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Sample records for meteor crater arizona

  1. Impact mechanics at Meteor Crater, Arizona

    USGS Publications Warehouse

    Shoemaker, Eugene Merle

    1959-01-01

    Meteor Crator is a bowl-shaped depression encompassed by a rim composed chiefly of debris stacked in layers of different composition. Original bedrock stratigraphy is preserved, inverted, in the debris. The debris rests on older disturbed strata, which are turned up at moderate to steep angles in the wall of the crater and are locally overturned near the contact with the debris. These features of Meteor Crater correspond closely to those of a crater produced by nuclear explosion where depth of burial of the device was about 1/5 the diameter of the resultant crater. Studies of craters formed by detonation of nuclear devices show that structures of the crater rims are sensitive to the depth of explosion scaled to the yield of the device. The structure of Meteor Crater is such as would be produced by a very strong shock originating about at the level of the present crater floor, 400 feet below the original surface. At supersonic to hypersonic velocity an impacting meteorite penetrates the ground by a complex mechanism that includes compression of the target rocks and the meteorite by shock as well as hydrodynamic flow of the compressed material under high pressure and temperature. The depth of penetration of the meteorite, before it loses its integrity as a single body, is a function primarily of the velocity and shape of the meteorite and the densities and equations of state of the meteorite and target. The intensely compressed material then becomes dispersed in a large volume of breccia formed in the expanding shock wave. An impact velocity of about 15 km/sec is consonant with the geology of Meteor Crater in light of the experimental equation of state of iron and inferred compressibility of the target rocks. The kinetic energy of the meteorite is estimated by scaling to have been from 1.4 to 1.7 megatons TNT equivalent.

  2. NMR spectroscopic examination of shocked sandstone from meteor crater, Arizona

    SciTech Connect

    Cygan, R.T.; Boslough, M.B. ); Kirkpatrick, R.J. )

    1994-07-10

    Solid state silicon-29 nuclear magnetic resonance (NMR) spectroscopy has been used to characterize the formation of high pressure silica polymorphs and amorphous material associated with the shocked Coconino Sandstone from Meteor Crater, Arizona. Five samples of the sandstone were obtained from several locations at the crater to represent a range of shock conditions associated with the hypervelocity impact of a 30 m-diameter meteorite. The NMR spectra for these powdered materials exhibit peaks assigned to quartz, coesite, stishovite, and glass. A new resonance in two of the moderately shocked samples is also observed. This resonance has been identified as a densified form of amorphous silica with silicon in tetrahedra with one hydroxyl group. Such a phase is evidence for a shock-induced reaction between quartz and steam under high pressure conditions. [copyright] 1994 American Institute of Physics

  3. NMR spectroscopic examination of shocked sandstone from Meteor Crater, Arizona

    SciTech Connect

    Cygan, R.T.; Boslough, M.B.; Kirkpatrick, R.J.

    1993-08-01

    Solid state silicon-29 nuclear magnetic resonance (NMR) spectroscopy has been used to characterize the formation of high pressure silica polymorphs and amorphous material associated with the shocked Coconino Sandstone from Meteor Crater, Arizona. Five samples of the sandstone were obtained from several locations at the crater to represent a range of shock conditions associated with the hypervelocity impact of a 30 m-diameter meteorite. The NMR spectra for these powdered materials exhibit peaks assigned to quartz, coesite, stishovite, and glass. A new resonance in two of the moderately shocked samples is also observed. This resonance has been identified as a densified form of amorphous silica with silicon in tetrahedra with one hydroxyl group. Such a phase is evidence for a shock-induced reaction between quartz and steam under high pressure conditions.

  4. Martian Meteor Crater

    NASA Technical Reports Server (NTRS)

    2004-01-01

    20 February 2004 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a fairly young meteor impact crater on Mars that is about the same size ( 1 kilometer; 0.62 miles) as the famous Meteor Crater in northern Arizona, U.S.A. Like the Arizona crater, boulders of ejected bedrock can be seen on the crater's ejecta blanket and in the crater itself. This crater is located in the Aethiopis region of Mars near 4.7oN, 224.1oW. Sunlight illuminates the scene from the lower left.

  5. Computer code simulations of the formation of Meteor Crater, Arizona - Calculations MC-1 and MC-2

    NASA Technical Reports Server (NTRS)

    Roddy, D. J.; Schuster, S. H.; Kreyenhagen, K. N.; Orphal, D. L.

    1980-01-01

    It has been widely accepted that hypervelocity impact processes play a major role in the evolution of the terrestrial planets and satellites. In connection with the development of quantitative methods for the description of impact cratering, it was found that the results provided by two-dimensional finite difference, computer codes is greatly improved when initial impact conditions can be defined and when the numerical results can be tested against field and laboratory data. In order to address this problem, a numerical code study of the formation of Meteor (Barringer) Crater, Arizona, has been undertaken. A description is presented of the major results from the first two code calculations, MC-1 and MC-2, that have been completed for Meteor Crater. Both calculations used an iron meteorite with a kinetic energy of 3.8 Megatons. Calculation MC-1 had an impact velocity of 25 km/sec and MC-2 had an impact velocity of 15 km/sec.

  6. Major Element Analysis of the Target Rocks at Meteor Crater, Arizona

    NASA Technical Reports Server (NTRS)

    See, Thomas H.; Hoerz, Friedrich; Mittlefehldt, David W.; Varley, Laura; Mertzman, Stan; Roddy, David

    2002-01-01

    We collected approximately 400 rock chips in continuous vertical profile at Meteor Crater, Arizona, representing, from bottom to top, the Coconino, Toroweap, Kaibab, and Moenkopi Formations to support ongoing compositional analyses of the impact melts and their stratigraphic source depth(s) and other studies at Meteor Crater that depend on the composition of the target rocks. These rock chips were subsequently pooled into 23 samples for compositional analysis by XRF (x ray fluorescence) methods, each sample reflecting a specific stratigraphic "subsection" approximately 5-10 in thick. We determined the modal abundance of quartz, dolomite, and calcite for the entire Kaibab Formation at vertical resolutions of 1-2 meters. The Coconino Formation composes the lower half of the crater cavity. It is an exceptionally pure sandstone. The Toroweap is only two inches thick and compositionally similar to Coconino, therefore, it is not a good compositional marker horizon. The Kaibab Formation is approximately 80 in thick. XRD (x ray diffraction) studies show that the Kaibab Formation is dominated by dolomite and quartz, albeit in highly variable proportions; calcite is a minor phase at best. The Kaibab at Meteor Crater is therefore a sandy dolomite rather than a limestone, consistent with pronounced facies changes in the Permian of SE Arizona over short vertical and horizontal distances. The Moenkopi forms the 12 in thick cap rock and has the highest Al2O3 and FeO concentrations of all target rocks. With several examples, we illustrate how this systematic compositional and modal characterization of the target ideologies may contribute to an understanding of Meteor Crater, such as the depth of its melt zone, and to impact cratering in general, such as the liberation of CO2 from shocked carbonates.

  7. Downslope-windstorm-type flows in Arizona's Meteor Crater - Initial findings from METCRAX II

    NASA Astrophysics Data System (ADS)

    Lehner, Manuela; Whiteman, C. David; Hoch, Sebastian W.; Cherukuru, Nihanth W.; Calhoun, Ronald; Adler, Bianca; Kalthoff, Norbert

    2014-05-01

    The experimental part of the Second Meteor Crater Experiment (METCRAX II) was conducted at the Barringer Meteorite Crater in northern Arizona in October 2013 to study the nocturnal development of downslope-windstorm-type flows in the crater basin. The almost circular and approximately 1.2-km wide and 170-m deep crater is located on a large and homogeneous plain, which slopes slightly upwards to the southwest. During nighttime katabatic flows develop on the plain on a regular basis under clear-sky conditions. As the southwesterly drainage flow approaches the crater, part of it flows over the approximately 40-m high crater rim and into the basin. Under certain conditions a deep wave is produced in the lee of the crater rim resulting in a downslope-windstorm-type flow and strong warm-air intrusions over the inner upstream crater sidewall. During these events increased wind speeds and turbulence are encountered over the southwest sidewall and temperatures in the southwest part of the basin can be more than 5 K higher than over the basin center. During the most pronounced events the temperature differences across the crater can extend more than 100 m above the crater rim. The field experiment was designed to measure the katabatic approach flow over the surrounding plain, the flow over the crater rim and the flow response inside the crater basin, making use of multiple in-situ and remote sensing instruments. Seven overnight Intensive Observational Periods (IOPs) were conducted during the one-month experimental period. Soundings taken in the crater basin revealed variations in strength, horizontal and vertical extent and persistence of the warm-air intrusions during the IOPs. Initial analysis suggests that subtle changes in the flow over the crater rim can produce significant changes in the flow response within the crater leading to warm-air intrusions. In addition, regular oscillations in the basin surface temperatures indicate a sloshing of the crater-floor inversion

  8. Characteristics of ejecta and alluvial deposits at Meteor Crater, Arizona and Odessa Craters, Texas: Results from ground penetrating radar

    NASA Technical Reports Server (NTRS)

    Grant, J. A.; Schultz, P. H.

    1991-01-01

    Previous ground penetrating radar (GRP) studies around 50,000 year old Meteor Crater revealed the potential for rapid, inexpensive, and non-destructive sub-surface investigations for deep reflectors (generally greater than 10 m). New GRP results are summarized focusing the shallow sub-surfaces (1-2 m) around Meteor Crater and the main crater at Odessa. The following subject areas are covered: (1) the thickness, distribution, and nature of the contact between surrounding alluvial deposits and distal ejecta; and (2) stratigraphic relationships between both the ejecta and alluvium derived from both pre and post crater drainages. These results support previous conclusions indicating limited vertical lowering (less than 1 m) of the distal ejecta at Meteor Crater and allow initial assessment of the gradational state if the Odessa craters.

  9. Age and geomorphic history of Meteor Crater, Arizona, from cosmogenic 36Cl and 14C in rock varnish

    USGS Publications Warehouse

    Phillips, F.M.; Zreda, M.G.; Smith, S.S.; Elmore, D.; Kubik, P.W.; Dorn, R.I.; Roddy, D.J.

    1991-01-01

    Using cosmogenic 36Cl buildup and rock varnish radiocarbon, we have measured the exposure age of rock surfaces at Meteor Crater, Arizona. Our 36Cl measurements on four dolomite boulders ejected from the crater by the impact yield a mean age of 49.7 ?? 0.85 ka, which is in excellent agreement with an average age of 49 ?? 3 ka obtained from thermoluminescence studies on shock-metamorphosed dolomite and quartz. These ages are supported by undetectably low 14C in the oldest rock varnish sample. ?? 1991.

  10. A seismic refraction technique used for subsurface investigations at Meteor Crater, Arizona

    NASA Technical Reports Server (NTRS)

    Ackermann, H. D.; Godson, R. H.; Watkins, J. S.

    1975-01-01

    A seismic refraction technique for interpreting the subsurface shape and velocity distribution of an anomalous surface feature such as an impact crater is described. The method requires the existence of a relatively deep refracting horizon and combines data obtained from both standard shallow refraction spreads and distant offset shots by using the deep refractor as a source of initial arrivals. Results obtained from applying the technique to Meteor crater generally agree with the known structure of the crater deduced by other investigators and provide new data on an extensive fractured zone surrounding the crater. The breccia lens is computed to extend roughly 190 m below the crater floor, about 30 m less than the value deduced from early drilling data. Rocks around the crater are fractured as distant as 900 m from the rim crest and to a depth of at least 800 m beneath the crater floor.

  11. Validating the MYSTIC three-dimensional radiative transfer model with observations from the complex topography of Arizona's Meteor Crater

    NASA Astrophysics Data System (ADS)

    Mayer, B.; Hoch, S. W.; Whiteman, C. D.

    2010-05-01

    The MYSTIC three-dimensional Monte-Carlo radiative transfer model has been extended to simulate solar and thermal irradiances with a rigorous consideration of topography. Forward as well as backward Monte Carlo simulations are possible for arbitrarily oriented surfaces and we demonstrate that the backward Monte Carlo technique is superior to the forward method for applications involving topography, by greatly reducing the computational demands. MYSTIC is used to simulate the short- and longwave radiation fields during a clear day and night in and around Arizona's Meteor Crater, a bowl-shaped, 165-m-deep basin with a diameter of 1200 m. The simulations are made over a 4 by 4 km domain using a 10-m horizontal resolution digital elevation model and meteorological input data collected during the METCRAX (Meteor Crater Experiment) field experiment in 2006. Irradiance (or radiative flux) measurements at multiple locations inside the crater are then used to evaluate the simulations. MYSTIC is shown to realistically model the complex interactions between topography and the radiative field, resolving the effects of terrain shading, terrain exposure, and longwave surface emissions. The effects of surface temperature variations and of temperature stratification within the crater atmosphere on the near-surface longwave irradiance are then evaluated with additional simulations.

  12. Validating the MYSTIC three-dimensional radiative transfer model with observations from the complex topography of Arizona's Meteor Crater

    NASA Astrophysics Data System (ADS)

    Mayer, B.; Hoch, S. W.; Whiteman, C. D.

    2010-09-01

    The MYSTIC three-dimensional Monte-Carlo radiative transfer model has been extended to simulate solar and thermal irradiances with a rigorous consideration of topography. Forward as well as backward Monte Carlo simulations are possible for arbitrarily oriented surfaces and we demonstrate that the backward Monte Carlo technique is superior to the forward method for applications involving topography, by greatly reducing the computational demands. MYSTIC is used to simulate the short- and longwave radiation fields during a clear day and night in and around Arizona's Meteor Crater, a bowl-shaped, 165-m-deep basin with a diameter of 1200 m. The simulations are made over a 4 by 4 km2 domain using a 10-m horizontal resolution digital elevation model and meteorological input data collected during the METCRAX (Meteor Crater Experiment) field experiment in 2006. Irradiance (or radiative flux) measurements at multiple locations inside the crater are then used to evaluate the simulations. MYSTIC is shown to realistically model the complex interactions between topography and the radiative field, resolving the effects of terrain shading, terrain exposure, and longwave surface emissions. The effects of surface temperature variations and of temperature stratification within the crater atmosphere on the near-surface longwave irradiance are then evaluated with additional simulations.

  13. Zhamanshin meteor crater

    NASA Technical Reports Server (NTRS)

    Florenskiy, P. V.; Dabizha, A. I.

    1987-01-01

    A historical survey and geographic, geologic and geophysical characteristics, the results of many years of study of the Zhamanshin meteor crater in the Northern Aral region, are reported. From this data the likely initial configuration and cause of formation of the crater are reconstructed. Petrographic and mineralogical analyses are given of the brecciated and remelted rocks, of the zhamanshinites and irgizite tektites in particular. The impact melting, dispersion and quenching processes resulting in tektite formation are discussed.

  14. Si-29 NMR spectroscopy of naturally-shocked quartz from Meteor Crater, Arizona: Correlation to Kieffer's classification scheme

    NASA Technical Reports Server (NTRS)

    Boslough, M. B.; Cygan, R. T.; Kirkpatrick, R. J.

    1993-01-01

    We have applied solid state Si-29 nuclear magnetic resonance (NMR) spectroscopy to five naturally-shocked Coconino Sandstone samples from Meteor Crater, Arizona, with the goal of examining possible correlations between NMR spectral characteristics and shock level. This work follows our observation of a strong correlation between the width of a Si-29 resonance and peak shock pressure for experimentally shocked quartz powders. The peak width increase is due to the shock-induced formation of amorphous silica, which increases as a function of shock pressure over the range that we studied (7.5 to 22 GPa). The Coconino Sandstone spectra are in excellent agreement with the classification scheme of Kieffer in terms of presence and approximate abundances of quartz, coesite, stishovite, and glass. We also observe a new resonance in two moderately shocked samples that we have tentatively identified with silicon in tetrahedra with one hydroxyl group in a densified form of amorphous silica.

  15. Meteor Crater, AZ

    NASA Technical Reports Server (NTRS)

    2002-01-01

    The Barringer Meteorite Crater (also known as 'Meteor Crater') is a gigantic hole in the middle of the arid sandstone of the Arizona desert. A rim of smashed and jumbled boulders, some of them the size of small houses, rises 50 m above the level of the surrounding plain. The crater itself is nearly a 1500 m wide, and 180 m deep. When Europeans first discovered the crater, the plain around it was covered with chunks of meteoritic iron - over 30 tons of it, scattered over an area 12 to 15 km in diameter. Scientists now believe that the crater was created approximately 50,000 years ago. The meteorite which made it was composed almost entirely of nickel-iron, suggesting that it may have originated in the interior of a small planet. It was 50 m across, weighed roughly 300,000 tons, and was traveling at a speed of 65,000 km per hour. This ASTER 3-D perspective view was created by draping an ASTER bands 3-2-1image over a digital elevation model from the US Geological Survey National Elevation Dataset.

    This image was acquired on May 17, 2001 by the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on NASA's Terra satellite. With its 14 spectral bands from the visible to the thermal infrared wavelength region, and its high spatial resolution of 15 to 90 meters (about 50 to 300 feet), ASTER will image Earth for the next 6 years to map and monitor the changing surface of our planet.

    ASTER is one of five Earth-observing instruments launched December 18,1999, on NASA's Terra satellite. The instrument was built by Japan's Ministry of Economy, Trade and Industry. A joint U.S./Japan science team is responsible for validation and calibration of the instrument and the data products. Dr. Anne Kahle at NASA's Jet Propulsion Laboratory, Pasadena, California, is the U.S. Science team leader; Bjorn Eng of JPL is the project manager. ASTER is the only high resolution imaging sensor on Terra. The Terra mission is part of NASA's Earth Science Enterprise, along

  16. Ground Penetrating Radar Field Studies of Lunar-Analog Geologic Settings and Processes: Barringer Meteor Crater and Northern Arizona Volcanics

    NASA Astrophysics Data System (ADS)

    Russell, P. S.; Grant, J. A.; Williams, K. K.; Bussey, B.

    2010-12-01

    Ground-Penetrating Radar (GPR) data from terrestrial analog environments can help constrain models for evolution of the lunar surface, aid in interpretation of orbital SAR data, and help predict what might be encountered in the subsurface during future, landed, scientific or engineering operations on the Moon. GPR can yield insight into the physical properties, clast-size distribution, and layering of the subsurface, granting a unique view of the processes affecting an area over geologic time. The purpose of our work is to demonstrate these capabilities at sites at which geologic processes, settings, and/or materials are similar to those that may be encountered on the moon, especially lava flows, impact-crater ejecta, and layered materials with varying properties. We present results from transects obtained at Barringer Meteor Crater, SP Volcano cinder cone, and Sunset Crater Volcano National Monument, all in northern Arizona. Transects were taken at several sites on the ejecta of Meteor Crater, all within a crater radius (~400 m) of the crater rim. Those taken across ejecta lobes or mounds reveal the subsurface contact of the ejecta upper surface and overlying, embaying sediments deposited by later alluvial, colluvial, and/or aeolian processes. Existing mine shafts and pits on the south side of the crater provide cross sections of the subsurface against which we compare adjacent GPR transects. The ‘actual’ number, size, and depth of clasts in the top 1-2 m of the subsurface are estimated from photos of the exposed cross sections. In GPR radargrams, reflections attributed to blocks in the top 2-5 m of the subsurface are counted, and their depth distribution noted. Taking GPR measurements along a transect at two frequencies (200 and 400 MHz) and to various depths, we obtain the ratio of the actual number of blocks in the subsurface to the number detectable with GPR, as well as an assessment of how GPR detections in ejecta decline with depth and depend on antenna

  17. Ejecta patterns of Meteor Crater, Arizona derived from the linear un-mixing of TIMS data and laboratory thermal emission spectra

    NASA Technical Reports Server (NTRS)

    Ramsey, Michael S.; Christensen, Philip R.

    1992-01-01

    Accurate interpretation of thermal infrared data depends upon the understanding and removal of complicating effects. These effects may include physical mixing of various mineralogies and particle sizes, atmospheric absorption and emission, surficial coatings, geometry effects, and differential surface temperatures. The focus is the examination of the linear spectral mixing of individual mineral or endmember spectra. Linear addition of spectra, for particles larger than the wavelength, allows for a straight-forward method of deconvolving the observed spectra, predicting a volume percent of each endmember. The 'forward analysis' of linear mixing (comparing the spectra of physical mixtures to numerical mixtures) has received much attention. The reverse approach of un-mixing thermal emission spectra was examined with remotely sensed data, but no laboratory verification exists. Understanding of the effects of spectral mixing on high resolution laboratory spectra allows for the extrapolation to lower resolution, and often more complicated, remotely gathered data. Thermal Infrared Multispectral Scanner (TIMS) data for Meteor Crater, Arizona were acquired in Sep. 1987. The spectral un-mixing of these data gives a unique test of the laboratory results. Meteor Crater (1.2 km in diameter and 180 m deep) is located in north-central Arizona, west of Canyon Diablo. The arid environment, paucity of vegetation, and low relief make the region ideal for remote data acquisition. Within the horizontal sedimentary sequence that forms the upper Colorado Plateau, the oldest unit sampled by the impact crater was the Permian Coconino Sandstone. A thin bed of the Toroweap Formation, also of Permian age, conformably overlays the Coconino. Above the Toroweap lies the Permian Kiabab Limestone which, in turn, is covered by a thin veneer of the Moenkopi Formation. The Moenkopi is Triassic in age and has two distinct sub-units in the vicinity of the crater. The lower Wupatki member is a fine

  18. Strawberry Crater Roadless Areas, Arizona

    SciTech Connect

    Wolfe, E.W.; Light, T.D.

    1984-01-01

    The results of a mineral survey conducted in 1980 in the Strawberry Crater Roadless Areas, Arizona, indicate little promise for the occurrence of metallic mineral or fossil fuel resources in the area. The area contains deposits of cinder, useful for the production of aggregate block, and for deposits of decorative stone; however, similar deposits occur in great abundance throughout the San Francisco volcanic field outside the roadless areas. There is a possibility that the Strawberry Crater Roadless Areas may overlie part of a crustal magma chamber or still warm pluton related to the San Francisco Mountain stratovolcano or to basaltic vents of late Pleistocene or Holocene age. Such a magma chamber or pluton beneath the Strawberry Crater Roadless Areas might be an energy source from which a hot-, dry-rock geothermal energy system could be developed, and a probable geothermal resource potential is therefore assigned to these areas.

  19. STRAWBERRY CRATER ROADLESS AREAS, ARIZONA.

    USGS Publications Warehouse

    Wolfe, Edward W.; Light, Thomas D.

    1984-01-01

    The results of a mineral survey conducted in the Strawberry Crater Roadless Areas, Arizona, indicate little promise for the occurrence of metallic mineral or fossil fuel resources in the area. The area contains deposits of cinder, useful for the production of aggregate block, and for deposits of decorative stone; however, similar deposits occur in great abundance throughout the San Francisco volcanic field outside the roadless areas. There is a possibility that the Strawberry Crater Roadless Areas may overlie part of a crustal magma chamber or still warm pluton related to the San Francisco Mountain stratovolcano or to basaltic vents of late Pleistocene or Holocene age. Such a magma chamber or pluton beneath the Strawberry Crater Roadless Areas might be an energy source from which a hot-, dry-rock geothermal energy system could be developed, and a probable geothermal resource potential is therefore assigned to these areas. 9 refs.

  20. Siderophile element fractionation in meteor crater impact glasses and metallic spherules

    NASA Technical Reports Server (NTRS)

    Mittlefehldt, David W.; See, T. H.; Scott, E. R. D.

    1993-01-01

    Meteor Crater, Arizona provides an opportunity to study, in detail, elemental fractionation processes occurring during impacts through the study of target rocks, meteorite projectile and several types of impact products. We have performed EMPA and INAA on target rocks, two types of impact glass and metallic spherules from Meteor Crater. Using literature data for the well studied Canyon Diablo iron we can show that different siderophite element fractionations affected the impact glasses than affected the metallic spherules. The impact glasses primarily lost Au, while the metallic spherules lost Fe relative to other siderophile elements.

  1. NASA Meteor Cam Video of June 2, 2016 Arizona Fireball

    NASA Video Gallery

    Video obtained from the NASA meteor camera situated at the MMT Observatory on the site of the Fred Lawrence Whipple Observatory, located on Mount Hopkins, Arizona, in the Santa Rita Mountains. Cred...

  2. Devolatilization or melting of carbonates at Meteor Crater, AZ?

    NASA Astrophysics Data System (ADS)

    Hörz, F.; Archer, P. D.; Niles, P. B.; Zolensky, M. E.; Evans, M.

    2015-06-01

    We have investigated the carbonates in the impact melts and in a monolithic clast of highly shocked Coconino sandstone of Meteor Crater, AZ to evaluate whether melting or devolatilization is the dominant response of carbonates during high-speed meteorite impact. Both melt- and clast-carbonates are calcites that have identical crystal habits and that contain anomalously high SiO2 and Al2O3. Also, both calcite occurrences lack any meteoritic contamination, such as Fe or Ni, which is otherwise abundantly observed in all other impact melts and their crystallization products at Meteor Crater. The carbon and oxygen isotope systematics for both calcite deposits suggest a low temperature environment (<100 °C) for their precipitation from an aqueous solution, consistent with caliche. We furthermore subjected bulk melt beads to thermogravimetric analysis and monitored the evolving volatiles with a quadrupole mass spectrometer. CO2 yields were <5 wt%, with typical values in the 2 wt% range; also total CO2 loss is positively correlated with H2O loss, an indication that most of these volatiles derive from the secondary calcite. Also, transparent glasses, considered the most pristine impact melts, yield 100 wt% element totals by EMPA, suggesting complete loss of CO2. The target dolomite decomposed into MgO, CaO, and CO2; the CO2 escaped and the CaO and MgO combined with SiO2 from coexisting quartz and FeO from the impactor to produce the dominant impact melt at Meteor Crater. Although confined to Meteor Crater, these findings are in stark contrast to Osinski et al. (2008) who proposed that melting of carbonates, rather than devolatilization, is the dominant process during hypervelocity impact into carbonate-bearing targets, including Meteor Crater.

  3. Meteor Crater: An Analog for Using Landforms to Reconstruct Past Hydrologic Conditions

    NASA Astrophysics Data System (ADS)

    Palucis, M. C.; Dietrich, W. E.; Howard, A. D.; Nishiizumi, K.; Caffee, M. W.; Kring, D. A.

    2015-12-01

    Recent work suggests that debris flow activity has occurred on Mars in the last few million years during high orbital obliquities, but estimating the amount and frequency of liquid water needed to generate these types of flows is still poorly constrained. While it is relatively common to estimate water amounts needed to produce landforms on Mars, such as gullies or alluvial fans, this is something rarely done on Earth. Consequently, there is little field data on the linkage between climate (snowmelt or rainfall events) and the amount of runoff needed to produce specific volumes of sediment in a landform. Here, we present field and modeling data from Meteor Crater, which is a ~50,000 year old impact crater in northern Arizona (USA). Though it is very well preserved, it has developed gullies along its inner wall, similar in form to many gullies on Mars. Meteor Crater, similar to many Martian craters, has also gone through a change in a climate based on the ~30 m of lake sediments on its now dry floor, and what has eroded from its walls has deposited on its floor, making it a closed system. We show using LiDAR-derived topographic data and field observations that debris flows, likely generated by runoff entrainment into talus bordering bedrock cliffs of the crater walls, drove erosion and deposition processes at Meteor Crater. Cosmogenic dating of levee deposits indicates that debris flows ceased in the early Holocene, synchronous with regional drying. For a water-to-rock ratio of 0.3 at the time of transport, which is based on data from rotating drum experiments, it would have taken ~150,000 m3 of water to transport the estimated ~500,000 m3 of debris flow deposits found at the surface of the crater floor. This extensive erosion would require less than 0.4 m of total runoff over the 0.35 km2 upslope source area of the crater, or ~26 mm of runoff per debris flow event. Much more runoff did occur however, as evidenced by lake deposits on the crater floor and Holocene

  4. Katabatically Driven Downslope Windstorm-Type Flows on the Inner Sidewall of Arizona's Barringer Meteorite Crater

    NASA Astrophysics Data System (ADS)

    Whiteman, C. D.; Lehner, M.; Hoch, S.; Hills, M.; Haiden, T.; Feigenwinter, I.; Grudzielanek, M.; Maric, M.; Kalthoff, N.; Vogt, R.; Cermak, J.; Rotunno, R.; Calhoun, R.; Cherukuru, N.; Adler, B.

    2015-12-01

    The second Meteor Crater Experiment (METCRAX II) conducted in October 2013 at Arizona's Barringer Meteorite Crater investigated hydraulic-analogue atmospheric flows that cascade into the crater basin over its southwest rim. These intruding downslope windstorm-type flows are produced when the depth of the temperature inversion and accompanying southwesterly downslope flow on the surrounding gently sloping plain exceeds the height of the crater rim. As the southwesterly katabatic flow approaches the crater it decelerates, splits around the crater at elevations below the crater rim, and cascades over the crater rim at upper elevations. The intruding cold katabatic air accelerates down the inner sidewall of the crater, perturbing the prexisting shallow inversion on the crater floor, sometimes creating the atmospheric equivalent of ocean or lake basin seiches. When the cold air intrusions are strong, warm air is brought down into the crater from the upwind atmosphere above the mesoscale inversion, and hydraulic jumps may form on the southwest side of the crater while leaving the rest of the crater atmosphere relatively undisturbed. In this talk, evidence for these flow features will be presented, featuring dual Doppler and time-lapse IR animations of the intruding flows.

  5. Meteor Crater: Energy of formation - Implications of centrifuge scaling

    NASA Technical Reports Server (NTRS)

    Schmidt, R. M.

    1980-01-01

    Recent work on explosive cratering has demonstrated the utility of performing subscale experiments on a geotechnic centrifuge to develop scaling rules for very large energy events. The present investigation is concerned with an extension of this technique to impact cratering. Experiments have been performed using a projectile gun mounted directly on the centrifuge rotor to launch projectiles into a suitable soil container undergoing centripetal accelerations in excess of 500 G. The pump tube of a two-stage light-gas gun was used to attain impact velocities of approximately 2 km/sec. The results of the experiments indicate that the energy of formation of any large impact crater depends upon the impact velocity. This dependence, shown for the case of Meteor Crater, is consistent with analogous results for the specific energy dependence of explosives and is expected to persist to impact velocities in excess of 25 km/sec.

  6. Fractal Fragmentation triggered by meteor impact: The Ries Crater (Germany)

    NASA Astrophysics Data System (ADS)

    Paredes Marino, Joali; Perugini, Diego; Rossi, Stefano; Kueppers, Ulrich

    2015-04-01

    FRACTAL FRAGMENTATION TRIGGERED BY METEOR IMPACT: THE RIES CRATER (GERMANY) Joali Paredes (1), Stefano Rossi (1), Diego Perugini (1), Ulrich Kueppers (2) 1. Department of Physics and Geology, University of Perugia, Italy 2. Department of Earth and Environmental Sciences, University of Munich, Germany The Nördlinger Ries is a large circular depression in western Bavaria, Germany. The depression was caused by a meteor impact, which occurred about 14.3 million-14.5 million years ago. The original crater rim had an estimated diameter of 24 kilometers. Computer modeling of the impact event indicates that the impact or probably had diameters of about 1.5 kilometers and impacted the target area at an angle around 30 to 50 degrees from the surface in a west- southwest to east-northeast direction. The impact velocity is thought to have been about 20 km/s. The meteor impact generated extensive fragmentation of preexisting rocks. In addition, melting of these rocks also occurred. The impact melt was ejected at high speed provoking its extensive fragmentation. Quenched melt fragments are ubiquitous in the outcrops. Here we study melt fragment size distributions with the aim of understanding the style of melt fragmentation during ejection and to constrain the rheological properties of such melts. Digital images of suevite (i.e. the rock generated after deposition and diagenesis of ash and fragments produced by the meteor impact) were obtained using a high-resolution optical scanner. Successively, melt fragments were traced by image analysis and the images segmented in order to obtain binary images on which impact melt fragments are in black color, embedded on a white background. Hence, the size of fragments was determined by image analysis. Fractal fragmentation theory has been applied to fragment size distributions of melt fragments in the Ries crater. Results indicate that melt fragments follow fractal distributions indicating that fragmentation of melt generated by the

  7. Creation of High Resolution Terrain Models of Barringer Meteorite Crater (Meteor Crater) Using Photogrammetry and Terrestrial Laser Scanning Methods

    NASA Technical Reports Server (NTRS)

    Brown, Richard B.; Navard, Andrew R.; Holland, Donald E.; McKellip, Rodney D.; Brannon, David P.

    2010-01-01

    Barringer Meteorite Crater or Meteor Crater, AZ, has been a site of high interest for lunar and Mars analog crater and terrain studies since the early days of the Apollo-Saturn program. It continues to be a site of exceptional interest to lunar, Mars, and other planetary crater and impact analog studies because of its relatively young age (est. 50 thousand years) and well-preserved structure. High resolution (2 meter to 1 decimeter) digital terrain models of Meteor Crater in whole or in part were created at NASA Stennis Space Center to support several lunar surface analog modeling activities using photogrammetric and ground based laser scanning techniques. The dataset created by this activity provides new and highly accurate 3D models of the inside slope of the crater as well as the downslope rock distribution of the western ejecta field. The data are presented to the science community for possible use in furthering studies of Meteor Crater and impact craters in general as well as its current near term lunar exploration use in providing a beneficial test model for lunar surface analog modeling and surface operation studies.

  8. Formation of the central uplift in meteoric craters

    NASA Technical Reports Server (NTRS)

    Ivanov, B. A.; Bazilevskiy, A. T.; Sazonova, L. V.

    1986-01-01

    Data are presented on the sizes of impact craters with central uplifts on the earth, moon, and terrestrial planets. It is proposed that the central uplift of the Kara crater in the USSR was formed by impact metamorphism of rocks along a crater having a depth of about 600 meters. A theoretical analysis of the mechanics of hypervelocity impact cratering is used to investigate the features of shock-wave attenuation in the depths of the target and the amount of impact melt formed during this process. An attempt is made to determine the velocity of rock motion during the formation of central uplifts in terrestrial craters.

  9. Meteor storm evidence against the recent formation of lunar crater Giordano Bruno

    NASA Astrophysics Data System (ADS)

    Withers, Paul

    2001-04-01

    It has been suggested that the formation of the 22 km diameter lunar crater Giordano Bruno was witnessed in June 1178 A.D. To date, this hypothesis has not been well tested. Such an impact on the Earth would be "civilization threatening". Previous studies have shown that the formation of Giordano Bruno would lead to the arrival of 10 million tonnes of ejecta in the Earth's atmosphere in the following week. I calculate that this would cause a week-long meteor storm potentially comparable to the peak of the 1966 Leonids storm. The lack of any known historical records of such a storm is evidence against the recent formation of Giordano Bruno. Other tests of the hypothesis are also discussed, with emphasis on the lack of corroborating evidence for a very recent formation of the crater.

  10. Williston basin. Milestone test renews interest in Red Wing Creek field's meteor crater

    SciTech Connect

    Rountree, R.

    1983-04-01

    New drilling in the vicinity of Red Wing Creek field in McKenzie County, North Dakota has renewed interest in an area that has intrigued geologists for a number of years. Red Wing Creek was discovered in 1972 by True Oil Co. and has demonstrated better per-acre oil recovery than any other oil field in the Williston Basin. Fully developed several years ago, the field produces from what has been described as the central peak of an astrobleme, within a meteor crater. The current test by Milestone Petroleum Inc. is permitted to 14,200 ft and is being drilled on the rim of the crater, in SW SW 35-148n-101w, approx. a mile south of Red Wing production. The primary objective is the Ordovician Red River; but plans call for drilling deeper, through the Winnipeg, to below the Mississippian sediments that produce at Red Wing Creek field. At least 3 unsuccessful Red River tests have been drilled in or near the field in earlier years, but not in the area where Milestone is drilling. Production at Red Wing has come from porosity zones in a Mississippian oil column that measured 2600 ft in the original well; the better wells are in the heart of the field, on a rebound cone in the center of the crater.

  11. High Resolution Magnetic and Gravity Surveys to Constrain Maar Geometry and Eruption Mechanisms, Rattlesnake Crater, Arizona

    NASA Astrophysics Data System (ADS)

    Marshall, A. M.; Kruse, S. E.; Connor, C.; Connor, L.; Abdollahzadeh, M.; Harburger, A.; Richardson, J. A.; Courtland, L. M.; Farrell, A. K.; Kiflu, H. G.; Malservisi, R.; McNiff, C. M.; Njoroge, M.; Nushart, N.; Rookey, K.

    2013-12-01

    Located 25 kilometers east of Flagstaff, Arizona, Rattlesnake Crater is an oblong phreatomagmatic feature in the San Francisco Volcanic Field. The shallow crater is approximately 1.4 kilometers at its widest point, and surrounded by an uneven tuff ring which is overlapped by a scoria cone volcano on the southeastern side. Improved understanding of its formation and evolution requires geophysical study because there are very few outcrops, and no digging is permitted on site. Geologic features related to the crater are further obscured by deposits from the overlapping scoria cone, as well as tephra from eruptions at nearby Sunset Crater. We present the results of a detailed magnetic and gravity survey in and around Rattlesnake Crater. A substantial NW-SE trending elongate magnetic anomaly (1400 nT) and a smaller similarly trending anomaly are observed inside the crater, as well as a longer wavelength positive gravitational anomaly (+1.0-1.5 mGal) across the crater. The magnetic survey was completed on foot with a 50 meter line spacing inside the crater, and 100 meter line spacing across a portion of the surrounding area outside the crater. The gravity survey was done on two intersecting survey lines - one running west to east, and another roughly north to south, with recordings every 100 meters extending at least 1000 meters outside the crater in all four directions. 2D models of the magnetic and gravity data are presented illustrating the possible geometry of the diatreme, and the approximate size and shape of the major intrusive features. Eruption estimates based on the models are calculated, and the models are favorably compared to the size and depth estimates given in a recent publication (Valentine 2012) that used xenolith content to estimate the size and depth of the diatreme.

  12. Impact melt- and projectile-bearing ejecta at Barringer Crater, Arizona

    NASA Astrophysics Data System (ADS)

    Osinski, Gordon R.; Bunch, Ted E.; Flemming, Roberta L.; Buitenhuis, Eric; Wittke, James H.

