a "planet walk," teachers can explore upper elementary students' current understandings; create an…

  5. Extrasolar Planets

    NASA Astrophysics Data System (ADS)

    Deeg, Hans; Belmonte, Juan Antonio; Aparicio, Antonio

    2012-03-01

    Participants; Preface; Acknowledgements; 1. Extrasolar planet detection methods Laurance R. Doyle; 2. Statistical properties of exoplanets Stéphane Udry; 3. Characterizing extrasolar planets Timothy M. Brown; 4. From clouds to planet systems: formation and evolution of stars and planets Günther Wuchterl; 5. Abundances in stars with extrasolar planetary systems Garik Israelian; 6. Brown dwarfs: the bridge between stars and planets Rafael Rebolo; 7. The perspective: a panorama of the Solar System Agustín Sánchez-Lavega; 8. Habitable planets around the Sun and other stars James F. Kasting; 9. Biomarkers of extrasolar planets and their observability Franck Selsis, Jimmy Paillet and France Allard; Index.

  6. Extrasolar Planets

    NASA Astrophysics Data System (ADS)

    Deeg, Hans; Belmonte, Juan Antonio; Aparicio, Antonio

    2007-10-01

    Participants; Preface; Acknowledgements; 1. Extrasolar planet detection methods Laurance R. Doyle; 2. Statistical properties of exoplanets Stéphane Udry; 3. Characterizing extrasolar planets Timothy M. Brown; 4. From clouds to planet systems: formation and evolution of stars and planets Günther Wuchterl; 5. Abundances in stars with extrasolar planetary systems Garik Israelian; 6. Brown dwarfs: the bridge between stars and planets Rafael Rebolo; 7. The perspective: a panorama of the Solar System Agustín Sánchez-Lavega; 8. Habitable planets around the Sun and other stars James F. Kasting; 9. Biomarkers of extrasolar planets and their observability Franck Selsis, Jimmy Paillet and France Allard; Index.

  7. A simple 1-D radiative-convective atmospheric model designed for integration into coupled models of magma ocean planets

    NASA Astrophysics Data System (ADS)

    Marcq, E.

    2012-01-01

    In order to understand the early history of telluric interiors and atmospheres during the ocean magma stage, a coupled interior-atmosphere-escape model is being developed. This paper describes the atmospheric part and its first preliminary results. A unidimensional, radiative-convective, H2O-CO2 atmosphere is modeled following a vertical T(z) profile similar to Kasting (1988) and Abe and Matsui (1988). Opacities in the thermal IR are then computed using a k-correlated code (KSPECTRUM), tabulated continuum opacities for H2O-H2O and CO2-CO2 absorption, and water or sulphuric acid clouds in the moist convective zone (whenever present). The first results show the existence of two regimes depending on the relative value of the surface temperature Ts compared to a threshold temperature Tc depending on the total gaseous inventory. For Ts < Tc, efficient blanketing results in a cool upper atmosphere, a cloud cover, and a long lifetime for the underneath magma ocean with a net thermal IR flux between 160 and 200 Wm-2. For Ts > Tc, the blanketing is not efficient enough to prevent large radiative heat loss to space through a hot, cloudless atmosphere. Our current calculations may underestimate the thermal flux in the case of hot surfaces with little gaseous content in the atmosphere.

  8. Visions of our Planet's Atmosphere, Land and Oceans: NASA/NOAA Electronic-Theater 2002. Spectacular Visualizations of our Blue Marble

    NASA Technical Reports Server (NTRS)

    Hasler, A. F.; Starr, David (Technical Monitor)

    2002-01-01

    Spectacular Visualizations of our Blue Marble The NASA/NOAA Electronic Theater presents Earth science observations and visualizations in a historical perspective. Fly in from outer space to the 2002 Winter Olympic Stadium Site of the Olympic Opening and Closing Ceremonies in Salt Lake City. Fly in and through Olympic Alpine Venues using 1 m IKONOS "Spy Satellite" data. Go back to the early weather satellite images from the 1960s and see them contrasted with the latest US and international global satellite weather movies including hurricanes & "tornadoes". See the latest visualizations of spectacular images from NASA/NOAA remote sensing missions like Terra, GOES, TRMM, SeaWiFS, Landsat 7 including new 1 - min GOES rapid scan image sequences of Nov 9th 2001 Midwest tornadic thunderstorms and have them explained. See how High-Definition Television (HDTV) is revolutionizing the way we communicate science. (In cooperation with the American Museum of Natural History in NYC). See dust storms in Africa and smoke plumes from fires in Mexico. See visualizations featured on the covers of Newsweek, TIME, National Geographic, Popular Science & on National & International Network TV. New computer software tools allow us to roam & zoom through massive global images e.g. Landsat tours of the US, and Africa, showing desert and mountain geology as well as seasonal changes in vegetation. See animations of the polar ice packs and the motion of gigantic Antarctic Icebergs from SeaWinds data. Spectacular new visualizations of the global atmosphere & oceans are shown. See vertexes and currents in the global oceans that bring up the nutrients to feed tiny algae and draw the fish, whales and fisherman. See the how the ocean blooms in response to these currents and El Nicola Nina climate changes. See the city lights, fishing fleets, gas flares and biomass burning of the Earth at night observed by the "night-vision" DMSP military satellite.

  9. Planet Formation

    NASA Technical Reports Server (NTRS)

    Lissauer, Jack J.; Fonda, Mark (Technical Monitor)

    2002-01-01

    Modern theories of star and planet formation and of the orbital stability of planetary systems are described and used to discuss possible characteristics of undiscovered planetary systems. The most detailed models of planetary growth are based upon observations of planets and smaller bodies within our own Solar System and of young stars and their environments. Terrestrial planets are believed to grow via pairwise accretion until the spacing of planetary orbits becomes large enough that the configuration is stable for the age of the system. Giant planets begin their growth as do terrestrial planets, but they become massive enough that they are able to accumulate substantial amounts of gas before the protoplanetary disk dissipates. These models predict that rocky planets should form in orbit about most single stars. It is uncertain whether or not gas giant planet formation is common, because most protoplanetary disks may dissipate before solid planetary cores can grow large enough to gravitationally trap substantial quantities of gas. A potential hazard to planetary systems is radial decay of planetary orbits resulting from interactions with material within the disk. Planets more massive than Earth have the potential to decay the fastest, and may be able to sweep up smaller planets in their path. The implications of the giant planets found in recent radial velocity searches for the abundances of habitable planets are discussed, and the methods that are being used and planned for detecting and characterizing extrasolar planets are reviewed.

  10. Migrating Planets

    NASA Astrophysics Data System (ADS)

    Murray, N.; Hansen, B.; Holman, M.; Tremaine, S.

    1998-01-01

    A planet orbiting in a disk of planetesimals can experience an instability in which it migrates to smaller orbital radii. Resonant interactions between the planet and planetesimals remove angular momentum from the planetesimals, increasing their eccentricities. Subsequently, the planetesimals either collide with or are ejected by the planet, reducing the semimajor axis of the planet. If the surface density of planetesimals exceeds a critical value, corresponding to 0.03 solar masses of gas inside the orbit of Jupiter, the planet will migrate inward a large distance. This instability may explain the presence of Jupiter-mass objects in small orbits around nearby stars.

  11. Extrasolar planets

    PubMed Central

    Lissauer, Jack J.; Marcy, Geoffrey W.; Ida, Shigeru

    2000-01-01

    The first known extrasolar planet in orbit around a Sun-like star was discovered in 1995. This object, as well as over two dozen subsequently detected extrasolar planets, were all identified by observing periodic variations of the Doppler shift of light emitted by the stars to which they are bound. All of these extrasolar planets are more massive than Saturn is, and most are more massive than Jupiter. All orbit closer to their stars than do the giant planets in our Solar System, and most of those that do not orbit closer to their star than Mercury is to the Sun travel on highly elliptical paths. Prevailing theories of star and planet formation, which are based on observations of the Solar System and of young stars and their environments, predict that planets should form in orbit about most single stars. However, these models require some modifications to explain the properties of the observed extrasolar planetary systems. PMID:11035782

  12. Extrasolar planets.

    PubMed

    Lissauer, J J; Marcy, G W; Ida, S

    2000-11-07

    The first known extrasolar planet in orbit around a Sun-like star was discovered in 1995. This object, as well as over two dozen subsequently detected extrasolar planets, were all identified by observing periodic variations of the Doppler shift of light emitted by the stars to which they are bound. All of these extrasolar planets are more massive than Saturn is, and most are more massive than Jupiter. All orbit closer to their stars than do the giant planets in our Solar System, and most of those that do not orbit closer to their star than Mercury is to the Sun travel on highly elliptical paths. Prevailing theories of star and planet formation, which are based on observations of the Solar System and of young stars and their environments, predict that planets should form in orbit about most single stars. However, these models require some modifications to explain the properties of the observed extrasolar planetary systems.

  13. Terrestrial Planets Accreted Dry

    NASA Astrophysics Data System (ADS)

    Albarede, F.; Blichert-Toft, J.

    2007-12-01

    Plate tectonics shaped the Earth, whereas the Moon is a dry and inactive desert. Mars probably came to rest within the first billion years of its history, and Venus, although internally very active, has a dry inferno for its surface. The strong gravity field of a large planet allows for an enormous amount of gravitational energy to be released, causing the outer part of the planetary body to melt (magma ocean), helps retain water on the planet, and increases the pressure gradient. The weak gravity field and anhydrous conditions prevailing on the Moon stabilized, on top of its magma ocean, a thick buoyant plagioclase lithosphere, which insulated the molten interior. On Earth, the buoyant hydrous phases (serpentines) produced by reactions between the terrestrial magma ocean and the wet impactors received from the outer Solar System isolated the magma and kept it molten for some few tens of million years. The elemental distributions and the range of condensation temperatures show that the planets from the inner Solar System accreted dry. The interior of planets that lost up to 95% of their K cannot contain much water. Foundering of their wet surface material softened the terrestrial mantle and set the scene for the onset of plate tectonics. This very same process may have removed all the water from the surface of Venus 500 My ago and added enough water to its mantle to make its internal dynamics very strong and keep the surface very young. Because of a radius smaller than that of the Earth, not enough water could be drawn into the Martian mantle before it was lost to space and Martian plate tectonics never began. The radius of a planet therefore is the key parameter controlling most of its evolutional features.

  14. From planetesimals to planets: volatile molecules

    NASA Astrophysics Data System (ADS)

    Marboeuf, Ulysse; Thiabaud, Amaury; Alibert, Yann; Cabral, Nahuel; Benz, Willy

    2014-10-01

    Context. Solar and extrasolar planets are the subject of numerous studies aiming to determine their chemical composition and internal structure. In the case of extrasolar planets, the composition is important as it partly governs their potential habitability. Moreover, observational determination of chemical composition of planetary atmospheres are becoming available, especially for transiting planets. Aims: The present works aims at determining the chemical composition of planets formed in stellar systems of solar chemical composition. The main objective of this work is to provide valuable theoretical data for models of planet formation and evolution, and future interpretation of chemical composition of solar and extrasolar planets. Methods: We have developed a model that computes the composition of ices in planets in different stellar systems with the use of models of ice and planetary formation. Results: We provide the chemical composition, ice/rock mass ratio and C:O molar ratio for planets in stellar systems of solar chemical composition. From an initial homogeneous composition of the nebula, we produce a wide variety of planetary chemical compositions as a function of the mass of the disk and distance to the star. The volatile species incorporated in planets are mainly composed of H2O, CO, CO2, CH3OH, and NH3. Icy or ocean planets have systematically higher values of molecular abundances compared to giant and rocky planets. Gas giant planets are depleted in highly volatile molecules such as CH4, CO, and N2 compared to icy or ocean planets. The ice/rock mass ratio in icy or ocean and gas giant planets is, respectively, equal at maximum to 1.01 ± 0.33 and 0.8 ± 0.5, and is different from the usual assumptions made in planet formation models, which suggested this ratio to be 2-3. The C:O molar ratio in the atmosphere of gas giant planets is depleted by at least 30% compared to solar value.

  15. Extreme Planets

    NASA Technical Reports Server (NTRS)

    2006-01-01

    This artist's concept depicts the pulsar planet system discovered by Aleksander Wolszczan in 1992. Wolszczan used the Arecibo radio telescope in Puerto Rico to find three planets - the first of any kind ever found outside our solar system - circling a pulsar called PSR B1257+12. Pulsars are rapidly rotating neutron stars, which are the collapsed cores of exploded massive stars. They spin and pulse with radiation, much like a lighthouse beacon. Here, the pulsar's twisted magnetic fields are highlighted by the blue glow.

    All three pulsar planets are shown in this picture; the farthest two from the pulsar (closest in this view) are about the size of Earth. Radiation from charged pulsar particles would probably rain down on the planets, causing their night skies to light up with auroras similar to our Northern Lights. One such aurora is illustrated on the planet at the bottom of the picture.

    Since this landmark discovery, more than 160 extrasolar planets have been observed around stars that are burning nuclear fuel. The planets spotted by Wolszczan are still the only ones around a dead star. They also might be part of a second generation of planets, the first having been destroyed when their star blew up. The Spitzer Space Telescope's discovery of a dusty disk around a pulsar might represent the beginnings of a similarly 'reborn' planetary system.

  16. Popular Culture and Curricula.

    ERIC Educational Resources Information Center

    Browne, Ray B., Ed.; Ambrosetti, Ronald J., Ed.

    The seven essays in this publication, including four read at the fall 1969 American Studies Association meeting, attempt to present both the nature of popular culture study and a guide for teachers of popular culture courses. Papers are (1) "Popular Culture: Notes toward a Definition" by Ray B. Browne; (2) "Can Popular Culture Save American…

  17. Primordial Planet Formation

    NASA Astrophysics Data System (ADS)

    Schild, Rudolph E.; Gibson, Carl H.

    Recent spacecraft observations exploring solar system properties impact standard paradigms of the formation of stars, planets and comets. We stress the unexpected cloud of microscopic dust resulting from the DEEP IMPACT mission, and the existence of molten nodules in STARDUST samples. And the theory of star formation does not explain the common occurrence of binary and multiple star systems in the standard gas fragmentation scenario. No current theory of planet formation can explain the iron core of the earth, under oceans of water. These difficulties are avoided in a scenario where the planet mass objects form primordially and are today the baryonic dark matter. They have been detected in quasar microlensing and anomalous quasar radio brightening bursts. The primordial planets often concentrate together to form a star, with residual matter seen in pre-stellar accretion discs around the youngest stars. These primordial planet mass bodies were formed of hydrogen-helium, aggregated in dense clumps of a trillion at the time of plasma neutralization 380,000 years after the big bang. Most have been frozen and invisible, but are now manifesting themselves in numerous ways as sensitive modern space telescopes become operational. Their key detection signature is their thermal emission spectrum, pegged at the 13.8 degrees Kelvin triple point of hydrogen, the baryonic dark matter (Staplefeldt et al. 1999).

  18. Conditions for oceans on Earth-like planets orbiting within the habitable zone: importance of volcanic CO{sub 2} degassing

    SciTech Connect

    Kadoya, S.; Tajika, E. E-mail: tajika@astrobio.k.u-tokyo.ac.jp

    2014-08-01

    Earth-like planets in the habitable zone (HZ) have been considered to have warm climates and liquid water on their surfaces if the carbonate-silicate geochemical cycle is working as on Earth. However, it is known that even the present Earth may be globally ice-covered when the rate of CO{sub 2} degassing via volcanism becomes low. Here we discuss the climates of Earth-like planets in which the carbonate-silicate geochemical cycle is working, with focusing particularly on insolation and the CO{sub 2} degassing rate. The climate of Earth-like planets within the HZ can be classified into three climate modes (hot, warm, and snowball climate modes). We found that the conditions for the existence of liquid water should be largely restricted even when the planet is orbiting within the HZ and the carbonate-silicate geochemical cycle is working. We show that these conditions should depend strongly on the rate of CO{sub 2} degassing via volcanism. It is, therefore, suggested that thermal evolution of the planetary interiors will be a controlling factor for Earth-like planets to have liquid water on their surface.

  19. Outer Planets

    NASA Video Gallery

    Did you know that through NASA’s various satellite missions we have learned more about these planetary bodies in recent years than we knew collectively since we started to study our planets? Throu...

  20. [Extrasolar terrestrial planets and possibility of extraterrestrial life].

    PubMed

    Ida, Shigeru

    2003-12-01

    Recent development of research on extrasolar planets are reviewed. About 120 extrasolar Jupiter-mass planets have been discovered through the observation of Doppler shift in the light of their host stars that is caused by acceleration due to planet orbital motions. Although the extrasolar planets so far observed may be limited to gas giant planets and their orbits differ from those of giant planets in our Solar system (Jupiter and Saturn), the theoretically predicted probability of existence of extrasolar terrestrial planets that can have liquid water ocean on their surface is comparable to that of detectable gas giant planets. Based on the number of extrasolar gas giants detected so far, about 100 life-sustainable planets may exist within a range of 200 light years. Indirect observation of extrasolar terrestrial planets would be done with space telescopes within several years and direct one may be done within 20 years. The latter can detect biomarkers on these planets as well.

  1. Microlensing Planets

    NASA Astrophysics Data System (ADS)

    Gould, Andrew

    The theory and practice of microlensing planet searches is developed in a systematic way, from an elementary treatment of the deflection of light by a massive body to a thorough discussion of the most recent results. The main concepts of planetary microlensing, including microlensing events, finite-source effects, and microlens parallax, are first introduced within the simpler context of point-lens events. These ideas are then applied to binary (and hence planetary) lenses and are integrated with concepts specific to binaries, including caustic topologies, orbital motion, and degeneracies, with an emphasis on analytic understanding. The most important results from microlensing planet searches are then reviewed, with emphasis both on understanding the historical process of discovery and the means by which scientific conclusions were drawn from light-curve analysis. Finally, the future prospects of microlensing planets searches are critically evaluated. Citations to original works provide the reader with multiple entry points into the literature.

  2. Stability of Liquid Water on a Land Planet: Wider Habitable Zone for a Less Water Planet than an Aqua Planet

    NASA Astrophysics Data System (ADS)

    Abe, Y.; Abe-Ouchi, A.; Zahnle, K. J.

    2009-12-01

    Most of the previous studies on the habitable zone implicitly assume an ocean-covered 'aqua' planet that has a large amount of liquid water like the present Earth. However, there is a possibility of a habitable 'land' planet that is covered by vast dry desert but has locally abundant water. The land planet state is expected when the fraction of water covered areas is less than about half of surface. Ancient Mars might be in such a state. The conditions for the existence of liquid water can be different for a less water land planet from that of an aqua planet, because both the ice-albedo feedback, which causes the complete freezing, and the runaway greenhouse, which causes the complete evaporation, are enhanced by abundant water. Here, we investigated the condition for the solar flux that cause the complete freezing or evaporation of liquid water on a land planet using a general circulation model. We use a general circulation model, CCSR/NIES AGCM5.4g, which have been developed for the Earth’s climate modeling by the Centre for Climate System Research, University of Tokyo and the National Institute for Environmental Research. To compare a land planet with an aqua planet, we consider an Earth-sized planet without topography with 1 bar air atmosphere on a circular orbit. The distribution of water on a land planet is completely determined by the atmospheric circulation. On a land planet, complete freezing and complete evaporation of water occurred at the 77% and 170% of the present Earth's solar flux, respectively. On the other hand, complete freezing and evaporation of an aqua planet occurs at 90% and about 130%, respectively. Thus, a land planet shows stronger resistance to both the complete freezing and evaporation of liquid water than an aqua planet. The stability field of liquid water is quite wide on a land planet compared with that of an aqua planet. In addition, escape flux of water from a land planet is very small because of dry upper atmosphere. It suggests

  3. Stability of Liquid Water on a Land Planet: Wider Habitable Zone for a Less Water Planet than an Aqua Planet

    NASA Astrophysics Data System (ADS)

    Abe, Y.; Abe-Ouchi, A.

    2005-12-01

    Most of the previous studies on the habitable zone implicitly assume an ocean-covered 'aqua' planet that has a large amount of liquid water like the present Earth. However, there is a possibility of a habitable 'land' planet that is covered by vast dry desert but has locally abundant water. Ancient Mars might be in such a state. The conditions for the stability of liquid water can be different for a less water land planet from that of an aqua planet, because both the ice-albedo feedback, which causes the complete freezing, and the runaway greenhouse, which causes the complete evaporation, are enhanced by abundant water. Here, we investigated the condition for the solar flux that cause the complete freezing or evaporation of liquid water on a land planet using a general circulation model. We use a general circulation model, CCSR/NIES AGCM5.4g, which have been developed for the Earth's climate modeling by the Centre for Climate System Research, University of Tokyo and the National Institute for Environmental Research. To compare a land planet with an aqua planet, we consider an Earth-sized planet without topography with 1 bar air atmosphere on a circular orbit. The distribution of water on a land planet is completely determined by the atmospheric circulation. On a land planet, complete freezing and complete evaporation of water occurred at the 77% and 170% of the present Earth's solar flux, respectively. On the other hand, complete freezing and evaporation of an aqua planet occurs at 90% and about 130%, respectively. The absolute values of the criteria depends on the abundance of the greenhouse gases. However, the relative values between the land and aqua planets would not be changed. Thus, a land planet shows stronger resistance to both the complete freezing and evaporation of liquid water than an aqua planet. The stability field of liquid water is quite wide on a land planet compared with that of an aqua planet. It suggests that a water rich aqua planet may not be

  4. Mission to planet earth

    SciTech Connect

    Baker, D.J.

    1988-07-01

    Plans for environmental monitoring using remote-sensing satellites in the era of the International Space Station are reviewed. The role of international cooperation is stressed, considering the present Landsat, SPOT, and Marine Observation Satellite programs; ERS-1 and Topex/Poseidon; and plans for the Italian Lageos-2, the Indian Remote Sensing Satellite, and the Japanese Advanced Earth Observation Satellite. The NASA Mission to Planet Earth proposal calls for four polar-orbit and five GEO platforms (five NASA, two ESA, and two NASDA), to be in place by the year 2000, as well as dedicated spacecraft of the Earth System Explorer series in the 1990s. Payloads will monitor the geomagnetic field, atmospheric temperature and water vapor, O3 and aerosols, outgoing radiation, precipitation, sea-surface temperature, sea ice, ocean chlorophyll, surface winds, wave height, ocean circulation, snow cover, land use, vegetation, crops, volcanic activity, and the hydrologic cycle.

  5. A Planet Detection Tutorial and Simulator

    NASA Technical Reports Server (NTRS)

    Knoch, David; DeVincenzi, Donald (Technical Monitor)

    2001-01-01

    Detection of extra-solar planets has been a very popular topic with the general public for years. Considerable media coverage of recent detections (currently at about 50) has only heightened the interest in the topic. School children are particularly interested in learning about recent astronomical discoveries. Scientists have the knowledge and responsibility to present this information in both an understandable and interesting format. Most classrooms and homes are now connected to the internet, which can be utilized to provide more than a traditional 'flat' presentation. An interactive software package on planet detection has been developed. The major topics include: "1996 - The Break Through Year In Planet Detection"; "What Determines If A Planet Is Habitable?"; "How Can We Find Other Planets (Search Methods)"; "All About the Kepler Mission: How To Find Terrestrial Planets"; and "A Planet Detection Simulator". Using the simulator, the student records simulated observations and then analyzes and interprets the data within the program. One can determine the orbit and planet size, the planet's temperature and surface gravity, and finally determine if the planet is habitable. Originally developed for the Macintosh, a web based browser version is being developed.

  6. The Popular Culture Explosion.

    ERIC Educational Resources Information Center

    Browne, Ray B.; Madden, David

    Popular culture is defined here as anything produced by and/or dissembled by the mass media or mass production or transportation, either directly or indirectly, and that reaches the majority of the people. This sampler from mass magazines, intended for use in the study of popular culture, includes fiction from "Playboy"; articles on cars, Johnny…

  7. Ocean Acidification

    NASA Astrophysics Data System (ADS)

    Iglesias-Rodriguez, Maria Debora

    The oceans play a central role in the maintenance of life on Earth. Oceans provide extensive ecosystems for marine animals and plants covering two-thirds of the Earth's surface, are essential sources of food, economic activity, and biodiversity, and are central to the global biogeochemical cycles. The oceans are the largest reservoir of carbon in the Planet, and absorb approximately one-third of the carbon emissions that are released to the Earth's atmosphere as a result of human activities. Since the beginning of industrialization, humans have been responsible for the increase in one greenhouse gas, carbon dioxide (CO2), from approximately 280 parts per million (ppm) at the end of the nineteenth century to the current levels of 390ppm. As well as affecting the surface ocean pH, and the organisms living at the ocean surface, these increases in CO2 are causing global mean surface temperatures to rise.

  8. Extrasolar Planets and Prospects for Terrestrial Planets

    NASA Astrophysics Data System (ADS)

    Marcy, Geoffrey W.; Butler, R. Paul; Vogt, Steven S.; Fischer, Debra A.

    2004-06-01

    Examination of ˜2000 sun--like stars has revealed 97 planets (as of 2002 Nov), all residing within our Milky Way Galaxy and within ˜200 light years of our Solar System. They have masses between 0.1 and 10 times that of Jupiter, and orbital sizes of 0.05--5 AU. Thus planets occupy the entire detectable domain of mass and orbits. News &summaries about extrasolar planets are provided at: http://exoplanets.org. These planets were all discovered by the wobble of the host stars, induced gravitationally by the planets, causing a periodicity in the measured Doppler effect of the starlight. Earth--mass planets remain undetectable, but space--based missions such as Kepler, COROT and SIM may provide detections of terrestrial planets within the next decade. The number of planets increases with decreasing planet mass, indicating that nature makes more small planets than jupiter--mass planets. Extrapolation, though speculative, bodes well for an even larger number of earth--mass planets. These observations and the theory of planet formation suggests that single sun--like stars commonly harbor earth--sized rocky planets, as yet undetectable. The number of planets increases with increasing orbital distance from the host star, and most known planets reside in non--circular orbits. Many known planets reside in the habitable zone (albeit being gas giants) and most newly discovered planets orbit beyond 1 AU from their star. A population of Jupiter--like planets may reside at 5--10 AU from stars, not easily detectable at present. The sun--like star 55 Cancri harbors a planet of 4--10 Jupiter masses orbiting at 5.5 AU in a low eccentricity orbit, the first analog of our Jupiter, albeit with two large planets orbiting inward. To date, 10 multiple--planet systems have been discovered, with four revealing gravitational interactions between the planets in the form of resonances. GJ 876 has two planets with periods of 1 and 2 months. Other planetary systems are ``hierarchical'', consisting

  9. Barnard’s Star: Planets or Pretense

    NASA Astrophysics Data System (ADS)

    Bartlett, Jennifer L.; Ianna, P. A.

    2014-01-01

    Barnard’s Star remains popular with planet hunters because it is not only an extremely near, high proper motion star, but also the object of early planet-detection claims. In 1963, van de Kamp explained perturbations in its proper motion by the presence of a planet. In 1969, he produced another single-planet solution and a two-planet solution to the astrometric wobbles detected. At least 19 studies have failed to confirm his results using a range of techniques, including radial velocity, direct imaging, and speckle interferometry. However, most of them lacked the sensitivity to detect the planets he described, including astrometric studies at the McCormick and Naval Observatories. However, radial-velocity monitoring of Barnard’s Star at Lick and Keck Observatories from 1987 through 2012 appears to have ruled out such planets. Based upon observations made at the Sproul Observatory between 1916 and 1962, van de Kamp claimed that Barnard’s Star had a planet with about 1.6 times the mass of Jupiter and an orbital period of 24 years. After accounting for instrumentation effects that might have been partially responsible for his initial results, he continued to assert that this red dwarf had two planets. In his 1982 analysis of ~20,000 exposures collected between 1938 and 1981, he calculated that two planets with 0.7- and 0.5-Jupiter masses in 12- and 20-year orbits, respectively, orbited the second-closest stellar system to our own. Starting in 1995, the dramatic successes of radial velocity searches for extrasolar planets drove van de Kamp’s unsubstantiated claims from popular consciousness. Although many low-mass stellar companions were discovered through astrometry, the technique has been less successful for planets: “The Extrasolar Planets Encyclopaedia” identifies one such discovery out of the 997 planets listed on 2013 September 23. Although Barnard’s Star has lost its pretensions to hosting the first extrasolar planets known, its intrinsic

  10. Exploring Planet Sizes

    NASA Video Gallery

    This lesson combines a series of activities to compare models of the size of Earth to other planets and the distances to other planets. Activities highlight space missions to other planets in our s...

  11. No Pseudosynchronous Rotation for Terrestrial Planets and Moons

    DTIC Science & Technology

    2013-02-10

    reserved. Printed in the U.S.A. NO PSEUDOSYNCHRONOUS ROTATION FOR TERRESTRIAL PLANETS AND MOONS Valeri V. Makarov and Michael Efroimsky US Naval...January 21 ABSTRACT We re-examine the popular belief that a telluric planet or a satellite on an eccentric orbit can, outside a spin–orbit resonance...development demonstrates that there exist no stable equilibrium states for solid planets and moons, other than spin–orbit resonances. Key words: celestial

  12. Exploring the Living Planet with David Attenborough.

    ERIC Educational Resources Information Center

    Burgess, Jacquelin; Unwin, David

    1984-01-01

    In this interview David Attenborough, the celebrated natural history film maker and writer, talks about his highly successful television series, "The Living Planet." Devoted to the exposition of the world's ecosystems, the film represents a significant example of popular geographic education. (RM)

  13. PLANET-PLANET SCATTERING IN PLANETESIMAL DISKS

    SciTech Connect

    Raymond, Sean N.; Armitage, Philip J.; Gorelick, Noel

    2009-07-10

    We study the final architecture of planetary systems that evolve under the combined effects of planet-planet and planetesimal scattering. Using N-body simulations we investigate the dynamics of marginally unstable systems of gas and ice giants both in isolation and when the planets form interior to a planetesimal belt. The unstable isolated systems evolve under planet-planet scattering to yield an eccentricity distribution that matches that observed for extrasolar planets. When planetesimals are included the outcome depends upon the total mass of the planets. For M {sub tot} {approx}> 1 M{sub J} the final eccentricity distribution remains broad, whereas for M {sub tot} {approx}< 1 M{sub J} a combination of divergent orbital evolution and recircularization of scattered planets results in a preponderance of nearly circular final orbits. We also study the fate of marginally stable multiple planet systems in the presence of planetesimal disks, and find that for high planet masses the majority of such systems evolve into resonance. A significant fraction leads to resonant chains that are planetary analogs of Jupiter's Galilean satellites. We predict that a transition from eccentric to near-circular orbits will be observed once extrasolar planet surveys detect sub-Jovian mass planets at orbital radii of a {approx_equal} 5-10 AU.

  14. Popular misconceptions: agricultural biotechnology.

    PubMed

    McHughen, Alan; Wager, Robert

    2010-12-31

    Agricultural biotechnology, especially genetic engineering or genetic modification (GM), is a topic of considerable controversy worldwide. The public debate is fraught with polarized views and opinions, some are held with religious zeal. Unfortunately, it is also marked with much ignorance and misinformation. Here we explore some popular misconceptions encountered in the public debate.

  15. Popularity in Wonderland.

    ERIC Educational Resources Information Center

    Nist, J.S.

    Specialists in the field of children's literature, who publish research and decide on awards for individual books, should give serious study to what children themselves choose to read. Among the children's books that were not originally awarded top honors by critics but that have proved extremely popular with children are the Oz books by L. Frank…

  16. Most Popular Campus

    ERIC Educational Resources Information Center

    Montgomery, Roger

    1973-01-01

    Foothill College owes its tremendous popularity to the fact that it neither fits into the tradition of the modern movement of architectural art, with its in-group language of heroic forms constructed in brute concrete, nor the more esoteric world that sees high art in commercial strip development and A & P parking lots. (Author)

  17. Dance of the Planets

    ERIC Educational Resources Information Center

    Riddle, Bob

    2005-01-01

    As students continue their monthly plotting of the planets along the ecliptic they should start to notice differences between inner and outer planet orbital motions, and their relative position or separation from the Sun. Both inner and outer planets have direct eastward motion, as well as retrograde motion. Inner planets Mercury and Venus,…

  18. Elites and popular nationalism.

    PubMed

    Whitmeyer, Joseph M

    2002-09-01

    Much current theory concerning nationalism holds that elites commonly create or cause popular nationalism. In part, that thesis may be due to an overwhelming emphasis in research on nationalism on positive cases: cases where nationalism has appeared, ignoring cases where it has not. In this article, I challenge the thesis by showing numerous historical cases in which elites have promoted nationalisms that ordinary people have not adopted, or in which ordinary people have adopted a nationalism before it was taken up by elites. Even if elites do not create popular nationalism, however, they can and do shape its expression in a variety of ways, such as organizing it, providing relevant information, or providing opportunity or incentive for it. I show this through historical examples.

  19. Popular perceptions of Galileo

    NASA Astrophysics Data System (ADS)

    Sobel, Dava

    2010-01-01

    Among the most persistent popular misperceptions of Galileo is the image of an irreligious scientist who opposed the Catholic Church and was therefore convicted of heresy-was even excommunicated, according to some accounts, and denied Christian burial. In fact, Galileo considered himself a good Catholic. He accepted the Bible as the true word of God on matters pertaining to salvation, but insisted Scripture did not teach astronomy. Emboldened by his discovery of the Medicean Moons, he took a stand on Biblical exegesis that has since become the official Church position.

  20. The origin of life from primordial planets

    NASA Astrophysics Data System (ADS)

    Gibson, Carl H.; Schild, Rudolph E.; Wickramasinghe, N. Chandra

    2011-04-01

    The origin of life and the origin of the Universe are among the most important problems of science and they might be inextricably linked. Hydro-gravitational-dynamics cosmology predicts hydrogen-helium gas planets in clumps as the dark matter of galaxies, with millions of planets per star. This unexpected prediction is supported by quasar microlensing of a galaxy and a flood of new data from space telescopes. Supernovae from stellar over-accretion of planets produce the chemicals (C, N, O, P, etc.) and abundant liquid-water domains required for first life and the means for wide scattering of life prototypes. Life originated following the plasma-to-gas transition between 2 and 20 Myr after the big bang, while planetary core oceans were between critical and freezing temperatures, and interchanges of material between planets constituted essentially a cosmological primordial soup. Images from optical, radio and infrared space telescopes suggest life on Earth was neither first nor inevitable.

  1. Ocean Robotic Networks

    SciTech Connect

    Schofield, Oscar

    2012-05-23

    We live on an ocean planet which is central to regulating the Earth’s climate and human society. Despite the importance of understanding the processes operating in the ocean, it remains chronically undersampled due to the harsh operating conditions. This is problematic given the limited long term information available about how the ocean is changing. The changes include rising sea level, declining sea ice, ocean acidification, and the decline of mega fauna. While the changes are daunting, oceanography is in the midst of a technical revolution with the expansion of numerical modeling techniques, combined with ocean robotics. Operating together, these systems represent a new generation of ocean observatories. I will review the evolution of these ocean observatories and provide a few case examples of the science that they enable, spanning from the waters offshore New Jersey to the remote waters of the Southern Ocean.

  2. Kepler Planet Formation

    NASA Technical Reports Server (NTRS)

    Lissauer, Jack J.

    2015-01-01

    Kepler has vastly increased our knowledge of planets and planetary systems located close to stars. The new data shows surprising results for planetary abundances, planetary spacings and the distribution of planets on a mass-radius diagram. The implications of these results for theories of planet formation will be discussed.

  3. Terrestrial Planets: Comparative Planetology

    NASA Technical Reports Server (NTRS)

    1985-01-01

    Papers were presented at the 47th Annual Meteoritical Society Meeting on the Comparative planetology of Terrestrial Planets. Subject matter explored concerning terrestrial planets includes: interrelationships among planets; plaentary evolution; planetary structure; planetary composition; planetary Atmospheres; noble gases in meteorites; and planetary magnetic fields.

  4. Nebulous networks: Virginia Woolf and popular astronomy

    NASA Astrophysics Data System (ADS)

    Henry, Holly Grace

    This study investigates Virginia Woolf's fascination with advances in astronomy and telescopic technologies of the 1920s and 30s. Grounded in the cultural studies of science, and the work of theorists such as Donna Haraway and Bruno Latour, the dissertation reconstructs the complex interconnections between Woolf's fiction and prose writing and an explosive popular interest in astronomy and cosmology. Woolf's aesthetic and political practices were shaped by emerging visualization technologies ranging from astronomical telescopes to the hand-held camera. While her writing provides a focus for this investigation, the dissertation offers close readings of fiction and essays by multiple British authors and science writers in the context of these converging phenomena. As a result of glimpsing tiny worlds through her own telescope, Virginia Woolf formulated a global aesthetic and a global politics. Gazing at the moon and stars reminded her that earth is a planet in space, and that earth's inhabitants must rely on this small, fragile globe for their future survival. The opening chapter establishes the cultural context for the study. In 1923, the American astronomer Edwin Hubble determined that the Andromeda galaxy was located far beyond the limits of the Milky Way, then believed to comprise the entire universe. Hubble's radical reconfiguration of the universe contributed to a pervasive sense, in the modern period, of a decentering and re-scaling of humans in the universe. In the chapters that follow, the dissertation offers readings of Woolf's novels and short fiction in relation to her fascination with astronomy and explores how the wildly popular British cosmologist and science writer, Sir James jeans, had a shaping effect on popular culture and on Woolf's narrative practices and pacifist politics. Despite his oblique connections to what became Bloomsbury, jeans and his popular science texts were to play a considerable role in Woolf's formulation of a global aesthetic.

  5. Comparative phylogeography of the ocean planet

    PubMed Central

    Bowen, Brian W.; Gaither, Michelle R.; DiBattista, Joseph D.; Iacchei, Matthew; Andrews, Kimberly R.; Grant, W. Stewart; Toonen, Robert J.; Briggs, John C.

    2016-01-01

    Understanding how geography, oceanography, and climate have ultimately shaped marine biodiversity requires aligning the distributions of genetic diversity across multiple taxa. Here, we examine phylogeographic partitions in the sea against a backdrop of biogeographic provinces defined by taxonomy, endemism, and species composition. The taxonomic identities used to define biogeographic provinces are routinely accompanied by diagnostic genetic differences between sister species, indicating interspecific concordance between biogeography and phylogeography. In cases where individual species are distributed across two or more biogeographic provinces, shifts in genotype frequencies often align with biogeographic boundaries, providing intraspecific concordance between biogeography and phylogeography. Here, we provide examples of comparative phylogeography from (i) tropical seas that host the highest marine biodiversity, (ii) temperate seas with high productivity but volatile coastlines, (iii) migratory marine fauna, and (iv) plankton that are the most abundant eukaryotes on earth. Tropical and temperate zones both show impacts of glacial cycles, the former primarily through changing sea levels, and the latter through coastal habitat disruption. The general concordance between biogeography and phylogeography indicates that the population-level genetic divergences observed between provinces are a starting point for macroevolutionary divergences between species. However, isolation between provinces does not account for all marine biodiversity; the remainder arises through alternative pathways, such as ecological speciation and parapatric (semiisolated) divergences within provinces and biodiversity hotspots. PMID:27432963

  6. Comparative phylogeography of the ocean planet.

    PubMed

    Bowen, Brian W; Gaither, Michelle R; DiBattista, Joseph D; Iacchei, Matthew; Andrews, Kimberly R; Grant, W Stewart; Toonen, Robert J; Briggs, John C

    2016-07-19

    Understanding how geography, oceanography, and climate have ultimately shaped marine biodiversity requires aligning the distributions of genetic diversity across multiple taxa. Here, we examine phylogeographic partitions in the sea against a backdrop of biogeographic provinces defined by taxonomy, endemism, and species composition. The taxonomic identities used to define biogeographic provinces are routinely accompanied by diagnostic genetic differences between sister species, indicating interspecific concordance between biogeography and phylogeography. In cases where individual species are distributed across two or more biogeographic provinces, shifts in genotype frequencies often align with biogeographic boundaries, providing intraspecific concordance between biogeography and phylogeography. Here, we provide examples of comparative phylogeography from (i) tropical seas that host the highest marine biodiversity, (ii) temperate seas with high productivity but volatile coastlines, (iii) migratory marine fauna, and (iv) plankton that are the most abundant eukaryotes on earth. Tropical and temperate zones both show impacts of glacial cycles, the former primarily through changing sea levels, and the latter through coastal habitat disruption. The general concordance between biogeography and phylogeography indicates that the population-level genetic divergences observed between provinces are a starting point for macroevolutionary divergences between species. However, isolation between provinces does not account for all marine biodiversity; the remainder arises through alternative pathways, such as ecological speciation and parapatric (semiisolated) divergences within provinces and biodiversity hotspots.

  7. Extrasolar planets: constraints for planet formation models.

    PubMed

    Santos, Nuno C; Benz, Willy; Mayor, Michel

    2005-10-14

    Since 1995, more than 150 extrasolar planets have been discovered, most of them in orbits quite different from those of the giant planets in our own solar system. The number of discovered extrasolar planets demonstrates that planetary systems are common but also that they may possess a large variety of properties. As the number of detections grows, statistical studies of the properties of exoplanets and their host stars can be conducted to unravel some of the key physical and chemical processes leading to the formation of planetary systems.

  8. Popular weight reduction diets.

    PubMed

    Volpe, Stella Lucia

    2006-01-01

    The percentage of people who are overweight and obese has increased tremendously over the last 30 years. It has become a worldwide epidemic. This is evident by the number of children are being diagnosed with a body mass index >85th percentile, and the number of children begin diagnosed with type 2 diabetes mellitus, a disease previously reserved for adults. The weight loss industry has also gained from this epidemic; it is a billion dollar industry. People pay large sums of money on diet pills, remedies, and books, with the hope of losing weight permanently. Despite these efforts, the number of individuals who are overweight or obese continues to increase. Obesity is a complex, multifactorial disorder. It would be impossible to address all aspects of diet, exercise, and weight loss in this review. Therefore, this article will review popular weight loss diets, with particular attention given to comparing low fat diets with low carbohydrate diets. In addition, the role that the environment plays on both diet and exercise and how they impact obesity will be addressed. Finally, the National Weight Control Registry will be discussed.

  9. Planet Demographics from Transits

    NASA Astrophysics Data System (ADS)

    Howard, Andrew

    2015-08-01

    From the demographics of planets detected by the Kepler mission, we have learned that there exists approximately one planet per star for planets larger than Earth orbiting inside of 1 AU. We have also learned the relative occurrence of these planets as a function of their orbital periods, sizes, and host star masses and metallicities. In this talk I will review the key statistical findings that the planet size distribution peaks in the range 1-3 times Earth-size, the orbital period distribution is characterized by a power-law cut off at short periods, small planets are more prevalent around small stars, and that approximately 20% of Sun-like stars hosts a planet 1-2 times Earth-size in a habitable zone. Looking forward, I will describe analysis of photometry from the K2 mission that is yielding initial planet discoveries and offering the opportunity to measure planet occurrence in widely separated regions of the galaxy. Finally, I will also discuss recent techniques to discover transiting planets in space-based photometry and to infer planet population properties from the ensemble of detected and non-detected transit signals.

  10. DETECTING VOLCANISM ON EXTRASOLAR PLANETS

    SciTech Connect

    Kaltenegger, L.; Sasselov, D. D.; Henning, W. G.

    2010-11-15

    The search for extrasolar rocky planets has already found the first transiting rocky super-Earth, Corot 7b, with a surface temperature that allows for magma oceans. Here, we investigate whether we could distinguish rocky planets with recent major volcanism by remote observation. We develop a model for volcanic eruptions on an Earth-like exoplanet based on the present-day Earth and derive the observable features in emergent and transmission spectra for multiple scenarios of gas distribution and cloud cover. We calculate the observation time needed to detect explosive volcanism on exoplanets in primary as well as secondary eclipse and discuss the likelihood of observing volcanism on transiting Earth-sized to super-Earth-sized exoplanets. We find that sulfur dioxide from large explosive eruptions does present a spectral signal that is remotely detectable especially for secondary eclipse measurements around the closest stars and ground-based telescopes, and report the frequency and magnitude of the expected signatures. The transit probability of a planet in the habitable zone decreases with distance from the host star, making small, nearby host stars the best targets.

  11. Wave of a Planet

    NASA Technical Reports Server (NTRS)

    2007-01-01

    This plot tells astronomers that a fifth planet is in orbit around the star 55 Cancri, making the star the record-holder for hosting the most known exoplanets.

    As planets circle around their stars, they cause the stars to wobble back and forth in a regular pattern. By looking for this motion in a star, scientists can find planets that can't be seen with telescopes.

    The wobble caused by the fifth planet discovered around 55 Cancri is represented here by the sinuous line in blue. The actual data points are yellow and error bars are the lines above and below the yellow dots. The cycle of the wobble indicates that the planet circles around its star about every 260 days. The amplitude of the wobble indicates that the planet is a giant at least 45 times the mass of Earth.

    The wobbles caused by the other four planets has been removed from this plot, to reveal that caused by the fifth. The departure from a perfect sine wave suggests the planet's orbit is not perfectly circular.

    Because 55 Cancri has multiple planets, the star had to be observed for a long time before astronomers could find and confirm its fifth planet. These data were collected over a period of 18 years using both the Lick Observatory near San Jose, Calif., and the W.M. Keck Observatory in Hawaii.

  12. Juggling Popularity and Quality: Literary Excellence vs. Popular Culture.

    ERIC Educational Resources Information Center

    Genco, Barbara A.; And Others

    1991-01-01

    Three librarians--Barbara A. Genco from Brooklyn, New York; Eleanor K. MacDonald from Beverly Hills, California; and Betsy Hearne from Chicago, Illinois--share their perspectives on where popular literature should fit into library material selection and children's reading diets. Popular literature is defined as primarily that which has first…

  13. Tomorrow's Forecast: Oceans and Weather.

    ERIC Educational Resources Information Center

    Smigielski, Alan

    1995-01-01

    This issue of "Art to Zoo" focuses on weather and climate and is tied to the traveling exhibition Ocean Planet from the Smithsonian's National Museum of Natural History. The lessons encourage students to think about the profound influence the oceans have on planetary climate and life on earth. Sections of the lesson plan include: (1)…

  14. Rethinking Popular Culture and Media

    ERIC Educational Resources Information Center

    Marshall, Elizabeth, Ed.; Sensoy, Ozlem, Ed.

    2011-01-01

    "Rethinking Popular Culture and Media" is a provocative collection of articles that begins with the idea that the "popular" in classrooms and in the everyday lives of teachers and students is fundamentally political. This anthology includes outstanding articles by elementary and secondary public school teachers, scholars, and activists who…

  15. New Dimensions in Popular Culture.

    ERIC Educational Resources Information Center

    Nye, Russel B., Ed.

    This document contains fifteen essays which study some of the didactic, moralistic literature which was popular in nineteenth century America, and speculate about the culture from which the literature evolved. The essays include "Millions of Moral Little Books: Sunday School Books in Their Popular Context"; "Nineteenth Century Gift Books: A…

  16. Terrestrial planet formation

    PubMed Central

    Righter, K.; O’Brien, D. P.

    2011-01-01

    Advances in our understanding of terrestrial planet formation have come from a multidisciplinary approach. Studies of the ages and compositions of primitive meteorites with compositions similar to the Sun have helped to constrain the nature of the building blocks of planets. This information helps to guide numerical models for the three stages of planet formation from dust to planetesimals (∼106 y), followed by planetesimals to embryos (lunar to Mars-sized objects; few × 106 y), and finally embryos to planets (107–108 y). Defining the role of turbulence in the early nebula is a key to understanding the growth of solids larger than meter size. The initiation of runaway growth of embryos from planetesimals ultimately leads to the growth of large terrestrial planets via large impacts. Dynamical models can produce inner Solar System configurations that closely resemble our Solar System, especially when the orbital effects of large planets (Jupiter and Saturn) and damping mechanisms, such as gas drag, are included. Experimental studies of terrestrial planet interiors provide additional constraints on the conditions of differentiation and, therefore, origin. A more complete understanding of terrestrial planet formation might be possible via a combination of chemical and physical modeling, as well as obtaining samples and new geophysical data from other planets (Venus, Mars, or Mercury) and asteroids. PMID:21709256

  17. Planet Formation - Overview

    NASA Technical Reports Server (NTRS)

    Lissauer, Jack J.

    2005-01-01

    Modern theories of star and planet formation are based upon observations of planets and smaller bodies within our own Solar System, exoplanets &round normal stars and of young stars and their environments. Terrestrial planets are believed to grow via pairwise accretion until the spacing of planetary orbits becomes large enough that the configuration is stable for the age of the system. Giant planets begin their growth as do terrestrial planets, but they become massive enough that they are able to accumulate substantial amounts of gas before the protoplanetary disk dissipates. These models predict that rocky planets should form in orbit about most single stars. It is uncertain whether or not gas giant planet formation is common, because most protoplanetary disks may dissipate before solid planetary cores can grow large enough to gravitationally trap substantial quantities of gas. A potential hazard to planetary systems is radial decay of planetary orbits resulting from interactions with material within the disk. Planets more massive than Earth have the potential to decay the fastest, and may be able to sweep up smaller planets in their path.

  18. Detecting Extrasolar Planets Directly

    NASA Astrophysics Data System (ADS)

    Guenther, E. W.; Neuhäuser, R.; Huélamo, N.; Ott, T.; Brandner, W.; Alves, J.; Comerón, F.; Eckart, A.; Hatzes, A.

    Up to now, all extrasolar planets have been found by means of indirect methods. Direct detection of planets orbiting even the nearest stars seems at first glance to be impossible with present day equipment, because of the enormous difference in brightness between the star and the planet, and the small angular separation between them. However, young planets which are still in the contraction phase of evolution are comparatively bright in the infrared, and since many of the extrasolar planets detected have excentric orbits, where they are most of the time at a relatively large distance from the stars, the prospect of detecting young planets directly is much better. In fact, it is principle be possible to detect an extrasolar giant planet, if the planet is younger than 100 millon years, and if the distance is less than 100 pc. Three years ago we thus have embarked on a survey to observe more than one-hundred young, nearby stars in the near infrared. In this talk, we will review the status of the survey. In order to find out whether these stars have additionally a planet at a small distance from the star, we also carried out sensitive radial velocity observation of a subsample using an iodine-cell and the Echelle spectrograph of the Alfred-Jensch Telescope in Tautenburg.

  19. Terrestrial planet formation.

    PubMed

    Righter, K; O'Brien, D P

    2011-11-29

    Advances in our understanding of terrestrial planet formation have come from a multidisciplinary approach. Studies of the ages and compositions of primitive meteorites with compositions similar to the Sun have helped to constrain the nature of the building blocks of planets. This information helps to guide numerical models for the three stages of planet formation from dust to planetesimals (~10(6) y), followed by planetesimals to embryos (lunar to Mars-sized objects; few 10(6) y), and finally embryos to planets (10(7)-10(8) y). Defining the role of turbulence in the early nebula is a key to understanding the growth of solids larger than meter size. The initiation of runaway growth of embryos from planetesimals ultimately leads to the growth of large terrestrial planets via large impacts. Dynamical models can produce inner Solar System configurations that closely resemble our Solar System, especially when the orbital effects of large planets (Jupiter and Saturn) and damping mechanisms, such as gas drag, are included. Experimental studies of terrestrial planet interiors provide additional constraints on the conditions of differentiation and, therefore, origin. A more complete understanding of terrestrial planet formation might be possible via a combination of chemical and physical modeling, as well as obtaining samples and new geophysical data from other planets (Venus, Mars, or Mercury) and asteroids.

  20. Satisfaction Analysis of Experiential Learning-Based Popular Science Education

    ERIC Educational Resources Information Center

    Dzan, Wei-Yuan; Tsai, Huei-Yin; Lou, Shi-Jer; Shih, Ru-Chu

    2015-01-01

    This study employed Kolb's experiential learning model-specific experiences, observations of reflections, abstract conceptualization, and experiment-action in activities to serve as the theoretical basis for popular science education planning. It designed the six activity themes of "Knowledge of the Ocean, Easy to Know, See the Large from the…

  1. A Maximum Radius for Habitable Planets.

    PubMed

    Alibert, Yann

    2015-09-01

    We compute the maximum radius a planet can have in order to fulfill two constraints that are likely necessary conditions for habitability: 1- surface temperature and pressure compatible with the existence of liquid water, and 2- no ice layer at the bottom of a putative global ocean, that would prevent the operation of the geologic carbon cycle to operate. We demonstrate that, above a given radius, these two constraints cannot be met: in the Super-Earth mass range (1-12 Mearth), the overall maximum that a planet can have varies between 1.8 and 2.3 Rearth. This radius is reduced when considering planets with higher Fe/Si ratios, and taking into account irradiation effects on the structure of the gas envelope.

  2. Name That Planet!

    ERIC Educational Resources Information Center

    Beck, Judy; Rust, Cindy

    2002-01-01

    Presents an activity in which students in groups explore one planet in the solar system and present their findings to the whole class. Focuses on the planet's location in the solar system, geological features, rate of revolutions, and calendar year. (YDS)

  3. March of the Planets

    ERIC Educational Resources Information Center

    Thompson, Bruce

    2007-01-01

    The motion of the planets in their orbits can be demonstrated to students by using planetarium software programs. These allow time to be sped up so that the relative motions are readily observed. However, it is also valuable to have the students understand the real speed of the planets in their orbits. This paper describes an exercise that gives…

  4. Planets in Motion

    ERIC Educational Resources Information Center

    Riddle, Bob

    2005-01-01

    All the planets in the solar system revolve around the Sun in the same direction, clockwise when viewed from above the North Pole. This is referred to as direct motion. From the perspective on the Earth's surface, the planets travel east across the sky in relation to the background of stars. The Sun also moves eastward daily, but this is an…

  5. Models for ecological models: Ocean primary productivity

    USGS Publications Warehouse

    Wikle, Christopher K.; Leeds, William B.; Hooten, Mevin B.

    2016-01-01

    The ocean accounts for more than 70% of planet Earth's surface, and it processes are critically important to marine and terrestrial life.  Ocean ecosystems are strongly dependent on the physical state of the ocean (e.g., transports, mixing, upwelling, runoff, and ice dynamics(.  As an example, consider the Coastal Gulf of Alaska (CGOA) region.

  6. Comparative Climatology of Terrestrial Planets

    NASA Astrophysics Data System (ADS)

    Mackwell, Stephen J.; Simon-Miller, Amy A.; Harder, Jerald W.; Bullock, Mark A.

    stimulate further research on this critical subject. The study of climate involves much more than understanding atmospheric processes. This subtlety is particularly appreciated for Earth, where chemical cycles, geology, ocean influences, and biology are considered in most climate models. In Part IV, Surface and Interior, we look at the role that geochemical cycles, volcanism, and interior mantle processes play in the stability and evolution of terrestrial planetary climates. There is one vital commonality between the climates of all the planets of the solar system: Regardless of the different processes that dominate each of the climates of Earth, Mars, Venus, and Titan, they are all ultimately forced by radiation from the same star, albeit at variable distances. In Part V, Solar Influences, we discuss how the Sun's early evolution affected the climates of the terrestrial planets, and how it continues to control the temperatures and compositions of planetary atmospheres. This will be of particular interest as models of exoplanets, and the influences of much different stellar types and distances, are advanced by further observations. Comparisons of atmospheric and climate processes between the planets in our solar system has been a focus of numerous conferences over the past decade, including the Exoclimes conference series. In particular, this book project was closely tied to a conference on Comparative Climatology of Terrestrial Planets that was held in Boulder, Colorado, on June 25-28, 2012. This book benefited from the opportunity for the author teams to interact and obtain feedback from the broader community, but the chapters do not in general tie directly to presentations at the conference. The conference, which was organized by a diverse group of atmospheric and climate scientists led by Mark Bullock and Lori Glaze, sought to build connections between the various communities, focusing on synergies and complementary capabilities. Discussion panels at the end of most

  7. Characterization of extrasolar terrestrial planets from diurnal photometric variability.

    PubMed

    Ford, E B; Seager, S; Turner, E L

    2001-08-30

    The detection of massive planets orbiting nearby stars has become almost routine, but current techniques are as yet unable to detect terrestrial planets with masses comparable to the Earth's. Future space-based observatories to detect Earth-like planets are being planned. Terrestrial planets orbiting in the habitable zones of stars-where planetary surface conditions are compatible with the presence of liquid water-are of enormous interest because they might have global environments similar to Earth's and even harbour life. The light scattered by such a planet will vary in intensity and colour as the planet rotates; the resulting light curve will contain information about the planet's surface and atmospheric properties. Here we report a model that predicts features that should be discernible in the light curve obtained by low-precision photometry. For extrasolar planets similar to Earth, we expect daily flux variations of up to hundreds of per cent, depending sensitively on ice and cloud cover as well as seasonal variations. This suggests that the meteorological variability, composition of the surface (for example, ocean versus land fraction) and rotation period of an Earth-like planet could be derived from photometric observations. Even signatures of Earth-like plant life could be constrained or possibly, with further study, even uniquely determined.