    2015-12-01

    Our understanding of the impact cratering process continues to evolve and, even at well-known and well-studied structures, there is still much to be learned. Here, we present the results of a study on impact-generated melt phases within ejecta at Barringer Crater, Arizona, one of the first impact craters on Earth to be recognized and arguably the most famous. We report on previously unknown impact melt-bearing breccias that contain dispersed fragments of the projectile as well as impact glasses that contain a high proportion of projectile material - higher than any other glasses previously reported from this site. These glasses are distinctly different from so-called "melt beads" that are found as a lag deposit on the present-day erosion surface and that we also study. It is proposed that the melts in these impact breccias were derived from a more constrained sub-region of the melt zone that was very shallow and that also had a larger projectile contribution. In addition to low- and high-Fe melt beads documented previously, we document Ca-Mg-rich glasses and calcite globules within silicate glass that provide definitive evidence that carbonates underwent melting during the formation of Barringer Crater. We propose that the melting of dolomite produces Ca-Mg-rich melts from which calcite is the dominant liquidus phase. This explains the perhaps surprising finding that despite dolomite being the dominant rock type at many impact sites, including Barringer Crater, calcite is the dominant melt product. When taken together with our estimate for the amount of impact melt products dispersed on, and just below, the present-day erosional surface, it is clear that the amount of melt produced at Barringer Crater is higher than previously estimated and is more consistent with recent numerical modeling studies. This work adds to the growing recognition that sedimentary rocks melt during hypervelocity impact and do not just decompose and/or devolatilize as was previously thought

  13. 'Big Crater' in 360-degree panorama

    NASA Technical Reports Server (NTRS)

    1997-01-01

    The crater dubbed 'Big Crater', approximately 2200 meters (7200 feet)away was imaged by the Imager for Mars Pathfinder (IMP) as part of a 360-degree color panorama, taken over sols 8, 9 and 10. 'Big Crater' is actually a relatively small Martian crater to the southeast of the Mars Pathfinder landing site. It is 1500 meters (4900 feet) in diameter, or about the same size as Meteor Crater in Arizona.

    Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. JPL is an operating division of the California Institute of Technology (Caltech). The Imager for Mars Pathfinder (IMP) was developed by the University of Arizona Lunar and Planetary Laboratory under contract to JPL. Peter Smith is the Principal Investigator.

  14. Impact Crater

    NASA Technical Reports Server (NTRS)

    2002-01-01

    [figure removed for brevity, see original site]

    Today marks the 45th anniversary of the dawn of the Space Age (October 4, 1957). On this date the former Soviet Union launched the world's first satellite, Sputnik 1. Sputnik means fellow traveler. For comparison Sputnik 1 weighed only 83.6 kg (184 pounds) while Mars Odyssey weighs in at 758 kg (1,671 pounds).

    This scene shows several interesting geologic features associated with impact craters on Mars. The continuous lobes of material that make up the ejecta blanket of the large impact crater are evidence that the crater ejecta were fluidized upon impact of the meteor that formed the crater. Volatiles within the surface mixed with the ejecta upon impact thus creating the fluidized form. Several smaller impact craters are also observed within the ejecta blanket of the larger impact crater giving a relative timing of events. Layering of geologic units is also observed within the large impact crater walls and floor and may represent different compositional units that erode at variable rates. Cliff faces, dissected gullies, and heavily eroded impact craters are observed in the bottom half of the image at the terminus of a flat-topped plateau.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS

  15. Measurement of airborne particle concentrations near the Sunset Crater volcano, Arizona.

    PubMed

    Benke, Roland R; Hooper, Donald M; Durham, James S; Bannon, Donald R; Compton, Keith L; Necsoiu, Marius; McGinnis, Ronald N

    2009-02-01

    Direct measurements of airborne particle mass concentrations or mass loads are often used to estimate health effects from the inhalation of resuspended contaminated soil. Airborne particle mass concentrations were measured using a personal sampler under a variety of surface-disturbing activities within different depositional environments at both volcanic and nonvolcanic sites near the Sunset Crater volcano in northern Arizona. Focused field investigations were performed at this analog site to improve the understanding of natural and human-induced processes at Yucca Mountain, Nevada. The level of surface-disturbing activity was found to be the most influential factor affecting the measured airborne particle concentrations, which increased over three orders of magnitude relative to ambient conditions. As the surface-disturbing activity level increased, the particle size distribution and the majority of airborne particle mass shifted from particles with aerodynamic diameters less than 10 mum (0.00039 in) to particles with aerodynamic diameters greater than 10 mum (0.00039 in). Under ambient conditions, above average wind speeds tended to increase airborne particle concentrations. In contrast, stronger winds tended to decrease airborne particle concentrations in the breathing zone during light and heavy surface-disturbing conditions. A slight increase in the average airborne particle concentration during ambient conditions was found above older nonvolcanic deposits, which tended to be finer grained than the Sunset Crater tephra deposits. An increased airborne particle concentration was realized when walking on an extremely fine-grained deposit, but the sensitivity of airborne particle concentrations to the resuspendible fraction of near-surface grain mass was not conclusive in the field setting when human activities disturbed the bulk of near-surface material. Although the limited sample size precluded detailed statistical analysis, the differences in airborne particle

  16. Salt-bearing fumarole deposits in the summit crater of Oldoinyo Lengai, Northern Tanzania: interactions between natrocarbonatite lava and meteoric water

    NASA Astrophysics Data System (ADS)

    Genge, M. J.; Balme, M.; Jones, A. P.

    2001-04-01

    Oldoinyo Lengai in the Northern Tanzania rift is the only active nephelinite-carbonatite stratovolcano. We report the discovery of thermonatrite, aphthitalite, halite and sylvite fumarole deposits on recent natrocarbonatite lava flows erupted in the summit crater during the wet season. These salt deposits occur as delicate, concave fringes or tubes that line the cooling cracks in the lava flows and consist of intergrowths of euhedral crystals. The presence of a dark altered zone, depleted in halides and alkalies, adjacent to cooling cracks and observations of steam fumaroles emanating from the fractures suggest that the salts are formed by sublimation from saturated vapours generated by the extrusion of lavas over meteoric water. The crystallisation sequence recorded in the salts suggests that mixing between meteoric steam and magmatic CO 2 and H 2S occurs at high temperatures resulting in the sublimation of carbonates and sulphates. At lower temperatures the vapours are dominated by meteoric steam and sublimate halides. The high solubility of the fumarole salts within meteoric water and their formation only during the wet season implies that these are ephemeral deposits that are unlikely to be preserved in the geological record.

  17. Tephra Blanket Record of a Violent Strombolian Eruption, Sunset Crater, Arizona

    NASA Astrophysics Data System (ADS)

    Wagner, K. D.; Ort, M. H.

    2015-12-01

    New fieldwork provides a detailed description of the widespread tephra of the ~1085 CE Sunset Crater eruption in the San Francisco Volcanic Field, Arizona, and refines interpretation of the eruptive sequence. The basal fine-lapilli tephra-fall-units I-IV are considered in detail. Units I and II are massive, with Unit I composed of angular to spiny clasts and II composed of more equant, oxidized clasts. Units III and IV have inversely graded bases and massive tops and are composed of angular to spiny iridescent and mixed iridescent and oxidized angular clasts, respectively. Xenoliths are rare in all units (<0.1%): sedimentary xenoliths are consistent with the known shallow country rock (Moenkopi and Kaibab Fms); magmatic xenoliths are pumiceous rhyolite mingled with basalt. Unit II is less sideromelane rich (20%) than Units I, III, and IV (60-80%). Above these units are at least two more coarse tephra-fall units. Variably preserved ash and fine-lapilli laminae cap the tephra blanket. This deposit is highly susceptible to reworking, and likely experienced both syn- and post-eruptive aeolian redistribution. It appears as either well sorted, alternating planar-parallel beds of ash and fine lapilli with rare wavy beds, or as cross- or planar-bedded ash. The tephra blanket as a whole is stratigraphically underlain by a fissure-fed lava flow and lapilli-fall units are intercalated with two larger flows. Mean grain size is coarsest in Unit I but coarsens in Units II-IV. Units I, III, and IV are moderately to poorly sorted with no skew. Unit II is better sorted and more coarse-skewed. Units I and III are slightly more platykurtic than II and IV. Without considering possible spatial effects introduced by dispersion patterns, bootstrap ANOVA confidence intervals suggest at least Unit II sorting and skewness are from distinct populations. Isopachs indicate Units I and II were associated with a 10-km-long fissure source. After or during Unit II's deposition, activity localized

  18. Degradation of selected terrestrial and Martian impact craters

    NASA Astrophysics Data System (ADS)

    Grant, J. A.; Schultz, P. H.

    1993-06-01

    The history of degradation of 50,000-yr-old 1.2-km-diam Meteor Crater in Arizona is defined using field mapping, and the degradation states of the progressively more degraded 68,000-yr-old 1.8-km-diam Lonar Crater in Indiana and 0.5-3.0 Myr old 1.75-km-diam Talemzane Crater in Algeria are assessed using air photos. The results on these terrestrial craters are then compared with the gradational morphology associated with craters in southern Ismenius Lacus on Mars, in order to develop first-order constraints on gradational activity. Common degradation signatures associated with craters on both planets are described. These signatures are used to assemble a first-order degradational sequence for the terrestrial craters that is then compared with the Martian degradational signatures to infer past processes and climate.

  19. Degradation of selected terrestrial and Martian impact craters

    NASA Technical Reports Server (NTRS)

    Grant, John A.; Schultz, Peter H.

    1993-01-01

    The history of degradation of 50,000-yr-old 1.2-km-diam Meteor Crater in Arizona is defined using field mapping, and the degradation states of the progressively more degraded 68,000-yr-old 1.8-km-diam Lonar Crater in Indiana and 0.5-3.0 Myr old 1.75-km-diam Talemzane Crater in Algeria are assessed using air photos. The results on these terrestrial craters are then compared with the gradational morphology associated with craters in southern Ismenius Lacus on Mars, in order to develop first-order constraints on gradational activity. Common degradation signatures associated with craters on both planets are described. These signatures are used to assemble a first-order degradational sequence for the terrestrial craters that is then compared with the Martian degradational signatures to infer past processes and climate.

  20. Impact Crater in Coastal Patagonia

    NASA Technical Reports Server (NTRS)

    D'Antoni, Hector L; Lasta, Carlos A.; Condon, Estelle (Technical Monitor)

    2000-01-01

    Impact craters are geological structures attributed to the impact of a meteoroid on the Earth's (or other planet's) surface (Koeberl and Sharpton. 1999). The inner planets of the solar system as well as other bodies such as our moon show extensive meteoroid impacts (Gallant 1964, French 1998). Because of its size and gravity, we may assume that the Earth has been heavily bombarded but weathering and erosion have erased or masked most of these features. In the 1920's, a meteor crater (Mark 1987) was identified in Arizona and to this first finding the identification of a large number of impact structures on Earth followed (Hodge 1994). Shock metamorphic effects are associated with meteorite impact craters. Due to extremely high pressures, shatter cones are produced as well as planar features in quartz and feldspar grains, diaplectic glass and high-pressure mineral phases such as stishovite (French 1998).

  1. Meteor Showers.

    ERIC Educational Resources Information Center

    Kronk, Gary W.

    1988-01-01

    Described are the history, formation, and observing techniques of meteors and comets. Provided are several pictures, diagrams, meteor organizations and publications, and meteor shower observation tables. (YP)

  2. Scoria Cone and Tuff Ring Stratigraphy Interpreted from Ground Penetrating Radar, Rattlesnake Crater, Arizona

    NASA Astrophysics Data System (ADS)

    Kruse, S. E.; McNiff, C. M.; Marshall, A. M.; Courtland, L. M.; Connor, C.; Charbonnier, S. J.; Abdollahzadeh, M.; Connor, L.; Farrell, A. K.; Harburger, A.; Kiflu, H. G.; Malservisi, R.; Njoroge, M.; Nushart, N.; Richardson, J. A.; Rookey, K.

    2013-12-01

    Numerous recent studies have demonstrated that detailed investigation of scoria cone and maar morphology can reveal rich details the eruptive and erosion histories of these volcanoes. A suite of geophysical surveys were conducted to images Rattlesnake Crater in the San Francisco Volcanic Field, AZ, US. We report here the results of ~3.4 km of ground penetrating radar (GPR) surveys that target the processes of deposition and erosion on the pair of cinder cones that overprint the southeast edge of Rattlesnake crater and on the tuff ring that forms the crater rim. Data were collected with 500, 250, 100, and 50 MHz antennas. The profiles were run in a radial direction down the northeast flanks of the cones (~1 km diameter, ~120 meters height) , and on the inner and outer margins of the oblong maar rim (~20-80 meters height). A maximum depth of penetration of GPR signal of ~15m was achieved high on the flanks of scoria cones. A minimum depth of essentially zero penetration occurred in the central crater. We speculate that maximum penetration occurs near the peaks of the cones and crater rim because ongoing erosion limits new soil formation. Soil formation would tend to increase surface conductivity and hence decrease GPR penetration. Soil is probably better developed within the crater, precluding significant radar penetration there. On the northeast side of the gently flattened rim of the easternmost scoria cone, the GPR profile shows internal layering that dips ~20 degrees northeast relative to the current ground surface. This clearly indicates that the current gently dipping surface is not a stratigraphic horizon, but reflects instead an erosive surface into cone strata that formed close to the angle of repose. Along much of the cone flanks GPR profiles show strata dipping ~4-5 degrees more steeply than the current surface, suggesting erosion has occurred over most of the height of the cone. An abrupt change in strata attitude is observed at the gradual slope

  3. Ground Water in the Wapatki and Sunset Crater National Monuments, Coconino County, Arizona

    USGS Publications Warehouse

    Cosner, Oliver J.

    1962-01-01

    The Wupatki and Sunset Crater National Monuments are 15 and 30 miles, respectively, northeast of Flagstaff on the San Francisco Plateau. They are in the eastern part of the San Francisco volcanic field and on the southwest flank of the Black Mesa basin. The Supai formation, Coconino sandstone, Kaibab limestone, Moenkopi formation, and Chinle formation are overlain in parts of the area by volcanic rocks and alluvium. The regional water table occurs chiefly in the Coconino sandstone at altitudes of about 5,000 feet at Sunset Crater, about 4,075 feet near Wupatki Ruin, and about 4,100 feet near Citadel Ruin. The general movement of the ground water is northeastward. Small supplies of perched water occur in the Moenkopi formation and in the alluvium, and perched water may be present locally in the volcanic rocks. The results of the field investigation indicated that adequate ground-water supplies were available from the Coconino sandstone to meet the needs of the National Monuments, and a well was drilled at the Wupatki Monument headquarters in 1958 to a total depth of 904 feet. It produced 50 gpm (gallons per minute) of water with 45 feet of drawdown from a static water level of 780 feet below land surface.

  4. Geochemical and C, O, Sr, and U-series isotopic evidence for the meteoric origin of calcrete at Solitario Wash, Crater Flat, Nevada, USA

    NASA Astrophysics Data System (ADS)

    Neymark, L. A.; Paces, J. B.; Marshall, B. D.; Peterman, Z. E.; Whelan, J. F.

    2005-08-01

    Calcite-rich soils (calcrete) in alluvium and colluvium at Solitario Wash, Crater Flat, Nevada, USA, contain pedogenic calcite and opaline silica similar to soils present elsewhere in the semi-arid southwestern United States. Nevertheless, a ground-water discharge origin for the Solitario Wash soil deposits was proposed in a series of publications proposing elevation-dependent variations of carbon and oxygen isotopes in calcrete samples. Discharge of ground water in the past would raise the possibility of future flooding in the unsaturated zone at Yucca Mountain, Nevada, site of a proposed high-level nuclear waste repository. New geochemical and carbon, oxygen, strontium, and uranium-series isotopic data disprove the presence of systematic elevation-isotopic composition relations, which are the main justification given for a proposed ground-water discharge origin of the calcrete deposits at Solitario Wash. Values of δ13C (-4.1 to -7.8 per mil [‰]), δ18O (23.8-17.2‰), 87Sr/86Sr (0.71270-0.71146), and initial 234U/238U activity ratios of about 1.6 in the new calcrete samples are within ranges previously observed in pedogenic carbonate deposits at Yucca Mountain and are incompatible with a ground-water origin for the calcrete. Variations in carbon and oxygen isotopes in Solitario Wash calcrete likely are caused by pedogenic deposition from meteoric water under varying Quaternary climatic conditions over hundreds of thousands of years.

  5. Geochemical and C, O, Sr, and U-series isotopic evidence for the meteoric origin of calcrete at Solitario Wash, Crater Flat, Nevada, USA

    USGS Publications Warehouse

    Neymark, L.A.; Paces, J.B.; Marshall, B.D.; Peterman, Z.E.; Whelan, J.F.

    2005-01-01

    Calcite-rich soils (calcrete) in alluvium and colluvium at Solitario Wash, Crater Flat, Nevada, USA, contain pedogenic calcite and opaline silica similar to soils present elsewhere in the semi-arid southwestern United States. Nevertheless, a ground-water discharge origin for the Solitario Wash soil deposits was proposed in a series of publications proposing elevation-dependent variations of carbon and oxygen isotopes in calcrete samples. Discharge of ground water in the past would raise the possibility of future flooding in the unsaturated zone at Yucca Mountain, Nevada, site of a proposed high-level nuclear waste repository. New geochemical and carbon, oxygen, strontium, and uranium-series isotopic data disprove the presence of systematic elevation-isotopic composition relations, which are the main justification given for a proposed ground-water discharge origin of the calcrete deposits at Solitario Wash. Values of ??13C (-4.1 to -7.8 per mil [???]), ??18O (23.8-17.2???), 87Sr/ 86Sr (0.71270-0.71146), and initial 234U/238U activity ratios of about 1.6 in the new calcrete samples are within ranges previously observed in pedogenic carbonate deposits at Yucca Mountain and are incompatible with a ground-water origin for the calcrete. Variations in carbon and oxygen isotopes in Solitario Wash calcrete likely are caused by pedogenic deposition from meteoric water under varying Quaternary climatic conditions over hundreds of thousands of years. ?? Springer-Verlag 2005.

  6. Origin of the 'dike-like' structure and transitions in eruptive styles at Colton Crater, northern Arizona: San Francisco Volcanic Field REU

    NASA Astrophysics Data System (ADS)

    Witter, M. R.; Ort, M. H.; Leudemann, L. A.

    2013-12-01

    Colton Crater, located within the San Francisco Volcanic Field (SFVF) in northern Arizona, is one of over 600 scoria cones in the field. Unlike most other volcanoes in the SFVF, Colton Crater is characterized as a hybrid volcano that had Strombolian, Hawaiian, and Surtseyan explosions. Surtseyan explosions led to the excavation of the center of the volcano, creating a large 1.3-km-diameter crater with a 30-m post-phreatomagmatic scoria cone at its center. A vertical erosion-resistant feature along the northern rim of the crater, originally mapped as a dike, provides valuable information about the sequence and timing of the transition to phreatomagmatic eruptions because it disrupts the otherwise continuous spatter layers deposited just prior to that change. Stratigraphic sections and paleomagnetic analysis of Colton Crater reveal the origin and timing of emplacement of this vertical structure and its place in the transitional eruptive history. The prominent upper layers in the crater walls show some variation throughout the crater, but generally are composed of agglutinated spatter, welded scoria and bombs, and rootless lava flows. The uppermost portion of the outward-dipping spatter layers that lie between the two saddles on the northern rim closely match the layers observed in the vertical structure, revealing that the structure is a section of rotated spatter. The characteristic remanent magnetization (ChRM), identified using alternating field (AF) demagnetization, shows the timing of the displacement of sections of the agglutinated spatter and welded cinder. Sites along the vertical structure yield ChRMs statistically identical to non-rotated sites, which indicates that rotation of the vertical structure occurred before the ChRM had been set, i.e., the layers were above the Curie temperature during rotation. The eruption started as Strombolian and Hawaiian perhaps because the flux of magma overpowered the influx of water from local aquifer formations, creating

  7. Subsurface structure of a maar-diatreme and associated tuff ring from a high-resolution geophysical survey, Rattlesnake Crater, Arizona

    NASA Astrophysics Data System (ADS)

    Marshall, Anita; Connor, Charles; Kruse, Sarah; Malservisi, Rocco; Richardson, Jacob; Courtland, Leah; Connor, Laura; Wilson, James; Karegar, Makan A.

    2015-10-01

    Geophysical survey techniques including gravity, magnetics, and ground penetrating radar were utilized to study the diatreme and tuff ring at Rattlesnake Crater, a maar in the San Francisco Volcanic Field of northern Arizona. Significant magnetic anomalies (+ 1600 nT) and a positive gravity anomaly (+ 1.4 mGal) are associated with the maar. Joint modeling of magnetic and gravity data indicate that the diatreme that underlies Rattlesnake Crater has volume of 0.8-1 km3, and extends to at least 800 m depth. The modeled diatreme comprises at least two zones of variable density and magnetization, including a low density, highly magnetized unit near the center of the diatreme, interpreted to be a pyroclastic unit emplaced at sufficiently high temperature and containing sufficient juvenile fraction to acquire thermal remanent magnetization. Magnetic anomalies and ground penetrating radar (GPR) imaging demonstrate that the bedded pyroclastic deposits of the tuff ring also carry high magnetization, likely produced by energetic emplacement of hot pyroclastic density currents. GPR profiles on the tuff ring reveal long (~ 100 m) wavelength undulations in bedding planes. Elsewhere, comparable bedforms have been interpreted as base surge deposits inflated by air entrainment from eruption column collapse. Interpretation of these geophysical data suggests that Rattlesnake Crater produced highly energetic phreatomagmatic activity that gave way to less explosive activity as the eruption progressed. The positive gravity anomaly associated with the maar crater is interpreted to be caused by coherent bodies within the diatreme and possibly lava ponding on the crater floor. These dense magnetized bodies have excess mass of 2-4 × 1010 kg, and occupy approximately 5% of the diatreme by volume. Magnetic anomalies on the crater floor are elongate NW-SE, suggesting that the eruption may have been triggered by the interaction of ascending magma with water in fractures of this orientation

  8. Meteor myths.

    NASA Astrophysics Data System (ADS)

    Hughes, D.

    1989-11-01

    The falling stars or meteors have long inspired folkloric imagery and superstition. All cultures, it seems, have produced their meteor myths and stories. In this article the reasoning behind the many strange ideas inspired by the meteor images is expanded and explored.

  9. Partially-Exhumed Crater in Northern Terra Meridiani: Stereo Anaglyph of overlapping coverage in

    NASA Technical Reports Server (NTRS)

    2002-01-01

    MGS MOC Release No. MOC2-316, 8 August 2002 Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) images have shown time and again that the geology and history of Mars is complex. These two pictures show different views of a circular feature in northern Terra Meridiani at 2.3oN, 356.6oW. The first is a mosaic of 3 MOC narrow angle images acquired in August 1999, November 2000, and June 2002. The black area is a gap in coverage resulting from data lost after transmission from Mars to Earth. The second picture is a stereo ('3-D') anaglyph of a portion of the same circular feature. It has been rotated 90o clockwise to show the stereo effect that results from combining the August 1999 image, which was taken while the spacecraft was pointed nadir (straight down) and the June 2002 image, taken with the spacecraft pointing backwards about 16o (i.e., MGS Relay-16 orientation). The anaglyph should be viewed with '3-D' glasses (red in left eye, blue in the right). The circular feature was once an impact crater. The crater was 2.6 km (1.6 mi) across, about 2.6 times larger than the famous Meteor Crater in northern Arizona. Terra Meridiani, like northern Arizona, is a region of vast exposures of layered sedimentary rock. Like the crater in Arizona, this one was formed by a meteor that impacted a layered rock substrate. Later, this crater was filled and completely buried under more than 100 m (more than 327 ft) of additional layered sediment. The sediment hardened to become rock. Later still, the rock was eroded away--by processes unknown (perhaps wind)--to re-expose the buried crater. The crater today remains mostly filled with sediment, its present rim standing only about 40 m (130 ft) above its surroundings.

  10. Secrets of the Wabar craters

    USGS Publications Warehouse

    Wynn, Jeffrey C.; Shoemaker, Eugene M.

    1997-01-01

    Focuses on the existence of craters in the Empty Quarter of Saudi Arabia created by the impact of meteors in early times. Mars Pathfinder and Mars Global Surveyor's encounter with impact craters; Elimination of craters in the Earth's surface by the action of natural elements; Impact sites' demand for careful scientific inspections; Location of the impact sites.

  11. Impact Craters in North America

    NASA Astrophysics Data System (ADS)

    Grieve, R. A. F.; Wood, C. A.; Garvin, J. B.; McLaughlin, G.; McHone, J. F.

    1988-03-01

    Meteor Crater Upheaval Dome Sierra Madera Middlesboro Pilot Lake Carswell Gow Lake Deep Bay Nicholson Lake West Hawk Lake Haughton Sudbury Wanapitei Brent Lac Couture New Quebec Clearwater Lakes Manicouagan Charlevoix Lac La Moinerie Mistastin

  12. Primordial Cratering Regimes on Planets

    NASA Astrophysics Data System (ADS)

    Hartmann, W. K.

    2004-11-01

    Understanding of planetary surface evolution (and possibly biological evolution) is hampered by a longstanding uncertainty over the nature of impact cratering and interplanetary debris in the first 600 My of solar system history. On the one hand, a number of researchers (1-3) treat a cataclysmic spike in cratering 3.9 Gy ago as an observational fact, arguing that little or no cratering occurred from 4.5 to 4.0 Gy ago, and that all multi-ring lunar basins formed 3.85 to 4.0 Gy ago. On the other hand, dynamical theorists have had problems trying to explain the a large impactor spike, as reviewed in (4). Worse yet, meteorite evidence on lunar and asteroidal impact melts (3,5) fail to confirm the strong spike in Apollo-sample impact melts at 3.9 Gy. A semi-quantitative model has been suggested to reconcile the findings (5). References: (1) Tera, F., D.A. Papanastassiou, G. J. Wasserberg 1974. Isotopic evidence for a terminal Lunar cataclysm, Earth Planet. Sci. Lett. 22, 1-21. (2) Stoeffler, D., G. Ryder 2001. "Stratigraphy and Isotope Ages of Lunar Geologic Units: Chronological Standard for the Inner Solar System," in Chronology and Evolution of Mars, Eds. R. Kallenbach, J. Geiss, W. K. Hartmann. Kluwer Academic Publishers, Netherlands, pp. 105-164. (3) Cohen, B. A., T. D. Swindle, D. A. Kring 2000. Support for the Lunar Cataclysm Hypothesis from Lunar Meteorite Impact Melt Ages. Science 290, 1754-1756. (4) Hartmann, W. K., G. Ryder, L. Dones, D. Grinspoon 2000. The Time-Dependent Intense Bombardment of the Primordial Earth/Moon System. In Origin of the Earth and Moon, Eds. R. M. Canup, K. Righter (Tucson: Univ. Arizona Press), pp. 493-512. (5) Hartmann, W. K. 2003. Megaregolith evolution and cratering cataclysm models - Lunar cataclysm as a misconception (28 years later). Meteor. Planet. Sci. 38, 579-593.

  13. Southern Crater

    NASA Technical Reports Server (NTRS)

    2005-01-01

    [figure removed for brevity, see original site] Context image for PIA03583 Southern Crater

    This crater is located south of Agassiz Crater. It is likely that the polar freeze/thaw/frost cycle is responsible for unusual appearance of the ejecta region around the crater.

    Image information: VIS instrument. Latitude 76.2S, Longitude 247.8E. 17 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  14. Crater Chains

    NASA Technical Reports Server (NTRS)

    2003-01-01

    [figure removed for brevity, see original site]

    The large crater at the top of this THEMIS visible image has several other craters inside of it. Most noticeable are the craters that form a 'chain' on the southern wall of the large crater. These craters are a wonderful example of secondary impacts. They were formed when large blocks of ejecta from an impact crashed back down onto the surface of Mars. Secondaries often form radial patterns around the impact crater that generated them, allowing researchers to trace them back to their origin.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

    Image information: VIS instrument. Latitude 19.3, Longitude 347.5 East (12.5 West). 19 meter/pixel resolution.

  15. Meteor44 Video Meteor Photometry

    NASA Technical Reports Server (NTRS)

    Swift, Wesley R.; Suggs, Robert M.; Cooke, William J.

    2004-01-01

    Meteor44 is a software system developed at MSFC for the calibration and analysis of video meteor data. The dynamic range of the (8bit) video data is extended by approximately 4 magnitudes for both meteors and stellar images using saturation compensation. Camera and lens specific saturation compensation coefficients are derived from artificial variable star laboratory measurements. Saturation compensation significantly increases the number of meteors with measured intensity and improves the estimation of meteoroid mass distribution. Astrometry is automated to determine each image's plate coefficient using appropriate star catalogs. The images are simultaneously intensity calibrated from the contained stars to determine the photon sensitivity and the saturation level referenced above the atmosphere. The camera s spectral response is used to compensate for stellar color index and typical meteor spectra in order to report meteor light curves in traditional visual magnitude units. Recent efforts include improved camera calibration procedures, long focal length 'streak' meteor photometry and two-station track determination. Meteor44 has been used to analyze data from the 2001, 2002 and 2003 MSFC Leonid observational campaigns as well as several lesser showers. The software is interactive and can be demonstrated using data from recent Leonid campaigns.

  16. Meteor44 Video Meteor Photometry

    NASA Technical Reports Server (NTRS)

    Swift, Wesley R.; Suggs, Robert M.; Cooke, William J.

    2004-01-01

    Meteor44 is a software system developed at MSFC for the calibration and analysis of video meteor data. The dynamic range of the (8bit) video data is extended by approximately 4 magnitudes for both meteors and stellar images using saturation compensation. Camera and lens specific saturation compensation coefficients are derived from artificial variable star laboratory measurements. Saturation compensation significantly increases the number of meteors with measured intensity and improves the estimation of meteoroid mass distribution. Astrometry is automated to determine each image s plate coefficient using appropriate star catalogs. The images are simultaneously intensity calibrated from the contained stars to determine the photon sensitivity and the saturation level referenced above the atmosphere. The camera s spectral response is used to compensate for stellar color index and typical meteor spectra in order to report meteor light curves in traditional visual magnitude units. Recent efforts include improved camera calibration procedures, long focal length "streak" meteor photome&y and two-station track determination. Meteor44 has been used to analyze data from the 2001.2002 and 2003 MSFC Leonid observational campaigns as well as several lesser showers. The software is interactive and can be demonstrated using data from recent Leonid campaigns.

  17. GPR profiles of Saddle Mountain scoria deposits on Walker Lake Crater tuff ring in Arizona help understanding of geomorphological response to wildland fire

    NASA Astrophysics Data System (ADS)

    Martinez-Hackert, B.; Schwartz, C.; Williams, K.

    2009-05-01

    Walker Lake tuff ring in the San Francisco Volcanic Field, Arizona, experienced a significant forest fire in 1996. Extensive event scale studies suggested a highly increased (by two orders of magnitude) erosion rate both due to raindrop impact and overland flow. However, the 2.3 million year old cone's materials are partially covered by a 15,000-year-old scoria cone deposit from nearby Saddle Mountain. Although previous studies of the geomorphology of Walker Lake crater provided insight into the Saddle Mountain deposit, new studies have actually shown the extent and depth of the deposit on the cone. We present data obtained with ground penetrating radar (GPR) that gives a clearer data set on the depth (4-7m) of the younger deposit in one of the more extensively studied areas. Data were collected along longitudinal and horizontal profiles along the southwestern part of the cone where the deposit is clearly recognizable on the surface and the wild land fire devastation is enormous. Future analysis will shed quantitative light on the effect that the younger, less cohesive materials has on the increased erosion rates in the event scale to decadal scale erosion rates after wildland fire.

  18. Video Meteor Fluxes

    NASA Technical Reports Server (NTRS)

    Campbell-Brown, M. D.; Braid, D.

    2011-01-01

    The flux of meteoroids, or number of meteoroids per unit area per unit time, is critical for calibrating models of meteoroid stream formation and for estimating the hazard to spacecraft from shower and sporadic meteors. Although observations of meteors in the millimetre to centimetre size range are common, flux measurements (particularly for sporadic meteors, which make up the majority of meteoroid flux) are less so. It is necessary to know the collecting area and collection time for a given set of observations, and to correct for observing biases and the sensitivity of the system. Previous measurements of sporadic fluxes are summarized in Figure 1; the values are given as a total number of meteoroids striking the earth in one year to a given limiting mass. The Gr n et al. (1985) flux model is included in the figure for reference. Fluxes for sporadic meteoroids impacting the Earth have been calculated for objects in the centimeter size range using Super-Schmidt observations (Hawkins & Upton, 1958); this study used about 300 meteors, and used only the physical area of overlap of the cameras at 90 km to calculate the flux, corrected for angular speed of meteors, since a large angular speed reduces the maximum brightness of the meteor on the film, and radiant elevation, which takes into account the geometric reduction in flux when the meteors are not perpendicular to the horizontal. They bring up corrections for both partial trails (which tends to increase the collecting area) and incomplete overlap at heights other than 90 km (which tends to decrease it) as effects that will affect the flux, but estimated that the two effects cancelled one another. Halliday et al. (1984) calculated the flux of meteorite-dropping fireballs with fragment masses greater than 50 g, over the physical area of sky accessible to the MORP fireball cameras, counting only observations in clear weather. In the micron size range, LDEF measurements of small craters on spacecraft have been used to

  19. Crater Landslide

    NASA Technical Reports Server (NTRS)

    2006-01-01

    [figure removed for brevity, see original site] Context image for PIA06088 Crater Landslide

    This landslide occurs in an unnamed crater southeast of Millochau Crater.

    Image information: VIS instrument. Latitude -24.4N, Longitude 87.5E. 17 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  20. Cydonia Craters

    NASA Technical Reports Server (NTRS)

    2003-01-01

    [figure removed for brevity, see original site]

    Eroded mesas and secondary craters dot the landscape in this area of the Cydonia Mensae region. The single oval-shaped crater displays a 'butterfly' ejecta pattern, indicating that the crater formed from a low-angle impact.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

    Image information: VIS instrument. Latitude 32.9, Longitude 343.8 East (16.2 West). 19 meter/pixel resolution.

  1. Crater Clouds

    NASA Technical Reports Server (NTRS)

    2006-01-01

    [figure removed for brevity, see original site] Context image for PIA06085 Crater Clouds

    The crater on the right side of this image is affecting the local wind regime. Note the bright line of clouds streaming off the north rim of the crater.

    Image information: VIS instrument. Latitude -78.8N, Longitude 320.0E. 17 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  2. Crater Fill

    NASA Technical Reports Server (NTRS)

    2005-01-01

    [figure removed for brevity, see original site] Context image for PIA03082 Crater Fill

    This VIS image shows part of the floor of an unnamed crater located between the Hellas and Argyre Basins. At some point in time the entire floor of the crater was filled by material. That material is now being eroded away to form the depressions seen in the center and bottom of the image.

    Image information: VIS instrument. Latitude 46.6S, Longitude 5.0E. 17 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  3. Partially-Exhumed Crater in Northern Terra Meridiani: Mosaic of M04-01289, E17-01676, and M21-01646

    NASA Technical Reports Server (NTRS)

    2002-01-01

    MGS MOC Release No. MOC2-316, 8 August 2002 Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) images have shown time and again that the geology and history of Mars is complex. These two pictures show different views of a circular feature in northern Terra Meridiani at 2.3oN, 356.6oW. The first is a mosaic of 3 MOC narrow angle images acquired in August 1999, November 2000, and June 2002. The black area is a gap in coverage resulting from data lost after transmission from Mars to Earth. The second picture is a stereo ('3-D') anaglyph of a portion of the same circular feature. It has been rotated 90o clockwise to show the stereo effect that results from combining the August 1999 image, which was taken while the spacecraft was pointed nadir (straight down) and the June 2002 image, taken with the spacecraft pointing backwards about 16o (i.e., MGS Relay-16 orientation). The anaglyph should be viewed with '3-D' glasses (red in left eye, blue in the right). The circular feature was once an impact crater. The crater was 2.6 km (1.6 mi) across, about 2.6 times larger than the famous Meteor Crater in northern Arizona. Terra Meridiani, like northern Arizona, is a region of vast exposures of layered sedimentary rock. Like the crater in Arizona, this one was formed by a meteor that impacted a layered rock substrate. Later, this crater was filled and completely buried under more than 100 m (more than 327 ft) of additional layered sediment. The sediment hardened to become rock. Later still, the rock was eroded away--by processes unknown (perhaps wind)--to re-expose the buried crater. The crater today remains mostly filled with sediment, its present rim standing only about 40 m (130 ft) above its surroundings.

  4. Palos Crater

    NASA Technical Reports Server (NTRS)

    2002-01-01

    [figure removed for brevity, see original site]

    Palos Crater has been suggested as a future landing site for Mars Missions. This crater has a channel called Tinto Vallis, which enters from the south. This site was suggested as a landing site because it may contain lake deposits. Palos Crater is named in honor of the port city in Spain from which Christopher Columbus sailed on his way to the New World in August of 1492. The floor of Palos Crater appears to be layered in places providing further evidence that this site may in fact have been the location of an ancient lake.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  5. Scaling craters in carbonates: Electron paramagnetic resonance analysis of shock damage

    NASA Technical Reports Server (NTRS)

    Polanskey, Carol A.; Ahrens, Thomas J.

    1994-01-01

    prehistoric shock damage. This is demonstrated by our study of shocked Kaibab limestone from the 49,000-year-old Meteor (Barringer) Crater Arizona.

  6. Exhuming South Polar Crater

    NASA Technical Reports Server (NTRS)

    2004-01-01

    7 February 2004 The large, circular feature in this image is an old meteor impact crater. The crater is larger than the 3 kilometers-wide (1.9 miles-wide) Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image, thus only part of the crater is seen. The bright mesas full of pits and holes--in some areas resembling swiss cheese--are composed of frozen carbon dioxide. In this summertime view, the mesa slopes and pit walls are darkened as sunlight causes some of the ice to sublime away. At one time in the past, the crater shown here may have been completely covered with carbon dioxide ice, but, over time, it has been exhumed as the ice sublimes a little bit more each summer. The crater is located near 86.8oS, 111.6oW. Sunlight illuminates this scene from the upper left.

  7. Abstracts for the International Conference on Asteroids, Comets, Meteors 1991

    NASA Technical Reports Server (NTRS)

    1991-01-01

    Topics addressed include: chemical abundances; asteroidal belt evolution; sources of meteors and meteorites; cometary spectroscopy; gas diffusion; mathematical models; cometary nuclei; cratering records; imaging techniques; cometary composition; asteroid classification; radio telescopes and spectroscopy; magnetic fields; cosmogony; IUE observations; orbital distribution of asteroids, comets, and meteors; solar wind effects; computerized simulation; infrared remote sensing; optical properties; and orbital evolution.

  8. Asteroids, Comets, Meteors 2014

    NASA Astrophysics Data System (ADS)

    Muinonen, K.; Penttilä, A.; Granvik, M.; Virkki, A.; Fedorets, G.; Wilkman, O.; Kohout, T.

    2014-08-01

    Asteroids, Comets, Meteors focuses on the research of small Solar System bodies. Small bodies are the key to understanding the formation and evolution of the Solar System, carrying signals from pre-solar times. Understanding the evolution of the Solar System helps unveil the evolution of extrasolar planetary systems. Societally, small bodies will be important future resources of minerals. The near-Earth population of small bodies continues to pose an impact hazard, whether it be small pieces of falling meteorites or larger asteroids or cometary nuclei capable of causing global environmental effects. The conference series entitled ''Asteroids, Comets, Meteors'' constitutes the leading international series in the field of small Solar System bodies. The first three conferences took place in Uppsala, Sweden in 1983, 1985, and 1989. The conference is now returning to Nordic countries after a quarter of a century. After the Uppsala conferences, the conference has taken place in Flagstaff, Arizona, U.S.A. in 1991, Belgirate, Italy in 1993, Paris, France in 1996, Ithaca, New York, U.S.A. in 1999, in Berlin, Germany in 2002, in Rio de Janeiro, Brazil in 2005, in Baltimore, Maryland, U.S.A. in 2008, and in Niigata, Japan in 2012. ACM in Helsinki, Finland in 2014 will be the 12th conference in the series.

  9. Crater studies: Part A: lunar crater morphometry

    USGS Publications Warehouse

    Pike, Richard J.

    1973-01-01

    Morphometry, the quantitative study of shape, complements the visual observation and photointerpretation in analyzing the most outstanding landforms of the Moon, its craters (refs. 32-1 and 32-2). All three of these interpretative tools, which were developed throughout the long history of telescopic lunar study preceding the Apollo Program, will continue to be applicable to crater analysis until detailed field work becomes possible. Although no large (>17.5 km diameter) craters were examined in situ on any of the Apollo landings, the photographs acquired from the command modules will markedly strengthen results of less direct investigations of the craters. For morphometry, the most useful materials are the orbital metric and panoramic photographs from the final three Apollo missions. These photographs permit preparation of contour maps, topographic profiles, and other numerical data that accurately portray for the first time the surface geometry of lunar craters of all sizes. Interpretations of craters no longer need be compromised by inadequate topographic data. In the pre-Apollo era, hypotheses for the genesis of lunar craters usually were constructed without any numerical descriptive data. Such speculations will have little credibility unless supported by accurate, quantitative data, especially those generated from Apollo orbital photographs. This paper presents a general study of the surface geometry of 25 far-side craters and a more detailed study of rim-crest evenness for 15 near-side and far-side craters. Analysis of this preliminary sample of Apollo 15 and 17 data, which includes craters between 1.5 and 275 km in diameter, suggests that most genetic interpretations of craters made from pre-Apollo topographic measurements may require no drastic revision. All measurements were made from topographic profiles generated on a stereoplotter at the Photogrammetric Unit of the U.S. Geological Survey, Center of Astrogeology, Flagstaff, Arizona.

  10. The history of meteors and meteor showers

    NASA Astrophysics Data System (ADS)

    Hughes, David W.

    The history of meteors and meteor showers can effectively start with the work of Edmond Halley who overcome the Aristotelean view of meteors as being an upper atmospheric phenomenon and introduced their extraterrestrial nature. Halley also estimated their height and velocity. The observations of the Leonids in 1799, 1833 and 1866 established meteoroids as cometary debris. Two red herrings were caught — fixed radiants and hyperbolic velocities. But the 1890 to 1950 period with two-station meteor photography, meteor spectroscopy and the radar detection of meteors saw the subject well established.

  11. Meteor trajectory estimation from radio meteor observations

    NASA Astrophysics Data System (ADS)

    Kákona, J.

    2016-01-01

    Radio meteor observation techniques are generally accepted as meteor counting methods useful mainly for meteor flux detection. Due to the technical progress in radio engineering and electronics a construction of a radio meteor detection network with software defined receivers has become possible. These receivers could be precisely time synchronized and could obtain data which provide us with more information than just the meteor count. We present a technique which is able to compute a meteor trajectory from the data recorded by multiple radio stations.

  12. Evidence for Recent Liquid Water on Mars: Channeled Aprons in a Small Crater within Newton Crater

    NASA Technical Reports Server (NTRS)

    2000-01-01

    [figure removed for brevity, see original site]

    Newton Crater is a large basin formed by an asteroid impact that probably occurred more than 3 billion years ago. It is approximately 287 kilometers (178 miles) across. The picture shown here (top) highlights the north wall of a specific, smaller crater located in the southwestern quarter of Newton Crater (above). The crater of interest was also formed by an impact; it is about 7 km (4.4 mi) across, which is about 7 times bigger than the famous Meteor Crater in northern Arizona in North America.

    The north wall of the small crater has many narrow gullies eroded into it. These are hypothesized to have been formed by flowing water and debris flows. Debris transported with the water created lobed and finger-like deposits at the base of the crater wall where it intersects the floor (bottom center top image). Many of the finger-like deposits have small channels indicating that a liquid--most likely water--flowed in these areas. Hundreds of individual water and debris flow events might have occurred to create the scene shown here. Each outburst of water from higher upon the crater slopes would have constituted a competition between evaporation, freezing, and gravity.

    The individual deposits at the ends of channels in this MOC image mosaic were used to get a rough estimate of the minimum amount of water that might be involved in each flow event. This is done first by assuming that the deposits are like debris flows on Earth. In a debris flow, no less than about 10% (and no more than 30%) of their volume is water. Second, the volume of an apron deposit is estimated by measuring the area covered in the MOC image and multiplying it by a conservative estimate of thickness, 2 meters (6.5 feet). For a flow containing only 10% water, these estimates conservatively suggest that about 2.5 million liters (660,000 gallons) of water are involved in each event; this is enough to fill about 7 community-sized swimming pools or

  13. Fresh, Rayed Impact Crater

    NASA Technical Reports Server (NTRS)

    2003-01-01

    MGS MOC Release No. MOC2-416, 9 July 2003

    This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a fresh, young meteor impact crater on the martian surface. It is less than 400 meters (less than 400 yards) across. While there is no way to know the exact age of this or any other martian surface feature, the rays are very well preserved. On a planet where wind can modify surface features at the present time, a crater with rayed ejecta patterns must be very young indeed. Despite its apparent youth, the crater could still be many hundreds of thousands, if not several million, of years old. This impact scar is located within the much larger Crommelin Crater, near 5.6oN, 10.0oW. Sunlight illuminates the scene from the left.

  14. Craters and Layers

    NASA Technical Reports Server (NTRS)

    2006-01-01

    11 March 2006 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows some typical relations between impact craters and light-toned, layered rock on Mars. The larger circular feature at the north (top) end of the image marks the location of a filled, buried crater on intermountain terrain north of Hellas Planitia. The larger crater at the southeast (lower right) corner formed by meteor impact into the layered material in which the buried crater is encased. The layered rock, in this case, has a light tone similar to the sedimentary rocks being explored by the Mars Exploration Rover, Opportunity, thousands of kilometers away in Sinus Meridiani.

    Location near: 24.9oS, 299.3oW Image width: 3 km (1.9 mi) Illumination from: upper left Season: Southern Summer

  15. Crater Copernicus

    NASA Technical Reports Server (NTRS)

    1999-01-01

    HUBBLE SHOOTS THE MOON in a change of venue from peering at the distant universe, NASA's Hubble Space Telescope has taken a look at Earth's closest neighbor in space, the Moon. Hubble was aimed at one of the Moon's most dramatic and photogenic targets, the 58 mile-wide (93 km) impact crater Copernicus. The image was taken while the Space Telescope Imaging Spectrograph(STIS) was aimed at a different part of the moon to measure the colors of sunlight reflected off the Moon. Hubble cannot look at the Sun directly and so must use reflected light to make measurements of the Sun's spectrum. Once calibrated by measuring the Sun's spectrum, the STIS can be used to study how the planets both absorb and reflect sunlight.(upper left)The Moon is so close to Earth that Hubble would need to take a mosaic of 130 pictures to cover the entire disk. This ground-based picture from Lick Observatory shows the area covered in Hubble's photomosaic with the WideField Planetary Camera 2..(center)Hubble's crisp bird's-eye view clearly shows the ray pattern of bright dust ejected out of the crater over one billion years ago, when an asteroid larger than a mile across slammed into the Moon. Hubble can resolve features as small as 600 feet across in the terraced walls of the crater, and the hummock-like blanket of material blasted out by the meteor impact.(lower right)A close-up view of Copernicus' terraced walls. Hubble can resolve features as small as 280 feet across.

  16. Meteor Beliefs Project: ``Year of Meteors''

    NASA Astrophysics Data System (ADS)

    McBeath, Alastair; Drobnock, George J.; Gheorghe, Andrei Dorian

    2011-10-01

    We present a discussion linking ideas from a modern music album by Laura Veirs back to a turbulent time in American history 150 years ago, which inspired poet Walt Whitman to compose his poem "Year of Meteors", and the meteor beliefs of the period around 1859-1860, when collection of facts was giving way to analyses and theoretical explanations in meteor science.

  17. Wind Streak and Crater

    NASA Technical Reports Server (NTRS)

    2004-01-01

    23 February 2004 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a wind streak developed in the lee of a meteor impact crater in western Daedalia Planum. The dominant winds responsible for the streak blew from the bottom/lower right (southeast). The image is located near 9.9oS, 144.9oW. Sunlight illuminates the scene from the lower left; the picture covers an area 3 km (1.9 mi) wide.

  18. Arkhangelsky Crater

    NASA Technical Reports Server (NTRS)

    2003-01-01

    [figure removed for brevity, see original site]

    Released 12 September 2003

    Arkhangelsky crater is just to the northeast of the giant Argyre impact basin in the southern hemisphere of Mars. This THEMIS visible image shows the floor of this crater with a few dark barchan dunes. Dunes form when wind blows sand across a surface. The barchan dunes shown here form when there isn't a whole lot of sand to start with. If there were, other dune forms would be visible.

    Image information: VIS instrument. Latitude -41.2, Longitude 334.9 East (25.1 West). 19 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  19. Gusev Crater

    NASA Technical Reports Server (NTRS)

    2003-01-01

    [figure removed for brevity, see original site]

    Released 25 July 2003

    Wrinkle ridges deform the plains in the bottom of Gusev crater, destination of the MER 'Spirit' rover. The plains were likely created from a flood basalt with ridges forming where there were compressional forces. Dark wind streaks come together to form a dark spot at the bottom of the image where the wind has removed a thin layer of bright dust off a dark surface. On the left side of the image a portion of a lobe of material is visible, which may have resulted from a mud or debris flow. This feature was recently identified by the THEMIS team and may represent the most recent deposit in the crater involving water.

    Image information: VIS instrument. Latitude -13.9, Longitude 175.4 East (184.6 West). 19 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  20. Freedom Crater

    NASA Technical Reports Server (NTRS)

    2003-01-01

    [figure removed for brevity, see original site]

    Freedom crater, located in Acidalia Planitia, exhibits a concentric ring pattern in its interior, suggesting that there has been some movement of these materials towards the center of the crater. Slumping towards the center may have been caused by the presence of ground ice mixed in with the sediments. The origin for the scarps on the western edge of the interior deposit is unknown.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

    Image information: VIS instrument. Latitude 43.3, Longitude 351.3 East (8.7 West). 19 meter/pixel resolution.

  1. The Meteor Meter.

    ERIC Educational Resources Information Center

    Eggensperger, Martin B.

    2000-01-01

    Introduces the Meteor Scatter Project (MSP) in which high school students build an automated meteor observatory and learn to monitor meteor activity. Involves students in activities such as radio frequency survey, antenna design, antenna construction, manual meteor counts, and computer board configuration and installation. (YDS)

  2. Crater Rim

    NASA Technical Reports Server (NTRS)

    2003-01-01

    [figure removed for brevity, see original site]

    The late afternoon sun casts a shadow over a 700 meter-high rim of Huygens Crater.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

    Image information: VIS instrument. Latitude -15.2, Longitude 51.6 East (308.4 West). 19 meter/pixel resolution.

  3. Becquerel Crater

    NASA Technical Reports Server (NTRS)

    2006-01-01

    [figure removed for brevity, see original site] Context image for PIA03676 Linear Clouds

    This interesting deposit is located on the floor of Becquerel Crater.

    Image information: VIS instrument. Latitude 21.3N, Longitude 352.2E. 18 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  4. Impact Crater

    NASA Technical Reports Server (NTRS)

    2002-01-01

    [figure removed for brevity, see original site]

    The layering of material observed at the bottom of this impact crater suggests multiple depositional and erosional episodes in a changing environment.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  5. SEC Vidicon spectra of Geminid meteors, 1972

    NASA Technical Reports Server (NTRS)

    Millman, P. M.; Clifton, K. S.

    1975-01-01

    The SEC Vidicon, a low light level closed circuit television system, was used to obtain 137 spectrographic records of meteors at Mt. Hopkins, Arizona, during the Geminid meteor shower in December 1972. Seven of the best Geminid meteor spectra are studied here in detail. The near infrared, out to wavelengths near 9000 A, is recorded for the first time for Geminids. The spectra, in general, exhibit the elements previously found in photographic records of this shower but show a surprising frequency of occurrence of the forbidden green line of O I at 5577 A. This line is normally absent from meteors moving as slowly as the Geminids (36 km/sec) and its presence in these records may be due to the added sensitivity available with the SEC Vidicon. The average green line duration in Geminid meteors with a luminosity near zero absolute visual magnitude is 0.73 sec at a mean height of 95 km, 11 km lower than the green line peak in Perseid meteors of the same luminosity.

  6. Energy Dissipation Mechanisms in 2D Meteor Impacts

    NASA Astrophysics Data System (ADS)

    Lane, Andrew; Daniels, Karen E.; Utter, Brian; Behringer, R. P.

    2003-11-01

    The morphology of meteor craters has historically been studied via static analysis, after the fact, of what are highly dynamic impact events. As such, there are long-standing questions about the means through which a meteor comes to rest and forms a crater. Using high speed video analysis on a 2D lab-scale system, we characterize the dynamics of a "meteor" impacting on a granular bed. In this case, the particles are made of a photoelastic material, so that it is possible to measure the instantaneous elastic energy stored in the bed. To understand the energy dissipation mechanisms involved in slowing the meteor, we track the kinetic, potential, and elastic energies associated with individual grains. Two initial and tentative findings from this work are: 1) Damped oscillations occur as the energy is dissipated within the granular material; and 2) The angle of impact strongly influences the dynamics and final state.

  7. Quadrantid Meteor, 2013

    NASA Video Gallery

    An allsky camera in New Mexico captured a brief video of this Quadrantid fireball meteor on Jan. 3, 2013 at 2:04 a.m. EST. The Quadrantid meteor shower occurs each January and derives its name from...

  8. Catalogue of representative meteor spectra

    NASA Astrophysics Data System (ADS)

    Vojáček, V.; Borovička, J.; Koten, P.; Spurný, P.; Štork, R.

    2016-01-01

    We present a library of low-resolution meteor spectra that includes sporadic meteors, members of minor meteor showers, and major meteor showers. These meteors are in the magnitude range from +2 to ‑3, corresponding to meteoroid sizes from 1 mm to10 mm. This catalogue is available online at the CDS for those interested in video meteor spectra.

  9. Northern Plains 'Crater'

    NASA Technical Reports Server (NTRS)

    2004-01-01

    10 December 2004 The lower left (southwest) corner of this Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows the location of a somewhat filled and buried meteor impact crater on the northern plains of Mars. The dark dots are boulders. A portion of a similar feature is seen in the upper right (northeast) corner of the image. This picture, showing landforms (including the odd mound north/northeast of the crater) that are typical of the martian northern lowland plains, was obtained as part of the MGS MOC effort to support the search for a landing site for the Phoenix Mars Scout lander. Phoenix will launch in 2007 and land on the northern plains in 2008. This image is located near 68.0oN, 227.4oW, and covers an area approximately 3 km (1.9 mi) wide. The scene is illuminated by sunlight from the lower left.

  10. Iturralde Crater, Bolivia

    NASA Technical Reports Server (NTRS)

    2002-01-01

    NASA scientists will venture into an isolated part of the Bolivian Amazon to try and uncover the origin of a 5 mile (8 kilometer) diameter crater there known as the Iturralde Crater. Traveling to this inhospitable forest setting, the Iturralde Crater Expedition 2002 will seek to determine if the unusual circular crater was created by a meteor or comet. Organized by Dr. Peter Wasilewski of NASA's Goddard Space Flight Center, Greenbelt, Md., the Iturralde Crater Expedition 2002 will be led by Dr. Tim Killeen of Conservation International, which is based in Bolivia. Killeen will be assisted by Dr. Compton Tucker of Goddard. The team intends to collect and analyze rocks and soil, look for glass particles that develop from meteor impacts and study magnetic properties in the area to determine if the Iturralde site was indeed created by a meteor.

    This image was acquired on June 29, 2001 by the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on NASA's Terra satellite. With its 14 spectral bands from the visible to the thermal infrared wavelength region, and its high spatial resolution of 15 to 90 meters (about 50 to 300 feet), ASTER will image Earth for the next 6 years to map and monitor the changing surface of our planet.

    ASTER is one of five Earth-observing instruments launched December 18, 1999, on NASA's Terra satellite. The instrument was built by Japan's Ministry of Economy, Trade and Industry. A joint U.S./Japan science team is responsible for validation and calibration of the instrument and the data products.

    The broad spectral coverage and high spectral resolution of ASTER will provide scientists in numerous disciplines with critical information for surface mapping, and monitoring dynamic conditions and temporal change. Example applications are: monitoring glacial advances and retreats; monitoring potentially active volcanoes; identifying crop stress; determining cloud morphology and physical properties; wetlands evaluation

  11. Impact Crater with Peak

    NASA Technical Reports Server (NTRS)

    2002-01-01

    (Released 14 June 2002) The Science This THEMIS visible image shows a classic example of a martian impact crater with a central peak. Central peaks are common in large, fresh craters on both Mars and the Moon. This peak formed during the extremely high-energy impact cratering event. In many martian craters the central peak has been either eroded or buried by later sedimentary processes, so the presence of a peak in this crater indicates that the crater is relatively young and has experienced little degradation. Observations of large craters on the Earth and the Moon, as well as computer modeling of the impact process, show that the central peak contains material brought from deep beneath the surface. The material exposed in these peaks will provide an excellent opportunity to study the composition of the martian interior using THEMIS multi-spectral infrared observations. The ejecta material around the crater can is well preserved, again indicating relatively little modification of this landform since its initial creation. The inner walls of this approximately 18 km diameter crater show complex slumping that likely occurred during the impact event. Since that time there has been some downslope movement of material to form the small chutes and gullies that can be seen on the inner crater wall. Small (50-100 m) mega-ripples composed of mobile material can be seen on the floor of the crater. Much of this material may have come from the walls of the crater itself, or may have been blown into the crater by the wind. The Story When a meteor smacked into the surface of Mars with extremely high energy, pow! Not only did it punch an 11-mile-wide crater in the smoother terrain, it created a central peak in the middle of the crater. This peak forms kind of on the 'rebound.' You can see this same effect if you drop a single drop of milk into a glass of milk. With craters, in the heat and fury of the impact, some of the land material can even liquefy. Central peaks like the one

  12. Apparatus for photographing meteors

    NASA Technical Reports Server (NTRS)

    Harvey, G. A. (Inventor)

    1973-01-01

    Apparatus for photographing meteors in a selected area of the sky is described. A photomultiplier is pointed in the direction of the area. When a meteor passes through the area the signal output of the photomultiplier increases. Means are provided that activate a camera, pointed at the area, in response to an increased signal from the photomultiplier. Hence, the camera photographs the selected are only while meteors are likely to be passing through the area.

  13. Antoniadi Crater

    NASA Technical Reports Server (NTRS)

    2005-01-01

    [figure removed for brevity, see original site]

    The THEMIS VIS camera is capable of capturing color images of the Martian surface using five different color filters. In this mode of operation, the spatial resolution and coverage of the image must be reduced to accommodate the additional data volume produced from using multiple filters. To make a color image, three of the five filter images (each in grayscale) are selected. Each is contrast enhanced and then converted to a red, green, or blue intensity image. These three images are then combined to produce a full color, single image. Because the THEMIS color filters don't span the full range of colors seen by the human eye, a color THEMIS image does not represent true color. Also, because each single-filter image is contrast enhanced before inclusion in the three-color image, the apparent color variation of the scene is exaggerated. Nevertheless, the color variation that does appear is representative of some change in color, however subtle, in the actual scene. Note that the long edges of THEMIS color images typically contain color artifacts that do not represent surface variation.

    This false color image shows part of the floor of Antoniadi Crater. This image was collected during the Northern Spring season.

    Image information: VIS instrument. Latitude 37, Longitude 62.6 East (297.4 West). 35 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science

  14. Rampart Crater

    NASA Technical Reports Server (NTRS)

    2004-01-01

    [figure removed for brevity, see original site]

    Released 20 May 2004 This image of a rampart crater was acquired Dec. 6, 2002, during northern summer.

    The THEMIS VIS camera is capable of capturing color images of the martian surface using its five different color filters. In this mode of operation, the spatial resolution and coverage of the image must be reduced to accommodate the additional data volume produced from the use of multiple filters. To make a color image, three of the five filter images (each in grayscale) are selected. Each is contrast enhanced and then converted to a red, green, or blue intensity image. These three images are then combined to produce a full color, single image. Because the THEMIS color filters don't span the full range of colors seen by the human eye, a color THEMIS image does not represent true color. Also, because each single-filter image is contrast enhanced before inclusion in the three-color image, the apparent color variation of the scene is exaggerated. Nevertheless, the color variation that does appear is representative of some change in color, however subtle, in the actual scene. Note that the long edges of THEMIS color images typically contain color artifacts that do not represent surface variation.

    Image information: VIS instrument. Latitude 28.4, Longitude 319.2 East (40.8 West). 38 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The

  15. Moreux Crater

    NASA Technical Reports Server (NTRS)

    2004-01-01

    [figure removed for brevity, see original site]

    Released 27 May 2004 This image of material entering Moreux Crater from the rim area was acquired March 17, 2003, during northern summer.

    The THEMIS VIS camera is capable of capturing color images of the martian surface using its five different color filters. In this mode of operation, the spatial resolution and coverage of the image must be reduced to accommodate the additional data volume produced from the use of multiple filters. To make a color image, three of the five filter images (each in grayscale) are selected. Each is contrast enhanced and then converted to a red, green, or blue intensity image. These three images are then combined to produce a full color, single image. Because the THEMIS color filters don't span the full range of colors seen by the human eye, a color THEMIS image does not represent true color. Also, because each single-filter image is contrast enhanced before inclusion in the three-color image, the apparent color variation of the scene is exaggerated. Nevertheless, the color variation that does appear is representative of some change in color, however subtle, in the actual scene. Note that the long edges of THEMIS color images typically contain color artifacts that do not represent surface variation.

    Image information: VIS instrument. Latitude 41.1, Longitude 44.1 East (315.9 West). 38 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of

  16. Crater Ejecta

    NASA Technical Reports Server (NTRS)

    2004-01-01

    [figure removed for brevity, see original site]

    Released 21 May 2004 This image of ejecta (top-left) from a rampart crater was acquired March 3, 2003, during northern summer.

    The THEMIS VIS camera is capable of capturing color images of the martian surface using its five different color filters. In this mode of operation, the spatial resolution and coverage of the image must be reduced to accommodate the additional data volume produced from the use of multiple filters. To make a color image, three of the five filter images (each in grayscale) are selected. Each is contrast enhanced and then converted to a red, green, or blue intensity image. These three images are then combined to produce a full color, single image. Because the THEMIS color filters don't span the full range of colors seen by the human eye, a color THEMIS image does not represent true color. Also, because each single-filter image is contrast enhanced before inclusion in the three-color image, the apparent color variation of the scene is exaggerated. Nevertheless, the color variation that does appear is representative of some change in color, however subtle, in the actual scene. Note that the long edges of THEMIS color images typically contain color artifacts that do not represent surface variation.

    Image information: VIS instrument. Latitude 25.9, Longitude 322 East (38 West). 38 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science

  17. Atmospheric heating of meteors.

    NASA Technical Reports Server (NTRS)

    Harwell, K. E.; Mccay, T. D.; Best, J. T.

    1972-01-01

    A theoretical model of the radiating metallic gas produced about an iron meteor entering the earth's atmosphere is discussed. Numerical results are presented for a 0.1 cm diameter iron meteor traveling at 15 km/sec at an altitude of 100 km above the earth. It is shown that collisions between the expanding iron gas and the air molecules produce a radiating gas shell a few meters thick which is located many meters ahead of the meteor core. Temperature, pressure, and density distributions are presented as functions of radial distance and angle for several initial meteor conditions.

  18. Practical Meteor Stream Forecasting

    NASA Technical Reports Server (NTRS)

    Cooke, William J.; Suggs, Robert M.

    2003-01-01

    Inspired by the recent Leonid meteor storms, researchers have made great strides in our ability to predict enhanced meteor activity. However, the necessary calibration of the meteor stream models with Earth-based ZHRs (Zenith Hourly Rates) has placed emphasis on the terran observer and meteor activity predictions are published in such a manner to reflect this emphasis. As a consequence, many predictions are often unusable by the satellite community, which has the most at stake and the greatest interest in meteor forecasting. This paper suggests that stream modelers need to pay more attention to the needs of this community and publish not just durations and times of maxima for Earth, but everything needed to characterize the meteor stream in and out of the plane of the ecliptic, which, at a minimum, consists of the location of maximum stream density (ZHR) and the functional form of the density decay with distance from this point. It is also suggested that some of the terminology associated with meteor showers may need to be more strictly defined in order to eliminate the perception of crying wolf by meteor scientists. An outburst is especially problematic, as it usually denotes an enhancement by a factor of 2 or more to researchers, but conveys the notion of a sky filled with meteors to satellite operators and the public. Experience has also taught that predicted ZHRs often lead to public disappointment, as these values vastly overestimate what is seen.

  19. Rare Double Quadrantid Meteor Sighting

    NASA Video Gallery

    The wide-field meteor camera at NASA's Marshall Space Flight Center recorded these two simultaneous Quadrantid meteors on Jan. 4 at approximately 5 a.m. EST. Moving at 92,000 mph, the meteors flash...

  20. Terra Cimmeria Crater Landslide

    NASA Technical Reports Server (NTRS)

    2005-01-01

    [figure removed for brevity, see original site]

    The landslide in this VIS image is located inside an impact crater in the Terra Cimmeria region of Mars. The unnamed crater hosting this image is just east of Molesworth Crater.

    Image information: VIS instrument. Latitude -27.7, Longitude 152 East (208 West). 19 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  1. Isidis Crater Landslide

    NASA Technical Reports Server (NTRS)

    2005-01-01

    [figure removed for brevity, see original site]

    The landslide in this VIS image is located inside an impact crater located south of the Isidis Planitia region of Mars. As with the previous unnamed crater landslide, this one formed due to slope failure of the inner crater rim.

    Image information: VIS instrument. Latitude -2.9, Longitude 90.8 East (269.2 West). 19 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  2. Mare Chromium Crater

    NASA Technical Reports Server (NTRS)

    2004-01-01

    [figure removed for brevity, see original site]

    This crater, located in Mare Chromium, shows evidence of exterior modification, with little interior modification. While the rim is still visible, the ejecta blanket has been removed or covered. There is some material at the bottom of the crater, but the interior retains the bowl shape from the initial formation of the crater.

    Image information: VIS instrument. Latitude -34.4, Longitude 174.4 East (185.6 West). 19 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  3. Cratering mechanics

    NASA Technical Reports Server (NTRS)

    Ivanov, B. A.

    1986-01-01

    Main concepts and theoretical models which are used for studying the mechanics of cratering are discussed. Numerical two-dimensional calculations are made of explosions near a surface and high-speed impact. Models are given for the motion of a medium during cratering. Data from laboratory modeling are given. The effect of gravitational force and scales of cratering phenomena is analyzed.

  4. Rayed Gratteri Crater

    NASA Technical Reports Server (NTRS)

    2006-01-01

    [figure removed for brevity, see original site] Click on image for larger version

    This HiRISE image covers the western portion of the primary cavity of Gratteri crater situated in the Memnonia Fossae region. Gratteri crater is one of five definitive large rayed craters on Mars. Gratteri crater has a diameter of approximately 6.9 kilometers. Crater rays are long, linear features formed from the high-velocity ejection of blocks of material that re-impact the surface in linear clusters or chains that appear to emanate from the main or primary cavity. Such craters have been long recognized as the 'brightest' and 'freshest' craters on the Moon. However, Martian rays differ from lunar rays in that they are not 'bright,' but best recognized by their thermal signature (at night) in 100 meter/pixel THEMIS thermal infrared images. The HiRISE image shows that Gratteri crater has well-developed and sharp crater morphologic features with no discernable superimposed impact craters. The HiRISE sub-image shows that this is true for the ejecta and crater floor up to the full resolution of the image. Massive slumped blocks of materials on the crater floor and the 'spur and gully' morphology with the crater wall may suggest that the subsurface in this area may be thick and homogenous. Gratteri crater's ejecta blanket (as seen in THEMIS images) can be described as 'fluidized,' which may be suggestive of the presence of ground-ice that may have helped to 'liquefy' the ejecta as it was deposited near the crater. Gratteri's ejecta can be observed to have flowed in and around obstacles including an older, degraded crater lying immediately to the SW of Gratteri's primary cavity.

    Image PSP_001367_1620 was taken by the High Resolution Imaging Science Experiment (HiRISE) camera onboard the Mars Reconnaissance Orbiter spacecraft on November 10, 2006. The complete image is centered at -17.7 degrees latitude, 199.9 degrees East longitude. The range to the target site was 257.1 km

  5. The Newcastle meteor radar

    NASA Technical Reports Server (NTRS)

    Keay, Colin

    1987-01-01

    A brief history and development of the Newcastle Meteor Radar system is given. Also described are its geographical coordinates and its method of operation. The initial objective when the project was commenced was to develop an entirely digital analyzer capable of recognizing meteor echo signals and recording as many of their parameters as possible. This objective was achieved.

  6. Meteor Beliefs Project: Introduction

    NASA Astrophysics Data System (ADS)

    McBeath, A.; Gheorghe, A. D.

    2003-05-01

    A new project to investigate beliefs in meteors and meteoric phenomena in past and present times using chiefly folklore, mythology, prose and poetic literature, is described. Some initial examples are given, along with a bibliography of relevant items already in print in IMO publications.

  7. Layered Rocks in Crater

    NASA Technical Reports Server (NTRS)

    2004-01-01

    19 June 2004 Exposures of layered, sedimentary rock are common on Mars. From the rock outcrops examined by the Mars Exploration Rover, Opportunity, in Meridiani Planum to the sequence in Gale Crater's central mound that is twice the thickness of of the sedimentary rocks exposed by Arizona's Grand Canyon, Mars presents a world of sediment to study. This unusual example, imaged by the Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC), shows eroded layer outcrops in a crater in Terra Tyrrhena near 15.4oS, 270.5oW. Sedimentary rocks provide a record of past climates and events. Perhaps someday the story told by the rocks in this image will be known via careful field work. The image covers an area about 3 km (1.9 mi) wide and is illuminated by sunlight from the left.

  8. Dynamics of meteor streams

    NASA Technical Reports Server (NTRS)

    Babadjanov, P. B.; Obrubov, Yu. U.

    1987-01-01

    The overwhelming majority of meteor streams are generally assumed to be formed due to the decay of comets. The most effective process of the release of solid particles from a cometary nucleus is their ejection by sublimating gases when the comet approaches the Sun. The results of investigation of the Geminids and Quadrantids meteor stream evolution show that under the influence of planetary perturbations, the stream may originally be flat but then thicken depending on the variation range of orbital inclinations. Eventually, due to planetary perturbations, a meteor stream may take such a shape as to cause the start of several active showers at different solar longitudes.

  9. Meteors, comets, and millennialism.

    NASA Astrophysics Data System (ADS)

    McBeath, A.

    1999-12-01

    An overview of meteoric and cometary activity between circa 250 BC and circa 1600 AD is discussed with especial regard to the inclusion of meteoric imagery in Christian religious texts. Evidence is presented to suggest meteorite images played a leading role in the creation of millennial fears among adherents of the early medieval Church in Europe, which fears still persist into modern times, but which may have their origins in Mesopotamia circa 2200 BC. An extended discussion of meteoric imagery in Christian writings is also presented.

  10. Minor meteor shower activity

    NASA Astrophysics Data System (ADS)

    Rendtel, J.

    2016-01-01

    Video meteor observations provide us with data to analyze structures in minor meteor showers or weak features in flux profiles. Samples obtained independently by other techniques allow to calibrate the data sets and to improve the confidence of results as demonstrated with a few results. Both, the confirmation of events predicted by model calculation and the input of observational data to improve the modelling results may help to better understand meteoroid stream evolution processes. Furthermore, calibrated data series can be used for studies of the long-term evolution of meteor shower activity.

  11. Optical electronics for meteor observations

    NASA Technical Reports Server (NTRS)

    Shafiev, R. I.; Mukhamednazarov, S.; Atamas, I. A.

    1987-01-01

    Spectral observations of meteors have been carried out for several years using an optical electronics facility. Interest has centered on faint meteors and their trails in the period of intensive meteor showers. Over 800 meteors were registered during the observation period, with spectrograms obtained for 170 of these. A total of 86 meteors were photographed from two sites and for 25 of these spectrograms of the meteors as well as their trails were obtained. All meteors have undergone routine processing in order to determine atmospheric characteristics. Results are discussed.

  12. Current trends in meteor spectroscopy

    NASA Technical Reports Server (NTRS)

    Millman, P. M.

    1982-01-01

    The history of progress over more than a century in meteor spectroscopy is summarized. The observational data were originally visual records, but in the beginning of the 20th century photography of meteor spectra was undertaken. In the forties, 60 meteor spectra were photographed. Interest in the upper atmosphere led to the development of more efficient meteor cameras which employ replica gratings, and electronic image intensification systems recordings on video tape which resulted in the availability of several thousand meteor spectra.

  13. Meteor Beliefs Project: Musical Meteors, meteoric imagery as used in near-contemporary song lyrics

    NASA Astrophysics Data System (ADS)

    McBeath, Alastair; Gheorghe, Andrei Dorian

    2010-01-01

    Items collected from contemporary song lyrics featuring meteoric imagery, or inspired by meteors, are given, with some discussion. While not a major part of the Meteor Beliefs Project, there are points of interest in how such usage may become passed into popular beliefs about meteors.

  14. Landslide in a Crater

    NASA Technical Reports Server (NTRS)

    2005-01-01

    [figure removed for brevity, see original site]

    The landslide in this VIS image is located inside an impact crater in the Elysium region of Mars. The unnamed crater is located at the margin of the volcanic flows from the Elysium Mons complex.

    Image information: VIS instrument. Latitude 1.2, Longitude 134 East (226 West). 19 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  15. Holden Crater Delta

    NASA Technical Reports Server (NTRS)

    2006-01-01

    [figure removed for brevity, see original site] Context image for PIA03694 Holden Crater Delta

    This fan-shaped delta deposit is located in Holden Crater.

    Image information: VIS instrument. Latitude -27.3N, Longitude 324.5E. 17 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  16. Bizarre Crater Mound

    NASA Technical Reports Server (NTRS)

    2003-01-01

    [figure removed for brevity, see original site]

    Released 5 June 2003

    The height of the interior mound of sediment inside this crater exceeds the crater rim heights by 900 meters (3,000 ft). This is a confounding problem. How does all this material get inside this crater and actually rise higher than its holding chamber? What is this material? Where did it come from? Why is it still here? It is exactly these kinds of enigmas that makes Mars so very interesting.

    Image information: VIS instrument. Latitude 12.2, Longitude 26.3 East (333.7 West). 19 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  17. Gale Crater Mound

    NASA Technical Reports Server (NTRS)

    2003-01-01

    [figure removed for brevity, see original site]

    The eroded, layered deposit in Gale Crater is a mound of material rising 3 km above the crater floor. It has been sculpted by wind and possibly water to produce the dramatic landforms seen today. The origin of the sedimentary material that composes the mound remains a contested issue: was it produced from sedimentation in an ancient crater lake or by airfall onto dry land?

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

    Image information: VIS instrument. Latitude -5.1, Longitude 137.5 East (222.5 West). 19 meter/pixel resolution.

  18. Proctor Crater Dunes

    NASA Technical Reports Server (NTRS)

    2002-01-01

    [figure removed for brevity, see original site]

    This image, located near 30E and 47.5S, displays sand dunes within Proctor Crater. These dunes are composed of basaltic sand that has collected in the bottom of the crater. The topographic depression of the crater forms a sand trap that prevents the sand from escaping. Dune fields are common in the bottoms of craters on Mars and appear as dark splotches that lean up against the downwind walls of the craters. Dunes are useful for studying both the geology and meteorology of Mars. The sand forms by erosion of larger rocks, but it is unclear when and where this erosion took place on Mars or how such large volumes of sand could be formed. The dunes also indicate the local wind directions by their morphology. In this case, there are few clear slipfaces that would indicate the downwind direction. The crests of the dunes also typically run north-south in the image. This dune form indicates that there are probably two prevailing wind directions that run east and west (left to right and right to left).

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project

  19. Meteor project --- AMOS Cam

    NASA Astrophysics Data System (ADS)

    Tóth, J.; Kornoš, L.; Zigo, P.; Gajdoš, Š.; Kalmančok, D.; Šimon, J.; Buček, M.; Galád, A.; Ďuriš, F.

    2014-07-01

    Slovak Video Meteor Network (SVMN) is a project of Comenius University in Bratislava for continuous monitoring of meteor activity [1] over Slovakia. The network is based on AMOS (All-sky Meteor Orbit System) Cameras [2], which astrometric precision was calibrated using several commonly observed fireballs within European Fireball Network [3]. The field of view of the AMOS is 180° × 140° and the output digital resolution 1280 × 960 px with the frame rate of 15 f/s. Limiting sensitivity is +5.5 mag for stellar objects and about +4 mag for moving objects. The whole system is protected by outer and inner housing and monitoring by detectors of temperature, rain and illumination of the sky. The system is portable and suitable for expeditions from the ground or research planes. The AMOS cameras are working at four locations (SVMN) at present: AGO Modra, Arboretum T. Mlyňany, Kysucké Nové Mesto Obs. and Važec stations. The operation of cameras is semi-automatic and needs electric power and internet connection. The standard astrometric error is within an interval of 0.03--0.05 deg resulting in several tens or hundreds of meters for meteor atmospheric trajectory determination. The internal precision of the AMOS cameras is even better, especially when the precise all-sky reduction described in [4] is used. The first prototype has been working at the AGO Modra Observatory since 2007. Each AMOS camera records about 10 000 meteors per year as well as about 50 transient luminous events (sprites, elves) in Central Europe sky conditions. The results from the observational expedition on Tenerife and La Palma (Canary Islands 2014) showed higher efficiency of AMOS cameras at high altitudes and dark sites. The analyses of selected meteor streams (SPE, ACO, Lyrids and others) from AMOS cameras will be presented.

  20. Television meteor observations in INASAN

    NASA Astrophysics Data System (ADS)

    Kartashova, Anna

    2013-01-01

    The results of TV observations of meteors during the period 18 July-19 August (activity period of the Perseid meteor shower) in 2011 and 2012 are presented. The wide field-of-view cameras "PatrolCa" were used for the observations. Observations were carried out by the single-station as well as the double-station method. The double-station observations were aimed at determining the individual orbits of the observed meteors. The principle of Index Meteor Activity (IMA) calculations can be used for all meteor showers active during the observing period. We can use the IMA parameter to estimate the influx of meteor particles to the Earth per hour, both for shower and sporadic meteors. The distribution of the influx rate (IMA) for the Perseids to the Earth for the observing periods in 2011 and 2012 is given. Distributions of Perseid meteors by stellar magnitude are also presented.

  1. Read Arizona.

    ERIC Educational Resources Information Center

    Arizona State Dept. of Library, Archives and Public Records, Phoenix.