  8. Modelling ocean circulation in Deep-ocean aquaplanets

    NASA Astrophysics Data System (ADS)

    McKinstry, A.

    2012-04-01

    Léger et al. (2004) and Küchner (2003) hypothesised that Ocean planets, Super-Earth planets with liquid-water oceans covering their whole surfaces may exist. Planets with liquid water surfaces could have ocean depths of 70-100 km with bottom pressures of 1-5 GPa. To date, no general circulation models have been run on such oceans, primarily because of a lack of equation of state for seawater at such depths. In this work a deep-water seawater Equation of State is implemented in the MITgcm ocean model. The EOS depends not only on the salinity and temperature but also on CO2 concentration. Several proposed ocean compositions, in particular magnesium and sodium sulphates salts ,H2O / ammonia mixes are investigated. While geothermal plumes in pure water systems will rise through an the whole ocean depths, saline-enriched plumes do not, due to differential thermal expansions for saline fluids leading to a loss of buoyancy (Melosh et al., 2004). Vance and Brown (2005) have shown that double-diffusive convection is expected to be a significant feature of such high-pressure oceans: depending on ocean composition, a double-diffusive layer will frustrate deep ocean convective processes and hence heat transfer. Convection happens separately in the warm, saline layers below and cooler, more dilute layer above. While this has been seen in isolated areas on Earth, such as the Red Sea, we explore the effects of heat and salin transfer through this layer on global circulation for deep ocean planet.

  9. The Gemini Planet Imager

    SciTech Connect

    Macintosh, B; al., e

    2006-05-02

    The next major frontier in the study of extrasolar planets is direct imaging detection of the planets themselves. With high-order adaptive optics, careful system design, and advanced coronagraphy, it is possible for an AO system on a 8-m class telescope to achieve contrast levels of 10{sup -7} to 10{sup -8}, sufficient to detect warm self-luminous Jovian planets in the solar neighborhood. Such direct detection is sensitive to planets inaccessible to current radial-velocity surveys and allows spectral characterization of the planets, shedding light on planet formation and the structure of other solar systems. We have begun the construction of such a system for the Gemini Observatory. Dubbed the Gemini Planet Imager (GPI), this instrument should be deployed in 2010 on the Gemini South telescope. It combines a 2000-actuator MEMS-based AO system, an apodized-pupil Lyot coronagraph, a precision infrared interferometer for real-time wavefront calibration at the nanometer level, and a infrared integral field spectrograph for detection and characterization of the target planets. GPI will be able to achieve Strehl ratios > 0.9 at 1.65 microns and to observe a broad sample of science targets with I band magnitudes less than 8. In addition to planet detection, GPI will also be capable of polarimetric imaging of circumstellar dust disks, studies of evolved stars, and high-Strehl imaging spectroscopy of bright targets. We present here an overview of the GPI instrument design, an error budget highlighting key technological challenges, and models of the system performance.

  10. From Disks to Planets

    NASA Astrophysics Data System (ADS)

    Youdin, Andrew N.; Kenyon, Scott J.

    This pedagogical chapter covers the theory of planet formation, with an emphasis on the physical processes relevant to current research. After summarizing empirical constraints from astronomical and geophysical data, we describe the structure and evolution of protoplanetary disks. We consider the growth of planetesimals and of larger solid protoplanets, followed by the accretion of planetary atmospheres, including the core accretion instability. We also examine the possibility that gas disks fragment directly into giant planets and/or brown dwarfs. We defer a detailed description of planet migration and dynamical evolution to other work, such as the complementary chapter in this series by Morbidelli.

  11. Challenges in planet formation

    NASA Astrophysics Data System (ADS)

    Morbidelli, Alessandro; Raymond, Sean N.

    2016-10-01

    Over the past two decades, large strides have been made in the field of planet formation. Yet fundamental questions remain. Here we review our state of understanding of five fundamental bottlenecks in planet formation. These are the following: (1) the structure and evolution of protoplanetary disks; (2) the growth of the first planetesimals; (3) orbital migration driven by interactions between protoplanets and gaseous disk; (4) the origin of the Solar System's orbital architecture; and (5) the relationship between observed super-Earths and our own terrestrial planets. Given our lack of understanding of these issues, even the most successful formation models remain on shaky ground.

  12. Minor Planet Center

    NASA Technical Reports Server (NTRS)

    Marsden, Brian G.

    1999-01-01

    This paper reports on the activities of the Minor Planet Center for the year of 1998. The main product of this center is the Minor Planet Circulars, augmented by the Minor Planet Circulars Supplement which is a new series introduced in 1997 to include the actual observations, which are now only summarized MPC. The introduction of the Daily Orbit Update (DOU) lists all the orbits computed and identification found since the previous issue. There has been a fivefold increase in the reported Near Earth Objects, which includes the addition of 55 potentially hazardous asteroids.

  13. The planets and life.

    NASA Technical Reports Server (NTRS)

    Young, R. S.

    1971-01-01

    It is pointed out that planetary exploration is not simply a program designed to detect life on another planet. A planet similar to earth, such as Mars, when studied for evidence as to why life did not arise, may turn out to be scientifically more important than a planet which has already produced a living system. Of particular interest after Mars are Venus and Jupiter. Jupiter has a primitive atmosphere which may well be synthesizing organic molecules today. Speculations have been made concerning the possibility of a bio-zone in the upper atmosphere of Venus.

  14. Planets under pressure

    NASA Astrophysics Data System (ADS)

    Jeanloz, Raymond

    2009-04-01

    Deep inside the planet Jupiter, diamonds hail down from hydrocarbon clouds as intense atmospheric pressures break methane into its atomic components. Further in - but still only 15% of the way to the planet's centre - the pressure reaches a million times that of the Earth's atmosphere. This is enough to transform hydrogen from the transparent, insulating gas we know at our planet's surface into a metallic fluid that sustains Jupiter's huge magnetic field. Even diamond is not forever: at pressures of 8-10 million atmospheres it is transformed into an opaque, metallic form of carbon, rather than the familiar transparent crystal.

  15. Our Changing Planet

    DTIC Science & Technology

    2003-01-01

    2003 2. REPORT TYPE 3. DATES COVERED 00-00-2003 to 00-00-2003 4. TITLE AND SUBTITLE Our Changing Planet 5a. CONTRACT NUMBER 5b. GRANT NUMBER...Budget Erin Wuchte Office of Management and Budget Margaret R. McCalla Office of the Federal Coordinator for Meteorology OUR CHANGING PLANET THE FISCAL...you a copy of Our Changing Planet : The FY 2003 U.S. Global Change Research Program and Climate Change Research Initiative. The report describes the

  16. Popularizing Space Education in Indian Context

    NASA Astrophysics Data System (ADS)

    Yalagi, Amrut

    Indians have many mythological stories about many constellations and stars. Hindu months are based on MOON and 27 stars on Zodiac. They are very important for many Indians in ritual, religious functions. By prompting them to identify their birth star, really makes them elevated. Similarly conveying them the importance of star gazing with respect to their day today life makes them to take interest and active participation in Space Activities. Space activities should be driven by public; their requirements; their dreams and imaginations. Their active participation definitely gives valuable inputs to space scientists. Hence, there is a need of involving common man or public mass by appropriate motivation by organising sky gazing sessions, exhibitions, workshops, etc. In this connection, even if the some organisation are able to attract a small percent of qualified engineers/scientists,, enthusiastic students, it would result in the creation of a sizable pool of talent in space sciences,which may well determine the future mankind on this planet. Some simple motivation acts have made the people to take interest in space. we have been using certain methodologies to popularize space science - 1] Conducting theory sessions on basics of star gazing and conveying importance of sky gazing with respect to day-today life. 2] Organising seminars, workshops, lectures and other academic/popular science activities with special reference to space science 3] Projects - a] Cubsat Missions b] Automatic Weather Station Facility c] Model making d] Creating and simulating space models and rover making competitions. The 50 year's of Exploration has left tremendous impact on many society's working towards space education and exploration.

  17. Possibilities for the Detection of Microbial Life on Extrasolar Planets

    NASA Astrophysics Data System (ADS)

    Knacke, Roger F.

    2003-11-01

    We consider possibilities for the remote detection of microbial life on extrasolar planets. The Darwin/Terrestrial Planet Finder (TPF) telescope concepts for observations of terrestrial planets focus on indirect searches for life through the detection of atmospheric gases related to life processes. Direct detection of extraterrestrial life may also be possible through well-designed searches for microbial life forms. Satellites in Earth orbit routinely monitor colonies of terrestrial algae in oceans and lakes by analysis of reflected ocean light in the visible region of the spectrum. These remote sensing techniques suggest strategies for extrasolar searches for signatures of chlorophylls and related photosynthetic compounds associated with life. However, identification of such life-related compounds on extrasolar planets would require observations through strong, interfering absorptions and scattering radiances from the remote atmospheres and landmasses. Techniques for removal of interfering radiances have been extensively developed for remote sensing from Earth orbit. Comparable techniques would have to be developed for extrasolar planet observations also, but doing so would be challenging for a remote planet. Darwin/TPF coronagraph concepts operating in the visible seem to be best suited for searches for extrasolar microbial life forms with instruments that can be projected for the 2010-2020 decades, although resolution and signal-to-noise ratio constraints severely limit detection possibilities on terrestrial-type planets. The generation of telescopes with large apertures and extremely high spatial resolutions that will follow Darwin/TPF could offer striking possibilities for the direct detection of extrasolar microbial life.

  18. Possibilities for the detection of microbial life on extrasolar planets.

    PubMed

    Knacke, Roger F

    2003-01-01

    We consider possibilities for the remote detection of microbial life on extrasolar planets. The Darwin/Terrestrial Planet Finder (TPF) telescope concepts for observations of terrestrial planets focus on indirect searches for life through the detection of atmospheric gases related to life processes. Direct detection of extraterrestrial life may also be possible through well-designed searches for microbial life forms. Satellites in Earth orbit routinely monitor colonies of terrestrial algae in oceans and lakes by analysis of reflected ocean light in the visible region of the spectrum. These remote sensing techniques suggest strategies for extrasolar searches for signatures of chlorophylls and related photosynthetic compounds associated with life. However, identification of such life-related compounds on extrasolar planets would require observations through strong, interfering absorptions and scattering radiances from the remote atmospheres and landmasses. Techniques for removal of interfering radiances have been extensively developed for remote sensing from Earth orbit. Comparable techniques would have to be developed for extrasolar planet observations also, but doing so would be challenging for a remote planet. Darwin/TPF coronagraph concepts operating in the visible seem to be best suited for searches for extrasolar microbial life forms with instruments that can be projected for the 2010-2020 decades, although resolution and signal-to-noise ratio constraints severely limit detection possibilities on terrestrial-type planets. The generation of telescopes with large apertures and extremely high spatial resolutions that will follow Darwin/TPF could offer striking possibilities for the direct detection of extrasolar microbial life.

  19. Magnetic Mystery Planets

    NASA Astrophysics Data System (ADS)

    Fillingim, M. O.; Brain, D. A.; Peticolas, L. M.; Yan, D.; Fricke, K. W.; Thrall, L.

    2013-12-01

    The magnetic fields of the large terrestrial planets, Venus, Earth, and Mars, are all vastly different from each other. These differences can tell us a lot about the interior structure, interior history, and even give us clues to the atmospheric history of these planets. This presentation highlights a classroom presentation and accompanying activity that focuses on the differences between the magnetic fields of Venus, Earth, and Mars, what these differences mean, and how we measure these differences. During the activity, students make magnetic field measurements and draw magnetic field lines around "mystery planets" using orbiting "spacecraft" (small compasses). Based on their observations, the students then determine whether they are orbiting Venus-like, Earth-like, or Mars-like planets. This activity is targeted to middle/high school age audiences. However, we also show a scaled-down version that has been used with elementary school age audiences.

  20. Kepler's Multiple Planet Systems

    NASA Technical Reports Server (NTRS)

    Lissauer, Jack J.

    2012-01-01

    Among the 1800 Kepler targets that have candidate planets, 20% have two or more candidate planets. While most of these objects have not yet been confirmed as true planets, several considerations strongly suggest that the vast majority of these multi-candidate systems are true planetary systems. Virtually all candidate systems are stable, as tested by numerical integrations (assuming a nominal mass-radius relationship). Statistical studies performed on these candidates reveal a great deal about the architecture of planetary systems, including the typical spacing of orbits and flatness of planetary systems. The distribution of observed period ratios shows that the vast majority of candidate pairs are neither in nor near low-order mean motion resonances. Nonetheless, there are small but statistically significant excesses of candidate pairs both in resonance and spaced slightly too far apart to be in resonance, particularly near the 2:1 resonance. The characteristics of the confirmed Kepler multi-planet systems will also be discussed.

  1. Managing Planet Earth.

    ERIC Educational Resources Information Center

    Clark, William C.

    1989-01-01

    Discusses the human use of the planet earth. Describes the global patterns and the regional aspects of change. Four requirements for the cultivation of leadership and institutional competence are suggested. Lists five references for further reading. (YP)

  2. Students Discover Unique Planet

    NASA Astrophysics Data System (ADS)

    2008-12-01

    Three undergraduate students, from Leiden University in the Netherlands, have discovered an extrasolar planet. The extraordinary find, which turned up during their research project, is about five times as massive as Jupiter. This is also the first planet discovered orbiting a fast-rotating hot star. Omega Centauri ESO PR Photo 45a/08 A planet around a hot star The students were testing a method of investigating the light fluctuations of thousands of stars in the OGLE database in an automated way. The brightness of one of the stars was found to decrease for two hours every 2.5 days by about one percent. Follow-up observations, taken with ESO's Very Large Telescope in Chile, confirmed that this phenomenon is caused by a planet passing in front of the star, blocking part of the starlight at regular intervals. According to Ignas Snellen, supervisor of the research project, the discovery was a complete surprise. "The project was actually meant to teach the students how to develop search algorithms. But they did so well that there was time to test their algorithm on a so far unexplored database. At some point they came into my office and showed me this light curve. I was completely taken aback!" The students, Meta de Hoon, Remco van der Burg, and Francis Vuijsje, are very enthusiastic. "It is exciting not just to find a planet, but to find one as unusual as this one; it turns out to be the first planet discovered around a fast rotating star, and it's also the hottest star found with a planet," says Meta. "The computer needed more than a thousand hours to do all the calculations," continues Remco. The planet is given the prosaic name OGLE2-TR-L9b. "But amongst ourselves we call it ReMeFra-1, after Remco, Meta, and myself," says Francis. The planet was discovered by looking at the brightness variations of about 15 700 stars, which had been observed by the OGLE survey once or twice per night for about four years between 1997 and 2000. Because the data had been made public

  3. Transit of Extrasolar Planets

    NASA Technical Reports Server (NTRS)

    Doyle, Laurance R.

    1998-01-01

    During the past five years we have pursued the detection of extrasolar planets by the photometric transit method, i.e. the detection of a planet by watching for a drop in the brightness of the light as it crosses in front of a star. The planetary orbit must cross the line-of-sight and so most systems will not be lined up for such a transit to ever occur. However, we have looked at eclipsing binary systems which are already edge-on. Such systems must be very small in size as this makes the differential light change due to a transit much greater for a given planet size (the brightness difference will be proportional to the area of the transiting planet to the disc area of the star). Also, the planet forming region should be closer to the star as small stars are generally less luminous (that is, if the same thermal regime for planet formation applies as in the solar system). This led to studies of the habitable zone around other stars, as well. Finally, we discovered that our data could be used to detect giant planets without transits as we had been carefully timing the eclipses of the stars (using a GPS antenna for time) and this will drift by being offset by any giant planets orbiting around the system, as well. The best summary of our work may be to just summarize the 21 refereed papers produced during the time of this grant. This will be done is chronological order and in each section separately.

  4. Planets' magnetic environments

    SciTech Connect

    Lanzerotti, L.J.; Uberoi, C.

    1989-02-01

    The magnetospheres of Mercury, Venus, Mars, Jupiter, Saturn, Uranus, and comets and the heliomagnetosphere are examined. The orientations of the planetary spin and magnetic axes, the size of the magnetospheres, and the magnetic properties and the radio emissions of the planets are compared. Results from spacecraft studies of the planets are included. Plans for the Voyager 2 mission and its expected study of the Neptune magnetosphere are considered.

  5. Outer planet satellites

    SciTech Connect

    Schenk, P.M. )

    1991-01-01

    Recent findings on the outer-planet satellites are presented, with special consideration given to data on the rheologic properties of ice on icy satellites, the satellite surfaces and exogenic processes, cratering on dead cratered satellites, volcanism, and the interiors of outer-planet satellites. Particular attention is given to the state of Titan's surface and the properties of Triton, Pluto, and Charon. 210 refs.

  6. The planet Saturn (1970)

    NASA Technical Reports Server (NTRS)

    1972-01-01

    The present-day knowledge on Saturn and its environment are described for designers of spacecraft which are to encounter and investigate the planet. The discussion includes physical properties of the planet, gravitational field, magnetic and electric fields, electromagnetic radiation, satellites and meteoroids, the ring system, charged particles, atmospheric composition and structure, and clouds and atmospheric motions. The environmental factors which have pertinence to spacecraft design criteria are also discussed.

  7. The planet Mercury (1971)

    NASA Technical Reports Server (NTRS)

    1972-01-01

    The physical properties of the planet Mercury, its surface, and atmosphere are presented for space vehicle design criteria. The mass, dimensions, mean density, and orbital and rotational motions are described. The gravity field, magnetic field, electromagnetic radiation, and charged particles in the planet's orbit are discussed. Atmospheric pressure, temperature, and composition data are given along with the surface composition, soil mechanical properties, and topography, and the surface electromagnetic and temperature properties.

  8. Building a virtual planet

    NASA Technical Reports Server (NTRS)

    Meadows, V. S.

    2002-01-01

    The virtual Planetary Laboratory (VPL) is a recently funded 5-yr project, which seeks toimprove our understanding of the range of plausible environments and the likely signatures for life on extrasolar terrestrial planets. To achieve these goals we are developing a suite of innovative modeling tools to simulate the environments and spectra of extrasolar planets. The core of the VPL IS a coupled radiative transfer/climate/chemistry model, which is augmented by interchangeable modules which characterize geological, exogenic, atmospheric escape, and life processes. The VPL is validated using data derived from terrestrial planets within our own solar system. The VPL will be used to explore the plausible range of atmospheric composittions and globally averaged spectra for extrasolar planets and for early Earth, and will improve our understanding of the effect of life on a planet's atmospheric spectrum and composition. The models will also be used to create a comprehensive spectral catalog to provide recommendations on the optimum wavelength range, spectral resolution, and instrument sensitivity required to characterize extrasolar terrestrial planets. Although developed by our team, the VPL is envisioned to be a comprehensive and flexible tool, which can be collaboratively used by the broader planetary science and astrobiology communities. This presentation will describe the project concept, the tasks involved, and will outline current progress to date. This work is funded by the NASA Astrobiology Institute.

  9. The Atmospheres of Extrasolar Planets

    NASA Technical Reports Server (NTRS)

    Richardson, L. J.; Seager, S.

    2007-01-01

    In this chapter we examine what can be learned about extrasolar planet atmospheres by concentrating on a class of planets that transit their parent stars. As discussed in the previous chapter, one way of detecting an extrasolar planet is by observing the drop in stellar intensity as the planet passes in front of the star. A transit represents a special case in which the geometry of the planetary system is such that the planet s orbit is nearly edge-on as seen from Earth. As we will explore, the transiting planets provide opportunities for detailed follow-up observations that allow physical characterization of extrasolar planets, probing their bulk compositions and atmospheres.

  10. All for the Planet, the Planet for everyone!

    NASA Astrophysics Data System (ADS)

    Drndarski, Marina

    2014-05-01

    The Eco-Musketeers are unique voluntary group of students. They have been established in Belgrade, in Primary school 'Drinka Pavlović'. Since the founding in year 2000, Eco-Musketeers have been involved in peer and citizens education guided by motto: All for the planet, the planet for all! Main goals of this group are spreading and popularization of environmental approach as well as gaining knowledge through collaborative projects and research. A great number of students from other schools in Serbia have joined Eco-Musketeers in observations aiming to better understand the problem of global climate change. In the past several years Eco-Musketeers have also participated in many national and international projects related to the active citizenship and rising the awareness of the importance of biodiversity and environment for sustainable development of society. In this presentation we will show some of the main activities, eco-performances and actions of our organization related to the environment, biodiversity, conservation and recycling, such as: spring cleaning the streets of Belgrade, cleaning the Sava and the Danube river banks, removing insect moth pupae in the area of Lipovica forest near Belgrade. Also, Eco-Musketeers worked on education of employees of Coca-Cola HBC Serbia about energy efficiency. All the time, we have working on raising public awareness of the harmful effects of plastic bags on the environment, too. In order to draw attention on rare and endangered species in Serbia and around the globe, there were several performing street-plays about biodiversity and also the plays about the water ecological footprint. Eco-Musketeers also participated in international projects Greenwave-signs of spring (Fibonacci project), European Schools For A Living Planet (WWF Austria and Erste stiftung) and Eco Schools. The eco dream of Eco-Musketeers is to influence the Government of the Republic of Serbia to determine and declare a 'green habits week'. This should

  11. Extrasolar binary planets. I. Formation by tidal capture during planet-planet scattering

    SciTech Connect

    Ochiai, H.; Nagasawa, M.; Ida, S.

    2014-08-01

    We have investigated (1) the formation of gravitationally bounded pairs of gas-giant planets (which we call 'binary planets') from capturing each other through planet-planet dynamical tide during their close encounters and (2) the subsequent long-term orbital evolution due to planet-planet and planet-star quasi-static tides. For the initial evolution in phase 1, we carried out N-body simulations of the systems consisting of three Jupiter-mass planets taking into account the dynamical tide. The formation rate of the binary planets is as much as 10% of the systems that undergo orbital crossing, and this fraction is almost independent of the initial stellarcentric semimajor axes of the planets, while ejection and merging rates sensitively depend on the semimajor axes. As a result of circularization by the planet-planet dynamical tide, typical binary separations are a few times the sum of the physical radii of the planets. After the orbital circularization, the evolution of the binary system is governed by long-term quasi-static tide. We analytically calculated the quasi-static tidal evolution in phase 2. The binary planets first enter the spin-orbit synchronous state by the planet-planet tide. The planet-star tide removes angular momentum of the binary motion, eventually resulting in a collision between the planets. However, we found that the binary planets survive the tidal decay for the main-sequence lifetime of solar-type stars (∼10 Gyr), if the binary planets are beyond ∼0.3 AU from the central stars. These results suggest that the binary planets can be detected by transit observations at ≳ 0.3 AU.

  12. Reinflating Giant Planets

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2017-01-01

    Two new, large gas-giant exoplanets have been discovered orbiting close to their host stars. A recent study examining these planets and others like them may help us to better understand what happens to close-in hot Jupiters as their host stars reach the end of their main-sequence lives.OversizedGiantsUnbinned transit light curves for HAT-P-65b. [Adapted from Hartman et al. 2016]The discovery of HAT-P-65b and HAT-P-66b, two new transiting hot Jupiters, is intriguing. These planets have periods of just under 3 days and masses of roughly 0.5 and 0.8 times that of Jupiter, but their sizes are whats really interesting: they have inflated radii of 1.89 and 1.59 times that of Jupiter.These two planets, discovered using the Hungarian-made Automated Telescope Network (HATNet) in Arizona and Hawaii, mark the latest in an ever-growing sample of gas-giant exoplanets with radii larger than expected based on theoretical planetary structure models.What causes this discrepancy? Did the planets just fail to contract to the expected size when they were initially formed, or were they reinflated later in their lifetimes? If the latter, how? These are questions that scientists are only now starting to be able to address using statistics of the sample of close-in, transiting planets.Unbinned transit light curves for HAT-P-66b. [Hartman et al. 2016]Exploring Other PlanetsLed by Joel Hartman (Princeton University), the team that discovered HAT-P-65b and HAT-P-66b has examined these planets observed parameters and those of dozens of other known close-in, transiting exoplanets discovered with a variety of transiting exoplanet missions: HAT, WASP, Kepler, TrES, and KELT. Hartman and collaborators used this sample to draw conclusions about what causes some of these planets to have such large radii.The team found that there is a statistically significant correlation between the radii of close-in giant planets and the fractional ages of their host stars (i.e., the stars age divided by its full

  13. Water loss from terrestrial planets orbiting ultracool dwarfs: implications for the planets of TRAPPIST-1

    NASA Astrophysics Data System (ADS)

    Bolmont, E.; Selsis, F.; Owen, J. E.; Ribas, I.; Raymond, S. N.; Leconte, J.; Gillon, M.

    2017-01-01

    Ultracool dwarfs (UCD; Teff < ˜3000 K) cool to settle on the main sequence after ˜1 Gyr. For brown dwarfs, this cooling never stops. Their habitable zones (HZ) thus sweeps inward at least during the first Gyr of their lives. Assuming they possess water, planets found in the HZ of UCDs have experienced a runaway greenhouse phase too hot for liquid water prior to enter the HZ. It has been proposed that such planets are desiccated by this hot early phase and enter the HZ as dry worlds. Here, we model the water loss during this pre-HZ hot phase taking into account recent upper limits on the XUV emission of UCDs and using 1D radiation-hydrodynamic simulations. We address the whole range of UCDs but also focus on the planets recently found around the 0.08 M⊙ dwarf TRAPPIST-1. Despite assumptions maximizing the FUV photolysis of water and the XUV-driven escape of hydrogen, we find that planets can retain significant amount of water in the HZ of UCDs, with a sweet spot in the 0.04-0.06 M⊙ range. We also studied the TRAPPIST-1 system using observed constraints on the XUV flux. We find that TRAPPIST-1b and c may have lost as much as 15 Earth oceans and planet d - which might be inside the HZ - may have lost less than 1 Earth ocean. Depending on their initial water contents, they could have enough water to remain habitable. TRAPPIST-1 planets are key targets for atmospheric characterization and could provide strong constraints on the water erosion around UCDs.

  14. Water loss from terrestrial planets orbiting ultracool dwarfs: Implications for the planets of TRAPPIST-1

    NASA Astrophysics Data System (ADS)

    Bolmont, Emeline; Selsis, Franck; Owen, James E.; Ribas, Ignasi; Raymond, Sean N.; Leconte, Jérémy; Gillon, Michael

    2016-10-01

    Ultracool dwarfs (UCDs) encompass the population of extremely low mass stars (later than M6-type) and brown dwarfs.Because UCDs cool monotonically, their habitable zone (HZ) sweeps inward in time.Assuming they possess water, planets found in the HZ of UCDs have experienced a runaway greenhouse phase too hot for liquid water prior to entering the HZ.It has been proposed that such planets are desiccated by this hot early phase and enter the HZ as dry, inhospitable worlds.Here we model the water loss during this pre-HZ hot phase taking into account recent upper limits on the XUV emission of UCDs and using 1D radiation-hydrodynamic simulations.We address the whole range of UCDs but also focus on the planets b, c and d recently found around the 0.08 M⊙ dwarf TRAPPIST-1.Despite assumptions maximizing the FUV-photolysis of water and the XUV-driven escape of hydrogen, we find that planets can retain significant amounts of water in the HZ of UCDs, with a sweet spot in the 0.04-0.06 M⊙ range.We also studied the TRAPPIST-1 system using observed constraints on the XUV-flux.We found that TRAPPIST-1b and c can lose as much as 15 Earth Ocean and planet d -- which may be inside the HZ depending on its actual period -- may have lost less than 1 Earth Ocean.Depending on its initial content, they could have enough water to remain habitable.TRAPPIST-1 planets are key targets for atmospheric characterization and could provide strong constraints on the water erosion around UCDs.

  15. In Defense of Popular Music.

    ERIC Educational Resources Information Center

    Luebke, Steven R.

    In his book "The Closing of the American Mind," Allan Bloom criticizes popular music for the "emptiness of its values." It has only one appeal, says Bloom, "a barbaric appeal, to sexual desire--not love, not eros, but sexual desire, undeveloped and untutored." However, to say "rock music is this or that" is…

  16. Arab Stereotypes in Popular Fiction.

    ERIC Educational Resources Information Center

    Terry, Janice J.

    1983-01-01

    Most popular fictional plots involving the Middle East--adventure stories, espionage, and themes of Western dependency on Arab oil--portray the Israelies as the good guys and the Arabs as the villians. People must be made aware that fictional literature is prejudiced and racially biased against Arabs. (RM)

  17. Readers' Knowledge of Popular Genre

    ERIC Educational Resources Information Center

    Dixon, Peter; Bortolussi, Marisa

    2009-01-01

    This research examined readers' knowledge of popular genres. Participants wrote short essays on fantasy, science fiction, or romance. The similarities among the essays were measured using latent semantic analysis (LSA) and were then analyzed using multidimensional scaling and cluster analysis. The clusters and scales were interpreted by searching…

  18. Popular Education in Solidarity Economy

    ERIC Educational Resources Information Center

    de Melo Neto, José Francisco; da Costa, Francisco Xavier Pereira

    2015-01-01

    This article seeks to show the relation between popular education and solidarity economy in experiences of solidarity economy enterprises in Brazil. It is based on diverse experiences which have occurred in various sectors of this economy, highlighting those experiences which took place in João Pessoa with the creation of a Cooperative of Workers…

  19. Protostars and Planets VI

    NASA Astrophysics Data System (ADS)

    Beuther, Henrik; Klessen, Ralf S.; Dullemond, Cornelis P.; Henning, Thomas

    The Protostars and Planets book and conference series has been a long-standing tradition that commenced with the first meeting led by Tom Gehrels and held in Tucson, Arizona, in 1978. The goal then, as it still is today, was to bridge the gap between the fields of star and planet formation as well as the investigation of planetary systems and planets. As Tom Gehrels stated in the preface to the first Protostars and Planets book, "Cross-fertilization of information and understanding is bound to occur when investigators who are familiar with the stellar and interstellar phases meet with those who study the early phases of solar system formation." The central goal remained the same for the subsequent editions of the books and conferences Protostars and Planets II in 1984, Protostars and Planets III in 1990, Protostars and Planets IV in 1998, and Protostars and Planets V in 2005, but has now been greatly expanded by the flood of new discoveries in the field of exoplanet science. The original concept of the Protostars and Planets series also formed the basis for the sixth conference in the series, which took place on July 15-20, 2013. It was held for the first time outside of the United States in the bustling university town of Heidelberg, Germany. The meeting attracted 852 participants from 32 countries, and was centered around 38 review talks and more than 600 posters. The review talks were expanded to form the 38 chapters of this book, written by a total of 250 contributing authors. This Protostars and Planets volume reflects the current state-of-the-art in star and planet formation, and tightly connects the fields with each other. It is structured into four sections covering key aspects of molecular cloud and star formation, disk formation and evolution, planetary systems, and astrophysical conditions for life. All poster presentations from the conference can be found at www.ppvi.org. In the eight years that have passed since the fifth conference and book in the

  20. Climate model studies of synchronously rotating planets.

    PubMed

    Joshi, Manoj

    2003-01-01

    M stars constitute 75% of main sequence stars though, until recently, their star systems have not been considered suitable places for habitable planets to exist. In this study the climate of a synchronously rotating planet around an M dwarf star is evaluated using a three-dimensional global atmospheric circulation model. The presence of clouds and evaporative cooling at the surface of the planet result in a cooler surface temperature at the subsolar point. Water ice forms at the polar regions and on the dark side, where the minimum temperature lies between -30 degrees C and 0 degrees C. As expected, rainfall is extremely high on the starlit side and extremely low on the dark side. The presence of a dry continent causes higher temperatures on the dayside, and allows accumulation of snow on the nightside. The absence of any oceans leads to higher day-night temperature differences, consistent with previous work. The present study reinforces recent conclusions that synchronously rotating planets within the circumstellar habitable zones of M dwarf stars should be habitable, and therefore M dwarf systems should not be excluded in future searches for exoplanets.

  1. Appearance of high-pressure H2O ice on ice-covered terrestrial planets

    NASA Astrophysics Data System (ADS)

    Ueta, S.; Sasaki, T.

    2014-03-01

    A lot of terrestrial exoplanets and free-floating planets have been discovered. Whether terrestrial planets with liquid water exist is an important question to consider, especially in terms of their habitability. Even in a globally ice-covered state, liquid water could exist beneath the surface ice shell because sufficient geothermal heat flow from the planetary interior is likely to melt the interior ice, so that an internal ocean under the surface ice shell could appear (e.g., Hoffman & Schrag 2002). In this study, we argue the conditions that must be satisfied for ice-covered terrestrial planets to have an internal ocean on the timescale of planetary evolution (Ueta & Sasaki 2013). Geothermal heat flow calculated by a parameterized convection model (e.g., McGovern & Schubert 1989) is considered as the heat source at the origin of the internal ocean. By applying and improving the model of Tajika (2008), we also examine how the amount of radiogenic heat and H2O mass affect these conditions. Moreover, we investigate the structures of surface H2O layers of ice-covered planets by considering the effects of ice under high pressure (high-pressure ice). At 1 AU from the central star, as shown in Fig. 1, a 1M.+ planet with 0.6-25 times H2O mass of the Earth could have an internal ocean. When the planet has an H2O mass over 25 times that of the Earth, high-pressure ice layers may appear between the internal ocean and the rock-part of the planet. The results indicate that planetary size and surface H2O mass strongly ristrict the conditions under which an extrasolar terrestrial planet could have an internal ocean without high-pressure ice existing under the internal ocean. The habitability of a planet might be influenced by the existence of such high-pressure ice layers.

  2. Astrobiological and Geological Implications of Convective Transport in Icy Outer Planet Satellites

    NASA Technical Reports Server (NTRS)

    Pappalardo, Robert T.; Zhong, Shi-Jie; Barr, Amy

    2005-01-01

    The oceans of large icy outer planet satellites are prime targets in the search for extraterrestrial life in our solar system. The goal of our project has been to develop models of ice convection in order to understand convection as an astrobiologically relevant transport mechanism within icy satellites, especially Europa. These models provide valuable constraints on modes of surface deformation and thus the implications of satellite surface geology for astrobiology, and for planetary protection. Over the term of this project, significant progress has been made in three areas: (1) the initiation of convection in large icy satellites, which we find probably requires tidal heating; (2) the relationship of surface features on Europa to internal ice convection, including the likely role of low-melting-temperature impurities; and (3) the effectiveness of convection as an agent of icy satellite surface-ocean material exchange, which seems most plausible if tidal heating, compositional buoyancy, and solid-state convection work in combination. Descriptions of associated publications include: 3 published papers (including contributions to 1 review chapter), 1 manuscript in revision, 1 manuscript in preparation (currently being completed under separate funding), and 1 published popular article. A myriad of conference abstracts have also been published, and only those from the past year are listed.

  3. Recipes for planet formation

    NASA Astrophysics Data System (ADS)

    Meyer, Michael R.

    2009-11-01

    Anyone who has ever used baking soda instead of baking powder when trying to make a cake knows a simple truth: ingredients matter. The same is true for planet formation. Planets are made from the materials that coalesce in a rotating disk around young stars - essentially the "leftovers" from when the stars themselves formed through the gravitational collapse of rotating clouds of gas and dust. The planet-making disk should therefore initially have the same gas-to-dust ratio as the interstellar medium: about 100 to 1, by mass. Similarly, it seems logical that the elemental composition of the disk should match that of the star, reflecting the initial conditions at that particular spot in the galaxy.

  4. Magnetic Mystery Planets

    NASA Astrophysics Data System (ADS)

    Fillingim, M.; Brain, D.; Peticolas, L.; Yan, D.; Fricke, K.; Thrall, L.

    2014-07-01

    The magnetic fields of the large terrestrial planets, Venus, Earth, and Mars, are all vastly different from each other. These differences can tell us a lot about the interior structure, interior history, and they can even give us clues to the atmospheric history of these planets. This paper highlights a classroom presentation and accompanying activity that focuses on the differences between the magnetic fields of Venus, Earth, and Mars, what these differences mean, and how we measure these differences. During the activity, students make magnetic field measurements and draw magnetic field lines of “mystery planets” using orbiting “spacecraft” (small compasses). Based on their observations, the students then determine whether they are orbiting Venus-like, Earth-like, or Mars-like planets. This activity is targeted to middle and high school audiences. However, we have also used a scaled-down version with elementary school audiences.

  5. Primordial Planets Explain Interstellar Dust, the Formation of Life; and Falsify Dark Energy

    NASA Astrophysics Data System (ADS)

    Gibson, Carl H.; Wickramasinghe, N. Chandra; Schild, Rudolph E.

    2011-12-01

    Hydrogravitional-dynamics (HGD) cosmology of Gibson/Schild 1996 predicts proto-globular-star- cluster clumps of Earth-mass planets fragmented from plasma at 300 Kyr. Stars promptly formed from mergers of these gas planets, and chemicals C, N, O, Fe etc. were created by the stars and their supernovae. Seeded gas planets reduced the oxides to hot water oceans. Water oceans at critical temperature 647 K then hosted the first organic chemistry and the first life, distributed to the 1080 planets of the cosmological big bang by comets produced by the new (HGD) planet-merger star formation mechanism. This biological big bang began at 2 Myr when liquid oceans condensed. Life distributed by Hoyle/Wickramasinghe cometary panspermia evolved in a cosmological primordial soup of the merging planets throughout the universe. A primordial astrophysical basis is provided for astrobiology by HGD cosmology. Concordance ΛCDMHC cosmology is rendered obsolete by the observation of complex life on Earth, falsifying the dark energy and cold dark matter concepts. The dark matter of galaxies is mostly primordial planets in protoglobularstarcluster clumps, 30,000,000 planets per star (not 8!). Complex organic chemicals of the interstellar dust is formed by life on these planets, and distributed by their comets.

  6. Imaging Extrasolar Giant Planets

    NASA Astrophysics Data System (ADS)

    Bowler, Brendan P.

    2016-10-01

    High-contrast adaptive optics (AO) imaging is a powerful technique to probe the architectures of planetary systems from the outside-in and survey the atmospheres of self-luminous giant planets. Direct imaging has rapidly matured over the past decade and especially the last few years with the advent of high-order AO systems, dedicated planet-finding instruments with specialized coronagraphs, and innovative observing and post-processing strategies to suppress speckle noise. This review summarizes recent progress in high-contrast imaging with particular emphasis on observational results, discoveries near and below the deuterium-burning limit, and a practical overview of large-scale surveys and dedicated instruments. I conclude with a statistical meta-analysis of deep imaging surveys in the literature. Based on observations of 384 unique and single young (≈5-300 Myr) stars spanning stellar masses between 0.1 and 3.0 M ⊙, the overall occurrence rate of 5-13 M Jup companions at orbital distances of 30-300 au is {0.6}-0.5+0.7 % assuming hot-start evolutionary models. The most massive giant planets regularly accessible to direct imaging are about as rare as hot Jupiters are around Sun-like stars. Dividing this sample into individual stellar mass bins does not reveal any statistically significant trend in planet frequency with host mass: giant planets are found around {2.8}-2.3+3.7 % of BA stars, <4.1% of FGK stars, and <3.9% of M dwarfs. Looking forward, extreme AO systems and the next generation of ground- and space-based telescopes with smaller inner working angles and deeper detection limits will increase the pace of discovery to ultimately map the demographics, composition, evolution, and origin of planets spanning a broad range of masses and ages.

  7. Mission to Planet Earth

    NASA Technical Reports Server (NTRS)

    Tilford, Shelby G.; Asrar, Ghassem; Backlund, Peter W.

    1994-01-01

    Mission to Planet Earth (MTPE) is NASA's concept for an international science program to produce the understanding needed to predict changes in the Earth's environment. NASA and its interagency and international partners will place satellites carrying advanced sensors in strategic Earth orbits to gather multidisciplinary data. A sophisticated data system will process and archive an unprecedented amount of information about the Earth and how it works as a system. Increased understanding of the Earth system is a basic human responsibility, a prerequisite to informed management of the planet's resources and to the preservation of the global environment.

  8. Location of Planet X

    SciTech Connect

    Harrington, R.S.

    1988-10-01

    Observed positions of Uranus and Neptune along with residuals in right ascension and declination are used to constrain the location of a postulated tenth planet. The residuals are converted into residuals in ecliptic longitude and latitude. The results are then combined into seasonal normal points, producing average geocentric residuals spaced slightly more than a year apart that are assumed to represent the equivalent heliocentric average residuals for the observed oppositions. Such a planet is found to most likely reside in the region of Scorpius, with considerably less likelihood that it is in Taurus. 8 references.

  9. Heat Pipe Planets

    NASA Technical Reports Server (NTRS)

    Moore, William B.; Simon, Justin I.; Webb, A. Alexander G.

    2014-01-01

    When volcanism dominates heat transport, a terrestrial body enters a heat-pipe mode, in which hot magma moves through the lithosphere in narrow channels. Even at high heat flow, a heat-pipe planet develops a thick, cold, downwards-advecting lithosphere dominated by (ultra-)mafic flows and contractional deformation at the surface. Heat-pipes are an important feature of terrestrial planets at high heat flow, as illustrated by Io. Evidence for their operation early in Earth's history suggests that all terrestrial bodies should experience an episode of heat-pipe cooling early in their histories.

  10. Mission to Planet Earth

    NASA Technical Reports Server (NTRS)

    Wilson, Gregory S.; Backlund, Peter W.

    1992-01-01

    Mission to Planet Earth (MTPE) is NASA's concept for an international science program to produce the understanding needed to predict changes in the earth's environment. NASA and its interagency and international partners will place satellites carrying advanced sensors in strategic earth orbits to gather multidisciplinary data. A sophisticated data system will process and archive an unprecedented amount of information about the earth and how it works as a system. Increased understanding of the earth system is a basic human responsibility, a prerequisite to informed management of the planet's resources and to the preservation of the global environment.

  11. Popular Culture and the Teaching of English.

    ERIC Educational Resources Information Center

    Donelson, Ken, Ed.

    1975-01-01

    This issue of the "Arizona English Bulletin" contains 38 articles related to popular culture and the teaching of English. The articles discuss such topics as language in the popular arts, establishing a popular culture library, defining sexism in popular culture, detective literature and its uses in the traditional classroom, popular…

  12. The deep ocean under climate change.

    PubMed

    Levin, Lisa A; Le Bris, Nadine

    2015-11-13

    The deep ocean absorbs vast amounts of heat and carbon dioxide, providing a critical buffer to climate change but exposing vulnerable ecosystems to combined stresses of warming, ocean acidification, deoxygenation, and altered food inputs. Resulting changes may threaten biodiversity and compromise key ocean services that maintain a healthy planet and human livelihoods. There exist large gaps in understanding of the physical and ecological feedbacks that will occur. Explicit recognition of deep-ocean climate mitigation and inclusion in adaptation planning by the United Nations Framework Convention on Climate Change (UNFCCC) could help to expand deep-ocean research and observation and to protect the integrity and functions of deep-ocean ecosystems.

  13. The deep ocean under climate change

    NASA Astrophysics Data System (ADS)

    Levin, Lisa A.; Le Bris, Nadine

    2015-11-01

    The deep ocean absorbs vast amounts of heat and carbon dioxide, providing a critical buffer to climate change but exposing vulnerable ecosystems to combined stresses of warming, ocean acidification, deoxygenation, and altered food inputs. Resulting changes may threaten biodiversity and compromise key ocean services that maintain a healthy planet and human livelihoods. There exist large gaps in understanding of the physical and ecological feedbacks that will occur. Explicit recognition of deep-ocean climate mitigation and inclusion in adaptation planning by the United Nations Framework Convention on Climate Change (UNFCCC) could help to expand deep-ocean research and observation and to protect the integrity and functions of deep-ocean ecosystems.

  14. Popular democracy and waste management

    SciTech Connect

    Wallis, L.R.

    1986-01-01

    The US has moved from representative democracy to popular democracy and public scrutiny is unrelenting. Any hope of success on their part in resolving the nuclear waste question hinges on their ability to condition themselves to operate in a popular democracy environment. Those opposed to the siting of high- and low-level waste repositories have already developed a set of recurring themes: (1) the siting criteria are fatally flawed; (2) the criteria are not adequate; (3) the process is driven by politics not science; (4) unrealistic deadlines lead to dangerous shortcuts; (5) transportation experience is lacking; (6) the scientific community does not really know how to dispose of the wastes. They must continue to tell the public that if science has brought us problems, then the answer can be only more knowledge - not less. Failure by their profession to recognize that popular democracy is a fact and that nuclear issues need to be addressed in humanistic terms raises the question of whether America is philosophically suited for the expanded use of nuclear power in the future - or for that matter for leadership in the world of tomorrow.

  15. Atmospheric models for post- giant impact planets

    NASA Astrophysics Data System (ADS)

    Lupu, R.; Zahnle, K. J.; Marley, M. S.; Schaefer, L. K.; Fegley, B.; Morley, C.; Cahoy, K.; Freedman, R. S.; Fortney, J. J.

    2013-12-01

    The final assembly of terrestrial planets is now universally thought to have occurred through a series of giant impacts, such as Earth's own Moon-forming impact. These collisions take place over a time interval of about 100 million years, during which time it takes at least 10 collisions between planets to make a Venus or an Earth. In the aftermath of one of these collisions the surviving planet is hot, and can remain hot for millions of years. During this phase of accretion, the proto-terrestrial planet may have a dense steam atmosphere, that will affect both the cooling of the planet and our ability to detect it. Here we explore the atmospheric chemistry, photochemistry, and spectral signatures of post-giant-impact terrestrial planets enveloped by thick atmospheres consisting of vaporized rock material. The atmospheric chemistry is computed self-consistently for atmospheres in equilibrium with hot surfaces, with compositions reflecting either the bulk silicate Earth (BSE, which includes the crust, mantle, atmosphere and oceans) or Earth's continental crust (CC). These two cases allow us to examine differences in atmospheres formed by outgassing of silica-rich (felsic) rocks - like the Earth's continental crust - and MgO- and FeO-rich (mafic) rocks - like the BSE. Studies of detrital zircons from Jack Hills, Australia, show that the continental crust existed 164 million years after the formation of the solar system, in which case the material vaporized in a giant impact should likely reflect the CC composition. However, if at the time of impact the surface of the planet does not yet exhibit the formation of continents, then the BSE case becomes relevant. We compute atmospheric profiles for surface temperatures ranging from 1000 to 2200 K, surface pressures of 10 and 100 bar, and surface gravities of 10 and 30 m/s^2. We account for all major molecular and atomic opacity sources, including collision-induced absorption, to derive the atmospheric structure and compute

  16. Planet Formation and the Characteristics of Extrasolar Planets

    NASA Technical Reports Server (NTRS)

    Lissauer, Jack J.; DeVincenzi, Donald L. (Technical Monitor)

    2000-01-01

    An overview of current theories of planetary growth, emphasizing the formation of extrasolar planets, is presented. Models of planet formation are based upon observations of the Solar System, extrasolar planets, and young stars and their environments. Terrestrial planets are believed to grow via pairwise accretion until the spacing of planetary orbits becomes large enough that the configuration is stable for the age of the system. Giant planets begin their growth like terrestrial planets, but if they become massive enough before the protoplanetary disk dissipates, then they are able to accumulate substantial amounts of gas. These models predict that rocky planets should form in orbit about most single stars. It is uncertain whether or not gas giant planet formation is common, because most protoplanetary disks may dissipate before solid planetary cores can grow large enough to gravitationally trap substantial quantities of gas. A potential hazard to planetary systems is radial decay of planetary orbits resulting from interactions with material within the disk. Planets more massive than Earth have the potential to decay the fastest, and may be able to sweep up smaller planets in their path. The implications of the giant planets found in recent radial velocity searches for the abundances of habitable planets are discussed.

  17. Twist planet drive

    NASA Technical Reports Server (NTRS)

    Vranish, John M. (Inventor)

    1996-01-01

    A planetary gear system includes a sun gear coupled to an annular ring gear through a plurality of twist-planet gears, a speeder gear, and a ground structure having an internal ring gear. Each planet gear includes a solid gear having a first half portion in the form of a spur gear which includes vertical gear teeth and a second half portion in the form of a spur gear which includes helical gear teeth that are offset from the vertical gear teeth and which contact helical gear teeth on the speeder gear and helical gear teeth on the outer ring gear. One half of the twist planet gears are preloaded downward, while the other half are preloaded upwards, each one alternating with the other so that each one twists in a motion opposite to its neighbor when rotated until each planet gear seats against the sun gear, the outer ring gear, the speeder gear, and the inner ring gear. The resulting configuration is an improved stiff anti-backlash gear system.

  18. Planets and Pucks.

    ERIC Educational Resources Information Center

    Brueningsen, Christopher; Krawiec, Wesley

    1993-01-01

    Presents a simple activity designed to allow students to experimentally verify Kepler's second law, sometimes called the law of equal areas. It states that areas swept out by a planet as it orbits the Sun are equal for equal time intervals. (PR)

  19. Accumulation of the planets

    NASA Technical Reports Server (NTRS)

    Wetherill, G. W.

    1987-01-01

    In modeling the accumulation of planetesimals into planets, it is appropriate to distinguish between two stages: an early stage, during which approximately 10 km diameter planetesimals accumulate locally to form bodies approximate 10 to the 25th g in mass; and a later stage in which the approximately 10 to the 25th g planetesimals accumulate into the final planets. In the terrestrial planet region, an initial planetesimal swarm corresponding to the critical mass of dust layer gravitational instabilities is considered. In order to better understand the accumulation history of Mercury-sized bodies, 19 Monte-Carlo simulations of terrestrial planet growth were calculated. A Monte Carlo technique was used to investigate the orbital evolution of asteroidal collision debris produced interior to 2.6 AU. It was found that there are two regions primarily responsible for production of Earth-crossing meteoritic material and Apollo objects. The same techniques were extended to include the origin of Earth-approaching asteroidal bodies. It is found that these same two resonant mechanisms predict a steady-state number of Apollo-Amor about 1/2 that estimated based on astronomical observations.

  20. Mercury: the forgotten planet.

    NASA Astrophysics Data System (ADS)

    Nelson, R. M.

    1997-11-01

    Mercury is the neglected child of the planetary system. Only one spacecraft has every ventured near it, whereas scores have probed the moon, Venus and Mars. The scant facts available show this strange, blazingly hot planet is full of surprises: its anomalous density and magnetic field suggest that Mercury may be where to seek clues to the origin of the solar system.

  1. Making and Differentiating Planets

    NASA Astrophysics Data System (ADS)

    Taylor, G. J.

    2015-07-01

    The rocky planets formed by progressive aggregation of dust to make planetesimals which joined to make large objects called planetary embryos that finally accumulated into planets, one of which we live on. This chaotic process is complicated further by chemical changes with distance from the Sun, including differences in oxidation conditions and water concentration. Once the inner planets began to form, metallic iron sank to form cores, reacting with the rocky portions in the process. David C. Rubie (University of Bayreuth, Germany) and colleagues in Germany, France, and the United States put all this planetary action into an impressively thorough computer model of planet formation and differentiation. They show that the observed compositions of the Earth can be matched by simulations that include the Grand Tack (Jupiter and Saturn migrate inwards towards the Sun and then back out), and chemical gradients in the Solar System, with more reducing conditions near the Sun, more oxidizing farther from the Sun, and oxidizing and hydrated conditions even farther from the Sun. The study identifies other important variables, such as the extent to which metallic iron chemically equilibrated with the silicate making up the Earth's mantle, the pressure at which it happened, and the likelihood that Earth accreted heterogeneously.

  2. Accumulation of the Planets

    NASA Technical Reports Server (NTRS)

    Wetherill, George W.

    2002-01-01

    The purpose of this project is to increase understanding of planet forming processes that are likely to have occurred in the Solar System during its early evolution. This was accomplished by development of computer models that are compatible with the present state of the Solar System as well as with observational and theoretical data attained from astrophysical observations and theory.

  3. A Planet for Goldilocks

    NASA Astrophysics Data System (ADS)

    Batalha, N.

    2014-07-01

    The search for life beyond Earth has inspired Solar System exploration and SETI surveys. Today, the search for life also leads to exoplanet discovery and characterization. Launched in March 2009, NASA's Kepler Mission has discovered thousands of exoplanets with diverse properties. Though each new world is interesting in its own right, Kepler aims to understand the population as a whole. Its primary objective is to determine the frequency of exoplanets of different sizes and orbital periods. Of special interest are the Earth-size planets in the “Goldilocks” (or habitable) Zone where the flux of incoming starlight is conducive to the existence of surface liquid water. Once Kepler establishes the prevalence of such planets in the Solar neighborhood, future missions can be designed to find not just a planet in the Goldilocks Zone but a planet for Goldilocks—a truly habitable environment for life as we know it. Kepler discoveries and progress will be described as well as the resources available to bring Kepler science to the public and into the classroom. The possibility of finding evidence of life beyond Earth is working its way into the public consciousness and has the potential to inspire generations. Scientific literacy is a natural consequence of awakening the spirit of exploration and discovery that led Goldilocks into the forest and leads humans into space.

  4. Planets and satellites: tectonic twins

    NASA Astrophysics Data System (ADS)

    Kochemasov, G. G.

    2015-10-01

    There are only three solid planet-satellite pairs in the Solar system: Earth -Moon, Mars -Phobos, Pluto - Charon. For the first two pairs tectonic analogies were shown and explained by moving them in one circumsolar orbit. As it is known from the wave planetology [3, 4, 6], "orbits make structures". For the third pair the same was stated as a prediction based on this fundamental rule. Global tectonic forms of wave origin appear in cosmic bodies because they move in keplerian orbits with periodically changing accelerations. Warping bodies waves have a stationary character and obeying wave harmonics lengths. Starting from the fundamental 2πR-long wave 1 making the ubiquitous tectonic dichotomy (two-face appearance) warping wave lengths descend along harmonics. Very prominent along with the wave 1 are waves 2 responsible for tectonic sectoring superimposed on the wave 1 segments. Practically all bodies have traces of shorter waves making numerous polygons (rings) often confused with impact craters. Earth and the Moon moving in one circumsolar orbit both are distorted by wave 1, wave 2 and wave 4 features aligned along extent tectonic lines [4, 5]. At Earth they are: Pacific Ocean (2πR-structure) and Indian Ocean (πR-structure) from both ends with Malay Archipelago (πR/4-structure) in the middle. At Moon they are: Procellarum Ocean (2πR) and SPA Basin (πR) from ends and Mare Orientale (πR/4) in the middle. A regular disposition is surprising. Both Oceans and Basin occur on opposite hemispheres, lying in the middle both ring structures occur in the boundary between two hemispheres and are of the same relative size. These triads stretch along lines parallel to the equator (Earth) and with the angle about 30 degrees to it (Moon) indicating at a different orientation of the rotation axes in the ancient time [2]. On the whole, one could speak about a "lunar mould" of Earth [5] (Fig. 1-3). Another tectonic twin is the pair Mars -Phobos. Both bodies sharing one

  5. NASA Reveals Most Unusual Planet

    NASA Video Gallery

    In exploring the universe, NASA has uncovered one planet more unusual than all others. This 30 second video shows you which planet that is, and explains that NASA science helps us better understand...

  6. Finding Planets around other stars

    NASA Video Gallery

    Just as the Earth revolves around the sun, our closest star, other planets might orbit the stars you see in the night sky. Think of all the planets in the universe that may be just the right distan...

  7. THE STRUCTURE OF SURFACE H{sub 2}O LAYERS OF ICE-COVERED PLANETS WITH HIGH-PRESSURE ICE

    SciTech Connect

    Ueta, S.; Sasaki, T. E-mail: takanori@geo.titech.ac.jp

    2013-10-01

    Many extrasolar (bound) terrestrial planets and free-floating (unbound) planets have been discovered. While the existence of bound and unbound terrestrial planets with liquid water is an important question, of particular importance is the question of these planets' habitability. Even for a globally ice-covered planet, geothermal heat from the planetary interior may melt the interior ice, creating an internal ocean covered by an ice shell. In this paper, we discuss the conditions that terrestrial planets must satisfy for such an internal ocean to exist on the timescale of planetary evolution. The question is addressed in terms of planetary mass, distance from a central star, water abundance, and abundance of radiogenic heat sources. In addition, we investigate the structure of the surface H{sub 2}O layers of ice-covered planets by considering the effects of ice under high pressure (high-pressure ice). As a fiducial case, a 1 M{sub ⊕} planet at 1 AU from its central star and with 0.6-25 times the H{sub 2}O mass of the Earth could have an internal ocean. We find that high-pressure ice layers may appear between the internal ocean and the rock portion on a planet with an H{sub 2}O mass over 25 times that of the Earth. The planetary mass and abundance of surface water strongly restrict the conditions under which an extrasolar terrestrial planet may have an internal ocean with no high-pressure ice under the ocean. Such high-pressure ice layers underlying the internal ocean are likely to affect the habitability of the planet.

  8. Ocean worlds exploration

    NASA Astrophysics Data System (ADS)

    Lunine, Jonathan I.

    2017-02-01

    Ocean worlds is the label given to objects in the solar system that host stable, globe-girdling bodies of liquid water-"oceans". Of these, the Earth is the only one to support its oceans on the surface, making it a model for habitable planets around other stars but not for habitable worlds elsewhere in the solar system. Elsewhere in the solar system, three objects-Jupiter's moon Europa, and Saturn's moons Enceladus and Titan-have subsurface oceans whose existence has been detected or inferred by two independent spacecraft techniques. A host of other bodies in the outer solar system are inferred by a single type of observation or by theoretical modeling to have subsurface oceans. This paper focusses on the three best-documented water oceans beyond Earth: those within Europa, Titan and Enceladus. Of these, Europa's is closest to the surface (less than 10 km and possibly less than 1 km in places), and hence potentially best suited for eventual direct exploration. Enceladus' ocean is deeper-5-40 km below its surface-but fractures beneath the south pole of this moon allow ice and gas from the ocean to escape to space where it has been sampled by mass spectrometers aboard the Cassini Saturn Orbiter. Titan's ocean is the deepest-perhaps 50-100 km-and no evidence for plumes or ice volcanism exist on the surface. In terms of the search for evidence of life within these oceans, the plume of ice and gas emanating from Enceladus makes this the moon of choice for a fast-track program to search for life. If plumes exist on Europa-yet to be confirmed-or places can be located where ocean water is extruded onto the surface, then the search for life on this lunar-sized body can also be accomplished quickly by the standards of outer solar system exploration.

  9. Classifying Planets: Nature vs. Nurture

    NASA Astrophysics Data System (ADS)

    Beichman, Charles A.

    2009-05-01

    The idea of a planet was so simple when we learned about the solar system in elementary school. Now students and professional s alike are faced with confusing array of definitions --- from "Brown Dwarfs” to "Super Jupiters", from "Super Earths” to "Terrestrial Planets", and from "Planets” to "Small, Sort-of Round Things That Aren't Really Planets". I will discuss how planets might be defined by how they formed, where they are found, or by the life they might support.

  10. Polarimetry of gas planets

    NASA Astrophysics Data System (ADS)

    Joos, Franco

    The quest for new worlds was not only an adventure at the times of Columbus. Also nowadays mankind searches for new, undiscovered territories. But today they lie no longer only on our Earth, but also well outside the solar system. There, new planets are sought and found. One of the challenges of modern astrophysics is the direct detection of extra- solar planets. To reach this goal, the largest available telescopes and most sophisticated detection techniques are required. A promising method to "see" and analyse extra-solar planets is based on the fact, that light reflected by a planet can be polarised. For its detection, accurate polarisation measurements are needed. This is one of the methods ESO intends to make use of to find new planets outside the solar system. The Institute of Astronomy of ETH Zürich contributes ZIMPOL to this planet-finder project. ZIMPOL is a very sensitive imaging polarimeter. This thesis is situated within the ESO-planet-finder project. It deals with two problems that are crucial for a successful mission: (1) Instrumental polarisation can seriously hamper the performance of the instrument. It is therefore essential, to keep instrumental polarisation very low. (2) A knowledge of the polarisation properties of our targets would be very helpful. For this reason the polarisation properties of our solar system planets are investigated. Promising candidates for a detection with ZIMPOL are large planets with atmospheres similar to those of our giant gas planets Jupiter, Saturn, Uranus and Neptune. In the first part of the thesis the planet-finder project is presented and the role of ZIMPOL is explained. To obtain the instrumental polarisation, the polarimetric properties of mirrors and other optical components of our planet- finder instrument are analysed. The instrumental polarisation for the wavelength range of 600 to 1000 nm and for all zenith distances is calculated with Mueller matrices. Methods for reducing the instrumental polarisation

  11. Extrasolar Planets in the Classroom

    ERIC Educational Resources Information Center

    George, Samuel J.

    2011-01-01

    The field of extrasolar planets is still, in comparison with other astrophysical topics, in its infancy. There have been about 300 or so extrasolar planets detected and their detection has been accomplished by various different techniques. Here we present a simple laboratory experiment to show how planets are detected using the transit technique.…

  12. ALMOST ALL OF KEPLER'S MULTIPLE-PLANET CANDIDATES ARE PLANETS

    SciTech Connect

    Lissauer, Jack J.; Rowe, Jason F.; Bryson, Stephen T.; Howell, Steve B.; Jenkins, Jon M.; Kinemuchi, Karen; Koch, David G.; Marcy, Geoffrey W.; Adams, Elisabeth; Fressin, Francois; Geary, John; Holman, Matthew J.; Ragozzine, Darin; Buchhave, Lars A.; Ciardi, David R.; Fabrycky, Daniel C.; Ford, Eric B.; Morehead, Robert C.; Gilliland, Ronald L.; and others

    2012-05-10

    We present a statistical analysis that demonstrates that the overwhelming majority of Kepler candidate multiple transiting systems (multis) indeed represent true, physically associated transiting planets. Binary stars provide the primary source of false positives among Kepler planet candidates, implying that false positives should be nearly randomly distributed among Kepler targets. In contrast, true transiting planets would appear clustered around a smaller number of Kepler targets if detectable planets tend to come in systems and/or if the orbital planes of planets encircling the same star are correlated. There are more than one hundred times as many Kepler planet candidates in multi-candidate systems as would be predicted from a random distribution of candidates, implying that the vast majority are true planets. Most of these multis are multiple-planet systems orbiting the Kepler target star, but there are likely cases where (1) the planetary system orbits a fainter star, and the planets are thus significantly larger than has been estimated, or (2) the planets orbit different stars within a binary/multiple star system. We use the low overall false-positive rate among Kepler multis, together with analysis of Kepler spacecraft and ground-based data, to validate the closely packed Kepler-33 planetary system, which orbits a star that has evolved somewhat off of the main sequence. Kepler-33 hosts five transiting planets, with periods ranging from 5.67 to 41 days.

  13. How Giant Planets Shape the Characteristics of Terrestrial Planets

    NASA Astrophysics Data System (ADS)

    Barclay, Thomas; Quintana, Elisa V.

    2016-01-01

    The giant planets in the Solar System likely played a defining role in shaping the properties of the Earth and other terrestrial planets during their formation. Observations from the Kepler spacecraft indicate that terrestrial planets are highly abundant. However, there are hints that giant planets a few AU from their stars are not ubiquitous. It therefore seems reasonable to assume that many terrestrial planets lack a Jupiter-like companion. We use a recently developed, state-of-the-art N-body model that allows for collisional fragmentation to perform hundreds of numerical simulations of the final stages of terrestrial planet formation around a Sun-like star -- with and without giant outer planets. We quantify the effects that outer giant planet companions have on collisions and the planet accretion process. We focus on Earth-analogs that form in each system and explore how giant planets influence the relative frequency of giant impacts occurring at late times and the delivery of volitiles. This work has important implications for determining the frequency of habitable planets.

  14. Trojan twin planets

    NASA Astrophysics Data System (ADS)

    Dvorak, R.; Loibnegger, B.; Schwarz, R.

    2017-03-01

    The Trojan asteroids are moving in the vicinity of the stable Lagrange points L_4 and L_5 of the gas giants Jupiter, Uranus and Neptune. Their motion can be described and understood with the aid of the restricted three-body problem. As an extension of this problem we investigate how stable motion close to the Lagrange points of two massive bodies can exist. This configuration can be described as the Trojan Twin Problem when we regard the two additional bodies as having a mass significantly smaller than the the two primary bodies: a star in the center (m_1) and an additional Jupiter-like mass (m_2). Using this 4-body problem we have undertaken numerical investigations concerning possible stable "twin orbits". However, these two bodies (m_3 and m_4) in Trojan-like orbits may have quite different masses. We decided to choose 6 different scenaria for this problem: as primary body, m2, we have taken a Jupiter-like planet, a Saturn-like one, and a super-Earth with 10 Earthmasses (m_{Earth}) respectively. As quasi twin planets, we have used different mass ratios namely objects for m3 and m4 from 10m_{Earth} to Moon like ones. We found different stable configurations depending on the involved masses and the initial distances between the twins (always close to the Lagrange point). Although the formation of such a configuration seems to be not very probable we should not exclude that it exists regarding the huge number of planets even in our own galaxy. This model is of special interest when the most massive planet (m_2) is moving on an orbit in the habitable zone around a main sequence star. One can use our results of stable orbits of Trojan Twin Planets (or asteroids) for extrasolar systems having as second primary a Jupiter-like, a Saturn-like or a super-Earth like planet around a star similar to our Sun.

  15. Archaeoastronomical Concepts in Popular Culture

    NASA Astrophysics Data System (ADS)

    Krupp, Edwin C.

    Broad public embrace of archaic astronomy probably began in the eighteenth century with awareness of the summer solstice sunrise's affiliation with Stonehenge. Since that time, Stonehenge has retained an astronomical mystique that attracts crowds mobilized by the monument's supposed cosmic purpose. They are committed to witness prehistoric heritage operating in real time and with enduring function. More recently, mass media have intermittently thrown a spotlight on new archaeoastronomical discoveries. While the details, ambiguities, and nuances of disciplined study of astronomy in antiquity do not usually infiltrate popular culture, some astronomical alignments, celestial events, sky-tempered symbols, and astral narratives have become well known and referenced in popular culture. Places and relics that command public interest with astronomical connotations are transformed into cultural icons and capture visitors on a quest for the authenticity the past is believed to possess. Monuments and ideas that successfully forge a romantic bond with the past and inspire an imagined sense of sharing the experience, perspective, and wisdom of antiquity persist in the cultural landscape.

  16. Noninsect Arthropods in Popular Music

    PubMed Central

    Coelho, Joseph R.

    2011-01-01

    The occurrence of noninsect arthropods in popular music was examined in order to explore human attitudes toward these species, especially as compared to insects. Crustaceans were the most commonly referenced taxonomic group in artist names, album titles and cover art, followed by spiders and scorpions. The surprising prevalence of crustaceans may be related to the palatability of many of the species. Spiders and scorpions were primarily used for shock value, as well as totemic qualities of strength and ferocity. Spiders were the most abundant group among song titles, perhaps because of their familiarity to the general public. Three noninsect arthropod album titles were found from the early 1970s, then none appear until 1990. Older albums are difficult to find unless they are quite popular, and the resurgence of albums coincides with the rise of the internet. After 1990, issuance of such albums increased approximately linearly. Giant and chimeric album covers were the most common of themes, indicating the use of these animals to inspire fear and surprise. The lyrics of select songs are presented to illustrate the diversity of sentiments present, from camp spookiness to edibility. PMID:26467627

  17. Validating Kepler Planet Candidates

    NASA Astrophysics Data System (ADS)

    Lissauer, Jack J.; Torres, G.; Marcy, G.; Brown, T.; Gilliland, R.; Gautier, T. N.; Isaacson, H.; Dupree, A.; Kepler Science Team

    2011-01-01

    The Kepler Science Team has identified more than 700 transit-like signatures in the first 43 days of data returned from the spacecraft (Borucki et al. 2010, arXiv1006.2799B). However, only 7 of these candidates have been confirmed as planets as of late September 2010. The number of true planets in this sample is clearly far larger than 7, but the sample is also 'contaminated' with false-positives, including many from eclipsing binary stars. Separating the wheat from the chaff requires a careful study of individual candidates using both Kepler photometry and spectroscopic and imaging data from the ground. Techniques that the Science Team is developing to address these issues, which include detailed analysis of the photometric data and follow-up observations with ground-based telescopes, will be presented. Kepler was selected as the 10th mission of the Discovery Program. Funding for this mission is provided by NASA, Science Mission Directorate.

  18. Mission to Planet Earth

    NASA Technical Reports Server (NTRS)

    Wilson, Gregory S.; Backlund, Peter W.

    1992-01-01

    Mission to Planet Earth (MTPE) is NASA's concept for an international science program to produce the understanding needed to predict changes in the Earth's environment. NASA and its interagency and international partners will place satellites carrying advanced sensors in strategic Earth orbits to gather multidisciplinary data. A sophisticated data system will process and archive an unprecedented amount of information about the Earth and how it works as a system. Increased understanding of the Earth system is a basic human responsibility, a prerequisite to informed management of the planet's resources and to the preservation of the global environment. An overview of the MTPE, flight programs, data and information systems, interdisciplinary research efforts, and international coordination, is presented.

  19. Theories of Giant Planet Formation

    NASA Technical Reports Server (NTRS)

    Lissauer, Jack J.; Young, Richard E. (Technical Monitor)

    1998-01-01

    An overview of current theories of planetary formation, with emphasis on giant planets, is presented. The most detailed models are based upon observations of our own Solar System and of young stars and their environments. While these models predict that rocky planets should form around most single stars, the frequency of formation of gas giant planets is more difficult to predict theoretically. Terrestrial planets are believed to grow via pairwise accretion until the spacing of planetary orbits becomes large enough that the configuration is stable for the age of the system. Giant planets begin their growth as do terrestrial planets, but they become massive enough that they are able to accumulate substantial amounts of gas before the protoplanetary disk dissipates. Most models for extrasolar giant planets suggest that they formed as did Jupiter and Saturn (in nearly circular orbits, far enough from the star that ice could), and subsequently migrated to their current positions, although some models suggest in situ formation.

  20. Observed properties of extrasolar planets.

    PubMed

    Howard, Andrew W

    2013-05-03

    Observational surveys for extrasolar planets probe the diverse outcomes of planet formation and evolution. These surveys measure the frequency of planets with different masses, sizes, orbital characteristics, and host star properties. Small planets between the sizes of Earth and Neptune substantially outnumber Jupiter-sized planets. The survey measurements support the core accretion model, in which planets form by the accumulation of solids and then gas in protoplanetary disks. The diversity of exoplanetary characteristics demonstrates that most of the gross features of the solar system are one outcome in a continuum of possibilities. The most common class of planetary system detectable today consists of one or more planets approximately one to three times Earth's size orbiting within a fraction of the Earth-Sun distance.

  1. Pluto: Dwarf planet 134340

    NASA Astrophysics Data System (ADS)

    Ksanfomality, L. V.

    2016-01-01

    In recent decades, investigations of Pluto with up-to-date astronomical instruments yielded results that have been generally confirmed by the New Horizons mission. In 2006, in Prague, the General Assembly of the International Astronomical Union (IAU) reclassified Pluto as a member of the dwarf planet category according to the criteria defined by the IAU for the term "planet". At the same time, interest in studies of Pluto was increasing, while the space investigations of Pluto were delayed. In 2006, the New Horizons Pluto spacecraft started its journey to Pluto. On July 14, 2015, the spacecraft, being in fly-by mode, made its closest approach to Pluto. The heterogeneities and properties of the surface and rarified atmosphere were investigated thoroughly. Due to the extreme remoteness of the spacecraft and the energy limitations, it will take 18 months to transmit the whole data volume. Along with the preliminary results of the New Horizons Pluto mission, this paper reviews the basics on Pluto and its moons acquired from the ground-based observations and with the Hubble Space Telescope (HST). There are only a few meteorite craters on the surfaces of Pluto and Charon, which distinctly marks them apart from such satellites of the giant planets as Ganymede and Callisto. The explanation is that the surface of Pluto is young: its age is estimated at less than 100 Myr. Ice glaciers of apparently a nitrogen nature were found. Nitrogen is also the main component of the atmosphere of Pluto. The planet demonstrates the signs of strong geologic activity, though the energy sources of these processes are unknown.

  2. Planet Forming Protostellar Disks

    NASA Technical Reports Server (NTRS)

    Lubow, Stephen

    1998-01-01

    The project achieved many of its objectives. The main area of investigation was the interaction of young binary stars with surrounding protostellar disks. A secondary objective was the interaction of young planets with their central stars and surrounding disks. The grant funds were used to support visits by coinvestigators and visitors: Pawel Artymowicz, James Pringle, and Gordon Ogilvie. Funds were also used to support travel to meetings by Lubow and to provide partial salary support.

  3. Terrestrial Planet Geophysics

    NASA Astrophysics Data System (ADS)

    Phillips, R. J.

    2008-12-01

    Terrestrial planet geophysics beyond our home sphere had its start arguably in the early 1960s, with Keith Runcorn contending that the second-degree shape of the Moon is due to convection and Mariner 2 flying past Venus and detecting no planetary magnetic field. Within a decade, in situ surface geophysical measurements were carried out on the Moon with the Apollo program, portions of the lunar magnetic and gravity fields were mapped, and Jack Lorell and his colleagues at JPL were producing spherical harmonic gravity field models for Mars using tracking data from Mariner 9, the first spacecraft to orbit another planet. Moreover, Mariner 10 discovered a planetary magnetic field at Mercury, and a young Sean Solomon was using geological evidence of surface contraction to constrain the thermal evolution of the innermost planet. In situ geophysical experiments (such as seismic networks) were essentially never carried out after Apollo, although they were sometimes planned just beyond the believability horizon in planetary mission queues. Over the last three decades, the discipline of terrestrial planet geophysics has matured, making the most out of orbital magnetic and gravity field data, altimetric measurements of surface topography, and the integration of geochemical information. Powerful constraints are provided by tectonic and volcanic information gleaned from surface images, and the engagement of geologists in geophysical exercises is actually quite useful. Accompanying these endeavors, modeling techniques, largely adopted from the Earth Science community, have become increasingly sophisticated and have been greatly enhanced by the dramatic increase in computing power over the last two decades. The future looks bright with exciting new data sets emerging from the MESSENGER mission to Mercury, the promise of the GRAIL gravity mission to the Moon, and the re-emergence of Venus as a worthy target for exploration. Who knows? With the unflagging optimism and persistence

  4. Formation of Giant Planets

    NASA Technical Reports Server (NTRS)

    Lin, Douglas

    1999-01-01

    Under the support of NASA Origins grant, we studied the formation of gaps in protoplanetary disks due the tidal interaction between a fully grown protoplanet and protostellar disk. The result of this study is published in the Astrophysical Journal, (vol 514, 344-367, 1999) and in several conference proceedings. The main focus of this work is to analyze planet-disk interaction during the final stages of protoplanetary formation.

  5. THE STEPPENWOLF: A PROPOSAL FOR A HABITABLE PLANET IN INTERSTELLAR SPACE

    SciTech Connect

    Abbot, D. S.; Switzer, E. R. E-mail: switzer@kicp.uchicago.edu

    2011-07-10

    Rogue planets have been ejected from their planetary system. We investigate the possibility that a rogue planet could maintain a liquid ocean under layers of thermally insulating water ice and frozen gas as a result of geothermal heat flux. We find that a rogue planet of Earth-like composition and age could maintain a subglacial liquid ocean if it were {approx}3.5 times more massive than Earth, corresponding to {approx}8 km of ice. Suppression of the melting point by contaminants, a layer of frozen gas, or a larger complement of water could significantly reduce the planetary mass that is required to maintain a liquid ocean. Such a planet could be detected from reflected solar radiation, and its thermal emission could be characterized in the far-IR if it were to pass within O(1000) AU of Earth.

  6. Extrasolar planet detection

    NASA Technical Reports Server (NTRS)

    Korechoff, R. P.; Diner, D. J.; Tubbs, E. F.; Gaiser, S. L.

    1994-01-01

    This paper discusses the concept of extrasolar planet detection using a large-aperture infared imaging telescope. Coronagraphic stellar apodization techniques are less efficient at infrared wavelengths compared to the visible, as a result of practical limitations on aperture dimensions, thus necessitating additional starlight suppression to make planet detection feasible in this spectral domain. We have been investigating the use of rotational shearing interferometry to provide up to three orders of magnitude of starlight suppression over broad spectral bandwidths. We present a theoretical analysis of the system performance requirements needed to make this a viable instrument for planet detection, including specifications on the interferometer design and telescope aperture characteristics. The concept of using rotational shearing interferometry as a wavefront error detector, thus providing a signal that can be used to adaptively correct the wavefront, will be discussed. We also present the status of laboratory studies of on-axis source suppression using a recently constructed rotational shearing interferometer that currently operates in the visible.

  7. The Gemini Planet Imager

    NASA Astrophysics Data System (ADS)

    Graham, James R.; Macintosh, Bruce; Perrin, Marshall D.; Ingraham, Patrick; Konopacky, Quinn M.; Marois, Christian; Poyneer, Lisa; Bauman, Brian; Barman, Travis; Burrows, Adam Seth; Cardwell, Andrew; Chilcote, Jeffrey K.; De Rosa, Robert John J.; Dillon, Daren; Doyon, Rene; Dunn, Jennifer; Erikson, Darren; Fitzgerald, Michael P.; Gavel, Donald; Goodsell, Stephen J.; Hartung, Markus; Hibon, Pascale; Kalas, Paul; Larkin, James E.; Maire, Jerome; Marchis, Franck; Marley, Mark S.; McBride, James; Millar-Blanchaer, Max; Morzinski, Kathleen M.; Nielsen, Eric L.; Norton, Andew; Oppenheimer, Rebecca; Palmer, David; Patience, Jenny; Pueyo, Laurent; Rantakyro, Fredrik; Sadakuni, Naru; Saddlemeyer, Leslie; Savransky, Dmitry; Serio, Andrew W.; Soummer, Remi; Sivaramakrishnan, Anand; Song, Inseok; Thomas, Sandrine; Wallace, J. Kent; Wang, Jason; Wiktorowicz, Sloane; Wolff, Schulyer; Gpi/Gpies Team

    2015-01-01

    The Gemini Planet Imager (GPI) is a dedicated facility for directly imaging and spectroscopically characterizing extrasolar planets. It combines a very high-order adaptive optics system, a diffraction-suppressing coronagraph, and an integral field spectrograph with low spectral resolution but high spatial resolution. Every aspect of GPI has been tuned for maximum sensitivity to faint planets near bright stars. GPI has undergone a year of commissioning, verification, and calibration work. We have achieved an estimated H-band contrast (5-sigma) of 106 at 0.75 arcseconds and 105 at 0.35 arcseconds in spectral mode, and suppression of unpolarized starlight by a factor of 800 in imaging polarimetry mode. Early science observations include study of the spectra of β Pic b and HR 8799, orbital investigations of β Pic b and PZ Tel, and observations of the debris disk systems associated with β Pic, AU Mic, and HR 4796A. An 890-hour exoplanet survey with GPI is scheduled to begin in late 2014. A status report for the campaign will be presented.

  8. Identifying Obstacles to Incorporating Ocean Content into California Secondary Classrooms

    ERIC Educational Resources Information Center

    Stock, Jennifer

    2010-01-01

    The ocean is the dominant feature on this planet that makes all life on Earth possible. Marine educators and scientists across the country have identified essential principles and concepts that define what an "ocean literate" person should know, but there is a lack of comprehensive ocean content coverage in secondary classrooms across…

  9. PREDICTING PLANETS IN KEPLER MULTI-PLANET SYSTEMS

    SciTech Connect

    Fang, Julia; Margot, Jean-Luc

    2012-05-20

    We investigate whether any multi-planet systems among Kepler candidates (2011 February release) can harbor additional terrestrial-mass planets or smaller bodies. We apply the packed planetary systems hypothesis that suggests all planetary systems are filled to capacity, and use a Hill stability criterion to identify eight two-planet systems with significant gaps between the innermost and outermost planets. For each of these systems, we perform long-term numerical integrations of 10{sup 7} years to investigate the stability of 4000-8000 test particles injected into the gaps. We map out stability regions in orbital parameter space, and therefore quantify the ranges of semimajor axes and eccentricities of stable particles. Strong mean-motion resonances can add additional regions of stability in otherwise unstable parameter space. We derive simple expressions for the extent of the stability regions, which is related to quantities such as the dynamical spacing {Delta}, the separation between two planets in units of their mutual Hill radii. Our results suggest that planets with separation {Delta} < 10 are unlikely to host extensive stability regions, and that about 95 out of a total of 115 two-planet systems in the Kepler sample may have sizeable stability regions. We predict that Kepler candidate systems including KOI 433, KOI 72/Kepler-10, KOI 555, KOI 1596, KOI 904, KOI 223, KOI 1590, and KOI 139 can harbor additional planets or low-mass bodies between the inner and outer detected planets. These predicted planets may be detected by future observations.

  10. Experimental determination of salt partition coefficients between aqueous fluids, ice VI and ice VII: implication for the composition of the deep ocean and the geodynamics of large icy moons and water rich planets

    NASA Astrophysics Data System (ADS)

    Journaux, Baptiste; Daniel, Isabelle; Cardon, Hervé; Petitgirard, Sylvain; Perrillat, Jean-Philippe; Caracas, Razvan; Mezouar, Mohamed

    2015-04-01

    The potential habitability of extraterrestrial large aqueous reservoir in icy moons and exoplanets requires an input of nutrients and chemicals that may come from the rocky part of planetary body. Because of the presence of high pressure (HP) water ices (VI, VII, etc.) between the liquid ocean and the silicates, such interactions are considered to be limited in large icy moons, like Ganymede and Titan, and water rich exoplanets. In the case of salty-rich oceans, recent experimental and modeling works have shown that aqueous fluids can be stable at higher pressures [1, 2]. This can ultimately allow direct interaction with the rocky core of icy moons. This effect is nevertheless limited and for larger bodies such as water rich exoplanets with much higher pressures in their hydrosphere, HP ice should be present between the rocky core and a putative ocean. Salts are highly incompatible with low pressure ice Ih, but recent experimental work has shown that alkali metal and halogen salts are moderately incompatible with ice VII, that can incorporate up to several mol/kg of salts [3, 4, 5]. As far as we know, no similar study has been done on ice VI, a HP ice phase expected inside large icy moons. We present here the first experimental data on the partition coefficient of RbI salt between aqueous fluids, ice VI and ice VII using in-situ synchrotron X-Ray single crystal diffraction and X-Ray fluorescence mapping (ESRF - ID-27 beam line [6]). Our experiment enable us to observe a density inversion between ice VI and the salty fluid, and to measure the values of salt partition coefficients between the aqueous fluid and ice VI (strongly incompatible) and ice VII (moderately incompatible). Using the volumes determined with X-Ray diffraction, we were able to measure the density of salty ice VI and ice VII and determine that salty ice VI is lighter than pure H2O ice VI. These results are very relevant for the study of water rich planetary bodies interior because the partition

  11. Popular education: The Latin American experience

    NASA Astrophysics Data System (ADS)

    Grossi, Francisco Vío

    1985-09-01

    The author discusses the theory and practice of popular education in Latin America, seen as an alternative model for social change at the popular level, rather than simply an educational method. The development of popular education is located in the context of the political-economic history of Latin America, and the consequences of this for the peasantry and the working class. The author presents the defining characteristics of popular education, together with its main tendencies, both negative and positive.

  12. Mass-Radius Relationships for Low-Mass Planets: From Iron Planets to Water Planets

    NASA Technical Reports Server (NTRS)

    Kuchner, Marc

    2007-01-01

    Transit observations, and radial velocity measurements, have begun to populate the mass radius diagram for extrasolar planets; fubture astrometric measurements and direct images promise more mass and radius information. Clearly, the bulk density of a planet indicates something about a planet s composition--but what? I will attempt to answer this question in general for low-mass planets (planets obey a kind of universal mass-radius relationship: an expansion whose first term is M approx. R(sup 3).

  13. The Rocky Planet Survey

    NASA Astrophysics Data System (ADS)

    Fischer, Debra

    In direct support of the NASA Origins program, we propose the Rocky Planet Survey, a high cadence exoplanet search of sixty late G and K dwarf stars using the CHIRON spectrometer, which we built and commissioned at CTIO. CHIRON operates in two high- resolution modes (R=90,000 and R=120,000) and has a demonstrated precision of better than 1 m s-1. We are contributing 200 nights of telescope time for the next three years, for the excellent phase coverage needed to carry out this work. We have developed simulation software to optimize scheduling of observations to suppress aliases and quickly extract dynamical signals. Our science objectives are to (1) provide a statistical assessment of planet occurrence as a function of decreasing mass in the range of parameter space 3 < Msini < 30 MEARTH for orbital periods up to 50 days, (2) to determine the fraction of low mass planets in multi-planet architectures, and (3) detect planets with Msini < 3 MEARTH in orbital periods shorter than ~20 days. In addition to the science objectives, we intend to push the frontiers of extreme precision Doppler measurements to keep the U.S. competitive with the next generation of European Doppler spectroscopy (ESPRESSO on the VLT). Our team has significant expertise in optical design, fiber coupling, raw extraction, barycentric velocity corrections, and Doppler analysis. The proposed work includes a new optimal extraction algorithm, with the optical designers and software engineers working together on the 2-D PSF description needed for a proper row-by-row extraction and calibration. We will also develop and test upgrades to the barycentric correction code and improvements in the Doppler code that take advantage of stability in the dispersion solution, afforded by a new vacuum-enclosed grating upgrade (scheduled for November 2011). We will test use of emission wavelength calibrations to extend the iodine (absorption) wavelength calibration that we currently use to prepare for eventual use of

  14. Communicating meteorology through popular music

    NASA Astrophysics Data System (ADS)

    Brown, Sally; Aplin, Karen; Jenkins, Katie; Mander, Sarah; Walsh, Claire; Williams, Paul

    2015-04-01

    Previous studies of weather-inspired classical music showed that all forms of music (as well as visual arts and literature) reflect the significance of the environment in society. Here we quantify the extent to which weather has inspired popular musicians, and how weather is represented in English-language pop music. Our work is in press at Weather. Over 750 songs have been identified which were found to refer to meteorological phenomena, mainly in their lyrics, but also in the title of the song, name of the band or songwriter and occasionally in the song's music or sound effects. Over one third of the songs analysed referred to either sun or rain, out of a possible 20 weather categories. It was found that artists use weather to describe emotion, for example, to mirror the changes in a relationship. In this context, rain was broadly seen negatively, and might be used to signify the end of a relationship. Rain could also be perceived in a positive way, such as in songs from more agricultural communities. Wind was the next most common weather phenomenon, but did not represent emotions as much as sun or rain. However, it was the most frequently represented weather type in the music itself, such as in instrumental effects, or non-verbally in choruses. From the limited evidence available, we found that artists were often inspired by a single weather event in writing lyrics, whereas the outcomes were less clearly identifiable from longer periods of good or bad weather. Some artists were influenced more by their environment than others, but they were often inspired to write many songs about their surroundings as part of every-day life, rather than weather in particular. Popular singers and songwriters can therefore emotionally connect their listeners to the environment; this could be exploited to communicate environmental science to a broad audience.

  15. Popular Culture in the Junior College Library

    ERIC Educational Resources Information Center

    Lonergan, David; Ayers, Meredith

    2015-01-01

    Popular culture is extremely influential in both academe and society at large. However, formal disciplinary study of popular culture lags far behind that influence. Anthropology, film studies, history, musicology, and sociology are only some of the disciplines that frequently include popular culture as a research focus. This article advises on how…

  16. THE INTERIOR DYNAMICS OF WATER PLANETS

    SciTech Connect

    Fu, Roger; O'Connell, Richard J.; Sasselov, Dimitar D. E-mail: richard_oconnell@harvard.ed

    2010-01-10

    The ever-expanding catalog of detected super-Earths calls for theoretical studies of their properties in the case of a substantial water layer. This work considers such water planets with a range of masses and water mass fractions (2-5 M{sub Earth}, 0.02%-50% H{sub 2}O). First, we model the thermal and dynamical structure of the near-surface for icy and oceanic surfaces, finding separate regimes where the planet is expected to maintain a subsurface liquid ocean and where it is expected to exhibit ice tectonics. Newly discovered exoplanets may be placed into one of these regimes given estimates of surface temperature, heat flux, and gravity. Second, we construct a parameterized convection model for the underlying ice mantle of higher ice phases, finding that materials released from the silicate-iron core should traverse the ice mantle on the timescale of 0.1 to 100 megayears. We present the dependence of the overturn times of the ice mantle and the planetary radius on total mass and water mass fraction. Finally, we discuss the implications of these internal processes on atmospheric observables.

  17. Ocean-sized threats

    NASA Astrophysics Data System (ADS)

    Showstack, Randy

    Jane Lubchenco, professor of marine biology and zoology at Oregon State University, and president-elect of the International Council for Science, said that scientists can do more than they currently are doing to clearly communicate to the public and to policy-makers those issues associated with the many ecological threats faced by the world's oceans. In doing so, scientists can overcome popularly-held misperceptions about the health of the world's oceans and thus, help protect the seas."Science," Lubchenco said, "has a huge role to play in informing [the public] what is happening and to guide the choice of solutions.

  18. Ocean-sized threats

    NASA Astrophysics Data System (ADS)

    Showstack, Randy

    Jane Lubchenco, professor of marine biology and zoology at Oregon State University, and president-elect of the International Council for Science, said that scientists can do more than they currently are doing to clearly communicate to the public and to policy-makers those issues associated with the many ecological threats faced by the world's oceans. In doing so, scientists can overcome popularly-held misperceptions about the health of the world's oceans and thus, help protect the seas.“Science,” Lubchenco said, “has a huge role to play in informing [the public] what is happening and to guide the choice of solutions.

  19. Astrometric Planet Searches with SIM PlanetQuest

    NASA Technical Reports Server (NTRS)

    Beichman, Charles A.; Unwin, Stephen C.; Shao, Michael; Tanner, Angelle M.; Catanzarite, Joseph H.; March, Geoffrey W.

    2007-01-01

    SIM will search for planets with masses as small as the Earth's orbiting in the habitable zones' around more than 100 of the stars and could discover many dozen if Earth-like planets are common. With a planned 'Deep Survey' of 100-450 stars (depending on desired mass sensitivity) SIM will search for terrestrial planets around all of the candidate target stars for future direct detection missions such as Terrestrial Planet Finder and Darwin, SIM's 'Broad Survey' of 2010 stars will characterize single and multiple-planet systems around a wide variety of stellar types, including many now inaccessible with the radial velocity technique. In particular, SIM will search for planets around young stars providing insights into how planetary systems are born and evolve with time.

  20. The Search for Planet Nine

    NASA Astrophysics Data System (ADS)

    Brown, Michael E.; Batygin, Konstantin

    2016-10-01

    We use an extensive suite of numerical simulations to constrain the mass and orbit of Planet Nine, and we use these constraints to begin the search for this newly proposed planet in new and in archival data. Here, we compare our simulations to the observed population of aligned eccentric high semimajor axis Kuiper belt objects and determine which simulation parameters are statistically compatible with the observations. We find that only a narrow range of orbital elements can reproduce the observations. In particular, the combination of semimajor axis, eccentricity, and mass of Planet Nine strongly dictates the semimajor axis range of the orbital confinement of the distant eccentric Kuiper belt objects. Allowed orbits, which confine Kuiper belt objects with semimajor axis beyond 380 AU, have perihelia roughly between 150 and 350 AU, semimajor axes between 380 and 980 AU, and masses between 5 and 20 Earth masses. Orbitally confined objects also generally have orbital planes similar to that of the planet, suggesting that the planet is inclined approximately 30 degrees to the ecliptic. We compare the allowed orbital positions and estimated brightness of Planet Nine to previous and ongoing surveys which would be sensitive to the planet's detection and use these surveys to rule out approximately two-thirds of the planet's orbit. Planet Nine is likely near aphelion with an approximate brightness of 22planet.

  1. Formation of Outer Planets: Overview

    NASA Technical Reports Server (NTRS)

    Lissauer, Jack

    2003-01-01

    An overview of current theories of planetary formation, with emphasis on giant planets is presented. The most detailed models are based upon observation of our own Solar System and of young stars and their environments. Terrestrial planets are believe to grow via pairwise accretion until the spacing of planetary orbits becomes large enough that the configuration is stable for the age of the system. According to the prevailing core instability model, giant planets begin their growth by the accumulation of small solid bodies, as do terrestrial planets. However, unlike terrestrial planets, the growing giant cores become massive enough that they are able to accumulate substantial amounts of gas before the protoplanetary disk disspates. The primary questions regarding the core instability model is whether planets with small cores can accrete gaseous enveloples within the lifetimes of gaseous protoplanetary disks. The main alternative giant planet formation model is the disk instability model, in which gaseous planets form directly via gravitational instabilities within protoplanetary disks. Formation of giant planets via gas instability has never been demonstrated for realistic disk conditions. Moreover, this model has difficulty explaining the supersolar abundances of heavy elements in Jupiter and Saturn, and it does not explain the orgin of planets like Uranus and Neptune.

  2. Taxonomy of the extrasolar planet.

    PubMed

    Plávalová, Eva

    2012-04-01

    When a star is described as a spectral class G2V, we know that the star is similar to our Sun. We know its approximate mass, temperature, age, and size. When working with an extrasolar planet database, it is very useful to have a taxonomy scale (classification) such as, for example, the Harvard classification for stars. The taxonomy has to be easily interpreted and present the most relevant information about extrasolar planets. I propose an extrasolar planet taxonomy scale with four parameters. The first parameter concerns the mass of an extrasolar planet in the form of units of the mass of other known planets, where M represents the mass of Mercury, E that of Earth, N Neptune, and J Jupiter. The second parameter is the planet's distance from its parent star (semimajor axis) described in a logarithm with base 10. The third parameter is the mean Dyson temperature of the extrasolar planet, for which I established four main temperature classes: F represents the Freezing class, W the Water class, G the Gaseous class, and R the Roasters class. I devised one additional class, however: P, the Pulsar class, which concerns extrasolar planets orbiting pulsar stars. The fourth parameter is eccentricity. If the attributes of the surface of the extrasolar planet are known, we are able to establish this additional parameter where t represents a terrestrial planet, g a gaseous planet, and i an ice planet. According to this taxonomy scale, for example, Earth is 1E0W0t, Neptune is 1N1.5F0i, and extrasolar planet 55 Cnc e is 9E-1.8R1.

  3. Optimal Planet Properties For Plate Tectonics Through Time And Space

    NASA Astrophysics Data System (ADS)

    Stamenkovic, Vlada; Seager, Sara

    2014-11-01

    Both the time and the location of planet formation shape a rocky planet’s mass, interior composition and structure, and hence also its tectonic mode. The tectonic mode of a planet can vary between two end-member solutions, plate tectonics and stagnant lid convection, and does significantly impact outgassing and biogeochemical cycles on any rocky planet. Therefore, estimating how the tectonic mode of a planet is affected by a planet’s age, mass, structure, and composition is a major step towards understanding habitability of exoplanets and geophysical false positives to biosignature gases. We connect geophysics to astronomy in order to understand how we could identify and where we could find planet candidates with optimal conditions for plate tectonics. To achieve this goal, we use thermal evolution models, account for the current wide range of uncertainties, and simulate various alien planets. Based on our best model estimates, we predict that the ideal targets for plate tectonics are oxygen-dominated (C/O<1) (solar system like) rocky planets of ~1 Earth mass with surface oceans, large metallic cores super-Mercury, rocky body densities of ~7000kgm-3), and with small mantle concentrations of iron 0%), water 0%), and radiogenic isotopes 10 times less than Earth). Super-Earths, undifferentiated planets, and especially hypothetical carbon planets, speculated to consist of SiC and C, are not optimal for the occurrence of plate tectonics. These results put Earth close to an ideal compositional and structural configuration for plate tectonics. Moreover, the results indicate that plate tectonics might have never existed on planets formed soon after the Big Bang—but instead is favored on planets formed from an evolved interstellar medium enriched in iron but depleted in silicon, oxygen, and especially in Th, K, and U relative to iron. This possibly sets a belated Galactic start for complex Earth-like surface life if plate tectonics significantly impacts the build up

  4. Origin of the atmosphere and hydrosphere of the terrestrial planets

    NASA Technical Reports Server (NTRS)

    Matsui, T.; Abe, Y.

    1985-01-01

    An early thermal evolution of a planet growing by planetesimal impacts was studied. An evolution of an impact induced atmosphere was considered. It is known that the surface of a growing planet is heated due to the blanketing effect of the atmosphere and exceeds the melting temperature, which means that the surface of a growing planet was entirely covered by a magma ocean. The amount of water in a proto-atmosphere is influenced by the formation of a magma ocean. It is suggested the solubility of water in silicate melt controls the water content in a proto-atmsphere. It is noted that irrespective of difference in initial water content of planetesimals the final water content in the atmosphere becomes almost constant and is about 10 to the 21st power kg which is almost identical with the present amount of the ocean. It is also shown that the water in a proto-atmosphere can be liquid for the Earth and becomes to be an ocean but this does not happen on Venus.

  5. Characterizing popularity dynamics of online videos

    NASA Astrophysics Data System (ADS)

    Ren, Zhuo-Ming; Shi, Yu-Qiang; Liao, Hao

    2016-07-01

    Online popularity has a major impact on videos, music, news and other contexts in online systems. Characterizing online popularity dynamics is nature to explain the observed properties in terms of the already acquired popularity of each individual. In this paper, we provide a quantitative, large scale, temporal analysis of the popularity dynamics in two online video-provided websites, namely MovieLens and Netflix. The two collected data sets contain over 100 million records and even span a decade. We characterize that the popularity dynamics of online videos evolve over time, and find that the dynamics of the online video popularity can be characterized by the burst behaviors, typically occurring in the early life span of a video, and later restricting to the classic preferential popularity increase mechanism.

  6. Toward Predicting Popularity of Social Marketing Messages

    NASA Astrophysics Data System (ADS)

    Yu, Bei; Chen, Miao; Kwok, Linchi

    Popularity of social marketing messages indicates the effectiveness of the corresponding marketing strategies. This research aims to discover the characteristics of social marketing messages that contribute to different level of popularity. Using messages posted by a sample of restaurants on Facebook as a case study, we measured the message popularity by the number of "likes" voted by fans, and examined the relationship between the message popularity and two properties of the messages: (1) content, and (2) media type. Combining a number of text mining and statistics methods, we have discovered some interesting patterns correlated to "more popular" and "less popular" social marketing messages. This work lays foundation for building computational models to predict the popularity of social marketing messages in the future.

  7. Remote Sensing of Ocean Color

    NASA Astrophysics Data System (ADS)

    Dierssen, Heidi M.; Randolph, Kaylan

    The oceans cover over 70% of the earth's surface and the life inhabiting the oceans play an important role in shaping the earth's climate. Phytoplankton, the microscopic organisms in the surface ocean, are responsible for half of the photosynthesis on the planet. These organisms at the base of the food web take up light and carbon dioxide and fix carbon into biological structures releasing oxygen. Estimating the amount of microscopic phytoplankton and their associated primary productivity over the vast expanses of the ocean is extremely challenging from ships. However, as phytoplankton take up light for photosynthesis, they change the color of the surface ocean from blue to green. Such shifts in ocean color can be measured from sensors placed high above the sea on satellites or aircraft and is called "ocean color remote sensing." In open ocean waters, the ocean color is predominantly driven by the phytoplankton concentration and ocean color remote sensing has been used to estimate the amount of chlorophyll a, the primary light-absorbing pigment in all phytoplankton. For the last few decades, satellite data have been used to estimate large-scale patterns of chlorophyll and to model primary productivity across the global ocean from daily to interannual timescales. Such global estimates of chlorophyll and primary productivity have been integrated into climate models and illustrate the important feedbacks between ocean life and global climate processes. In coastal and estuarine systems, ocean color is significantly influenced by other light-absorbing and light-scattering components besides phytoplankton. New approaches have been developed to evaluate the ocean color in relationship to colored dissolved organic matter, suspended sediments, and even to characterize the bathymetry and composition of the seafloor in optically shallow waters. Ocean color measurements are increasingly being used for environmental monitoring of harmful algal blooms, critical coastal habitats

  8. Debris Disks and Hidden Planets

    NASA Technical Reports Server (NTRS)

    Kuchner, Marc

    2008-01-01

    When a planet orbits inside a debris disk like the disk around Vega or Beta Pictoris, the planet may be invisible, but the patterns it creates in the disk may give it away. Observing and decoding these patterns may be the only way we can detect exo-Neptunes orbiting more than 20 AU from their stars, and the only way we can spot planets in systems undergoing the late stages of planet formation. Fortunately, every few months, a new image of a debris disk appears with curious structures begging for explanation. I'll describe some new ideas in the theory of these planet-disk interactions and provide a buyers guide to the latest models (and the planets they predict).

  9. Atmospheres of Extrasolar Giant Planets

    NASA Technical Reports Server (NTRS)

    Marley, Mark

    2006-01-01

    The next decade will almost certainly see the direct imaging of extrasolar giant planets around nearby stars. Unlike purely radial velocity detections, direct imaging will open the door to characterizing the atmosphere and interiors of extrasola planets and ultimately provide clues on their formation and evolution through time. This process has already begun for the transiting planets, placing new constraints on their atmospheric structure, composition, and evolution. Indeed the key to understanding giant planet detectability, interpreting spectra, and constraining effective temperature and hence evolution-is the atmosphere. I will review the universe of extrasolar giant planet models, focusing on what we have already learned from modeling and what we will likely be able to learn from the first generation of direct detection data. In addition to these theoretical considerations, I will review the observations and interpretation of the - transiting hot Jupiters. These objects provide a test of our ability to model exotic atmospheres and challenge our current understanding of giant planet evolution.

  10. Planet X - Fact or fiction?

    NASA Technical Reports Server (NTRS)

    Anderson, John

    1988-01-01

    The search for a possible tenth planet in our solar system is examined. The history of the discoveries of Uranus, Neptune, and Pluto are reviewed. Searches of the sky with telescopes and theoretical studies of the gravitational influences on the orbits of known objects in the solar system are discussed. Information obtained during the Pioneer 10 and 11 missions which could suggest the presence of an undiscovered planet and computer simulations of the possible orbit of a tenth planet are presented.

  11. Planet X - ract or fiction

    SciTech Connect

    Anderson, J.

    1988-08-01

    The search for a possible tenth planet in our solar system is examined. The history of the discoveries of Uranus, Neptune, and Pluto are reviewed. Searches of the sky with telescopes and theoretical studies of the gravitational influences on the orbits of known objects in the solar system are discussed. Information obtained during the Pioneer 10 and 11 missions which could suggest the presence of an undiscovered planet and computer simulations of the possible orbit of a tenth planet are presented.

  12. Formation of the giant planets

    NASA Technical Reports Server (NTRS)

    Lissauer, Jack J.

    2006-01-01

    The observed properties of giant planets, models of their evolution and observations of protoplanetary disks provide constraints on the formation of gas giant planets. The four largest planets in our Solar System contain considerable quantities of hydrogen and helium, which could not have condensed into solid planetesimals within the protoplanetary disk. All three (transiting) extrasolar giant planets with well determined masses and radii also must contain substantial amounts of these light gases. Jupiter and Saturn are mostly hydrogen and helium, but have larger abundances of heavier elements than does the Sun. Neptune and Uranus are primarily composed of heavier elements. HD 149026 b, which is slightly more massive than is Saturn, appears to have comparable quantities of light gases and heavy elements. HD 209458 b and TrES-1 are primarily hydrogen and helium, but may contain supersolar abundances of heavy elements. Spacecraft flybys and observations of satellite orbits provide estimates of the gravitational moments of the giant planets in our Solar System, which in turn provide information on the internal distribution of matter within Jupiter, Saturn, Uranus and Neptune. Atmospheric thermal structure and heat flow measurements constrain the interior temperatures of planets. Internal processes may cause giant planets to become more compositionally differentiated or alternatively more homogeneous; high-pressure laboratory .experiments provide data useful for modeling these processes. The preponderance of evidence supports the core nucleated gas accretion model. According to this model, giant planets begin their growth by the accumulation of small solid bodies, as do terrestrial planets. However, unlike terrestrial planets, the growing giant planet cores become massive enough that they are able to accumulate substantial amounts of gas before the protoplanetary disk dissipates. The primary questions regarding the core nucleated growth model is under what conditions

  13. Starting a Planet Protectors Club

    ERIC Educational Resources Information Center

    US Environmental Protection Agency, 2007

    2007-01-01

    If your mission is to teach children how to reduce, reuse, and recycle waste and create the next generation of Planet Protectors, perhaps leading a Planet Protectors Club is part of your future challenges. You don't have to be an expert in waste reduction and recycling to lead a a Planet Protectors Club. You don't even have to be a teacher. You do…

  14. [Seguro popular: achievements and perspectives].

    PubMed

    Chertorivski-Woldenberg, Salomón

    2011-01-01

    Healthcare systems are organized following one of two basic models: social security systems, which link access to health services to labor status, and national health systems, which grant access to health as a citizen's right. Mexico adopted, since the institutionalization of social security and healthcare services in 1943, a mixed system. Social security institutions covered the salaried workers and public assistance was granted to the remaining of the population. At the beginning of the XXI century the Mexican health system entered a crisis as the conditions to expand health coverage through social security were not met and public assistance services were insufficient. In order to address these developments, the Healthcare Social Protection System was founded (2004) as a mechanism to effectively guarantee every person's right to health as established after the constitutional amendment of article fourth in 1983. Seguro Popular is the mechanism that through federal and states' contributions seeks to financially protect the population without access to social security's health services, and thus prevent impoverishment due to out of pocket and catastrophic health expenditures.

  15. Stars and Planets

    NASA Astrophysics Data System (ADS)

    Neta, Miguel

    2014-05-01

    'Estrelas e Planetas' (Stars and Planets) project was developed during the academic year 2009/2010 and was tested on three 3rd grade classes of one school in Quarteira, Portugal. The aim was to encourage the learning of science and the natural and physical phenomena through the construction and manipulation of materials that promote these themes - in this case astronomy. Throughout the project the students built a small book containing three themes of astronomy: differences between stars and planets, the solar system and the phases of the Moon. To each topic was devoted two sessions of about an hour each: the first to teach the theoretical aspects of the theme and the second session to assembly two pages of the book. All materials used (for theoretical sessions and for the construction of the book) and videos of the finished book are available for free use in www.miguelneta.pt/estrelaseplanetas. So far there is only a Portuguese version but soon will be published in English as well. This project won the Excellency Prize 2011 of Casa das Ciências, a portuguese site for teachers supported by the Calouste Gulbenkian Fundation (www.casadasciencias.org).

  16. Four-planet meteorology

    NASA Technical Reports Server (NTRS)

    1979-01-01

    All planets with atmospheres have common characteristics which are helpful in understanding weather and climate on earth. Of the terrestrial planets, Mars displays the most earth-like characteristics. The feedback mechanism of the Martian Great Dust Storms may control climate on a global scale and shows some parallels to the water cycle on the earth. Venus, on the other hand, has atmosphere motions and characteristics far different from those of earth but appears to be valuable for comparative meteorology and it seems to be a simple weather machine due to absence of axial tilt. A completely gaseous Jupiter also can help because its atmosphere, driven by internal heat, flows round-and-round, showing the same general patterns for years at a time. Results of studying extraterrestrial atmospheres are most important for understanding earth's multi-year weather cycles such as the droughts in the American West every 22 years or effects of the Little Ice Age (1450-1915) on agriculture in the North Hemisphere.

  17. Water-rich planets: How habitable is a water layer deeper than on Earth?

    NASA Astrophysics Data System (ADS)

    Noack, L.; Höning, D.; Rivoldini, A.; Heistracher, C.; Zimov, N.; Journaux, B.; Lammer, H.; Van Hoolst, T.; Bredehöft, J. H.

    2016-10-01

    Water is necessary for the origin and survival of life as we know it. In the search for life-friendly worlds, water-rich planets therefore are obvious candidates and have attracted increasing attention in recent years. The surface H2O layer on such planets (containing a liquid water ocean and possibly high-pressure ice below a specific depth) could potentially be hundreds of kilometres deep depending on the water content and the evolution of the proto-atmosphere. We study possible constraints for the habitability of deep water layers and introduce a new habitability classification relevant for water-rich planets (from Mars-size to super-Earth-size planets). A new ocean model has been developed that is coupled to a thermal evolution model of the mantle and core. Our interior structure model takes into account depth-dependent thermodynamic properties and the possible formation of high-pressure ice. We find that heat flowing out of the silicate mantle can melt an ice layer from below (in some cases episodically), depending mainly on the thickness of the ocean-ice shell, the mass of the planet, the surface temperature and the interior parameters (e.g. radioactive mantle heat sources). The high pressure at the bottom of deep water-ice layers could also impede volcanism at the water-mantle boundary for both stagnant lid and plate tectonics silicate shells. We conclude that water-rich planets with a deep ocean, a large planet mass, a high average density or a low surface temperature are likely less habitable than planets with an Earth-like ocean.

  18. The Role of Popularity Goal in Early Adolescents' Behaviors and Popularity Status

    ERIC Educational Resources Information Center

    Dawes, Molly; Xie, Hongling

    2014-01-01

    The effect of popularity goal on the use of 3 popularity-related behaviors and later popularity status was examined in a diverse sample of 314 6th-grade students (176 girls and 138 boys) in both fall (Time 1) and spring (Time 2) semesters. Popularity goal and the use of popularity-driven behaviors (e.g., "I change the way I dress in order to…

  19. NASA's Terrestrial Planet Finder: The Search for (Habitable) Planets

    NASA Technical Reports Server (NTRS)

    Beichman, C.

    1999-01-01

    One of the primary goals of NASA's Origins program is the search for habitable planets. I will describe how the Terrestrial Planet Finder (TPF) will revolutionize our understanding of the origin and evolution of planetary systems, and possibly even find signs of life beyond the Earth.

  20. NASA's terrestial planet finder: the search for (habitable) planets

    NASA Technical Reports Server (NTRS)

    Beichman, C. A.

    2000-01-01

    One of the primary goals of NASA's Origins program is the search for hospitable planets. I will describe how the Terrestrial Planet Finder (TPF) will revolutionize our understanding of the origin and evolution of planetary systems, and possibly even find signs of life beyond Earth.

  1. Inside-out planet formation

    SciTech Connect

    Chatterjee, Sourav; Tan, Jonathan C. E-mail: jt@astro.ufl.edu

    2014-01-01

    The compact multi-transiting planet systems discovered by Kepler challenge planet formation theories. Formation in situ from disks with radial mass surface density, Σ, profiles similar to the minimum mass solar nebula but boosted in normalization by factors ≳ 10 has been suggested. We propose that a more natural way to create these planets in the inner disk is formation sequentially from the inside-out via creation of successive gravitationally unstable rings fed from a continuous stream of small (∼cm-m size) 'pebbles', drifting inward via gas drag. Pebbles collect at the pressure maximum associated with the transition from a magnetorotational instability (MRI)-inactive ('dead zone') region to an inner MRI-active zone. A pebble ring builds up until it either becomes gravitationally unstable to form an ∼1 M {sub ⊕} planet directly or induces gradual planet formation via core accretion. The planet may undergo Type I migration into the active region, allowing a new pebble ring and planet to form behind it. Alternatively, if migration is inefficient, the planet may continue to accrete from the disk until it becomes massive enough to isolate itself from the accretion flow. A variety of densities may result depending on the relative importance of residual gas accretion as the planet approaches its isolation mass. The process can repeat with a new pebble ring gathering at the new pressure maximum associated with the retreating dead-zone boundary. Our simple analytical model for this scenario of inside-out planet formation yields planetary masses, relative mass scalings with orbital radius, and minimum orbital separations consistent with those seen by Kepler. It provides an explanation of how massive planets can form with tightly packed and well-aligned system architectures, starting from typical protoplanetary disk properties.

  2. Topics in Extrasolar Planet Characterization

    NASA Astrophysics Data System (ADS)

    Howe, Alex Ryan

    I present four papers exploring different topics in the area of characterizing the atmospheric and bulk properties of extrasolar planets. In these papers, I present two new codes, in various forms, for modeling these objects. A code to generate theoretical models of transit spectra of exoplanets is featured in the first paper and is refined and expanded into the APOLLO code for spectral modeling and parameter retrieval in the fourth paper. Another code to model the internal structure and evolution of planets is featured in the second and third papers. The first paper presents transit spectra models of GJ 1214b and other super-Earth and mini-Neptune type planets--planets with a "solid", terrestrial composition and relatively small planets with a thick hydrogen-helium atmosphere, respectively--and fit them to observational data to estimate the atmospheric compositions and cloud properties of these planets. The second paper presents structural models of super-Earth and mini-Neptune type planets and estimates their bulk compositions from mass and radius estimates. The third paper refines these models with evolutionary calculations of thermal contraction and ultraviolet-driven mass loss. Here, we estimate the boundaries of the parameter space in which planets lose their initial hydrogen-helium atmospheres completely, and we also present formation and evolution scenarios for the planets in the Kepler-11 system. The fourth paper uses more refined transit spectra models, this time for hot jupiter type planets, to explore the methods to design optimal observing programs for the James Webb Space Telescope to quantitatively measure the atmospheric compositions and other properties of these planets.

  3. Water Loss from Terrestrial Planets with CO2-rich Atmospheres

    NASA Astrophysics Data System (ADS)

    Wordsworth, R. D.; Pierrehumbert, R. T.

    2013-12-01

    Water photolysis and hydrogen loss from the upper atmospheres of terrestrial planets is of fundamental importance to climate evolution but remains poorly understood in general. Here we present a range of calculations we performed to study the dependence of water loss rates from terrestrial planets on a range of atmospheric and external parameters. We show that CO2 can only cause significant water loss by increasing surface temperatures over a narrow range of conditions, with cooling of the middle and upper atmosphere acting as a bottleneck on escape in other circumstances. Around G-stars, efficient loss only occurs on planets with intermediate CO2 atmospheric partial pressures (0.1-1 bar) that receive a net flux close to the critical runaway greenhouse limit. Because G-star total luminosity increases with time but X-ray and ultraviolet/ultravoilet luminosity decreases, this places strong limits on water loss for planets like Earth. In contrast, for a CO2-rich early Venus, diffusion limits on water loss are only important if clouds caused strong cooling, implying that scenarios where the planet never had surface liquid water are indeed plausible. Around M-stars, water loss is primarily a function of orbital distance, with planets that absorb less flux than ~270 W m-2 (global mean) unlikely to lose more than one Earth ocean of H2O over their lifetimes unless they lose all their atmospheric N2/CO2 early on. Because of the variability of H2O delivery during accretion, our results suggest that many "Earth-like" exoplanets in the habitable zone may have ocean-covered surfaces, stable CO2/H2O-rich atmospheres, and high mean surface temperatures.