    This manual, designed to help public libraries in Arizona to plan their summer reading programs for children, celebrates the 25th anniversary of the Arizona Reading Program. The material in the manual is prepared for libraries to adapt for their own uses. Chapters of the manual include: (1) Introductory Materials; (2) Goals, Objectives and…

  2. Shackleton Crater

    NASA Video Gallery

    This visualization, created using Lunar Reconnaissance Orbiter laser altimeter data, offers a view of Shackleton Crater located in the south pole of the moon. Thanks to these measurements, we now h...

  3. Copernicus (Crater)

    NASA Astrophysics Data System (ADS)

    Murdin, P.

    2000-11-01

    One of the Moon's most conspicuous craters, with a diameter of 93 km, centered at 9.7 °N, 20.1°W. It is named after the Polish astronomer Nicholas Copernicus. It is one of the Moon's younger features, the impact that produced it having taken place an estimated 1 billion years ago. Like other young craters it is surrounded by a system of bright rays formed by ejecta from the impact; the rays from ...

  4. Spallanzani Crater

    NASA Technical Reports Server (NTRS)

    2002-01-01

    [figure removed for brevity, see original site] (Released 17 July 2002) The craters on Mars display a variety of interior deposits one of which is shown here. Spallanzani Crater is located far enough south that it probably experiences the seasonal growth and retreat of the south polar cap. During the southern hemisphere winter, CO2 frost condenses out of the atmosphere onto the surface and probably brings with it small amounts of dust and even water ice. It is this sort of depositional process that is thought to have produced the polar layered deposits. The layered deposit in Spallanzani Crater shares some similarities with the polar deposits. Whatever the origin of the layered materials, they likely filled the crater at one time. Note how the interior slope of the northern rim displays layered material of similar if less distinct morphology as the main deposit on the floor. The process that filled the crater with sediment has been replaced by the opposite process. Erosion has taken over, leaving behind spectacular stair-stepped mesas and bizarre, contorted landforms. Unlike the interior crater deposits in the equatorial latitudes, the erosional process has not produced the yardang features that indicate wind erosion. It may be that ice was one of the cementing agents of the sediment and perhaps the sublimation of that ice has left the sediment susceptible to erosion. The details of the deposition and erosion of this interesting deposit remain to be discovered.

  5. Martian Meteor Ionization Layers

    NASA Technical Reports Server (NTRS)

    Grebowsky, J. M.; Pesnell, W. D.

    1999-01-01

    Small interplanetary grains bombard Mars, like all the solar system planets, and, like all the planets with atmospheres, meteoric ion and atom layers form in the upper atmosphere. We have developed a comprehensive one-dimensional model of the Martian meteoric ionization layer including a full chemical scheme. A persistent layer of magnesium ions should exist around an altitude of 70 km. Unlike the terrestrial case, where the metallic ions are formed via charge-exchange with the ambient ions, Mg(+) in the Martian atmosphere is produced by photoionization. Nevertheless, the predicted metal layer peak densities for Earth and Mars are similar. Diffusion solutions, such as those presented here, should be a good approximation of the metallic ions in regions where the magnetic field is negligible and may provide a significant contribution to the nightside ionosphere. The low ultraviolet absorption of the Martian atmosphere may make Mars an excellent laboratory in which to study meteoric ablation. Resonance lines not seen in the spectra of terrestrial meteors may be visible to a surface observatory in the Martian highlands.

  6. Asteroids, Comets, Meteors 1991

    NASA Technical Reports Server (NTRS)

    Harris, Alan W. (Editor); Bowell, Edward (Editor)

    1992-01-01

    Papers from the conference are presented and cover the following topics with respect to asteroids, comets, and/or meteors: interplanetary dust, cometary atmospheres, atmospheric composition, comet tails, astronomical photometry, chemical composition, meteoroid showers, cometary nuclei, orbital resonance, orbital mechanics, emission spectra, radio astronomy, astronomical spectroscopy, photodissociation, micrometeoroids, cosmochemistry, and interstellar chemistry.

  7. A Tale of 3 Craters

    NASA Technical Reports Server (NTRS)

    2004-01-01

    11 November 2004 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image captures some of the complexity of the martian upper crust. Mars does not simply have an impact-cratered surface, it's upper crust is a cratered volume. Over time, older craters on Mars have been eroded, filled, buried, and in some cases exhumed and re-exposed at the martian surface. The crust of Mars is layered to depths of 10 or more kilometers, and mixed in with the layered bedrock are a variety of ancient craters with diameters ranging from a few tens of meters (a few tens of yards) to several hundred kilometers (more than one or two hundred miles).

    The picture shown here captures some of the essence of the layered, cratered volume of the upper crust of Mars in a very simple form. The image shows three distinct circular features. The smallest, in the lower right quarter of the image, is a meteor crater surrounded by a mound of material. This small crater formed within a layer of bedrock that once covered the entire scene, but today is found only in this small remnant adjacent to the crater. The intermediate-sized crater, west (left) of the small one, formed either in the next layer down--that is, below the layer in which the small crater formed--or it formed in some layers that are now removed, but was big enough to penetrate deeply into the rock that is near the surface today. The largest circular feature in the image, in the upper right quarter of the image, is still largely buried. It formed in layers of rock that are below the present surface. Erosion has brought traces of its rim back to the surface of Mars. This picture is located near 50.0oS, 77.8oW, and covers an area approximately 3 km (1.9 mi) across. Sunlight illuminates this October 2004 image from the upper left.

  8. Oudemans Crater

    NASA Technical Reports Server (NTRS)

    2008-01-01

    This image of the interior of Oudemans Crater was taken by the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) at 1800 UTC (1:00 p.m. EDT) on October 2, 2006, near 9.8 degrees south latitude, 268.5 degrees east longitude. CRISM's image was taken in 544 colors covering 0.36-3.92 micrometers, and shows features as small as 20 meters (66 feet) across.

    Oudemans Crater is located at the extreme western end of Valles Marineris in the Sinai Planum region of Mars. The crater measures some 124 kilometers (77 miles) across and sports a large central peak.

    Complex craters like Oudemans are formed when an object, such as an asteroid or comet, impacts the planet. The size, speed and angle at which the object hits all determine the type of crater that forms. The initial impact creates a bowl-shaped crater and flings material (known as ejecta) out in all directions along and beyond the margins of the bowl forming an ejecta blanket. As the initial crater cavity succumbs to gravity, it rebounds to form a central peak while material along the bowl's rim slumps back into the crater forming terraces along the inner wall. If the force of the impact is strong enough, a central peak forms and begins to collapse back into the crater basin, forming a central peak ring.

    The uppermost image in the montage above shows the location of CRISM data on a mosaic taken by the Mars Odyssey spacecraft's Thermal Emission Imaging System (THEMIS). The CRISM data was taken inside the crater, on the northeast slope of the central peak.

    The lower left image is an infrared false-color image that reveals several distinctive deposits. The center of the image holds a ruddy-brown deposit that appears to correlates with a ridge running southwest to northeast. Lighter, buff-colored deposits occupy low areas interspersed within the ruddy-brown deposit. The southeast corner holds small hills that form part of the central peak complex.

    The lower right image shows spectral

  9. Studies of Transient Meteor Activity

    NASA Technical Reports Server (NTRS)

    Jenniskens, Peter M. M.

    2002-01-01

    Meteoroids bombard Earth's atmosphere daily, but occasionally meteor rates increase to unusual high levels when Earth crosses the relatively fresh ejecta of comets. These transient events in meteor activity provide clues about the whereabouts of Earth-threatening long-period comets, the mechanisms of large-grain dust ejection from comets, and the particle composition and size distribution of the cometary ejecta. Observations of these transient events provide important insight in natural processes that determine the large grain dust environment of comets, in natural phenomena that were prevalent during the time of the origin of life, and in processes that determine the hazard of civilizations to large impacts and of man-made satellites to the periodic blizzard of small meteoroids. In this proposal, three tasks form a coherent program aimed at elucidating various aspects of meteor outbursts, with special reference to planetary astronomy and astrobiology. Task 1 was a ground-based effort to observe periods of transient meteor activity. This includes: (1) stereoscopic imaging of meteors during transient meteor events for measurements of particle size distribution, meteoroid orbital dispersions and fluxes; and (2) technical support for Global-MS-Net, a network of amateur-operated automatic counting stations for meteor reflections from commercial VHF radio and TV broadcasting stations, keeping a 24h vigil on the level of meteor activity for the detection of new meteor streams. Task 2 consisted of ground-based and satellite born spectroscopic observations of meteors and meteor trains during transient meteor events for measurements of elemental composition, the presence of organic matter in the meteoroids, and products generated by the interaction of the meteoroid with the atmosphere. Task 3 was an airborne effort to explore the 2000 Leonid meteor outbursts, which are anticipated to be the most significant of transient meteor activity events in the remainder of the

  10. Tikhonravov Crater Dust Avalanches

    NASA Technical Reports Server (NTRS)

    2005-01-01

    [figure removed for brevity, see original site]

    Dust avalanches, also called slope streaks, occur on many Martian terrains. The deposition of airborne dust on surfaces causes a bright tone in the THEMIS VIS images. Any movement of the dust downhill, a dust avalanche, will leave behind a streak where the darker, dust-free surface is exposed.

    These dust avalanches are located within a small crater inside Tikhonravov Crater.

    Image information: VIS instrument. Latitude 12.6, Longitude 37.1 East (322.9 West). 36 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  11. Holden Crater Dune Field

    NASA Technical Reports Server (NTRS)

    2005-01-01

    [figure removed for brevity, see original site]

    Our topic for the weeks of April 4 and April 11 is dunes on Mars. We will look at the north polar sand sea and at isolated dune fields at lower latitudes. Sand seas on Earth are often called 'ergs,' an Arabic name for dune field. A sand sea differs from a dune field in two ways: 1) a sand sea has a large regional extent, and 2) the individual dunes are large in size and complex in form.

    A common location for dune fields on Mars is in the basin of large craters. This dune field is located in Holden Crater at 25 degrees South atitude.

    Image information: VIS instrument. Latitude -25.5, Longitude 326.8 East (33.2 West). 19 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  12. Kaiser Crater DCS

    NASA Technical Reports Server (NTRS)

    2004-01-01

    [figure removed for brevity, see original site]

    Released July 29, 2004 This image shows two representations of the same infra-red image covering a portion of Kaiser Crater. On the left is a grayscale image showing surface temperature, and on the right is a false-color composite made from 3 individual THEMIS bands. The false-color image is colorized using a technique called decorrelation stretch (DCS), which emphasizes the spectral differences between the bands to highlight compositional variations.

    In this image, the basaltic sand dunes in bottom of Kaiser crater are colored a bright pink/magenta. The spectral features are clean and prominent on these dust-free surfaces and the dark color of the basaltic dunes helps them to absorb sunlight and produces higher surface temperatures, which also contributes to the image colors.

    Image information: IR instrument. Latitude -46.5, Longitude 20.3 East (339.7 West). 100 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin

  13. Elemental abundance determinations for meteors by spectroscopy.

    NASA Technical Reports Server (NTRS)

    Harvey, G. A.

    1973-01-01

    Relative elemental abundance determinations for meteors by spectroscopy are discussed. Relative abundances of spectroscopically accessible elements of four major shower meteors and one sporadic meteor are presented. A sporadic meteor with dominant sodium radiation and an iron-deficient sporadic meteor are analyzed. Empirical and theoretical tests for self-absorption in optical meteor plasmas have been conducted. Both ionization and incomplete dissociation are found to severely deplete certain neutral atoms from meteor plasmas.

  14. Electrophonic sounds in meteors

    NASA Astrophysics Data System (ADS)

    Wu, Guangjie

    2003-06-01

    Recordings about the sounds of meteors existed in ancient Chinese literature before Christ. During recent two hundreds years, especially, recent twenty years, reports and investigations about Electrophonic meteors and Electrophonic sounds have been developed largely. Electrophonic sounds are defined as sounds produced by direct conversion of electromagnetic radiation into audible sounds. It is thought that Electrophonic sounds may be induced in events of bolide, very bright auroral display, nearby strong lightning, earthquake and nuclear explosion. However, on account of its unusually rare chance and its particular physical course, no matter in observations or in theoretical study, there are many difficult and unresolved problems. The historical and present situations about Electrophonic sounds are summarized in this paper.

  15. Meteor signature interpretation

    SciTech Connect

    Canavan, G.H.

    1997-01-01

    Meteor signatures contain information about the constituents of space debris and present potential false alarms to early warnings systems. Better models could both extract the maximum scientific information possible and reduce their danger. Accurate predictions can be produced by models of modest complexity, which can be inverted to predict the sizes, compositions, and trajectories of object from their signatures for most objects of interest and concern.

  16. Stop Sign Crater

    NASA Technical Reports Server (NTRS)

    2003-01-01

    [figure removed for brevity, see original site]

    With its rim eroded off by catastrophic floods in Tiu Vallis and its strangely angular shape, this 12 km diameter crater looks vaguely like a stop sign.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

    Image information: VIS instrument. Latitude 8.6, Longitude 329.2 East (30.8 West). 19 meter/pixel resolution.

  17. Concentric Crater Fill

    NASA Technical Reports Server (NTRS)

    2003-01-01

    [figure removed for brevity, see original site]

    The bizarre patterns on the floor of this crater in Nilosyrtis Mensae defy an easy explanation. At 34 degrees north latitude, this location hardly qualifies as 'Arctic' yet it is likely that some form of periglacial process possibly combined with the vaporization of ground ice is responsible for this intriguing landscape.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

    Image information: VIS instrument. Latitude 10.3, Longitude 24.5 East (284.5 West). 19 meter/pixel resolution.

  18. Crater Appeal

    ERIC Educational Resources Information Center

    Mueller, Michael P.; Valderrama, Paige

    2006-01-01

    For many years, the planet Mars was nothing more than a little red dot in a sea of stars and a blur in many science classrooms. Recent focus on the planet, however, has led to incredible teaching opportunities, such as the Mars Student Imaging Project (MSIP) facilitated by Arizona State University's Mars Education Program. The MSIP curriculum…

  19. Meteors in Australian Aboriginal Dreamings

    NASA Astrophysics Data System (ADS)

    Hamacher, Duane W.; Norris, Ray P.

    2010-06-01

    We present a comprehensive analysis of Australian Aboriginal accounts of meteors. The data used were taken from anthropological and ethnographic literature describing oral traditions, ceremonies, and Dreamings of 97 Aboriginal groups representing all states of modern Australia. This revealed common themes in the way meteors were viewed between Aboriginal groups, focusing on supernatural events, death, omens, and war. The presence of such themes around Australia was probably due to the unpredictable nature of meteors in an otherwise well-ordered cosmos.

  20. Galle Crater

    NASA Technical Reports Server (NTRS)

    2002-01-01

    (Released 19 June 2002) The Science This image is of part of Galle Crater, located at 51.9S, 29.5W. This image was taken far enough south and late enough into the southern hemisphere fall to catch observe water ice clouds partially obscuring the surface. The most striking aspect of the surface is the dissected layered unit to the left in the image. Other areas also appear to have layering, but they are either more obscured by clouds or are less well defined on the surface. The layers appear to be mostly flat lying and layer boundaries appear as topographic lines would on a map, but there are a few areas where it appears that these layers have been deformed to some level. Other areas of the image contain rugged, mountainous terrain as well as a separate pitted terrain where the surface appears to be a separate unit from the mountains and the layered terrain. The Story Galle Crater is officially named after a German astronomer who, in 1846, was the first to observe the planet Neptune. It is better known, however, as the 'Happy Face Crater.' The image above focuses on too small an area of the crater to see its beguiling grin, but you can catch the rocky line of a 'half-smile' in the context image to the right (to the left of the red box). While water ice clouds make some of the surface harder to see, nothing detracts from the fabulous layering at the center left-hand edge of the image. If you click on the above image, the scalloped layers almost look as if a giant knife has swirled through a landscape of cake frosting. These layers, the rugged, mountains near them, and pits on the surface (upper to middle section of the image on the right-hand side) all create varying textures on the crater floor. With such different features in the same place, geologists have a lot to study to figure out what has happened in the crater since it formed.

  1. Meteor Beliefs Project: Meteoric references in Ovid's Metamorphoses

    NASA Astrophysics Data System (ADS)

    Gheorghe, A. D.; McBeath, A.

    2003-10-01

    Three sections of Ovid's Metamorphoses are examined, providing further information on meteoric beliefs in ancient Roman times. These include meteoric imagery among the portents associated with the death of Julius Caesar, which we mentioned previously from the works of William Shakespeare (McBeath and Gheorghe, 2003b).

  2. James Joule and meteors

    NASA Astrophysics Data System (ADS)

    Hughes, David W.

    1989 was the hundredth anniversary of the death of James Prescott Joule, the Prescott being his mother's family name and the Joule, rhyming with cool, originating from the Derbyshire village of Youlgreave. Joule is rightly famous for his experimental efforts to establish the law of conservation of energy, and for the fact that J, the symbol known as the mechanical equivalent of heat, is named after him. Astronomically his "light has been hidden under a bushel". James Joule had a major influence on the physics of meteors.

  3. High geocentric velocity meteor ablation

    NASA Astrophysics Data System (ADS)

    Hill, K. A.; Rogers, L. A.; Hawkes, R. L.

    2005-12-01

    Interstellar origin meteoroids have now been detected using radar, image intensified video, large aperture radar and space dust impact techniques. Dynamical and radiation production mechanisms will eject some meteoroids from other planetary systems into orbits which will impact Earth with high geocentric velocities. In this paper we numerically model the ablation of high geocentric velocity (71 to 500~km s-1) meteors in order to predict the heights, light curves and trail lengths to be expected. We modeled three compositions and structures: asteroidal, cometary and porous cometary. Meteoroid masses ranging from 10-6 to 10-13~kg were used in the model. As expected, these high geocentric velocity meteors, when compared to other meteors, ablate higher in the atmosphere. For example a 300~km s-1 cometary structure meteor of mass 10-9~kg will have a peak luminosity at about 190 km. They will also have significantly longer trail lengths. The same 300~km s-1, 10-9~kg cometary meteor would be within 2 mag of its peak brightness for a vertical displacement of 60 km if incident at a zenith angle of 45°. The peak light intensity of these high geocentric velocity meteors changes only slowly with velocity. Although the incident kinetic energy per unit time increases dramatically, this is largely offset by a decrease in the optical luminous efficiency in this velocity regime according to our luminous efficiency model. The 300~km s-1, 10-9~kg cometary meteor would have an absolute meteor magnitude at peak luminosity of about +8.5 mag. Our results suggest that at least those high geocentric velocity meteors larger than about 10-8~kg should be observable with current meteor electro-optical technology although there may be observational biases against their detection. The results of this paper can be used to help optimize a search strategy for these very high geocentric velocity meteors.

  4. Centrifuge impact cratering experiment 5

    NASA Technical Reports Server (NTRS)

    1984-01-01

    Transient crates motions, cratering flow fields, crates dynamics, determining impact conditions from total crater welt, centrifuge quarter-space cratering, and impact cratering mechanics research is documented.

  5. Antum Crater

    NASA Technical Reports Server (NTRS)

    1997-01-01

    This image shows the location of one of the highest spatial resolution NIMS images acquired. The left image is an airbrush map of the surface of Ganymede from Voyager data. The small square shows the location of Antum crater, target of the high-resolution NIMS image on the right. NIMS spatial resolution is approximately 4 km/pixel and the image is a falsely colored albedo for a single wavelength near 0.8 micrometers.

    Antum is what is known as a dark ray crater, that is, dark lines emanate from the central bright area. This NIMS image is a close-up of the central area and the dark rays are off the edges of the image. Dark ray craters are fairly unusual and are concentrated in one area of Ganymede's surface. They are thought to be composed of material from the body that impacted Ganymede and created the crater, rather than material brought up from the subsurface. Analysis of the NIMS data will yield compositional and mineralogical information on the dark material. This can help us to understand the nature of bodies that 'crash' into the Jupiter system, as did Comet Shoemaker-Levy 9 in 1995, as well as give more information on the history of surface modification on Ganymede.

    The Jet Propulsion Laboratory, Pasadena, CA manages the mission for NASA's Office of Space Science, Washington, DC.

    The Jet Propulsion Laboratory, Pasadena, CA manages the mission for NASA's Office of Space Science, Washington, DC.

    This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://galileo.jpl.nasa.gov.

  6. Meteor fireball sounds identified

    NASA Technical Reports Server (NTRS)

    Keay, Colin

    1992-01-01

    Sounds heard simultaneously with the flight of large meteor fireballs are electrical in origin. Confirmation that Extra/Very Low Frequency (ELF/VLF) electromagnetic radiation is produced by the fireball was obtained by Japanese researchers. Although the generation mechanism is not fully understood, studies of the Meteorite Observation and Recovery Project (MORP) and other fireball data indicate that interaction with the atmosphere is definitely responsible and the cut-off magnitude of -9 found for sustained electrophonic sounds is supported by theory. Brief bursts of ELF/VLF radiation may accompany flares or explosions of smaller fireballs, producing transient sounds near favorably placed observers. Laboratory studies show that mundane physical objects can respond to electrical excitation and produce audible sounds. Reports of electrophonic sounds should no longer be discarded. A catalog of over 300 reports relating to electrophonic phenomena associated with meteor fireballs, aurorae, and lightning was assembled. Many other reports have been cataloged in Russian. These may assist the full solution of the similar long-standing and contentious mystery of audible auroral displays.

  7. Arizona Fires

    Atmospheric Science Data Center

    2014-05-15

    ... the second largest fire in Arizona history. More than 2,000 people are working to contain the fire, which is being driven by high winds and ... bright desert background. The areas with no data (shown in black and present at the oblique angles) are locations where the variable ...

  8. Advanced meteor wind observations using meteor and MST radars

    NASA Astrophysics Data System (ADS)

    Tsutsumi, M.; Aso, T.; Hall, C.; Nakamura, T.; Sato, K.; Sato, T.

    A few topics from recent developments of radio meteor observation techniques are presented The Nippon Norway Tromsoe Meteor Radar NTMR has been in continuous operation since November 2003 in Tromsoe 69N One of the major advantages of the present meteor radar is its high echo rate 6000-20000 echoes a day despite the relatively small transmitting power 7 5kW peak From ambipolar diffusion coefficients we have successfully extracted atmospheric temperature fluctuations due to gravity waves assuming the Boussinesq approximation The time and height resolutions of horizontal winds and temperature fluctuations at the altitude of 90 km are 1 hour and 2km high enough for the study of gravity waves with a period longer than a few hours Horizontal propagation characteristics of gravity waves are further studied using a theoretical phase relation between the wind and temperature fluctuations MST radars in the VHF band have a great potential in meteor echo observations due to their high transmitting power The meteor measurement can be conducted throughout a day and complement the turbulent echo measurement in the mesosphere which is limited to daylight hours only The MU radar of Kyoto University is one of those radars and has been successfully applied to meteor studies by utilizing its very high versatility The MU radar was recently renewed Its signal processing unit is up-graded from a 4 analog receiver system to a 25 digital receiver system In the present study we try to improve the MU radar meteor measurement

  9. The Chelyabinsk meteor

    NASA Astrophysics Data System (ADS)

    Popova, O.; Jenniskens, P.; Shuvalov, V.; Emel'yanenko, V.; Rybnov, Y.; Kharlamov, V.; Kartashova, A.; Biryukov, E.; Khaibrakhmanov, S.

    2014-07-01

    A review is given about what was learned about the 0.5-Mt Chelyabinsk airburst of 15 February 2013 by field studies, the analysis of recovered meteorites, and numerical models of meteoroid fragmentation and airburst propagation. Previous events with comparable or larger energy in recent times include only the 0.5-Mt -sized 3 August 1963 meteor over the south Atlantic, for which only an infrasound signal was recorded, and the famous Tunguska impact of 1908. Estimates of the initial kinetic energy of the Tunguska impact range from 3 to 50 Mt, due to the lack of good observations at the time. The Chelyabinsk event is much better documented than both, and provides a unique opportunity to calibrate the different approaches used to model meteoroid entry and calculate the damaging effects of a shock wave from a large meteoroid impact. A better understanding of what happened might help future impact hazard mitigation efforts by calibrating models of what might happen under somewhat different circumstances. The initial kinetic energy is estimated from infrasonic signals and the fireball's lightcurve, as well as the extent of the glass damage on the ground. Analysis of video observations of the fireball and the shadow movements provided an impact trajectory and a record of the meteor lightcurve, which describes how that energy was deposited in the atmosphere. Ablation and fragmentation scenarios determine the success of attempts to reproduce the observed meteor lightcurve and deceleration profile by numerical modeling. There was almost no deceleration until peak brightness. Meteoroid fragmentation occurred in different forms, some part of the initial mass broke in well separated fragments, the surviving fragments falling on the ground as meteorites. The specific conditions during energy deposition determined the fraction of surviving mass. The extent of the glass damage was mapped by visiting over 50 villages in the area. A number of numerical simulations were conducted that

  10. Regolith transport in craters on Eros

    NASA Astrophysics Data System (ADS)

    Mantz, A.; Sullivan, R.; Veverka, J.

    2004-01-01

    Images of Eros from the NEAR Shoemaker spacecraft reveal bright and dark albedo features on steep crater walls unlike markings previously observed on asteroids. These features have been attributed to the downslope movement of space-weathered regolith, exposing less weathered material (Science 292 (2001) 484; Meteor. Planet. Sci. 36 (2001) 1617; Icarus 155 (2002) 145). Here we present observations of the interiors of large craters (>1 km in diameter) to test this hypothesis and constrain the origin of the features. We find that bright regions in these craters correspond to steep slopes, consistent with previous work. The geographic distribution of craters with albedo variations shows no pattern and does not resemble the distribution of ponds, another phenomenon on Eros attributed to regolith movement. Shadows and other indications of topography are not observed at feature boundaries, implying that the transported layer is ⩽1 m thick. The presence of multiple bright and dark units on long slopes with sharp boundaries between them suggests that mobilized regolith may be halted by frictional or other effects before reaching the foot of the slope. Features on crater walls should darken at the same rate as bright ejecta deposits from crater formation; the lack of observed, morphologically fresh craters with bright interiors or ejecta suggests that the albedo patterns are younger than the most recently formed craters greater than about 100 m in diameter. Smaller or micrometeorite impacts, which would not necessarily leave evident deposits of bright ejecta, remain possible causes of albedo patterns. Although their effectiveness is difficult to assess, electrostatic processes and thermal creep are also candidates.

  11. Moreux Crater Dunes

    NASA Technical Reports Server (NTRS)

    2005-01-01

    [figure removed for brevity, see original site]

    The THEMIS VIS camera is capable of capturing color images of the Martian surface using five different color filters. In this mode of operation, the spatial resolution and coverage of the image must be reduced to accommodate the additional data volume produced from using multiple filters. To make a color image, three of the five filter images (each in grayscale) are selected. Each is contrast enhanced and then converted to a red, green, or blue intensity image. These three images are then combined to produce a full color, single image. Because the THEMIS color filters don't span the full range of colors seen by the human eye, a color THEMIS image does not represent true color. Also, because each single-filter image is contrast enhanced before inclusion in the three-color image, the apparent color variation of the scene is exaggerated. Nevertheless, the color variation that does appear is representative of some change in color, however subtle, in the actual scene. Note that the long edges of THEMIS color images typically contain color artifacts that do not represent surface variation.

    This false color image shows part of the interior of Moreux Crater. The crater peak is at the right edge of the image. Many dunes and a dunefield are also visible in the iamge. This image was collected during the Northern Spring season.

    Image information: VIS instrument. Latitude 41.9, Longitude 44.1 East (315.9 West). 35 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

  12. Crater Dust Avalanches

    NASA Technical Reports Server (NTRS)

    2005-01-01

    [figure removed for brevity, see original site]

    Dust avalanches, also called slope streaks, occur on many Martian terrains. The deposition of airborne dust on surfaces causes a bright tone in the THEMIS VIS images. Any movement of the dust downhill, a dust avalanche, will leave behind a streak where the darker, dust-free surface is exposed.

    These dust avalanches are located in a small canyon within a crater rim northeast of Naktong Vallis.

    Image information: VIS instrument. Latitude 7.1, Longitude 34.7 East (325.3 West). 17 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  13. Crater Dust Avalanches

    NASA Technical Reports Server (NTRS)

    2005-01-01

    [figure removed for brevity, see original site]

    Dust avalanches, also called slope streaks, occur on many Martian terrains. The deposition of airborne dust on surfaces causes a bright tone in the THEMIS VIS images. Any movement of the dust downhill, a dust avalanche, will leave behind a streak where the darker, dust-free surface is exposed.

    This region of dust avalanches is located in and around a crater to the west of yesterday's image.

    Image information: VIS instrument. Latitude 14.7, Longitude 32.7 East (327.3 West). 18 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  14. Crater Floor Dune Field

    NASA Technical Reports Server (NTRS)

    2005-01-01

    [figure removed for brevity, see original site]

    Our topic for the weeks of April 4 and April 11 is dunes on Mars. We will look at the north polar sand sea and at isolated dune fields at lower latitudes. Sand seas on Earth are often called 'ergs,' an Arabic name for dune field. A sand sea differs from a dune field in two ways: 1) a sand sea has a large regional extent, and 2) the individual dunes are large in size and complex in form.

    Our final dune image shows a small dune field inside an unnamed crater south of Nili Fossae.

    Image information: VIS instrument. Latitude 20.6, Longitude 79 East (281 West). 19 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  15. Chipped Paint Crater

    NASA Technical Reports Server (NTRS)

    2003-01-01

    [figure removed for brevity, see original site]

    Released 9 April 2003

    In the high northern latitudes NW of Alba Patera, a smooth mantle of material that covers the landscape appears chipped away from the rim of a large crater. The prominent scarp that has formed from the retreat of the mantle lacks the rounded appearance of other ice-rich mantles found in the mid-latitudes. The nature of this mantling layer therefore is more enigmatic.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

    Image information: VIS instrument. Latitude 62.9, Longitude 226.2 East (133.8 West). 19 meter/pixel resolution.

  16. Catalogue of representative meteor spectra

    NASA Astrophysics Data System (ADS)

    Vojáček, V.; Borovička, J.; Koten, P.; Spurný, P.; Štork, R.

    2015-08-01

    Aims: We present a library of low-resolution meteor spectra that includes sporadic meteors, members of minor meteor showers, and major meteor showers. These meteors are in the magnitude range from +2 to -3, corresponding to meteoroid sizes from 1 mm to 10 mm. Methods: Parallel double-station video observations allowed us to compute heliocentric orbits for all meteors. Most observations were performed during the periods of activity of major meteor showers in the years between 2006 and 2012. Spectra are classified according to relative intensities of the low-temperature emission lines of Mg, Na, and Fe. Results: Shower meteors were found to be of normal composition, except for Southern δ Aquariids and some members of the Geminid shower, neither of which have Na in the meteor spectra. Variations in Na content are typical for the Geminid shower. Three populations of Na-free mereoroids were identified. The first population are iron meteorites, which have an asteroidal-chondritic origin, but one meteoroid with low perihelion (0.11 AU) was found among the iron meteorites. The second population were Sun-approaching meteoroids in which sodium is depleted by thermal desorption. The third population were Na-free meteoroids of cometary origin. Long exposure to cosmic rays on the surface of comets in the Oort cloud and disintegration of this crust might be the origin of this population of meteoroids. Spectra (Figs. 17-30) are only, Tables 4-6 are also available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/580/A67

  17. Artificial meteor test towards: On-demand meteor shower

    NASA Astrophysics Data System (ADS)

    Abe, S.; Okajima, L.; Sahara, H.; Watanabe, T.; Nojiri, Y.; Nishizono, T.

    2016-01-01

    An arc-heated wind tunnel is widely used for ground-based experiments to simulate environments of the planetary atmospheric entry under hypersonic and high-temperature conditions. In order to understand details of a meteor ablation such as temperature, composition ratio and fragmentation processes, the artificial meteor test was carried out using a JAXA/ISAS arc-heated wind tunnel. High-heating rate around 30 MW/m2 and High-enthalpy conditions, 10000 K arc-heated flow at velocity around 6 km/s were provided. Newly developed artificial metallic meteoroids and real meteorites such as Chelyabinsk were used for the ablation test. The data obtained by near-ultraviolet and visible spectrograph (200 and 1100nm) and high-speed camera (50 μs) have been examined to develop more efficient artificial meteor materials. We will test artificial meteors from a small satellite in 2018.

  18. Maunder Crater

    NASA Technical Reports Server (NTRS)

    2002-01-01

    (Released 24 May 2002) The Science This image is of a portion of Maunder Crater located at about 49 S and 358 W (2 E). There are a number of interesting features in this image. The lower left portion of the image shows a series of barchan dunes that are traveling from right to left. The sand does not always form dunes as can be seen in the dark and diffuse areas surrounding the dune field. The other interesting item in this image are the gullies that can be seen streaming down from just beneath a number of sharp ridgelines in the upper portion of the image. These gullies were first seen by the MOC camera on the MGS spacecraft and it is though that they formed by groundwater leaking out of the rock layers on the walls of craters. The water runs down the slope and forms the fluvial features seen in the image. Other researchers think that these features could be formed by other fluids, such as CO2. These features are typically seen on south facing slopes in the southern hemisphere, though this image has gullies on north facing slopes as well. The Story Little black squigglies seem to worm their way down the left-hand side of this image. These land features are called barchan (crescent-shaped) dunes. Barchan dunes are found in sandy deserts on Earth, so it's no surprise the Martian wind makes them a common site on the red planet too. They were first named by a Russian scientist named Alexander von Middendorf, who studied the inland desert dunes of Turkistan. The barchan dunes in this image occur in the basin of Maunder crater on Mars, and are traveling from right to left. The sand does not always form dunes, though, as can be seen in the dark areas of scattered sand surrounding the dune field. Look for the streaming gullies that appear just beneath a number of sharp ridgelines in the upper portion of the image. These gullies were first discovered by the Mars Orbital Camera on the Mars Global Surveyor spacecraft. While most crater gullies are found on south

  19. A Crater Split In Two

    NASA Technical Reports Server (NTRS)

    2003-01-01

    [figure removed for brevity, see original site]

    Released 23 September 2003

    A 22 km-diameter crater has been sliced by the tectonic forces that produced the rift known as Sirenum Fossae. The orientation of this rift is roughly radial to the great Tharsis volcano Arsia Mons, probably indicating a link between the formation of the rift and the volcano. Note how the rift cuts through a jumble of mounds on the floor of the crater. This indicates a sequence of events beginning with the formation of the crater followed by an infilling of material that was then eroded into the mounds and ultimately split open by the shifting martian crust.

    Image information: VIS instrument. Latitude -29.7, Longitude 211.7 East (148.3 West). 19 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  20. Letter - Reply: Meteors in Australian Aboriginal Dreamings

    NASA Astrophysics Data System (ADS)

    Hamacher, Duane W.

    2011-06-01

    In response to the letter by Gorelli (2010) about Hamacher & Norris (2010), he is quite right about Aboriginal people witnessing impact events in Australia. There are several oral traditions regarding impact sites, some of which were probably witnessed, as Gorelli pointed out. The Henbury craters he mentions, with a young age of only ∼ 4200 years, have oral traditions that seem to describe a cosmic impact, including an aversion to drinking water that collects in the craters in fear that the fire-devil (which came from the sun, according to an Elder) would rain iron in them again. Other impact sites, such as Gosse's Bluff crater (Tnorala in the Arrernte language) and Wolfe Creek crater (Kandimalal in the Djaru language) have associated impact stories, despite their old ages (142 Ma and ∼0.3 Ma, respectively). In addition, many fireball and airburst events are described in Aboriginal oral traditions, a number of which seem to indicate impact events that are unknown to Western science. I have published a full treatise of meteorite falls and impact events in Australian Aboriginal culture that I would like to bring to the attention of Gorelli and WGN readers (Hamacher & Norris, 2009). Although our paper was published in the 2009 volume of Archaeoastronomy, it did not appear in print until just recently, which is probably why it has gone unnoticed. Recent papers describing the association between meteorites and Aboriginal cosmology (Hamacher, 2011) and comets in Aboriginal culture (Hamacher & Norris, 2011) have also been published, and would likely be of interest to WGN readers. I heartily agree with Gorelli that oral traditions are fast disappearing, taking with them a wealth of information about not only that peoples' culture, but also about past geologic and astronomical events, such as meteorite falls and cosmic impacts (a branch of the growing field of Geomythology). There is an old saying that "when a man dies, a library goes with him". This is certainly the

  1. Meteor Beliefs Project: Seven years and counting

    NASA Astrophysics Data System (ADS)

    McBeath, A.; Drobnock, G. J.; Gheorghe, A. D.

    2010-04-01

    The Meteor Beliefs Project's seventh anniversary is celebrated with an eclectic mixture of meteor beliefs from the 1799 Leonids in Britain, the folkloric link between meteors and wishing in some Anglo-American sources, how a meteoric omen came to feature in Nathaniel Hawthorne's 1850 novel The Scarlet Letter, and a humorous item from the satirical magazine Punch in 1861, all helping to show how meteor beliefs can be transformed by different parts of society.

  2. Signs of Landscape Modifications at Martian Crater

    NASA Technical Reports Server (NTRS)

    2009-01-01

    [figure removed for brevity, see original site] Click on the image for larger version

    The lower portion of this image from the Thermal Emission Imaging System camera (THEMIS) on NASA's Mars Odyssey orbiter shows a crater about 16 kilometers (10 miles) in diameter with features studied as evidence of deposition or erosion. The crater is centered at 40.32 degrees south latitude and 132.5 degrees east longitude, in the eastern portion of the Hellas basin on Mars. It has gullies and arcuate ridges on its north, pole-facing interior wall. This crater is in the center of a larger (60-kilometer or 37-mile diameter) crater with lobate flows on its north, interior wall. The image, number V07798008 in the THEMIS catalog, covers a swath of ground 17.4 kilometers (10.8 miles) wide.

    NASA's Jet Propulsion Laboratory manages the Mars Odyssey mission for NASA's Office of Space Science. THEMIS was developed by Arizona State University in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  3. Geologic map of the eastern quarter of the Flagstaff 30’ x 60’ quadrangle, Coconino County, northern Arizona

    USGS Publications Warehouse

    Billingsley, George H.; Block, Debra; Hiza-Redsteer, Margaret

    2014-01-01

    The eastern quarter of the Flagstaff 30′ x 60′ quadrangle includes eight USGS 1:24,000-scale quadrangles in Coconino County, northern Arizona (fig. 1, map sheet): Anderson Canyon, Babbitt Wash, Canyon Diablo, Grand Falls, Grand Falls SE, Grand Falls SW, Grand Falls NE, and Meteor Crater. The map is bounded by lat 35° to 35°30′ N. and long 111° to 111°15′ W. and is on the southern part of the Colorado Plateaus geologic province (herein Colorado Plateau). Elevations range from 4,320 ft (1,317 m) at the Little Colorado River in the northwest corner of the map area to about 6,832 ft (2,082 m) at the southwest corner of the map. This geologic map provides an updated geologic framework for the eastern quarter of the Flagstaff 30′ x 60′ quadrangle and is adjacent to two other recent geologic maps, the Cameron and Winslow 30′ x 60′ quadrangles (Billingsley and others, 2007, 2013). This geologic map is the product of a cooperative effort between the U.S. Geological Survey (USGS) and the Navajo Nation. It provides geologic information for resource management officials of the U.S. Forest Service, the Arizona Game and Fish Department, and the Navajo Nation Reservation (herein the Navajo Nation). Funding for the map was provided by the USGS geologic mapping program, Reston, Virginia. Field work on the Navajo Nation was conducted under a permit from the Navajo Nation Minerals Department. Any persons wishing to conduct geologic investigations on the Navajo Nation must first apply for, and receive, a permit from the Navajo Nation Minerals Department, P.O. Box 1910, Window Rock, Arizona 86515, telephone (928) 871-6587.

  4. Coded continuous wave meteor radar

    NASA Astrophysics Data System (ADS)

    Vierinen, Juha; Chau, Jorge L.; Pfeffer, Nico; Clahsen, Matthias; Stober, Gunter

    2016-03-01

    The concept of a coded continuous wave specular meteor radar (SMR) is described. The radar uses a continuously transmitted pseudorandom phase-modulated waveform, which has several advantages compared to conventional pulsed SMRs. The coding avoids range and Doppler aliasing, which are in some cases problematic with pulsed radars. Continuous transmissions maximize pulse compression gain, allowing operation at lower peak power than a pulsed system. With continuous coding, the temporal and spectral resolution are not dependent on the transmit waveform and they can be fairly flexibly changed after performing a measurement. The low signal-to-noise ratio before pulse compression, combined with independent pseudorandom transmit waveforms, allows multiple geographically separated transmitters to be used in the same frequency band simultaneously without significantly interfering with each other. Because the same frequency band can be used by multiple transmitters, the same interferometric receiver antennas can be used to receive multiple transmitters at the same time. The principles of the signal processing are discussed, in addition to discussion of several practical ways to increase computation speed, and how to optimally detect meteor echoes. Measurements from a campaign performed with a coded continuous wave SMR are shown and compared with two standard pulsed SMR measurements. The type of meteor radar described in this paper would be suited for use in a large-scale multi-static network of meteor radar transmitters and receivers. Such a system would be useful for increasing the number of meteor detections to obtain improved meteor radar data products.

  5. A Bright Lunar Impact Flash Linked to the Virginid Meteor Complex

    NASA Technical Reports Server (NTRS)

    Moser, D. E.; Suggs, R. M.; Suggs, R. J.

    2015-01-01

    On 17 March 2013 at 03:50:54 UTC, NASA detected a bright impact flash on the Moon caused by a meteoroid impacting the lunar surface. There was meteor activity in Earth's atmosphere the same night from the Virginid Meteor Complex. The impact crater associated with the impact flash was found and imaged by Lunar Reconnaissance Orbiter (LRO). Goal: Monitor the Moon for impact flashes produced by meteoroids striking the lunar surface. Determine meteoroid flux in the 10's gram to kilogram size range.

  6. Craters in the Seabed of the Gulf of California Caused by Volcanic Explosion? Volcanic Subsidence? Meteoroid Impact? Hydrocarbon Venting? or Dissolution?

    NASA Astrophysics Data System (ADS)

    Lonsdale, P.; Eakins, B.; Castillo, P.

    2004-12-01

    Several circular enclosed depressions were mapped at depths of 500 to 2500m during a multibeam sonar survey of the Gulf of California. Those on the summits and flanks of volcanic seamounts were caused by volcanic explosions or by subsidence following magma withdrawal, but the origins of the others, in both oceanic and continental crust, are more problematic. Multiple working hypotheses are being tested with geophysical data and rock-sample analysis. A fresh circular crater similar in size to Meteor Crater, Arizona but deeper (2km diameter, with a flat floor at 2185m below sea-level, 500m deeper than parts of its rim) indents young, faulted oceanic crust in rift mountains just 6km from the North Pescadero spreading axis. This axis, believed to spread a half-rate of 24km/Myr, accretes mainly a sediment-sill complex, with very localized eruptions of tholeiitic lava. Dredging of the steep (30 to 45° ) crater walls and rim recovered mudstone and angular boulders of basalt, and destroyed one dredge that grabbed a boulder too large to lift. The faulted rift walls 2km from the crater yielded mudstone and basalt fragments, plus rounded boulders (crater ejecta?) composed mainly of fresh tholeiitic glass. The most plausible, perhaps equally improbable, genetic hypotheses are (i) volcanic explosion when magma intruded off-axis into the sediment-sill complex and interacted with pore water, and (ii) meteoroid impact. Craters of a different type dissect the thick deformed sediment on the 1700 to 400m-deep crest of a transform ridge along the Guaymas Basin margin. Shallow pockmarks around discharges of hydrothermally generated hydrocarbons have been explored with submersibles on the deeper part of the ridge. The larger craters (0.5 to 2km diameter, 100 to 400m deep) that we found where the crest is 600 to 500m deep probably have the same origin (explosive release through a near-surface clathrate horizon of hydrocarbons that migrated up-dip from Guaymas Basin); a possible

  7. Crater chains on Mercury

    NASA Astrophysics Data System (ADS)

    Shevchenko, V.; Skobeleva, T.

    After discovery of disruption comet Shoemaker-Levy 9 into fragment train before it's collision with Jupiter there was proposed that linear crater chains on the large satellites of Jupiter and on the Moon are impact scars of past tidally disrupted comets.It's known that radar images have revealed the possible presence of water ice deposits in polar regions of Mercury. Impacts by a few large comets seem to provide the best explanation for both the amount and cleanliness of the ice deposits on Mercury because they have a larger volatile content that others external sources, for example, asteroid. A number of crater chains on the surface of Mercury are most likely the impact tracks of "fragment trains" of comets tidally disrupted by Sun or by Mercury and are not secondary craters. Mariner 10 image set (the three Mariner 10 flybys in 1974-1975) was used to recognize the crater chains these did not associate with secondary crater ejecta from observed impact structures. As example, it can be shown such crater chain located near crater Imhotep and crater Ibsen (The Kuiper Quadrangle of Mercury). Resolution of the Mariner 10 image is about 0.54 km/pixel. The crater chain is about 50 km long. It was found a similar crater chain inside large crater Sophocles (The Tolstoj Quadrangle of Mercury). The image resolution is about 1.46 km/pixel. The chain about 50 km long is located in northen part of the crater. Image resolution limits possibility to examine the form of craters strongly. It seems the craters in chains have roughly flat floor and smooth form. Most chain craters are approximately circular. It was examined many images from the Mariner 10 set and there were identified a total 15 crater chains and were unable to link any of these directly to any specific large crater associated with ejecta deposits. Chain craters are remarkably aligned. All distinguished crater chains are superposed on preexisting formations. A total of 127 craters were identified in the 15 recognized

  8. Coded continuous wave meteor radar

    NASA Astrophysics Data System (ADS)

    Vierinen, J.; Chau, J. L.; Pfeffer, N.; Clahsen, M.; Stober, G.

    2015-07-01

    The concept of coded continuous wave meteor radar is introduced. The radar uses a continuously transmitted pseudo-random waveform, which has several advantages: coding avoids range aliased echoes, which are often seen with commonly used pulsed specular meteor radars (SMRs); continuous transmissions maximize pulse compression gain, allowing operation with significantly lower peak transmit power; the temporal resolution can be changed after performing a measurement, as it does not depend on pulse spacing; and the low signal to noise ratio allows multiple geographically separated transmitters to be used in the same frequency band without significantly interfering with each other. The latter allows the same receiver antennas to be used to receive multiple transmitters. The principles of the signal processing are discussed, in addition to discussion of several practical ways to increase computation speed, and how to optimally detect meteor echoes. Measurements from a campaign performed with a coded continuous wave SMR are shown and compared with two standard pulsed SMR measurements. The type of meteor radar described in this paper would be suited for use in a large scale multi-static network of meteor radar transmitters and receivers. This would, for example, provide higher spatio-temporal resolution for mesospheric wind field measurements.

  9. Database of Properties of Meteors

    NASA Technical Reports Server (NTRS)

    Suggs, Rob; Anthea, Coster

    2006-01-01

    A database of properties of meteors, and software that provides access to the database, are being developed as a contribution to continuing efforts to model the characteristics of meteors with increasing accuracy. Such modeling is necessary for evaluation of the risk of penetration of spacecraft by meteors. For each meteor in the database, the record will include an identification, date and time, radiant properties, ballistic coefficient, radar cross section, size, density, and orbital elements. The property of primary interest in the present case is density, and one of the primary goals in this case is to derive densities of meteors from their atmospheric decelerations. The database and software are expected to be valid anywhere in the solar system. The database will incorporate new data plus results of meteoroid analyses that, heretofore, have not been readily available to the aerospace community. Taken together, the database and software constitute a model that is expected to provide improved estimates of densities and to result in improved risk analyses for interplanetary spacecraft. It is planned to distribute the database and software on a compact disk.

  10. Structure of the Chesapeake Bay Impact Crater from Wide-Angle Seismic Waveform Tomography

    NASA Astrophysics Data System (ADS)

    Lester, W. R.; Hole, J. A.; Catchings, R. D.; Bleibinhaus, F.

    2006-12-01

    The 35 million year old Chesapeake Bay impact structure is one of the largest and most well preserved meteor/comet impact structures on Earth. As a marine impact on a continental shelf, its morphology consists of a deep inner crater penetrating pre-existing crystalline basement surrounded by a much wider, shallower crater within the overlying sediments. In 2004, the U.S. Geological Survey conducted a combined refraction and low-fold reflection seismic survey across the northern part of the inner crater with the goals of constraining crater structure and identifying an ideal drill site for a deep borehole. Waveform inversion was applied to the seismic data to produce a high-resolution seismic velocity model of the inner crater. This significantly improved the spatial resolution over previous images based on travel times. Under the northeastern part of the outer crater, eastward-sloping, relatively intact crystalline basement is at a depth of ~1.5 km. The edge of the inner crater is at ~17 km radius and slopes gradually inward to penetrate pre-existing crystalline basement. The top of crystalline rock on the central uplift is about 0.8 km higher than its surroundings. Seismic velocity of crystalline rocks under the inner crater is much lower than under the outer crater, suggesting strong fracturing/brecciation of the inner crater floor and even stronger brecciation of the central uplift. A basement uplift and lateral change of basement velocity occurs at a radius of ~12 km and is interpreted as possibly indicating the edge of the transient crater caused by impact excavation prior to collapse. Assuming a 24 km diameter transient crater, scaling laws based on extraterrestrial craters and numerical models predict the observed inner crater diameter, central uplift diameter, and inner crater depth. This suggests that the crater collapse processes that created the inner crater in crystalline rocks were unaffected by the much weaker rheology of the overlying sediments.

  11. A Bright Lunar Impact Flash Linked to the Virginid Meteor Complex

    NASA Technical Reports Server (NTRS)

    Moser, D. E.; Suggs, R. M.; Suggs, R. J.

    2015-01-01

    Since early 2006, NASA's Marshall Space Flight Center (MSFC) has observed over 330 impact flashes on the Moon, produced by meteoroids striking the lunar surface. On 17 March 2013 at 03:50:54.312 UTC, the brightest flash of a 9-year routine observing campaign was observed by two 0.35 m telescopes at MSFC. The camera onboard the Lunar Reconnaissance Orbiter (LRO), a NASA spacecraft mapping the Moon from lunar orbit, discovered the fresh crater associated with this impact [1] approximately 3 km from the location predicted by a newly developed geolocation technique [2]. The meteoroid impactor responsible for this event may have been part of a stream of large particles encountered by the Earth/Moon associated with the Virginid Meteor Complex, as evidenced by a cluster of five fireballs seen in Earth's atmosphere on the same night by the NASA All Sky Fireball Network [3] and the Southern Ontario Meteor Network [4]. Crater size calculations based on assumptions derived from fireball measurements yielded an estimated crater diameter of 10-23 m rim-to-rim using the Holsapple [5] and Gault [6] models, a result consistent with the observed crater measured to be 18 m across. This is the first time a lunar impact flash has been associated with fireballs in Earth's atmosphere and an observed crater.

  12. A fast meteor detection algorithm

    NASA Astrophysics Data System (ADS)

    Gural, P.

    2016-01-01

    A low latency meteor detection algorithm for use with fast steering mirrors had been previously developed to track and telescopically follow meteors in real-time (Gural, 2007). It has been rewritten as a generic clustering and tracking software module for meteor detection that meets both the demanding throughput requirements of a Raspberry Pi while also maintaining a high probability of detection. The software interface is generalized to work with various forms of front-end video pre-processing approaches and provides a rich product set of parameterized line detection metrics. Discussion will include the Maximum Temporal Pixel (MTP) compression technique as a fast thresholding option for feeding the detection module, the detection algorithm trade for maximum processing throughput, details on the clustering and tracking methodology, processing products, performance metrics, and a general interface description.

  13. Rampart Crater Ejecta

    NASA Technical Reports Server (NTRS)

    2004-01-01

    [figure removed for brevity, see original site]

    Released 25 May 2004 This image of rampart crater ejecta was acquired Feb. 16, 2003, during northern summer.

    The THEMIS VIS camera is capable of capturing color images of the martian surface using its five different color filters. In this mode of operation, the spatial resolution and coverage of the image must be reduced to accommodate the additional data volume produced from the use of multiple filters. To make a color image, three of the five filter images (each in grayscale) are selected. Each is contrast enhanced and then converted to a red, green, or blue intensity image. These three images are then combined to produce a full color, single image. Because the THEMIS color filters don't span the full range of colors seen by the human eye, a color THEMIS image does not represent true color. Also, because each single-filter image is contrast enhanced before inclusion in the three-color image, the apparent color variation of the scene is exaggerated. Nevertheless, the color variation that does appear is representative of some change in color, however subtle, in the actual scene. Note that the long edges of THEMIS color images typically contain color artifacts that do not represent surface variation.

    Image information: VIS instrument. Latitude 45.9, Longitude 347 East (13 West). 38 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D

  14. Cratered Acidalia Planitia

    NASA Technical Reports Server (NTRS)

    2005-01-01

    [figure removed for brevity, see original site]

    The THEMIS VIS camera is capable of capturing color images of the Martian surface using five different color filters. In this mode of operation, the spatial resolution and coverage of the image must be reduced to accommodate the additional data volume produced from using multiple filters. To make a color image, three of the five filter images (each in grayscale) are selected. Each is contrast enhanced and then converted to a red, green, or blue intensity image. These three images are then combined to produce a full color, single image. Because the THEMIS color filters don't span the full range of colors seen by the human eye, a color THEMIS image does not represent true color. Also, because each single-filter image is contrast enhanced before inclusion in the three-color image, the apparent color variation of the scene is exaggerated. Nevertheless, the color variation that does appear is representative of some change in color, however subtle, in the actual scene. Note that the long edges of THEMIS color images typically contain color artifacts that do not represent surface variation.

    This false color image shows a region with craters of different ages located at the margin of Acidalia Planitia. This iamge was collected during the Northern Spring season.

    Image information: VIS instrument. Latitude 39.9, Longitude 350.4 East (9.6 West). 38 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey

  15. Acidalia Planitia Crater

    NASA Technical Reports Server (NTRS)

    2004-01-01

    [figure removed for brevity, see original site]

    Released 24 May 2004 This image of a crater in Acidalia Planitia was acquired Sept. 29, 2002, during northern spring.

    The THEMIS VIS camera is capable of capturing color images of the martian surface using its five different color filters. In this mode of operation, the spatial resolution and coverage of the image must be reduced to accommodate the additional data volume produced from the use of multiple filters. To make a color image, three of the five filter images (each in grayscale) are selected. Each is contrast enhanced and then converted to a red, green, or blue intensity image. These three images are then combined to produce a full color, single image. Because the THEMIS color filters don't span the full range of colors seen by the human eye, a color THEMIS image does not represent true color. Also, because each single-filter image is contrast enhanced before inclusion in the three-color image, the apparent color variation of the scene is exaggerated. Nevertheless, the color variation that does appear is representative of some change in color, however subtle, in the actual scene. Note that the long edges of THEMIS color images typically contain color artifacts that do not represent surface variation.

    Image information: VIS instrument. Latitude 49.6, Longitude 325.3 East (34.7 West). 38 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science

  16. Acidalia Planitia Crater

    NASA Technical Reports Server (NTRS)

    2004-01-01

    [figure removed for brevity, see original site]

    Released 26 May 2004 This image of a crater in Acidalia Planitia was acquired March 8, 2003, during northern summer.

    The THEMIS VIS camera is capable of capturing color images of the martian surface using its five different color filters. In this mode of operation, the spatial resolution and coverage of the image must be reduced to accommodate the additional data volume produced from the use of multiple filters. To make a color image, three of the five filter images (each in grayscale) are selected. Each is contrast enhanced and then converted to a red, green, or blue intensity image. These three images are then combined to produce a full color, single image. Because the THEMIS color filters don't span the full range of colors seen by the human eye, a color THEMIS image does not represent true color. Also, because each single-filter image is contrast enhanced before inclusion in the three-color image, the apparent color variation of the scene is exaggerated. Nevertheless, the color variation that does appear is representative of some change in color, however subtle, in the actual scene. Note that the long edges of THEMIS color images typically contain color artifacts that do not represent surface variation.

    Image information: VIS instrument. Latitude 45.9, Longitude 6.1 East (353.9 West). 38 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science

  17. Nili Fossae Crater

    NASA Technical Reports Server (NTRS)

    2004-01-01

    [figure removed for brevity, see original site]

    Released 17 May 2004 This image of a crater near Nili Fossae was acquired July 31, 2002, during northern spring.

    The THEMIS VIS camera is capable of capturing color images of the martian surface using its five different color filters. In this mode of operation, the spatial resolution and coverage of the image must be reduced to accommodate the additional data volume produced from the use of multiple filters. To make a color image, three of the five filter images (each in grayscale) are selected. Each is contrast enhanced and then converted to a red, green, or blue intensity image. These three images are then combined to produce a full color, single image. Because the THEMIS color filters don't span the full range of colors seen by the human eye, a color THEMIS image does not represent true color. Also, because each single-filter image is contrast enhanced before inclusion in the three-color image, the apparent color variation of the scene is exaggerated. Nevertheless, the color variation that does appear is representative of some change in color, however subtle, in the actual scene. Note that the long edges of THEMIS color images typically contain color artifacts that do not represent surface variation.

    Image information: VIS instrument. Latitude 21.2, Longitude 75.6 East (284.4 West). 38 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington

  18. Non-linear meteor trails

    NASA Astrophysics Data System (ADS)

    Beech, Martin

    1988-08-01

    In this essay an attempt is made to not only review but reopen the debate on nonlinear meteor trails. On the basis of data culled from various, now historical, sources it is found that approximately one in every two hundred of the visual meteors is likely to show a nonlinear trail, and that of such trails about 60 percent will be continuously curved and 40 percent sinusoidal. It is suggested that two mechanisms may explain the various trail types: the continuously curved trails being a manifestation of the classical Magnus effect, and the sinusoidal trails resulting from torque-free precession.

  19. Wake in faint television meteors

    NASA Technical Reports Server (NTRS)

    Robertson, M. C.; Hawkes, Robert L.

    1992-01-01

    The two component dustball model was used in numerical lag computation. Detached grain lag is typically less than 2 km, with expected wakes of a few hundred meters. True wake in television meteors is masked by apparent wake due to the combined effects of image persistence and blooming. To partially circumvent this problem, we modified a dual MCP intensified CID video system by addition of a rotating shutter to reduce the effective exposure time to about 2.0 ms. Preliminary observations showed that only 2 of 27 analyzed meteors displayed statistically significant wake.

  20. Meteor Shower Identification and Characterization with Python

    NASA Technical Reports Server (NTRS)

    Moorhead, Althea

    2015-01-01

    The short development time associated with Python and the number of astronomical packages available have led to increased usage within NASA. The Meteoroid Environment Office in particular uses the Python language for a number of applications, including daily meteor shower activity reporting, searches for potential parent bodies of meteor showers, and short dynamical simulations. We present our development of a meteor shower identification code that identifies statistically significant groups of meteors on similar orbits. This code overcomes several challenging characteristics of meteor showers such as drastic differences in uncertainties between meteors and between the orbital elements of a single meteor, and the variation of shower characteristics such as duration with age or planetary perturbations. This code has been proven to successfully and quickly identify unusual meteor activity such as the 2014 kappa Cygnid outburst. We present our algorithm along with these successes and discuss our plans for further code development.

  1. Global Variation of Meteor Trail Plasma Turbulence

    NASA Technical Reports Server (NTRS)

    Dyrud, L. P.; Hinrichs, J.; Urbina, J.

    2011-01-01

    We present the first global simulations on the occurrence of meteor trail plasma irregularities. These results seek to answer the following questions: when a meteoroid disintegrates in the atmosphere will the resulting trail become plasma turbulent, what are the factors influencing the development of turbulence, and how do they vary on a global scale. Understanding meteor trail plasma turbulence is important because turbulent meteor trails are visible as non-specular trails to coherent radars, and turbulence influences the evolution of specular radar meteor trails, particularly regarding the inference of mesospheric temperatures from trail diffusion rates, and their usage for meteor burst communication. We provide evidence of the significant effect that neutral atmospheric winds and density, and ionospheric plasma density have on the variability of meteor trail evolution and the observation of nonspecular meteor trails, and demonstrate that trails are far less likely to become and remain turbulent in daylight, explaining several observational trends using non-specular and specular meteor trails.

  2. The making of meteor astronomy: part V.

    NASA Astrophysics Data System (ADS)

    Beech, M.

    1993-12-01

    The first true comparisons between the observations and the "rising vapors" hypothesis of meteor origins were made in the early eighteenth century. One of the key figures in the new meteoric dialogue was Edmond Halley.

  3. Note on the 1972 Giacobinid meteor shower.

    NASA Technical Reports Server (NTRS)

    Harvey, G. A.

    1973-01-01

    It is shown that the 1972 Giacobinid meteor shower was extremely weak with a peak activity of two to three visual meteors per hour. Only two meteor spectra were obtained from the 17 slitless spectrograph systems operated by the Langley Research Center. The largely unexpected, essentially null results of the 1972 Giacobinid meteor shower observations are indicative of the present limited understanding and predictability of cosmic dust storms.

  4. The IAU Meteor Shower Nomenclature Rules

    NASA Astrophysics Data System (ADS)

    Jenniskens, Peter

    2008-06-01

    The International Astronomical Union at its 2006 General Assembly in Prague has adopted a set of rules for meteor shower nomenclature, a working list with designated names (with IAU numbers and three-letter codes), and established a Task Group for Meteor Shower Nomenclature in Commission 22 (Meteors and Interplanetary Dust) to help define which meteor showers exist from well defined groups of meteoroids from a single parent body.

  5. Redefinition of the meteor storm from the point of view of spaceflight security

    NASA Astrophysics Data System (ADS)

    Ma, Yuehua; Xu, Pinxin; Li, Guangyu

    ZHR∗ is defined as number of meteoroids passing 1000 km2 zenith area per hour which can produce craters no less than 1 cm in diameter on an aluminum material. The relationship between ZHR and ZHR∗ is deduced. We evaluate the strong meteor showers since 1990s by ZHR∗ instead of ZHR and find the Giacobinid (Draconid) shower in 1998 is much stronger than the Leonid shower in 1999, 2001 and 2002.

  6. The new July meteor shower

    NASA Astrophysics Data System (ADS)

    Zoladek, Przemyslaw; Wisniewski, Mariusz

    2012-12-01

    A new meteor stream was found after an activity outburst observed on 2005 July 15. The radiant was located five degrees west of the possible early Perseid radiant, close to the star Zeta Cassiopeiae. Numerous bright meteors and fireballs were observed during this maximum. Analysis of the IMO Video Database and the SonotaCo orbital database revealed an annual stream which is active just before the appearance of the first Perseids, with a clearly visible maximum at solar longitude 113°1. Activity of the stream was estimated as two times higher than activity of the Alpha Capricornids at the same time. The activity period extends from July 12 to 17, during maximum the radiant is visible at coordinates alpha = 5°9, delta = +50°5, and observed meteors are fast, with Vg = 57.4 km/s. The shower was reported to the IAU Meteor Data Center and recognized as a new discovery. According to IAU nomenclature the new stream should be named the Zeta Cassiopeiids (ZCS). %z Arlt R. (1992). WGN, Journal of the IMO, 20:2, 62-69. Drummond J. D. (1981). Icarus, 45, 545-553. Kiraga M. and Olech A. (2001). In Arlt R., Triglav M., and Trayner C., editors, Proceedings of the International Meteor Conference, Pucioasa, Romania, 21-24 September 2000, pages 45-51. IMO. Molau S. (2007). In Bettonvil F. and Kac J., editors, Proceedings of the International Meteor Conference, Roden, The Netherlands, 14-17 September 2006, pages 38-55. IMO. Molau S. and Rendtel J. (2009). WGN, Journal of the IMO, 37:4, 98-121. Olech A., Zoladek P., Wisniewski M., Krasnowski M., Kwinta M., Fajfer T., Fietkiewicz K., Dorosz D., Kowalski L., Olejnik J., Mularczyk K., and Zloczewski K. (2006). In Bastiaens L., Verbert J., Wislez J.-M., and Verbeeck C., editors, Proceedings of the International Meteor Conference, Oostmalle, Belgium, 15-18 September 2005, pages 53-62. IMO. Poleski R. and Szaruga K. (2006). In Bastiaens L., Verbert J., Wislez J.-M., and Verbeeck C., editors, Proceedings of the International Meteor

  7. Meteor radiant mapping with MU radar

    NASA Technical Reports Server (NTRS)

    Watanabe, Jun-Ichi; Nakamura, Tsuko; Tsuda, T.; Tsutsumi, M.; Miyashita, A.; Yoshikawa, M.

    1992-01-01

    The radiant point mapping of meteor showers with the MU radar by using a modified mapping method originally proposed by Morton and Jones (1982) was carried out. The modification is that each meteor echo was weighted by using the beam pattern of the radar system. A preliminary result of the radiant point mapping of the Geminids meteor shower in 1989 is presented.

  8. New trends in meteor radio receivers

    NASA Astrophysics Data System (ADS)

    Rault, Jean-Louis

    2014-01-01

    Recent progresses in low cost—but performing—SDR (software defined radio) technology presents a major breakthrough in the domain of meteor radio observations. Their performances are now good enough for meteor work and should therefore encourage newcomers to join the meteor radio community.

  9. Croatian Meteor Network: Ongoing work 2015 - 2016

    NASA Astrophysics Data System (ADS)

    Šegon, D.; Vida, D.; Korlević, K.; Andreić, Ž.

    2016-01-01

    Ongoing work of the Croatian Meteor Network (CMN) between the 2015 and 2016 International Meteor Conferences is presented. The current sky coverage is considered, software updates and updates of orbit catalogues are described. Furthermore, the work done on meteor shower searches, international collaborations as well as new fields of research are discussed. Finally, the educational efforts made by the CMN are described.

  10. Automated Crater Delineation

    NASA Astrophysics Data System (ADS)

    Marques, J. S.; Pina, P.

    2015-05-01

    An algorithm to delineate impact craters based on Edge Maps and Dynamic Programming is presented. The global performance obtained on 1045 craters from Mars (5 m to about 200 km in diameter), achieved 96% of correct contour delineations.

  11. Cratering on Asteroids

    NASA Astrophysics Data System (ADS)

    Marchi, S.; Chapman, C. R.; Barnouin, O. S.; Richardson, J. E.; Vincent, J.-B.

    Impact craters are a ubiquitous feature of asteroid surfaces. On a local scale, small craters puncture the surface in a way similar to that observed on terrestrial planets and the Moon. At the opposite extreme, larger craters often approach the physical size of asteroids, thus globally affecting their shapes and surface properties. Crater measurements are a powerful means of investigation. Crater spatial and size distributions inform us of fundamental processes, such as asteroid collisional history. A paucity of craters, sometimes observed, may be diagnostic of mechanisms of erasure that are unique on low-gravity asteroids. Byproducts of impacts, such as ridges, troughs, and blocks, inform us of the bulk structure. In this chapter we review the major properties of crater populations on asteroids visited by spacecraft. In doing so we provide key examples to illustrate how craters affect the overall shape and can be used to constrain asteroid surface ages, bulk properties, and impact-driven surface evolution.

  12. Meteor Beliefs Project: Meteors in the Maori astronomical traditions of New Zealand

    NASA Astrophysics Data System (ADS)

    Britton, Tui R.; Hamacher, Duane W.

    2014-02-01

    We review the literature for perceptions of meteors in the Maori culture of Aotearoa or New Zealand. We examine representations of meteors in religion, story, and ceremony. We find that meteors are sometimes personified as gods or children, or are seen as omens of death and destruction. The stories we found highlight the broad perception of meteors found throughout the Maori culture, and note that some early scholars conflated the terms comet and meteor.

  13. Meteors by radio: Getting started

    NASA Astrophysics Data System (ADS)

    Lonc, William

    1999-02-01

    A system for detecting meteors by radio is described which is simple and reliable, and thought to be suitable as a science fair project. There is a relatively detailed discussion of the various factors involved in such a project, along with some typical results to indicate the kind of data that is possible.

  14. SPA Meteor Section Results: 2008

    NASA Astrophysics Data System (ADS)

    McBeath, Alastair

    2013-10-01

    A report based on meteor data analyses from 2008 performed by the SPA Meteor Section is given with some discussion. Items detailed comprise: the Quadrantid peak on January 4 which may have had an unusual dip in activity partway through; the Perseid maximum, which seemed to produce two peaks, by far the strongest-recorded of which was around 02h UT on August 13; a meteor outburst on September 9 probably due to the September epsilon-Perseids, for which the radio results suggested activity was present at a stronger level for longer than previous visual and video findings had supposed, perhaps with more than one maximum; another stronger than expected return from the Orionids during October, part of the sequence of unusual events begun in 2006; a fresh Taurid ``swarm'' return in late October to early November, which probably produced somewhat higher activity than normal, if without the increased bright-meteor component observed at some previous returns; strong Leonid activity later in November, from the radio reports, possibly with two peaks; a Geminid maximum in December which showed some curious discrepancies between the limited visual and radio observations; and the Ursids, which may have provided another moderately-enhanced return, with up to four potential peaks recorded by radio observations in the first twelve hours UT of December 22.

  15. Chasing Meteors With a Microscope.

    ERIC Educational Resources Information Center

    Jones, Richard C.

    1993-01-01

    Describes types of meteors and micrometeorites that enter the Earth's atmosphere. Presents an activity where students collect micrometeorites with a strip of tape in an undisturbed outdoor area. After 24 hours, they examine the tape by sandwiching it between 2 glass slides and view through a microscope at 100X. (PR)

  16. The Merna, Nebraska Meteorite Crater

    NASA Astrophysics Data System (ADS)

    Povenmire, H.

    1995-09-01

    significant raised rim. The nature of contour plowing would reduce any present rim by pulling the raised portion down into the crater. The crater has an average diameter of 5400 feet at the 2950 ft. elevation contour. The crater is elliptical with an eccentricity of approximately 0.71. It is oriented with the major axis at an azimuth of 45 degrees. The minimum age for this crater is approximately 3000 years as determined by one Carbon 14 sample [2]. This was probably a witnessed event as Pawnee Indian legends are rich in phenomena which may relate to this event. In the area surrounding the crater for several km are at least 12 secondary craters. Some of these have a diameter of 550 m. These are distinct from the eolian features by their circular shape and distribution from the primary crater. A 6.8 kg (H4) chondrite was found in the proximity [3]. It has a specific gravity of 3.5. Several magnetic spherules of probable extraterrestrial origin and large quantities of glass flakes have been found in the crater area. Approximately 60 quartz grains were examined by polarizing microscope and about half showed some shocking. There is an active search program for more meteorites in the area. A bore hole to search for breccia and shatter cones is planned. The "IMPACI" software was developed to simulate and model this projectile using the "average" entry velocity of Near Earth Asteroids of 21.8 km per second. The best solutions suggest an approximately 195 m diameter NEA entering the atmosphere and creating an air blast at approximately 8 km altitude. The kinetic energy would have been equivalent to 180 megatons of TNT of which approximately 50 percent would have been absorbed by the atmosphere [4] [5]. References: [1] Dort W. et al. (1992) GSA, 24, 196. [2] Dort W. (1993) personal communication. [3] Graham A. et al. (1985) Catalogue of Meteorites, 4th edition, p. 82, Univ. of Arizona. [4] Chyba C. et al. (1993) Nature, 361, 40-44. [5] Hills J. and Goda M. (1993) Astrophys. J., 105

  17. COBRA meteor radar antenna designs

    NASA Astrophysics Data System (ADS)

    Zainuddin, Mohamad

    A meteor radar system is one of the effective remote sensing techniques in measuring atmospheric parameters such as wind velocities, temperature, pressure and density which are essential in understanding the atmospheric dynamics in the Mesosphere Lower Thermosphere (MLT) region. Previous studies of very high frequency (VHF) meteors radar systems suggest that the minimum error for the estimation of the horizontal wind velocity from a radar interferometry algorithm should occur when the main beams of the transmit and receive antennas are pointing to between 30° to 50° elevation angles. Therefore, an ideal antenna design for VHF meteor radar systems would produce a pencil beam radiation pattern at a 45° elevation angle. However, both the transmit and receive antenna of the COBRA meteor radar system have major beams are pointing to between 60° to 65° degree elevation angles above a perfect ground plane. Besides transmitting maximum power at low elevation angles, the current antennas of the COBRA meteor radar are highly dependent on the ground plane to radiate maximum gains to between 60° to 65° degree elevation angles. Typically, the earth ground is considered as a common ground plane for many VHF antenna with acceptable performance. However, the earth ground could not effectively reflect most of the power at all time. Because the antennas are dependent on ground to radiate power at certain direction, an artificial ground plane or ground screen has to be built for the COBRA antenna system at the South Pole station, which is located on top of more than 2000 meter thick of ice sheet. This dissertation focuses on the analysis of the performance of the individual current antenna design with four different conditions namely in free space, above an infinite ground, lossy ground and finite ground. In the analysis of finite ground, the effects of varying wire spacing and the size of finite ground to the radiation pattern of a cross folded dipole antenna are investigated

  18. New survey of meteor showers

    NASA Astrophysics Data System (ADS)

    Jenniskens, P.

    2014-07-01

    In order to confirm the many showers listed in the IAU Working List of Meteor Showers in need of verification, a 60-camera three-station video surveillance of the night sky is being conducted in the San Francisco Bay Area in California (http://cams.seti.org), called the Cameras for Allsky Meteor Surveillance (CAMS) project [1]. Now, the first 2.5 years of observations were reduced and analyzed, comprised of 112,024 meteoroid trajectories from mostly +4 to -2 magnitude meteors. The trajectories were calculated with a mean precision of 0.24° in radiant direction and 2 % in speed. An interactive tool was developed to study the distribution of meteoroid radiant and speed after correction for Earth's motion around the Sun. A report was submitted for publication in Icarus [2]. Our team assigned 30,801 meteors to 320 showers (27.5 %). This included 72 established showers and 64 known but now confirmed showers. An additional 24 previously reported showers were tentatively detected, but need further study. This study adds 105 potential new showers and 23 newly identified components of established showers to the IAU Working List of Meteor Showers. Another 32 showers previously reported based all or in part on CAMS data were detected again. The Northern and Southern Taurids, especially, are found to be composed of a series of individual streams. In this presentation, I will summarize statistical aspects of these shower detections and their relation to parent body near-Earth objects to shed light on the role of mostly dormant comets in contributing dust to the inner solar system.

  19. San Francisco Volcanic Field, Arizona, as AN Analog for Lunar and Martian Surface Exploration

    NASA Astrophysics Data System (ADS)

    Young, K. E.; Hodges, K.; Eppler, D.; Horz, F.; Lofgren, G. E.; Hurtado, J. M.; Desert Rats Science Team

    2010-12-01

    Terrestrial analog sites are an important tool that planetary geologists and engineers can use to examine both the geologic processes that shape other planetary surfaces as well as to develop and test technologies that are needed for the exploration of planetary surfaces. During the Apollo era, sites like Meteor Crater, Arizona, were used to train astronauts in the protocols and practices of field geology so that their lunar surface activities would be more geologically productive and efficient. As we enter a new period of planetary surface exploration, analogs will be increasingly important in preparing the next generation of both human and robotic planetary explorers. No single analog will be representative of another planetary surface, but testing technologies in a variety of settings will provide NASA and other space agencies with the operational knowledge needed to launch exploratory missions. The site we present here is one of many that can be used to explore surface operations on other planetary surfaces. The San Francisco Volcanic Field (SFVF), containing both SP Crater and Black Point Lava Flow (BPLF), Arizona, is currently being used as the test site for the Desert Research and Technology Studies (D-RATS) field test, coordinated by Johnson Space Center (JSC) and involving several other NASA centers. During the 2010 test, two habitat rovers (Space Exploration Vehicles, or SEVs) operated simultaneously, each with one astronaut crewmember and one geologist crewmember. The mission lasted 14 days and traversed some 150 km. The geologic setting of SFVF includes a series of ~2 Ma basaltic lava flows overlying Triassic sedimentary rocks, both among the predominant rock types that are found primarily on Mars. SFVF has also been identified as an analog to the Marius Hills on the Moon, a Constellation site of interest. In addition, D-RATS 2010 is simulating operational scenarios based on notional traverses near the Malapert Massif on the lunar surface. While SFVF is

  20. Meteors Without Borders: a global campaign

    NASA Astrophysics Data System (ADS)

    Heenatigala, T.

    2012-01-01

    "Meteors Without Borders" is a global project, organized by Astronomers Without Borders and launched during the Global Astronomy Month in 2010 for the Lyrid meteor shower. The project focused on encouraging amateur astronomy groups to hold public outreach events for major meteor showers, conduct meteor-related classroom activities, photography, poetry and art work. It also uses social-media platforms to connect groups around the world to share their observations and photography, live during the events. At the International Meteor Conference 2011, the progress of the project was presented along with an extended invitation for collaborations for further improvements of the project.

  1. Degraded Crater Rim

    NASA Technical Reports Server (NTRS)

    2002-01-01

    (Released 3 May 2002) The Science The eastern rim of this unnamed crater in Southern Arabia Terra is very degraded (beaten up). This indicates that this crater is very ancient and has been subjected to erosion and subsequent bombardment from other impactors such as asteroids and comets. One of these later (younger) craters is seen in the upper right of this image superimposed upon the older crater rim material. Note that this smaller younger crater rim is sharper and more intact than the older crater rim. This region is also mantled with a blanket of dust. This dust mantle causes the underlying topography to take on a more subdued appearance. The Story When you think of Arabia, you probably think of hot deserts and a lot of profitable oil reserves. On Mars, however, Southern Arabia Terra is a cold place of cratered terrain. This almost frothy-looking image is the badly battered edge of an ancient crater, which has suffered both erosion and bombardment from asteroids, comets, or other impacting bodies over the long course of its existence. A blanket of dust has also settled over the region, which gives the otherwise rugged landscape a soft and more subdued appearance. The small, round crater (upper left) seems almost gemlike in its setting against the larger crater ring. But this companionship is no easy romance. Whatever formed the small crater clearly whammed into the larger crater rim at some point, obliterating part of its edge. You can tell the small crater was formed after the first and more devastating impact, because it is laid over the other larger crater. How much younger is the small one? Well, its rim is also much sharper and more intact, which gives a sense that it is probably far more youthful than the very degraded, ancient crater.