  4. Planets and Life

    NASA Astrophysics Data System (ADS)

    Sullivan, Woodruff T., III; Baross, John

    2007-09-01

    Foreword; Preface; Contributors; Prologue; Part I. History: 1. History of astrobiological ideas W. T. Sullivan and D. Carney; 2. From exobiology to astrobiology S. J. Dick; Part II. The Physical Stage: 3. Formation of Earth-like habitable planets D. E. Brownlee and M. Kress; 4. Planetary atmospheres and life D. Catling and J. F. Kasting; Part III. The Origin of Life on Earth: 5. Does 'life' have a definition? C.E. Cleland and C. F. Chyba; 6. Origin of life: crucial issues R. Shapiro; 7. Origin of proteins and nucleic acids A. Ricardo and S. A. Benner; 8. The roots of metabolism G.D. Cody and J. H. Scott; 9. Origin of cellular life D. W. Deamer; Part IV. Life on Earth: 10. Evolution: a defining feature of life J. A. Baross; 11. Evolution of metabolism and early microbial communities J. A. Leigh, D. A. Stahl and J. T. Staley; 12. The earliest records of life on Earth R. Buick; 13. The origin and diversification of eukaryotes M. L. Sogin, D. J. Patterson and A. McArthur; 14. Limits of carbon life on Earth and elsewhere J. A. Baross, J. Huber and M. Schrenk; 15. Life in ice J. W. Deming and H. Eicken; 16. The evolution and diversification of life S. Awramik and K. J. McNamara; 17. Mass extinctions P. D. Ward; Part V. Potentially Habitable Worlds: 18. Mars B. M. Jakosky, F. Westall and A. Brack; 19. Europa C. F. Chyba and C. B. Phillips; 20. Titan J. I. Lunine and B. Rizk; 21. Extrasolar planets P. Butler; Part VI. Searching for Extraterrestrial Life: 22. How to search for life on other worlds C. P. McKay; 23. Instruments and strategies for detecting extraterrestrial life P. G. Conrad; 24. Societial and ethical concerns M. S. Race; 25. Planetary protection J. D. Rummel; 26. Searching for extraterrestrial intelligence J. C. Tarter; 27. Alien biochemistries P. D. Ward and S. A. Benner; Part VII. Future of the Field: 28. Disciplinary and educational opportunities L. Wells, J. Armstrong and J. Huber; Epilogue C. F. Chyba; Appendixes: A. Units and usages; B. Planetary

  5. The earth as a planet - Paradigms and paradoxes

    NASA Technical Reports Server (NTRS)

    Anderson, D. L.

    1984-01-01

    The independent growth of the various branches of the earth sciences in the past two decades has led to a divergence of geophysical, geochemical, geological, and planetological models for the composition and evolution of a terrestrial planet. Evidence for differentiation and volcanism on small planets and a magma ocean on the moon contrasts with hypotheses for a mostly primitive, still undifferentiated, and homogeneous terrestrial mantle. In comparison with the moon, the earth has an extraordinarily thin crust. The geoid, which should reflect convection in the mantle, is apparently unrelated to the current distribution of continents and oceanic ridges. If the earth is deformable, the whole mantle should wander relative to the axis of rotation, but the implications of this are seldom discussed. The proposal of a mantle rich in olivine violates expectations based on evidence from extraterrestrial sources. These and other paradoxes force a reexamination of some long-held assumptions.

  6. Migration of accreting giant planets

    NASA Astrophysics Data System (ADS)

    Crida, A.; Bitsch, B.; Raibaldi, A.

    2016-12-01

    We present the results of 2D hydro simulations of giant planets in proto-planetary discs, which accrete gas at a more or less high rate. First, starting from a solid core of 20 Earth masses, we show that as soon as the runaway accretion of gas turns on, the planet is saved from type I migration : the gap opening mass is reached before the planet is lost into its host star. Furthermore, gas accretion helps opening the gap in low mass discs. Consequently, if the accretion rate is limited to the disc supply, then the planet is already inside a gap and in type II migration. We further show that the type II migration of a Jupiter mass planet actually depends on its accretion rate. Only when the accretion is high do we retrieve the classical picture where no gas crosses the gap and the planet follows the disc spreading. These results impact our understanding of planet migration and planet population synthesis models. The e-poster presenting these results in French can be found here: L'e-poster présentant ces résultats en français est disponible à cette adresse: http://sf2a.eu/semaine-sf2a/2016/posterpdfs/156_179_49.pdf.

  7. The fate of scattered planets

    SciTech Connect

    Bromley, Benjamin C.; Kenyon, Scott J. E-mail: skenyon@cfa.harvard.edu

    2014-12-01

    As gas giant planets evolve, they may scatter other planets far from their original orbits to produce hot Jupiters or rogue planets that are not gravitationally bound to any star. Here, we consider planets cast out to large orbital distances on eccentric, bound orbits through a gaseous disk. With simple numerical models, we show that super-Earths can interact with the gas through dynamical friction to settle in the remote outer regions of a planetary system. Outcomes depend on planet mass, the initial scattered orbit, and the evolution of the time-dependent disk. Efficient orbital damping by dynamical friction requires planets at least as massive as the Earth. More massive, longer-lived disks damp eccentricities more efficiently than less massive, short-lived ones. Transition disks with an expanding inner cavity can circularize orbits at larger distances than disks that experience a global (homologous) decay in surface density. Thus, orbits of remote planets may reveal the evolutionary history of their primordial gas disks. A remote planet with an orbital distance ∼100 AU from the Sun is plausible and might explain correlations in the orbital parameters of several distant trans-Neptunian objects.

  8. Pluto: The Farthest Planet (Usually).

    ERIC Educational Resources Information Center

    Universe in the Classroom, 1988

    1988-01-01

    Provides background information about the planet Pluto. Includes the history of Pluto and discusses some of the common misconceptions about the planets. Addresses some of the recent discoveries about Pluto and contains a resource list of books, articles, and a videotape. (TW)

  9. THREE PLANETS ORBITING WOLF 1061

    SciTech Connect

    Wright, D. J.; Wittenmyer, R. A.; Tinney, C. G.; Bentley, J. S.; Zhao, Jinglin

    2016-02-01

    We use archival HARPS spectra to detect three planets orbiting the M3 dwarf Wolf 1061 (GJ 628). We detect a 1.36 M{sub ⊕} minimum-mass planet with an orbital period P = 4.888 days (Wolf 1061b), a 4.25 M{sub ⊕} minimum-mass planet with orbital period P = 17.867 days (Wolf 1061c), and a likely 5.21 M{sub ⊕} minimum-mass planet with orbital period P = 67.274 days (Wolf 1061d). All of the planets are of sufficiently low mass that they may be rocky in nature. The 17.867 day planet falls within the habitable zone for Wolf 1061 and the 67.274 day planet falls just outside the outer boundary of the habitable zone. There are no signs of activity observed in the bisector spans, cross-correlation FWHMs, calcium H and K indices, NaD indices, or Hα indices near the planetary periods. We use custom methods to generate a cross-correlation template tailored to the star. The resulting velocities do not suffer the strong annual variation observed in the HARPS DRS velocities. This differential technique should deliver better exploitation of the archival HARPS data for the detection of planets at extremely low amplitudes.

  10. WATER TRAPPING ON TIDALLY LOCKED TERRESTRIAL PLANETS REQUIRES SPECIAL CONDITIONS

    SciTech Connect

    Yang, Jun; Abbot, Dorian S.; Liu, Yonggang; Hu, Yongyun

    2014-12-01

    Surface liquid water is essential for standard planetary habitability. Calculations of atmospheric circulation on tidally locked planets around M stars suggest that this peculiar orbital configuration lends itself to the trapping of large amounts of water in kilometers-thick ice on the night side, potentially removing all liquid water from the day side where photosynthesis is possible. We study this problem using a global climate model including coupled atmosphere, ocean, land, and sea ice components as well as a continental ice sheet model driven by the climate model output. For a waterworld, we find that surface winds transport sea ice toward the day side and the ocean carries heat toward the night side. As a result, nightside sea ice remains O(10 m) thick and nightside water trapping is insignificant. If a planet has large continents on its night side, they can grow ice sheets O(1000 m) thick if the geothermal heat flux is similar to Earth's or smaller. Planets with a water complement similar to Earth's would therefore experience a large decrease in sea level when plate tectonics drives their continents onto the night side, but would not experience complete dayside dessiccation. Only planets with a geothermal heat flux lower than Earth's, much of their surface covered by continents, and a surface water reservoir O(10%) of Earth's would be susceptible to complete water trapping.

  11. ESA's Living Planet Programme: The Earth Explorers

    NASA Astrophysics Data System (ADS)

    Achache, J.

    2003-04-01

    The European Space Agency's (ESA's) Living Planet Programme marks the beginning of a new chapter in European led Earth Observation, based on focussed science user-driven missions. The Earth Explorer missions seek to advance the understanding of complex Earth system processes in the atmosphere, hydrosphere, cryosphere, lithosphere, and biosphere. Each of the Explorer missions is adapted to address a specific scientific problem whilst at the same time building on the heritage of, and the experience gained from a decade of successful continuous scientific obervations made by the larger ERS-1, and -2 and Envisat missions. The Living Planet Programme's Explorer line of smaller and focused missions is also complemented by a parallel line of applications-driven Earth Watch missions address mature operational applications and the provision of services. Specifically, the science-driven Explorer missions are designed to further the demonstration of new satellite-based observing techniques that will allow us to develop our knowledge of the Earth system. Four new missions are currently under development, that will soon begin a sequence of launches beginning in 2004 with CryoSat. Several new mission concepts are also undergoing detailed study, with subsequent consideration for approval. The existing approved missions seek to measure: climate-induced changes in polar terrestrial and sea ice masses; a high resolution Earth gravity field; vertical wind vector profiles; and soil moisture and ocean salinity. Mission concepts under study address a broad array of Earth processes from Earth's magnetic field through stratospheric chemistry to terrestrial vegetation. The Explorers employ a wide array of technologies such as lidars for the sensing of clouds, winds, water vapour and other atmospheric constituents; radars for ice and ocean topography, land and ocean monitoring, cloud profiling and rain monitoring; passive instruments covering the UV through far infrared, including

  12. New Indivisible Planetary Science Paradigm: Consequence of Questioning Popular Paradigms

    NASA Astrophysics Data System (ADS)

    Marvin Herndon, J.

    2014-05-01

    Progress in science involves replacing less precise understanding with more precise understanding. In science and in science education one should always question popular ideas; ask "What's wrong with this picture?" Finding limitations, conflicts or circumstances that require special ad hoc consideration sometimes is the key to making important discoveries. For example, from thermodynamic considerations, I found that the 'standard model of solar system formation' leads to insufficiently massive planetary cores. That understanding led me to discover a new indivisible planetary science paradigm. Massive-core planets formed by condensing and raining-out from within giant gaseous protoplanets at high pressures and high temperatures, accumulating heterogeneously on the basis of volatility with liquid core-formation preceding mantle-formation; the interior states of oxidation resemble that of the Abee enstatite chondrite. Core-composition was established during condensation based upon the relative solubilities of elements, including uranium, in liquid iron in equilibrium with an atmosphere of solar composition at high pressures and high temperatures. Uranium settled to the central region and formed planetary nuclear fission reactors, producing heat and planetary magnetic fields. Earth's complete condensation included a ~300 Earth-mass gigantic gas/ice shell that compressed the rocky kernel to about 66% of Earth's present diameter. T-Tauri eruptions, associated with the thermonuclear ignition of the Sun, stripped the gases away from the Earth and the inner planets. The T-Tauri outbursts stripped a portion of Mercury's incompletely condensed protoplanet and transported it to the region between Mars and Jupiter where it fused with in-falling oxidized condensate from the outer regions of the Solar System, forming the parent matter of ordinary chondrite meteorites, the main-Belt asteroids, and veneer for the inner planets, especially Mars. With its massive gas/ice shell

  13. Searching for Planets Around Pulsars

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2015-09-01

    Did you know that the very first exoplanets ever confirmed were found around a pulsar? The precise timing measurements of pulsar PSR 1257+12 were what made the discovery of its planetary companions possible. Yet surprisingly, though weve discovered thousands of exoplanets since then, only one other planet has ever been confirmed around a pulsar. Now, a team of CSIRO Astronomy and Space Science researchers are trying to figure out why.Formation ChallengesThe lack of detected pulsar planets may simply reflect the fact that getting a pulsar-planet system is challenging! There are three main pathways:The planet formed before the host star became a pulsar which means it somehow survived its star going supernova (yikes!).The planet formed elsewhere and was captured by the pulsar.The planet formed out of the debris of the supernova explosion.The first two options, if even possible, are likely to be rare occurrences but the third option shows some promise. In this scenario, after the supernova explosion, a small fraction of the material falls back toward the stellar remnant and is recaptured, forming what is known as a supernova fallback disk. According to this model, planets could potentially form out of this disk.Disk ImplicationsLed by Matthew Kerr, the CSIRO astronomers set out to systematically look for these potential planets that might have formed in situ around pulsars. They searched a sample of 151 young, energetic pulsars, scouring seven years of pulse time-of-arrival data for periodic variation that could signal the presence of planetary companions. Their methods to mitigate pulsar timing noise and model realistic orbits allowed them to have good sensitivity to low-mass planets.The results? They found no conclusive evidence that any of these pulsars have planets.This outcome carries with it some significant implications. The pulsar sample spans 2 Myr in age, in which planets should have had enough time to form in debris disks. The fact that none were detected

  14. Binary Minor Planets

    NASA Astrophysics Data System (ADS)

    Richardson, Derek C.; Walsh, Kevin J.

    2006-05-01

    A review of observations and theories regarding binary asteroids and binary trans-Neptunian objects [collectively, binary minor planets (BMPs)] is presented. To date, these objects have been discovered using a combination of direct imaging, lightcurve analysis, and radar. They are found throughout the Solar System, and present a challenge for theorists modeling their formation in the context of Solar System evolution. The most promising models invoke rotational disruption for the smallest, shortest-lived objects (the asteroids nearest to Earth), consistent with the observed fast rotation of these bodies; impacts for the larger, longer-lived asteroids in the main belt, consistent with the range of size ratios of their components and slower rotation rates; and mutual capture for the distant, icy, trans-Neptunian objects, consistent with their large component separations and near-equal sizes. Numerical simulations have successfully reproduced key features of the binaries in the first two categories; the third remains to be investigated in detail.

  15. New Martian paradigms. [concerning planet's nature and evolution

    NASA Technical Reports Server (NTRS)

    Mcewen, Alfred S.

    1991-01-01

    Several interrelated paradigms concerning the nature and the evolution of Mars are discussed. These include an impact origin of the northern lowland, Mars as a water-rich planet, former oceans in the northern lowlands, a warm wet climate on early Mars, and the possibility of ancient life on Mars. Locations on Mars suggested for the search of possible ancient life include the heavily cratered terrain dissected by valley networks, possible lacustrine deposits in Valles Marineris, the oxidizing layer below the surface, sites along the fringes of the hypothetical northern circumpolar ocean, and in evaporite deposits.

  16. Atmospheres of Extrasolar Giant Planets

    NASA Astrophysics Data System (ADS)

    Marley, M. S.; Fortney, J.; Seager, S.; Barman, T.

    The key to understanding an extrasolar giant planet's spectrum - and hence its detectability and evolution - lies with its atmosphere. Now that direct observations of thermal emission from extrasolar giant planets (EGPs) are in hand, atmosphere models can be used to constrain atmospheric composition, thermal structure, and ultimately the formation and evolution of detected planets. We review the important physical processes that influence the atmospheric structure and evolution of EGPs and consider what has already been learned from the first generation of observations and modeling. We pay particular attention to the roles of cloud structure, metallicity, and atmospheric chemistry in affecting detectable properties through Spitzer Space Telescope observations of the transiting giant planets. Our review stresses the uncertainties that ultimately limit our ability to interpret EGP observations. Finally we will conclude with a look to the future as characterization of multiple individual planets in a single stellar system leads to the study of comparative planetary architectures.

  17. Observational Constraints on Planet Nine

    NASA Astrophysics Data System (ADS)

    Payne, Matthew John; Holman, Matthew J.

    2016-10-01

    Recent publications from Batygin & Brown have rekindled interest in the possibility that there is a large (~10 Earth-Mass) planet lurking unseen in a distant (a~500 AU) orbit at the edge of the Solar System. Such a massive planet would tidally distort the orbits of the other planets in the Solar System.These distortions can potentially be measured and/or constrained through precise observations of the orbits of the outer planets and distant trans-Neptunian objects. I will discuss our recent (and ongoing) attempts to observationally constrain the possible location of Planet Nine via (a) measurements of the orbit of Pluto, and (b) measurements of the orbit of Saturn derived from the Cassini spacecraft.

  18. Why are Pulsar Planets Rare?

    NASA Astrophysics Data System (ADS)

    Martin, Rebecca G.; Livio, Mario; Palaniswamy, Divya

    2016-12-01

    Pulsar timing observations have revealed planets around only a few pulsars. We suggest that the rarity of these planets is due mainly to two effects. First, we show that the most likely formation mechanism requires the destruction of a companion star. Only pulsars with a suitable companion (with an extreme mass ratio) are able to form planets. Second, while a dead zone (a region of low turbulence) in the disk is generally thought to be essential for planet formation, it is most probably rare in disks around pulsars, because of the irradiation from the pulsar. The irradiation strongly heats the inner parts of the disk, thus pushing the inner boundary of the dead zone out. We suggest that the rarity of pulsar planets can be explained by the low probability for these two requirements to be satisfied: a very low-mass companion and a dead zone.

  19. Formation of Planets around Pulsars

    NASA Astrophysics Data System (ADS)

    Banit, M.; Ruderman, M. A.; Shaham, J.; Applegate, J. H.

    1993-10-01

    Pulse arrival-time delays PSR 1257+ 12 suggest the existence of at least two planets in nearly circular orbits around it. In this paper we discuss different scenarios for the formation of planets in circular orbits around pulsars. Among other topics, we look in some detail at wind emission mechanisms that are particularly relevant to the process of evaporation of planets around pulsars and discuss their possible role in orbit circularization. We conclude that the formation of such planets may occur in a very late phase of low-mass X-ray binary (LMXB) or binary millisecond pulsar (BMP) evolution. Evaporation of the companion star in these phases supplies matter to a circumbinary "excretion" disk in which the physical conditions, similar to those appropriate for the BMP 1957+20 system, may allow the formation of planets like those observed in PSR 1257+12.

  20. Highly inclined and eccentric massive planets. II. Planet-planet interactions during the disc phase

    NASA Astrophysics Data System (ADS)

    Sotiriadis, Sotiris; Libert, Anne-Sophie; Bitsch, Bertram; Crida, Aurélien

    2017-02-01

    Context. Observational evidence indicates that the orbits of extrasolar planets are more various than the circular and coplanar ones of the solar system. Planet-planet interactions during migration in the protoplanetary disc have been invoked to explain the formation of these eccentric and inclined orbits. However, our companion paper (Paper I) on the planet-disc interactions of highly inclined and eccentric massive planets has shown that the damping induced by the disc is significant for a massive planet, leading the planet back to the midplane with its eccentricity possibly increasing over time. Aims: We aim to investigate the influence of the eccentricity and inclination damping due to planet-disc interactions on the final configurations of the systems, generalizing previous studies on the combined action of the gas disc and planet-planet scattering during the disc phase. Methods: Instead of the simplistic K-prescription, our N-body simulations adopt the damping formulae for eccentricity and inclination provided by the hydrodynamical simulations of our companion paper. We follow the orbital evolution of 11 000 numerical experiments of three giant planets in the late stage of the gas disc, exploring different initial configurations, planetary mass ratios and disc masses. Results: The dynamical evolutions of the planetary systems are studied along the simulations, with a particular emphasis on the resonance captures and inclination-growth mechanisms. Most of the systems are found with small inclinations (≤ 10°) at the dispersal of the disc. Even though many systems enter an inclination-type resonance during the migration, the disc usually damps the inclinations on a short timescale. Although the majority of the multiple systems in our simulations are quasi-coplanar, 5% of them end up with high mutual inclinations (≥ 10°). Half of these highly mutually inclined systems result from two- or three-body mean-motion resonance captures, the other half being

  1. From Pixels to Planets

    NASA Technical Reports Server (NTRS)

    Brownston, Lee; Jenkins, Jon M.

    2015-01-01

    The Kepler Mission was launched in 2009 as NASAs first mission capable of finding Earth-size planets in the habitable zone of Sun-like stars. Its telescope consists of a 1.5-m primary mirror and a 0.95-m aperture. The 42 charge-coupled devices in its focal plane are read out every half hour, compressed, and then downlinked monthly. After four years, the second of four reaction wheels failed, ending the original mission. Back on earth, the Science Operations Center developed the Science Pipeline to analyze about 200,000 target stars in Keplers field of view, looking for evidence of periodic dimming suggesting that one or more planets had crossed the face of its host star. The Pipeline comprises several steps, from pixel-level calibration, through noise and artifact removal, to detection of transit-like signals and the construction of a suite of diagnostic tests to guard against false positives. The Kepler Science Pipeline consists of a pipeline infrastructure written in the Java programming language, which marshals data input to and output from MATLAB applications that are executed as external processes. The pipeline modules, which underwent continuous development and refinement even after data started arriving, employ several analytic techniques, many developed for the Kepler Project. Because of the large number of targets, the large amount of data per target and the complexity of the pipeline algorithms, the processing demands are daunting. Some pipeline modules require days to weeks to process all of their targets, even when run on NASA's 128-node Pleiades supercomputer. The software developers are still seeking ways to increase the throughput. To date, the Kepler project has discovered more than 4000 planetary candidates, of which more than 1000 have been independently confirmed or validated to be exoplanets. Funding for this mission is provided by NASAs Science Mission Directorate.

  2. Which Ringed Planet...!?

    NASA Astrophysics Data System (ADS)

    2002-12-01

    Don't worry - you are not the only one who thought this was a nice amateur photo of planet Saturn, Lord of the Rings in our Solar System! But then the relative brightness and positions of the moons may appear somewhat unfamiliar... and the ring system does look unusually bright when compared to the planetary disk...?? Well, it is not Saturn, but Uranus , the next giant planet further out, located at a distance of about 3,000 million km, or 20 times the distance between the Sun and the Earth. The photo shows Uranus surrounded by its rings and some of the moons, as they appear on a near-infrared image that was obtained in the K s -band (at wavelength 2.2 µm) with the ISAAC multi-mode instrument on the 8.2-m VLT ANTU telescope at the ESO Paranal Observatory (Chile) . The exposure was made on November 19, 2002 (03:00 hrs UT) during a planetary research programme. The observing conditions were excellent (seeing 0.5 arcsec) and the exposure lasted 5 min. The angular diameter of Uranus is about 3.5 arcsec. The observers at ISAAC were Emmanuel Lellouch and Thérése Encrenaz of the Observatoire de Paris (France) and Jean-Gabriel Cuby and Andreas Jaunsen (both ESO-Chile). The rings The rings of Uranus were discovered in 1977, from observations during a stellar occultation event by astronomer teams at the Kuiper Airborne Observatory (KAO) and the Perth Observatory (Australia). Just before and after the planet moved in front of the (occulted) star, the surrounding rings caused the starlight to dim for short intervals of time. Photos obtained from the Voyager-2 spacecraft in 1986 showed a multitude of very tenuous rings. These rings are almost undetectable from the Earth in visible light. However, on the present VLT near-infrared picture, the contrast between the rings and the planet is strongly enhanced. At the particular wavelength at which this observation was made, the infalling sunlight is almost completely absorbed by gaseous methane present in the planetary atmosphere

  3. The Chemistry of Planet Formation

    NASA Astrophysics Data System (ADS)

    Oberg, Karin I.

    2017-01-01

    Exo-planets are common, and they span a large range of compositions. The origins of the observed diversity of planetary compositions is largely unconstrained, but must be linked to the planet formation physics and chemistry. Among planets that are Earth-like, a second question is how often such planets form hospitable to life. A fraction of exo-planets are observed to be ‘physically habitable’, i.e. of the right temperature and bulk composition to sustain a water-based prebiotic chemistry, but this does not automatically imply that they are rich in the building blocks of life, in organic molecules of different sizes and kinds, i.e. that they are chemically habitable. In this talk I will argue that characterizing the chemistry of protoplanetary disks, the formation sites of planets, is key to address both the origins of planetary bulk compositions and the likelihood of finding organic matter on planets. The most direct path to constrain the chemistry in disks is to directly observe it. In the age of ALMA it is for the first time possible to image the chemistry of planet formation, to determine locations of disk snowlines, and to map the distributions of different organic molecules. Recent ALMA highlights include constraints on CO snowline locations, the discovery of spectacular chemical ring systems, and first detections of more complex organic molecules. Observations can only provide chemical snapshots, however, and even ALMA is blind to the majority of the chemistry that shapes planet formation. To interpret observations and address the full chemical complexity in disks requires models, both toy models and astrochemical simulations. These models in turn must be informed by laboratory experiments, some of which will be shown in this talk. It is thus only when we combine observational, theoretical and experimental constraints that we can hope to characterize the chemistry of disks, and further, the chemical compositions of nascent planets.

  4. Planet Classification: A Historical Perspective

    NASA Astrophysics Data System (ADS)

    Weintraub, David A.

    2009-05-01

    As philosopher George Santayana famously said, "those who cannot remember the past are condemned to repeat it." The professional astronomy community, as embodied in the IAU, now suffers from Santayana's malady. Ceres was expelled from the community of planets because it apparently was not a planet; yet, no working, scientifically reasonable definition of the word planet existed in the early nineteenth century and so no rational basis existed for excluding or including Ceres or, for that matter, Uranus or the soon-to-be-discovered Neptune from the family of planets. Instead, William Herschel disparaged Ceres as only an "asteroid," a term he invented specifically to separate Ceres and Pallas and Vesta from the true planets. Clearly, in Herschel's view, Ceres was not big enough, and apparently, to Herschel, size mattered. So how big is big enough and by what method was size put in place as the critical scientific metric for assessing planethood? Certainly, as members of the newly discovered asteroid belt, the newly identified asteroids were members of a previously unknown family of objects in the solar system. But why did that make these non-classically known objects asteroids but not planets rather than asteroids and planets? Uranus and Neptune were also members of a newly identified and previously unknown family of solar system objects that we now call "ice giants." On what basis were these two objects embraced as planets and why have these two non-classical objects become known as ice giants and planets rather than ice giants but not planets? Perhaps our scientific predecessors were too quick to render judgment, as they lacked the scientific context in which to understand the many new objects discovered during the years 1781 to 1846. Is that a lesson from the past that we might remember today?

  5. The Effect of Giant Planets on Habitable Planet Formation

    NASA Astrophysics Data System (ADS)

    Quintana, Elisa V.; Barclay, Thomas

    2016-06-01

    The giant planets in the Solar System likely played a large role in shaping the properties of the Earth during its formation. To explore their effects, we numerically model the growth of Earth-like planets around Sun-like stars with and without Jupiter and Saturn analog companions. Employing state-of-the-art dynamical formation models that allow both accretion and collisional fragmentation, we perform hundreds of simulations and quantify the specific impact energies of all collisions that lead to the formation of an Earth-analog. Our model tracks the bulk compositions and water abundances in the cores and mantles of the growing protoplanets to constrain the types of giant planet configurations that allow the formation of habitable planets. We find significant differences in the collisional histories and bulk compositions of the final planets formed in the presence of different giant planet configurations. Exoplanet surveys like Kepler hint at a paucity of Jupiter analogs, thus these analyses have important implications for determining the frequency of habitable planets and also support target selection for future exoplanet characterization missions.

  6. Possible Habitability of Ocean Worlds

    NASA Astrophysics Data System (ADS)

    Noack, Lena; Höning, Dennis; Bredehöft, Jan H.; Lammer, Helmut

    2014-05-01

    In the last decade, the number of detected exoplanets has increased to over thousand confirmed planets and more as yet unconfirmed planet candidates. The scientific community mainly concentrates on terrestrial planets (up to 10 Earth masses) in the habitable zone, which describes the distance from the host star where liquid water can exist at the surface (Kasting et al., 1993). Another target group of interest are ocean worlds, where a terrestrial-like body (i.e. with an iron core and a silicate mantle) is covered by a thick water-ice layer - similar to the icy moons of our solar system but with several Earth masses (e.g. Grasset et al., 2009). When an exoplanet is detected and confirmed as a planet, typically the radius and the mass of it are known, leading to the mean density of the planet that gives hints to possible interior structures. A planet with a large relative iron core and a thick ocean on top of the silicate mantle for example would have the same average planet density as a planet with a more Earth-like appearance (where the main contributor to the mass is the silicate mantle). In this study we investigate how the radius and mass of a planet depend on the amount of water, silicates and iron present (after Wagner et al., 2011) the occurence of high-pressure-ice in the water-ice layer (note: we only consider surface temperatures at which liquid water exists at the surface) if the ocean layer influences the initiation of plate tectonics We assume that ocean worlds with a liquid ocean layer (and without the occurence of high-pressure ice anywhere in the water layer) and plate tectonics (especially the occurence of subduction zones, hydrothermal vents and continental formation) may be called habitable (Class III/IV habitats after Lammer et al., 2009). References: Kasting, J.F., Whitmire, D.P., and Reynolds, R.T. (1993). Habitable Zones around Main Sequence Stars. Icarus 101, 108-128. Grasset, O., Schneider, J., and Sotin, C. (2009). A study of the accuracy

  7. An Update on Planet Nine

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2016-07-01

    Whats the news coming from the research world on the search for Planet Nine? Read on for an update from a few of the latest studies.Artists illustration of Planet Nine, a hypothesized Neptune-sized planet orbiting in the distant reaches of our solar system. [Caltech/Robert Hurt]What is Planet Nine?In January of this year, Caltech researchers Konstantin Batygin and Mike Brown presented evidence of a distant ninth planet in our solar system. They predicted this planet to be of a mass and volume consistent with a super-Earth, orbiting on a highly eccentric pathwith a period of tens of thousands of years.Since Batygin and Browns prediction, scientists have been hunting for further signs of Planet Nine. Though we havent yet discovered an object matching its description, we have come up with new strategies for finding it, we set some constraints on where it might be, and we made some interesting theoretical predictions about its properties.Visualizations of the resonant orbits of the four longest-period Kuiper belt objects, depicted in a frame rotating with the mean angular velocity of Planet Nine. Planet Nines position is on the right (with the trace of possible eccentric orbits e=0.17 and e=0.4 indicated in red). [Malhotra et al 2016]Here are some of the newest constraints on Planet Nine from studies published just within the past two weeks.Resonant OrbitsRenu Malhotra (University of Arizonas Lunar and Planetary Laboratory) and collaborators present further evidence of the shaping of solar system orbits by the hypothetical Planet Nine. The authors point out that the four longest-period Kuiper belt objects (KBOs) have orbital periods close to integer ratios with each other. Could it be that these outer KBOs have become locked into resonant orbits with a distant, massive body?The authors find that a distant planet orbiting with a period of ~17,117 years and a semimajor axis ~665 AU would have N/1 and N/2 period ratios with these four objects. If this is correct, it

  8. THE FIRST PLANETS: THE CRITICAL METALLICITY FOR PLANET FORMATION

    SciTech Connect

    Johnson, Jarrett L.; Li Hui

    2012-06-01

    A rapidly growing body of observational results suggests that planet formation takes place preferentially at high metallicity. In the core accretion model of planet formation this is expected because heavy elements are needed to form the dust grains which settle into the midplane of the protoplanetary disk and coagulate to form the planetesimals from which planetary cores are assembled. As well, there is observational evidence that the lifetimes of circumstellar disks are shorter at lower metallicities, likely due to greater susceptibility to photoevaporation. Here we estimate the minimum metallicity for planet formation, by comparing the timescale for dust grain growth and settling to that for disk photoevaporation. For a wide range of circumstellar disk models and dust grain properties, we find that the critical metallicity above which planets can form is a function of the distance r at which the planet orbits its host star. With the iron abundance relative to that of the Sun [Fe/H] as a proxy for the metallicity, we estimate a lower limit for the critical abundance for planet formation of [Fe/H]{sub crit} {approx_equal} -1.5 + log (r/1 AU), where an astronomical unit (AU) is the distance between the Earth and the Sun. This prediction is in agreement with the available observational data, and carries implications for the properties of the first planets and for the emergence of life in the early universe. In particular, it implies that the first Earth-like planets likely formed from circumstellar disks with metallicities Z {approx}> 0.1 Z{sub Sun }. If planets are found to orbit stars with metallicities below the critical metallicity, this may be a strong challenge to the core accretion model.

  9. PLANET TOPERS: Planets, Tracing the Transfer, Origin, Preservation, and Evolution of their ReservoirS

    NASA Astrophysics Data System (ADS)

    Dehant, Veronique; Breuer, Doris; Claeys, Philippe; Debaille, Vinciane; De Keyser, Johan; Javaux, Emmanuelle; Goderis, Steven; Karatekin, Ozgur; Mattielli, Nadine; Noack, Lena; Spohn, Tilman; Carine Vandaele, Ann; Vanhaecke, Frank; Van Hoolst, Tim; Wilquet, Valerie

    2013-04-01

    , the possibility to have liquid water, the thermal state, the energy budget and the availability of nutrients. Shortly after formation (Hadean 4.4-4.0 Ga (billion years)), evidence supports the presence of a liquid ocean and continental crust on Earth (Wilde et al., 2001, Nature, 409, 175-178), Earth may thus have been habitable very early on. The origin of life is not understood yet but the oldest putative traces of life occur in the early Archaean (~3.5 Ga). Studies of early Earth habitats documented in rock containing traces of fossil life provide information about environmental conditions suitable for life beyond Earth, as well as methodologies for their identification and analyses. The extreme values of environmental conditions in which life thrives today can also be used to characterize the "envelope" of the existence of life and the range of potential extraterrestrial habitats. The requirement of nutrients for biosynthesis, growth, and reproduction suggest that a tectonically active planet, with liquid water is required to replenish nutrients and sustain life (as currently known). These dynamic processes play a key role in the apparition and persistence of life. This contribution will focus on the highlights of the work of the IAP Planet TOPERS.

  10. Habitable Planets: Interior Dynamics and Long-Term Evolution

    NASA Astrophysics Data System (ADS)

    Tackley, Paul J.; Ammann, Michael M.; Brodholt, John P.; Dobson, David P.; Valencia, Diana

    2014-04-01

    Here, the state of our knowledge regarding the interior dynamics and evolution of habitable terrestrial planets including Earth and super-Earths is reviewed, and illustrated using state-of-the-art numerical models. Convection of the rocky mantle is the key process that drives the evolution of the interior: it causes plate tectonics, controls heat loss from the metallic core (which generates the magnetic field) and drives long-term volatile cycling between the atmosphere/ocean and interior. Geoscientists have been studying the dynamics and evolution of Earth's interior since the discovery of plate tectonics in the late 1960s and on many topics our understanding is very good, yet many first-order questions remain. It is commonly thought that plate tectonics is necessary for planetary habitability because of its role in long-term volatile cycles that regulate the surface environment. Plate tectonics is the surface manifestation of convection in the 2900-km deep rocky mantle, yet exactly how plate tectonics arises is still quite uncertain; other terrestrial planets like Venus and Mars instead have a stagnant lithosphere- essentially a single plate covering the entire planet. Nevertheless, simple scalings as well as more complex models indicate that plate tectonics should be easier on larger planets (super-Earths), other things being equal. The dynamics of terrestrial planets, both their surface tectonics and deep mantle dynamics, change over billions of years as a planet cools. Partial melting is a key process influencing solid planet evolution. Due to the very high pressure inside super-Earths' mantles the viscosity would normally be expected to be very high, as is also indicated by our density function theory (DFT) calculations. Feedback between internal heating, temperature and viscosity leads to a superadiabatic temperature profile and self-regulation of the mantle viscosity such that sluggish convection still occurs.

  11. Teaching Personality Theories Using Popular Music

    ERIC Educational Resources Information Center

    Leck, Kira

    2006-01-01

    Previously, psychology instructors have used popular music to illustrate psychological concepts in the classroom. In this study, students enrolled in a personality theories class heard 13 popular songs that demonstrated various concepts. Students then selected and analyzed their own songs that contained elements of personality theories. Test…

  12. Using Popular Culture to Teach Quantitative Reasoning

    ERIC Educational Resources Information Center

    Hillyard, Cinnamon

    2007-01-01

    Popular culture provides many opportunities to develop quantitative reasoning. This article describes a junior-level, interdisciplinary, quantitative reasoning course that uses examples from movies, cartoons, television, magazine advertisements, and children's literature. Some benefits from and cautions to using popular culture to teach…

  13. Anthropology and Popular Culture: A Case Study.

    ERIC Educational Resources Information Center

    Estes, Jack

    The study of popular culture in the United States is an appropriate anthropological endeavor, as evidenced in a case study of the volcanic eruption of Mt. St. Helens in Oregon. By examining its popular arts, anthropologists gain understanding of the culture and its people. For example, an analysis of reactions to the Mt. St. Helens eruption…

  14. Living-History Villages as Popular Entertainers.

    ERIC Educational Resources Information Center

    Geist, Christopher D.

    1994-01-01

    Discusses the furor created when Walt Disney Studios announced plans to develop a "historic amusement park" near the Manassas (Virginia) National Battlefield Park. Maintains that the public debate over the popular understanding of history reflects an ongoing tension between academic historians and the purveyors of popular history. (CFR)

  15. Using Popular Music to Teach Global Education.

    ERIC Educational Resources Information Center

    Rogers, Jim

    1990-01-01

    Shows how studying sources of popular music and instruments help students understand historical patterns of immigration and geography. Presents lessons and materials for exploring origins of popular musical instruments and music that developed in the United States from other cultures. Includes several related classroom activities, recommended…

  16. Popular Media and the Teaching of English.

    ERIC Educational Resources Information Center

    Giblin, Thomas R., Ed.

    This work is a collection of ideas on the why and the how of popular media study in the secondary English classroom. Chapters are divided into eight sections: "Developing a Rationale for Popular Media Study,""An English Teacher's Challange,""Understanding McLuhan,""An Expanding View of…

  17. Popular Documentation and Communication Centres in Brazil.

    ERIC Educational Resources Information Center

    Cardoso, Ana Maria P.

    1993-01-01

    Presents a study of the popular documentation and communication centers in Brazil which have developed to preserve the history of the struggles of the lower classes and to act as popular information services that fill information needs not met by traditional libraries. Social, economic, and political issues in Brazil are outlined. (Contains 10…

  18. Spanish Federation of Popular Universities (FEUP)

    ERIC Educational Resources Information Center

    Serrano, Isabel Garcia-Longoria

    2006-01-01

    This article features the Spanish Popular Universities, which are defined as "a project of cultural development that acts in the municipality, whose objective is to promote social participation, education, training, and culture in order to improve life quality" (Federation of Popular Education Universities, 2000). A century of history of…

  19. Substance Use in Popular Movies and Music.

    ERIC Educational Resources Information Center

    Roberts, Donald F.; Henriksen, Lisa; Christenson, Peter G.

    This study examines the frequency and nature of substance use in the most popular movie rentals and songs of 1996 and 1997. The intent was to determine the accuracy of public perceptions about extensive substance use in media popular among youth. Because teenagers are major consumers of movies and music, there is concern about the potential for…

  20. Women in Popular Culture: A Reference Guide.

    ERIC Educational Resources Information Center

    Fishburn, Katherine

    This book explores how women have been portrayed in various forms of American popular culture over the years. In an introductory section, it is suggested that popular culture has generally used women to represent a social mythology that is built around women's subordinate status, a position that current feminists reject. Chapter 1 reviews books…

  1. Educational And Public Outreach Software On Planet Detection For The Macintosh (TM)

    NASA Technical Reports Server (NTRS)

    Koch, David; Brady, Victoria; Cannara, Rachel; Witteborn, Fred C. (Technical Monitor)

    1996-01-01

    The possibility of extra-solar planets has been a very popular topic with the general public for years. Considerable media coverage of recent detections has only heightened the interest in the topic. School children are particularly interested in learning about space. Astronomers have the knowledge and responsibility to present this information in both an understandable and interesting format. Since most classrooms and homes are now equipped with computers this media can be utilized to provide more than a traditional "flat" presentation. An interactive "stack" has been developed using Hyperstudio (TM). The major topics include: "1996 - The Break Through Year In Planet Detection"; "What Determines If A Planet Is Habitable?"; "How Can We Find Other Planets (Search Methods)"; "All About the Kepler Mission: How To Find Earth-Sized Planets"; and "A Mission Simulator". Using the simulator, the student records simulated observations and then analyzes and interprets the data within the program stacks to determine the orbit and planet size, the planet's temperature and surface gravity, and finally determines if the planet is habitable. Additional related sections are also included. Many of the figures are animated to assist in comprehension of the material. A set of a dozen lesson plans for the middle school has also been drafted.

  2. The planet and the painted globe

    SciTech Connect

    Rockwell, R.C.

    1994-12-31

    Some years ago a clever cartoonist drew a puzzled astronaut looking down on an Earth painted like a library globe: blocks of pinks, greens, and blues set off the countries, bold lines clearly delineated boundaries, and countries were identified in large letters. Research on human dimensions of global environmental changes would be so much easier if that cartographer`s globe were real. Unfortunately, what the astronauts have actually seen is a planet from which human politics have seemingly disappeared. They see an Earth on which the human creations of countries and their boundaries are veiled by the natural features of the planet-the oceans, seas, rivers, forests, ice fields, plain, and mountains that were mostly here before anyone thought to draw a national boundary or paint a map. This globe without apparent political demarcations is the natural stage on which environmental changes play. It is not, however, the globe on which social science research is conducted. The human-centered globe of the social sciences has places, cities, and nation-states of which social scientists must take account. How to do so in a manner that permits linkages of social and natural science research is problematic. This article discusses the interactions between these two different types of research in looking at global climate change.

  3. The occurrence of Jovian planets and the habitability of planetary systems

    PubMed Central

    Lunine, Jonathan I.

    2001-01-01

    Planets of mass comparable to or larger than Jupiter's have been detected around over 50 stars, and for one such object a definitive test of its nature as a gas giant has been accomplished with data from an observed planetary transit. By virtue of their strong gravitational pull, giant planets define the dynamical and collisional environment within which terrestrial planets form. In our solar system, the position and timing of the formation of Jupiter determined the amount and source of the volatiles from which Earth's oceans and the source elements for life were derived. This paper reviews and brings together diverse observational and modeling results to infer the frequency and distribution of giant planets around solar-type stars and to assess implications for the habitability of terrestrial planets. PMID:11158551

  4. The occurrence of Jovian planets and the habitability of planetary systems.

    PubMed

    Lunine, J

    2001-01-30

    Planets of mass comparable to or larger than Jupiter's have been detected around over 50 stars, and for one such object a definitive test of its nature as a gas giant has been accomplished with data from an observed planetary transit. By virtue of their strong gravitational pull, giant planets define the dynamical and collisional environment within which terrestrial planets form. In our solar system, the position and timing of the formation of Jupiter determined the amount and source of the volatiles from which Earth's oceans and the source elements for life were derived. This paper reviews and brings together diverse observational and modeling results to infer the frequency and distribution of giant planets around solar-type stars and to assess implications for the habitability of terrestrial planets.

  5. Astrobiology And Extrasolar Planets- A New Lecture Course At Potsdam University

    NASA Astrophysics Data System (ADS)

    Franck, S. A.; von Bloh, W.; Bounama, Ch.

    2006-08-01

    Astrobiology studies the origin, evolution, distribution, and future of life on Earth and in the Universe. This addresses a very wide range of questions that have been asked by mankind from the beginning. On the other hand, the discovery of the first extrasolar planet orbiting a Sun-like star by Mayor and Queloz in 1995 opened a new area for astrobiological research. Although most of the newly discovered extrasolar planets are giants with no underlying solid surfaces or oceans that could support a biosphere, the distribution of masses lets scientists suppose that there must be a multitude of planets with lower masses, including Earth-mass planets. The lecture course contains the following topics: Survey about Extrasolar Planets, Detection Methods, Simple Earth System Models, Dynamical Earth System Models, Habitable Zones, Dynamical Habitability, Rare Earth Hypothesis, Drake Formula, Panspermia, Origin of Life, Cambrian Explosion, Impacts and Climate, Long-Term Future Scenarios, Future Space Missions.

  6. Planet Hunters: A Status Report

    NASA Astrophysics Data System (ADS)

    Schwamb, Megan E.; Orosz, J. A.; Carter, J. A.; Fischer, D. A.; Howard, A. W.; Crepp, J. R.; Welsh, W. F.; Kaib, N. A.; Lintott, C. J.; Terrell, D.; Jek, K. J.; Gagliano, R.; Parrish, M.; Smith, A. M.; Lynn, S.; Brewer, J. M.; Giguere, M. J.; Schawinski, K.; Simpson, R. J.

    2012-10-01

    The Planet Hunters (http://www.planethunters.org) citizen science project uses the power of human pattern recognition via the World Wide Web to identify transits in the Kepler public data. Planet Hunters uses the Zooniverse (http://www.zooniverse.org) platform to present visitors to the Planet Hunters website with a randomly selected 30-day light curve segment from one of Kepler's 160,000 target stars. Volunteers are asked to draw boxes to mark the locations of visible transits with multiple independent classifiers reviewing each 30-day light curve segment. Since December 2010, more than 170,000 members of the general public have participated in Planet Hunters contributing over 12.5 million classifications searching the 1 1/2 years of publicly released Kepler observations. Planet Hunters is a novel and complementary technique to the automated transit detection algorithms, providing an independent assessment of the completeness of the Kepler exoplanet inventory. We report the latest results from Planet Hunters, highlighting in particular our latest efforts to search for circumbinary planets (planets orbiting a binary star) and single transit events in the first 1.5 years of public Kepler data. We will present a status report of our search of the first 6 Quarters of Kepler data, introducing our new planet candidates and sharing the results of our observational follow-up campaign to characterize these planetary systems. Acknowledgements: MES is supported by a NSF Astronomy and Astrophysics Postdoctoral Fellowship under award AST-1003258. This is research is supported in part by an American Philosophical Society Franklin Grant.

  7. Terrestrial planets in high-mass disks without gas giants

    NASA Astrophysics Data System (ADS)

    de Elía, G. C.; Guilera, O. M.; Brunini, A.

    2013-09-01

    Context. Observational and theoretical studies suggest that planetary systems consisting only of rocky planets are probably the most common in the Universe. Aims: We study the potential habitability of planets formed in high-mass disks without gas giants around solar-type stars. These systems are interesting because they are likely to harbor super-Earths or Neptune-mass planets on wide orbits, which one should be able to detect with the microlensing technique. Methods: First, a semi-analytical model was used to define the mass of the protoplanetary disks that produce Earth-like planets, super-Earths, or mini-Neptunes, but not gas giants. Using mean values for the parameters that describe a disk and its evolution, we infer that disks with masses lower than 0.15 M⊙ are unable to form gas giants. Then, that semi-analytical model was used to describe the evolution of embryos and planetesimals during the gaseous phase for a given disk. Thus, initial conditions were obtained to perform N-body simulations of planetary accretion. We studied disks of 0.1, 0.125, and 0.15 M⊙. Results: All our simulations form massive planets on wide orbits. For a 0.1 M⊙ disk, 2-3 super-Earths of 2.8 to 5.9 M⊕ are formed between 2 and 5 AU. For disks of 0.125 and 0.15 M⊙, our simulations produce a 10-17.1 M⊕ planet between 1.6 and 2.7 AU, and other super-Earths are formed in outer regions. Moreover, six planets survive in the habitable zone (HZ). These planets have masses from 1.9 to 4.7 M⊕ and significant water contents ranging from 560 to 7482 Earth oceans, where one Earth ocean represents the amount of water on Earth's surface, which equals 2.8 × 10-4M⊕. Of the six planets formed in the HZ, three are water worlds with 39%-44% water by mass. These planets start the simulations beyond the snow line, which explains their high water abundances. In general terms, the smaller the mass of the planets observed on wide orbits, the higher the possibility to find water worlds in the

  8. Planet-Planet Scattering and White Dwarf Pollution

    NASA Astrophysics Data System (ADS)

    Joasil, Arielle; Payne, Matthew John; Veras, Dimitri

    2017-01-01

    About one-quarter to one-half of white dwarfs are observed to have polluted atmospheres. White dwarfs (WD) are expected to be chemically stratified, with heavy elements rapidly sinking. The frequent observation of heavy element pollution in WD atmospheres indicates that there must be a copious and frequent supply of rocky material from remnant planetary systems acting as a pollutant. Recently, the white dwarf WD 1145+017 has been observed to have been transited by a rocky body apparently in the process of disintegrating (Vanderburg et al. 2015).Post-main sequence expansion may render the planetary system unstable (Veras 2016). Planets orbiting the white dwarf may perturb and scatter one another. If this scattering happens, any moons can be scattered about the system. As such, one possible source of the material polluting WDs is destabilized exomoons (Payne et al. 2016a, 2016b). Moons offer a plausible source of pollution due to their large total mass (in the Solar system), and their generally rocky composition that matches that found in the atmospheric pollution of WDs. During a planet-planet scattering event, the probability that a moon will be ejected from its parent planet is a function of the velocity of the perturbing planet and the distance between the perturbed moon and the perturbing planet (as well as the initial orbit of the moon). We review the results of Payne et al. (2016a, 2016b) and present new results illustrating the probability of moon ejection as a function of these key parameters. We demonstrate the utility of these results for (a) the pollution and WDs, and for (b) general planet-planet scattering scenarios around main-sequence stars.

  9. Comparative ionospheres. I - The inner planets. II - The outer planets

    NASA Technical Reports Server (NTRS)

    Cravens, T. E.

    1983-01-01

    A description is given first of the fundamental physical and chemical processes controlling the thermospheres and ionospheres of the inner planets, Venus and Mars. A comparison is made between the neutral composition and temperature structure of Venus and Mars and those of the earth. Consideration is then given to the chemical and diffusion processes in the ionosphere. After a brief treatment of the ionospheric energetics and heat sources, the mechanisms underlying the maintenance of the nightside ionosphere of Venus are reviewed. A description is then given of the upper atmospheres and ionospheres of the major planets, Jupiter and Saturn. The treatment of the temperature structure and composition of the thermospheres of the major planets includes a description of the physical and chemical processes controlling the hydrocarbons and atomic hydrogen. A comparison is then made between the ionospheres of the major planets and those of the inner planets. It is noted that Io and Titan also have atmospheres and ionospheres, and these are treated briefly. Even though comets cannot be classed as planets, they have atmospheres and ionospheres that are not gravitationally confined.

  10. Habitable planet finder

    NASA Astrophysics Data System (ADS)

    Ditto, Thomas D.

    2012-09-01

    A notional space telescope configuration is presented that addresses issues of angular resolution, spectral bandwidth and rejection of host star glare by means of a double dispersion architecture. The telescope resolves angle by wavelength. In an earlier embodiment for surveys, a primary objective grating telescope architecture was shown to acquire millions of objects in one observation cycle, one wave length at a time. The proposed HPF can detect exquisite spectral signatures out of millions of wavelengths in albedos - one exoplanetary system at a time. Like its predecessor, the new HPF telescope has a ribbon-shaped flat gossamer membrane primary objective that lends itself to space deployment, but the preferred embodiment uses a holographic optical element rather than a plane grating. The HOE provides an improvement in efficiency at select wavelength bands. The considerable length of the membrane can be in the 100 meter class providing angular resolution sufficient to resolve planets in the habitable zone and also spectral resolution sufficient to earmark habitability. A novel interferometric secondary spectrograph rejects host star glare. However, the architecture cannot disambiguate multiple stellar sources and may require unprecedented focal lengths in the primary objective to isolate one system at a time.

  11. PLANETS ON THE EDGE

    SciTech Connect

    Valsecchi, Francesca; Rasio, Frederic A.

    2014-05-20

    Hot Jupiters formed through circularization of high-eccentricity orbits should be found at orbital separations a exceeding twice that of their Roche limit a {sub R}. Nevertheless, about a dozen giant planets have now been found well within this limit (a {sub R} < a < 2 a {sub R}), with one coming as close as 1.2 a {sub R}. In this Letter, we show that orbital decay (starting beyond 2 a {sub R}) driven by tidal dissipation in the star can naturally explain these objects. For a few systems (WASP-4 and 19), this explanation requires the linear reduction in convective tidal dissipation proposed originally by Zahn and verified by recent numerical simulations, but rules out the quadratic prescription proposed by Goldreich and Nicholson. Additionally, we find that WASP-19-like systems could potentially provide direct empirical constraints on tidal dissipation, as we could soon be able to measure their orbital decay through high precision transit timing measurements.

  12. Extrasolar planet imaging

    NASA Astrophysics Data System (ADS)

    Labeyrie, Antoine; Le Coroller, Herve

    2004-10-01

    The coronagraphic techniques serving to reject most light from a star, when trying to image a nearby planet, can be pushed with an adaptive holographic element. Located after the coronagraph, it can in principle remove most of the residual star light by adding a phase-shifted holographic reconstruction of it . The scheme is also usable within each sub-aperture of a diluted hypertelescope array, sufficiently large to resolve details of an exo-Earth. A possible panoramic version of the previously mentioned Exo-Earth Imager is shaped as a virtual bubble of 400 km diameter , consisting of thousands of 3-meter mirrors, free-flying and arranged co-spherically. The half-size focal sphere is explored by beam combiners, one for each exo-Earth observed within tens of parsecs. Each beam-combiner includes a kilometer-sized corrector of spherical aberration at F/2, which is also diluted and consisting of small free-flyers. The instrument is expected to provide direct coronagraphic images of exo-Earths, resolved in 50×50 resels, with enough dynamic range obtained in 30mn exposures to search colored features and their seasonal variations, indicative of photosynthetic life .

  13. Then Why Do They Call Earth the Blue Planet?

    NASA Technical Reports Server (NTRS)

    2005-01-01

    While the most common photographs of Earth taken from space show the planet covered in blue water, NASA has managed to produce detailed color images, using satellite imagery, that show the remarkable variation of colors that actually make up the oceanic surface. An ocean s color is determined by the interaction of surface waters with sunlight, and surface waters can contain any number of different particles and dissolved substances, which could then change the color. Then Why Do They Call Earth the Blue Planet? The particles are mostly phytoplankton, the microscopic, single-celled ocean plants that are the primary food source for much marine life. Remote detection of phytoplankton provides information about the uptake and cycling of carbon by the ocean through photosynthesis, as well as the overall health of the water. Inorganic particles and substances dissolved in the water also affect its color, particularly in coastal regions. Satellite images can be used to calculate the concentrations of these materials in surface waters, as well as the levels of biological activity. The satellites allow a global view that is not available from ship or shore. NASA s orbiting satellites offer a unique vantage point for studying the oceans. By resolving the biological, chemical, and physical conditions in surface waters, they have allowed the oceanographic community to make huge leaps in its understanding of oceanographic processes on regional and global fronts. The study of ocean color, in particular, has been integral in helping researchers understand the natural and human-induced changes in the global environment and establishing the role of the oceans in the biochemical cycles of elements that influence the climate and the distribution of life on Earth.

  14. No Pseudosynchronous Rotation for Terrestrial Planets and Moons

    NASA Astrophysics Data System (ADS)

    Makarov, Valeri V.; Efroimsky, Michael

    2013-02-01

    We re-examine the popular belief that a telluric planet or a satellite on an eccentric orbit can, outside a spin-orbit resonance, be captured in a quasi-static tidal equilibrium called pseudosynchronous rotation. The existence of such configurations was deduced from oversimplified tidal models assuming either a constant tidal torque or a torque linear in the tidal frequency. A more accurate treatment requires that the torque be decomposed into the Darwin-Kaula series over the tidal modes, and that this decomposition be combined with a realistic choice of rheological properties of the mantle, which we choose to be a combination of the Andrade model at ordinary frequencies and the Maxwell model at low frequencies. This development demonstrates that there exist no stable equilibrium states for solid planets and moons, other than spin-orbit resonances.

  15. NO PSEUDOSYNCHRONOUS ROTATION FOR TERRESTRIAL PLANETS AND MOONS

    SciTech Connect

    Makarov, Valeri V.; Efroimsky, Michael E-mail: michael.efroimsky@usno.navy.mil

    2013-02-10

    We re-examine the popular belief that a telluric planet or a satellite on an eccentric orbit can, outside a spin-orbit resonance, be captured in a quasi-static tidal equilibrium called pseudosynchronous rotation. The existence of such configurations was deduced from oversimplified tidal models assuming either a constant tidal torque or a torque linear in the tidal frequency. A more accurate treatment requires that the torque be decomposed into the Darwin-Kaula series over the tidal modes, and that this decomposition be combined with a realistic choice of rheological properties of the mantle, which we choose to be a combination of the Andrade model at ordinary frequencies and the Maxwell model at low frequencies. This development demonstrates that there exist no stable equilibrium states for solid planets and moons, other than spin-orbit resonances.