  2. Impact craters on Titan

    USGS Publications Warehouse

    Wood, Charles A.; Lorenz, Ralph; Kirk, Randy; Lopes, Rosaly; Mitchell, Karl; Stofan, Ellen; Cassini RADAR Team

    2010-01-01

    Five certain impact craters and 44 additional nearly certain and probable ones have been identified on the 22% of Titan's surface imaged by Cassini's high-resolution radar through December 2007. The certain craters have morphologies similar to impact craters on rocky planets, as well as two with radar bright, jagged rims. The less certain craters often appear to be eroded versions of the certain ones. Titan's craters are modified by a variety of processes including fluvial erosion, mass wasting, burial by dunes and submergence in seas, but there is no compelling evidence of isostatic adjustments as on other icy moons, nor draping by thick atmospheric deposits. The paucity of craters implies that Titan's surface is quite young, but the modeled age depends on which published crater production rate is assumed. Using the model of Artemieva and Lunine (2005) suggests that craters with diameters smaller than about 35 km are younger than 200 million years old, and larger craters are older. Craters are not distributed uniformly; Xanadu has a crater density 2-9 times greater than the rest of Titan, and the density on equatorial dune areas is much lower than average. There is a small excess of craters on the leading hemisphere, and craters are deficient in the north polar region compared to the rest of the world. The youthful age of Titan overall, and the various erosional states of its likely impact craters, demonstrate that dynamic processes have destroyed most of the early history of the moon, and that multiple processes continue to strongly modify its surface. The existence of 24 possible impact craters with diameters less than 20 km appears consistent with the Ivanov, Basilevsky and Neukum (1997) model of the effectiveness of Titan's atmosphere in destroying most but not all small projectiles.

  3. Impact craters on Titan

    USGS Publications Warehouse

    Wood, C.A.; Lorenz, R.; Kirk, R.; Lopes, R.; Mitchell, Ken; Stofan, E.

    2010-01-01

    Five certain impact craters and 44 additional nearly certain and probable ones have been identified on the 22% of Titan's surface imaged by Cassini's high-resolution radar through December 2007. The certain craters have morphologies similar to impact craters on rocky planets, as well as two with radar bright, jagged rims. The less certain craters often appear to be eroded versions of the certain ones. Titan's craters are modified by a variety of processes including fluvial erosion, mass wasting, burial by dunes and submergence in seas, but there is no compelling evidence of isostatic adjustments as on other icy moons, nor draping by thick atmospheric deposits. The paucity of craters implies that Titan's surface is quite young, but the modeled age depends on which published crater production rate is assumed. Using the model of Artemieva and Lunine (2005) suggests that craters with diameters smaller than about 35 km are younger than 200 million years old, and larger craters are older. Craters are not distributed uniformly; Xanadu has a crater density 2-9 times greater than the rest of Titan, and the density on equatorial dune areas is much lower than average. There is a small excess of craters on the leading hemisphere, and craters are deficient in the north polar region compared to the rest of the world. The youthful age of Titan overall, and the various erosional states of its likely impact craters, demonstrate that dynamic processes have destroyed most of the early history of the moon, and that multiple processes continue to strongly modify its surface. The existence of 24 possible impact craters with diameters less than 20 km appears consistent with the Ivanov, Basilevsky and Neukum (1997) model of the effectiveness of Titan's atmosphere in destroying most but not all small projectiles. ?? 2009 Elsevier Inc.

  4. Recent Advances in Video Meteor Photometry

    NASA Technical Reports Server (NTRS)

    Swift, Wesley R.; Suggs, Robert M.; Meachem, Terry; Cooke, William J.

    2003-01-01

    One of the most common (and obvious) problems with video meteor data involves the saturation of the output signal produced by bright meteors, resulting in the elimination of such meteors from photometric determinations. It is important to realize that a "bright" meteor recorded by intensified meteor camera is not what would be considered "bright" by a visual observer - indeed, many Generation II or III camera systems are saturated by meteors with a visual magnitude of 3, barely even noticeable to the untrained eye. As the relatively small fields of view (approx.30 ) of the camera systems captures at best modest numbers of meteors, even during storm peaks, the loss of meteors brighter than +3 renders the determination of shower population indices from video observations even more difficult. Considerable effort has been devoted by the authors to the study of the meteor camera systems employed during the Marshall Space Flight Center s Leonid ground-based campaigns, and a calibration scheme has been devised which can extend the useful dynamic range of such systems by approximately 4 magnitudes. The calibration setup involves only simple equipment, available to amateur and professional, and it is hoped that use of this technique will make for better meteor photometry, and move video meteor analysis beyond the realm of simple counts.

  5. Determination of the Meteor Limiting Magnitude

    NASA Technical Reports Server (NTRS)

    Kingery, A.; Blaauw, R.; Cooke, W. J.

    2016-01-01

    The limiting meteor magnitude of a meteor camera system will depend on the camera hardware and software, sky conditions, and the location of the meteor radiant. Some of these factors are constants for a given meteor camera system, but many change between meteor shower or sporadic source and on both long and short timescales. Since the limiting meteor magnitude ultimately gets used to calculate the limiting meteor mass for a given data set, it is important to have an understanding of these factors and to monitor how they change throughout the night, as a 0.5 magnitude uncertainty in limiting magnitude translates to a uncertainty in limiting mass by a factor of two.

  6. Extraterrestrial meteors: a martian meteor and its parent comet.

    PubMed

    Selsis, Franck; Lemmon, Mark T; Vaubaillon, Jérémie; Bell, James F

    2005-06-01

    Regular meteor showers occur when a planet approaches the orbit of a periodic comet--for example, the Leonid shower is evident around 17 November every year as Earth skims past the dusty trail of comet Tempel-Tuttle. Such showers are expected to occur on Mars as well, and on 7 March last year, the panoramic camera of Spirit, the Mars Exploration Rover, revealed a curious streak across the martian sky. Here we show that the timing and orientation of this streak, and the shape of its light curve, are consistent with the existence of a regular meteor shower associated with the comet Wiseman-Skiff, which could be characterized as martian Cepheids. PMID:15931208

  7. Martian doublet craters.

    NASA Technical Reports Server (NTRS)

    Oberbeck, V. R.; Aoyagi, M.

    1972-01-01

    A large number of Mars craters are nearly tangential to other craters. They occur in clusters or as isolated crater doublets. Results of probability calculations and a Monte Carlo cratering simulation model show conclusively that many of the Mars craters could not have resulted from random single-body impact. The possibility that these craters are calderas is considered possible only if calderas on Mars form by mechanisms different from those on earth. However, clusters and doublets could be caused by meteoroid breakup resulting from stresses induced in the meteoroid by the gravitational field of Mars. It is concluded that, under certain conditions, doublets should be produced on Mars as a direct result of breakup of an impacting meteoroid. The impact process can yield nonrandom crater distributions that should be observed in different degrees of development on different planetary surfaces.

  8. High temperature condensates among meteors

    NASA Technical Reports Server (NTRS)

    Wilkening, L. L.

    1975-01-01

    It is noted that two meteors which exhibited no lines of iron or sodium in their spectra have been tentatively attributed to aubrites in order to explain their lack of iron. It is shown, however, that no meteorites, including aubrites, have simultaneously low abundances of iron and sodium and that possible parent materials other than aubrites must be considered for the observed meteors. Other possible parent materials considered in this letter include melilite and diopside, two minerals containing both Ca and Mg but neither Fe nor Na. It is suggested that meteoroids rich in Ca and Mg but lacking Fe and Na might form a reservoir for the so-called 'lost' elements (Ca, Mg, Al, Ti, the lanthanides, and other refractory elements) which are depleted in ordinary and enstatite chondrites relative to cosmic abundances.

  9. Artificial meteor ablation studies: Olivine

    NASA Technical Reports Server (NTRS)

    Blanchard, M. B.; Cunningham, G. G.

    1973-01-01

    Artificial meteor ablation was performed on a Mg-rich olivine sample using an arc-heated plasma of ionized air. Experimental conditions simulated a meteor traveling about 12 km/sec at an altitude of 70 km. The mineral content of the original olivine sample was 98% olivine (including traces of olivine alteration products) and 2% chromite. Forsterite content of the original olivine was Fo-89. After ablation, the forsterite content had increased to Fo-94 in the recrystallized olivine. In addition, lamella-like intergrowths of magnetite were prevalent constituents. Wherever magnetite occurred, there was an increase in Mg and a corresponding decrease in Fe for the recrystallized olivine. The Allende fusion crust consisted of a recrystallized olivine, which was more Mg-rich and Fe-deficient than the original meteorite's olivine, and abundant magnetite grains. Although troilite and pentlandite were the common opaque mineral constituents in this meteorite, magnetite was the principal opaque mineral found in the fusion crust.

  10. The ALTAIR Meteor Measurements Program

    NASA Technical Reports Server (NTRS)

    Cooke, William J.

    2007-01-01

    Established in late 2006, the Meteor Measurements Program is in the process of using the ALTAIR radar located on Kwajelein Atoll to obtain radar observations of sporadic and shower meteoroids. The goals are to determine meteoroid masses, orbits, ballistic coefficients and densities, which shall be provided to the Meteoroid Environment Office (MEO) at Marshall Space Flight Center. These data and analyses shall then be used by the MEO to 1) Add a realistic density distribution to the new Meteoroid Engineering Model (MEM), which is the specified environment for vehicle design in the NASA Constellation (return to Moon) program. This program is the implementation of President Bush's Vision for Space Exploration (VSE). 2) Investigate the meteoroid velocity distribution at smaller masses. 3) Strive to understand the differences (biases) in meteoroid observations produced by systems like ALTAIR and those of the meteor patrol radars, such as the University of Western Ontario's CMOR system. This paper outlines the program details and its progress.

  11. Z-model analysis of impact cratering - An overview

    NASA Technical Reports Server (NTRS)

    Austin, M. G.; Thomsen, J. M.; Ruhl, S. F.; Orphal, D. L.; Borden, W. F.; Larson, S. A.; Schultz, P. H.

    1981-01-01

    The Maxwell Z-Model has been applied to two continuum mechanics computer calculations: (1) a laboratory-scale impact of an aluminum projectile into plasticene clay, and (2) a planetary-scale impact of an iron meteor into gabbroic anorthosite. The material flow in the cratering flow field may be well approximated by incompressible flow for most of the excavation stage of crater growth. The center of the flow field is located beneath, not at, the surface. Soon after energy partitioning is complete, Z can assume values less than 2.0 associated with the initial directedness of the projectile's momentum. The Z-Model parameters are time dependent during a significant portion of the crater growth time, and Z increases steadily with time from about 2.0 or slightly less at the beginning of the excavation stage to level off at values in the neighborhood of about 3.0 before the excavation stage is half-over.

  12. Meteor observations under the INASAN supervision

    NASA Astrophysics Data System (ADS)

    Kartashova, A. P.; Bagrov, A. V.

    2012-09-01

    Meteor observations have the specific property: we do not know in advance neither area on the celestial sphere, not the time when the event occurs. Besides that, a meteor flash in the atmosphere has duration few seconds or less, and it is hard problem to gather enough photons from it to register a faint or fast meteor. There are a number of tasks in meteor astronomy for solution of which not only a simple registration of meteors in the optical range is required, but a high spatial and time resolution as well. Television method is the most acceptable for such a case and is widely used in the practice of meteor observations. Television meteor observations in Russia are carried out under the Institute of Astronomy of the Russian Academy of Sciences (INASAN) supervision in different regions of Russia: Moscow region, Irkutsk, Ryazan and North Caucasus. The TV system PatrolCa designed for observations in the wide field of view (the ordinary for most of meteor cameras), consists of the following components: the high resolution cameras Watec LCL-902HS, the wide-angle photograph objectives Canon 6/0.8 (F=6 mm, the aperture 1:0.8). The cameras have fields of view of 50°x40° and have a limiting magnitude (for meteors) of +4 m ÷ +5 m. The FAVOR (FAst Variability Optical Registrator) camera is used for observations of faint meteors at the North Caucasus [1]. The basic components of this camera are the following: the high-aperture lense objective with the aperture 150 mm and the focal length 180mm (the aperture 1:1.2), the image intensifier, the objective reversal, CCD receiver "Videoscan" VS-СTT285 2001. The CCD "Sony" ICX285 has format 1380 х 1024 pixels. The camera has a field of view of 18 ° х 20°, and has a limiting magnitude of above +10m (for meteors). The two cameras similar to FAVOR (named SMAC) were designed for double-station observations of faint meteors. The results of observations at these cameras are presented. The observations were held by both methods

  13. Kharkiv Meteor Radar System (the XX Age)

    NASA Astrophysics Data System (ADS)

    Kolomiyets, S. V.

    2012-09-01

    Kharkiv meteor radar research are of historic value (Kolomiyets and Sidorov 2007). Kharkiv radar observations of meteors proved internationally as the best in the world, it was noted at the IAU General Assembly in 1958. In the 1970s Kharkiv meteor automated radar system (MARS) was recommended at the international level as a successful prototype for wide distribution. Until now, this radar system is one of the most sensitive instruments of meteor radars in the world for astronomical observations. In 2004 Kharkiv meteor radar system is included in the list of objects which compose the national property of Ukraine. Kharkiv meteor radar system has acquired the status of the important historical astronomical instrument in world history. Meteor Centre for researching meteors in Kharkiv is a analogue of the observatory and performs the same functions of a generator and a battery of special knowledge and skills (the world-famous studio). Kharkiv and the location of the instrument were brand points on the globe, as the place where the world-class meteor radar studies were carried out. They are inscribed in the history of meteor astronomy, in large letters and should be immortalized on a world-wide level.

  14. Meteor velocity determination with plasma physics

    NASA Astrophysics Data System (ADS)

    Dyrud, L. P.; Denney, K.; Close, S.; Oppenheim, M.; Chau, J.; Ray, L.

    2004-06-01

    Understanding the global meteor flux at Earth requires the measurement of meteor velocities. While several radar methods exist for measuring meteor velocity, they may be biased by plasma reflection mechanisms. This paper presents a new method for deriving meteoroid velocity from the altitudinal extent of non-specular trails. This method employs our recent discoveries on meteor trail plasma instability. Dyrud et al. (2002) demonstrated that meteor trails are unstable over a limited altitude range, and that the precise altitudes of instability are dependent on the meteoroid that generated the trail. Since meteor trail instability results in field aligned irregularities (FAI) that allow for radar reflection, non-specular trail observations may be used to derive velocity. We use ALTAIR radar data of combined head echos and non-specular trails to test non-specular trail derived velocity against head echo velocities. Meteor velocities derived from non-specular trail altitudinal width match to within 5 km/s when compared with head echo range rates from the same meteor. We apply this technique to Piura radar observations of hundreds of non-specular trails to produce histograms of occurrence of meteor velocity based solely on this non-specular trails width criterion. The results from this study show that the most probable velocity of meteors seen by the Piura radar is near 50 km/s, which is comparable with modern head echo studies.

  15. Meteor velocity determination with plasma physics

    NASA Astrophysics Data System (ADS)

    Dyrud, L. P.; Denney, K.; Close, S.; Oppenheim, M.; Ray, L.; Chau, J.

    2004-02-01

    Understanding the global meteor flux at Earth requires the measurement of meteor velocities. While several radar methods exist for measuring meteor velocity, they may be biased by plasma reflection mechanisms. This paper presents a new method for deriving meteoroid velocity from the altitudinal extent of non-specular trails. This method employs our recent discoveries on meteor trail plasma instability. Dyrud et al. (2002) demonstrated that meteor trails are unstable over a limited altitude range, and that the precise altitudes of instability are dependent on the meteoroid velocity that generated the trail. Since meteor trail instability results in field aligned irregularities (FAI) that allow for radar reflection, non-specular trail observations may be used to derive velocity. We use ALTAIR radar data of combined head echos and non-specular trails to test non-specular trail derived velocity against head echo velocities. Meteor velocities derived from non-specular trail altitudinal width match to within 5 km/s when compared with head echo range rates from the same meteor. We apply this technique to Piura radar observations of hundreds of non-specular trails to produce histograms of occurrence of meteor velocity based solely on this non-specular trails width criterion. The results from this study show that the most probable velocity of meteors seen by the Piura radar is near 50 km/s which is comparable with modern head echo studies.

  16. Meteor burst communications improvement study

    NASA Astrophysics Data System (ADS)

    Peterson, David

    1993-07-01

    Two identical Meteor Burst Radio Terminals were developed, fabricated, and delivered to the Air Force. Each is controlled by a PC computer in a menu driven manner. The mode of operation is full duplex. The RF frequency range is 40 to 60 MHz with tuning increments of 25 KHz. Data rates are 4, 8, 16, 32, 64, 128, 256, and 512 kbps. Modulation is coherent Binary Phase Shift Keying (BPSK) and incoherent Differential Phase Shift Keying (DPSK). Protocol includes Automatic Repeat Request (ARQ) with source and destination addressing, message number, start of message, and end of message. Messages are packetized, and Reed Solomon (R-S) coding is an option. The ARQ is under the control of a Cyclic Redundancy Check Code (CRCC) which detects binary errors within each packet. The terminal is intended to increase meteor trail availability and data throughput by several orders of magnitude--by operating with new antennas that provide much higher gains without sacrificing meteor trail acquisition performance.

  17. Simulated Craters on Venus

    NASA Technical Reports Server (NTRS)

    Zahnle, Kevin; Cuzzi, Jeffrey N. (Technical Monitor)

    1995-01-01

    The thick atmosphere of Venus prevents all but the largest impactors from cratering the surface. The number of small craters on Venus provides an interesting, and statistically significant test of models for the disruption and deceleration of impacting bodies. Here we compare Monte Carlo simulated crater distributions to the observed crater distribution on Venus. The simulation assumes: (1) a power law mass distribution for impactors of the form N(sub cum) alpha m (exp-b) where b=0.8; (2) isotropic incidence angles; (3) velocity at the top of the atmosphere of 20 kilometers per second (more realistic velocity distributions are also considered); (4) Schmidt-Housen crater scaling, modified such that only the normal component of the impact velocity contributes to cratering, and using crater slumping as parameterized (5) and modern populations (60% carbonaceous, 40% stone, 3% iron) and fluxes of asteroids. We use our previously developed model for the disruption and deceleration of large bodies striking thick planetary atmospheres to calculate the impact velocity at the surface as a function of impactor mass, incident velocity, and incident angle. We use a drag coefficient c(sub d) =1; other parameters are as described in Chyba et al. We set a low velocity cutoff of 500 meters per second on crater-forming impacts. Venus's craters are nicely matched by the simulated craters produced by 700 million years of striking asteroids. Shown for comparison are the simulated craters produced by incident comets over the same period, where for comets we have assumed b=0.7 and a flux at 10(exp 14) g 30% that of asteroids. Systematic uncertainties in crater scaling and crater slumping may make the surface age uncertain by a factor of two.

  18. Impact craters on Venus

    NASA Technical Reports Server (NTRS)

    Schaber, G. G.

    1991-01-01

    Compared with volcanism and tectonism, impact cratering on Venus has played an overall minor role in sculpting the present-day landscape. The study of Venus impact craters is vital to help place the chronology of the geologic features on the surface in the context of the planet's geological evolution. The degradation of impact craters also provides information on surface and interior processes, particularly alteration by tectonism and volcanism. Through orbit 1422, Magellan mapped about 450 impact craters, with diameters ranging from 2 to 275 km, within an area of about 226 million sq km, or 49 percent of the planet's surface. These craters and their associated deposits show surprisingly little evidence of degradation at the 75 m/pixel resolution of the Magellan SAR. Remarkably few craters in the Magellan images appear to be in the process of being buried by volcanic deposits or destroyed by tectonic activity.

  19. Layers in Crater Cluster

    NASA Technical Reports Server (NTRS)

    2003-01-01

    MGS MOC Release No. MOC2-431, 24 July 2003

    This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a cluster of old, small impact craters near 36.3oN, 281.9oW. The group of craters was probably formed by secondary impacts following a much larger impact that occurred some distance away; the material that created these craters would have been the ejecta from the larger crater, rather than meteoroids from outer space. The craters cluster is considered to be relatively old because none of the craters have ejecta blankets any more, and each was filled, or partially filled, with layered material that was later eroded to form the terraced mounds found in their floors. This picture is illuminated from the lower left.

  20. The Upsilon Pegasid Meteor Shower

    NASA Astrophysics Data System (ADS)

    Povenmire, H.

    1995-09-01

    On the morning of August 8, 1975, meteors were observed from a previously unrecognized radiant in Pegasus. The rates were approximately seven per hour [1]. The radiant was alpha = 350 degrees, delta = +19 degrees (2000.0). These meteors are characterized as swift, yellow-white and without significant ionization trains [1]. The average magnitude of several hundred meteors from this shower is approximately +3.50, slightly fainter than the Perseids which occur at the same time. A broad maximum seems to occur about August 8. The three active fireball networks (Prairie, MORP and European) were contacted in a search for previously recorded fireballs with negative results. Ceplecha [2] of the European Network computed the orbital elements using the FIRBAL program. On August 19, 1982 at 02:09:57 UT, a magnitude -14.76 f1reball occurred over the White Carpathian Mountains of Austria and Czechoslovakia. It was photographed by five cameras of the European Network. Reduction of this Upsilon Pegasid fireball (EN 190882A) showed it to be a type IIIb fireball [2] - that is, an extremely low density, cometary, snow-like material with a specific gravity of approximately 0.27 g/cm^3. This material ablates at high altitude and cannot produce sonic phenomena or meteorites. It is similar to the material in the Draconid meteor shower. The orbital elements derived from EN 190882A are given in Table I. Table I: Orbital elements for the Upsilon Pegasid stream from EN 190882A. omega = 305.9009 degrees Omega = 145.3431 degrees i = 85.0817 degrees q = 0.2022 e = 1.0 velocity = 51.8608 km/s Using these refined elements, Kronk [3] computed the radiant drift. The radiant drifts from the SSW to NNE at a relatively steep angle and at an average rate of 20 arc-min per day. An intensive literature search [3] revealed four double station Upsilon Pegasids which had previously been listed as sporadics. Institutions providing these data were Yale [4], Stalinabad [5], Tadjikistan [6] and Harvard [7

  1. Big data era in meteor science

    NASA Astrophysics Data System (ADS)

    Vinković, D.; Gritsevich, M.; Srećković, V.; Pečnik, B.; Szabó, G.; Debattista, V.; Škoda, P.; Mahabal, A.; Peltoniemi, J.; Mönkölä, S.; Mickaelian, A.; Turunen, E.; Kákona, J.; Koskinen, J.; Grokhovsky, V.

    2016-01-01

    Over the last couple of decades technological advancements in observational techniques in meteor science have yielded drastic improvements in the quality, quantity and diversity of meteor data, while even more ambitious instruments are about to become operational. This empowers meteor science to boost its experimental and theoretical horizons and seek more advanced science goals. We review some of the developments that push meteor science into the big data era that requires more complex methodological approaches through interdisciplinary collaborations with other branches of physics and computer science. We argue that meteor science should become an integral part of large surveys in astronomy, aeronomy and space physics, and tackle the complexity of micro-physics of meteor plasma and its interaction with the atmosphere.

  2. Testing Crater Counting Assumptions with the Cratered Terrain Evolution Model

    NASA Astrophysics Data System (ADS)

    Minton, D. A.; Richardson, J. E.; Fassett, C. I.

    2015-05-01

    Using CTEM to answer the questions; 1) How close to Poisson-distributed are crater count uncertainties? and 2) How does observed clustering in crater count densities of large craters relate to the changes in the impactor flux?

  3. Crater Rays on Ganymede

    NASA Technical Reports Server (NTRS)

    1997-01-01

    This mosaic of Voyager 2 images taken July 9, 1979, shows a prominent rayed crater on Jupiter's icy moon, Ganymede. The view on the left is a monochrome image, and that on the right is the same scene shown in false color designed to accentuate the icy ejecta rays splashed out by the impact. This crater is about 150 km (93 miles) across. Like several other large craters in this scene, the rayed one has a central pit, whose origins remain speculative but may involve impact melting or solid-state fluidization of the icy crust. Bright crater rays on Ganymede, like those on our own Moon, are useful to geologists because they constitute a set of features that were laid across the moon's surface at a discrete point in time--thus they serve as time markers that can be used to establish the sequence of events that shaped Ganymede's surface. For instance, the crater rays appear to be painted over, hence are younger than, areas of grooved terrain (lower left quadrant), whereas a somewhat smaller crater at the center of the scene has icy ejecta that appears to bury (hence, post-dates) the large crater ray system. One can conclude that the grooved terrain formed first, then the large crater and its rays, and then the smaller crater and its fresh icy ejecta deposits.

  4. Bi-telescopic, deep, simultaneous meteor observations

    NASA Technical Reports Server (NTRS)

    Taff, L. G.

    1986-01-01

    A statistical summary is presented of 10 hours of observing sporadic meteors and two meteor showers using the Experimental Test System of the Lincoln Laboratory. The observatory is briefly described along with the real-time and post-processing hardware, the analysis, and the data reduction. The principal observational results are given for the sporadic meteor zenithal hourly rates. The unique properties of the observatory include twin telescopes to allow the discrimination of meteors by parallax, deep limiting magnitude, good time resolution, and sophisticated real-time and post-observing video processing.

  5. Experimental impact crater morphology

    NASA Astrophysics Data System (ADS)

    Dufresne, A.; Poelchau, M. H.; Hoerth, T.; Schaefer, F.; Thoma, K.; Deutsch, A.; Kenkmann, T.

    2012-04-01

    The research group MEMIN (Multidisciplinary Experimental and Impact Modelling Research Network) is conducting impact experiments into porous sandstones, examining, among other parameters, the influence of target pore-space saturation with water, and projectile velocity, density and mass, on the cratering process. The high-velocity (2.5-7.8 km/s) impact experiments were carried out at the two-stage light-gas gun facilities of the Fraunhofer Institute EMI (Germany) using steel, iron meteorite (Campo del Cielo IAB), and aluminium projectiles with Seeberg Sandstone as targets. The primary objectives of this study within MEMIN are to provide detailed morphometric data of the experimental craters, and to identify trends and characteristics specific to a given impact parameter. Generally, all craters, regardless of impact conditions, have an inner depression within a highly fragile, white-coloured centre, an outer spallation (i.e. tensile failure) zone, and areas of arrested spallation (i.e. spall fragments that were not completely dislodged from the target) at the crater rim. Within this general morphological framework, distinct trends and differences in crater dimensions and morphological characteristics are identified. With increasing impact velocity, the volume of craters in dry targets increases by a factor of ~4 when doubling velocity. At identical impact conditions (steel projectiles, ~5km/s), craters in dry and wet sandstone targets differ significantly in that "wet" craters are up to 76% larger in volume, have depth-diameter ratios generally below 0.19 (whereas dry craters are almost consistently above this value) at significantly larger diameters, and their spallation zone morphologies show very different characteristics. In dry craters, the spall zone surfaces dip evenly at 10-20° towards the crater centre. In wet craters, on the other hand, they consist of slightly convex slopes of 10-35° adjacent to the inner depression, and of sub-horizontal tensile

  6. Sand Sheet on Crater Floor

    NASA Technical Reports Server (NTRS)

    2005-01-01

    [figure removed for brevity, see original site]

    Our topic for the weeks of April 4 and April 11 is dunes on Mars. We will look at the north polar sand sea and at isolated dune fields at lower latitudes. Sand seas on Earth are often called 'ergs,' an Arabic name for dune field. A sand sea differs from a dune field in two ways: 1) a sand sea has a large regional extent, and 2) the individual dunes are large in size and complex in form.

    As with yesterday's image, this dune field is located inside a crater, in this case an unnamed crater at 26 degrees North latitude. In this VIS image the dunes are coalescing into a sand sheet, note the lack of dune forms to the north of the small hills. The presence of ridges and hills in the area is affecting the dune shapes.

    Image information: VIS instrument. Latitude 26.4, Longitude 62.7 East (297.3 West). 19 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology

  7. Gale Crater in IR Color

    NASA Technical Reports Server (NTRS)

    2004-01-01

    [figure removed for brevity, see original site]

    Released August 4, 2004 This image shows two representations of the same infra-red image of Gale Crater. On the left is a grayscale image showing surface temperature, and on the right is a false-color composite made from 3 individual THEMIS bands. The false-color image is colorized using a technique called decorrelation stretch (DCS), which emphasizes the spectral differences between the bands to highlight compositional variations.

    In the bottom of the crater, surrounding the central mound, there are extensive basaltic sand deposits. The basaltic sand spectral signature combined with the warm surface (due to the low albedo of basaltic sand) produces a very strong pink/magenta color. This color signature contrasts with the green/yellow color of soil and dust in the top of the image, and the cyan color due to the presence of water ice clouds at the bottom of the image. This migrating sand may be producing the erosional features seen on the central mound.

    Image information: IR instrument. Latitude -4.4, Longitude 137.4 East (222.6 West). 100 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University

  8. Basaltic Crater in Color IR

    NASA Technical Reports Server (NTRS)

    2004-01-01

    [figure removed for brevity, see original site]

    Released August 6, 2004 This image shows two representations of the same infra-red image near Nili Fosse in the the Isidis region of Mars. On the left is a grayscale image showing surface temperature, and on the right is a false-color composite made from 3 individual THEMIS bands. The false-color image is colorized using a technique called decorrelation stretch (DCS), which emphasizes the spectral differences between the bands to highlight compositional variations. In many cases craters trap sand in their topographic depressions, interrupting the sand's migration across the Martian surface. This image is particularly interesting because there appears to be more than 1 type of sand in the bottom of this crater and in the hummocky terrain near the bottom of the image. The pink/magenta areas are characteristic of a basaltic composition, but there are also orange areas that are likely caused by the presence of andesite. These two compositions, basalt and andesite, are some of the most common found on Mars.

    Image information: IR instrument. Latitude 24, Longitude 80.7 East (297.3 West). 100 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip

  9. Impact and cratering rates onto Pluto

    NASA Astrophysics Data System (ADS)

    Greenstreet, Sarah; Gladman, Brett; McKinnon, William B.

    2015-09-01

    The New Horizons spacecraft fly-through of the Pluto system in July 2015 will provide humanity's first data for the crater populations on Pluto and its binary companion, Charon. In principle, these surfaces could be dated in an absolute sense, using the observed surface crater density (# craters/km2 larger than some threshold crater diameter D). Success, however, requires an understanding of both the cratering physics and absolute impactor flux. The Canada-France Ecliptic Plane Survey (CFEPS) L7 synthetic model of classical and resonant Kuiper belt populations (Petit, J.M. et al. [2011]. Astron. J. 142, 131-155; Gladman, B. et al. [2012]. Astron. J. 144, 23-47) and the scattering object model of Kaib et al. (Kaib, N., Roškar, R., Quinn, T. [2011]. Icarus 215, 491-507) calibrated by Shankman et al. (Shankman, C. et al. [2013]. Astrophys. J. 764, L2-L5) provide such impact fluxes and thus current primary cratering rates for each dynamical sub-population. We find that four sub-populations (the q < 42AU hot and stirred main classicals, the classical outers, and the plutinos) dominate Pluto's impact flux, each providing ≈ 15-25 % of the total rate. Due to the uncertainty in how the well-characterized size distribution for Kuiper belt objects (with impactor diameter d > 100km) connects to smaller projectiles, we compute cratering rates using five model impactor size distributions: a single power-law, a power-law with a knee, a power-law with a divot, as well as the "wavy" size distributions described in Minton et al. (Minton, D.A. et al. [2012]. Asteroids Comets Meteors Conf. 1667, 6348) and Schlichting et al. (Schlichting, H.E., Fuentes, C.I., Trilling, D.E. [2013]. Astron. J. 146, 36-42). We find that there is only a small chance that Pluto has been hit in the past 4 Gyr by even one impactor with a diameter larger than the known break in the projectile size distribution (d ≈ 100km) which would create a basin on Pluto (D ⩾ 400km in diameter). We show that due to

  10. 'Endurance Crater' Overview

    NASA Technical Reports Server (NTRS)

    2004-01-01

    This overview of 'Endurance Crater' traces the path of the Mars Exploration Rover Opportunity from sol 94 (April 29, 2004) to sol 205 (August 21, 2004). The route charted to enter the crater was a bit circuitous, but well worth the extra care engineers took to ensure the rover's safety. On sol 94, Opportunity sat on the edge of this impressive, football field-sized crater while rover team members assessed the scene. After traversing around the 'Karatepe' region and past 'Burns Cliff,' the rover engineering team assessed the possibility of entering the crater. Careful analysis of the angles Opportunity would face, including testing an Earth-bound model on simulated martian terrain, led the team to decide against entering the crater at that particular place. Opportunity then backed up before finally dipping into the crater on its 130th sol (June 5, 2004). The rover has since made its way down the crater's inner slope, grinding, trenching and examining fascinating rocks and soil targets along the way. The rover nearly made it to the intriguing dunes at the bottom of the crater, but when it got close, the terrain did not look safe enough to cross.

  11. Investigating the effects of target heterogeneity on the cratering process.

    NASA Astrophysics Data System (ADS)

    Barnouin, O. S.

    2012-12-01

    Pre-existing target structures are known to influence the dynamics and morphologies of many terrestrial and planetary impact craters. Good examples include the Chesapeake and Ries craters, which both possess an inverted sombrero structure as a result of a weaker sedimentary surface layer overlying a stronger crystalline basement. But beyond such horizontal layering, closer analyses of the subsurface geology present in these and other planetary craters indicate that vertical heterogeneity in the strength and geochemistry of a target are also often present. These may influence the formation and subsequent modification of terrestrial craters. Evidence indicates that at Meteor crater, for example, pre-existing vertical jointing of the target gives this crater its square appearance, either by confining and re-directing the shock and subsequent rarefraction waves, or by allowing preferential weathering zones of weakness along the joints. In this study, we present a series of laboratory investigations and 2- and 3-dimensional numerical calculations of crater formation in a conceptually simple but physically complex target: a box of randomly distributed quartz spheres of identical size. These investigations provide constraints on how all types of target heterogeneity influence the cratering process. In both the laboratory and numerical studies, we measure the rate of crater growth, the transient crater shape, and in some instances the velocity of individual ejecta. These investigations vary the ratio of the impact shock thickness to target grain size by altering the impact velocity, projectile size, and target grain size. The laboratory data were collected at the NASA Ames vertical gun range, the NASA Johnson Space Center vertical gun range, and the University of Tokyo vertical gun range using non-intrusive diagonistic techniques. The numerical investigations were performed using the CTH hydrocode that solves the equations of motion, while conserving mass, energy, and

  12. Centrifuge Impact Cratering Experiments

    NASA Technical Reports Server (NTRS)

    Schmidt, R. M.; Housen, K. R.; Bjorkman, M. D.

    1985-01-01

    The kinematics of crater growth, impact induced target flow fields and the generation of impact melt were determined. The feasibility of using scaling relationships for impact melt and crater dimensions to determine impactor size and velocity was studied. It is concluded that a coupling parameter determines both the quantity of melt and the crater dimensions for impact velocities greater than 10km/s. As a result impactor radius, a, or velocity, U cannot be determined individually, but only as a product in the form of a coupling parameter, delta U micron. The melt volume and crater volume scaling relations were applied to Brent crater. The transport of melt and the validity of the melt volume scaling relations are examined.

  13. Report of centimeter-sized tektites in Pima County, Arizona, cannot be verified

    NASA Technical Reports Server (NTRS)

    Kring, David A.; Hildebrand, Alan R.; Drake, Michael J.; Melosh, H. Jay; Vickery, Ann M.

    1995-01-01

    Glassy objects reportedly found in Pima County, Arizona, have been identified as tektites. A field survey of the area where they were said to occur, however, did not produce any other tektites, nor did it reveal any other geologic features that might indicate a nearby impact crater. The major-, minor-, and trace-element composition of one specimen is similar to those measured in indochinites, which suggests the objects reportedly from Pima County were instead transported to southern Arizona from Indochina by people.

  14. Meteor spectra in the EDMOND database

    NASA Astrophysics Data System (ADS)

    Koukal, J.; Gorková, S.; Srba, J.; Ferus, M.; Civiš, S.; di Pietro, C. A.

    2015-01-01

    We present a selection of five interesting meteor spectra obtained in the years 2014 and 2015 via CCTV video systems with a holographic grating, working in CEMENT and BRAMON meteor observation networks. Based on the EDMOND multi stations video meteor trajectory data an orbital classification of these meteors was performed. Selected meteors are members of the LYR, SPE, DSA and LVI meteor streams, one meteor is classified as sporadic background (SPO). In calibrated spectra the main chemical components were identified. Meteors are chemically classified based on relative intensities of the main spectral lines (or multiplets): Mg I (2), Na I (1), and Fe I (15). Bolide EN091214 is linked with the 23rd meteorite with known orbit (informally known as "Žďár"), two fragments of the parent body were found in the Czech Republic so far (August, 2015). For this particular event a time resolved spectral observation and comparison with laboratory spectra of LL3.2 chondritic meteorite are presented.

  15. The Makings of Meteor Astronomy: Part XIII

    NASA Astrophysics Data System (ADS)

    Beech, M.

    1996-10-01

    In 1848, Sir John Lubbock advanced the hypothesis that meteors shine by reflected sunlight. He developed a set of equations describing the geometry of meteor encounters, and for a decade or so, his idea was at least marginally supported by other observers.

  16. Croatian Meteor Network: ongoing work 2014 - 2015

    NASA Astrophysics Data System (ADS)

    Šegon, D.; Andreić, Ž.; Korlević, K.; Vida, D.

    2015-01-01

    Ongoing work mainly between 2014-2015 International Meteor Conferences (IMC) has been presented. Current sky coverage, software updates, orbit catalogues updates, shower search updates, international collaboration as well as new fields of research and educational efforts made by the Croatian Meteor Network are described.

  17. Meteor Terminology poster translated into different languages

    NASA Astrophysics Data System (ADS)

    Perlerin, Vincent; Hankey, Mike

    2014-02-01

    The American Meteor Society (AMS) has created an educational poster that defines the major terms of the meteor terminology. This poster is an educational tool made available for free on the AMS website. We offer this poster to be translated and shared among the IMO members.

  18. Crater in the Mangala Valles Region

    NASA Technical Reports Server (NTRS)

    2003-01-01

    [figure removed for brevity, see original site]

    Released 26 May 2003

    Just south of the 2 km high main mass of the Medusae Fossae Formation, in a region dissected by channels, lies an unnamed crater that may have been filled by mud. A channel spills into this crater on its eastern side and may have delivered the material that now covers the floor of the crater. The subdued ridges may be wrinkle ridges in a preexisting lava flow that are now covered by a layer of sediment. The cracked surface is evidence for the subsequent deposition of mud.

    Image information: VIS instrument. Latitude -6, Longitude 206.7 East (153.3 West). 19 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  19. The geology and mechanics of formation of the Fort Rock Dome, Yavapai County, Arizona

    USGS Publications Warehouse

    Fuis, Gary S.

    1996-01-01

    The Fort Rock Dome, a craterlike structure in northern Arizona, is the erosional product of a circular domal uplift associated with a Precambrian shear zone exposed within the crater and with Tertiary volcanism. A section of Precambrian to Quaternary rocks is described, and two Tertiary units, the Crater Pasture Formation and the Fort Rock Creek Rhyodacite, are named. A mathematical model of the doming process is developed that is consistent with the history of the Fort Rock Dome.