  16. PLANET TOPERS: Planets, Tracing the Transfer, Origin, Preservation, and Evolution of their ReservoirS

    NASA Astrophysics Data System (ADS)

    Dehant, Véronique; Breuer, Doris; Claeys, Philippe; Debaille, Vinciane; de Keyser, Johan; Javaux, Emmanuelle; Goderis, Steven; Karatekin, Ozgur; Matielli, Nadine; Noack, Lena; Spohn, Tilman; Carine Vandaele, Ann; Vanhaecke, Frank; van Hoolst, Tim; Wilquet, Valérie; The PLANET Topers Team

    2015-04-01

    , meteorite impacts, and erosion, modify the planetary surface, the possibility to have liquid water, the thermal state, the energy budget and the availability of nutrients. Shortly after formation (Hadean 4.4-4.0 Ga), evidence supports the presence of a liquid ocean and continental crust on Earth (Wilde et al., 2001), Earth may thus have been habitable very early on (Strasdeit, 2010). The origin of life is not understood yet but the oldest putative traces of life occur in the early Archaean (~3.5 Ga). The extreme values of environmental conditions in which life thrives today can also be used to characterize the "envelope" of the existence of life and the range of potential extraterrestrial habitats. The requirement of nutrients for biosynthesis, growth, and reproduction suggests that a tectonically active planet, with liquid water is required to replenish nutrients and sustain life (as currently known). These dynamic processes play a key role in the apparition and persistence of life. Mars is presently on the edge of the HZ, but may have been much more hospitable early in its history, as the examination of its surface suggests the existence of water very early on (about 4 Ga ago) (Bibring et al., 2005; 2006). Since then, Mars lost most of its atmosphere, preventing the presence of liquid water at the surface. In comparison Earth is habitable at present and has been for at least 3.5 Ga.

  17. Voyager to the Seventh Planet.

    ERIC Educational Resources Information Center

    Gold, Michael

    1986-01-01

    Presents recent findings obtained by the Voyager 2 mission on Uranus. Updates information on the planet's moons, rings, atmosphere, and magnetic field. Illustrations and diagrams of selected aspects of Uranus are included. (ML)

  18. Thermoelectric Outer Planets Spacecraft (TOPS)

    NASA Technical Reports Server (NTRS)

    1973-01-01

    The research and advanced development work is reported on a ballistic-mode, outer planet spacecraft using radioisotope thermoelectric generator (RTG) power. The Thermoelectric Outer Planet Spacecraft (TOPS) project was established to provide the advanced systems technology that would allow the realistic estimates of performance, cost, reliability, and scheduling that are required for an actual flight mission. A system design of the complete RTG-powered outer planet spacecraft was made; major technical innovations of certain hardware elements were designed, developed, and tested; and reliability and quality assurance concepts were developed for long-life requirements. At the conclusion of its active phase, the TOPS Project reached its principal objectives: a development and experience base was established for project definition, and for estimating cost, performance, and reliability; an understanding of system and subsystem capabilities for successful outer planets missions was achieved. The system design answered long-life requirements with massive redundancy, controlled by on-board analysis of spacecraft performance data.

  19. Revitalizing Ernst Mach's Popular Scientific Lectures

    NASA Astrophysics Data System (ADS)

    Euler, Manfred

    2007-06-01

    Compared to Ernst Mach's influence on the conceptual development of physics, his efforts to popularize science and his reflections on science literacy are known to a much lesser degree. The approach and the impact of Mach's popular scientific lectures are discussed in view of today's problems of understanding science. The key issues of Mach's popular scientific lectures, reconsidered in the light of contemporary science, still hold a high potential in fascinating a general audience. Moreover, Mach's grand theme, the relation of the physical to the psychical, is suited to contribute to a dialogue between different knowledge cultures, e.g. science and humanities.

  20. Inside-Out Planet Formation

    NASA Astrophysics Data System (ADS)

    Tan, Jonathan

    The objective of this proposal is to investigate several aspects of the Inside-Out Planet Formation model, recently proposed by Chatterjee & Tan (2014). This model involves sequential formation of planets from pebble (i.e., ~centimeter to ~meter-sized particle)-rich rings in the inner regions of protoplanetary disks. Pebbles, formed from dust coagulation, migrate to the inner disk because of gas drag and collect at a local pressure maximum associated with the inner boundary of the dead zone with a magneto-rotational instability (MRI)-active region. Once the first planet forms from the pebble ring, it may either grow to open a gap leading to dead zone retreat or migrate inwards into the MRI-active region. In either case, a new pebble ring starts to form exterior to the planet, and the process repeats. This model may help explain the systems of tightly packed inner planets (STIPs) recently discovered by Kepler. We propose to: (1) Calculate the radial structure of the inner accretion disk to estimate locations of the dead zone inner boundary (DZIB), most likely set by thermal ionization of alkali metals; (2) Construct a model of pebble formation and radial drift to estimate pebble supply rates to the inner disk, including analysis of MHD simulations of the MRI to assess the effect of pressure fluctuations due to turbulence; (3) Simulate the interactions of protoplanets that are expected to form via gravitational instability from the pebble ring to examine if a single dominant planet can form by collisions and/or continued pebble accretion, and the timescale for this process; (4) Simulate planet-disk interactions near the DZIB using the FARGO code to study gap-opening and migration of planets; (5) Study planetary system synthesis via Inside-Out Planet Formation via a series of connected FARGO simulations; (6) Compare model results, such as planet masses and orbital properties, with observed exoplanet systems. This work has the potential to help provide a theoretical

  1. Planet Hunters: Kepler by Eye

    NASA Astrophysics Data System (ADS)

    Schwamb, Megan E.; Lintott, C.; Fischer, D.; Smith, A. M.; Boyajian, T. S.; Brewer, J. M.; Giguere, M. J.; Lynn, S.; Parrish, M.; Schawinski, K.; Schmitt, J.; Simpson, R.; Wang, J.

    2014-01-01

    Planet Hunters (http://www.planethunters.org), part of the Zooniverse's (http://www.zooniverse.org) collection of online citizen science projects, uses the World Wide Web to enlist the general public to identify transits in the pubic Kepler light curves. Planet Hunters utilizes human pattern recognition to identify planet transits that may be missed by automated detection algorithms looking for periodic events. Referred to as ‘crowdsourcing’ or ‘citizen science’, the combined assessment of many non-expert human classifiers with minimal training can often equal or best that of a trained expert and in many cases outperform the best machine-learning algorithm. Visitors to the Planet Hunters' website are presented with a randomly selected ~30-day light curve segment from one of Kepler’s ~160,000 target stars and are asked to draw boxes to mark the locations of visible transits in the web interface. 5-10 classifiers review each 30-day light curve segment. Since December 2010, more than 260,000 volunteers world wide have participated, contributing over 20 million classifications. We have demonstrated the success of a citizen science approach with the project’s more than 20 planet candidates, the discovery of PH1b, a transiting circumbinary planet in a quadruple star system, and the discovery of PH2-b, a confirmed Jupiter-sized planet in the habitable zone of a Sun-like star. I will provide an overview of Planet Hunters, highlighting several of project's most recent exoplanet and astrophysical discoveries. Acknowledgements: MES was supported in part by a NSF AAPF under award AST-1003258 and a American Philosophical Society Franklin Grant. We acknowledge support from NASA ADAP12-0172 grant to PI Fischer.

  2. Polarisation of Planets and Exoplanets

    NASA Astrophysics Data System (ADS)

    Bailey, Jeremy; Kedziora-Chudczer, Lucyna; Bott, Kimberly; Cotton, Daniel V.

    2015-11-01

    We present observations of the linear polarisation of several hot Jupiter systems with our new high-precision polarimeter HIPPI (HIgh Precision Polarimetric Instrument). By looking at the combined light of the star and planet we aim to detect the polarised light reflected from the planet's atmosphere. This can provide information on the presence of, and nature of clouds in the atmosphere, and constrain the geometric albedo of the planet. The method is applicable to both transitting and non-transitting planets, and can also be used to determine the inclination of the system, and thus the true mass for radial velocity detected planets.To predict and interpret the polarisation from such observations, we have also developed an advanced polarimetric modelling capability, by incoroporating full polarised radiative transfer into our atmospheric modelling code VSTAR. This is done using the VLIDORT vector radiative transfer solver (Spurr, 2006). The resulting code allows us to predict disc-resolved, phase-resolved, and spectrally-resolved intensity and linear polarisation for any planet, exoplanet, brown dwarf or cool star atmosphere that can be modelled with VSTAR. We have tested the code by reproducing benchmark calculations in polarised radiative transfer, and by Solar System test cases, including reproducing the classic Hansen and Hovenier (1974) calculation of the polarisation phase curves of Venus.Hansen, J.E., & Hovenier, J.W., 1974, J. Atmos. Sci., 31, 1137Spurr, R., 2006, JQSRT, 102, 316.

  3. Atmospheres of the Giant Planets

    NASA Technical Reports Server (NTRS)

    Ingersoll, Andrew P.

    2002-01-01

    The giant planets, Jupiter, Saturn, Uranus, and Neptune, are fluid objects. They have no solid surfaces because the light elements constituting them do not condense at solar-system temperatures. Instead, their deep atmospheres grade downward until the distinction between gas and liquid becomes meaningless. The preceding chapter delved into the hot, dark interiors of the Jovian planets. This one focuses on their atmospheres, especially the observable layers from the base of the clouds to the edge of space. These veneers arc only a few hundred kilometers thick, less than one percent of each planet's radius, but they exhibit an incredible variety of dynamic phenomena. The mixtures of elements in these outer layers resemble a cooled-down piece of the Sun. Clouds precipitate out of this gaseous soup in a variety of colors. The cloud patterns are organized by winds, which are powered by heat derived from sunlight (as on Earth) and by internal heat left over from planetary formation. Thus the atmospheres of the Jovian planets are distinctly different both compositionally and dynamically from those of the terrestrial planets. Such differences make them fascinating objects for study, providing clues about the origin and evolution of the planets and the formation of the solar system.

  4. Electrodynamics in Giant Planet Atmospheres

    NASA Astrophysics Data System (ADS)

    Koskinen, T.; Yelle, R. V.; Lavvas, P.; Cho, J.

    2014-12-01

    The atmospheres of close-in extrasolar giant planets such as HD209458b are strongly ionized by the UV flux of their host stars. We show that photoionization on such planets creates a dayside ionosphere that extends from the thermosphere to the 100 mbar level. The resulting peak electron density near the 1 mbar level is higher than that encountered in any planetary ionosphere of the solar system, and the model conductivity is in fact comparable to the atmospheres of Sun-like stars. As a result, the momentum and energy balance in the upper atmosphere of HD209458b and similar planets can be strongly affected by ion drag and resistive heating arising from wind-driven electrodynamics. Despite much weaker ionization, electrodynamics is nevertheless also important on the giant planets of the solar system. We use a generic framework to constrain the conductivity regimes on close-in extrasolar planets, and compare the results with conductivites based on the same approach for Jupiter and Saturn. By using a generalized Ohm's law and assumed magnetic fields, we then demonstrate the basic effects of wind-driven ion drag in giant planet atmospheres. Our results show that ion drag is often significant in the upper atmosphere where it can also substantially alter the energy budget through resistive heating.

  5. Migration of icy planetesimals to forming terrestrial planets

    NASA Astrophysics Data System (ADS)

    Ipatov, Sergei I.; Marov, Mikhail

    2016-07-01

    Our studies of migration of planetesimals from the feeding zone of Jupiter and Saturn to forming terrestrial planets were based on computer simulations of the orbital evolution of 10^4 planetesimals under the gravitational influence of planets. In series JN, all planets were considered in present orbits with present masses, and in series JS, Uranus and Neptune were excluded. Initial eccentricities and inclinations of planetesimals were 0.3 and 0.15 rad, respectively. Their initial semi-major axes were between 4.5 and 12 AU. Masses of planets moving in the orbits of the terrestrial planets were equal to present masses of the planets in series JS and JN, and were smaller by a factor of 10 in series JS_{01} and JN_{01}. The obtained results show that the ratio of the fraction of the planetesimals collided with an embryo of the Earth's embryo was about 2\\cdot10^{-6} and 4\\cdot10^{-7} for the mass of the embryo equal to the Earth mass and to 10% of the Earth mass, respectively. We concluded that during the growth of the mass of the Earth's embryo up to a half of the present mass of the Earth, the amount of water delivered to the embryo could be about 30% of all water delivered to the Earth from the feeding zone of Jupiter and Saturn. The total mass of water delivered to the Earth from the feeding zones of the giant planets and beyond these zones could be comparable with the mass of the Earth's oceans. A half of this water could come from the feeding zone of Jupiter and Saturn, and another half from more distant regions. Most of the water that was delivered from the distant regions to the Earth's embryo came when its mass was not small (e.g., was mainly greater than a half of the Earth mass). In series JS, the ratio of the mass of water delivered to a planet to the mass of the planet for the Earth was smaller by a factor of 2, 1.25, and 1.3 than for Mars, Venus and Mercury, respectively. For series JN, the above values of the factor were equal to 3.4, 0.7 i 0.8. For

  6. Homes for extraterrestrial life: extrasolar planets.

    PubMed

    Latham, D W

    2001-12-01

    Astronomers are now discovering giant planets orbiting other stars like the sun by the dozens. But none of these appears to be a small rocky planet like the earth, and thus these planets are unlikely to be capable of supporting life as we know it. The recent discovery of a system of three planets is especially significant because it supports the speculation that planetary systems, as opposed to single orbiting planets, may be common. Our ability to detect extrasolar planets will continue to improve, and space missions now in development should be able to detect earth-like planets.

  7. Popular Participation, Research and New Alliances.

    ERIC Educational Resources Information Center

    MacCall, Brian

    1981-01-01

    Suggests the need for more emphasis upon popular participation as a means of rural development. Proposes alliances between governments and people's organizations to cooperate in research, education and training, and mobilization. Describes contributions of international organizations toward this goal. (SK)

  8. G. P. Kuiper's Early Studies of Planets

    NASA Astrophysics Data System (ADS)

    Cruikshank, D. P.

    2005-08-01

    Gerard P. Kuiper was born on December 7, 1905; this is his centennial year. While he had an early interest in Solar System bodies, writing an extensive review about Mars for the popular Dutch astronomy journal, Hemel en Dampkring in 1931, Kuiper's first important observations began in 1944, when he discovered the atmosphere of Titan. In a letter dated February 29, 1944, to Lick Observatory director Joseph H. Moore, Kuiper noted that, ``The only reason I happened to observe the planets and the 10 brightest satellites was that they were nicely lined up in a region of the sky where I had run out of program stars (stars of large proper motion and parallax)." These spectroscopic observations were obtained with the new McDonald 82-inch telescope during a break from Kuiper's war-time work at Harvard's Radio Research Laboratory. In a letter of congratulations, his friend S. Chandrasekhar wrote, ``It is only on the impact of such discoveries that one realizes afresh the permanent value of science which no war -- not even of Hitler's -- can truly undermine. And it must be of satisfaction to you that if you took a vacation from war-work, it was only to make a fundamental discovery!" Using detectors declassified at the end of World War II, Kuiper began a study of the infrared spectra of planets and stars (with the first publication in 1947) that continued to the time of his death (December 24, 1973). Early in this work, on March 2, 1948, he wrote a lengthy letter to Henry Norris Russell in which he succinctly and enthusiastically summarized his observations and discoveries. Details in this letter give a fascinating perspective on some of the earliest physical studies of Solar System bodies, such as the detection of water ice on Saturn's rings and in the polar cap of Mars, spectral and photometric measurements of Mars' surface and atmospheric haze, and the discovery of Miranda.

  9. The Earth is a Planet Too!

    NASA Technical Reports Server (NTRS)

    Cairns, Brian

    2014-01-01

    When the solar system formed, the sun was 30 dimmer than today and Venus had an ocean. As the sun brightened, a runaway greenhouse effect caused the Venus ocean to boil away. At times when Earth was younger, the sun less bright, and atmospheric CO2 less, Earth froze over (snowball Earth). Earth is in the sweet spot today. Venus is closer to sun than Earth is, but cloud-covered Venus absorbs only 25 of incident sunlight, while Earth absorbs 70. Venus is warmer because it has a thick carbon dioxide atmosphere causing a greenhouse effect of several hundred degrees. Earth is Goldilocks choice among the planets, the one that is just right for life to exist. Not too hot. Not too cold. How does the Earth manage to stay in this habitable range? Is there a Gaia phenomenon keeping the climate in bounds? A nice idea, but it doesnt work. Today, greenhouse gas levels are unprecedented compared to the last 450,000 years.

  10. Planet Earth: Its Past, Our Present, A Future (?)

    NASA Astrophysics Data System (ADS)

    Kieffer, S. W.

    2012-04-01

    We who have lived through the second half of the 20th century into the 21st century have witnessed a profound transition in the biological and physical relationship between humans and the rest of the planet. In the middle of the last century, our planet still had undeveloped islands: there were frontiers that held new lands, mysteries, adventures, cultures, and resources. However, these islands have merged into a relatively seamless planet by a mobile and expanding population, science and technology, and global communication. We are subject to stealth as well as natural disasters. Natural disasters result from the ongoing geological and meteorological processes on our planet, increasingly exacerbated by human presence and behavior. Stealth disasters, on the other hand, are caused by humans, but involve the natural systems that support us. Examples of stealth disasters are climate change, loss of soils, acidification of the oceans, desertification, and loss of groundwater resources. Civilization is a complex system. It has emergent properties, and a tuning parameter--a parameter that is "tuned" until the unexpected happens. The tuning parameter for populations is the number of members relative to the capacities that support them. Because of our sheer numbers, we are driving the stealth disasters, and we will be affected more severely by natural disasters than we have been in the past on a less densely populated planet. To guide our thinking about geoethical issues, we propose a (hypothetical) world organization modeled after the Centers for Disease Control (CDC) in the U.S., and call it the Center for Disaster Control for Planet Earth (CDCPE). This center would have a scientific body to provide impartial facts and uncertainties, an engineering body to propose and implement technical solutions, a negotiating body to balance the realities of political, economic, religious and cultural values, and an enforcement body that is responsive to all of the inputs. How shall

  11. The atmospheres of earthlike planets after giant impact events

    SciTech Connect

    Lupu, R. E.; Freedman, Richard; Schaefer, Laura; Morley, Caroline; Fortney, Jonathan J.; Cahoy, Kerri

    2014-03-20

    It is now understood that the accretion of terrestrial planets naturally involves giant collisions, the moon-forming impact being a well-known example. In the aftermath of such collisions, the surface of the surviving planet is very hot and potentially detectable. Here we explore the atmospheric chemistry, photochemistry, and spectral signatures of post-giant-impact terrestrial planets enveloped by thick atmospheres consisting predominantly of CO{sub 2} and H{sub 2}O. The atmospheric chemistry and structure are computed self-consistently for atmospheres in equilibrium with hot surfaces with composition reflecting either the bulk silicate Earth (which includes the crust, mantle, atmosphere, and oceans) or Earth's continental crust. We account for all major molecular and atomic opacity sources including collision-induced absorption. We find that these atmospheres are dominated by H{sub 2}O and CO{sub 2}, while the formation of CH{sub 4} and NH{sub 3} is quenched because of short dynamical timescales. Other important constituents are HF, HCl, NaCl, and SO{sub 2}. These are apparent in the emerging spectra and can be indicative that an impact has occurred. The use of comprehensive opacities results in spectra that are a factor of two lower brightness temperature in the spectral windows than predicted by previous models. The estimated luminosities show that the hottest post-giant-impact planets will be detectable with near-infrared coronagraphs on the planned 30 m class telescopes. The 1-4 μm will be most favorable for such detections, offering bright features and better contrast between the planet and a potential debris disk. We derive cooling timescales on the order of 10{sup 5-6} yr on the basis of the modeled effective temperatures. This leads to the possibility of discovering tens of such planets in future surveys.

  12. The Atmospheres of Earthlike Planets after Giant Impact Events

    NASA Astrophysics Data System (ADS)

    Lupu, R. E.; Zahnle, Kevin; Marley, Mark S.; Schaefer, Laura; Fegley, Bruce; Morley, Caroline; Cahoy, Kerri; Freedman, Richard; Fortney, Jonathan J.

    2014-03-01

    It is now understood that the accretion of terrestrial planets naturally involves giant collisions, the moon-forming impact being a well-known example. In the aftermath of such collisions, the surface of the surviving planet is very hot and potentially detectable. Here we explore the atmospheric chemistry, photochemistry, and spectral signatures of post-giant-impact terrestrial planets enveloped by thick atmospheres consisting predominantly of CO2 and H2O. The atmospheric chemistry and structure are computed self-consistently for atmospheres in equilibrium with hot surfaces with composition reflecting either the bulk silicate Earth (which includes the crust, mantle, atmosphere, and oceans) or Earth's continental crust. We account for all major molecular and atomic opacity sources including collision-induced absorption. We find that these atmospheres are dominated by H2O and CO2, while the formation of CH4 and NH3 is quenched because of short dynamical timescales. Other important constituents are HF, HCl, NaCl, and SO2. These are apparent in the emerging spectra and can be indicative that an impact has occurred. The use of comprehensive opacities results in spectra that are a factor of two lower brightness temperature in the spectral windows than predicted by previous models. The estimated luminosities show that the hottest post-giant-impact planets will be detectable with near-infrared coronagraphs on the planned 30 m class telescopes. The 1-4 μm will be most favorable for such detections, offering bright features and better contrast between the planet and a potential debris disk. We derive cooling timescales on the order of 105-6 yr on the basis of the modeled effective temperatures. This leads to the possibility of discovering tens of such planets in future surveys.

  13. Demographic studies of extrasolar planets

    NASA Astrophysics Data System (ADS)

    Morton, Timothy

    Uncovering the demographics of extrasolar planets is crucial to understanding the processes of their formation and evolution. In this thesis, we present four studies that contribute to this end, three of which relate to NASA's Kepler mission, which has revolutionized the field of exoplanets in the last few years. In the pre-Kepler study, we investigate a sample of exoplanet spin-orbit measurements---measurements of the inclination of a planet's orbit relative to the spin axis of its host star---to determine whether a dominant planet migration channel can be identified, and at what confidence. Applying methods of Bayesian model comparison to distinguish between the predictions of several different migration models, we find that the data strongly favor a two-mode migration scenario combining planet-planet scattering and disk migration over a single-mode Kozai migration scenario. While we test only the predictions of particular Kozai and scattering migration models in this work, these methods may be used to test the predictions of any other spin-orbit misaligning mechanism. We then present two studies addressing astrophysical false positives in Kepler data. The Kepler mission has identified thousands of transiting planet candidates, and only relatively few have yet been dynamically confirmed as bona fide planets, with only a handful more even conceivably amenable to future dynamical confirmation. As a result, the ability to draw detailed conclusions about the diversity of exoplanet systems from Kepler detections relies critically on understanding the probability that any individual candidate might be a false positive. We show that a typical a priori false positive probability for a well-vetted Kepler candidate is only about 5-10%, enabling confidence in demographic studies that treat candidates as true planets. We also present a detailed procedure that can be used to securely and efficiently validate any individual transit candidate using detailed information of the

  14. Convection and plate tectonics on extrasolar planets

    NASA Astrophysics Data System (ADS)

    Sotin, C.; Grasset, O.; Schubert, G.

    2012-04-01

    The number of potential Earth-like exoplanets is still very limited compared to the overall number of detected exoplanets. But the different methods keep improving, giving hope for this number to increase significantly in the coming years. Based on the relationship between mass and radius, two of the easiest parameters that can be known for exoplanets, four categories of planets have been identified: (i) the gas giants including hot Jupiters, (ii) the icy giants that can be like their solar system cousins Uranus and Neptune or that can have lost their H2-He atmosphere and have become the so-called ocean planets, (iii) the Earth-like planets with a fraction of silicates and iron similar to that of the Earth, and (iv) the Mercury like planet that have a much larger fraction of iron. The hunt for exoplanets is very much focused on Earth-like planets because of the desire to find alien forms of life and the science goal to understand how life started and developed on Earth. One science question is whether heat transfer by subsolidus convection can lead to plate tectonics, a process that allows material to be recycled in the interior on timescales of hundreds of millions of years. Earth-like exoplanets may have conditions quite different from Earth. For example, COROT-7b is so close to its star that it is likely locked in synchronous orbit with one very hot hemisphere and one very cold hemisphere. It is also worth noting that among the three Earth-like planets of the solar system (Earth, Venus and Mars), only Earth is subject to plate tectonics at present time. Venus may have experienced plate tectonics before the resurfacing event that erased any clue that such a process existed. This study investigates some of the parameters that can influence the transition from stagnant-lid convection to mobile-lid convection. Numerical simulations of convective heat transfer have been performed in 3D spherical geometry in order to determine the stress field generated by convection

  15. Magnetic field of the planet Uranus: predictions, measurements, and interpretation

    SciTech Connect

    Dolginov, S.S.

    1987-09-01

    The magnitude and tilt of the eccentric dipole of Uranus are examined in the framework of a processing dynamo model. It is shown that the unique parameters of the magnetic field of Uranus are connected with the fact that, unlike the other planets, the magnetic field of Uranus is generated in two bordering regions whose highly conducting materials differ sharply in density: the density anti rho = 12 g x cm/sup -3/ in a core with an upper boundary r = 0.3R/sub U/, and anti rho = 3.1 g x cm/sup -3/ in an ocean with an upper boundary r = 0.6R/sub U/. The upper boundary of the magnetically active region in the ocean is determined by the magnetic pressure P = 1.9 Mbar, at which the ocean material is metallized.

  16. A Planet Found by Pulsations

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2016-10-01

    Searching for planets around very hot stars is much more challenging than looking around cool stars. For this reason, the recent discovery of a planet around a main-sequence A star is an important find both because of its unique position near the stars habitable zone, and because of the way in which the planet was discovered.Challenges in VariabilityIn the past three decades, weve discovered thousands of exoplanets yet most of them have been found around cool stars (like M dwarfs) or moderate stars (like G stars like our Sun). Very few of the planets that weve found orbit hot stars; in fact, weve only discovered ~20 planets orbiting the very hot, main-sequence A stars.The instability strip, indicated on an H-R diagram. Stellar classification types are listed across the bottom of the diagram. Many main-sequence A stars reside in the instability strip. [Rursus]Why is this? We dont expect that main-sequence A stars host fewer planets than cooler stars. Instead, its primarily because the two main techniques that we use to find planets namely, transits and radial velocity cant be used as effectively on the main-sequence A stars that are most likely to host planets, because the luminosities of these stars are often variable.These stars can lie on whats known as the classical instability strip in the Herzsprung-Russell diagram. Such variable stars pulsate due to changes in the ionization state of atoms deep in their interiors, which causes the stars to puff up and then collapse back inward. For variable main-sequence A stars, the periods for these pulsations can be several to several tens of times per day.These very pulsations that make transits and radial-velocity measurements so difficult, however, can potentially be used to detect planets in a different way. Led by Simon Murphy (University of Sydney, Australia and Aarhus University, Denmark), a team of scientists has recently detected the first planet ever to be discovered around a main-sequence A star from the timing

  17. GIANT PLANETS ORBITING METAL-RICH STARS SHOW SIGNATURES OF PLANET-PLANET INTERACTIONS

    SciTech Connect

    Dawson, Rebekah I.; Murray-Clay, Ruth A.

    2013-04-20

    Gas giants orbiting interior to the ice line are thought to have been displaced from their formation locations by processes that remain debated. Here we uncover several new metallicity trends, which together may indicate that two competing mechanisms deliver close-in giant planets: gentle disk migration, operating in environments with a range of metallicities, and violent planet-planet gravitational interactions, primarily triggered in metal-rich systems in which multiple giant planets can form. First, we show with 99.1% confidence that giant planets with semimajor axes between 0.1 and 1 AU orbiting metal-poor stars ([Fe/H] < 0) are confined to lower eccentricities than those orbiting metal-rich stars. Second, we show with 93.3% confidence that eccentric proto-hot Jupiters undergoing tidal circularization primarily orbit metal-rich stars. Finally, we show that only metal-rich stars host a pile-up of hot Jupiters, helping account for the lack of such a pile-up in the overall Kepler sample. Migration caused by stellar perturbers (e.g., stellar Kozai) is unlikely to account for the trends. These trends further motivate follow-up theoretical work addressing which hot Jupiter migration theories can also produce the observed population of eccentric giant planets between 0.1 and 1 AU.

  18. Visions of our Planet's Atmosphere, Land and Oceans

    NASA Technical Reports Server (NTRS)

    Hasler, A. F.

    2002-01-01

    The NASA/NOAA Electronic Theater presents Earth science observations and visualizations in a historical perspective. Fly in from outer space to South Africa, Cape Town and Johannesburg using NASA Terra/MODIS data, Landsat data and 1 m IKONOS 'Spy Satellite' data. Zoom in to any place South Africa using Earth Viewer 3D from Keyhole Inc. and Landsat data at 30 m resolution Go back to the early weather satellite images from the 1960s and see them contrasted with the latest US and international global satellite weather movies including hurricanes & 'tornadoes'. See the latest visualizations of spectacular images from NASANOAA remote sensing missions like Terra, GOES, TRMM, SeaWiFS, Landsat 7 including 1 - min GOES rapid scan image sequences of Nov 9th 2001 Midwest tornadic thunderstorms and have them explained.

  19. Magma Oceans on Exoplanets and Early Earth

    NASA Astrophysics Data System (ADS)

    Elkins-Tanton, Linda

    2009-09-01

    Late, giant accretionary impacts likely form multiple magma oceans of some depth in young rocky planets. Models of magma ocean solidification that incorporate water, carbon, and other incompatible volatile elements in small amounts predict a range of first-order outcomes important to planetary evolution. First, initial planetary bulk composition and size determine the composition of the earliest degassed atmosphere. This early atmosphere appears in a rapid burst at the end of solidification, determined by the ability of nucleating bubbles to reach the surface. Larger planets will have briefer and more catastrophic atmospheric degassing during solidification of any magma ocean. Second, this early atmosphere is sufficiently insulating to keep the planetary surface hot for millions of years. Depending upon the atmospheric composition and temperature structure these hot young planets may be observable from Earth or from satellites. Third, small but significant quantities of volatiles remain in the planet's solid mantle, encouraging convection, plate tectonics, and later atmospheric degassing through volcanism. A critical outcome of magma ocean solidification is the development of a solid mantle density gradient with den-sity increasing with radius, which will flow to gravitational stability. Shallow, dense, damp material will carry its water content as it sinks into the perovskite stability zone and transforms into perovskite. Even in models with very low initial water contents, a large fraction of the sinking upper mantle material will be forced to dewater as it crosses the boundary into the relatively dry lower mantle, leaving its water behind in a rapid flux as it sinks. This water ad-dition could initiate or speed convection in planets in which perovskite is stable, that is, planets larger than Mars.

  20. Terraforming planet Dune: Climate-vegetation interactions on a sandy planet

    NASA Astrophysics Data System (ADS)

    Cresto Aleina, F.; Baudena, M.; D'Andrea, F.; Provenzale, A.

    2012-04-01

    The climate and the biosphere of planet Earth interact in multiple, complicated ways and on many spatial and temporal scales. Some of these processes can be studied with the help of simple mathematical models, as done for the effects of vegetation on albedo in desert areas and for the mechanisms by which terrestrial vegetation affects water fluxes in arid environments. Conceptual models of this kind do not attempt at providing quantitative descriptions of the climate-biosphere interaction, but rather to explore avenues and mechanisms which can play a role in the real system, providing inspiration for further research. In this work, we develop a simple conceptual box model in the spirit illustrated above, to explore whether and how vegetation affects the planetary hydrologic cycle. We imagine a planet with no oceans and whose surface is entirely covered with sand, quite similar to planet Dune of the science-fiction series by Frank Herbert (1965). We suppose that water is entirely in the sand, below the surface. Without vegetation, only evaporation takes place, affecting the upper sand layer for a maximum depth of a few cm. The amount of water that is evaporated in the atmosphere is relatively small, and not sufficient to trigger a full hydrologic cycle. The question is what happens to this planet when vegetation is introduced: the root depth can reach a meter or more, and plant transpiration can then transfer a much larger amount of water to the atmosphere. One may wonder whether the presence of vegetation is sufficient to trigger a hydrologic cycle with enough precipitation to sustain the vegetation itself and, if the answer is positive, what is the minimum vegetation cover that is required to maintain the cycle active. In more precise terms, we want to know whether the introduction of vegetation and of the evapotranspiration feedback allows for the existence of multiple equilibria (or solutions) in the soil-vegetation-atmosphere system. Although the box model

  1. Habitability of planets on eccentric orbits: Limits of the mean flux approximation

    NASA Astrophysics Data System (ADS)

    Bolmont, Emeline; Libert, Anne-Sophie; Leconte, Jeremy; Selsis, Franck

    2016-06-01

    Unlike the Earth, which has a small orbital eccentricity, some exoplanets discovered in the insolation habitable zone (HZ) have high orbital eccentricities (e.g., up to an eccentricity of ~0.97 for HD 20782 b). This raises the question of whether these planets have surface conditions favorable to liquid water. In order to assess the habitability of an eccentric planet, the mean flux approximation is often used. It states that a planet on an eccentric orbit is called habitable if it receives on average a flux compatible with the presence of surface liquid water. However, because the planets experience important insolation variations over one orbit and even spend some time outside the HZ for high eccentricities, the question of their habitability might not be as straightforward. We performed a set of simulations using the global climate model LMDZ to explore the limits of the mean flux approximation when varying the luminosity of the host star and the eccentricity of the planet. We computed the climate of tidally locked ocean covered planets with orbital eccentricity from 0 to 0.9 receiving a mean flux equal to Earth's. These planets are found around stars of luminosity ranging from 1 L⊙ to 10-4L⊙. We use a definition of habitability based on the presence of surface liquid water, and find that most of the planets considered can sustain surface liquid water on the dayside with an ice cap on the nightside. However, for high eccentricity and high luminosity, planets cannot sustain surface liquid water during the whole orbital period. They completely freeze at apoastron and when approaching periastron an ocean appears around the substellar point. We conclude that the higher the eccentricity and the higher the luminosity of the star, the less reliable the mean flux approximation.

  2. NewsMars: Express journey to Mars ASE 2003: Knocked out by meteorites Events: Sun-Earth Day ASE 2003: Fun Physics - popular as ever Appointments: Sykes to bring science to the people UK Science Education: The future's bright, the future's science ASE 2003: A grand finale for Catherine Teaching Resources: UK goes to the planets Cambridge Physics Update: Basement physics Conferences: Earth Science Teachers' Association Conference 2003 New Website: JESEI sets sail GIREP: Teacher education seminar Malaysia: Rewards for curriculum change Cambridge Physics Update: My boomerang will come back! Teaching Resources: Widening particiption through ideas and evidence with the University of Surrey Wales: First Ffiseg Events: Nuna: Solar car on tour Physics on Stage: Physics on Stage 3 embraces life Symposium: In what sense a nuclear 'debate'? Gifted and Talented: Able pupils experiencing challenging science Australia: ISS flies high Down Under

    NASA Astrophysics Data System (ADS)

    2003-03-01

    Mars: Express journey to Mars ASE 2003: Knocked out by meteorites Events: Sun-Earth Day ASE 2003: Fun Physics - popular as ever Appointments: Sykes to bring science to the people UK Science Education: The future's bright, the future's science ASE 2003: A grand finale for Catherine Teaching Resources: UK goes to the planets Cambridge Physics Update: Basement physics Conferences: Earth Science Teachers' Association Conference 2003 New Website: JESEI sets sail GIREP: Teacher education seminar Malaysia: Rewards for curriculum change Cambridge Physics Update: My boomerang will come back! Teaching Resources: Widening particiption through ideas and evidence with the University of Surrey Wales: First Ffiseg Events: Nuna: Solar car on tour Physics on Stage: Physics on Stage 3 embraces life Symposium: In what sense a nuclear 'debate'? Gifted and Talented: Able pupils experiencing challenging science Australia: ISS flies high Down Under

  3. Reaching for the red planet

    PubMed

    David, L

    1996-05-01

    The distant shores of Mars were reached by numerous U.S. and Russian spacecraft throughout the 1960s to mid 1970s. Nearly 20 years have passed since those successful missions which orbited and landed on the Martian surface. Two Soviet probes headed for the planet in July, 1988, but later failed. In August 1993, the U.S. Mars Observer suddenly went silent just three days before it was to enter orbit around the planet and was never heard from again. In late 1996, there will be renewed activity on the launch pads with three probes departing for the red planet: 1) The U.S. Mars Global Surveyor will be launched in November on a Delta II rocket and will orbit the planet for global mapping purposes; 2) Russia's Mars '96 mission, scheduled to fly in November on a Proton launcher, consists of an orbiter, two small stations which will land on the Martian surface, and two penetrators that will plow into the terrain; and finally, 3) a U.S. Discovery-class spacecraft, the Mars Pathfinder, has a December launch date atop a Delta II booster. The mission features a lander and a microrover that will travel short distances over Martian territory. These missions usher in a new phase of Mars exploration, setting the stage for an unprecedented volley of spacecraft that will orbit around, land on, drive across, and perhaps fly at low altitudes over the planet.

  4. 3 CFR 8392 - Proclamation 8392 of June 12, 2009. National Oceans Month, 2009

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 3 The President 1 2010-01-01 2010-01-01 false Proclamation 8392 of June 12, 2009. National Oceans..., 2009 Proc. 8392 National Oceans Month, 2009By the President of the United States of America A Proclamation Oceans are the Earth's dominant feature. They cover more than 70 percent of the planet's...

  5. Ocean Fertilization and Ocean Acidification

    NASA Astrophysics Data System (ADS)

    Cao, L.; Caldeira, K.

    2008-12-01

    It has been suggested that ocean fertilization could help diminish ocean acidification. Here, we quantitatively evaluate this suggestion. Ocean fertilization is one of several ocean methods proposed to mitigate atmospheric CO2 concentrations. The basic idea of this method is to enhance the biological uptake of atmospheric CO2 by stimulating net phytoplankton growth through the addition of iron to the surface ocean. Concern has been expressed that ocean fertilization may not be very effective at reducing atmospheric CO2 concentrations and may produce unintended environmental consequences. The rationale for thinking that ocean fertilization might help diminish ocean acidification is that dissolved inorganic carbon concentrations in the near-surface equilibrate with the atmosphere in about a year. If ocean fertilization could reduce atmospheric CO2 concentrations, it would also reduce surface ocean dissolved inorganic carbon concentrations, and thus diminish the degree of ocean acidification. To evaluate this line of thinking, we use a global ocean carbon cycle model with a simple representation of marine biology and investigate the maximum potential effect of ocean fertilization on ocean carbonate chemistry. We find that the effect of ocean fertilization on ocean acidification depends, in part, on the context in which ocean fertilization is performed. With fixed emissions of CO2 to the atmosphere, ocean fertilization moderately mitigates changes in ocean carbonate chemistry near the ocean surface, but at the expense of further acidifying the deep ocean. Under the SRES A2 CO2 emission scenario, by year 2100 simulated atmospheric CO2, global mean surface pH, and saturation state of aragonite is 965 ppm, 7.74, and 1.55 for the scenario without fertilization and 833 ppm, 7.80, and 1.71 for the scenario with 100-year (between 2000 and 2100) continuous fertilization for the global ocean (For comparison, pre-industrial global mean surface pH and saturation state of

  6. Mercury - the hollow planet

    NASA Astrophysics Data System (ADS)

    Rothery, D. A.

    2012-04-01

    Mercury is turning out to be a planet characterized by various kinds of endogenous hole (discounting impact craters), which are compared here. These include volcanic vents and collapse features on horizontal scales of tens of km, and smaller scale depressions ('hollows') associated with bright crater-floor deposits (BCFD). The BCFD hollows are tens of metres deep and kilometres or less across and are characteristically flat-floored, with steep, scalloped walls. Their form suggests that they most likely result from removal of surface material by some kind of mass-wasting process, probably associated with volume-loss caused by removal (via sublimation?) of a volatile component. These do not appear to be primarily a result of undermining. Determining the composition of the high-albedo bluish surface coating in BCFDs will be a key goal for BepiColombo instruments such as MIXS (Mercury Imaging Xray Spectrometer). In contrast, collapse features are non-circular rimless pits, typically on crater floors (pit-floor craters), whose morphology suggests collapse into void spaces left by magma withdrawal. This could be by drainage of either erupted lava (or impact melt) or of shallowly-intruded magma. Unlike the much smaller-scale BCFD hollows, these 'collapse pit' features tend to lack extensive flat floors and instead tend to be close to triangular in cross-section with inward slopes near to the critical angle of repose. The different scale and morphology of BCFD hollows and collapse pits argues for quite different modes of origin. However, BCFD hollows adjacent to and within the collapse pit inside Scarlatti crater suggest that the volatile material whose loss was responsible for the growth of the hollows may have been emplaced in association with the magma whose drainage caused the main collapse. Another kind of volcanic collapse can be seen within a 25 km-wide volcanic vent outside the southern rim of the Caloris basin (22.5° N, 146.1° E), on a 28 m/pixel MDIS NAC image

  7. Growth of planets from planetesimals

    NASA Technical Reports Server (NTRS)

    Lissauer, Jack J.; Stewart, Glen R.

    1991-01-01

    The formation of terrestrial planets and the cores of Jovian planets is reviewed in the framework of the planetesimal hypothesis, wherein planets are assumed to grow via the pairwise accumulation of small solid bodies. The rate of (proto)planetary growth is determined by the size and mass of the protoplanet, the surface density of planetesimals, and the distribution of planetesimal velocities relative to the protoplanet. Planetesimal velocities are modified by mutual gravitational interactions and collisions, which convert energy present in the ordered relative motions of orbiting particles (Keplerian shear) into random motions and tend to reduce the velocities of the largest bodies in the swarm relative to those of smaller bodies, as well as by gas drag, which damps eccentricities and inclinations.

  8. Growth of planets from planetesimals

    NASA Technical Reports Server (NTRS)

    Lissauer, Jack J.; Stewart, Glen R.

    1993-01-01

    The paper reviews the formation of terrestrial planets and the cores of Jovian planets within the framework of the planetesimal hypothesis, wherein planets are assumed to grow via the pairwise accumulation of small solid bodies. The rate of (proto)planetary growth is determined by the size and mass of the protoplanet, the surface density of planetesimals, and the distribution of planetesimal velocities relative to the protoplanet. Planetesimal velocities are modified by mutual gravitational interactions and collisions, which convert energy present in the ordered relative motions of orbiting particles into random motions and tend to reduce the velocities of the largest bodies in the swarm relative to those of smaller bodies, as well as by gas drag, which damps eccentricities and inclinations. The evolution of planetesimal size distribution is determined by the gravitationally enhanced collision cross section, which favors collisions between planetesimals with smaller velocities.

  9. Extra-solar planet detection

    NASA Technical Reports Server (NTRS)

    Shao, Michael

    1991-01-01

    Extra-solar planet detection has been a goal of astronomers for many decades. This paper describes current efforts in planet detection using interferometric techniques. At present, the Mark III long baseline interferometer has been operational for a number of years. The Mark III has achieved significant improvement in astrometric accuracy in two areas, wide angle astrometry and double star astrometry. Two new interferometers are being developed. The first is a direct combination IR interferometer, an upgrade of the UCB IR heterodyne interferometer. The second is the Keck Interferometer Array. This instrument, to be operational at the end of the decade will be a major interferometric facility, with the capability to combine coherently the light from the two 10-meter Keck telescopes as well as four 1.5-meter movable outrigger telescopes. The last project directed at planet detection is OSI, a space-based long-baseline interferometer with a planned astrometric accuracy of 1-10 microarcsec.

  10. Hubble Extra Solar Planet Interferometer

    NASA Technical Reports Server (NTRS)

    Shao, M.

    1991-01-01

    This paper describes a proposed third-generation Hubble instrument for extra-solar planet detection, the Hubble Extra-Solar Planet Interferometer (HESPI). This instrument would be able to achieve starlight cancellation at the 10 exp 6 to 10 exp 8 level, given a stellar wavefront with phase errors comparable to the present Hubble telescope wavefront. At 10 exp 6 starlight cancellation, HESPI would be able to detect a Jupiter-like planet next to a star at a distance of about 10 parsec, for which there are about 400 candidate stars. This paper describes a novel approach for starlight suppression, using a combination of active control and single-mode spatial filters, to achieve starlight suppression far below the classical limit set by scattering due to microsurface imperfections. In preliminary lab experiments, suppression by a factor of 40 below the classical scatter limit due to optical wavefront errors has been demonstrated.

  11. Habitable zone limits for dry planets.

    PubMed

    Abe, Yutaka; Abe-Ouchi, Ayako; Sleep, Norman H; Zahnle, Kevin J

    2011-06-01

    Most discussion of habitable planets has focused on Earth-like planets with globally abundant liquid water. For an "aqua planet" like Earth, the surface freezes if far from its sun, and the water vapor greenhouse effect runs away if too close. Here we show that "land planets" (desert worlds with limited surface water) have wider habitable zones than aqua planets. For planets at the inner edge of the habitable zone, a land planet has two advantages over an aqua planet: (i) the tropics can emit longwave radiation at rates above the traditional runaway limit because the air is unsaturated and (ii) the dry air creates a dry stratosphere that limits hydrogen escape. At the outer limits of the habitable zone, the land planet better resists global freezing because there is less water for clouds, snow, and ice. Here we describe a series of numerical experiments using a simple three-dimensional global climate model for Earth-sized planets. Other things (CO(2), rotation rate, surface pressure) unchanged, we found that liquid water remains stable at the poles of a low-obliquity land planet until net insolation exceeds 415 W/m(2) (170% that of modern Earth), compared to 330 W/m(2) (135%) for the aqua planet. At the outer limits, we found that a low-obliquity land planet freezes at 77%, while the aqua planet freezes at 90%. High-obliquity land and aqua planets freeze at 58% and 72%, respectively, with the poles offering the last refuge. We show that it is possible that, as the Sun brightens, an aqua planet like Earth can lose most of its hydrogen and become a land planet without first passing through a sterilizing runaway greenhouse. It is possible that Venus was a habitable land planet as recently as 1 billion years ago.

  12. AN ULTRACOOL STAR'S CANDIDATE PLANET

    SciTech Connect

    Pravdo, Steven H.; Shaklan, Stuart B. E-mail: stuart.shaklan@jpl.nasa.gov

    2009-07-20

    We report here the discovery of the first planet around an ultracool dwarf star. It is also the first extrasolar giant planet astrometrically discovered around a main-sequence star. The statistical significance of the detection is shown in two ways. First, there is a 2 x 10{sup -8} probability that the astrometric motion fits a parallax-and-proper-motion-only model. Second, periodogram analysis shows a false alarm probability of 3 x 10{sup -5} that the discovered period is randomly generated. The planetary mass is M {sub 2} = 6.4 (+2.6,-3.1) Jupiter-masses (M {sub J}), and the orbital period is P = 0.744 (+0.013,-0.008) yr in the most likely model. In less likely models, companion masses that are higher than the 13 M {sub J} planetary mass limit are ruled out by past radial velocity (RV) measurements unless the system RV is more than twice the current upper limits and the near-periastron orbital phase was never observed. This new planetary system is remarkable, in part, because its star, VB 10, is near the lower mass limit for a star. Our astrometric observations provide a dynamical mass measurement and will in time allow us to confront the theoretical models of formation and evolution of such systems and their members. We thus add to the diversity of planetary systems and to the small number of known M-dwarf planets. Planets such as VB 10b could be the most numerous type of planets because M stars comprise >70% of all stars. To date they have remained hidden since the dominant RV planet-discovery technique is relatively insensitive to these dim, red systems.

  13. Habitable planets with high obliquities.

    PubMed

    Williams, D M; Kasting, J F

    1997-01-01

    Earth's obliquity would vary chaotically from 0 degrees to 85 degrees were it not for the presence of the Moon (J. Laskar, F. Joutel, and P. Robutel, 1993, Nature 361, 615-617). The Moon itself is thought to be an accident of accretion, formed by a glancing blow from a Mars-sized planetesimal. Hence, planets with similar moons and stable obliquities may be extremely rare. This has lead Laskar and colleagues to suggest that the number of Earth-like planets with high obliquities and temperate, life-supporting climates may be small. To test this proposition, we have used an energy-balance climate model to simulate Earth's climate at obliquities up to 90 degrees. We show that Earth's climate would become regionally severe in such circumstances, with large seasonal cycles and accompanying temperature extremes on middle- and high-latitude continents which might be damaging to many forms of life. The response of other, hypothetical, Earth-like planets to large obliquity fluctuations depends on their land-sea distribution and on their position within the habitable zone (HZ) around their star. Planets with several modest-sized continents or equatorial supercontinents are more climatically stable than those with polar supercontinents. Planets farther out in the HZ are less affected by high obliquities because their atmospheres should accumulate CO2 in response to the carbonate-silicate cycle. Dense, CO2-rich atmospheres transport heat very effectively and therefore limit the magnitude of both seasonal cycles and latitudinal temperature gradients. We conclude that a significant fraction of extrasolar Earth-like planets may still be habitable, even if they are subject to large obliquity fluctuations.

  14. Habitable planets with high obliquities

    NASA Technical Reports Server (NTRS)

    Williams, D. M.; Kasting, J. F.

    1997-01-01

    Earth's obliquity would vary chaotically from 0 degrees to 85 degrees were it not for the presence of the Moon (J. Laskar, F. Joutel, and P. Robutel, 1993, Nature 361, 615-617). The Moon itself is thought to be an accident of accretion, formed by a glancing blow from a Mars-sized planetesimal. Hence, planets with similar moons and stable obliquities may be extremely rare. This has lead Laskar and colleagues to suggest that the number of Earth-like planets with high obliquities and temperate, life-supporting climates may be small. To test this proposition, we have used an energy-balance climate model to simulate Earth's climate at obliquities up to 90 degrees. We show that Earth's climate would become regionally severe in such circumstances, with large seasonal cycles and accompanying temperature extremes on middle- and high-latitude continents which might be damaging to many forms of life. The response of other, hypothetical, Earth-like planets to large obliquity fluctuations depends on their land-sea distribution and on their position within the habitable zone (HZ) around their star. Planets with several modest-sized continents or equatorial supercontinents are more climatically stable than those with polar supercontinents. Planets farther out in the HZ are less affected by high obliquities because their atmospheres should accumulate CO2 in response to the carbonate-silicate cycle. Dense, CO2-rich atmospheres transport heat very effectively and therefore limit the magnitude of both seasonal cycles and latitudinal temperature gradients. We conclude that a significant fraction of extrasolar Earth-like planets may still be habitable, even if they are subject to large obliquity fluctuations.

  15. Space activities and global popular music culture

    NASA Astrophysics Data System (ADS)

    Wessels, Allison Rae; Collins, Patrick

    During the "space age" era, space activities appear increasingly as a theme in Western popular music, as they do in popular culture generally. In combination with the electronics and tele-communications revolution, "pop/rock" music has grown explosively during the space age to become an effectively global culture. From this base a number of trends are emerging in the pattern of influences that space activities have on pop music. The paper looks at the use of themes and imagery in pop music; the role of space technology in the modern "globalization" of pop music; and current and future links between space activities and pop music culture, including how public space programmes are affected by its influence on popular attitudes.

  16. Evolution of popularity in given names

    NASA Astrophysics Data System (ADS)

    Lee, Mi Jin; Jo, Woo Seong; Yi, Il Gu; Baek, Seung Ki; Kim, Beom Jun

    2016-02-01

    An individual's identity in a human society is specified by his or her name. Differently from family names, usually inherited from fathers, a given name for a child is often chosen at the parents' disposal. However, their decision cannot be made in a vacuum but affected by social conventions and trends. Furthermore, such social pressure changes in time, as new names gain popularity while some other names are gradually forgotten. In this paper, we investigate how popularity of given names has evolved over the last century by using datasets collected in Korea, the province of Quebec in Canada, and the United States. In each of these countries, the average popularity of given names exhibits typical patterns of rise and fall with a time scale of about one generation. We also observe that notable changes of diversity in given names signal major social changes.

  17. Radio Search For Extrasolar Planets

    NASA Astrophysics Data System (ADS)

    Zarka, P.

    Theoretical justification and ongoing observational efforts in view of detecting radio emissions from extrasolar planets will be presented. On the "prediction" side, a heuris- tic scaling law has been established relating the radio output of any magnetized flow- obstacle system to the incident magnetic energy flux on the obstacle. Its confirmation by the observation of radio emission from extrasolar planets would help to understand the energy budget of such a system. On the "detection" side, specific procedures have been developed for interference mitigation and weak burst detection.

  18. Return to the red planet

    NASA Astrophysics Data System (ADS)

    Nichols, Robert G.

    1992-10-01

    The paper discusses the type of data which will be collected by the NASA's Mars Observer spacecraft when it reaches the planet next year. These will include measurements on the Martian magnetic field, the volcanic activity, the dust storms, seasonal weather cycles, and the planet's atmosphere and gravitational field. The Mars Observer's instruments include a magnetometer, an electron reflectometer, an IR radiometer, a laser altimeter, a thermal-emission spectrometer, a gamma-ray spectrometer, a camera, and a radio system. The program is counting on the vehicle's longevity so that it can participate in a Russian mission due to arrive at Mars in September 1995.

  19. HUBBLE OBSERVES THE PLANET URANUS

    NASA Technical Reports Server (NTRS)

    2002-01-01

    This NASA Hubble Space Telescope image of the planet Uranus reveals the planet's rings and bright clouds and a high altitude haze above the planet's south pole. Hubble's new view was obtained on August 14, 1994, when Uranus was 1.7 billion miles (2.8 billion kilometers) from Earth. These details, as imaged by the Wide Field Planetary Camera 2, were only previously seen by the Voyager 2 spacecraft, which flew by Uranus in 1986. Since then, none of these inner satellites has been further observed, and detailed observations of the rings have not been possible. Though Uranus' rings were discovered indirectly in 1977 (through stellar occultation observations), they have never before been seen in visible light through a ground-based telescope. Hubble resolves several of Uranus' rings, including the outermost Epsilon ring. The planet has a total of 11 concentric rings of dark dust. Uranus is tipped such that its rotation axis lies in the plane of its orbit, so the rings appear nearly face-on. Three of Uranus' inner moons each appear as a string of three dots at the bottom of the picture. This is because the picture is a composite of three images, taken about six minutes apart, and then combined to show the moons' orbital motions. The satellites are, from left to right, Cressida, Juliet, and Portia. The moons move much more rapidly than our own Moon does as it moves around the Earth, so they noticeably change position over only a few minutes. One of the four gas giant planets of our solar system, Uranus is largely featureless. HST does resolve a high altitude haze which appears as a bright 'cap' above the planet's south pole, along with clouds at southern latitudes (similar structures were observed by Voyager). Unlike Earth, Uranus' south pole points toward the Sun during part of the planet's 84-year orbit. Thanks to its high resolution and ability to make observations over many years, Hubble can follow seasonal changes in Uranus's atmosphere, which should be unusual given

  20. Hubble Observes the Planet Uranus

    NASA Technical Reports Server (NTRS)

    1994-01-01

    This NASA Hubble Space Telescope image of the planet Uranus reveals the planet's rings and bright clouds and a high altitude haze above the planet's south pole.

    Hubble's new view was obtained on August 14, 1994, when Uranus was 1.7 billion miles (2.8 billion kilometers) from Earth. These details, as imaged by the Wide Field Planetary Camera 2, were only previously seen by the Voyager 2 spacecraft, which flew by Uranus in 1986. Since then, none of these inner satellites has been further observed, and detailed observations of the rings have not been possible.

    Though Uranus' rings were discovered indirectly in 1977 (through stellar occultation observations), they have never before been seen in visible light through a ground-based telescope.

    Hubble resolves several of Uranus' rings, including the outermost Epsilon ring. The planet has a total of 11 concentric rings of dark dust. Uranus is tipped such that its rotation axis lies in the plane of its orbit, so the rings appear nearly face-on.

    Three of Uranus' inner moons each appear as a string of three dots at the bottom of the picture. This is because the picture is a composite of three images, taken about six minutes apart, and then combined to show the moons' orbital motions. The satellites are, from left to right, Cressida, Juliet, and Portia. The moons move much more rapidly than our own Moon does as it moves around the Earth, so they noticeably change position over only a few minutes.

    One of the four gas giant planets of our solar system, Uranus is largely featureless. HST does resolve a high altitude haze which appears as a bright 'cap' above the planet's south pole, along with clouds at southern latitudes (similar structures were observed by Voyager). Unlike Earth, Uranus' south pole points toward the Sun during part of the planet's 84-year orbit. Thanks to its high resolution and ability to make observations over many years, Hubble can follow seasonal changes in Uranus's atmosphere, which should

  1. Chemical kinetics on extrasolar planets.

    PubMed

    Moses, Julianne I

    2014-04-28

    Chemical kinetics plays an important role in controlling the atmospheric composition of all planetary atmospheres, including those of extrasolar planets. For the hottest exoplanets, the composition can closely follow thermochemical-equilibrium predictions, at least in the visible and infrared photosphere at dayside (eclipse) conditions. However, for atmospheric temperatures approximately <2000K, and in the uppermost atmosphere at any temperature, chemical kinetics matters. The two key mechanisms by which kinetic processes drive an exoplanet atmosphere out of equilibrium are photochemistry and transport-induced quenching. I review these disequilibrium processes in detail, discuss observational consequences and examine some of the current evidence for kinetic processes on extrasolar planets.

  2. Atmospheric dynamics of tidally synchronized extrasolar planets.

    PubMed

    Cho, James Y-K

    2008-12-13

    Tidally synchronized planets present a new opportunity for enriching our understanding of atmospheric dynamics on planets. Subject to an unusual forcing arrangement (steady irradiation on the same side of the planet throughout its orbit), the dynamics on these planets may be unlike that on any of the Solar System planets. Characterizing the flow pattern and temperature distribution on the extrasolar planets is necessary for reliable interpretation of data currently being collected, as well as for guiding future observations. In this paper, several fundamental concepts from atmospheric dynamics, likely to be central for characterization, are discussed. Theoretical issues that need to be addressed in the near future are also highlighted.

  3. Books and the popularization of science

    USGS Publications Warehouse

    Buchanan, R.

    1991-01-01

    This article discusses best-selling science books, the characteristics of the audience for popular science books, and the role of books within science popularization and science education. Best-selling science books have been rare, but generally readable. Regional books, also important sources of scientific information, aim at much smaller, far more price-sensitive audiences. Many successful regional, nontechnical science books are readable, heavily illustrated, and in some cases, cross-disciplinary. To increase the attentive audience for scientific information, improvement in science education is necessary, and the most efficacious role for scientific institutions may be the production of materials that can be easily incorporated into school curricula. ?? 1991 Springer.

  4. Astronomy Popularization via Sci-fi Movies

    NASA Astrophysics Data System (ADS)

    Li, Qingkang

    2015-08-01

    It is astronomers’ duty to let more and more young people know a bit astronomy and be interested in astronomy and appreciate the beauty and great achievements in astronomy. One of the most effective methods to popularize astronomy to young people nowadays might be via enjoying some brilliant sci-fi movies related to astronomy with some guidance from astronomers. Firstly, we will introduce the basic information of our selective course “Appreciation of Sci-fi Movies in Astronomy” for the non-major astronomy students in our University, which is surely unique in China, then we will show its effect on astronomy popularization based on several rounds of teaching.

  5. The carbonate-silicate cycle and CO2/climate feedbacks on tidally locked terrestrial planets.

    PubMed

    Edson, Adam R; Kasting, James F; Pollard, David; Lee, Sukyoung; Bannon, Peter R

    2012-06-01

    Atmospheric gaseous constituents play an important role in determining the surface temperatures and habitability of a planet. Using a global climate model and a parameterization of the carbonate-silicate cycle, we explored the effect of the location of the substellar point on the atmospheric CO(2) concentration and temperatures of a tidally locked terrestrial planet, using the present Earth continental distribution as an example. We found that the substellar point's location relative to the continents is an important factor in determining weathering and the equilibrium atmospheric CO(2) level. Placing the substellar point over the Atlantic Ocean results in an atmospheric CO(2) concentration of 7 ppmv and a global mean surface air temperature of 247 K, making ∼30% of the planet's surface habitable, whereas placing it over the Pacific Ocean results in a CO(2) concentration of 60,311 ppmv and a global temperature of 282 K, making ∼55% of the surface habitable.

  6. FLIPPER: Validation for Remote Ocean Imaging

    NASA Technical Reports Server (NTRS)

    2006-01-01

    one of the determining factors in the planet s ability to support life is the same factor that makes the Blue Planet blue: water. Therefore, NASA researchers have a focused interest in understanding Earth s oceans and their ability to continue sustaining life. A critical objective in this study is to understand the global processes that control the changes of carbon and associated living elements in the oceans. Since oceans are so large, one of the most widely used methods of this research is remote sensing, using satellites to observe changes in the ocean color that may be indicative of changes occurring at the surface. Major changes in carbon are due to photosynthesis conducted by phytoplankton, showing, among other things, which areas are sustaining life. Although valuable for large-scale pictures of an ocean, remote sensing really only provides a surface, and therefore incomplete, depiction of that ocean s sustainability. True and complete testing of the water requires local testing in conjunction with the satellite images in order to generate the necessary algorithm parameters to calculate ocean health. For this reason, NASA has spearheaded research to provide onsite validation for its satellite imagery surveys.

  7. Wandering stars. About planets and exo-planets: an introductory notebook

    NASA Astrophysics Data System (ADS)

    Cole, George H. A.

    .5. Internal conditions: internal differentiation -- pt. III. Magnetism with the Solar System. 17. Intrinsic magnetism of the earth. 17.1. The magnetic poles. 17.2. The magnetic elements. 17.3. Separation into a dipole and non-dipole fields. 17.4. Short time variations: the secular variation. 17.5. Long time variations: magnetic field reversals. 17.6. The geomagnetic poles have moved: continental drift. 17.7. Creation of ocean floor. 18. The earth's external magnetism. 18.1. The effects of the solar emissions. 18.2. The interplanetary magnetic field. 18.3. The polar aurorae. 18.4. Magnetic storms and transient disturbances. 18.5. The special effect of the moon. 18.6. van Allen radiation belts. 19. The magnetism of the other planets. 19.1. The intrinsic magnetic fields. 19.2. The magnetosp

  8. Workshop on Oxygen in the Terrestrial Planets

    NASA Technical Reports Server (NTRS)

    2004-01-01

    This volume contains abstracts that have been accepted for presentation at the Workshop on Oxygen in the Terrestrial Planets, July 20-23,2004, Santa Fe, New Mexico. The contents include: 1) Experimental Constraints on Oxygen and Other Light Element Partitioning During Planetary Core Formation; 2) In Situ Determination of Fe(3+)/SigmaFe of Spinels by Electron Microprobe: An Evaluation of the Flank Method; 3) The Effect of Oxygen Fugacity on Large-Strain Deformation and Recrystallization of Olivine; 4) Plagioclase-Liquid Trace Element Oxygen Barometry and Oxygen Behaviour in Closed and Open System Magmatic Processes; 5) Core Formation in the Earth: Constraints from Ni and Co; 6) Oxygen Isotopic Compositions of the Terrestrial Planets; 7) The Effect of Oxygen Fugacity on Electrical Conduction of Olivine and Implications for Earth s Mantle; 8) Redox Chemical Diffusion in Silicate Melts: The Impact of the Semiconductor Condition; 9) Ultra-High Temperature Effects in Earth s Magma Ocean: Pt and W Partitioning; 10) Terrestrial Oxygen and Hydrogen Isotope Variations: Primordial Values, Systematics, Subsolidus Effects, Planetary Comparisons, and the Role of Water; 11) Redox State of the Moon s Interior; 12) How did the Terrestrial Planets Acquire Their Water?; 13) Molecular Oxygen Mixing Ratio and Its Seasonal Variability in the Martian Atmosphere; 14) Exchange Between the Atmosphere and the Regolith of Mars: Discussion of Oxygen and Sulfur Isotope Evidence; 15) Oxygen and Hydrogen Isotope Systematics of Atmospheric Water Vapor and Meteoric Waters: Evidence from North Texas; 16) Implications of Isotopic and Redox Heterogeneities in Silicate Reservoirs on Mars; 17) Oxygen Isotopic Variation of the Terrestrial Planets; 18) Redox Exchanges in Hydrous Magma; 19) Hydrothermal Systems on Terrestrial Planets: Lessons from Earth; 20) Oxygen in Martian Meteorites: A Review of Results from Mineral Equilibria Oxybarometers; 21) Non-Linear Fractionation of Oxygen Isotopes Implanted in

  9. THE ANGLO-AUSTRALIAN PLANET SEARCH. XXII. TWO NEW MULTI-PLANET SYSTEMS

    SciTech Connect

    Wittenmyer, Robert A.; Horner, J.; Salter, G. S.; Tinney, C. G.; Bailey, J.; Tuomi, Mikko; Zhang, Z.; Butler, R. P.; Jones, H. R. A.; O'Toole, S. J.; Carter, B. D.; Jenkins, J. S.; Vogt, S. S.; Rivera, Eugenio J.

    2012-07-10

    We report the detection of two new planets from the Anglo-Australian Planet Search. These planets orbit two stars each previously known to host one planet. The new planet orbiting HD 142 has a period of 6005 {+-} 427 days, and a minimum mass of 5.3 M{sub Jup}. HD 142c is thus a new Jupiter analog: a gas-giant planet with a long period and low eccentricity (e = 0.21 {+-} 0.07). The second planet in the HD 159868 system has a period of 352.3 {+-} 1.3 days and m sin i = 0.73 {+-} 0.05 M{sub Jup}. In both of these systems, including the additional planets in the fitting process significantly reduced the eccentricity of the original planet. These systems are thus examples of how multiple-planet systems can masquerade as moderately eccentric single-planet systems.

  10. Pragmatism and Popular Culture: Shusterman, Popular Art, and the Challenge of Visuality

    ERIC Educational Resources Information Center

    Snaevarr, Stefan

    2007-01-01

    In this article, the author discusses Richard Shusterman's defense of popular culture and intends to show that the entertainment industry has a dark side which Shusterman tends to ignore. Richard Shusterman is a pragmatist aesthetician who promotes art as an integral part of the ever-changing stream of life, believing that popular culture provides…

  11. ADDITIONAL OBSERVATIONS OF PLANETS AND QUASI-STELLAR RADIO SOURCES AT 3 MM,

    DTIC Science & Technology

    MERCURY ( PLANET ), VENUS( PLANET ), PERIODIC VARIATIONS, RADIO ASTRONOMY, SPECTRUM SIGNATURES...EXTRATERRESTRIAL RADIO WAVES, SOURCES), GALAXIES, BLACKBODY RADIATION, BRIGHTNESS, TEMPERATURE, MARS( PLANET ), JUPITER( PLANET ), SATURN( PLANET

  12. The differentiation history of the terrestrial planets as recorded on the moon

    SciTech Connect

    Borg, L

    2007-02-20

    The outline for this report is: (1) Factors Leading to Lunar Magma Ocean Model for Planetary Differentiation (2) Rationale for Magma Oceans on Other Planets Means for early efficient differentiation (Works on Moon why not here?) (3) Some Inconsistencies between the Lunar Magma Ocean Model and Observations. The conclusions are: (1) Differentiation via solidification of a magma ocean is derived from geologic observations of the Moon (2) Although geologic observations on other bodies are often consistent with differentiation via magma ocean solidification, it is not generally required. (3) There are some fundamental inconsistencies between observed lunar data and the model, that will require this model to be modified (4) Nevertheless, the Moon is the only location we know of to study magma ocean process in detail.

  13. The Sun, stars and planets (Christiaan Huygens Medal Lecture)

    NASA Astrophysics Data System (ADS)

    Bertaux, Jean-Loup

    2010-05-01

    Using stellar occultations as a tool to probe the planetary atmospheres has resulted in significant contributions to the exploration of our solar system. The technique of solar occultation has been well known for decades, but because of stars being so faint objects with respect to the Sun this technique was not very popular in the 70's. While fostering the idea of stellar occultations, I tried to avoid the unfortunate fate of Giordano Bruno, who was burned to death on February 17, 1600: he had dared to declare that the stars were objects like the sun, only much more remote. This talk will illustrate some results obtained by the star occultation technique by one scientific example on each of the three planets which are equipped with a stellar occultation instrument: GOMOS on ENVISAT (ozone monitoring), SPICAM on board Mars Express (temperature profiles), and SPICAV on Venus Express (SO2). I will also talk about Cristiaan Huygens, the first to discuss (according to the historical review of Pierre Connes) the problem of extra-solar planets in modern scientific terms which are still valid to day. Finally, I will address the threat to the planet Earth posed by Mankind, with some discussions about demography and geo-engineering.

  14. Scalable Regression Tree Learning on Hadoop using OpenPlanet

    SciTech Connect

    Yin, Wei; Simmhan, Yogesh; Prasanna, Viktor

    2012-06-18

    As scientific and engineering domains attempt to effectively analyze the deluge of data arriving from sensors and instruments, machine learning is becoming a key data mining tool to build prediction models. Regression tree is a popular learning model that combines decision trees and linear regression to forecast numerical target variables based on a set of input features. Map Reduce is well suited for addressing such data intensive learning applications, and a proprietary regression tree algorithm, PLANET, using MapReduce has been proposed earlier. In this paper, we describe an open source implement of this algorithm, OpenPlanet, on the Hadoop framework using a hybrid approach. Further, we evaluate the performance of OpenPlanet using realworld datasets from the Smart Power Grid domain to perform energy use forecasting, and propose tuning strategies of Hadoop parameters to improve the performance of the default configuration by 75% for a training dataset of 17 million tuples on a 64-core Hadoop cluster on FutureGrid.

  15. Elliptical instability in terrestrial planets and moons

    NASA Astrophysics Data System (ADS)

    Cebron, D.; Le Bars, M.; Moutou, C.; Le Gal, P.

    2012-03-01

    Context. The presence of celestial companions means that any planet may be subject to three kinds of harmonic mechanical forcing: tides, precession/nutation, and libration. These forcings can generate flows in internal fluid layers, such as fluid cores and subsurface oceans, whose dynamics then significantly differ from solid body rotation. In particular, tides in non-synchronized bodies and libration in synchronized ones are known to be capable of exciting the so-called elliptical instability, i.e. a generic instability corresponding to the destabilization of two-dimensional flows with elliptical streamlines, leading to three-dimensional turbulence. Aims: We aim here at confirming the relevance of such an elliptical instability in terrestrial bodies by determining its growth rate, as well as its consequences on energy dissipation, on magnetic field induction, and on heat flux fluctuations on planetary scales. Methods: Previous studies and theoretical results for the elliptical instability are re-evaluated and extended to cope with an astrophysical context. In particular, generic analytical expressions of the elliptical instability growth rate are obtained using a local WKB approach, simultaneously considering for the first time (i) a local temperature gradient due to an imposed temperature contrast across the considered layer or to the presence of a volumic heat source and (ii) an imposed magnetic field along the rotation axis, coming from an external source. Results: The theoretical results are applied to the telluric planets and moons of the solar system as well as to three Super-Earths: 55 CnC e, CoRoT-7b, and GJ 1214b. For the tide-driven elliptical instability in non-synchronized bodies, only the early Earth core is shown to be clearly unstable. For the libration-driven elliptical instability in synchronized bodies, the core of Io is shown to be stable, contrary to previously thoughts, whereas Europa, 55 CnC e, CoRoT-7b, and GJ 1214b cores can be unstable

  16. Tracking Planets around the Sun

    ERIC Educational Resources Information Center

    Riddle, Bob

    2008-01-01

    In earlier columns, the celestial coordinate system of hour circles of right ascension and degrees of declination was introduced along with the use of an equatorial star chart (see SFA Star Charts in Resources). This system shows the planets' motion relative to the ecliptic, the apparent path the Sun follows during the year. An alternate system,…

  17. TPF interferometer planet detection sensitivity

    NASA Astrophysics Data System (ADS)

    Elias, Nicholas M., II; Noecker, M. Charles

    2003-11-01

    Data-reduction algorithms for nulling interferometers can be divided into two categories, model-fitting and imaging. We deal mostly with single-Bracewell instruments because of their simplicity, even though they suffer from "nuisance sources" such as stellar leakage and exo-zodiacal light. To simplify data reduction, we work with the Fourier compo-nents of the time series. Exo-zodiacal light dominates at low frequencies. In principle, it should be possible to model the exo-zodiacal light contribution and separate it from planets using data from a single observation. In practice, however, the uncertainty in the exact form of the exo-zodiacal cloud limits our ability to model and remove its contribution. The only unambiguous way to detect planets with a single Bracewell is to observe a system multiple times through its orbit, and look for month-to-month variations in the Fourier components. To calculate the planet parameters, we discuss a cor-relation technique based on Fourier components instead of time series, in conjunction with a linearized least-squares so-lution. Because the fringe pattern on the sky is wavelength dependent, observations over multiple bandpasses signifi-cantly increases the confidence in planet detection. These algorithms may be used with other types of nulling interfer-ometers. We briefly discuss their application to dual Bracewell data.

  18. Do Other Planets Have Summer?

    ERIC Educational Resources Information Center

    Nelson, George

    2005-01-01

    It's important to keep two things in mind when thinking about the cause of the seasons: (1) Earth and all the other planets except Pluto and Mercury move around the Sun in almost perfect circles, getting neither closer nor farther away from the Sun during the year; and (2) Earth's rotation axis is tilted with respect to the plane of its orbit…

  19. Spectroscopic Observations of the Planets.

    DTIC Science & Technology

    2007-11-02

    1997). "The Surfaces of Pluto and Charon" D. P. Cruikshank, T. L. Roush, J. M. Moore, M. V. Sykes, T. Owen, M. J. Bartholomew, R. H. Brown, K. A...Tryka. In Pluto and Charon, ed. D. J. Tholen and S. A. Stern (Tucson, Univ. of Arizona Press) p. 221-268 (1997) . "From Planetesimals to Planets

  20. Terrestrial Planet Finder: science overview

    NASA Technical Reports Server (NTRS)

    Unwin, Stephen C.; Beichman, C. A.

    2004-01-01

    The Terrestrial Planet Finder (TPF) seeks to revolutionize our understanding of humanity's place in the universe - by searching for Earth-like planets using reflected light, or thermal emission in the mid-infrared. Direct detection implies that TPF must separate planet light from glare of the nearby star, a technical challenge which has only in recent years been recognized as surmountable. TPF will obtain a low-resolution spectra of each planets it detects, providing some of its basic physical characteristics and its main atmospheric constituents, thereby allowing us to assess the likelihood that habitable conditions exist there. NASA has decided the scientific importance of this research is so high that TPF will be pursued as two complementary space observatories: a visible-light coronagraph and a mid-infrared formation flying interferometer. The combination of spectra from both wavebands is much more valuable than either taken separately, and it will allow a much fuller understanding of the wide diversity of planetary atmospheres that may be expected to exist. Measurements across a broad wavelength range will yield not only physical properties such as size and albedo, but will also serve as the foundations of a reliable and robust assessment of habitability and the presence of life.

  1. Magnetosphere of the outer planets

    NASA Technical Reports Server (NTRS)

    Kennel, C. F.

    1972-01-01

    Scaling laws for possible outer planet magnetospheres are derived. These suggest that convection and its associated auroral effects will play a relatively smaller role than at earth, and that there is a possibility that they could have significant radiation belts of energetic trapped particles.

  2. Anderson testifies on Planet Earth

    NASA Astrophysics Data System (ADS)

    Wainger, Lisa A.

    AGU president Don Anderson joined former astronaut Sally Ride and National Aeronautics and Space Administration official Lennard Fisk March 8 in testifying before the Senate committee on Commerce, Science, and Transportation. The three had been asked to speak on the future of the Mission to Planet Earth, proposed both in a National Academy of Sciences report and a NASA study.Anderson was chairman of the National Academy of Science's Task Group on Earth Sciences, which prepared the report Mission to Planet Earth as part of the series Space Science in the Twenty-First Century. In his testimony, Anderson highlighted parts of the report and quoted the frontispiece “We now have the technology and the incentive to move boldly forward on a Mission to Planet Earth. We call on the nation to implement an integrated global program using both spaceborne and earth-based instrumentation for fundamental research on the origin, evolution and nature of our planet, its place in our solar system, and its interaction with living things, including mankind.”

  3. The Chemistry of the Planets.

    ERIC Educational Resources Information Center

    Blake, Peter

    1988-01-01

    Introduces knowledge of planetary chemistry for possible use in teaching. Discusses the chemical composition of the planets; the atmosphere and clouds of Venus, Jupiter and its moons, and Titan. Includes diagrams of the greenhouse effects in the solar system, elemental abundances, and the chemical composition of Jupiter. (RT)

  4. How Common are Habitable Planets?

    NASA Technical Reports Server (NTRS)

    Lissauer, Jack J.; DeVincenzi, Donald (Technical Monitor)

    2000-01-01

    The Earth is teeming with life, which, occupies a diverse array of environments; other bodies in our Solar System offer fewer, if any, niches which are habitable by life as we know it. Nonetheless, astronomical studies suggest that a large number of habitable planets-are likely to be present within our Galaxy.

  5. Giant Planets in Open Clusters

    NASA Astrophysics Data System (ADS)

    Quinn, S. N.; White, R. J.; Latham, D. W.

    2015-10-01

    Two decades after the discovery of 51 Peg b, more than 200 hot Jupiters have now been confirmed, but the details of their inward migration remain uncertain. While it is widely accepted that short period giant planets could not have formed in situ, several different mechanisms (e.g., Type II migration, planet-planet scattering, Kozai-Lidov cycles) may contribute to shrinking planetary orbits, and the relative importance of each is not well-constrained. Migration through the gas disk is expected to preserve circular, coplanar orbits and must occur quickly (within ˜ 10 Myr), whereas multi-body processes should initially excite eccentricities and inclinations and may take hundreds of millions of years. Subsequent evolution of the system (e.g., orbital circularization and inclination damping via tidal interaction with the host star) may obscure these differences, so observing hot Jupiters soon after migration occurs can constrain the importance of each mechanism. Fortunately, the well-characterized stars in young and adolescent open clusters (with known ages and compositions) provide natural laboratories for such studies, and recent surveys have begun to take advantage of this opportunity. We present a review of the discoveries in this emerging realm of exoplanet science, discuss the constraints they provide for giant planet formation and migration, and reflect on the future direction of the field.

  6. Finding Spring on Planet X

    ERIC Educational Resources Information Center

    Simoson, Andrew J.

    2007-01-01

    For a given orbital period and eccentricity, we determine the maximum time lapse between the winter solstice and the spring equinox on a planet. In addition, given an axial precession path, we determine the effects on the seasons. This material can be used at various levels to illustrate ideas such as periodicity, eccentricity, polar coordinates,…

  7. Venus and Mercury as Planets

    NASA Technical Reports Server (NTRS)

    1974-01-01

    A general evolutionary history of the solar planetary system is given. The previously observed characteristics of Venus and Mercury (i.e. length of day, solar orbit, temperature) are discussed. The role of the Mariner 10 space probe in gathering scientific information on the two planets is briefly described.

  8. Jupiter: Lord of the Planets.

    ERIC Educational Resources Information Center

    Kaufmann, William

    1984-01-01

    Presents a chapter from an introductory college-level astronomy textbook in which full-color photographs and numerous diagrams highlight an extensive description of the planet Jupiter. Topics include Jupiter's geology, rotation, magnetic field, atmosphere (including clouds and winds), and the Great Red Spot. (DH)

  9. A window for plate tectonics in terrestrial planet evolution?

    NASA Astrophysics Data System (ADS)

    O'Neill, Craig; Lenardic, Adrian; Weller, Matthew; Moresi, Louis; Quenette, Steve; Zhang, Siqi

    2016-06-01

    The tectonic regime of a planet depends critically on the contributions of basal and internal heating to the planetary mantle, and how these evolve through time. We use viscoplastic mantle convection simulations, with evolving core-mantle boundary temperatures, and radiogenic heat decay, to explore how these factors affect tectonic regime over the lifetime of a planet. The simulations demonstrate (i) hot, mantle conditions, coming out of a magma ocean phase of evolution, can produce a "hot" stagnant-lid regime, whilst a cooler post magma ocean mantle may begin in a plate tectonic regime; (ii) planets may evolve from an initial hot stagnant-lid condition, through an episodic regime lasting 1-3 Gyr, into a plate-tectonic regime, and finally into a cold, senescent stagnant lid regime after ∼10 Gyr of evolution, as heat production and basal temperatures wane; and (iii) the thermal state of the post magma ocean mantle, which effectively sets the initial conditions for the sub-solidus mantle convection phase of planetary evolution, is one of the most sensitive parameters affecting planetary evolution - systems with exactly the same physical parameters may exhibit completely different tectonics depending on the initial state employed. Estimates of the early Earth's temperatures suggest Earth may have begun in a hot stagnant lid mode, evolving into an episodic regime throughout most of the Archaean, before finally passing into a plate tectonic regime. The implication of these results is that, for many cases, plate tectonics may be a phase in planetary evolution between hot and cold stagnant states, rather than an end-member.

  10. Planet Press: an EGU initiative to bring geoscientific research to children

    NASA Astrophysics Data System (ADS)

    Ferreira, Bárbara

    2016-04-01

    Planet Press (http://www.egu.eu/education/planet-press/) is an EGU educational project that aims to get children (mainly 7-13 year olds), as well as their parents and educators, interested in and engaged with up-to-date scientific research and news. Planet Press articles are short versions of EGU press releases written in child-friendly language. Because EGU press releases cover research published in the various EGU scientific journals, Planet Press focuses on topics as varied as air pollution, glaciers, climate change, earthquakes, ocean sciences, droughts and floods, or space sciences. The texts are reviewed by both scientists and educators to make sure they are accurate and clear to their target audience. By sharing new and exciting geoscientific research with young kids, we hope to inspire them to develop an interest in the Earth, planetary and space sciences. In this presentation, we describe how the Planet Press idea came about, how the project is run, and the challenges and lessons learnt since the launch of this educational initiative in 2014. Planet Press, which has the support of the EGU Committee on Education, is made possible by the work of volunteer scientists and educators who review and translate the texts. We are grateful for the help of Jane Robb, former EGU Educational Fellow, with launching the project. Planet Press is inspired by Space Scoop (http://www.spacescoop.org/), an initiative by UNAWE, the EU-Universe Awareness organisation, that brings astronomy news to children every week.

  11. UWP 011: Popular Science and Technology Writing

    ERIC Educational Resources Information Center

    Perrault, Sarah

    2012-01-01

    UWP 011: Popular Science & Technology Writing is a sophomore-level course designed as an introduction to rhetoric of science at UC Davis, a science-focused land-grant university. The course fulfills the general education requirements for written literacy and for topical breadth in arts and humanities. The catalog describes the course as…

  12. Predicting Bullying: Maladjustment, Social Skills and Popularity

    ERIC Educational Resources Information Center

    Postigo, Silvia; Gonzalez, Remedios; Mateu, Carmen; Montoya, Inmaculada

    2012-01-01

    In order to prevent bullying, research has characterised the adolescents involved in terms of their social skills, maladjustment and popularity. However, there is a lack of knowledge concerning the relationships between these variables and how these relationships predict bullying involvement. Moreover, the literature has focused on pure bullies…

  13. Popular Music, Television, and Generational Identity.

    ERIC Educational Resources Information Center

    Burns, Gary

    Although previous generations have by no means been disloyal to the popular music of their youth, the tenacious attachment of the Baby Boomers to the music of the 1960s seems unprecedented. Three main reasons account for this constantly widening musical reclamation project. First, the Baby Boomers have a clearer sense of generational identity that…

  14. Misreading Masculinity: Boys, Literacy, and Popular Culture.

    ERIC Educational Resources Information Center

    Newkirk, Thomas

    This book takes an up-close and personal look at elementary school boys and their relationship to sports, movies, video games, and other avenues of popular culture. The book views these media not as enemies of literacy, but as resources "for" literacy. It contains a series of interviews with young boys and girls who describe the pleasure…

  15. The Guide to Teaching with Popular Music.

    ERIC Educational Resources Information Center

    Music Educators National Conference, Reston, VA.

    Popular music is often characterized as a short work with a prominent melody and simple chordal accompaniment. Yet, teaching with pop music in the era of standards-based curriculum can present challenges. These standards offer teachers a blueprint for teaching music performance, composition, improvisation, and the relationship of music to other…

  16. Human urinary parasites in Nalout popularity, Libya.

    PubMed

    Al Kilani, M K; Dahesh, S M; El Taweel, H A

    2008-08-01

    A total of 2000 fresh urine samples were collected from a central private laboratory in Tigi Conference which served all the popularity. The examination showed motile Trichomonas vaginalis in seven patients (0.35%); five females and two males, and Enterobius vermicularis in two female children (0.1%). None had urinary schistosomiasis. The data were discussed.

  17. Popularity and user diversity of online objects

    NASA Astrophysics Data System (ADS)

    Wang, Jia-Hua; Guo, Qiang; Yang, Kai; Zhang, Yi-Lu; Han, Jingti; Liu, Jian-Guo

    2016-11-01

    The popularity has been widely used to describe the object property of online user-object bipartite networks regardless of the user characteristics. In this paper, we introduce a measurement namely user diversity to measure diversity of users who select or rate one type of objects by using the information entropy. We empirically calculate the user diversity of objects with specific degree for both MovieLens and Diggs data sets. The results indicate that more types of users select normal-degree objects than those who select large-degree and small-degree objects. Furthermore, small-degree objects are usually selected by large-degree users while large-degree objects are usually selected by small-degree users. Moreover, we define 15% objects of smallest degrees as unpopular objects and 10% ones of largest degrees as popular objects. The timestamp is introduced to help further analyze the evolution of user diversity of popular objects and unpopular objects. The dynamic analysis shows that as objects become popular gradually, they are more likely accepted by small-degree users but lose attention among the large-degree users.

  18. Popular Education and the Logics of Schooling

    ERIC Educational Resources Information Center

    Rockwell, Elsie

    2011-01-01

    In this article, I compare two distinct uses of "Popular Education" that emerged in Tlaxcala in the wake of the Mexican Revolution. I examine archival and oral evidence to reconstruct the situated meanings and political rationales that led to the use of the term in each case, beyond their contrasting pedagogical content. In 1917, a…

  19. Using Popular Children's Films in Science

    ERIC Educational Resources Information Center

    Wadsworth, Elle; Croker, Stev; Harrison, Tim

    2012-01-01

    Watching films is a common activity for children outside of school, and incorporating popular films that contain scientific references has the potential to spark interest in the classroom. Clips rather than entire films can be used, as the children will maintain focus on the lesson objectives while being excited by the appeal of the film. The use…

  20. Popular Literature: Its Compatibility with the Basics.

    ERIC Educational Resources Information Center

    Matthews, Dorothy, Ed.

    1983-01-01

    This special journal issue contains nine articles on the subject of using popular literature in the classroom. Subjects covered in the articles include (1) using vernacular supernatural literature to teach the skills of literary analysis, (2) teaching Agatha Christie's "Curtain," (3) pairing the classics with detective fiction, (4) using fantasy…

  1. The Nature of Science in Popular Nonfiction

    ERIC Educational Resources Information Center

    Austin, Barbara; Menasco, Jackie; Vannette, Trenda

    2008-01-01

    To help make science relevant to student's everyday lives, the authors required their 10th-grade summer school students to read selections from a popular nonfiction science book. By doing so, they were able to promote literacy and provide an authentic portrayal of the nature of science in a way that was fun and interesting for their students. This…

  2. Is Good, Popular Science Television Possible?

    ERIC Educational Resources Information Center

    Mosley, Michael

    1988-01-01

    Describes the work behind one successful popular science program which does not trivialize the image of science. Discusses areas including science and broadcasting, one of the longest running science and technology programs on television, the mass media and health, and media fellowships for scientists. (RT)

  3. Caveat Lector: Reviewing Popular Social Science.

    ERIC Educational Resources Information Center

    Hixson, Vivian Scott

    1981-01-01

    Discusses problems with reviews and criticisms of popular social science books: the quality and background of reviewers, the difficulty of distinguishing between fact and opinion, and the scarcity of competent reviewers. Analyzes reviews of Robert Ardrey's "African Genesis" and "The Territorial Imperative," Konrad Lorenz's "On Aggression," and…

  4. Teaching Theory through Popular Culture Texts

    ERIC Educational Resources Information Center

    Trier, James

    2007-01-01

    In this article, the author describes a pedagogical approach to teaching theory to pre-service teachers. This approach involves articulating academic texts that introduce theoretical ideas and tools with carefully selected popular culture texts that can be taken up to illustrate the elements of a particular theory. Examples of the theories…

  5. American Popular Music 1950-2000

    ERIC Educational Resources Information Center

    Lonergan, David

    2011-01-01

    This article describes and discusses some of the chief resources in the study of post-World War II mainstream popular music. In addition to indicating major areas of research, it can serve as a guide to collection development in the discipline.

  6. Student Voice and the Perils of Popularity

    ERIC Educational Resources Information Center

    Rudduck, Jean; Fielding, Michael

    2006-01-01

    In this article we suggest that the current popularity of student voice can lead to surface compliance--to a quick response that focuses on "how to do it" rather than a reflective review of "why we might want to do it". We look at the links between student consultation and participation and the legacy of the progressive democratic tradition in our…

  7. Understanding and Developing Black Popular Music Collections.

    ERIC Educational Resources Information Center

    Murray, James Briggs

    1983-01-01

    Enumerates types of black popular music (work songs, spirituals, gospel music, blues, race records, rock and roll, soul, funk, disco, Caribbean, and African) and discusses collection development (current, retrospective, monographs, periodicals, sheet music, motion picture film, photographs, oral history), cataloging, and preservation. A 229-item…

  8. Is Being Popular a Risky Proposition?

    ERIC Educational Resources Information Center

    Mayeux, Lara; Sandstrom, Marlene J.; Cillessen, Antonius H. N.

    2008-01-01

    Longitudinal associations between social preference, perceived popularity, and risk behaviors (smoking, alcohol use, and sexual activity) were examined in a sample of high school students. Social preference did not predict any of the risk behaviors assessed, although the interaction between gender and social preference was predictive of sexual…

  9. Popular Media and the Teenage Sexual Agenda.

    ERIC Educational Resources Information Center

    Strover, Sharon

    A qualitative study examined how teenagers react to and interpret certain popular media messages. In addition it explored the relationship between content containing various sexual messages and teenagers' responses to those messages, with particular attention to the critical abilities this audience exhibits. Fifty male and female teenagers aged…

  10. Shakespeare Cereals: A Popular Culture Exercise.

    ERIC Educational Resources Information Center

    Schiff, Peter

    1997-01-01

    Offers an exercise involving popular culture to help students experience the contemporary power of Shakespeare. Explains that after reading a Shakespeare play, students develop new cereal brands based upon the work's plot, characters, or themes, afterward naming, designing, creating, and displaying the cereal package. Combines literary analysis,…

  11. Outlook: Testing Planet Formation Theories

    NASA Astrophysics Data System (ADS)

    Boss, A. P.

    The discovery of the first planetary companion to a solar-type star by Mayor and Queloz (1995) launched the extrasolar planetary systems era. Observational and theoretical progress in this area has been made at a breathtaking pace since 1995, as evidenced by this workshop. We now have a large and growing sample of extrasolar gas giant planets with which to test our theories of their formation and evolution. The two competing theories for the formation of gas giant planets, core accretion and disk instability, appear to have testable predictions: (i) Core accretion seems to require exceptionally long-lived disks, implying that gas giants should be somewhat rare, while disk instability can occur in even the shortest-lived disk, implying that gas giants should be abundant. The ongoing census of gas giants by the spectroscopic search programs will determine the frequency of gas giants on Jupiter-like orbits within the next decade. (ii) Core accretion takes millions of years to form gas giants, while disk instability forms gaseous protoplanets in thousands of years. Determining the epoch of gas giant planet formation by searching for astrometric wobbles indicative of gas giant companions around young stars with a range of ages (˜ 0.1 Myr to ˜ 10 Myr) should be possible with the Space Interferometry Mission (SIM). (iii) Core accretion would seem to be bolstered by a higher ratio of dust to gas, whereas disk instability occurs equally well for a range of dust opacities. Determining whether a high primordial metallicity is necessary for gas giant planet formation can be accomplished by spectroscopic and astrometric searches for gas giants around metal-poor stars. Eventually, ice giant planets will be detectable as well. If ice giants are found to be much more frequent that gas giants, this may imply that core accretion occurs, but usually fails to form a gas giant. Terrestrial planets will be detected through photometry by Kepler and Eddington, astrometry by SIM, and

  12. How climate evolved on the terrestrial planets.

    PubMed

    Kasting, J F; Toon, O B; Pollack, J B

    1988-02-01

    Planets with temperate, earthlike climates were once thought to be rare in our galaxy. Mathematical models now suggest that if planets do exist outside the solar system, many of them might be habitable.

  13. The Geology of the Terrestrial Planets

    NASA Technical Reports Server (NTRS)

    Carr, M. H. (Editor); Saunders, R. S.; Strom, R. G.; Wilhelms, D. E.

    1984-01-01

    The geologic history of the terrestrial planets is outlined in light of recent exploration and the revolution in geologic thinking. Among the topics considered are planet formation; planetary craters, basins, and general surface characteristics; tectonics; planetary atmospheres; and volcanism.

  14. Kepler Discovers Earth-size Planet Candidates

    NASA Video Gallery

    NASA's Kepler mission has discovered its first Earth-size planet candidates and its first candidates in the habitable zone, a region where liquid water could exist on a planet's surface. Five of th...

  15. Tour of Planet With Extreme Temperature Swings

    NASA Video Gallery

    A computer simulation of the planet HD 80606b. The point of closest approach -- and maximum heating -- occurs about 4.5 seconds into the animation. As the planet whips around the star, we see the e...

  16. Formation of the terrestrial planets from planetesimals

    NASA Technical Reports Server (NTRS)

    Wetherill, George W.

    1991-01-01

    Formation of the terrestrial planets from planetesimals is discussed. The following subject areas are covered: (1) formation of the original planetesimals; (2) growth of planetesimals into planetary embryos; and (3) growth of runaway planetary embryos into terrestrial planets.

  17. Kepler Discovers Its First Rocky Planet

    NASA Video Gallery

    NASA's Kepler mission confirmed the discovery of its first rocky planet, named Kepler-10b. Measuring 1.4 times the size of Earth, it is the smallest planet ever discovered outside our solar system....

  18. Extreme Adaptive Optics Planet Imager

    NASA Astrophysics Data System (ADS)

    Macintosh, B.; Graham, J. R.; Ghez, A.; Kalas, P.; Lloyd, J.; Makidon, R.; Olivier, S.; Patience, J.; Perrin, M.; Poyneer, L.; Severson, S.; Sheinis, A.; Sivaramakrishnan, A.; Troy, M.; Wallace, J.; Wilhelmsen, J.

    2002-12-01

    Direct detection of photons emitted or reflected by extrasolar planets is the next major step in extrasolar planet studies. Current adaptive optics (AO) systems, with <300 subapertures and Strehl ratio 0.4-0.7, can achieve contrast levels of 106 at 2" separations; this is sufficient to see very young planets in wide orbits but insufficient to detect solar systems more like our own. Contrast levels of 107 - 108 in the near-IR are needed to probe a significant part of the extrasolar planet phase space. The NSF Center for Adaptive Optics is carrying out a design study for a dedicated ultra-high-contrast "Extreme" adaptive optics system for an 8-10m telescope. With 3000 controlled subapertures it should achieve Strehl ratios > 0.9 in the near-IR. Using a spatially filtered wavefront sensor, the system will be optimized to control scattered light over a large radius and suppress artifacts caused static errors. We predict that it will achieve contrast levels of 107-108 around a large sample of stars (R<7-10), sufficient to detect Jupiter-like planets through their near-IR emission over a wide range of ages and masses. The system will be capable of a variety of high-contrast science including studying circumstellar dust disks at densities a factor of 10-100 lower than currently feasible and a systematic inventory of other solar systems on 10-100 AU scale. This work was supported by the NSF Science and Technology Center for Adaptive Optics, managed by UC Santa Cruz under AST-9876783. Portions of this work was performed under the auspices of the U.S. Department of Energy, under contract No. W-7405-Eng-48.

  19. Origin of the earth's ocean basins

    NASA Technical Reports Server (NTRS)

    Frey, H.

    1977-01-01

    The earth's original ocean basins are proposed to be mare-type basins produced 4 billion y.a. by the flux of asteroid-sized objects responsible for the lunar mare basins. Scaling upward from the observed number of lunar basins for the greater capture cross-section and impact velocity of the earth indicates that at least 50% of an original global crust would have been converted to basin topography. These basins were flooded by basaltic liquids in times short compared to the isostatic adjustment time for the basin. The modern crustal dichotomy (60% oceanic, 40% continental crust) was established early in the history of the earth, making possible the later onset of plate tectonic processes. These later processes have subsequently reworked, in several cycles, principally the oceanic parts of the earth's crust, changing the configuration of the continents in the process. Ocean basins (and oceans themselves) may be rare occurrences on planets in other star systems.

  20. Origin of the earth's ocean basins

    NASA Technical Reports Server (NTRS)

    Frex, H.

    1977-01-01

    The earth's original ocean basins were mare-type basins produced 4 billion years ago by the flux of asteroid-sized objects responsible for the lunar mare basins. Scaling upwards from the observed number of lunar basins for the greater capture cross-section and impact velocity of the Earth indicates that at least 50 percent of an original global crust would have been converted to basin topography. These basins were flooded by basaltic liquids in times short compared to the isostatic adjustment time for the basin. The modern crustal dichotomy (60 percent oceanic, 40 percent continental crust) was established early in the history of the earth, making possible the later onset of plate tectonic processes. These later processes have subsequently reworked, in several cycles, principally the oceanic parts of the earth's crust, changing the configuration of the continents in the process. Ocean basins (and oceans themselves) may be rare occurrences on planets in other star systems.

  1. Progress in extra-solar planet detection

    NASA Technical Reports Server (NTRS)

    Brown, Robert A.

    1991-01-01

    Progress in extra-solar planet detection is reviewed. The following subject areas are covered: (1) the definition of a planet; (2) the weakness of planet signals; (3) direct techniques - imaging and spectral detection; and (4) indirect techniques - reflex motion and occultations.

  2. The Use of Planisphere to Locate Planets

    ERIC Educational Resources Information Center

    Kwok, Ping-Wai

    2013-01-01

    Planisphere is a simple and useful tool in locating constellations of the night sky at a specific time, date and geographic location. However it does not show the planet positions because planets are not fixed on the celestial sphere. It is known that the planet orbital planes are nearly coplanar and close to the ecliptic plane. By making…

  3. The evolution of ocean color

    NASA Astrophysics Data System (ADS)

    Gallardo, Victor A.; Espinoza, Carola

    2008-08-01

    Analog examples of what primeval oceans might have looked in the Precambrian are probably extant in various regions and at various size scales in present day oceans albeit they have not been sufficiently recognized and/or studied. The Eastern Boundary Current Ecosystems (EBCEs), with their characteristic high productivity-inducing coastal upwelling events, their extensive and intensive anoxic/hypoxic water column and methane and sulfide-rich benthic environment, appear to represent such analogs. Moreover, recent studies have shown that they possess diverse anaerobic prokaryotic communities of mat-forming large multi-cellular filamentous bacteria similar to fossils found in Archean and Proterozoic rocks. Observations in the Bay of Concepcion, central Chile (~36°S), inserted in the second most productive EBCE of the world, suggests that given similar oceanographic dynamics, past oceans may have presented different predominant colorations after the first probable "red" color of the reduced iron-rich Archean ocean and prior to the present day "blue" color. In this coastal ecosystem a "black" coloration has been observed to form as the result of the floating to the surface layer of sulfide-blackened benthic detritus together with chunks of microbial mats, and a "milky to turquoise" coloration resulting from different concentrations of colloidal, nano-sized particles which may include elemental sulfur and/or microorganisms. If the present is the key to the past we posit that "black" color oceans could have existed during the Proterozoic "Canfield sulfidic ocean" followed by "milky to turquoise" colored oceans during later stages of the Proterozoic. Meso-scale examples of "milky" and "turquoise" portions of oceans, caused by elemental sulfur from oxidized hydrogen sulfide eruptions, have been described from off Namibia and there appear to also exist elsewhere. Examples of "black" oceans have apparently not been reported but the name of the Black Sea, the largest

  4. Flow of Planets, Not Weak Tidal Evolution, Produces the Short-Period Planet Distribution with More Planets than Expected

    NASA Astrophysics Data System (ADS)

    Taylor, Stuart F.

    2013-01-01

    The most unexpected planet finding is arguably the number of those with shorter periods than theorists had expected, because most such close planets had been expected to migrate into the star in shorter timescales than the ages of the stars. Subsequent effort has been made to show how tidal dissipation in stars due to planets could be weaker than expected, but we show how the occurrence distribution of differently-sized planets is more consistent with the explanation that these planets have more recently arrived as a flow of inwardly migrating planets, with giant planets more likely to be found while gradually going through a short period stage. This continual ``flow'' of new planets arriving from further out is presumably supplied by the flow likely responsible for the short period pileup of giant planets (Socrates+ 2011). We have previously shown that the shortest period region of the exoplanet occurrence distribution has a fall-off shaped by inward tidal migration due to stellar tides, that is, tides on the star caused by the planets (Taylor 2011, 2012). The power index of the fall-off of giant and intermediate radius planet candidates found from Kepler data (Howard+ 2011) is close to the index of 13/3 which is expected for planets in circular orbits undergoing tidal migration. However, there is a discrepancy of the strength of the tidal migration determined using fits to the giant and medium planets distributions. This discrepancy is best resolved by the explanation that more giant than medium radii planets migrate through these short period orbits. We also present a correlation between higher eccentricity of planetary orbits with higher Fe/H of host stars, which could be explained by high eccentricity planets being associated with recent episodes of other planets into stars. By the time these planets migrate to become hot Jupiters, the pollution may be mixed into the star. The clearing of other planets by migrating hot giant planets may result in hot Jupiters

  5. Model Atmospheres and Transit Spectra for Hot Rocky Planets

    NASA Astrophysics Data System (ADS)

    Lupu, Roxana

    We propose to build a versatile set of self-consistent atmospheric models for hot rocky exoplanets and use them to predict their transit and eclipse spectra. Hot rocky exoplanets will form the majority of small planets in close-in orbits to be discovered by the TESS and Kepler K2 missions, and offer the best opportunity for characterization with current and future instruments. We will use fully non-grey radiative-convective atmospheric structure codes with cloud formation and vertical mixing, combined with a self-consistent treatment of gas chemistry above the magma ocean. Being in equilibrium with the surface, the vaporized rock material can be a good tracer of the bulk composition of the planet. We will derive the atmospheric structure and escape rates considering both volatile-free and volatile bearing compositions, which reflect the diversity of hot rocky planet atmospheres. Our models will inform follow- up observations with JWST and ground-based instruments, aid the interpretation of transit and eclipse spectra, and provide a better understanding of volatile loss in these atmospheres. Such results will help refine our picture of rocky planet formation and evolution. Planets in ultra-short period (USP) orbits are a special class of hot rocky exoplanets. As shown by Kepler, these planets are generally smaller than 2 Earth radii, suggesting that they are likely to be rocky and could have lost their volatiles through photo-evaporation. Being close to their host stars, these planets are ultra-hot, with estimated temperatures of 1000-3000 K. A number of USP planets have been already discovered (e.g. Kepler-78 b, CoRoT-7 b, Kepler-10 b), and this number is expected to grow by confirming additional planet candidates. The characterization of planets on ultra-short orbits is advantageous due to the larger number of observable transits, and the larger transit signal in the case of an evaporating atmosphere. Much advance has been made in understanding and characterizing

  6. Search for Terrestrial Planets with SIM Planet Quest

    NASA Technical Reports Server (NTRS)

    Shao, Michael; Tanner, Angelle M.; Catanzarite, Joseph H.

    2006-01-01

    SIM is an astrometric mission that will be capable of 1 microarcsec relative astrometric accuracy in a single measurement of approx.1000 sec. The search for terrestrial planets in the habitable zone around nearby stars is one of the main science goals of the project. In 2001, NASA through the peer review process selected 10 key projects, two of which had as its goal, the search for terrestrial planets around nearby stars. The two teams, one led by G. Marcy (UC Berkeley) and one lead by M. Shao (JPL), have an extensive preparatory science program underway. This paper describes the status of this activity as well as the technology status of SIM's narrow angle astrometry capability, to reach 1 uas in a single epoch measure and its ability to average multiple epoch measurements to well below 1 uas.

  7. The Earth: A Changing Planet

    NASA Astrophysics Data System (ADS)

    Ribas, Núria; Màrquez, Conxita

    2013-04-01

    text: We describe a didactic unit that rises from our own living impression about our experience on the planet. Most of us feel the Earth to be a very static place. Rocks don't easily move and most landscapes always look the same over time. Anyone would say (the same way most scientists believed until the beginning of the last century) that our planet has always remained unchanged, never transformed. But then, all of a sudden, as a misfortune for so many humans, natural hazards appear on the scene: an earthquake causing so many disasters, a tsunami carrying away everything in its path, an eruption that can destroy huge surrounding areas but also bring new geographical relief. Science cannot remain oblivious to these events, we must wonder beyond. What does an earthquake mean? Why does it happen? What about an eruption? If it comes from the inside, what can we guess from it? Researching about all of these events, scientists have been able to arrive to some important knowledge of the planet itself: It has been possible to theorize about Earth's interior. It has also been confirmed that the planet has not always been the quiet and stable place we once thought. Continents, as Wegener supposed, do move about and the Tectonic Plates Theory, thanks to the information obtained through earthquakes and eruption, can provide some interesting explanations. But how do we know about our planet's past? How can we prove that the Earth has always been moving and that its surface changes? The Earth's rocks yield the answer. Rocks have been the only witnesses throughout millions of years, since the planet first came to existence. Let's learn how to read them… Shouldn't we realize that rocks are to Geology what books are to History? This discursive process has been distributed in four learning sequences: 1. Land is not as solid nor firm as it would seem, 2. The Earth planet: a puzzle, 3. The rocks also recycle , 4. Field trip to "Sant Miquel del Fai". The subjects take about 30

  8. Biogeochemical Transformations in the History of the Ocean.

    PubMed

    Lenton, Timothy M; Daines, Stuart J

    2017-01-03

    The ocean has undergone several profound biogeochemical transformations in its 4-billion-year history, and these were an integral part of the coevolution of life and the planet. This review focuses on changes in ocean redox state as controlled by changes in biological activity, nutrient concentrations, and atmospheric O2. Motivated by disparate interpretations of available geochemical data, we aim to show how quantitative modeling-spanning microbial mats, shelf seas, and the open ocean-can help constrain past ocean biogeochemical redox states and show what caused transformations between them. We outline key controls on ocean redox structure and review pertinent proxies and their interpretation. We then apply this quantitative framework to three key questions: How did the origin of oxygenic photosynthesis transform ocean biogeochemistry? How did the Great Oxidation transform ocean biogeochemistry? And how was ocean biogeochemistry transformed in the Neoproterozoic-Paleozoic?

  9. Formation of terrestrial planets in eccentric and inclined giant-planet systems

    NASA Astrophysics Data System (ADS)

    Sotiriadis, Sotiris; Libert, Anne-Sophie; Raymond, Sean

    2016-10-01

    The orbits of extrasolar planets are more various than the circular and coplanar ones of the Solar system. We study the impact of inclined and eccentric massive giant planets on the terrestrial planet formation process. The physical and orbital parameters of the giant planets considered in this study arise from n-body simulations of three giant planets in the late stage of the gas disc, under the combined action of Type II migration and planet-planet scattering. At the dispersal of the gas disc, the two- and three-planet systems interact then with an inner disc of planetesimals and planetary embryos. We discuss the mass and orbital parameters of the terrestrial planets formed by our simulations, as well as their water content. We also investigate how the disc of planetesimals and planetary embryos modifies the eccentric and inclined orbits of the giant planets.

  10. Planet Detection Algorithms for the Terrestrial Planet Finder-C

    NASA Astrophysics Data System (ADS)

    Kasdin, N. J.; Braems, I.

    2005-12-01

    Critical to mission planning for the terrestrial planet finder coronagraph (TPF-C) is the ability to estimate integration times for planet detection. This detection is complicated by the presence of background noise due to local and exo-zodiacal dust, by residual speckle due optical errors, and by the dependence of the PSF shape on the specific coronagraph. In this paper we examine in detail the use of PSF fitting (matched filtering) for planet detection, derive probabilistic bounds for the signal-to-noise ratio by balancing missed detection and false alarm rates, and demonstrate that this is close to the optimal linear detection technique. We then compare to a Bayesian detection approach and show that for very low background the Bayesian method offers integration time improvements, but rapidly approaches the PSF fitting result for reasonable levels of background noise. We confirm via monte-carlo simulations. This work was supported under a grant from the Jet Propulsion Laboratory and by a fellowship from the Institut National de Recherche en Informatique et Automatique (INRIA).

  11. Global Warming: The Threat to the Planet

    NASA Astrophysics Data System (ADS)

    Hansen, James

    2007-04-01

    Paleoclimate data show that the Earth's climate is remarkably sensitive to global forcings. Positive feedbacks predominate. This allows the entire planet to be whipsawed between climate states. One feedback, the `albedo flip' property of water substance, provides a powerful trigger mechanism. A climate forcing that `flips' the albedo of a sufficient portion of an ice sheet can spark a cataclysm. Ice sheet and ocean inertia provides only moderate delay to ice sheet disintegration and a burst of added global warming. Recent greenhouse gas (GHG) emissions place the Earth perilously close to dramatic climate change that could run out of our control, with great dangers for humans and other creatures. CO2 is the largest human-made climate forcing, but CH4, O3, N2O and black carbon (BC) are important. Only intense simultaneous efforts to slow CO2 emissions and reduce non-CO2 forcings can keep climate within or near the range of the past million years. Some forcings are especially effective at high latitudes, so concerted efforts to reduce their emissions could still ``save the Arctic,'' while also having major benefits for human health, agricultural productivity, and the global environment.

  12. Alien Earth: Glint observations of a remote planet

    NASA Astrophysics Data System (ADS)

    Barry, Richard K.; Deming, L. Drake

    2011-11-01

    We give a preliminary report on a multi-wavelength study of specular reflections from the oceans and clouds of Earth. We use space-borne observations from a distance sufficient to ensure that light rays reflected from all parts of Earth are closely parallel, as they will be when studying exoplanets. We find that the glint properties of Earth in this far-field vantage point are surprising - in the sense that some of the brightest reflections are not from conventional ocean-glints, but appear to arise from cirrus cloud crystals. The Earth observations discussed here were acquired with the High Resolution Instrument (HRI) - a 0.3 m f/35 telescope on the Deep Impact (DI) spacecraft during the Extrasolar Planet Observation and Characterization (EPOCh) investigation.

  13. Lights, Camera, Action: Integrating Popular Film in the Health Classroom

    ERIC Educational Resources Information Center

    Diez, Keri S.; Pleban, Francis T.; Wood, Ralph J.

    2005-01-01

    This article discusses the benefits as well as the important considerations that should be taken into account in integrating popular films in health education classes. Use of popular films in the classroom, termed "cinema education," is becoming increasingly popular in teaching health education. As a matter of convenience, popular films are easy…

  14. A Guide to Using Popular Culture to Teach Composition.

    ERIC Educational Resources Information Center

    Smelstor, Marjorie, Ed.

    The purpose of this guide is to offer possible answers to questions concerning popular culture that teachers might have and to offer suggestions on utilizing popular culture materials that are available. Lesson plans are presented using materials from advertising, newspapers, comics, film, television, popular music, radio, popular literature,…

  15. Heterogeneity of Girls' Consensual Popularity: Academic and Interpersonal Behavioral Profiles

    ERIC Educational Resources Information Center

    de Bruyn, Eddy H.; Cillessen, Antonius H. N.

    2006-01-01

    The present study explored the heterogeneous nature of popularity by investigating subgroups of popular girls (N = 365) in their first year of secondary school (mean age = 13.05). Cluster analysis revealed the presence of five subgroups based upon sociometric popularity (i.e., those considered "likeable" by peers) and consensual popularity (i.e.,…

  16. Focus: Popular Culture, Censorship, Religion in the Schools.

    ERIC Educational Resources Information Center

    Stewart, Donald, Ed.

    1976-01-01

    This issue of "Kansas English" contains four articles related to popular culture, censorship, and religion. "Popular Culture Studies: A Complement to the Humanities" by Michael Marsden, focuses on the relationship between popular culture studies and the humanities, including English. "Popular Couture: La Vie En Blue" by Richard Martin, examines…

  17. Dark victory: cancer and popular Hollywood film.

    PubMed

    Lederer, Susan E

    2007-01-01

    This paper explores the cultural representations of cancer in popular Hollywood films released between 1930 and 1970. These cinematic treatments were not representative of the types of cancer that increasingly afflicted Americans, nor were filmmakers and studios concerned with realistic representations of the disease, its treatment, and its outcomes. As in the "epidemic entertainments" of the early twentieth century that portrayed diseases as cultural commodities, popular filmmakers selectively projected some cancers rather than others, favoring those that were less offensive and more photogenic. Although the characters became weak and died, they did so without gross transformations of their bodies. This paper argues that such representations nonetheless informed American attitudes about cancer and the role of medical research in overcoming the disease.