  20. Northern Arizona Volcanoes

    NASA Technical Reports Server (NTRS)

    2006-01-01

    Northern Arizona is best known for the Grand Canyon. Less widely known are the hundreds of geologically young volcanoes, at least one of which buried the homes of local residents. San Francisco Mtn., a truncated stratovolcano at 3887 meters, was once a much taller structure (about 4900 meters) before it exploded some 400,000 years ago a la Mt. St. Helens. The young cinder cone field to its east includes Sunset Crater, that erupted in 1064 and buried Native American homes. This ASTER perspective was created by draping ASTER image data over topographic data from the U.S. Geological Survey National Elevation Data.

    With its 14 spectral bands from the visible to the thermal infrared wavelength region, and its high spatial resolution of 15 to 90 meters (about 50 to 300 feet), ASTER images Earth to map and monitor the changing surface of our planet.

    ASTER is one of five Earth-observing instruments launched December 18, 1999, on NASA's Terra satellite. The instrument was built by Japan's Ministry of Economy, Trade and Industry. A joint U.S./Japan science team is responsible for validation and calibration of the instrument and the data products.

    The broad spectral coverage and high spectral resolution of ASTER provides scientists in numerous disciplines with critical information for surface mapping, and monitoring of dynamic conditions and temporal change. Example applications are: monitoring glacial advances and retreats; monitoring potentially active volcanoes; identifying crop stress; determining cloud morphology and physical properties; wetlands evaluation; thermal pollution monitoring; coral reef degradation; surface temperature mapping of soils and geology; and measuring surface heat balance.

    The U.S. science team is located at NASA's Jet Propulsion Laboratory, Pasadena, Calif. The Terra mission is part of NASA's Science Mission Directorate.

    Size: 20.4 by 24.6 kilometers (12.6 by 15.2 miles) Location: 35.3 degrees North latitude, 111

  1. Activity of the Lyrid meteor stream

    NASA Technical Reports Server (NTRS)

    Lindblad, Bertil A.; Porubcan, V.

    1992-01-01

    The activity of the Lyrid meteor stream is in most years fairly low with a visual rate at maximum (21-22 April) of 5-10 meteors per hour. Short bursts of very high Lyrid activity, with visual hourly rates of 100 or more, have sometimes been reported. These observations generally refer to faint visual meteors. The reported bursts of high activity have occurred in a very narrow interval of solar longitudes (deg 31.24 to 31.38 equinox 1950.0), while the recurrent or 'normal' maximum for bright meteors occurs at solar longitude deg 31.6, or slightly later. A mass separation of the meteors in the shower is thus indicated.

  2. On Short-Perihelion Meteor Streams

    NASA Astrophysics Data System (ADS)

    Terentjeva, Alexandra; Bakanas, Elena; Barabanov, Sergey

    2013-02-01

    Research was conducted concerning the relation of short-perihelion meteor streams with comets and asteroids. But the origin of meteor streams with small perihelion distance (of the Arietid and Geminid types) has always represented a special problem for obvious reasons. Over four hundred meteor and fireball streams (by optical and TV-observations) contained 20 streams of perihelion distance q ≤ 0.26 AU. The research shows that 8 of 20 streams displayed a relation with small bodies. No relation was found either with comets or asteroids for the remaining 12 streams. Short-period streams may be formed on quasiparabolic comet orbits with small q in the perihelion area as well. In particular, SOHO comets may be a rich source both of small and large meteor bodies, forming short-perihelion meteor streams among others.

  3. Meteoric activities during the 11th century

    NASA Astrophysics Data System (ADS)

    Ahn, Sang-Hyeon

    2005-04-01

    We have analysed the meteor records in the chronicles that describe the era of the Song dynasty (AD 960-1279). The data are complementary to the record-vacant 10th century of the Koryo dynasty (AD 918-1392). The annual activity of sporadic meteors analysed shows a generic sinusoidal behaviour as in modern observations. In addition, we have also found that there are two prominent meteor showers, one in August and the other in November, appearing on the fluctuating sporadic meteors. The date of occurrence of the August shower indicates it to be the Perseids. By comparing the date of occurrence of the November shower with those of the Leonid showers of the Koryo dynasty, recent visual observations and the world-wide historical meteor storms, we conclude that the November shower is the Leonids. The regression rate of the Leonids is obtained to be days per century, which agrees with recent observations.

  4. Bigger Crater Farther South of 'Victoria' on Mars

    NASA Technical Reports Server (NTRS)

    2008-01-01

    [figure removed for brevity, see original site] Annotated version

    The team operating NASA's Mars Exploration Rover Opportunity has chosen southeast as the direction for the rover's next extended journey, toward a crater more than 20 times wider than 'Victoria Crater.' Opportunity exited Victoria Crater on Aug. 28, 2008, after nearly a year investigating the interior.

    The crater to the southeast is about 22 kilometers (13.7 miles) in diameter and about 300 meters (1,000 feet) deep, exposing a much thicker stack of rock layers than those examined in Victoria Crater.

    The rover team informally calls the bigger crater 'Endeavour' and emphasizes that Opportunity may well never reach it. The rover has already operated more than 18 times longer than originally planned, and the distance to the big crater, about 12 kilometers (7 miles) matches the total distance Opportunity has driven since landing in early 2004. Driving southeastward is expected to take Opportunity to exposures of younger rock layers than is has previously seen and to provide access to rocks on the plain that were thrown long distances by impacts that excavated even deeper, more distant craters.

    The crater that Opportunity will drive toward dominates this orbital view from the Thermal Emission Imaging System (THEMIS) camera on NASA's Mars Odyssey orbiter. The much smaller Victoria Crater is the most prominent circle near the upper left corner of the image. This view is a mosaic of about 50 separate visible-light images taken by THEMIS.

    NASA's Jet Propulsion Laboratory manages the Mars Odyssey and Mars Exploration Rover missions for the NASA Science Mission Directorate, Washington, D.C. THEMIS was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the

  5. Sporadic E-Layers and Meteor Activity

    NASA Astrophysics Data System (ADS)

    Alimov, Obid

    2016-07-01

    In average width it is difficult to explain variety of particularities of the behavior sporadic layer Es ionospheres without attraction long-lived metallic ion of the meteoric origin. Mass spectrometric measurements of ion composition using rockets indicate the presence of metal ions Fe+, Mg+, Si+, Na+, Ca+, K+, Al+ and others in the E-region of the ionosphere. The most common are the ions Fe+, Mg+, Si+, which are primarily concentrated in the narrow sporadic layers of the ionosphere at altitudes of 90-130 km. The entry of meteoric matter into the Earth's atmosphere is a source of meteor atoms (M) and ions (M +) that later, together with wind shear, produce midlatitude sporadic Es layer of the ionosphere. To establish the link between sporadic Es layer and meteoroid streams, we proceeded from the dependence of the ionization coefficient of meteors b on the velocity of meteor particles in different meteoroid streams. We investigated the dependence of the critical frequency f0Es of sporadic E on the particle velocity V of meteor streams and associations. It was established that the average values of f0Es are directly proportional to the velocity V of meteor streams and associations, with the correlation coefficient of 0.53 < R < 0.74. Thus, the critical frequency of the sporadic layer Es increases with the increase of particle velocity V in meteor streams, which indicates the direct influence of meteor particles on ionization of the lower ionosphere and formation of long-lived metal atoms M and ions M+ of meteoric origin.

  6. Effects of Pre-Existing Target Structure on the Formation of Large Craters

    NASA Technical Reports Server (NTRS)

    Barnouin-Jha, O. S.; Cintala, M. J.; Crawford, D. A.

    2003-01-01

    The shapes of large-scale craters and the mechanics responsible for melt generation are influenced by broad and small-scale structures present in a target prior to impact. For example, well-developed systems of fractures often create craters that appear square in outline, good examples being Meteor Crater, AZ and the square craters of 433 Eros. Pre-broken target material also affects melt generation. Kieffer has shown how the shock wave generated in Coconino sandstone at Meteor crater created reverberations which, in combination with the natural target heterogeneity present, created peaks and troughs in pressure and compressed density as individual grains collided to produce a range of shock mineralogies and melts within neighboring samples. In this study, we further explore how pre-existing target structure influences various aspects of the cratering process. We combine experimental and numerical techniques to explore the connection between the scales of the impact generated shock wave and the pre-existing target structure. We focus on the propagation of shock waves in coarse, granular media, emphasizing its consequences on excavation, crater growth, ejecta production, cratering efficiency, melt generation, and crater shape. As a baseline, we present a first series of results for idealized targets where the particles are all identical in size and possess the same shock impedance. We will also present a few results, whereby we increase the complexities of the target properties by varying the grain size, strength, impedance and frictional properties. In addition, we investigate the origin and implications of reverberations that are created by the presence of physical and chemical heterogeneity in a target.

  7. Small volcanic crater near Pavonis Mons (Released 14 November 2002

    NASA Technical Reports Server (NTRS)

    2002-01-01

    [figure removed for brevity, see original site]

    The small crater observed at the middle-right edge of this THEMIS image is very different from other similar looking impact craters located southeast of the Pavonis Mons volcano. This crater appears to be a volcanic crater at the summit of a small composite cone that shows evidence of repeated volcanic flows.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  8. 'Mazatzal' Rock on Crater Rim

    NASA Technical Reports Server (NTRS)

    2004-01-01

    NASA's Spirit took this navigation camera image of the 2-meter-wide (6.6-foot-wide) rock called 'Mazatzal' on sol 76, March 21, 2004. Scientists intend to aggressively analyze this target with Spirit's microscopic imager, Moessbauer spectrometer and alpha particle X-ray spectrometer before brushing and 'digging in' with the rock abrasion tool on upcoming sols.

    Mazatzal stood out to scientists because of its large size, light tone and sugary surface texture. It is the largest rock the team has seen at the rim of the crater informally named 'Bonneville.' It is lighter-toned than previous rock targets Adirondack and Humphrey. Its scalloped pattern may be a result of wind sculpting, a very slow process in which wind-transported silt and sand abrade the rock's surface, creating depressions. This leads scientists to believe that Mazatzal may have been exposed to the wind in this location for an extremely long time.

    The name 'Mazatzal' comes from a mountain range and rock formation that was deposited around 1.2 billion years ago in the Four Peaks area of Arizona.

  9. Craters on comets

    NASA Astrophysics Data System (ADS)

    Vincent, Jean-Baptiste; Oklay, Nilda; Marchi, Simone; Höfner, Sebastian; Sierks, Holger

    2015-03-01

    This paper reviews the observations of crater-like features on cometary nuclei. We compare potential crater sizes and morphologies, and we discuss the probability of impacts between small asteroids in the Main Belt and a comet crossing this region of the Solar System. Finally, we investigate the fate of the impactor and its chances of survival on the nucleus. We find that comets do undergo impacts although the rapid evolution of the surface erases most of the features and make craters difficult to detect. In the case of a collision between a rocky body and a highly porous cometary nucleus, two specific crater morphologies can be formed: a central pit surrounded by a shallow depression, or a pit, deeper than typical craters observed on rocky surfaces. After the impact, it is likely that a significant fraction of the projectile will remain in the crater. During its two years long escort of comet 67P/Churyumov-Gerasimenko, ESA's mission Rosetta should be able to detect specific silicates signatures at the bottom of craters or crater-like features, as evidence of this contamination. For large craters, structural changes in the impacted region, in particular compaction of material, will affect the local activity. The increase of tensile strength can extinct the activity by preventing the gas from lifting up dust grains. On the other hand, material compaction can help the heat flux to travel deeper in the nucleus, potentially reaching unexposed pockets of volatiles, and therefore increasing the activity. Ground truth data from Rosetta will help us infer the relative importance of those two effects.

  10. Venus - Mead Crater

    NASA Technical Reports Server (NTRS)

    1991-01-01

    This Magellan image mosaic shows the largest (275 kilometers in diameter [170 miles]) impact crater known to exist on Venus at this point in the Magellan mission. The crater is located north of Aphrodite Terra and east of Eistla Regio at latitude 12.5 degrees north and longitude 57.4 degrees east, and was imaged during Magellan orbit 804 on November 12, 1990. The Magellan science team has proposed to name this crater Mead, after Margaret Mead, the American Anthropologist (1901- 1978). All Magellan-based names of features on Venus are, of course, only proposed until final approval is given by the International Astronomical Union-Commission on Planetary Nomenclature. Mead is classified as a multi-ring crater with its innermost, concentric scarp being interpreted as the rim of the original crater cavity. No inner peak-ring of mountain massifs is observed on Mead. The presence of hummocky, radar-bright crater ejecta crossing the radar-dark floor terrace and adjacent outer rim scarp suggests that the floor terrace is probably a giant rotated block that is concentric to, but lies outside of, the original crater cavity. The flat, somewhat brighter inner floor of Mead is interpreted to result from considerable infilling of the original crater cavity by impact melt and/or by volcanic lavas. To the southeast of the crater rim, emplacement of hummocky ejecta appears to have been impeded by the topography of preexisting ridges, thus suggesting a very low ground-hugging mode of deposition for this material. Radar illumination on this and all other Magellan image products is from the left to the right in the scene.

  11. Venus - Crater Aurelia

    NASA Technical Reports Server (NTRS)

    1990-01-01

    This Magellan image shows a complex crater, 31.9 kilometers (20 miles) in diameter with a circular rim, terraced walls, and central peaks, located at 20.3 degrees north latitude and 331.8 degrees east longitude. Several unusual features are evidenced in this image: large dark surface up range from the crater; lobate flows emanating from crater ejecta, and very radar-bright ejecta and floor. Aurelia has been proposed to the International Astronomical Union, Subcommittee of Planetary Nomenclature as a candidate name. Aurelia is the mother of Julius Caesar.

  12. Crater with Streak

    NASA Technical Reports Server (NTRS)

    2005-01-01

    20 June 2005 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a crater in the Memnonia region of Mars, around which has formed a wind streak. The bright streak is in the lee of the crater -- that is, it is on the crater's down-wind side. Thus, the winds responsible for the streak blew from the southeast (lower right).

    Location near: 6.7oS, 141.4oW Image width: 3 km (1.9 mi) Illumination from: upper left Season: Southern Spring

  13. One View, Two Craters

    NASA Technical Reports Server (NTRS)

    2004-01-01

    This cylindrical projection was constructed from a sequence of four images taken by the navigation camera onboard the Mars Exploration Rover Opportunity.

    The images were acquired on sol 85 of Opportunity's mission to Meridiani Planum. The camera acquired the images at approximately 14:28 local solar time, or around 6:30 a.m. Pacific Daylight Time, on April 20, 2004.

    The view is from the rover's new location, a region dubbed 'Fram Crater' located some 450 meters (.3 miles) from 'Eagle Crater' and roughly 250 meters (820 feet) from 'Endurance Crater' (upper right).

  14. Arizona Adult Education Standards

    ERIC Educational Resources Information Center

    Arizona Department of Education, 2006

    2006-01-01

    Adult education standards are the cornerstone for quality teaching, quality learning, and quality lives. The Arizona Adult Education Standards Initiative (Standards Initiative) represents a proactive effort by Arizona's adult education community to ensure rigor and consistency in program content and student outcomes for adult learners throughout…

  15. Arizona Charter Schools Handbook.

    ERIC Educational Resources Information Center

    Arizona State Dept. of Education, Phoenix.

    This handbook provides information and materials to assist applicants in preparing an application to establish a charter school in Arizona. The topics discussed reflect the technical requirements of Arizona's charter-school legislation. It does not necessarily reflect the selection requirements or the policies of the State Board of Education, the…

  16. SPA Meteor Section Results: 2007

    NASA Astrophysics Data System (ADS)

    McBeath, Alastair

    2013-08-01

    Information extracted from analyses carried out by the SPA Meteor Section from 2007 is presented and discussed. Events covered include: the radio Quadrantid maximum on January 4; a bright fireball seen from parts of England and imaged from the Netherlands at 19h56m UT on February 6, for which an approximate trajectory was established; radio results from the Lyrids in late April; the Perseid near-peak activity from August and a note on some daylight Perseid observing from Britain using thermal imagers; the radio α-Aurigid maximum on September 1; the Orionid return, which again provided enhanced activity over several consecutive dates in October for visual and radio observers; the radio Leonids, although the probably main peak found visually on November 19 was not recorded thus due to its timing; the typically protracted Geminid maximum period around December 13-15 as observed visually and by radio; and the Ursid outburst, primarily as detected by radio on December 22.

  17. Cratering on Small Bodies: Lessons from Eros

    NASA Astrophysics Data System (ADS)

    Chapman, C. R.

    2003-01-01

    Cratering and regolith processes on small bodies happen continuously as interplanetary debris rains down on asteroids, comets, and planetary satellites. Butthey are very poorly observed and not well understood. On the one hand, we have laboratory experimentation at small scales and we have examination of large impact craters (e.g. Meteor Crater on Earth and imaging of abundant craters on terrestrial planets and outer planet moons). Understanding cratering on bodies of intermediate scales, tens of meters to hundreds of km in size, involves either extrapolation from our understanding of cratering phenomena at very different scales or reliance on very preliminary, incomplete examination of the observational data we now have for a few small bodies. I review the latter information here. It has been generally understood that the role of gravity is greatly diminished for smaller bodies, so a lot of cratering phenomena studied for larger bodies is less applicable. But it would be a mistake to imagine that laboratory experiments on gravitationless rocks (usually at 1 g) are directly applicable, except perhaps to those monolithic Near Earth Asteroids (NEAs) some tens of meters in size that spin very rapidly and can be assumed to be "large bare rocks" with "negative gravity". Whereas it had once been assumed that asteroids smaller than some tens of km diameter would retain little regolith, it is increasingly apparent that regolith and megoregolith processes extend down to bodies only hundreds of meters in size, perhaps smaller. Yet these processes are very different from those that pertain to the Moon, which is our chief prototype of regolith processes. The NEAR Shoemaker spacecraft's studies of Eros provide the best evidence to date about small-body cratering processes, as well as a warning that our theoretical understanding requires anchoring by direct observations. Eros: "Ponds", Paucity of Small Craters, and Other Mysteries. Although Eros is currently largely detached

  18. Shackleton Crater Illumination

    NASA Video Gallery

    Simulated illumination conditions near the lunar South Pole. The 30km x 30km region highlights the Shackleton crater. The movie runs for 28 days, centered on the LCROSS impact date on October 9th, ...

  19. Craters in the Classroom.

    ERIC Educational Resources Information Center

    McArdle, Heather K.

    1997-01-01

    Details an activity in which students create and study miniature impact craters in the classroom. Engages students in making detailed, meaningful observations, drawing inferences, reaching conclusions based on scientific evidence, and designing experiments to test selected variables. (DDR)

  20. Craters and Streaks

    NASA Technical Reports Server (NTRS)

    2006-01-01

    1 April 2006 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows two impact craters of nearly equal size, plus their associated wind streaks. These occur in far eastern Chryse Planitia. The wind streaks point toward the southwest (lower left), indicating that the responsible winds blew from the northeast. One of the two craters is shallower than the other, and has a suite of large, windblown ripples on its floor. The shallower crater with the ripples is probably older than the other, deeper crater.

    Location near: 20.6oN, 30.1oW Image width: 3 km (1.9 mi) Illumination from: lower left Season: Northern Winter

  1. Radio Meteors Observations Techniques at RI NAO

    NASA Astrophysics Data System (ADS)

    Vovk, Vasyl; Kaliuzhnyi, Mykola

    2016-07-01

    The Solar system is inhabited with large number of celestial bodies. Some of them are well studied, such as planets and vast majority of big asteroids and comets. There is one group of objects which has received little attention. That is meteoroids with related to them meteors. Nowadays enough low-technology high-efficiency radio-technical solutions are appeared which allow to observe meteors daily. At RI NAO three methodologies for meteor observation are developed: single-station method using FM-receiver, correlation method using FM-receiver and Internet resources, and single-station method using low-cost SDR-receiver.

  2. The 2014 May Camelopardalid Meteor Shower

    NASA Technical Reports Server (NTRS)

    Cooke, Bill; Moser, Danielle

    2014-01-01

    On May 24, 2014 Earth will encounter multiple streams of debris laid down by Comet 209P LINEAR. This will likely produce a new meteor shower, never before seen. Rates predicted to be from 100 to 1000 meteors per hour between 2 and 4 AM EDT, so we are dealing with a meteor outburst, potentially a storm. Peak rate of 200 per hour best current estimate. Difficult to calibrate models due to lack of past observations. Models indicate mm size particles in stream, so potential risk to Earth orbiting spacecraft.

  3. Cratering evaluations and results

    SciTech Connect

    Church, J.R.

    1993-08-01

    Investigations were performed on the 1-mil ultrasonic aluminum wire bonding process to determine how the interaction of the bonding parameters, ultrasonic power, time, force, and aluminum wire, contribute to cratering (cracking or damage to oxide/passivation layers). Investigations revealed that power, time, and force can interact at levels which can contribute to cratering. The age of the aluminum wire can also influence the quality of bonds.

  4. Har Crater on Callisto

    NASA Technical Reports Server (NTRS)

    1997-01-01

    This image shows a heavily cratered region near Callisto's equator. It was taken by the Galileo spacecraft Solid State Imaging (CCD) system on its ninth orbit around Jupiter. North is to the top of the image. The 50 kilometer (30 mile) double ring crater in the center of the image is named Har. Har displays an unusual rounded mound on its floor. The origin of the mound is unclear but probably involves uplift of ice-rich materials from below, either as a 'rebound' immediately following the impact that formed the crater or as a later process. Har is older than the prominent 20 kilometer (12 mile) crater superposed on its western rim. The large crater partially visible in the northeast corner of the image is called Tindr. Chains of secondary craters (craters formed from the impact of materials thrown out of the main crater during an impact) originating from Tindr crosscut the eastern rim of Har.

    The image, centered at 3.3 degrees south latitude and 357.9 degrees west longitude, covers an area of 120 kilometers by 115 kilometers (75 miles by 70 miles). The sun illuminates the scene from the west (left). The smallest distinguishable features in the image are about 294 meters (973 feet) across. This image was obtained on June 25, 1997, when Galileo was 14,080 kilometers (8,590 miles) from Callisto.

    The Jet Propulsion Laboratory, Pasadena, CA manages the Galileo mission for NASA's Office of Space Science, Washington, DC. JPL is an operating division of California Institute of Technology (Caltech).

    This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://galileo.jpl.nasa.gov.

  5. The First Confirmed Videorecordings of Lunar Meteor Impacts

    NASA Technical Reports Server (NTRS)

    Dunham, D. W.; Cudnik, B.; Palmer, D. M.; Sada, P. V.; Melosh, J.; Beech, M.; Pellerin, L.; Asher, D.; Frankenberger R.; Venable R.

    2000-01-01

    North American observers recorded at least six meteors striking the Moon's surface during the Leonid meteor shower on 1999 Nov. 18. Each meteor produced a flash that was recorded from at least two separate locations, marking the first confirmed lunar meteor impacts.

  6. Visual data of minor meteor showers limits of the method

    NASA Technical Reports Server (NTRS)

    Rendtel, Jurgen; Koschack, R.

    1992-01-01

    Visual meteor observations are carried out on a regular basis by many experienced observers worldwide, thus supplying information about activity of meteor showers. The limits of the method are determined by the accuracy of the detection of the meteor trail. This study shows that visual meteor observations provide reliable data for an observable hourly rate of greater than or equal to 3.

  7. Named Venusian craters

    NASA Technical Reports Server (NTRS)

    Russell, Joel F.; Schaber, Gerald G.

    1993-01-01

    Schaber et al. compiled a database of 841 craters on Venus, based on Magellan coverage of 89 percent of the planet's surface. That database, derived from coverage of approximately 98 percent of Venus' surface, has been expanded to 912 craters, ranging in diameter from 1.5 to 280 km. About 150 of the larger craters were previously identified by Pioneer Venus and Soviet Venera projects and subsequently formally named by the International Astronomical Union (IAU). Altogether, the crater names submitted to the IAU for approval to date number about 550, a little more than half of the number of craters identified on Magellan images. The IAU will consider more names as they are submitted for approval. Anyone--planetary scientist or layman--may submit names; however, candidate names must conform to IAU rules. The person to be honored must be deceased for at least three years, must not be a religious figure or a military or political figure of the 19th or 20th century, and, for Venus, must be a woman. All formally and provisionally approved names for Venusian impact craters, along with their latitude, longitude, size, and origin of their name, will be presented at LPSC and will be available as handouts.

  8. Meteor radar response function: Application to the interpretation of meteor backscatter at medium frequency

    NASA Astrophysics Data System (ADS)

    Cervera, M. A.; Holdsworth, D. A.; Reid, I. M.; Tsutsumi, M.

    2004-11-01

    Recently, Cervera and Elford (2004) extended earlier work on the development of the meteor radar response function (Elford, 1964; Thomas et al., 1988) to include a nonuniform meteor ionization profile. This approach has the advantage that the height distribution of meteors expected to be observed by a radar meteor system is able to be accurately modeled and insights into the meteoroid chemistry to be gained. The meteor radar response function is also an important tool with regard to the interpretation of meteor backscatter in other areas, e.g., modeling the expected diurnal variation of sporadic meteors, investigating the expected echo distribution over the sky, and the calculation of the expected rate curves of meteor showers. We exemplify each of these techniques from the analysis of meteor data collected by the Buckland Park 2 MHz system during October 1997. In addition, we show that the response function may be used to quantify the echo rate of a given shower relative to the sporadic background and thus determine if that shower is able to be detected by the radar.

  9. The KUT meteor radar: An educational low cost meteor observation system by radio forward scattering

    NASA Astrophysics Data System (ADS)

    Madkour, W.; Yamamoto, M.

    2016-01-01

    The Kochi University of Technology (KUT) meteor radar is an educational low cost observation system built at Kochi, Japan by successive graduate students since 2004. The system takes advantage of the continuous VHF- band beacon signal emitted from Fukui National College of Technology (FNCT) for scientific usage all over Japan by receiving the forward scattered signals. The system uses the classical forward scattering setup similar to the setup described by the international meteor organization (IMO), gradually developed from the most basic single antenna setup to the multi-site meteor path determination setup. The primary objective is to automate the observation of the meteor parameters continuously to provide amounts of data sufficient for statistical analysis. The developed software system automates the observation of the astronomical meteor parameters such as meteor direction, velocity and trajectory. Also, automated counting of meteor echoes and their durations are used to observe mesospheric ozone concentration by analyzing the duration distribution of different meteor showers. The meteor parameters observed and the methodology used for each are briefly summarized.

  10. Monte Carlo modeling and meteor showers

    NASA Technical Reports Server (NTRS)

    Kulikova, N. V.

    1987-01-01

    Prediction of short lived increases in the cosmic dust influx, the concentration in lower thermosphere of atoms and ions of meteor origin and the determination of the frequency of micrometeor impacts on spacecraft are all of scientific and practical interest and all require adequate models of meteor showers at an early stage of their existence. A Monte Carlo model of meteor matter ejection from a parent body at any point of space was worked out by other researchers. This scheme is described. According to the scheme, the formation of ten well known meteor streams was simulated and the possibility of genetic affinity of each of them with the most probable parent comet was analyzed. Some of the results are presented.

  11. SAGE III/Meteor - 3M

    NASA Technical Reports Server (NTRS)

    1999-01-01

    Full view of the SAGE III Bench Checkout Unit, Collimated Source Bench (CSB), Portable Image Generator (PIG) on tripod, and Stratospheric Aerosol Gastropheric Experiment (SAGE)/Meteor - 3M flight instrument. Photographed in building 1250, 40 foot clean room.

  12. SAGE III/Meteor - 3M

    NASA Technical Reports Server (NTRS)

    1999-01-01

    From left to right: Richard Rawls, Chip Holloway, and Art Hayhurst standing next to the Stratospheric Aerosol Gastropheric Experiment (SAGE)/Meteor - 3M flight instrument. Photographed in building 1250, 40 foot clean room.

  13. SAGE III/Meteor - 3M

    NASA Technical Reports Server (NTRS)

    1999-01-01

    Back view of the SAGE III Bench Checkout Unit, Portable Image Generator (PIG) on tripod, and the Stratospheric Aerosol Gastropheric Experiment (SAGE)/Meteor - 3M flight instrument. Photographed in building 1250, 40 foot clean room.

  14. A Meteor Shower Origin for Martian Methane

    NASA Astrophysics Data System (ADS)

    Fries, M.; Christou, A.; Archer, D.; Conrad, P.; Cooke, W.; Eigenbrode, J.; ten Kate, I. L.; Matney, M.; Niles, P.; Sykes, M.; Steele, A.; Treiman, A.

    2015-07-01

    We present and discuss the hypothesis that martian methane arises from a meteor shower source. Infall material produces methane by UV photolysis, generating localized plumes that occur after Mars/comet orbit interactions. This hypothesis is testable.

  15. Large Meteor Tracked over Northeast Alabama

    NASA Video Gallery

    On the evening of May 18, NASA all-sky meteor cameras located at NASA’s Marshall Space Flight Center and at the Walker County Science Center near Chickamauga, Ga. tracked the entry of a large meteo...

  16. Monte Carlo modeling and meteor showers

    NASA Astrophysics Data System (ADS)

    Kulikova, N. V.

    1987-08-01

    Prediction of short lived increases in the cosmic dust influx, the concentration in lower thermosphere of atoms and ions of meteor origin and the determination of the frequency of micrometeor impacts on spacecraft are all of scientific and practical interest and all require adequate models of meteor showers at an early stage of their existence. A Monte Carlo model of meteor matter ejection from a parent body at any point of space was worked out by other researchers. This scheme is described. According to the scheme, the formation of ten well known meteor streams was simulated and the possibility of genetic affinity of each of them with the most probable parent comet was analyzed. Some of the results are presented.

  17. Man-Sized Meteor Over Macon

    NASA Video Gallery

    Astronomers at NASA's Marshall Space Flight Center have recorded the brightest meteor ever seen by their network. On May 20, 2011, six-foot diameter fragment of an unknown comet entered the atmosph...

  18. Comparison with Russian analyses of meteor impact

    SciTech Connect

    Canavan, G.H.

    1997-06-01

    The inversion model for meteor impacts is used to discuss Russian analyses and compare principal results. For common input parameters, the models produce consistent estimates of impactor parameters. Directions for future research are discussed and prioritized.

  19. Meteor showers associated with 2003EH1

    NASA Astrophysics Data System (ADS)

    Babadzhanov, P. B.; Williams, I. P.; Kokhirova, G. I.

    2008-06-01

    Using the Everhart RADAU19 numerical integration method, the orbital evolution of the near-Earth asteroid 2003EH1 is investigated. This asteroid belongs to the Amor group and is moving on a comet-like orbit. The integrations are performed over one cycle of variation of the perihelion argument ω. Over such a cycle, the orbit intersect that of the Earth at eight different values of ω. The orbital parameters are different at each of these intersections and so a meteoroid stream surrounding such an orbit can produce eight different meteor showers, one at each crossing. The geocentric radiants and velocities of the eight theoretical meteor showers associated with these crossing points are determined. Using published data, observed meteor showers are identified with each of the theoretically predicted showers. The character of the orbit and the existence of observed meteor showers associated with 2003EH1 confirm the supposition that this object is an extinct comet.

  20. Craters on comets

    NASA Astrophysics Data System (ADS)

    Vincent, J.; Oklay, N.; Marchi, S.; Höfner, S.; Sierks, H.

    2014-07-01

    This paper reviews the observations of crater-like features on cometary nuclei. ''Pits'' have been observed on almost all cometary nuclei but their origin is not fully understood [1,2,3,4]. It is currently assumed that they are created mainly by the cometary activity with a pocket of volatiles erupting under a dust crust, leaving a hole behind. There are, however, other features which cannot be explained in this way and are interpreted alternatively as remnants of impact craters. This work focusses on the second type of pit features: impact craters. We present an in-depth review of what has been observed previously and conclude that two main types of crater morphologies can be observed: ''pit-halo'' and ''sharp pit''. We extend this review by a series of analysis of impact craters on cometary nuclei through different approaches [5]: (1) Probability of impact: We discuss the chances that a Jupiter Family Comet like 9P/Tempel 1 or the target of Rosetta 67P/Churyumov-Gerasimenko can experience an impact, taking into account the most recent work on the size distribution of small objects in the asteroid Main Belt [6]. (2) Crater morphology from scaling laws: We present the status of scaling laws for impact craters on cometary nuclei [7] and discuss their strengths and limitations when modeling what happens when a rocky projectile hits a very porous material. (3) Numerical experiments: We extend the work on scaling laws by a series of hydrocode impact simulations, using the iSALE shock physics code [8,9,10] for varying surface porosity and impactor velocity (see Figure). (4) Surface processes and evolution: We discuss finally the fate of the projectile and the effects of the impact-induced surface compaction on the activity of the nucleus. To summarize, we find that comets do undergo impacts although the rapid evolution of the surface erases most of the features and make craters difficult to detect. In the case of a collision between a rocky body and a highly porous

  1. Analysis of ALTAIR 1998 Meteor Radar Data

    NASA Technical Reports Server (NTRS)

    Zinn, J.; Close, S.; Colestock, P. L.; MacDonell, A.; Loveland, R.

    2011-01-01

    We describe a new analysis of a set of 32 UHF meteor radar traces recorded with the 422 MHz ALTAIR radar facility in November 1998. Emphasis is on the velocity measurements, and on inferences that can be drawn from them regarding the meteor masses and mass densities. We find that the velocity vs altitude data can be fitted as quadratic functions of the path integrals of the atmospheric densities vs distance, and deceleration rates derived from those fits all show the expected behavior of increasing with decreasing altitude. We also describe a computer model of the coupled processes of collisional heating, radiative cooling, evaporative cooling and ablation, and deceleration - for meteors composed of defined mixtures of mineral constituents. For each of the cases in the data set we ran the model starting with the measured initial velocity and trajectory inclination, and with various trial values of the quantity mPs 2 (the initial mass times the mass density squared), and then compared the computed deceleration vs altitude curves vs the measured ones. In this way we arrived at the best-fit values of the mPs 2 for each of the measured meteor traces. Then further, assuming various trial values of the density Ps, we compared the computed mass vs altitude curves with similar curves for the same set of meteors determined previously from the measured radar cross sections and an electrostatic scattering model. In this way we arrived at estimates of the best-fit mass densities Ps for each of the cases. Keywords meteor ALTAIR radar analysis 1 Introduction This paper describes a new analysis of a set of 422 MHz meteor scatter radar data recorded with the ALTAIR High-Power-Large-Aperture radar facility at Kwajalein Atoll on 18 November 1998. The exceptional accuracy/precision of the ALTAIR tracking data allow us to determine quite accurate meteor trajectories, velocities and deceleration rates. The measurements and velocity/deceleration data analysis are described in Sections

  2. Tritium concentrations in the active Pu'u O'o crater, Kilauea volcano, Hawaii: implications for cold fusion in the Earth's interior

    USGS Publications Warehouse

    Quick, J.E.; Hinkley, T.K.; Reimer, G.M.; Hedge, C.E.

    1991-01-01

    The assertion that deuterium-deuterium fusion may occur at low temperature suggests a potential new source of geothermal heat. If a cold-fusion-like process occurs within the Earth, then a test for its existence would be a search for anomalous tritium in volcanic emissions. The Pu'u O'o crater is the first point at which large amounts of water are degassed from the magma that feeds the Kilauea system. The magma is probably not contaminated by meteoric-source ground water prior to degassing at Pu'u O'o, although mixing of meteoric and magmatic H2O occurs within the crater. Tritium contents of samples from within the crater are lower than in samples taken simultaneously from the nearby upwind crater rim. These results provide no evidence in support of a cold-fusion-like process in the Earth's interior. ?? 1991.

  3. Error control coding for meteor burst channels

    NASA Astrophysics Data System (ADS)

    Frederick, T. J.; Belkerdid, M. A.; Georgiopoulos, M.

    The performance of several error control coding schemes for a meteor burst channel is studied via analysis and simulation. These coding strategies are compared using the probability of successful transmission of a fixed size packet through a single burst as a performance measure. The coding methods are compared via simulation for several realizations of meteor burst. It is found that, based on complexity and probability of success, fixed-rate convolutional codes with soft decision Viterbi decoding provide better performance.

  4. Impact Cratering Calculations

    NASA Technical Reports Server (NTRS)

    Ahrens, Thomas J.

    2002-01-01

    Many Martian craters are surrounded by ejecta blankets which appear to have been fluidized forming lobate and layered deposits terminated by one or more continuous distal scarps, or ramparts. One of the first hypotheses for the formation of so-called rampart ejecta features was shock-melting of subsurface ice, entrainment of liquid water into the ejecta blanket, and subsequent fluidized flow. Our work quantifies this concept. Rampart ejecta found on all but the youngest volcanic and polar regions, and the different rampart ejecta morphologies are correlated with crater size and terrain. In addition, the minimum diameter of craters with rampart features decreases with increasing latitude indicating that ice laden crust resides closer to the surface as one goes poleward on Mars. Our second goal in was to determine what strength model(s) reproduce the faults and complex features found in large scale gravity driven craters. Collapse features found in large scale craters require that the rock strength weaken as a result of the shock processing of rock and the later cratering shear flows. In addition to the presence of molten silicate in the intensely shocked region, the presence of water, either ambient, or the result of shock melting of ice weakens rock. There are several other mechanisms for the reduction of strength in geologic materials including dynamic tensile and shear induced fracturing. Fracturing is a mechanism for large reductions in strength. We found that by incorporating damage into the models that we could in a single integrated impact calculation, starting in the atmosphere produce final crater profiles having the major features found in the field measurements (central uplifts, inner ring, terracing and faulting). This was accomplished with undamaged surface strengths (0.1 GPa) and in depth strengths (1.0 GPa).

  5. Crater Lake revealed

    USGS Publications Warehouse

    Ramsey, David W.; Dartnell, Peter; Bacon, Charles R.; Robinson, Joel E.; Gardner, James V.

    2003-01-01

    Around 500,000 people each year visit Crater Lake National Park in the Cascade Range of southern Oregon. Volcanic peaks, evergreen forests, and Crater Lake’s incredibly blue water are the park’s main attractions. Crater Lake partially fills the caldera that formed approximately 7,700 years ago by the eruption and subsequent collapse of a 12,000-foot volcano called Mount Mazama. The caldera-forming or climactic eruption of Mount Mazama drastically changed the landscape all around the volcano and spread a blanket of volcanic ash at least as far away as southern Canada. Prior to the climactic event, Mount Mazama had a 400,000 year history of cone building activity like that of other Cascade volcanoes such as Mount Shasta. Since the climactic eruption, there have been several less violent, smaller postcaldera eruptions within the caldera itself. However, relatively little was known about the specifics of these eruptions because their products were obscured beneath Crater Lake’s surface. As the Crater Lake region is still potentially volcanically active, understanding past eruptive events is important to understanding future eruptions, which could threaten facilities and people at Crater Lake National Park and the major transportation corridor east of the Cascades. Recently, the lake bottom was mapped with a high-resolution multibeam echo sounder. The new bathymetric survey provides a 2m/pixel view of the lake floor from its deepest basins virtually to the shoreline. Using Geographic Information Systems (GIS) applications, the bathymetry data can be visualized and analyzed to shed light on the geology, geomorphology, and geologic history of Crater Lake.