  18. Towards the Rosetta Stone of planet formation

    NASA Astrophysics Data System (ADS)

    Maciejewski, G.; Neuhäuser, R.; Errmann, R.; Mugrauer, M.; Adam, Ch.; Berndt, A.; Eisenbeiss, T.; Fiedler, S.; Ginski, Ch.; Hohle, M.; Kramm, U.; Marka, C.; Moualla, M.; Pribulla, T.; Raetz, St.; Roell, T.; Schmidt, T. O. B.; Seeliger, M.; Spaleniak, I.; Tetzlaff, N.; Trepl, L.

    2011-02-01

    Transiting exoplanets (TEPs) observed just ~10 Myrs after formation of their host systems may serve as the Rosetta Stone for planet formation theories. They would give strong constraints on several aspects of planet formation, e.g. time-scales (planet formation would then be possible within 10 Myrs), the radius of the planet could indicate whether planets form by gravitational collapse (being larger when young) or accretion growth (being smaller when young). We present a survey, the main goal of which is to find and then characterise TEPs in very young open clusters.

  19. Light Scattering from Exoplanet Oceans and Atmospheres

    NASA Astrophysics Data System (ADS)

    Zugger, Michael; Kasting, J. F.; Williams, D. M.; Kane, T. J.; Philbrick, C. R.

    2011-01-01

    Orbital variation in reflected starlight from exoplanets could eventually be used to detect surface oceans. Exoplanets with rough surfaces, or dominated by atmospheric Rayleigh scattering, should reach peak brightness in full phase, orbital longitude = 180deg, whereas ocean planets with transparent atmospheres should reach peak brightness in crescent phase near OL = 30deg. Application of Fresnel theory to a planet with no atmosphere covered by a calm ocean predicts a peak polarization fraction of 1 at OL = 74deg; however, our model shows that clouds, wind-driven waves, aerosols, absorption, and Rayleigh scattering in the atmosphere and within the water column, dilute the polarization fraction and shift the peak to other OLs. Observing at longer wavelengths reduces the obfuscation of the water polarization signature by Rayleigh scattering but does not mitigate the other effects. Planets with thick Rayleigh scattering atmospheres reach peak polarization near OL = 90deg, but clouds and Lambertian surface scattering dilute and shift this peak to smaller OL. A shifted Rayleigh peak might be mistaken for a water signature unless data from multiple wavelength bands are available. Our calculations suggest that polarization alone may not positively identify the presence of an ocean under an Earth-like atmosphere; however polarization adds another dimension which can be used, in combination with unpolarized orbital light curves and contrast ratios, to detect extrasolar oceans, atmospheric water aerosols, and water clouds. Additionally, the presence and direction of the polarization vector could be used to determine planet association with the star, and constrain orbit inclination. This research was funded by the NASA Astrobiology Institute, the University of Washington Virtual Planetary Laboratory, and the Penn State Astrobiology Institute. Authors M. Zugger, J. Kasting, and D. Williams are members of the Penn State Center for Exoplanets and Habitable Worlds.

  20. Fourier spectra from exoplanets with polar caps and ocean glint

    NASA Astrophysics Data System (ADS)

    Visser, P. M.; van de Bult, F. J.

    2015-07-01

    Context. The weak orbital-phase dependent reflection signal of an exoplanet contains information on the planet surface, such as the distribution of continents and oceans on terrestrial planets. This light curve is usually studied in the time domain, but because the signal from a stationary surface is (quasi)periodic, analysis of the Fourier series may provide an alternative, complementary approach. Aims: We study Fourier spectra from reflected light curves for geometrically simple configurations. Depending on its atmospheric properties, a rotating planet in the habitable zone could have circular polar ice caps. Tidally locked planets, on the other hand, may have symmetric circular oceans facing the star. These cases are interesting because the high-albedo contrast at the sharp edges of the ice-sheets and the glint from the host star in the ocean may produce recognizable light curves with orbital periodicity, which could also be interpreted in the Fourier domain. Methods: We derive a simple general expression for the Fourier coefficients of a quasiperiodic light curve in terms of the albedo map of a Lambertian planet surface. Analytic expressions for light curves and their spectra are calculated for idealized situations, and dependence of the spectral peaks on the key parameters inclination, obliquity, and cap size is studied. Results: The ice-scattering and ocean glint contributions can be separated out, because the coefficients for glint are all positive, whereas ice sheets lead to even-numbered, higher harmonics. An in-view polar cap on a planet without axial tilt only produces a single peak. The special situation of edge-on observation, which is important for planets in transit, leads to the most pronounced spectral behavior. Then the respective spectra from planets with a circumventing ocean, a circular ocean (eyeball world), polar caps, and rings, have characteristic power-law tails n-2, n-7/2, n-4, and (-1)n + 1n-2. Conclusions: Promising recently discovered

  1. The Popularity of P&P

    ERIC Educational Resources Information Center

    Ruffins, Paul

    2006-01-01

    "Principles and Practices" (P&P), a real estate pre-licensing class, is one of the most popular courses in adult education, because it can literally be the key to the dual American dreams: striking it rich and owning a home. One of the things that makes the P&P class unique is that it is taught in so many different venues. The…

  2. ORBITAL DISTRIBUTIONS OF CLOSE-IN PLANETS AND DISTANT PLANETS FORMED BY SCATTERING AND DYNAMICAL TIDES

    SciTech Connect

    Nagasawa, M.; Ida, S.

    2011-12-01

    We investigated the formation of close-in planets (hot Jupiters) by a combination of mutual scattering, Kozai effect, and tidal circularization, through N-body simulations of three gas giant planets, and compared the results with discovered close-in planets. We found that in about 350 cases out of 1200 runs ({approx}30%), the eccentricity of one of the planets is excited highly enough for tidal circularization by mutual close scatterings followed by secular effects due to outer planets, such as the Kozai mechanism, and the planet becomes a close-in planet through the damping of eccentricity and semimajor axis. The formation probability of close-in planets by such scattering is not affected significantly by the effect of the general relativity and inclusion of inertial modes in addition to fundamental modes in the tides. Detailed orbital distributions of the formed close-in planets and their counterpart distant planets in our simulations were compared with observational data. We focused on the possibility for close-in planets to retain non-negligible eccentricities ({approx}> 0.1) on timescales of {approx}10{sup 9} yr and have high inclinations, because close-in planets in eccentric or highly inclined orbits have recently been discovered. In our simulations we found that as many as 29% of the close-in planets have retrograde orbits, and the retrograde planets tend to have small eccentricities. On the other hand, eccentric close-in planets tend to have orbits of small inclinations.

  3. Habitability of planets on eccentric orbits: limits of the mean flux approximation??

    NASA Astrophysics Data System (ADS)

    Bolmont, Emeline; Libert, Anne-Sophie; Leconte, Jeremy; Selsis, Franck

    2015-07-01

    A few of the planets found in the insolation habitable zone (as defined by Kasting et al. 1993) are on eccentric orbits, such as HD 136118 b (eccentricity of ˜0.3, Wittenmyer et al. 2009). This raises the question of the potential habitability of planets that only spend a fraction of their orbit in the habitable zone. Usually for a planet of semi-major axis a and eccentricity e, the averaged flux over one orbit received by the planet is considered. This averaged flux corresponds to the flux received by a planet on a circular orbit of radius r = a(1-eˆ2)ˆ1/4. If this orbital distance is within the habitable zone, the planet is considered "habitable". However, for a hot star, for which the habitable zone is far from the star, the climate can be degraded when the planet is temporarily outside the habitable zone. The influence of the orbital eccentricity of a planet on its climate has already been studied for Earth-like conditions (same star, same rotation period), with Global Climate Models (GCM) such as in Williams & Pollard 2002 and Linsenmeier et al. 2014. Spiegel 2010 and Dressing et al. 2010 have also studied the effect of eccentricity for more diverse conditions with energy-balanced models. We performed a set of simulations using the Global Climate Model LMDz (Wordsworth et al. 2011, Forget et al. 2013, Leconte et al. 2013). We computed the climate of aqua planets receiving a mean flux equal to Earth's, around stars of luminosity ranging from 1 Lsun to 10-4 Lsun and of orbital eccentricity from 0 to 0.9. We show the limits of the mean flux approximation, depending on the previous parameters and also the thermal inertia of oceans.

  4. Cooperation and popularity in spatial games

    NASA Astrophysics Data System (ADS)

    Zhang, Hai-Feng; Jin, Zhen; Wang, Zhen

    2014-11-01

    Selection of the competition opponent is crucial for the evolution of cooperation in evolutionary games. In this work, we introduce a simple rule, incorporating individual popularity via the single parameter α, to study how the selection of the potential strategy sources influences individual behavior traits. For positive α players with high popularity will be considered more likely, while for negative α the opposite holds. Setting α equal to zero returns the frequently adopted random selection of the opponent. We find that positive α (namely, adopting the strategy from a more popular player) promotes the emergence of cooperation, which is robust against different interaction networks and game classes. The essence of this boosting effect can be attributed to the fact: increasing α accelerates the microscopic organization of cooperator clusters to resist the exploitation of defectors. Moreover, we also demonstrated that the introduction of a new mechanism alters the impact of uncertainty by strategy adoption on the evolution of cooperation. We thus present a viable method of understanding the ubiquitous cooperative behaviors in nature and hope that it will inspire further studies to resolve social dilemmas.

  5. MESSENGER: Exploring the Innermost Planet

    NASA Astrophysics Data System (ADS)

    Solomon, S. C.

    2011-12-01

    One of Earth's closest planetary neighbors, Mercury remained comparatively unexplored for the more than three decades that followed the three flybys of the innermost planet by the Mariner 10 spacecraft in 1974-75. Mariner 10 imaged 45% of Mercury's surface at about 1 km/pixel average resolution, confirmed Mercury's anomalously high bulk density and implied large fractional core size, discovered Mercury's internal magnetic field, documented that H and He are present in the planet's tenuous exosphere, and made the first exploration of Mercury's magnetosphere and solar wind environment. Ground-based astronomers later reported Na, K, and Ca in Mercury's exosphere; the presence of deposits in the floors of polar craters having radar characteristics best matched by water ice; and strong evidence from the planet's forced libration amplitude that Mercury has a fluid outer core. Spacecraft exploration of Mercury resumed with the selection for flight, under NASA's Discovery Program, of the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) mission. Launched in 2004, MESSENGER flew by the innermost planet three times in 2008-2009 en route to becoming the first spacecraft to orbit Mercury in March of this year. MESSENGER's first chemical remote sensing measurements of Mercury's surface indicate that the planet's bulk silicate fraction differs from those of the other inner planets, with a low-Fe surface composition intermediate between basalts and ultramafic rocks and best matched among terrestrial rocks by komatiites. Moreover, surface materials are richer in the volatile constituents S and K than predicted by most planetary formation models. Global image mosaics and targeted high-resolution images (to resolutions of 10 m/pixel) reveal that Mercury experienced globally extensive volcanism, including large expanses of plains emplaced as flood lavas and widespread examples of pyroclastic deposits likely emplaced during explosive eruptions of volatile

  6. Planet Nine From Outer Space

    NASA Astrophysics Data System (ADS)

    Batygin, Konstantin; Brown, Michael E.

    2016-10-01

    All known Kuiper belt objects with orbital periods longer than 4,000 years have orbits that are clustered in physical space. Statistically, the chances of such alignment being coincidental are smaller than a hundredth of a percent. In this talk, we show that the observed clustering of Kuiper belt orbits can be explained by a distant, eccentric, Neptune-like planet, whose orbit lies in approximately the same plane as those of the distant Kuiper belt objects, but whose perihelion is 180° away from the perihelia of the minor bodies. In addition to accounting for the observed grouping of orbital trajectories, the existence of such a planet naturally explains the presence of high-perihelion Sedna-like objects, as well as the known collection of high semi-major axis objects with inclinations between 60° and 150°.

  7. The pulsar planet production process

    NASA Technical Reports Server (NTRS)

    Phinney, E. S.; Hansen, B. M. S.

    1993-01-01

    Most plausible scenarios for the formation of planets around pulsars end with a disk of gas around the pulsar. The supplicant author then points to the solar system to bolster faith in the miraculous transfiguration of gas into planets. We here investigate this process of transfiguration. We derive analytic sequences of quasi-static disks which give good approximations to exact solutions of the disk diffusion equation with realistic opacity tables. These allow quick and efficient surveys of parameter space. We discuss the outward transfer of mass in accretion disks and the resulting timescale constraints, the effects of illumination by the central source on the disk and dust within it, and the effects of the widely different elemental compositions of the disks in the various scenarios, and their extensions to globular clusters. We point out where significant uncertainties exist in the appropriate grain opacities, and in the effect of illumination and winds from the neutron star.

  8. Artemis: A Stratospheric Planet Finder

    NASA Technical Reports Server (NTRS)

    Ford, H. C.; Petro, L. D.; Burrows, C.; Ftaclas, C.; Roggemann, M. C.; Trauger, J. T.

    2003-01-01

    The near-space environment of the stratosphere is far superior to terrestrial sites for optical and infrared observations. New balloon technologies will enable flights and safe recovery of 2-ton payloads at altitudes of 35 km for 100 days and longer. The combination of long flights and superb observing conditions make it possible to undertake science programs that otherwise could only be done from orbit. We propose to fly an "Ultra-Hubble" Stratospheric Telescope (UHST) equipped with a coronagraphic camera and active optics at 35 km to search for planets around 200 of the nearest stars. This ULDB mission will establish the frequency of solar-type planetary systems, and provide targets to search for earth-like planets.

  9. The Realm of Extrasolar Planets

    NASA Astrophysics Data System (ADS)

    Ferlet, Roger

    2010-10-01

    In November 1995, an article published in Nature [1] put planetary sciences not only as a new hot field in both observational and theoretical astrophysics but also as a topic with a large impact toward the layman. This article was reporting the first discovery of a planet orbiting a star beyond our Sun, namely the solar-type star 51 Pegasi. Nearly four centuries after Giordano Bruno was burnt in public in Roma partly for having intuitively claimed the plurality of worlds, we were entering the extraordinary epoch in which one of the oldest inquiries of mankind-are we alone in the Universe?-can be tackled with the scientific method, leaving aside centuries of endless speculations. To date (July 2010), almost 500 extrasolar planets are known. We shall briefly review the main detection methods, together with the big surprises which arose during these last exciting fifteen years, without being exhaustive.

  10. Planet-crossing asteroid survey

    NASA Technical Reports Server (NTRS)

    Wilder, P. D.

    1984-01-01

    The planet-crossing asteroid survey was begun in 1973 in order to study those asteroids which may intersect the orbits of the inner planets. Throughout the history of the survey, many of the various classes of asteroids were investigated. The near-Earth objects including the Apollo, Amor, and Aten families were studied in addition to asteroids whose orbits cross that of Mars, and some objects which are generally confined to the main belt. Observing was done on the 18 inch Schmidt telescope at the Palomar Mtn. Observatory. Typically, two consecutive photographs of a favorable field are taken. The exposure times of the films are usually twenty minutes and ten minutes, respectively. The telescope is guided at sidereal rate, so that asteroids will leave short trailed images. The films are then scanned for trails. By comparing the two films, the direction and approximate rate of motion of an asteroid may be determined.

  11. COROT: asteroseismology and planet finding

    NASA Astrophysics Data System (ADS)

    Baglin, A.; Auvergne, M.; Barge, P.; Buey, J.-T.; Catala, C.; Michel, E.; Weiss, W.; COROT Team

    2002-01-01

    The COROT project, developed in the framework of the CNES small satellite program with a wide European cooperation, will be launched in 2004. It is dedicated to seismology and detection of telluric planets. It will perform relative broad band photometry in visible light, during very long (150 days) observing runs in the same direction. Both programs are working simultaneously on the same region of the sky. The seismology program aims at mapping the H-R diagram and study in details approximately 50 targets brighter than 9th magnitude. Another 50 will also be observed with a lower accuracy. The exoplanet program will search for telluric planets slightly larger than the Earth, in the habitable zone and closer.

  12. Formation of Giant Planets and Brown Dwarves

    NASA Technical Reports Server (NTRS)

    Lissauer, Jack J.

    2003-01-01

    According to the prevailing core instability model, giant planets begin their growth by the accumulation of small solid bodies, as do terrestrial planets. However, unlike terrestrial planets, the growing giant planet cores become massive enough that they are able to accumulate substantial amounts of gas before the protoplanetary disk dissipates. Models predict that rocky planets should form in orbit about most stars. It is uncertain whether or not gas giant planet formation is common, because most protoplanetary disks may dissipate before solid planetary cores can grow large enough to gravitationally trap substantial quantities of gas. Ongoing theoretical modeling of accretion of giant planet atmospheres, as well as observations of protoplanetary disks, will help decide this issue. Observations of extrasolar planets around main sequence stars can only provide a lower limit on giant planet formation frequency . This is because after giant planets form, gravitational interactions with material within the protoplanetary disk may cause them to migrat inwards and be lost to the central star. The core instability model can only produce planets greater than a few jovian masses within protoplanetary disks that are more viscous than most such disks are believed to be. Thus, few brown dwarves (objects massive enough to undergo substantial deuterium fusion, estimated to occur above approximately 13 jovian masses) are likely to be formed in this manner. Most brown dwarves, as well as an unknown number of free-floating objects of planetary mass, are probably formed as are stars, by the collapse of extended gas/dust clouds into more compact objects.

  13. What Should Children Know about the Arctic Ocean?

    ERIC Educational Resources Information Center

    Stockard, James W., Jr.

    1989-01-01

    Lists essential information about the Arctic Ocean which should be taught in elementary social studies courses, and which teacher training programs should cover. Discusses popular misconceptions regarding the Arctic Ocean and factors, such as the coloration on maps and globes, which lead to these misconceptions. (LS)

  14. A THIRD GIANT PLANET ORBITING HIP 14810

    SciTech Connect

    Wright, J. T.; Fischer, D. A.; Ford, Eric B.; Veras, D.; Wang, J.; Henry, G. W.; Marcy, G. W.; Howard, A. W.; Johnson, John Asher

    2009-07-10

    We present new precision radial velocities and a three-planet Keplerian orbit fit for the V = 8.5, G5 V star HIP 14810. We began observing this star at Keck Observatory as part of the N2K Planet Search Project. Wright et al. announced the inner two planets to this system, and subsequent observations have revealed the outer planet and the proper orbital solution for the middle planet. The planets have minimum masses of 3.9, 1.3, and 0.6 M {sub Jup} and orbital periods of 6.67, 147.7, and 952 day, respectively. We have numerically integrated the family of orbital solutions consistent with the data and find that they are stable for at least 10{sup 6} yr. Our photometric search shows that the inner planet does not transit.

  15. Irregular Satellites of the Planets

    NASA Technical Reports Server (NTRS)

    Jewitt, David

    2005-01-01

    This proposal is directed towards the observational exploration of the irregular satellite systems of the planets. Primarily we use large-format CCD cameras on the world's largest telescopes, on Mauna Kea, to discover new irregular satellites and then to monitor their positions in order to ascertain their orbital characteristics. Separate observations are taken to determine the physical properties of the irregular satellites. The big picture science objective is to determine how these satellites were captures, and to use the properties of the satellites and their orbits to place constraints on early solar system (including formation) processes. Work in the first year has focussed on a major investigation of the Saturn irregular satellite system. We secured observing time on the Subaru and Gemini 8-m diameter telescopes in December 2004, January, February and March 2005 for the conduct of a deep, wide-area survey. This has resulted in the detection and orbit determination for 12 new satellites to be announced in the next week or two. Additional satellites were lost, temporarily, due to unusually poor weather conditions on Mauna Kea. These objects will be recovered and their orbits published next year. A separate survey of the Uranus irregular satellites was published (Sheppard, Jewitt and Kleyna 2005). Away from the telescope, we have discovered the amazing result that the four giant planets possess similar numbers of irregular satellites. This flies in the face of the standard gas-drag model for satellite capture, since only two of the giant planets are gas giants and the others (Uranus and Neptune) formed by a different process and in the absence of much gas. The constancy of the satellite number (each giant holds approximately 100 irregular satellites measured down to the kilometer scale) is either a coincidence, with different capture mechanisms at different planets giving by chance the same total numbers of irregular satellites, or indicates that the satellites

  16. Electrodynamics on extrasolar giant planets

    SciTech Connect

    Koskinen, T. T.; Yelle, R. V.; Lavvas, P.; Cho, J. Y-K.

    2014-11-20

    Strong ionization on close-in extrasolar giant planets (EGPs) suggests that their atmospheres may be affected by ion drag and resistive heating arising from wind-driven electrodynamics. Recent models of ion drag on these planets, however, are based on thermal ionization only and do not include the upper atmosphere above the 1 mbar level. These models are also based on simplified equations of resistive magnetohydrodynamics that are not always valid in extrasolar planet atmospheres. We show that photoionization dominates over thermal ionization over much of the dayside atmosphere above the 100 mbar level, creating an upper ionosphere dominated by ionization of H and He and a lower ionosphere dominated by ionization of metals such as Na, K, and Mg. The resulting dayside electron densities on close-in exoplanets are higher than those encountered in any planetary ionosphere of the solar system, and the conductivities are comparable to the chromosphere of the Sun. Based on these results and assumed magnetic fields, we constrain the conductivity regimes on close-in EGPs and use a generalized Ohm's law to study the basic effects of electrodynamics in their atmospheres. We find that ion drag is important above the 10 mbar level where it can also significantly alter the energy balance through resistive heating. Due to frequent collisions of the electrons and ions with the neutral atmosphere, however, ion drag is largely negligible in the lower atmosphere below the 10 mbar level for a reasonable range of planetary magnetic moments. We find that the atmospheric conductivity decreases by several orders of magnitude in the night side of tidally locked planets, leading to a potentially interesting large-scale dichotomy in electrodynamics between the day and night sides. A combined approach that relies on UV observations of the upper atmosphere, phase curve and Doppler measurements of global dynamics, and visual transit observations to probe the alkali metals can potentially be

  17. Planets, pluralism, and conceptual lineage

    NASA Astrophysics Data System (ADS)

    Brusse, Carl

    2016-02-01

    Conceptual change can occur for a variety of reasons; some more scientifically significant than others. The 2006 definition of 'planet', which saw Pluto reclassified as a dwarf planet, is an example toward the more mundane end of the scale. I argue however that this case serves as a useful example of a related phenomenon, whereby what appears to be a single kind term conceals two or more distinct concepts with independent scientific utility. I examine the historical background to this case, as a template for developing additional evidence for pluralist approaches to conceptual disputes within science and elsewhere. "I would like to note that the two speakers who have spoken so far have both done the same extremely insulting gaffe," he said. "They have used the expression 'a physical definition of a planet' - by implication, suggesting that a dynamical definition is not physics!" He said he felt he had to teach the panel "something you should know": that dynamics was indeed physics, and in fact was addressed before solid-state physics in every textbook ever written." (Boyle, 2010, p. 126)

  18. Observational biases for transiting planets

    NASA Astrophysics Data System (ADS)

    Kipping, David M.; Sandford, Emily

    2016-12-01

    Observational biases distort our view of nature, such that the patterns we see within a surveyed population of interest are often unrepresentative of the truth we seek. Transiting planets currently represent the most informative data set on the ensemble properties of exoplanets within 1 au of their star. However, the transit method is inherently biased due to both geometric and detection-driven effects. In this work, we derive the overall observational biases affecting the most basic transit parameters from first principles. By assuming a trapezoidal transit and using conditional probability, we infer the expected distribution of these terms both as a joint distribution and in a marginalized form. These general analytic results provide a baseline against which to compare trends predicted by mission-tailored injection/recovery simulations and offer a simple way to correct for observational bias. Our results explain why the observed population of transiting planets displays a non-uniform impact parameter distribution, with a bias towards near-equatorial geometries. We also find that the geometric bias towards observed planets transiting near periastron is attenuated by the longer durations which occur near apoastron. Finally, we predict that the observational bias with respect to ratio-of-radii is super-quadratic, scaling as (RP/R⋆)5/2, driven by an enhanced geometric transit probability and modestly longer durations.

  19. The Giant Planet Satellite Exospheres

    NASA Astrophysics Data System (ADS)

    McGrath, M. A.

    2014-12-01

    Exospheres are relatively common in the outer solar system among the moons of the gas giant planets. They span the range from very tenuous, surface-bounded exospheres (e.g., Rhea, Dione) to quite robust exospheres with exobase above the surface (e.g., Io, Triton), and include many intermediate cases (e.g., Europa, Ganymede, Enceladus). The exospheres of these moons exhibit an interesting variety of sources, from surface sputtering, to frost sublimation, to active plumes, and also well illustrate another common characteristic of the outer planet satellite exospheres, namely, that the primary species often exists both as a gas in atmosphere, and a condensate (frost or ice) on the surface. As described by Yelle et al. (1995) for Triton, "The interchange of matter between gas and solid phases on these bodies has profound effects on the physical state of the surface and the structure of the atmosphere." A brief overview of the exospheres of the outer planet satellites will be presented, including an inter-comparison of these satellites exospheres with each other, and with the exospheres of the Moon and Mercury.

  20. Planet 9 From Outer Space

    NASA Astrophysics Data System (ADS)

    Batygin, Konstantin

    2017-01-01

    At the outskirts of the solar system, beyond the orbit of Neptune, lies an expansive field of icy debris known as the Kuiper belt. The orbits of the individual asteroid-like bodies within the Kuiper belt trace out highly elongated elliptical paths, and require hundreds to thousands of years to complete a single revolution around the Sun. Although the majority of the Kuiper belt's dynamical structure can be understood within the framework of the known eight-planet solar system, bodies with orbital periods longer than about 4,000 years exhibit a peculiar orbital alignment that eludes explanation. What sculpts this alignment and how is it preserved? In this talk, I will argue that the observed clustering of Kuiper belt orbits can be maintained by a distant, eccentric, Neptune-like planet, whose orbit lies in approximately the same plane as those of the distant Kuiper belt objects, but is anti-aligned with respect to those of the small bodies. In addition to accounting for the observed grouping of orbits, the existence of such a planet naturally explains other, seemingly unrelated dynamical features of the solar system.

  1. Orbits and Interiors of Planets

    NASA Astrophysics Data System (ADS)

    Batygin, Konstantin

    2012-05-01

    The focus of this thesis is a collection of problems of timely interest in orbital dynamics and interior structure of planetary bodies. The first three chapters are dedicated to understanding the interior structure of close-in, gaseous extrasolar planets (hot Jupiters). In order to resolve a long-standing problem of anomalously large hot Jupiter radii, we proposed a novel magnetohydrodynamic mechanism responsible for inflation. The mechanism relies on the electro-magnetic interactions between fast atmospheric flows and the planetary magnetic field in a thermally ionized atmosphere, to induce electrical currents that flow throughout the planet. The resulting Ohmic dissipation acts to maintain the interior entropies, and by extension the radii of hot Jupiters at an enhanced level. Using self-consistent calculations of thermal evolution of hot Jupiters under Ohmic dissipation, we demonstrated a clear tendency towards inflated radii for effective temperatures that give rise to significant ionization of K and Na in the atmosphere, a trend fully consistent with the observational data. Furthermore, we found that in absence of massive cores, low-mass hot Jupiters can over-flow their Roche-lobes and evaporate on Gyr time-scales, possibly leaving behind small rocky cores. Chapters four through six focus on the improvement and implications of a model for orbital evolution of the solar system, driven by dynamical instability (termed the "Nice" model). Hydrodynamical studies of the orbital evolution of planets embedded in protoplanetary disks suggest that giant planets have a tendency to assemble into multi-resonant configurations. Following this argument, we used analytical methods as well as self-consistent numerical N-body simulations to identify fully-resonant primordial states of the outer solar system, whose dynamical evolutions give rise to orbital architectures that resemble the current solar system. We found a total of only eight such initial conditions, providing

  2. The Giant Planet Satellite Exospheres

    NASA Technical Reports Server (NTRS)

    McGrath, Melissa A.

    2014-01-01

    Exospheres are relatively common in the outer solar system among the moons of the gas giant planets. They span the range from very tenuous, surface-bounded exospheres (e.g., Rhea, Dione) to quite robust exospheres with exobase above the surface (e.g., lo, Triton), and include many intermediate cases (e.g., Europa, Ganymede, Enceladus). The exospheres of these moons exhibit an interesting variety of sources, from surface sputtering, to frost sublimation, to active plumes, and also well illustrate another common characteristic of the outer planet satellite exospheres, namely, that the primary species often exists both as a gas in atmosphere, and a condensate (frost or ice) on the surface. As described by Yelle et al. (1995) for Triton, "The interchange of matter between gas and solid phases on these bodies has profound effects on the physical state of the surface and the structure of the atmosphere." A brief overview of the exospheres of the outer planet satellites will be presented, including an inter-comparison of these satellites exospheres with each other, and with the exospheres of the Moon and Mercury.

  3. Water Cycling Between Ocean and Mantle: Super-Earths Need Not be Waterworlds

    NASA Astrophysics Data System (ADS)

    Cowan, Nicolas B.; Abbot, D. S.

    2014-01-01

    Large terrestrial planets are expected to have muted topography and deep oceans, implying they should be entirely covered in water, so-called waterworlds. Quantitatively, a planet ten times the mass of Earth is not expected to have exposed continents unless it has a water mass fraction less than 3×10-5, roughly ten times drier than Earth. This is important because waterworlds lack a silicate weathering thermostat so their climate is predicted to be less stable than that of planets with exposed continents. Water is partitioned, however, between a surface reservoir, the ocean, and an interior reservoir, the mantle. Plate tectonics transports water between these reservoirs on geological timescales. Degassing of melt at mid-ocean ridges and serpentinization of oceanic crust are mediated by sea-floor pressure, providing a stabilizing feedback on long-term ocean volume. Motivated by Earth's approximately steady-state deep water cycle, we develop a two-box model of the hydrosphere and derive steady-state solutions to the water-partitioning on terrestrial planets. Since hydrostatic pressure is proportional to gravity, super-Earths with a deep water cycle will tend to store most of their water in the mantle. We conclude that tectonically active terrestrial planets with H2O mass fractions less than 3×10-3 will have both oceans and exposed continents. The circumstellar habitable zone is therefore equally wide for any tectonically active planet.

  4. Controls on the Climates of Tidally Locked Terrestrial Planets

    NASA Astrophysics Data System (ADS)

    Yang, J.; Cowan, N. B.; Abbot, D. S.

    2013-12-01

    Earth-size planets in the habitable zone of M-dwarf stars may be very common. Due to strong tidal forces, these planets in circulate orbits are expected to be tidally locked, with one hemisphere experiencing perpetual day and the other permanent night. Previous studies on the climates of tidally locked planets were primarily based on complex 3D general circulation models (GCMs). The central question to be answered in this work is: what is the minimum necessary physics needed to understand the climates simulated by GCMs? A two-column model, primarily based on the weak temperature gradient (WTG) approximation (Sobel et al. 2001) and the fixed anvil temperature (FAT) hypothesis (Hartmann and Larson 2002) for the tropical climate of Earth, is developed for understanding the climates of tidally locked planets. This highly idealized model well reproduces fundamental features of the climates obtained in complicated GCMs (Yang et al. 2013), including planetary albedo, longwave cloud forcing, outgoing longwave radiation (OLR), and atmospheric energy transport. This suggests that the WTG approximation and the FAT hypothesis may be good approximations for tidally locked habitable planets, which provides strong constraints on the large-scale circulations, diabatic processes, and cloud behaviour on these planets. Both the simple model and the GCMs predict that (i) convection and planetary albedo on the dayside increase as stellar flux is increased; (ii) longwave cloud radiative forcing increases as stellar flux is increased, due to the cloud top temperature remains nearly constant as the climate changes (FAT hypothesis); (iii) for planets at the inner regions of the habitable zone, the dayside--nightside OLR contrast becomes very weak or even reverses, due to the strong longwave absorption by water vapor and clouds on the dayside; (iv) the dayside--to--nightside atmospheric energy transport (AET) increases as stellar flux is increased, and decreases as oceanic energy transport

  5. The Evryscope and extrasolar planets

    NASA Astrophysics Data System (ADS)

    Fors, Octavi; Law, Nicholas Michael; Ratzloff, Jeffrey; del Ser, Daniel; Wulfken, Philip J.; Kavanaugh, Dustin

    2015-08-01

    The Evryscope (Law et al. 2015) is a 24-camera hemispherical all-sky gigapixel telescope (8,000 sq.deg. FoV) with rapid cadence (2mins exposure, 4sec readout) installed at CTIO. Ground-based single-station transiting surveys typically suffer from light curve sparsity and suboptimal efficiency because of their limited field of view (FoV), resulting in incomplete and biased detections. In contrast, the Evryscope offers 97% survey efficiency and one of the single-station most continuous and simultaneous monitoring of millions of stars (only limited by the day-night window).This unique facility is capable of addressing new and more extensive planetary populations, including: 1) for the first time, continuously monitor every 2mins a set of ~1000 bright white dwarfs (WDs). This will allow us to put constraints on the habitable planet fraction of Ceres-size planetesimals at the level of 30%, only in a survey timescales of a few weeks, as well as first-time testing planetary evolution models beyond the AGB phase. 2) search for rocky planets in the habitable zone around ~5,000 bright, nearby M-dwarfs. 3) synergies between Evryscope and upcoming exoplanets missions (e.g. TESS, PLATO) are also promising for target pre-imaging characterization, and increasing the giant planet yield by recovering multiple transits from planets seen as single transit events from space. 4) all-sky 2-min cadence of rare microlensing events of nearby stars. 5) all-sky continuous survey of microlensing events of nearby stars at 2mins cadence. 6) increase the census of giant planets around ~70,000 nearby, bright (g<10) solar-type stars, whose atmospheres can be characterized by follow-up observations. We are developing new data analysis algorithms to address the above scientific goals: from detecting the extremely short and faint transits around WDs, to disentangle planetary signals from very bright stars, and to combine space-based light curves with the Evryscope's ones. We will present the first

  6. Beta Pictoris planet finally imaged?

    NASA Astrophysics Data System (ADS)

    2008-11-01

    A team of French astronomers using ESO's Very Large Telescope have discovered an object located very close to the star Beta Pictoris, and which apparently lies inside its disc. With a projected distance from the star of only 8 times the Earth-Sun distance, this object is most likely the giant planet suspected from the peculiar shape of the disc and the previously observed infall of comets onto the star. It would then be the first image of a planet that is as close to its host star as Saturn is to the Sun. Sharpening Up Jupiter ESO PR Photo 42a/08 Beta Pictoris as seen in infrared light The hot star Beta Pictoris is one of the best-known examples of stars surrounded by a dusty 'debris' disc. Debris discs are composed of dust resulting from collisions among larger bodies like planetary embryos or asteroids. They are a bigger version of the zodiacal dust in our Solar System. Its disc was the first to be imaged -- as early as 1984 -- and remains the best-studied system. Earlier observations showed a warp of the disc, a secondary inclined disc and infalling comets onto the star. "These are indirect, but tell-tale signs that strongly suggest the presence of a massive planet lying between 5 and 10 times the mean Earth-Sun distance from its host star," says team leader Anne-Marie Lagrange. "However, probing the very inner region of the disc, so close to the glowing star, is a most challenging task." In 2003, the French team used the NAOS-CONICA instrument (or NACO [1]), mounted on one of the 8.2 m Unit Telescopes of ESO's Very Large Telescope (VLT), to benefit from both the high image quality provided by the Adaptive Optics system at infrared wavelengths and the good dynamics offered by the detector, in order to study the immediate surroundings of Beta Pictoris. Recently, a member of the team re-analysed the data in a different way to seek the trace of a companion to the star. Infrared wavelengths are indeed very well suited for such searches. "For this, the real challenge

  7. Ocean Acidification

    EPA Pesticide Factsheets

    Ocean and coastal acidification is an emerging issue caused by increasing amounts of carbon dioxide being absorbed by seawater. Changing seawater chemistry impacts marine life, ecosystem services, and humans. Learn what EPA is doing and what you can do.

  8. Effects of Water Amount on the Surface Environment of Terrestrial Planets: High Pressure Ice and Carbon Cycle

    NASA Astrophysics Data System (ADS)

    Nakayama, Akifumi; Abe, Yutaka

    2015-12-01

    Terrestrial planets with several wt% of H2O in extrasolar planetary systems are theoretically predicted in the habitable zone [Raymond et al., 2004]. Such planets are expected to be covered by an ocean entirely (called as “ocean planets”). Amount of atmospheric CO2 (PCO2) is important for surface environment because CO2 is a strong greenhouse gas. PCO2 is determined by a race between degassing and sink through weathering on carbon cycle. On an ocean planet, seafloor weathering is important because continental weathering can’t work [Abbot et al., 2012]. In addition, ocean planets with large water amount may have high-pressure (HP) ice on the seafloor [Leger et al., 2004]. Since the ocean floor is covered by ice in such case, it has been thought that any weathering processes will not work and PCO2 will be extremely high. When plate tectonics works, heat flow from oceanic crust decreases with distance from the mid ocean ridge. Therefore, HP ice near the mid ocean ridge will be kept solid-liquid coexistent state at the melting point because of high heat flow. Seafloor weathering works in this region. The seafloor weathering under this condition efficiently works because weathering temperature is kept melting point regardless of surface temperature. Thus, our aim is to clarify the relationship between water amount and surface environment focusing seafloor environment. We develop a carbon cycle model considering the seafloor weathering. Our major assumptions are following; 1) Earth-sized ocean planets with various water amount, 2) Degassing rate is depended on the total amount of carbon and total carbon inventory is proportional to the surface water amount. We investigated thermal state of HP ice and determined effective weathering region where HP ice is coexistent with water, then we investigated the PCO2 in equilibrium state where degassing and regassing are balanced. As a result, forming of HP ice may cause snowball state due to high weathering rate. When solar

  9. Ocean dumping

    SciTech Connect

    Not Available

    1982-01-01

    The regulation of the dumping of materials into the ocean is reviewed. Criteria to be applied in reviewing and evaluating permit applications for the transportation and dumping of materials into the ocean are established. A definition of monitoring of dumping sites, the assessment of fees to cover permit processing costs, and a moratorium is placed on the issuance of permits for the disposal of radioactive waste are included.

  10. Exotic Earths: forming habitable worlds with giant planet migration.

    PubMed

    Raymond, Sean N; Mandell, Avi M; Sigurdsson, Steinn

    2006-09-08

    Close-in giant planets (e.g., "hot Jupiters") are thought to form far from their host stars and migrate inward, through the terrestrial planet zone, via torques with a massive gaseous disk. Here we simulate terrestrial planet growth during and after giant planet migration. Several-Earth-mass planets also form interior to the migrating jovian planet, analogous to recently discovered "hot Earths." Very-water-rich, Earth-mass planets form from surviving material outside the giant planet's orbit, often in the habitable zone and with low orbital eccentricities. More than a third of the known systems of giant planets may harbor Earth-like planets.

  11. Searching for Earth-like planets in this solar system and beyond

    NASA Astrophysics Data System (ADS)

    Stofan, E. R.

    2014-12-01

    Earth sits in a narrow habitable zone, and its future habitability depends on the actions of those who inhabit the planet today. Earth's complex climate reflects interactions between its interior, surface, oceans, biosphere, atmosphere and its star - our sun. Studying the climates of other planets around our sun - Mars, Venus and Titan - can help us better understand the processes that control climate here on Earth. These three bodies provide compelling targets for future study as we explore beyond our solar system to find Earth-like worlds around other stars.

  12. Formation and survival of water vapor in the terrestrial planet-forming region.

    PubMed

    Bethell, Thomas; Bergin, Edwin

    2009-12-18

    Recent astronomical observations have revealed what may prove to be the ubiquity of water vapor during the early stages of planet formation. We present here a simple mechanism showing how water vapor forms in situ and is capable of shielding itself from molecule-destroying stellar radiation. The absorption of this radiation by water can control the thermodynamics of the terrestrial planet-forming zone. Similar to Earth's ozone layer, which shelters the chemistry of life, the water layer protects other water molecules and allows for a rich organic chemistry. The total abundance of water vapor in the natal habitable zone is equal to that of several thousand oceans.

  13. Detection of Extrasolar Planets by Transit Photometry

    NASA Technical Reports Server (NTRS)

    Borucki, William; Koch, David; Webster, Larry; Dunham, Edward; Witteborn, Fred; Jenkins, Jon; Caldwell, Douglas; Showen, Robert; DeVincenzi, Donald L. (Technical Monitor)

    2000-01-01

    A knowledge of other planetary systems that includes information on the number, size, mass, and spacing of the planets around a variety of star types is needed to deepen our understanding of planetary system formation and processes that give rise to their final configurations. Recent discoveries show that many planetary systems are quite different from the solar system in that they often possess giant planets in short period orbits. The inferred evolution of these planets and their orbital characteristics imply the absence of Earth-like planets near the habitable zone. Information on the properties of the giant-inner planets is now being obtained by both the Doppler velocity and the transit photometry techniques. The combination of the two techniques provides the mass, size, and density of the planets. For the planet orbiting star HD209458, transit photometry provided the first independent confirmation and measurement of the diameter of an extrasolar planet. The observations indicate a planet 1.27 the diameter of Jupiter with 0.63 of its mass (Charbonneau et al. 1999). The results are in excellent agreement with the theory of planetary atmospheres for a planet of the indicated mass and distance from a solar-like star. The observation of the November 23, 1999 transit of that planet made by the Ames Vulcan photometer at Lick Observatory is presented. In the future, the combination of the two techniques will greatly increase the number of discoveries and the richness of the science yield. Small rocky planets at orbital distances from 0.9 to 1.2 AU are more likely to harbor life than the gas giant planets that are now being discovered. However, new technology is needed to find smaller, Earth-like planets, which are about three hundred times less massive than Jupiter-like planets. The Kepler project is a space craft mission designed to discover hundreds of Earth-size planets in and near the habitable zone around a wide variety of stars. To demonstrate that the

  14. Planets migrating into stars: Rates and Signature

    NASA Astrophysics Data System (ADS)

    Taylor, Stuart F.

    2015-01-01

    New measurements of the occurrence distribution of planets (POD) make it possible to make the first determination of the rate of planet migration into stars as a function of the strength of stellar tidal dissipation. We show how the period at which there is falloff in the POD due to planets migrating into the star can be used to calculate this rate. We show that it does not take extremely weak tidal dissipation for this rate to be low enough to be supplied by a reasonable number of planets being scattered into the lowest period region. The presence of the shortest period giant planets can be better explained by the ongoing migration of giant planets into stars. The presence of giant planets in period on the order of a day and less had prompted some to conclude that tidal dissipation in stars must necessarily be much weaker for planet mass than for binary star mass companions. However, a flow of less than one planet per thousand stars per gigayear could explain their presence without requiring as much of a difference in tidal dissipation strength in stars for planetary than for stellar mass companions. We show several new analytical expressions describing the rate of evolution of the falloff in the POD, as well as the rate of planet. The question of how strong is the tidal dissipation (the quality factor 'Q') for planet-mass companions may be answered within a few years by a measurable time shift in the transit period. We show that the distribution of remaining planet lifetimes indicates a mass-dependence of the stellar tidal dissipation. The possibility of regular merger of planets with stars has led us to find several correlations of iron abundance in stars with planet parameters, starting with the iron-eccentricity correlation (Taylor 2012, Dawson & Murray-Clay 2013). These correlations change in the presence of a stellar companion. We show that the distribution of planets of iron-rich planets is significantly different from the distribution of iron poor stars in

  15. Stability of habitable exomoons of circumbinary planets

    NASA Astrophysics Data System (ADS)

    Satyal, Suman; Haghighipour, Nader; Quarles, Billy

    2015-12-01

    Among the currently known Kepler circumbinary planets, three, namely Kepler-453b, Kepler-16b, and Kepler-47c are in the binary habitable zone (HZ). Given the large sizes of these planets, it is unlikely that they would be habitable. However, similar to the giant planets in our solar system, these planets may have large moons, which orbit their host planets while in the HZ. These exomoons, if exist, present viable candidates for habitability. As a condition for habitability, the planet-moon system has to maintain its orbital stability for long time. Usually, the empirical formula by Holeman & Wiegert (1999) is used as a measure of orbital stability in circumbinary systems. However, this formula was obtained by assuming planets to be test particles and therefore does not include possible perturbation of the planet on the binary. In this work, we present results of more realistic calculations of stability of circumbinary planets where the interactions between planets and their central binaries are taken into account. We map the region of stability, which in this case will be specific to each system, and determine the range of the orbital parameters of the moons for which their orbits will be long-term stable.

  16. Some popular versions of uninformed consent.

    PubMed

    Hutton, J L; Ashcroft, R E

    2000-01-01

    A patient's informed consent is required by the Nuremberg code, and its successors, before she can be entered into a clinical trial. However, concern has been expressed by both patients and professionals about the beneficial or detrimental effect on the patient of asking for her consent. We examine advantages and drawbacks of popular variations on consent, which might reduce the stress on patients at the point of illness. Both informed and uninformed responses to particular trials, and trials in general, are discussed. The selection by doctors of patients, to whom entry to trials will be offered, is explored. Alternative forms of consent require restrictions on patients' knowledge, personal responsibility and freedom of choice.

  17. Biogeochemical Transformations in the History of the Ocean

    NASA Astrophysics Data System (ADS)

    Lenton, Timothy M.; Daines, Stuart J.

    2017-01-01

    The ocean has undergone several profound biogeochemical transformations in its 4-billion-year history, and these were an integral part of the coevolution of life and the planet. This review focuses on changes in ocean redox state as controlled by changes in biological activity, nutrient concentrations, and atmospheric O2. Motivated by disparate interpretations of available geochemical data, we aim to show how quantitative modeling—spanning microbial mats, shelf seas, and the open ocean—can help constrain past ocean biogeochemical redox states and show what caused transformations between them. We outline key controls on ocean redox structure and review pertinent proxies and their interpretation. We then apply this quantitative framework to three key questions: How did the origin of oxygenic photosynthesis transform ocean biogeochemistry? How did the Great Oxidation transform ocean biogeochemistry? And how was ocean biogeochemistry transformed in the Neoproterozoic-Paleozoic?

  18. Habitability of planets on eccentric orbits: limits of the mean flux approximation

    NASA Astrophysics Data System (ADS)

    Bolmont, Emeline; Libert, Anne-Sophie; Leconte, Jérémy; Selsis, Franck; Turbet, Martin; Forget, François

    2016-04-01

    A few of the planets found in the insolation habitable zone (region in which a planet with an atmosphere can sustain surface liquid water, Kasting et al. 1993) are on eccentric orbits, such as GJ 667Cc (eccentricity of < 0.3, Anglada-Escude et al. 2012) or HD 16175 b (eccentricity of 0.6, Peek et al. 2009). This raises the question of the potential habitability of planets that only spend a fraction of their orbit in the habitable zone. Usually for a planet of semi-major axis a and eccentricity e, the averaged flux over one orbit received by the planet is considered. This averaged flux corresponds to the flux received by a planet on a circular orbit of radius r = a(1 -e2)1/4. If this orbital distance is within the habitable zone, the planet is said "habitable". However, for a hot star, for which the habitable zone is far from the star, the climate can be degraded when the planet is temporarily outside the habitable zone. We investigate here the limits of validity of the mean flux approximation used to assess the potential habitability of eccentric planets. For this study, we consider ocean planets in synchronized rotation and planets with a rotation period of 24 hr. We investigate the influence of the type of host star and the eccentricity of the orbit on the climate of a planet. We do so by scaling the duration of its orbital period and its apastron and periastron distance to ensure that it receives in average the same incoming flux as Earth's. We performed sets of 3D simulations using the Global Climate Model LMDz (Wordsworth et al. 2011, Forget et al. 2013, Leconte et al. 2013). The atmosphere is composed of N2, CO2 and H2O (gas, liquid, solid) in Earth-like proportions. First, we do not take into account the spectral difference between a low luminosity star and a Sun-like star. Second, the dependence of the albedo of ice and snow on the spectra of the host star is taken into account. This influences the positive ice-albedo feedback and can lead to a different

  19. Europa - The prospects for an ocean

    NASA Technical Reports Server (NTRS)

    Reynolds, R. T.; Mckay, C. P.; Kasting, J. F.; Squires, S. W.

    1988-01-01

    Tidal dissipation in the satellites of a giant planet may provide sufficient heating to maintain a liquid water ocean below a thin ice layer. In the solar system, Europa, one of the Galilean satellites of Jupiter, may have such an ocean. Both theoretical calculations and certain observations support its existence, although proof is lacking. The putative ocean would probably have temperatures, pressures, and chemistry conducive to biologic activity. However, the environment would be severely energy limited. Possible energy sources include transient transmission of sunlight through fractures in the ice and hydrothermal activity on the ocean floor. While temporary conditions could exist that are within the range of adaptation of certain terrestrial organisms, origin of life under such conditions seems unlikely. In other solar systems, however, larger satellites with more significant heat flow could provide environments that are stable over an order of aeons and in which life could perhaps evolve.

  20. EFFECTS OF DYNAMICAL EVOLUTION OF GIANT PLANETS ON SURVIVAL OF TERRESTRIAL PLANETS

    SciTech Connect

    Matsumura, Soko; Ida, Shigeru; Nagasawa, Makiko

    2013-04-20

    The orbital distributions of currently observed extrasolar giant planets allow marginally stable orbits for hypothetical, terrestrial planets. In this paper, we propose that many of these systems may not have additional planets on these ''stable'' orbits, since past dynamical instability among giant planets could have removed them. We numerically investigate the effects of early evolution of multiple giant planets on the orbital stability of the inner, sub-Neptune-like planets which are modeled as test particles, and determine their dynamically unstable region. Previous studies have shown that the majority of such test particles are ejected out of the system as a result of close encounters with giant planets. Here, we show that secular perturbations from giant planets can remove test particles at least down to 10 times smaller than their minimum pericenter distance. Our results indicate that, unless the dynamical instability among giant planets is either absent or quiet like planet-planet collisions, most test particles down to {approx}0.1 AU within the orbits of giant planets at a few AU may be gone. In fact, out of {approx}30% of survived test particles, about three quarters belong to the planet-planet collision cases. We find a good agreement between our numerical results and the secular theory, and present a semi-analytical formula which estimates the dynamically unstable region of the test particles just from the evolution of giant planets. Finally, our numerical results agree well with the observations, and also predict the existence of hot rocky planets in eccentric giant planet systems.

  1. Imbalance in the oceanic strontium budget

    NASA Astrophysics Data System (ADS)

    Davis, Amy C.; Bickle, Mike J.; Teagle, Damon A. H.

    2003-06-01

    Palmer and Edmond [Earth Planet. Sci. Lett. 92 (1989) 11-26] indicated that thermally plausible oceanic hydrothermal inputs of strontium to the oceans are not sufficient to balance the riverine input. It has recently been suggested that off-axis low-temperature hydrothermal circulation may reconcile this discrepancy [e.g. Butterfield et al., Geochim. Cosmochim. Acta 65 (2001) 4141-4153]. Strontium isotope alteration profiles are compiled for sampled in situ ocean and ophiolite crust to calculate a sustainable cumulative hydrothermal flux to the oceanic strontium budget. High-temperature circulation contributes ˜1.8×10 9 mol yr -1 of basaltic strontium to the oceans. Enhanced hydrothermal systems in arc-related spreading environments (10% of the crust) may increase this to ˜2.3×10 9 mol yr -1. It is shown that low-temperature flow cannot supply the remaining flux required to reconcile the oceanic strontium budget (˜8.7×10 9 mol yr -1) because this would require 100% exchange of seawater strontium for basaltic strontium over an 820 m section of MORB-like crust. Currently sampled in situ ocean crust is not altered to this extent. The isotopic alteration intensity of 120 Myr crust sampled in DSDP Holes 417D and 418A indicates that off-axis low-temperature flow may contribute up to ˜8×10 8 mol yr -1 of basaltic strontium (9% of that required). The ocean crust can sustain a total basaltic strontium flux of ˜3.1±0.8×10 9 mol yr -1 ( 87Sr/ 86Sr ˜0.7025) to the oceans. This is consistent with hydrothermal flux estimates, but remains less than a third of the flux required to balance the oceanic strontium budget. The ocean crust cannot support a higher hydrothermal contribution unless the average ocean crust is significantly more altered than current observation.

  2. PLANET-PLANET SCATTERING IN PLANETESIMAL DISKS. II. PREDICTIONS FOR OUTER EXTRASOLAR PLANETARY SYSTEMS

    SciTech Connect

    Raymond, Sean N.; Armitage, Philip J.; Gorelick, Noel

    2010-03-10

    We develop an idealized dynamical model to predict the typical properties of outer extrasolar planetary systems, at radii comparable to the Jupiter-to-Neptune region of the solar system. The model is based upon the hypothesis that dynamical evolution in outer planetary systems is controlled by a combination of planet-planet scattering and planetary interactions with an exterior disk of small bodies ('planetesimals'). Our results are based on 5000 long duration N-body simulations that follow the evolution of three planets from a few to 10 AU, together with a planetesimal disk containing 50 M{sub +} from 10 to 20 AU. For large planet masses (M {approx}> M{sub Sat}), the model recovers the observed eccentricity distribution of extrasolar planets. For lower-mass planets, the range of outcomes in models with disks is far greater than that which is seen in isolated planet-planet scattering. Common outcomes include strong scattering among massive planets, sudden jumps in eccentricity due to resonance crossings driven by divergent migration, and re-circularization of scattered low-mass planets in the outer disk. We present the distributions of the eccentricity and inclination that result, and discuss how they vary with planet mass and initial system architecture. In agreement with other studies, we find that the currently observed eccentricity distribution (derived primarily from planets at a {approx}< 3 AU) is consistent with isolated planet-planet scattering. We explain the observed mass dependence-which is in the opposite sense from that predicted by the simplest scattering models-as a consequence of strong correlations between planet masses in the same system. At somewhat larger radii, initial planetary mass correlations and disk effects can yield similar modest changes to the eccentricity distribution. Nonetheless, strong damping of eccentricity for low-mass planets at large radii appears to be a secure signature of the dynamical influence of disks. Radial velocity

  3. Solar Obliquity Induced by Planet Nine

    NASA Astrophysics Data System (ADS)

    Bailey, Elizabeth; Batygin, Konstantin; Brown, Michael E.

    2016-10-01

    The six-degree obliquity of the sun suggests that either an asymmetry was present in the solar system's formation environment, or an external torque has misaligned the angular momentum vectors of the sun and the planets. However, the exact origin of this obliquity remains an open question. Batygin and Brown (2016) have recently shown that the physical alignment of distant Kuiper Belt orbits can be explained by a m9 = 10-20 mEarth planet on a distant, eccentric, and inclined orbit, with an approximate perihelion distance of q9 ˜ 250 AU. Using an analytic model for secular interactions between Planet Nine and the remaining giant planets, here we show that a planet with similar parameters can naturally generate the observed obliquity as well as the specific pole position of the sun's spin axis. Thus, Planet Nine offers a testable explanation for the otherwise mysterious spin-orbit misalignment of the solar system.

  4. Solar Obliquity Induced by Planet Nine

    NASA Astrophysics Data System (ADS)

    Bailey, Elizabeth; Batygin, Konstantin; Brown, Michael E.

    2016-11-01

    The six-degree obliquity of the Sun suggests that either an asymmetry was present in the solar system’s formation environment, or an external torque has misaligned the angular momentum vectors of the Sun and the planets. However, the exact origin of this obliquity remains an open question. Batygin & Brown have recently shown that the physical alignment of distant Kuiper Belt orbits can be explained by a 5{--}20 {m}\\oplus planet on a distant, eccentric, and inclined orbit, with an approximate perihelion distance of ˜250 au. Using an analytic model for secular interactions between Planet Nine and the remaining giant planets, here, we show that a planet with similar parameters can naturally generate the observed obliquity as well as the specific pole position of the Sun’s spin axis, from a nearly aligned initial state. Thus, Planet Nine offers a testable explanation for the otherwise mysterious spin-orbit misalignment of the solar system.

  5. Volatile components and continental material of planets

    NASA Technical Reports Server (NTRS)

    Florenskiy, K. P.; Nikolayeva, O. V.

    1986-01-01

    It is shown that the continental material of the terrestrial planets varies in composition from planet to planet according to the abundances and composition of true volatiles (H20, CO2, etc.) in the outer shells of the planets. The formation of these shells occurs very early in a planet's evolution when the role of endogenous processes is indistinct and continental materials are subject to melting and vaporizing in the absence of an atmosphere. As a result, the chemical properties of continental materials are related not only to fractionation processes but also to meltability and volatility. For planets retaining a certain quantity of true volatile components, the chemical transformation of continental material is characterized by a close interaction between impact melting vaporization and endogeneous geological processes.

  6. Our Solar System Features Eight Planets

    NASA Technical Reports Server (NTRS)

    2009-01-01

    Our solar system features eight planets, seen in this artist's diagram. Although there is some debate within the science community as to whether Pluto should be classified as a Planet or a dwarf planet, the International Astronomical Union has decided on the term plutoid as a name for dwarf planets like Pluto.

    This representation is intentionally fanciful, as the planets are depicted far closer together than they really are. Similarly, the bodies' relative sizes are inaccurate. This is done for the purpose of being able to depict the solar system and still represent the bodies with some detail. (Otherwise the Sun would be a mere speck, and the planets even the majestic Jupiter would be far too small to be seen.)

  7. The SIM PlanetQuest Science Program

    NASA Technical Reports Server (NTRS)

    Edberg, Stephen J.; Traub, Wesley A.; Unwin, Stephen C.; Marr, James C., IV

    2007-01-01

    SIM PlanetQuest (hereafter, just SIM) is a NASA mission to measure the angular positions of stars with unprecedented accuracy. We outline the main astrophysical science programs planned for SIM, and related opportunities for community participation. We focus especially on SIM's ability to detect exoplanets as small as the Earth around nearby stars. The planned synergy between SIM and other planet-finding missions including Kepler and GAIA, and planet-characterizing missions including the James Webb Space Telescope (JWST), Terrestrial Planet Finder--Coronagraph (TPF-C), and Terrestrial Planet Finder--Interferometer (TPF-I), is a key element in NASA's Navigator Program to find Earth-like planets, determine their habitability, and search for signs of life in the universe. SIM's technology development is now complete and the project is proceeding towards a launch in the next decade.

  8. From Disks To Planets: A Theoretical Perspective

    NASA Astrophysics Data System (ADS)

    Bromley, Ben

    2016-07-01

    Circumstellar disks of gas and dust naturally produce planets. Observations of young stellar systems tell us the starting conditions, while planet surveys reveal an amazing diversity of outcomes. Theory tries to connect the dots with ideas on how planets emerge from dust within an evolving gas disk. Here I give a broad-brush view of planet formation from a theoretical perspective, noting recent ideas and successes. I also consider the challenges. The conversion of primordial dust into planetesimals is uncertain. Even the mass budget in solids is a problem, since the total mass in dust observed around young stars seems insufficient to account for the census of full-fledged planets. Toward resolving these issues, the Atacama Large Millimeter Array and the Karl G. Jansky Very Large Array are playing key roles in illuminating how disks become planets.

  9. Extreme water loss and abiotic O2 buildup on planets throughout the habitable zones of M dwarfs.

    PubMed

    Luger, R; Barnes, R

    2015-02-01

    We show that terrestrial planets in the habitable zones of M dwarfs older than ∼1 Gyr could have been in runaway greenhouses for several hundred million years following their formation due to the star's extended pre-main sequence phase, provided they form with abundant surface water. Such prolonged runaway greenhouses can lead to planetary evolution divergent from that of Earth. During this early runaway phase, photolysis of water vapor and hydrogen/oxygen escape to space can lead to the loss of several Earth oceans of water from planets throughout the habitable zone, regardless of whether the escape is energy-limited or diffusion-limited. We find that the amount of water lost scales with the planet mass, since the diffusion-limited hydrogen escape flux is proportional to the planet surface gravity. In addition to undergoing potential desiccation, planets with inefficient oxygen sinks at the surface may build up hundreds to thousands of bar of abiotically produced O2, resulting in potential false positives for life. The amount of O2 that builds up also scales with the planet mass; we find that O2 builds up at a constant rate that is controlled by diffusion: ∼5 bar/Myr on Earth-mass planets and up to ∼25 bar/Myr on super-Earths. As a result, some recently discovered super-Earths in the habitable zone such as GJ 667Cc could have built up as many as 2000 bar of O2 due to the loss of up to 10 Earth oceans of water. The fate of a given planet strongly depends on the extreme ultraviolet flux, the duration of the runaway regime, the initial water content, and the rate at which oxygen is absorbed by the surface. In general, we find that the initial phase of high luminosity may compromise the habitability of many terrestrial planets orbiting low-mass stars.

  10. Magnetic asymmetries of unmagnetized planets

    NASA Technical Reports Server (NTRS)

    Brecht, Stephen H.

    1990-01-01

    This letter discusses the results produced by three-dimensional hybrid particle code simulations of the solar wind interaction with unmagnetized planets such as Venus and Mars. The solar wind velocity is perpendicular to the IMF in the cases studied. It is found that there are asymmetries in both the magnetic structure and shock location for spherical obstacles ranging in radius from 1000 km to 6000 km. The asymmetries found are due to differences in the electron and ion current paths (diamagnetic behavior). Mass loading of 0(+) was not included in these simulations.

  11. Strategy for outer planets exploration

    NASA Technical Reports Server (NTRS)

    1975-01-01

    NASA's Planetary Programs Office formed a number of scientific working groups to study in depth the potential scientific return from the various candidate missions to the outer solar system. The results of these working group studies were brought together in a series of symposia to evaluate the potential outer planet missions and to discuss strategies for exploration of the outer solar system that were consistent with fiscal constraints and with anticipated spacecraft and launch vehicle capabilities. A logical, scientifically sound, and cost effective approach to exploration of the outer solar system is presented.

  12. Modeling the globally-integrated spectral variability of the Archean Earth: The purple planet

    NASA Astrophysics Data System (ADS)

    Palle, E.; Sanroma, E.; Parenteau, M. N.; Kiang, N. Y.; Gutierrez-Navarro, A. M.; Lopez, R.; Montañes-Rodríguez, P.

    2014-03-01

    Ongoing searches for exoplanetary systems have revealed a wealth of planets with diverse physical properties. Planets even smaller than the Earth have already been detected and the efforts of future missions are aimed at the discovery, and perhaps characterization, of small rocky exoplanets within the habitable zone of their stars. Clearly, what we know about our planet will be our guideline for the characterization of such planets. But the Earth has been inhabited for at least 3.8 Gyr and its appearance has changed with time. Here, we have studied the Earth during the Archean eon, 3 Gyr ago. At that time, one of the more widespread life forms on the planet were purple bacteria. These bacteria are photosynthetic microorganisms and can inhabit both aquatic and terrestrial environments. Here, we use a radiative transfer model to simulate the visible and near-infrared radiation reflected by our planet, taking into account several scenarios regarding the possible distribution of purple bacteria over continents and oceans. We find that purple bacteria have a reflectance spectrum that has a strong reflectivity increase, similar to the red edge of leafy plants, although shifted redward. This feature produces a detectable signal in the disk-averaged spectra of our planet, depending on cloud amount and bacteria concentration/ distribution. We conclude that by using multi-color photometric observations, it is possible to distinguish between an Archean Earth in which purple bacteria inhabit vast extensions of the planet and a present-day Earth with continents covered by deserts, vegetation, or microbial mats.

  13. The effect of lunarlike satellites on the orbital infrared light curves of Earth-analog planets.

    PubMed

    Moskovitz, Nicholas A; Gaidos, Eric; Williams, Darren M

    2009-04-01

    We have investigated the influence of lunarlike satellites on the infrared orbital light curves of Earth-analog extrasolar planets. Such light curves will be obtained by NASA's Terrestrial Planet Finder (TPF) and ESA's Darwin missions as a consequence of repeat observations to confirm the companion status of a putative planet and determine its orbit. We used an energy balance model to calculate disk-averaged infrared (bolometric) fluxes from planet-satellite systems over a full orbital period (one year). The satellites are assumed to lack an atmosphere, have a low thermal inertia like that of the Moon, and span a range of plausible radii. The planets are assumed to have thermal and orbital properties that mimic those of Earth, while their obliquities and orbital longitudes of inferior conjunction remain free parameters. Even if the gross thermal properties of the planet can be independently constrained (e.g., via spectroscopy or visible-wavelength detection of specular glint from a surface ocean), only the largest (approximately Mars-sized) lunarlike satellites can be detected by light curve data from a TPF-like instrument (i.e., one that achieves a photometric signal-to-noise ratio of 10 to 20 at infrared wavelengths). Nondetection of a lunarlike satellite can obfuscate the interpretation of a given system's infrared light curve so that it may resemble a single planet with high obliquity, different orbital longitude of vernal equinox relative to inferior conjunction, and in some cases drastically different thermal characteristics. If the thermal properties of the planet are not independently established, then the presence of a lunarlike satellite cannot be inferred from infrared data, which would thus demonstrate that photometric light curves alone can only be used for preliminary study, and the addition of spectroscopic data will be necessary.

  14. Minor planets: the discovery of minor satellites.

    PubMed

    Binzel, R P; VAN Flandern, T C

    1979-03-02

    The recent confirmation of the discovery of a satellite of the minor planet 532 Herculina indicates that other similar anomalous sightings are probably also due to satellites, which must therefore be numerous and commonplace. There are now 23 candidate satellites for eight minor planets, and no one of these minor planets occulting a star has failed to show evidence of at least one secondary event. Such companions are gravitationally stable but apparently have rapid tidal evolution rates.

  15. Moon and Terrestrial Planets: Unresolved Questions

    NASA Astrophysics Data System (ADS)

    Schmitt, H. H.

    2002-12-01

    . Additional unresolved questions raised by lunar exploration and study include 1) the effect of chondritic proto-cores on the timing of core formation in the terrestrial planets, 2) the number of extremely large basin-forming events (lunar diameters >2000 km) and the potential for proto-continents being formed by the differentiation of their melt sheets on water-rich planets, 3) effect of clays produced by the weathering of the debris and glass produced by pervasive asteroid and cometary impacts, 4) the many details of the differentiation of magma oceans, and 5) the processes governing the evolution of the lunar regolith. Finally, there is the question of when humans shall return to the Moon. On the one hand, the use of this unique and accessible planetary body as a scientific resource has barely begun. On the other hand, the Helium-3 fusion energy resources and deep space travel consumables that remain untapped in the lunar regolith hardly can be ignored in the face of human and environmental challenges on Earth and the species' desire to go to Mars. On both hands, it is time we took another walk on the Moon. 30 years going on 40 is long enough to think about what once was possible.

  16. Tectonics of the Outer Planet Satellites

    NASA Technical Reports Server (NTRS)

    McKinnon, W. B.; Collins, G. C.; Moore, J. M.; Nimmo, F.; Pappalardo, R. T.; Prockter, L. M.; Schenk, P. M.

    2010-01-01

    Tectonic features on the satellites of the outer planets range from the familiar, such as clearly recognizable graben on many satellites, to the bizarre, such as the ubiquitous double ridges on Europa, the twisting sets of ridges on Triton, or the isolated giant mountains rising from Io's surface. All of the large and middle-sized outer planet satellites except Io are dominated by water ice near their surfaces. Though ice is a brittle material at the cold temperatures found in the outer solar system, the amount of energy it takes to bring it close to its melting point is lower than for a rocky body. Therefore, some unique features of icy satellite tectonics may be influenced by a near-surface ductile layer beneath the brittle surface material, and several of the icy satellites may possess subsurface oceans. Sources of stress to drive tectonism are commonly dominated by the tides that deform these satellites as they orbit their primary giant planets. On several satellites, the observed tectonic features may be the result of changes in their tidal figures, or motions of their solid surfaces with respect to their tidal figures. Other driving mechanisms for tectonics include volume changes due to ice or water phase changes in the interior, thermoelastic stress, deformation of the surface above rising diapirs of warm ice, and motion of subsurface material toward large impact basins as they fill in and relax. Most satellites exhibit evidence for extensional deformation, and some exhibit strike-slip faulting, whereas contractional tectonism appears to be rare. Io s surface is unique, exhibiting huge isolated mountains that may be blocks of crust tilting and foundering into the rapidly emptying interior as the surface is constantly buried by deposits from hyperactive volcanoes. Of the satellites, diminutive Enceladus is spectacularly active; its south polar terrain is a site of young tectonism, copious heat flow, and tall plumes venting into space. Europa's surface is

  17. Searching for Planets Around other Stars

    NASA Technical Reports Server (NTRS)

    1998-01-01

    In this colloquim presentation, Professor of Astronomy, Geoffrey Marcy discusses the discovery of planets orbiting other stars. Using the Doppler shift caused by stellar wobble that is caused by nearby planetary mass, astronomers have been able to infer the existence of Jupiter-sized planets around other stars. Using a special spectrometer at Lick Observatory, the wobble of several stars have been traced over the years required to generate an accurate pattern required to infer the stellar wobble. Professor Marcy, discusses the findings of planets around 47 Ursae Majoris, 16 Cygni B, 51 Pegasus, and 56 Rho 1 Cne. In the case of 56 Rho 1 Cne the planet appears to be close to the star, within 1.5 astronomical units. The observations from the smaller Lick Observatory will be augmented by new observations from the larger telescope at the Kek observatory. This move will allow observations of smaller planets, as opposed to the massive planets thus far discovered. The astronomers also hope to observe smaller stars with the Kek data. Future spaceborne observations will allow the discovery of even smaller planets. A spaceborne interferometer is in the planning stages, and an even larger observatory, called the Terrestrial Planet Finder, is hoped for. Professor Marcy shows artists' renderings of two of the planets thus far discovered. He also briefly discusses planetary formation and shows slides of both observations from the Orion Nebula and models of stellar system formation.

  18. Ice-gas interactions during planet formation

    NASA Astrophysics Data System (ADS)

    Öberg, Karin I.

    2016-10-01

    Planets form in disks around young stars. In these disks, condensation fronts or snowlines of water, CO2, CO and other abundant molecules regulate the outcome of planet formation. Snowline locations determine how the elemental and molecular compositions of the gaseous and solid building blocks of planets evolve with distance from the central star. Snowlines may also locally increase the planet formation efficiency. Observations of snowlines have only become possible in the past couple of years. This proceeding reviews these observations as well as the theory on the physical and chemical processes in disks that affect snowline locations.

  19. THE STATISTICAL MECHANICS OF PLANET ORBITS

    SciTech Connect

    Tremaine, Scott

    2015-07-10

    The final “giant-impact” phase of terrestrial planet formation is believed to begin with a large number of planetary “embryos” on nearly circular, coplanar orbits. Mutual gravitational interactions gradually excite their eccentricities until their orbits cross and they collide and merge; through this process the number of surviving bodies declines until the system contains a small number of planets on well-separated, stable orbits. In this paper we explore a simple statistical model for the orbit distribution of planets formed by this process, based on the sheared-sheet approximation and the ansatz that the planets explore uniformly all of the stable region of phase space. The model provides analytic predictions for the distribution of eccentricities and semimajor axis differences, correlations between orbital elements of nearby planets, and the complete N-planet distribution function, in terms of a single parameter, the “dynamical temperature,” that is determined by the planetary masses. The predicted properties are generally consistent with N-body simulations of the giant-impact phase and with the distribution of semimajor axis differences in the Kepler catalog of extrasolar planets. A similar model may apply to the orbits of giant planets if these orbits are determined mainly by dynamical evolution after the planets have formed and the gas disk has disappeared.

  20. Disk's Spiral Arms Point to Possible Planets

    NASA Video Gallery

    Simulations of young stellar systems suggest that planets embedded in a circumstellar disk can produce many distinctive structures, including rings, gaps and spiral arms. This video compares comput...

  1. Planet Formation in Binary Star Systems

    NASA Astrophysics Data System (ADS)

    Martin, Rebecca

    About half of observed exoplanets are estimated to be in binary systems. Understanding planet formation and evolution in binaries is therefore essential for explaining observed exoplanet properties. Recently, we discovered that a highly misaligned circumstellar disk in a binary system can undergo global Kozai-Lidov (KL) oscillations of the disk inclination and eccentricity. These oscillations likely have a significant impact on the formation and orbital evolution of planets in binary star systems. Planet formation by core accretion cannot operate during KL oscillations of the disk. First, we propose to consider the process of disk mass transfer between the binary members. Secondly, we will investigate the possibility of planet formation by disk fragmentation. Disk self gravity can weaken or suppress the oscillations during the early disk evolution when the disk mass is relatively high for a narrow range of parameters. Thirdly, we will investigate the evolution of a planet whose orbit is initially aligned with respect to the disk, but misaligned with respect to the orbit of the binary. We will study how these processes relate to observations of star-spin and planet orbit misalignment and to observations of planets that appear to be undergoing KL oscillations. Finally, we will analyze the evolution of misaligned multi-planet systems. This theoretical work will involve a combination of analytic and numerical techniques. The aim of this research is to shed some light on the formation of planets in binary star systems and to contribute to NASA's goal of understanding of the origins of exoplanetary systems.

  2. The Fate of Unstable Circumbinary Planets

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2016-03-01

    What happens to Tattooine-like planets that are instead in unstable orbits around their binary star system? A new study examines whether such planets will crash into a host star, get ejected from the system, or become captured into orbit around one of their hosts.Orbit Around a DuoAt this point we have unambiguously detected multiple circumbinary planets, raising questions about these planets formation and evolution. Current models suggest that it is unlikely that circumbinary planets would be able to form in the perturbed environment close their host stars. Instead, its thought that the planets formed at a distance and then migrated inwards.One danger such planets face when migrating is encountering ranges of radii where their orbits become unstable. Two scientists at the University of Chicago, Adam Sutherland and Daniel Fabrycky, have studied what happens when circumbinary planets migrate into such a region and develop unstable orbits.Producing Rogue PlanetsTime for planets to either be ejected or collide with one of the two stars, as a function of the planets starting distance (in AU) from the binary barycenter. Colors represent different planetary eccentricities. [Sutherland Fabrycky 2016]Sutherland and Fabrycky used N-body simulations to determine the fates of planets orbiting around a star system consisting of two stars a primary like our Sun and a secondary roughly a tenth of its size that are separated by 1 AU.The authors find that the most common fate for a circumbinary planet with an unstable orbit is ejection from the system; over 80% of unstable planets were ejected. This has interesting implications: if the formation of circumbinary planets is common, this mechanism could be filling the Milky Way with a population of free-floating, rogue planets that no longer are associated with their host star.The next most common outcome for unstable planets is collision with one of their host stars (most often the secondary), resulting inaccretion of the planet

  3. Direct Imaging of Warm Extrasolar Planets

    SciTech Connect

    Macintosh, B

    2005-04-11

    One of the most exciting scientific discoveries in the last decade of the twentieth century was the first detection of planets orbiting a star other than our own. By now more than 130 extrasolar planets have been discovered indirectly, by observing the gravitational effects of the planet on the radial velocity of its parent star. This technique has fundamental limitations: it is most sensitive to planets close to their star, and it determines only a planet's orbital period and a lower limit on the planet's mass. As a result, all the planetary systems found so far are very different from our own--they have giant Jupiter-sized planets orbiting close to their star, where the terrestrial planets are found in our solar system. Such systems have overturned the conventional paradigm of planet formation, but have no room in them for habitable Earth-like planets. A powerful complement to radial velocity detections of extrasolar planets will be direct imaging--seeing photons from the planet itself. Such a detection would allow photometric measurements to determine the temperature and radius of a planet. Also, direct detection is most sensitive to planets in wide orbits, and hence more capable of seeing solar systems resembling our own, since a giant planet in a wide orbit does not preclude the presence of an Earth-like planet closer to the star. Direct detection, however, is extremely challenging. Jupiter is roughly a billion times fainter than our sun. Two techniques allowed us to overcome this formidable contrast and attempt to see giant planets directly. The first is adaptive optics (AO) which allows giant earth-based telescopes, such as the 10 meter W.M. Keck telescope, to partially overcome the blurring effects of atmospheric turbulence. The second is looking for young planets: by searching in the infrared for companions to young stars, we can see thermal emission from planets that are still warm with the heat of their formation. Together with a UCLA team that leads the

  4. Orbital stability of systems of closely-spaced planets, II: configurations with coorbital planets

    NASA Astrophysics Data System (ADS)

    Smith, Andrew W.; Lissauer, Jack J.

    2010-08-01

    We numerically investigate the stability of systems of 1 {M_{oplus}} planets orbiting a solar-mass star. The systems studied have either 2 or 42 planets per occupied semimajor axis, for a total of 6, 10, 126, or 210 planets, and the planets were started on coplanar, circular orbits with the semimajor axes of the innermost planets at 1 AU. For systems with two planets per occupied orbit, the longitudinal initial locations of planets on a given orbit were separated by either 60° (Trojan planets) or 180°. With 42 planets per semimajor axis, initial longitudes were uniformly spaced. The ratio of the semimajor axes of consecutive coorbital groups in each system was approximately uniform. The instability time for a system was taken to be the first time at which the orbits of two planets with different initial orbital distances crossed. Simulations spanned virtual times of up to 1 × 108, 5 × 105, and 2 × 105 years for the 6- and 10-planet, 126-planet, and 210-planet systems, respectively. Our results show that, for a given class of system (e.g., five pairs of Trojan planets orbiting in the same direction), the relationship between orbit crossing times and planetary spacing is well fit by the functional form log( t c / t 0) = b β + c, where t c is the crossing time, t 0 = 1 year, β is the separation in initial orbital semimajor axis (in terms of the mutual Hill radii of the planets), and b and c are fitting constants. The same functional form was observed in the previous studies of single planets on nested orbits (Smith and Lissauer 2009). Pairs of Trojan planets are more stable than pairs initially separated by 180°. Systems with retrograde planets (i.e., some planets orbiting in the opposite sense from others) can be packed substantially more closely than can systems with all planets orbiting in the same sense. To have the same characteristic lifetime, systems with 2 or 42 planets per orbit typically need to have about 1.5 or 2 times the orbital separation as

  5. Arctic Ocean

    NASA Technical Reports Server (NTRS)

    Parkinson, Claire L.; Zukor, Dorothy J. (Technical Monitor)

    2000-01-01

    The Arctic Ocean is the smallest of the Earth's four major oceans, covering 14x10(exp 6) sq km located entirely within the Arctic Circle (66 deg 33 min N). It is a major player in the climate of the north polar region and has a variable sea ice cover that tends to increase its sensitivity to climate change. Its temperature, salinity, and ice cover have all undergone changes in the past several decades, although it is uncertain whether these predominantly reflect long-term trends, oscillations within the system, or natural variability. Major changes include a warming and expansion of the Atlantic layer, at depths of 200-900 m, a warming of the upper ocean in the Beaufort Sea, a considerable thinning (perhaps as high as 40%) of the sea ice cover, a lesser and uneven retreat of the ice cover (averaging approximately 3% per decade), and a mixed pattern of salinity increases and decreases.

  6. Formation of the terrestrial planets

    NASA Technical Reports Server (NTRS)

    Wetherill, G. W.

    1980-01-01

    Two growth mechanisms are identified for the development of the terrestrial planets: (1) gravitational instability leading to a collapse, and (2) gravitational accumulation caused by two-body collisions and coherence. The presence of a dynamically-significant gas phase would not affect either mechanism. Theoretical expressions are presented for the production of giant gaseous protoplanets by gravitational instability within a central dust layer. Gravitational accumulation is discussed with reference to the accumulation of planetesimals from a gas-free circumsolar swarm of bodies. Numerical simulations are given for the early stages of accumulation. The Safronov steady-state velocity is considered, noting that the competition between mutual collisional damping and gravitational acceleration by the members of a solar swarm yields a steady-state velocity distribution where the mean velocity is comparable to the escape velocity of the largest body. A time scale for accumulation is postulated on the basis of the radial distribution of a swarm of non-accreting bodies of equal size. The simultaneous gas-free accumulation of several terrestrial planets is noted. Attention is also given to growth mechanisms in gas-rich interplanetary media.

  7. Perils of a Restless Planet

    NASA Astrophysics Data System (ADS)

    Zebrowski, Ernest, Jr.

    1999-05-01

    From epidemics and earthquakes to tornados and tidal waves, the overwhelming power of nature never ceases to instill humankind with both terror and awe. As natural disasters continue to claim human lives and leave destruction in their wake, Perils of a Restless Planet examines our attempts to understand and anticipate such phenomena. Now available in paperback, this highly acclaimed book draws on actual events from ancient to present times. Coverage focuses on basic scientific inquiry, technological innovation and, ultimately, public policy to provide a lucid and riveting look at the natural events that have shaped our view of natural disasters. While shedding light on the elusive quality of nature's intermittent tantrums and the limits scientific study and laboratory replication impose on our understanding of its mercurial ways, the author extrapolates from the history of science to suggest how we may someday learn to warn and protect the vulnerable populations on our small, tempestuous planet. Compelling and informative, this book will find readers both in and outside of the scientific community.

  8. Six Planets Orbiting HD 219134

    NASA Astrophysics Data System (ADS)

    Vogt, Steven S.; Burt, Jennifer; Meschiari, Stefano; Butler, R. Paul; Henry, Gregory W.; Wang, Songhu; Holden, Brad; Gapp, Cyril; Hanson, Russell; Arriagada, Pamela; Keiser, Sandy; Teske, Johanna; Laughlin, Gregory

    2015-11-01

    We present new, high-precision Doppler radial velocity (RV) data sets for the nearby K3V star HD 219134. The data include 175 velocities obtained with the HIRES Spectrograph at the Keck I Telescope and 101 velocities obtained with the Levy Spectrograph at the Automated Planet Finder Telescope at Lick Observatory. Our observations reveal six new planetary candidates, with orbital periods of P = 3.1, 6.8, 22.8, 46.7, 94.2, and 2247 days, spanning masses of {M}{sin}i=3.8, 3.5, 8.9, 21.3, 10.8, and 108 {{M}}\\oplus , respectively. Our analysis indicates that the outermost signal is unlikely to be an artifact induced by stellar activity. In addition, several years of precision photometry with the T10 0.8 m automatic photometric telescope at Fairborn Observatory demonstrated a lack of brightness variability to a limit of ∼0.0002 mag, providing strong support for planetary-reflex motion as the source of the RV variations. The HD 219134 system with its bright (V = 5.6) primary provides an excellent opportunity to obtain detailed orbital characterization (and potentially follow-up observations) of a planetary system that resembles many of the multiple-planet systems detected by Kepler, which are expected to be detected by NASA’s forthcoming TESS Mission and by ESA’s forthcoming PLATO Mission.

  9. Microlensing detection of extrasolar planets.

    PubMed

    Giannini, Emanuela; Lunine, Jonathan I

    2013-05-01

    We review the method of exoplanetary microlensing with a focus on two-body planetary lensing systems. The physical properties of planetary systems can be successfully measured by means of a deep analysis of lightcurves and high-resolution imaging of planetary systems, countering the concern that microlensing cannot determine planetary masses and orbital radii. Ground-based observers have had success in diagnosing properties of multi-planet systems from a few events, but space-based observations will be much more powerful and statistically more complete. Since microlensing is most sensitive to exoplanets beyond the snow line, whose statistics, in turn, allow for testing current planetary formation and evolution theories, we investigate the retrieval of semi-major axis density by a microlensing space-based survey with realistic parameters. Making use of a published statistical method for projected exoplanets quantities (Brown 2011), we find that one year of such a survey might distinguish between simple power-law semi-major axis densities. We conclude by briefly reviewing ground-based results hinting at a high abundance of free-floating planets and describing the potential contribution of space-based missions to understanding the frequency and mass distribution of these intriguing objects, which could help unveil the formation processes of planetary systems.

  10. Characterizing Young Giant Planets with the Gemini Planet Imager: An Iterative Approach to Planet Characterization

    NASA Technical Reports Server (NTRS)

    Marley, Mark

    2015-01-01

    After discovery, the first task of exoplanet science is characterization. However experience has shown that the limited spectral range and resolution of most directly imaged exoplanet data requires an iterative approach to spectral modeling. Simple, brown dwarf-like models, must first be tested to ascertain if they are both adequate to reproduce the available data and consistent with additional constraints, including the age of the system and available limits on the planet's mass and luminosity, if any. When agreement is lacking, progressively more complex solutions must be considered, including non-solar composition, partial cloudiness, and disequilibrium chemistry. Such additional complexity must be balanced against an understanding of the limitations of the atmospheric models themselves. For example while great strides have been made in improving the opacities of important molecules, particularly NH3 and CH4, at high temperatures, much more work is needed to understand the opacity of atomic Na and K. The highly pressure broadened fundamental band of Na and K in the optical stretches into the near-infrared, strongly influencing the spectral shape of Y and J spectral bands. Discerning gravity and atmospheric composition is difficult, if not impossible, without both good atomic opacities as well as an excellent understanding of the relevant atmospheric chemistry. I will present examples of the iterative process of directly imaged exoplanet characterization as applied to both known and potentially newly discovered exoplanets with a focus on constraints provided by GPI spectra. If a new GPI planet is lacking, as a case study I will discuss HR 8799 c and d will explain why some solutions, such as spatially inhomogeneous cloudiness, introduce their own additional layers of complexity. If spectra of new planets from GPI are available I will explain the modeling process in the context of understanding these new worlds.

  11. Planet Detection: The Kepler Mission

    NASA Astrophysics Data System (ADS)

    Jenkins, Jon M.; Smith, Jeffrey C.; Tenenbaum, Peter; Twicken, Joseph D.; Van Cleve, Jeffrey

    2012-03-01

    The search for exoplanets is one of the hottest topics in astronomy and astrophysics in the twenty-first century, capturing the public's attention as well as that of the astronomical community. This nascent field was conceived in 1989 with the discovery of a candidate planetary companion to HD114762 [35] and was born in 1995 with the discovery of the first extrasolar planet 51 Peg-b [37] orbiting a main sequence star. As of March, 2011, over 500 exoplanets have been discovered* and 106 are known to transit or cross their host star, as viewed from Earth. Of these transiting planets, 15 have been announced by the Kepler Mission, which was launched into an Earth-trailing, heliocentric orbit in March, 2009 [1,4,6,15,18,20,22,31,32,34,36,43]. In addition, over 1200 candidate transiting planets have already been detected by Kepler [5], and vigorous follow-up observations are being conducted to vet these candidates. As the false-positive rate for Kepler is expected to be quite low [39], Kepler has effectively tripled the number of known exoplanets. Moreover, Kepler will provide an unprecedented data set in terms of photometric precision, duration, contiguity, and number of stars. Kepler's primary science objective is to determine the frequency of Earth-size planets transiting their Sun-like host stars in the habitable zone, that range of orbital distances for which liquid water would pool on the surface of a terrestrial planet such as Earth, Mars, or Venus. This daunting task demands an instrument capable of measuring the light output from each of over 100,000 stars simultaneously with an unprecedented photometric precision of 20 parts per million (ppm) at 6.5-h intervals. The large number of stars is required because the probability of the geometrical alignment of planetary orbits that permit observation of transits is the ratio of the size of the star to the size of the planetary orbit. For Earth-like planets in 1-astronomical unit (AU) orbits† about sun-like stars

  12. Volatiles Inventory to the Inner Planets Due to Small Bodies Migration

    NASA Technical Reports Server (NTRS)

    Marov, M. Y.; Ipatov, S. I.

    2003-01-01

    The concurrent processes of endogeneous and exogeneous origin are assumed to be responsible for the volatile reserves in the terrestrial planets. Volatiles inventory through collisions is rooted in orbital dynamics of small bodies including near-Earth objects (NEOs), short and long-period comets, and trans-Neptunian objects (TNOs), the latter probably supplying a large amount of Jupiter crossing objects (JCOs). Our model testifies that even a relatively small portion (approx. 0.001) of JCOs which transit to orbits with aphelia inside Jupiter's orbit (Q<4.7 AU) and reside such orbits during more than 1 Myr may contribute significantly in collisions with the terrestrial planets. The total mass of volatiles delivered to the Earth from the feeding zone of the giant planets could be greater than the mass of the Earth's oceans.

  13. VizieR Online Data Catalog: Spectropolarimetric signatures of Earth--like extrasolar planets.

    NASA Astrophysics Data System (ADS)

    Stam, D. M.

    Numerically calculated scattering matrix elements a1 and b1 of 11 different types of Earth-like extrasolar planets are presented. Matrix element a1 is proportional to the total flux that is reflected by the exoplanet, matrix element b1 is proportional to the linearly polarized flux. Also given is the ratio -b1/a1, which is the degree of linear polarization of the light that is reflected by the exoplanet. Each directory contains 91 ASCII files: one file for each planetary phase angle. The phase angles range from 0 degrees ("a full planet") to 180 degrees ("a new planet"), in steps of 2 degrees. Files are labelled DDDAAN.txt, where DDD is the phase angle and AAN the model code (000fo0.txt for 0 degrees in forest0 model, 000oc0.txt for 0 degrees in ocean_0 model, 000000.txt for 0 degrees in lambert000 model). (11 data files).

  14. Inspiration Today: Music, Astronomy, and Popular Culture

    NASA Astrophysics Data System (ADS)

    Fraknoi, A.

    2016-01-01

    We explore a variety of examples of music inspired by serious astronomy (as opposed to simply an astronomical title or quick allusion to spooning in June to the light of the Moon). The examples are drawn from my recently published catalog of 133 such pieces, including both classical and popular genres of music. We discuss operas based on the life and work of astronomers, six songs based on a reasonable understanding of the properties of black holes, constellation pieces written by composers from around the world who are or were active amateur astronomers, the song that compares walking on the Moon to being in love, the little-known rock song that became a reference in the Astrophysical Journal, pieces that base the patterns of the music on the rhythms of astronomical phenomena, and a number of others.

  15. Popularity, similarity, and the network extraversion bias.

    PubMed

    Feiler, Daniel C; Kleinbaum, Adam M

    2015-05-01

    Using the emergent friendship network of an incoming cohort of students in an M.B.A. program, we examined the role of extraversion in shaping social networks. Extraversion has two important implications for the emergence of network ties: a popularity effect, in which extraverts accumulate more friends than introverts do, and a homophily effect, in which the more similar are two people's levels of extraversion, the more likely they are to become friends. These effects result in a systematic network extraversion bias, in which people's social networks will tend to be overpopulated with extraverts and underpopulated with introverts. Moreover, the most extraverted people have the greatest network extraversion bias, and the most introverted people have the least network extraversion bias. Our finding that social networks were systematically misrepresentative of the broader social environment raises questions about whether there is a societal bias toward believing other people are more extraverted than they actually are and whether introverts are better socially calibrated than extraverts.

  16. Dynamic model for the popularity of websites.

    PubMed

    Lee, Chang-Yong; Kim, Seungwhan

    2002-03-01

    In this paper, we have studied a dynamic model to explain the observed characteristics of websites in the World Wide Web. The dynamic model consists of the self-growth term for each website and the external force term acting on the website. With simulations of the model, we can explain most of the important characteristics of websites. These characteristics include a power-law distribution of the number of visitors to websites, fluctuation in the fractional growth of individual websites, and the relationship between the age and the popularity of the websites. We also investigated a few variants of the model and showed that the ingredients included in the model adequately explain the behavior of the websites.

  17. Dynamic model for the popularity of websites

    NASA Astrophysics Data System (ADS)

    Lee, Chang-Yong; Kim, Seungwhan

    2002-03-01

    In this paper, we have studied a dynamic model to explain the observed characteristics of websites in the World Wide Web. The dynamic model consists of the self-growth term for each website and the external force term acting on the website. With simulations of the model, we can explain most of the important characteristics of websites. These characteristics include a power-law distribution of the number of visitors to websites, fluctuation in the fractional growth of individual websites, and the relationship between the age and the popularity of the websites. We also investigated a few variants of the model and showed that the ingredients included in the model adequately explain the behavior of the websites.

  18. Predicting dataset popularity for the CMS experiment

    NASA Astrophysics Data System (ADS)

    Kuznetsov, V.; Li, T.; Giommi, L.; Bonacorsi, D.; Wildish, T.

    2016-10-01

    The CMS experiment at the LHC accelerator at CERN relies on its computing infrastructure to stay at the frontier of High Energy Physics, searching for new phenomena and making discoveries. Even though computing plays a significant role in physics analysis we rarely use its data to predict the system behavior itself. A basic information about computing resources, user activities and site utilization can be really useful for improving the throughput of the system and its management. In this paper, we discuss a first CMS analysis of dataset popularity based on CMS meta-data which can be used as a model for dynamic data placement and provide the foundation of data-driven approach for the CMS computing infrastructure.

  19. Welding the four most popular aluminum alloys

    SciTech Connect

    Irving, B.

    1994-02-01

    The fact that business is good in aluminum welding is a sure sign that more manufacturers and fabricators are using GMA and GTA welding to build new products out of this lightweight nonferrous metal. Among the most widely specified weldable grades are Alloys 6061, 5083, 5052 and 5454. A rundown on these four alloys, including properties and selected applications, is provided. Any company working with aluminum for the first time needs to know something about these four alloys. Alloys of copper-magnesium-silicon combination, of which 6061 is one, are heat-treatable. The three 5XXX series alloys, on the other hand, are nonheat-treatable. According to P.B. Dickerson, consultant, Lower Burrell, Pa., 5083, because of its high magnesium content, is the easiest of the four alloys to arc weld. Dickerson put the cut-off point in weldability at 3.5% magnesium. To prevent cracking, he added, both 6061 and 5052 require much more filler metal than do the other two alloys. Alloy 6061 consists of 0.25Cu, 0.6Si, 1.0Mg, and 0.20Cr. The main applications for 6061 aluminum are structural, architectural, automotive, railway, marine and pipe. It has good formability, weldability, corrosion resistance and strength. Although the 6XXX series alloys are prone to hot cracking, this condition can be readily overcome by correct choice of joint design and electrode. The most popular temper for 6061 is T6, although the -T651, -T4, and -F temper are also popular. The -T651 temper is like a -T6 temper, only it has received some final stretch hardening. The -T4 temper has been solution heat-treated and quenched. The -F temper is in the as-fabricated condition.

  20. Structure of Science Popularizations: A Genre-Analysis Approach to the Schema of Popularized Medical Texts.

    ERIC Educational Resources Information Center

    Nwogu, Kevin N.

    1991-01-01

    Attempts to characterize one discourse type of science popularization, the Journalistic Reported Version (JRV) of research articles in science magazines and newspapers. Results indicate that the JRV has an identifiable schema by which the information it contains is structured, and a typical JRV text may have as many as nine schematic structures.…

  1. Teaching Popular Music in Finland: What's Up, What's Ahead?

    ERIC Educational Resources Information Center

    Vakeva, Lauri

    2006-01-01

    This article describes the history and current situation of popular music pedagogy in Finland. While popular music is widely accepted in the curriculum, there are differences in its application in the comprehensive schools and music institutions. Popular styles were first introduced into Finnish music education by secondary school music teachers;…

  2. The Use of Popular Science Articles in Teaching Scientific Literacy

    ERIC Educational Resources Information Center

    Parkinson, Jean; Adendorff, Ralph

    2004-01-01

    This article considers the use of popular science articles in teaching scientific literacy. Comparing the discourse features of popular science with research article and textbook science--the last two being target forms for students--it argues that popular science articles cannot serve as models for scientific writing. It does, however, suggest…

  3. Academic Self-Presentation Strategies and Popularity in Middle School

    ERIC Educational Resources Information Center

    Zook, Joan M.; Russotti, Justin M.

    2013-01-01

    This study examined early adolescents' beliefs about which academic self-presentation strategies hypothetical hard-working, high-achieving students should use with popular peers, adolescents' own use of self-presentation strategies, and links between popularity and self-presentation strategies. In response to scenarios in which popular classmates…

  4. Terrestrial Planet Formation in Binary Star Systems

    NASA Technical Reports Server (NTRS)

    Lissauer, J. J.; Quintana, E. V.; Adams, F. C.; Chambers, J. E.

    2006-01-01

    Most stars reside in binary/multiple star systems; however, previous models of planet formation have studied growth of bodies orbiting an isolated single star. Disk material has been observed around one or both components of various young close binary star systems. If planets form at the right places within such disks, they can remain dynamically stable for very long times. We have simulated the late stages of growth of terrestrial planets in both circumbinary disks around 'close' binary star systems with stellar separations ($a_B$) in the range 0.05 AU $\\le a_B \\le$ 0.4 AU and binary eccentricities in the range $0 \\le e \\le 0.8$ and circumstellar disks around individual stars with binary separations of tens of AU. The initial disk of planetary embryos is the same as that used for simulating the late stages of terrestrial planet growth within our Solar System and around individual stars in the Alpha Centauri system (Quintana et al. 2002, A.J., 576, 982); giant planets analogous to Jupiter and Saturn are included if their orbits are stable. The planetary systems formed around close binaries with stellar apastron distances less than or equal to 0.2 AU with small stellar eccentricities are very similar to those formed in the Sun-Jupiter-Saturn, whereas planetary systems formed around binaries with larger maximum separations tend to be sparser, with fewer planets, especially interior to 1 AU. Likewise, when the binary periastron exceeds 10 AU, terrestrial planets can form over essentially the entire range of orbits allowed for single stars with Jupiter-like planets, although fewer terrestrial planets tend to form within high eccentricity binary systems. As the binary periastron decreases, the radial extent of the terrestrial planet systems is reduced accordingly. When the periastron is 5 AU, the formation of Earth-like planets near 1 AU is compromised.

  5. Tidal evolution of planets around brown dwarfs

    NASA Astrophysics Data System (ADS)

    Bolmont, E.; Raymond, S. N.; Leconte, J.

    2011-11-01

    Context. The tidal evolution of planets orbiting brown dwarfs (BDs) presents an interesting case study because BDs' terrestrial planet forming region is located extremely close-in. In fact, the habitable zones of BDs range from roughly 0.001 to 0.03 AU and for the lowest-mass BDs are located interior to the Roche limit. Aims: In contrast with stars, BDs spin up as they age. Thus, the corotation distance moves inward. This has important implications for the tidal evolution of planets around BDs. Methods: We used a standard equilibrium tidal model to compute the orbital evolution of a large ensemble of planet-BD systems. We tested the effect of numerous parameters such as the initial semi-major axis and eccentricity, the rotation period of the BD, the masses of both the BD and planet, and the tidal dissipation factors. Results: We find that all planets that form at or beyond the corotation distance and with initial eccentricities smaller than ~0.1 are repelled from the BD. Some planets initially interior to corotation can survive if their inward tidal evolution is slower than the BD's spin evolution, but most initially close-in planets fall onto the BD. Conclusions: We find that the most important parameter for the tidal evolution is the initial orbital distance with respect to the corotation distance. Some planets can survive in the habitable zone for Gyr timescales, although in many cases the habitable zone moves inward past the planet's orbit in just tens to hundreds of Myr. Surviving planets can have orbital periods of less than 10 days (as small as 10 h), so they could be observable by transit.

  6. The accretion of migrating giant planets

    NASA Astrophysics Data System (ADS)

    Dürmann, Christoph; Kley, Wilhelm

    2017-02-01

    Aims: Most studies concerning the growth and evolution of massive planets focus either on their accretion or their migration only. In this work we study both processes concurrently to investigate how they might mutually affect one another. Methods: We modeled a two-dimensional disk with a steady accretion flow onto the central star and embedded a Jupiter mass planet at 5.2 au. The disk is locally isothermal and viscosity is modeled using a constant α. The planet is held on a fixed orbit for a few hundred orbits to allow the disk to adapt and carve a gap. After this period, the planet is released and free to move according to the gravitational interaction with the gas disk. The mass accretion onto the planet is modeled by removing a fraction of gas from the inner Hill sphere, and the removed mass and momentum can be added to the planet. Results: Our results show that a fast migrating planet is able to accrete more gas than a slower migrating planet. Utilizing a tracer fluid we analyzed the origin of the accreted gas originating predominantly from the inner disk for a fast migrating planet. In the case of slower migration, the fraction of gas from the outer disk increases. We also found that even for very high accretion rates, in some cases gas crosses the planetary gap from the inner to the outer disk. Our simulations show that the crossing of gas changes during the migration process as the migration rate slows down. Therefore, classical type II migration where the planet migrates with the viscous drift rate and no gas crosses the gap is no general process but may only occur for special parameters and at a certain time during the orbital evolution of the planet.

  7. OBSERVATIONS OF PLANETS AND QUASI-STELLAR RADIO SOURCES AT 3 MM.

    DTIC Science & Technology

    EXTRATERRESTRIAL RADIO WAVES), (* PLANETS , STARS, VENUS( PLANET ), MARS( PLANET ), MERCURY ( PLANET ), PLANETARY ATMOSPHERES, GALAXIES, ASTROPHYSICS, TEMPERATURE, MEASUREMENT, MICROWAVE FREQUENCY, ASTRONOMY, RADIO ASTRONOMY.

  8. Water Cycling between Ocean and Mantle: Super-Earths Need Not Be Waterworlds

    NASA Astrophysics Data System (ADS)

    Cowan, Nicolas B.; Abbot, Dorian S.

    2014-01-01

    Large terrestrial planets are expected to have muted topography and deep oceans, implying that most super-Earths should be entirely covered in water, so-called waterworlds. This is important because waterworlds lack a silicate weathering thermostat so their climate is predicted to be less stable than that of planets with exposed continents. In other words, the continuously habitable zone for waterworlds is much narrower than for Earth-like planets. A planet's water is partitioned, however, between a surface reservoir, the ocean, and an interior reservoir, the mantle. Plate tectonics transports water between these reservoirs on geological timescales. Degassing of melt at mid-ocean ridges and serpentinization of oceanic crust depend negatively and positively on seafloor pressure, respectively, providing a stabilizing feedback on long-term ocean volume. Motivated by Earth's approximately steady-state deep water cycle, we develop a two-box model of the hydrosphere and derive steady-state solutions to the water partitioning on terrestrial planets. Critically, hydrostatic seafloor pressure is proportional to surface gravity, so super-Earths with a deep water cycle will tend to store more water in the mantle. We conclude that a tectonically active terrestrial planet of any mass can maintain exposed continents if its water mass fraction is less than ~0.2%, dramatically increasing the odds that super-Earths are habitable. The greatest source of uncertainty in our study is Earth's current mantle water inventory: the greater its value, the more robust planets are to inundation. Lastly, we discuss how future missions can test our hypothesis by mapping the oceans and continents of massive terrestrial planets.

  9. Water cycling between ocean and mantle: Super-earths need not be waterworlds

    SciTech Connect

    Cowan, Nicolas B.; Abbot, Dorian S.

    2014-01-20

    Large terrestrial planets are expected to have muted topography and deep oceans, implying that most super-Earths should be entirely covered in water, so-called waterworlds. This is important because waterworlds lack a silicate weathering thermostat so their climate is predicted to be less stable than that of planets with exposed continents. In other words, the continuously habitable zone for waterworlds is much narrower than for Earth-like planets. A planet's water is partitioned, however, between a surface reservoir, the ocean, and an interior reservoir, the mantle. Plate tectonics transports water between these reservoirs on geological timescales. Degassing of melt at mid-ocean ridges and serpentinization of oceanic crust depend negatively and positively on seafloor pressure, respectively, providing a stabilizing feedback on long-term ocean volume. Motivated by Earth's approximately steady-state deep water cycle, we develop a two-box model of the hydrosphere and derive steady-state solutions to the water partitioning on terrestrial planets. Critically, hydrostatic seafloor pressure is proportional to surface gravity, so super-Earths with a deep water cycle will tend to store more water in the mantle. We conclude that a tectonically active terrestrial planet of any mass can maintain exposed continents if its water mass fraction is less than ∼0.2%, dramatically increasing the odds that super-Earths are habitable. The greatest source of uncertainty in our study is Earth's current mantle water inventory: the greater its value, the more robust planets are to inundation. Lastly, we discuss how future missions can test our hypothesis by mapping the oceans and continents of massive terrestrial planets.

  10. Ocean Currents: Marine Science Activities for Grades 5-8. Teacher's Guide.

    ERIC Educational Resources Information Center

    Halversen, Catherine; Beals, Kevin; Strang, Craig

    This teacher's guide attempts to answer questions such as: What causes ocean currents? What impact do they have on Earth's environment? and How have they influenced human history? Seven innovative activities are provided in which students can gain fascinating insights into the earth as the ocean planet. Activities focus on how wind, temperature,…

  11. Water loss from terrestrial planets with CO{sub 2}-rich atmospheres

    SciTech Connect

    Wordsworth, R. D.; Pierrehumbert, R. T.

    2013-12-01

    Water photolysis and hydrogen loss from the upper atmospheres of terrestrial planets is of fundamental importance to climate evolution but remains poorly understood in general. Here we present a range of calculations we performed to study the dependence of water loss rates from terrestrial planets on a range of atmospheric and external parameters. We show that CO{sub 2} can only cause significant water loss by increasing surface temperatures over a narrow range of conditions, with cooling of the middle and upper atmosphere acting as a bottleneck on escape in other circumstances. Around G-stars, efficient loss only occurs on planets with intermediate CO{sub 2} atmospheric partial pressures (0.1-1 bar) that receive a net flux close to the critical runaway greenhouse limit. Because G-star total luminosity increases with time but X-ray and ultraviolet/ultravoilet luminosity decreases, this places strong limits on water loss for planets like Earth. In contrast, for a CO{sub 2}-rich early Venus, diffusion limits on water loss are only important if clouds caused strong cooling, implying that scenarios where the planet never had surface liquid water are indeed plausible. Around M-stars, water loss is primarily a function of orbital distance, with planets that absorb less flux than ∼270 W m{sup –2} (global mean) unlikely to lose more than one Earth ocean of H{sub 2}O over their lifetimes unless they lose all their atmospheric N{sub 2}/CO{sub 2} early on. Because of the variability of H{sub 2}O delivery during accretion, our results suggest that many 'Earth-like' exoplanets in the habitable zone may have ocean-covered surfaces, stable CO{sub 2}/H{sub 2}O-rich atmospheres, and high mean surface temperatures.

  12. The Ocean.

    ERIC Educational Resources Information Center

    Broecker, Wallace S.

    1983-01-01

    The chemistry of the ocean, whose constituents interact with those of air and land to support life and influence climate, is known to have undergone changes since the last glacial epoch. Changes in dissolved oxygen, calcium ions, phosphate, carbon dioxide, carbonate ions, and bicarbonate ions are discussed. (JN)

  13. Ocean Acidification

    ERIC Educational Resources Information Center

    Ludwig, Claudia; Orellana, Mónica V.; DeVault, Megan; Simon, Zac; Baliga, Nitin

    2015-01-01

    The curriculum module described in this article addresses the global issue of ocean acidification (OA) (Feely 2009; Figure 1). OA is a harmful consequence of excess carbon dioxide (CO[subscript 2]) in the atmosphere and poses a threat to marine life, both algae and animal. This module seeks to teach and help students master the cross-disciplinary…

  14. Ocean nutrients

    NASA Astrophysics Data System (ADS)

    Boyd, Philip W.; Hurd, Catriona L.

    Nutrients provide the chemical life-support system for phytoplankton in the ocean. Together with the carbon fixed during photosynthesis, nutrients provide the other elements, such as N and P, needed to synthesize macromolecules to build cellular constituents such as ribosomes. The makeup of these various biochemicals, such as proteins, pigments, and nucleic acids, together determine the elemental stoichiometry of an individual phytoplankton cell. The stoichiometry of different phytoplankton species or groups will vary depending on the proportions of distinct cellular machinery, such as for growth or resource acquisition, they require for their life strategies. The uptake of nutrients by phytoplankton helps to set the primary productivity, and drives the biological pump, of the global ocean. In the case of nitrogen, the supply of nutrients is categorized as either new or regenerated. The supply of new nitrogen, such as nitrate upwelled from the ocean' interior or biological nitrogen fixation, is equal to the vertical export of particular organic matter from the upper ocean on a timescale of years. Nutrients such as silica can also play a structural role in some phytoplankton groups, such as diatoms, where they are used to synthesize a siliceous frustule that offers some mechanical protection from grazers. In this chapter, we also explore nutrient uptake kinetics, patterns in nutrient distributions in space and time, the biogeochemical cycle of nitrogen, the atmospheric supply of nutrients, departures from the Redfield ratio, and whether nutrient distributions and cycling will be altered in the future

  15. Can CMB Experiments Find Planet Nine?

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2016-04-01

    Recent studies have identified signs of an unseen, distant ninth planet in our solar system. How might we find the elusive Planet Nine? A team of scientists suggests the key might be cosmology experiments.AHypothetical PlanetOrbits of six distant Kuiper-belt objects. Their clustered perihelia and orbital orientations suggest they may have been shepherded by a massive object, hypothesized to be Planet Nine. [Caltech/Robert Hurt]Early this year, a study was published that demonstrated that the clustered orbits of distant Kuiper belt objects (and several other features of our solar system) can be explained by the gravitational tug of a yet-undiscovered planet. This hypothetical Planet Nine is predicted to be a giant planet similar to Neptune or Uranus, with a mass of more than ~10 Earthmasses, currently orbiting ~700 AU away.In a recent study, a team of scientists led by Nicolas Cowan (McGill University in Canada) has estimated the blackbody emission expected from Planet Nine. The team proposes how we might be able to search for this distant body using its heat signature.Heat from an Icy WorldCowan and collaborators first estimate Planet Nines effective temperature, based on the solar flux received at ~700 AU and assuming its internal heating is similar to Uranus or Neptune. They find that Planet Nines effective temperature would likely be an icy ~3050 K, corresponding to a blackbody peak at 50100 micrometers.Search space for Planet Nine. Based on its millimeter flux and annual parallax motion, several current and future cosmology experiments may be able to detect it. Experiments resolution ranges are shown with blue boxes. [Cowan et al. 2016]How can we detect an object withemission that peaks in this range? Intriguingly, cosmology experiments monitoring the cosmic microwave background (CMB) radiation are optimized for millimeter flux. At a wavelength of 1mm, Cowan and collaborators estimate that Planet Nine would have a very detectable flux level of ~30 mJy. The

  16. PHOTOMETRIC ORBITS OF EXTRASOLAR PLANETS

    SciTech Connect

    Brown, Robert A.

    2009-09-10

    We define and analyze the photometric orbit (PhO) of an extrasolar planet observed in reflected light. In our definition, the PhO is a Keplerian entity with six parameters: semimajor axis, eccentricity, mean anomaly at some particular time, argument of periastron, inclination angle, and effective radius, which is the square root of the geometric albedo times the planetary radius. Preliminarily, we assume a Lambertian phase function. We study in detail the case of short-period giant planets (SPGPs) and observational parameters relevant to the Kepler mission: 20 ppm photometry with normal errors, 6.5 hr cadence, and three-year duration. We define a relevant 'planetary population of interest' in terms of probability distributions of the PhO parameters. We perform Monte Carlo experiments to estimate the ability to detect planets and to recover PhO parameters from light curves. We calibrate the completeness of a periodogram search technique, and find structure caused by degeneracy. We recover full orbital solutions from synthetic Kepler data sets and estimate the median errors in recovered PhO parameters. We treat in depth a case of a Jupiter body-double. For the stated assumptions, we find that Kepler should obtain orbital solutions for many of the 100-760 SPGP that Jenkins and Doyle estimate Kepler will discover. Because most or all of these discoveries will be followed up by ground-based radial velocity observations, the estimates of inclination angle from the PhO may enable the calculation of true companion masses: Kepler photometry may break the 'msin i' degeneracy. PhO observations may be difficult. There is uncertainty about how low the albedos of SPGPs actually are, about their phase functions, and about a possible noise floor due to systematic errors from instrumental and stellar sources. Nevertheless, simple detection of SPGPs in reflected light should be robust in the regime of Kepler photometry, and estimates of all six orbital parameters may be feasible in

  17. The Abundance of Atmospheric CO2 in Ocean Exoplanets: a Novel CO2 Deposition Mechanism

    NASA Astrophysics Data System (ADS)

    Levi, A.; Sasselov, D.; Podolak, M.

    2017-03-01

    We consider super-Earth sized planets which have a water mass fraction large enough to form an external mantle composed of high-pressure water-ice polymorphs and also lack a substantial H/He atmosphere. We consider such planets in their habitable zone, so that their outermost condensed mantle is a global, deep, liquid ocean. For these ocean planets, we investigate potential internal reservoirs of CO2, the amount of CO2 dissolved in the ocean for the various saturation conditions encountered, and the ocean-atmosphere exchange flux of CO2. We find that, in a steady state, the abundance of CO2 in the atmosphere has two possible states. When wind-driven circulation is the dominant CO2 exchange mechanism, an atmosphere of tens of bars of CO2 results, where the exact value depends on the subtropical ocean surface temperature and the deep ocean temperature. When sea-ice formation, acting on these planets as a CO2 deposition mechanism, is the dominant exchange mechanism, an atmosphere of a few bars of CO2 is established. The exact value depends on the subpolar surface temperature. Our results suggest the possibility of a negative feedback mechanism, unique to water planets, where a reduction in the subpolar temperature drives more CO2 into the atmosphere to increase the greenhouse effect.

  18. The planets Uranus, Neptune, and Pluto (1971)

    NASA Technical Reports Server (NTRS)

    Palluconi, F. D.

    1972-01-01

    Design criteria relating to spacecraft intended to investigate the planets of Uranus, Neptune, and Pluto are presented. Assessments were made of the potential effects of environmental properties on vehicle performance. Pertinent data on the mass, radius, shape, mean density, rotational pole location, and mean orbital elements for the three planets are given in graphs and tables.

  19. Time for Gas Planets to Grow

    NASA Technical Reports Server (NTRS)

    Lissauer, Jack J.; DeVincenzi, Donald (Technical Monitor)

    2001-01-01

    Giant planets like Jupiter need a large reservoir of gas to grow to full size. New observations indicate that such planetary nurseries last twice as long as previously thought. These observations, and their implications for the abundance of Jupiter-like planets within our galaxy, are discussed herein.

  20. HSTEP - Homogeneous Studies of Transiting Extrasolar Planets

    NASA Astrophysics Data System (ADS)

    Southworth, John

    2014-04-01

    This paper presents a summary of the HSTEP project: an effort to calculate the physical properties of the known transiting extrasolar planets using a homogeneous approach. I discuss the motivation for the project, list the 83 planets which have already been studied, run through some important aspects of the methodology, and finish with a synopsis of the results.