  6. Meteoric Ions in Planetary Ionospheres

    NASA Technical Reports Server (NTRS)

    Pesnell, W. D.; Grebowsky, Joseph M.; Vondrak, Richard R. (Technical Monitor)

    2001-01-01

    Solar system debris, in the form of meteoroids, impacts every planet. The flux, relative composition and speed of the debris at each planet depends on the planet's size and location in the solar system. Ablation in the atmosphere evaporates the meteoric material and leaves behind metal atoms. During the ablation process metallic ions are formed by impact ionization. For small inner solar system planets, including Earth, this source of ionization is typically small compared to either photoionization or charge exchange with ambient molecular ions. For Earth, the atmosphere above the main deposition region absorbs the spectral lines capable of ionizing the major metallic atoms (Fe and Mg) so that charge exchange with ambient ions is the dominant source. Within the carbon dioxide atmosphere of Mars (and possibly Venus), photoionization is important in determining the ion density. For a heavy planet like Jupiter, far from the sun, impact ionization of ablated neutral atoms by impacts with molecules becomes a prominent source of ionization due to the gravitational acceleration to high incident speeds. We will describe the processes and location and extent of metal ion layers for Mars, Earth and Jupiter, concentrating on flagging the uncertainties in the models at the present time. This is an important problem, because low altitude ionosphere layers for the planets, particularly at night, probably consist predominantly of metallic ions. Comparisons with Earth will be used to illustrate the differing processes in the three planetary atmospheres.

  7. January and February Meteor Showers Detected by CAMS: the Cameras for Allsky Meteor Surveillance

    NASA Astrophysics Data System (ADS)

    Johnson, Beth; Jenniskens, P. M.

    2014-01-01

    Many meteor showers are in need of validation. Of 493 meteor showers listed in the IAU Working List of Mete-or Showers, only 95 are established. Of the rest, it is uncertain whether they exist or not. The goal of the Cameras for Allsky Meteor Surveillance (CAMS) project in California is to validate or remove the remaining 325 showers. CAMS scales up the use of low-light-level video for meteor triangulation, by deploying 60 video cameras spread over three sites. Once the video data has been analyzed, showers can be confirmed by comparing arrival time, direc-tion of the radiant, and speed of the individual meteors. Once established, showers can be linked to their parent bod-ies and meteoroid streams. The CAMS stations are located in Sunnyvale, at Fremont Peak Observatory, and at Lick Observatory, to the south and east of Sunnyvale, respectively. Each station contains 20 low-light-level security cameras arrayed to view the entire sky above 30°. During the night, the video data from the cameras is written to disk and analysed in day-time with the MeteorScan software package to find moving objects. Eight-second video sequences are saved for all detections. The video sequences are combined at the SETI Institute, where astrometric calibration files are generated and meteors detected from at least two stations simultaneously are found interactively using the Coincidence program. Coincidence also calculates the radiant and velocity of each meteor. Here, we discuss results obtained in January and February 2013. Over 7,500 meteor orbits were cataloged in this period. This outcome doubled the detection rate from the previous two years of CAMS data.We will present graphs of the detected meteor showers and discuss their parent body sources.

  8. ARIZONA INDIAN RESERVATIONS

    EPA Science Inventory

    Polygon coverage of all Indian Reservations in Arizona. Reservation boundaries are compiled from multiple sources and are derived from several different source scales. Information such as reservation type, primary tribe name and location source are included with the coverage. A...

  9. Replacing Arizona's Roofs.

    ERIC Educational Resources Information Center

    Fickes, Michael

    2000-01-01

    Discusses the Arizona statewide mandate to spend $500 million to repair or replace roofs in its public school system. Data from the state's evaluation process are provided, including how the state will fund the project. (GR)

  10. Clayheads in Arizona.

    ERIC Educational Resources Information Center

    Schubert, Thorne Erwin

    1990-01-01

    Describes how junior high school students in Arizona combine what they have learned in ceramic history class with ceramic production skills to create their own personal ceramic heads in their images. (KM)

  11. Diatremes and craters attributed to natural explosions

    USGS Publications Warehouse

    Shoemaker, Eugene Merle

    1956-01-01

    Diatremes - volcanic pipes attributed to explosion - and craters have been studied to infer the ultimate causes and physical conditions attending natural explosive processes. Initial piercement of diatremes on the Navajo reservation, Arizona was probably along a fracture propagated by a high-pressure aqueous fluid. Gas rising at high velocity along the fracture would become converted to a gas-solid fluidized system by entrainment of wall- rock fragments. The first stages of widening of the vent are probably accomplished mainly by simple abrasion of the high-velocity fluidized system on the walls of the fracture. As the vent widens, its enlargement may be accelerated by inward spalling of the walls. The inferred mechanics of the Navajo-Hopi diatremes is used to illustrate the possibility of diatreme formation over a molten salt mass.

  12. Venus - Impact Crater 'Isabella

    NASA Technical Reports Server (NTRS)

    1992-01-01

    Crater Isabella, with a diameter of 175 kilometers (108 miles), seen in this Magellan radar image, is the second largest impact crater on Venus. The feature is named in honor of the 15th Century queen of Spain, Isabella of Castile. Located at 30 degrees south latitude, 204 degrees east longitude, the crater has two extensive flow-like structures extending to the south and to the southeast. The end of the southern flow partially surrounds a pre-existing 40 kilometer (25 mile) circular volcanic shield. The southeastern flow shows a complex pattern of channels and flow lobes, and is overlain at its southeastern tip by deposits from a later 20 kilometer (12 mile) diameter impact crater, Cohn (for Carola Cohn, Australian artist, 1892-1964). The extensive flows, unique to Venusian impact craters, are a continuing subject of study for a number of planetary scientists. It is thought that the flows may consist of 'impact melt,' rock melted by the intense heat released in the impact explosion. An alternate hypothesis invokes 'debris flows,' which may consist of clouds of hot gases and both melted and solid rock fragments that race across the landscape during the impact event. That type of emplacement process is similar to that which occurs in violent eruptions on Earth, such as the 1991 Mount Pinatubo eruption in the Philippines.

  13. Geophysical Signature of the Lake Bosumtwi Impact Crater, Ghana

    NASA Astrophysics Data System (ADS)

    Karp, T.; Milkereit, B.; Janle, P.; Danuor, S. K.; Berckhemer, H.; Pohl, J.; Scholz, C. A.

    2001-12-01

    The Bosumtwi impact structure in Ghana has an age of 1.07 Ma, a rim-to-rim diameter of 10.5 km, and is the youngest large impact crater on earth. It is the source crater of the Ivory Coast tectites (Koeberl et al., Geoch. Cosmoch. Acta 61, 1997). The central part of the structure is filled by Lake Bosumtwi. Marine seismic studies were conducted to investigate crater morphology (thickness of post-impact sediments, depth and shape of central uplift). Refraction seismic (OBH and PDAS seismometer) and multichannel reflection data were collected to image the complex subsurface crater structure. Results from integrated modelling reveal low P-wave velocities in the young post-impact sediments (less than 1.8 km/s) and a prominent central uplift structure about 120 m high. The total thickness of the sediments does not exceed 350 m. Gravity and magnetic surveys complement regional airborne geophysical data across the structure (Plado et al., Meteor. & Planet. Sc., 35, 2000). Gravity data from 160 stations on land around the lake show the expected minimum resulting from the sedimentary filling of the lake, low density impact formations, brecciated and fragmented basement. In the fall of 2001 additional gravity measurements will be carried out on the lake to better delineate prominent anomalies associated with the central structure. The magnetic anomalies are attributed to remanent magnetization of melt, breccias and footwall complex. Further integration of different data sets will help to develop a detailed lithological model of the crater's subsurface structure. The geophysical data confirm that the Lake Bosumtwi structure provides an ideal setting for drilling of a young and large impact crater.

  14. Results of Lunar Impact Observations During Geminid Meteor Shower Events

    NASA Technical Reports Server (NTRS)

    Suggs, R. J.; Suggs, R. M.

    2015-01-01

    Meteoroids are natural particles with origins from comets, asteroids, and planets from within the solar system. On average, 33 metric tons (73,000 lb) of meteoroids hit Earth everyday with velocities ranging between 20 and 72 km/s. However, the vast majority of these meteoroids disintegrate in the atmosphere and never make it to the ground. The Moon also encounters the same meteoroid flux, but has no atmosphere to stop them from striking the surface. At such speeds even a small meteoroid has incredible energy. A meteoroid with a mass of only 5 kg can excavate a crater over 9 m across, hurling 75 metric tons (165,000 lb) of lunar soil and rock on ballistic trajectories above the lunar surface. Meteoroids with particle sizes as small as 100 micrometer (1 Microgram) can do considerable damage to spacecraft in Earth's orbit and beyond. Impacts can damage thermal protection systems, radiators, windows, and pressurized containers. Secondary effects might include partial penetration or pitting, local deformation, and surface degradation that can cause a failure upon reentry. The speed, mass, density, and flux of meteoroids are important factors for design considerations and mitigation during operations. Lunar operations (unmanned and manned) are also adversely affected by the meteoroid flux. Ejecta from meteoroid impacts is also part of the lunar environment and must be characterized. Understanding meteoroid fluxes and the associated risk of meteoroids impacting spacecraft traveling in and beyond Earth's orbit is the objective of the Meteoroid Environment Office (MEO) located at Marshall Space Flight Center (MSFC). One of the MEO's programs is meteoroid impact monitoring of the Moon. The large collecting area of the night side of the lunar disk provides statistically significant counts of meteoroids that can provide useful information about the flux of meteoroids in the hundreds of grams to kilograms size range. This information is not only important for characterizing

  15. The scaling of secondary craters

    NASA Technical Reports Server (NTRS)

    Croft, Steven K.

    1991-01-01

    Secondary craters are common features around fresh planetary-scale primary impact craters throughout most of the Solar System. They derive from the ejection phase of crater formation, thus secondary scaling relations provide constraints on parameters affecting ejection processes. Secondary crater fields typically begin at the edge of the continuous ejecta blankets (CEB) and extend out several crater radii. Secondaries tend to have rounded rims and bilateral symmetry about an axis through the primary crater's center. Prominent secondary chains can extend inward across the CEB close to the rim. A simple method for comparing secondary crater fields was employed: averaging the diameters and ranges from the center of the primary crater of the five largest craters in a secondary crater field. While not as much information is obtained about individual crater fields by this method as in more complete secondary field mapping, it facilitates rapid comparison of many secondary fields. Also, by quantifying a few specific aspects of the secondary crater field, this method can be used to construct scaling relations for secondary craters.

  16. Dune Field in a Southern Highlands Crater

    NASA Technical Reports Server (NTRS)

    2003-01-01

    [figure removed for brevity, see original site]

    Released 5 September 2003

    Dark dunes sit on a rough, eroding sedimentary surface in the floor of an 83 km diameter crater. This crater is one of dozens in Noachis Terra, in the southern highlands of Mars, to have both dark dunes and an eroding surface. Note how the dunes seem to ignore the underlying rough surface in some cases, while in other places the dunes seem to have wrapped themselves around sharp knobs.

    Image information: VIS instrument. Latitude -40.5, Longitude 34.6 East (325.4 West). 19 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  17. Small Impact Crater

    NASA Technical Reports Server (NTRS)

    2005-01-01

    22 June 2005 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a small impact crater with a 'butterfly' ejecta pattern. The butterfly pattern results from an oblique impact. Not all oblique impacts result in an elliptical crater, but they can result in a non-radial pattern of ejecta distribution. The two-toned nature of the ejecta -- with dark material near the crater and brighter material further away -- might indicate the nature of subsurface materials. Below the surface, there may be a layer of lighter-toned material, underlain by a layer of darker material. The impact throws these materials out in a pattern that reflects the nature of the underlying layers.

    Location near: 3.7oN, 348.2oW Image width: 3 km (1.9 mi) Illumination from: lower left Season: Northern Autumn

  18. 'Happy Face' Crater

    NASA Technical Reports Server (NTRS)

    2003-01-01

    MGS MOC Release No. MOC2-361, 15 May 2003

    Every day, the Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) wide angle instruments obtain a global view of the planet to help monitor weather and seasonal patterns of frost deposition and removal. The two pictures shown here are taken from the same daily global image mosaic (the only difference is that each was processed slightly differently). The pictures show Galle Crater, informally known as 'Happy Face,' as it appeared in early southern winter. The white-ish gray surfaces are coated with wintertime carbon dioxide frost. The pattern of frost distribution gives the appearance that 'Happy Face' has opened its mouth. Galle Crater is located on the east rim of Argyre at 51oS, 31oW. Sunlight illuminates the scene from the upper left. Galle Crater is 230 km (143 mi) across.

  19. Impact crater scaling laws

    NASA Technical Reports Server (NTRS)

    Holsapple, K. A.

    1987-01-01

    Impact craters are numerous on planetary bodies and furnish important information about the composition and past histories of those bodies. The interpretation of that information requires knowledge about the fundamental aspects of impact cratering mechanics. Since the typical conditions of impacts are at a size scale and velocity far in excess of experimental capabilities, direct simulations are precluded. Therefore, one must rely on extrapolation from experiments of relatively slow impacts of very small bodies, using physically based scaling laws, or must study the actual cases of interest using numerical code solutions of the fundamental physical laws that govern these processes. A progress report is presented on research on impact cratering scaling laws, on numerical studies that were designed to investigate those laws, and on various applications of the scaling laws developed by the author and his colleagues. These applications are briefly reviewed.

  20. 'Bonneville Crater' Panorama

    NASA Technical Reports Server (NTRS)

    2004-01-01

    [figure removed for brevity, see original site] Click on the image for 'Bonneville Crater' Panorama (QTVR)

    This 360-degree view from a position beside the crater informally named 'Bonneville' was assembled from frames taken by the panoramic camera on NASA's Mars Exploration Rover Spirit. Half of this panorama was first released on March 15, 2004. The entire mosaic, recently completed, reveals not only the crater rim and interior, but Spirit's tracks and a glimpse at part of the rover. The images were acquired on sol 68, March 12, 2004, just one day after Spirit reached this location.

    The image is a false-color composite made from frames taken with the camera's L2 (750 nanometer), L5 (530 nanometer) and L6 (480 nanometer) filters.

  1. Meteor Beliefs Project: an introduction to the meteor-dragon special

    NASA Astrophysics Data System (ADS)

    McBeath, A.

    2003-12-01

    By way of introduction to three Meteor Beliefs Project articles on the connection between dragons and meteors in East European folk-belief in this issue of WGN, some notes are given on the possible origins of this largely western Euroasian belief, together with some short comments leading in to the three articles.

  2. Mesospheric temperature estimation from meteor decay times during Geminids meteor shower

    NASA Astrophysics Data System (ADS)

    Kozlovsky, Alexander; Lukianova, Renata; Shalimov, Sergey; Lester, Mark

    2016-02-01

    Meteor radar observations at the Sodankylä Geophysical Observatory (67° 22'N, 26° 38'E, Finland) indicate that the mesospheric temperature derived from meteor decay times is systematically underestimated by 20-50 K during the Geminids meteor shower which has peak on 13 December. A very good coincidence of the minimum of routinely calculated temperature and maximum of meteor flux (the number of meteors detected per day) was observed regularly on that day in December 2008-2014. These observations are for a specific height-lifetime distribution of the Geminids meteor trails and indicate a larger percentage of overdense trails compared to that for sporadic meteors. A consequence of this is that the routine estimates of mesospheric temperature during the Geminids are in fact underestimates. The observations do, however, indicate unusual properties (e.g., mass, speed, or chemical composition) of the Geminids meteoroids. Similar properties were found also for Quadrantids in January 2009-2015, which like the Geminids has as a parent body an asteroid, but not for other meteor showers.

  3. Craters! A Multi-Science Approach to Cratering and Impacts.

    ERIC Educational Resources Information Center

    Hartmann, William K.; Cain, Joe

    This book provides a complete Scope Sequence and Coordination teaching module. First, craters are introduced as a generally observable phenomena. Then, by making craters and by investigating the results, students gain close-up, hands-on experience with impact events and their products. Real crater examples from the Moon and elsewhere are included…

  4. Khensu Crater on Ganymede

    NASA Technical Reports Server (NTRS)

    1997-01-01

    The dark-floored crater, Khensu, is the target of this image of Ganymede. The solid state imaging camera on NASA's Galileo spacecraft imaged this region as it passed Ganymede during its second orbit through the Jovian system. Khensu is located at 2 degrees latitude and 153 degrees longitude in a region of bright terrain known as Uruk Sulcus, and is about 13 kilometers (8 miles) in diameter. Like some other craters on Ganymede, it possesses an unusually dark floor and a bright ejecta blanket. The dark component may be residual material from the impactor that formed the crater. Another possibility is that the impactor may have punched through the bright surface to reveal a dark layer beneath.

    Another large crater named El is partly visible in the top-right corner of the image. This crater is 54 kilometers (34 miles) in diameter and has a small 'pit' in its center. Craters with such a 'central pit' are common across Ganymede and are especially intriguing since they may reveal secrets about the structure of the satellite's shallow subsurface.

    North is to the top-left of the picture and the sun illuminates the surface from nearly overhead. The image covers an area about 100 kilometers (62 miles) by 86 kilometers (54 miles) across at a resolution of 111 meters (370 feet) per picture element. The image was taken on September 6, 1996 by the solid state imaging (CCD) system on NASA's Galileo spacecraft.

    The Jet Propulsion Laboratory, Pasadena, CA manages the Galileo mission for NASA's Office of Space Science, Washington, DC. JPL is an operating division of California Institute of Technology (Caltech).

    This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://galileo.jpl.nasa.gov.

  5. Nergal Crater on Ganymede

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Two impact craters surrounded by an unusual ejecta blanket dominate this high resolution image of the surface of Jupiter's moon, Ganymede. NASA's Galileo spacecraft imaged this region as it passed Ganymede during its second orbit through the Jovian system. North is to the top of the picture and the sun illuminates the surface from the southeast. Nergal, the larger crater, is about eight kilometers (five miles) in diameter, while the smaller (unnamed) crater to its west is three kilometers (1.8 miles) across. The craters are situated in a region of bright grooved terrain named Byblus Sulcus, located in the northern part of Marius Regio at 39 degrees latitude and 201 degrees longitude. The distinctive ejecta blanket that surrounds them is darker nearer the craters and brighter further away. The inner region of the ejecta is characterized by a lobate appearance indicative of the flow of a liquid (or slushy) substance over the surface. The flow was probably icy surface material melted by the energy released during the impact that formed the crater.

    The picture covers an area about 48 kilometers (30 miles) by 34 kilometers (21 miles) across at a resolution of 86 meters (287 feet) per picture element. The image was taken on September 6, 1996 by the solid state imaging (CCD) system on NASA's Galileo spacecraft.

    The Jet Propulsion Laboratory, Pasadena, CA manages the Galileo mission for NASA's Office of Space Science, Washington, DC. JPL is an operating division of California Institute of Technology (Caltech).

    This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://galileo.jpl.nasa.gov.

  6. The Southern Argentine Agile Meteor Radar (SAAMER)

    NASA Astrophysics Data System (ADS)

    Janches, Diego

    2014-11-01

    The Southern Argentina Agile Meteor Radar (SAAMER) is a new generation system deployed in Rio Grande, Tierra del Fuego, Argentina (53 S) in May 2008. SAAMER transmits 10 times more power than regular meteor radars, and uses a newly developed transmitting array, which focuses power upward instead of the traditional single-antenna-all-sky configuration. The system is configured such that the transmitter array can also be utilized as a receiver. The new design greatly increases the sensitivity of the radar enabling the detection of large number of particles at low zenith angles. The more concentrated transmitted power enables additional meteor studies besides those typical of these systems based on the detection of specular reflections, such as routine detections of head echoes and non-specular trails, previously only possible with High Power and Large Aperture radars. In August 2010, SAAMER was upgraded to a system capable to determine meteoroid orbital parameters. This was achieved by adding two remote receiving stations approximately 10 km away from the main site in near perpendicular directions. The upgrade significantly expands the science that is achieved with this new radar enabling us to study the orbital properties of the interplanetary dust environment. Because of the unique geographical location, SAAMER allows for additional inter-hemispheric comparison with measurements from Canadian Meteor Orbit Radar, which is geographically conjugate. Initial surveys show, for example, that SAAMER observes a very strong contribution of the South Toroidal Sporadic meteor source, of which limited observational data is available. In addition, SAAMER offers similar unique capabilities for meteor showers and streams studies given the range of ecliptic latitudes that the system enables detailed study of showers at high southern latitudes (e.g July Phoenicids or Puppids complex). Finally, SAAMER is ideal for the deployment of complementary instrumentation in both, permanent

  7. Planetary cratering mechanics

    NASA Technical Reports Server (NTRS)

    Okeefe, John D.; Ahrens, Thomas J.

    1992-01-01

    To obtain a quantitative understanding of the cratering process over a broad range of conditions, we have numerically computed the evolution of impact induced flow fields and calculated the time histories of the major measures of crater geometry (e.g., depth diameter, lip height ...) for variations in planetary gravity (0 to 10 exp 9 cm/sq seconds), material strength (0 to 140 kbar), thermodynamic properties, and impactor radius (0.05 to 5000 km). These results were fit into the framework of the scaling relations of Holsapple and Schmidt (1987). We describe the impact process in terms of four regimes: (1) penetration; (2) inertial; (3) terminal; and (4) relaxation.

  8. Crater and Wind Streak

    NASA Technical Reports Server (NTRS)

    2003-01-01

    MGS MOC Release No. MOC2-461, 23 August 2003

    This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a crater with a bright wind streak in southern Acidalia Planitia. The streak is mostly likely a very thin coating of dust. The orientation of the streak indicates that the winds responsible for its formation and maintenance came from the northeast (upper right) and blew toward the lower left (southwest). The crater is located near 24.8oN, 39.1oW. The image covers an area 3 km (1.9 mi) wide. Sunlight illuminates the scene from the lower left.

  9. Layered Crater Walls

    NASA Technical Reports Server (NTRS)

    2006-01-01

    16 September 2006 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows an impact crater that is approximately 3.5 kilometers (2.2 miles) in diameter. It is located to the northeast of Olympus Mons, in the Tharsis Region. Layered rock units are visible on the inside of the raised crater rim.

    Location near: 70.7oN, 271.0oW Image width: 3 km (1.9 mi) Illumination from: lower left Season: Northern Spring

  10. An understudied crater in Nevada

    NASA Astrophysics Data System (ADS)

    Jamieson, Harry D.

    1992-09-01

    A little-known possible meteorite crater discovered in the early 1920's in Nye County, Nevada, by Ralph Irwing is described. The crater called the Irwing Crater was visited by the author on July 11, 1992. Photographs of the feature are presented.

  11. Lunar Regolith Maturity Controlled By Ilmenite Content And Micro-Meteor Flux Variability

    NASA Astrophysics Data System (ADS)

    Schmitt, H. H.

    2013-12-01

    Synthesis of Is/FeO maturity indexes for Apollo 17 regolith samples in the valley of Taurus-Littrow on the Moon indicate that high levels of ilmenite in the samples significantly reduces the level of this indicator of space exposure. The analysis, along with consideration of regolith glass characteristics, also discloses that micro-meteor fluxes vary over geologic time, presumably in response to significant impact events in the Asteroid Belt. Surface samples of ilmenite-poor, silicate-rich regolith have about 80-90% higher maturity indexes than surface samples of ilmenite-rich, basaltic regolith of comparable exposure. For comparison of the history of various regolith exposures to the space environment, Taurus-Littrow's light mantle avalanche deposit, the youngest large area stratigraphic unit, provides a specific time horizon. For at least the last ~110 million years, the currently estimated age of the light mantle avalanche, most near surface (upper 1-5cm) regolith has had approximately the same exposure to micro-meteors. The surface of the largely ilmenite-rich basalt fill in the valley has been exposed to space at least as long or possibly 30 million years longer than the light mantle, based on exposure ages for large boulder ejecta in the Camelot cluster of craters. High apparent maturity (Is/FeO >80), however, exists only on three types of regolith surfaces: (1) the North Massif apron (e.g., 77431), (2) the light mantle avalanche deposit (e.g., 72161), and (3) low ilmenite basalt (e.g., 72150). Only intermediate to low maturity (Is/FeO <60) has developed in surface regolith overlying high titanium basalt (e.g., 70181). TiO2/TiO2+FeO ratios provide a good measure of original ilmenite content, ilmenite being the only quantitatively significant titanium-bearing mineral in the regolith. Those ratios for samples showing high and intermediate apparent maturity are about 0.35 and 0.25, respectively. A well documented, 3.5 billion year old basaltic regolith (77240

  12. Protecting Venus from Asteroids, Comets, and Meteors

    NASA Technical Reports Server (NTRS)

    McKinnon, William B.; Zahnle, K. J.; Cuzzi, Jeffrey (Technical Monitor)

    1996-01-01

    It is well accepted that the dense, thick atmosphere of Venus prevents most small cosmic bodies from reaching the surface and forming craters. We have examined this atmospheric intervention in detail, incorporating the lessons learned from the extensive modeling of impactor deceleration and flattening motivated by the SL-9 impacts with Jupiter. We employ a "pancake" model, which best matches detailed code simulations of atmospheric energy deposition, and Schmidt-Holsapple crater scaling modified for complex (flattened) craters. We adopt the distributions of Venus-crossing asteroids and comets determined by E.M. Shoemaker and co-workers, as well as generalizations of these distributions. Our nominal simulation of the venusian crater record is shown below, calibrated to the total number of venusian craters (940). As nearly all craters on Venus are well-preserved and relatively uniformly distributed, such simulations constrain the age of the surface. The fit is reasonable, with a nominal crater retention age of approx. 700 Ma. The fit at the large-crater end is improved if the number of large asteroids is increased, which Shoemaker argues is in fact more representative of the long-term (over several 100 Ma) average, and if Halley-family comets are included. The ages we obtain under a variety of modeling choices that produce good fits (including using Shoemaker's preferred crater scaling) are approx. 700-900 Ma, substantially greater than the most widely cited age estimate in the literature (-300 Ma). The key difference is that we find very large depletions in the production of 20-30-km craters (see figure) compared with previous estimates, the size range at which atmospheric effects are often calibrated or assumed nearly negligible. As venusian global resurfacing recedes deeper into history, the likelihood that Venus is resting between bouts of activity diminishes. Venus, like Mars, may instead be dying or dead.

  13. Asteroid 1620 Geographos: II. Associated Meteor Streams

    NASA Astrophysics Data System (ADS)

    Ryabova, G. O.

    2002-05-01

    This study attempts to answer the following questions. Are there meteor streams genetically related to asteroid 1620 Geographos? When and how were they generated? Can we find any of them in the catalogs of orbits of meteors that have been observed? Numerous model streams, varying in particle-ejection scheme and in the moment of generation, have been considered. It has been found that the meteor streams observed from the Earth were most likely produced as a result of a collision with a small body. However, the generation of the meteor stream under the combined effect of rotation and tidal forces during the asteroid's close approach to the Earth cannot also be ruled out. Meteoroid streams formed at high ejection velocities (up to 1 km/s) can approach the Earth's orbit twice per orbital period: once before perihelion (in February-March) and once after perihelion (in August). The 44 orbits close to the model ones were found in the catalogs of meteoroid orbits. A taxonomic structure has been built for them. The distribution of ejection velocities for the models of Earth-approaching meteoroids points to the impact of an overtaking body, but the moment of collision remains unknown. Thus, it is quite possible that asteroid Geographos is the parent body for twin meteor showers observed at the Earth: Spring and Autumn Geographids.

  14. BRAMS: The Belgian RAdio Meteor Stations

    NASA Technical Reports Server (NTRS)

    Lamy, H.; Ranvier, S.; De Keyser, J.; Calders, S.; Gamby, E.; Verbeeck, C.

    2011-01-01

    In the last months, the Belgian Institute for Space Aeronomy has been developing a Belgian network for observing radio meteors using forward scattering technique. This network is called BRAMS for Belgian RAdio Meteor Stations. Two beacons emitting a circularly polarized pure sine wave toward the zenith act as the transmitters at frequencies of 49.97 and 49.99 MHz. The first one located in Dourbes (Southern Belgium) emits a constant power of 150 Watts while the one located in Ieper (Western Belgium) emits a constant power of 50 Watts. The receiving network consists of about 20 stations hosted mainly by radio amateurs. Two stations have crossed-Yagi antennas measuring horizontal and vertical polarizations of the waves reflected off meteor trails. This will enable a detailed analysis of the meteor power profiles from which physical parameters of the meteoroids can be obtained. An interferometer consisting of 5 Yagi-antennas will be installed at the site of Humain in order to determine the angular detection of one reflection point, allowing us to determine meteoroid trajectories. We describe this new meteor observing facility and present the goals we expect to achieve with the network.

  15. CAMS confirmation of previously reported meteor showers

    NASA Astrophysics Data System (ADS)

    Jenniskens, P.; Nénon, Q.; Gural, P. S.; Albers, J.; Haberman, B.; Johnson, B.; Holman, D.; Morales, R.; Grigsby, B. J.; Samuels, D.; Johannink, C.

    2016-03-01

    Leading up to the 2015 IAU General Assembly, the International Astronomical Union's Working List of Meteor Showers included 486 unconfirmed showers, showers that are not certain to exist. If confirmed, each shower would provide a record of past comet or asteroid activity. Now, we report that 41 of these are detected in the Cameras for Allsky Meteor Surveillance (CAMS) video-based meteor shower survey. They manifest as meteoroids arriving at Earth from a similar direction and orbit, after removing the daily radiant drift due to Earth's motion around the Sun. These showers do exist and, therefore, can be moved to the IAU List of Established Meteor Showers. This adds to 31 previously confirmed showers from CAMS data. For each shower, finding charts are presented based on 230,000 meteors observed up to March of 2015, calculated by re-projecting the drift-corrected Sun-centered ecliptic coordinates into more familiar equatorial coordinates. Showers that are not detected, but should have, and duplicate showers that project to the same Sun-centered ecliptic coordinates, are recommended for removal from the Working List.

  16. Rim of Henry Crater

    NASA Technical Reports Server (NTRS)

    2002-01-01

    (Released 02 April 2002) This portion of the rim of Henry Crater has numerous dark streaks located on the slopes of the inner crater wall. These dark slope streaks have been suggested to have formed when the relatively bright dust that mantles the slopes slides downhill, either exposing a dust-free darker surface or creating a darker surface by increasing its roughness. The topography in this region appears muted, indicating the presence of regional dust mantling. The materials on floor of the crater (middle to lower left) are layered, with differing degrees of hardness and resistance to erosion producing cliffs (resistant layers) and ledges (easily eroded layers). These layered materials may have been originally deposited in water, although deposition by other means, such as windblown dust and sand, is also possible. Henry Crater, named after a 19th Century French astronomer, is 170 km in diameter and is located at 10.9o N, 336.7o W (23.3o E) in a region called Arabia Terra.

  17. Reading 'Endurance Crater'

    NASA Technical Reports Server (NTRS)

    2004-01-01

    [figure removed for brevity, see original site] Figure 1

    This image shows the area inside 'Endurance Crater' that the Mars Exploration Rover Opportunity has been examining. The rover is investigating the distinct layers of rock that make up this region. Each layer is defined by subtle color and texture variations and represents a separate chapter in Mars' history. The deeper the layer, the further back in time the rocks were formed. Scientists are 'reading' this history book by systematically studying each layer with the rover's scientific instruments. So far, data from the rover indicate that the top layers are sulfate-rich, like the rocks observed in 'Eagle Crater.' This implies that water processes were involved in forming the materials that make up these rocks.

    In figure 1, the layer labeled 'A' in this picture contains broken-up rocks that most closely resemble those of 'Eagle Crater.' Layers 'B,C and D' appear less broken up and more finely laminated. Layer 'E,' on the other hand, looks more like 'A.' At present, the rover is examining layer 'D.'

    So far, data from the rover indicates that the first four layers consist of sulfate-rich, jarosite-containing rocks like those observed in Eagle Crater. This implies that water processes were involved in forming the materials that make up these rocks, though the materials themselves may have been laid down by wind.

    This image was taken by Opportunity's navigation camera on sol 134 (June 9, 2004).

  18. Impact Cratering Calculations

    NASA Technical Reports Server (NTRS)

    Ahrens, Thomas J.

    1997-01-01

    Understanding the physical processes of impact cratering on planetary surfaces and atmospheres as well as collisions of finite-size self-gravitating objects is vitally important to planetary science. The observation has often been made that craters are the most ubiquitous landform on the solid planets and the satellites. The density of craters is used to date surfaces on planets and satellites. For large ringed basin craters (e.g. Chicxulub), the issue of identification of exactly what 'diameter' transient crater is associated with this structure is exemplified by the arguments of Sharpton et al. (1993) versus those of Hildebrand et al. (1995). The size of a transient crater, such as the K/T extinction crater at Yucatan, Mexico, which is thought to be the source of SO,-induced sulfuric acid aerosol that globally acidified surface waters as the result of massive vaporization of CASO, in the target rock, is addressed by our present project. The impact process excavates samples of planetary interiors. The degree to which this occurs (e.g. how deeply does excavation occur for a given crater diameter) has been of interest, both with regard to exposing mantle rocks in crater floors, as well as launching samples into space which become part of the terrestrial meteorite collection (e.g. lunar meteorites, SNC's from Mars). Only in the case of the Earth can we test calculations in the laboratory and field. Previous calculations predict, independent of diameter, that the depth of excavation, normalized by crater diameter, is d(sub ex)/D = 0.085 (O'Keefe and Ahrens, 1993). For Comet Shoemaker-Levy 9 (SL9) fragments impacting Jupiter, predicted excavation depths of different gas-rich layers in the atmosphere, were much larger. The trajectory and fate of highly shocked material from a large impact on the Earth, such as the K/T bolide is of interest. Melosh et al. (1990) proposed that the condensed material from the impact upon reentering the Earth's atmosphere induced. radiative

  19. Optical Meteor Systems Used by the NASA Meteoroid Environment Office

    NASA Technical Reports Server (NTRS)

    Kingery, A. M.; Blaauw, R. C.; Cooke, W. J.; Moser, D. E.

    2015-01-01

    The NASA Meteoroid Environment Office (MEO) uses two main meteor camera networks to characterize the meteoroid environment: an all sky system and a wide field system to study cm and mm size meteors respectively. The NASA All Sky Fireball Network consists of fifteen meteor video cameras in the United States, with plans to expand to eighteen cameras by the end of 2015. The camera design and All-Sky Guided and Real-time Detection (ASGARD) meteor detection software [1, 2] were adopted from the University of Western Ontario's Southern Ontario Meteor Network (SOMN). After seven years of operation, the network has detected over 12,000 multi-station meteors, including meteors from at least 53 different meteor showers. The network is used for speed distribution determination, characterization of meteor showers and sporadic sources, and for informing the public on bright meteor events. The NASA Wide Field Meteor Network was established in December of 2012 with two cameras and expanded to eight cameras in December of 2014. The two camera configuration saw 5470 meteors over two years of operation with two cameras, and has detected 3423 meteors in the first five months of operation (Dec 12, 2014 - May 12, 2015) with eight cameras. We expect to see over 10,000 meteors per year with the expanded system. The cameras have a 20 degree field of view and an approximate limiting meteor magnitude of +5. The network's primary goal is determining the nightly shower and sporadic meteor fluxes. Both camera networks function almost fully autonomously with little human interaction required for upkeep and analysis. The cameras send their data to a central server for storage and automatic analysis. Every morning the servers automatically generates an e-mail and web page containing an analysis of the previous night's events. The current status of the networks will be described, alongside with preliminary results. In addition, future projects, CCD photometry and broadband meteor color camera

  20. Europa's Pwyll Crater

    NASA Technical Reports Server (NTRS)

    1998-01-01

    This view of the Pwyll impact crater on Jupiter's moon Europa taken by NASA's Galileo spacecraft shows the interior structure and surrounding ejecta deposits. Pwyll's location is shown in the background global view taken by Galileo's camera on December 16, 1997. Bright rays seen radiating from Pwyll in the global image indicate that this crater is geologically young. The rim of Pwyll is about 26 kilometers (16 miles) in diameter, and a halo of dark material excavated from below the surface extends a few kilometers beyond the rim. Beyond this dark halo, the surface is bright and numerous secondary craters can be seen. The closeup view of Pwyll, which combines imaging data gathered during the December flyby and the flyby of February 20, 1997, indicates that unlike most fresh impact craters, which have much deeper floors, Pwyll's crater floor is at approximately the same level as the surrounding background terrain.

    North is to the top of the picture and the sun illuminates the surface from the northeast. This closeup image, centered at approximately 26 degrees south latitude and 271 degrees west longitude, covers an area approximately 125 by 75 kilometers (75 by 45 miles). The finest details that can be discerned in this picture are about 250 meters (800 feet) across. This image was taken on at a range of 12,400 kilometers (7,400 miles), with the green filter of Galileo's solid state imaging system.

    The Jet Propulsion Laboratory, Pasadena, CA manages the Galileo mission for NASA's Office of Space Science, Washington, DC. JPL is an operating division of California Institute of Technology (Caltech).

    This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://www.jpl.nasa.gov/ galileo.

  1. ROAN Remote radio meteor detection sensor

    NASA Astrophysics Data System (ADS)

    Lesanu, C. E.

    2016-01-01

    Only few meteor enthusiasts across the world today, approaches systematically the radio meteor detection technique, one of the reasons being the difficulty to build and install proper permanent antennas, especially when low-VHF frequency opportunity transmitters are used as illuminators. Other reasons were in the past the relatively high cost of the entire system, receivers and computers, and not ultimately the high power consumption of the system in a 24/7 operation, when using regular personal computers. The situation changed in the recent years with the advent of the low cost software defined radio SDR receivers and low consumption/cost single board computers SBC. A commercial off-the-shelf hardware based remote radio meteor detection sensor is presented.

  2. SPA Meteor Section Results: Radio Draconids 2011

    NASA Astrophysics Data System (ADS)

    McBeath, Alastair

    2012-08-01

    Information determined from an analysis by the SPA Meteor Section of radio meteor data collected during the 2011 Draconid epoch is presented and discussed. A strong single maximum for the shower was found on October 8, with a mean time of 20 h05 m ± 5 m UT, and that activity was above half the maximum flux level between ˜ 19 h20 m to 20 h45 m UT. A comparison is given too with the IMO's preliminary visual and video findings, which suggested a quite close correlation between all three observing techniques in what was detected. A possibility that more somewhat larger particles/brighter meteors may have been present between ˜ 19 h40 m to 20 h20 m UT is noted too.

  3. Atmosphere dynamics in the equatorial meteor zone

    NASA Technical Reports Server (NTRS)

    Kascheev, B. L.

    1987-01-01

    The study of the atmospheric circulation of the Earth from its surface to the altitudes of 100 to 110 km is essential for establishing atmospheric motion regularities with a view toward perfecting weather forecasting. The main results of the Soviet equatorial meteor expedition (SEME) are presented. A continuous cycle of measurements was carried out. Considerable interdiurnal variation of the zonal component was observed. Importantly, in the meridional component, the prevalence of a two day component was established in the equatorial meteor zone for the first time. The pronounced westward motion of the atmosphere over the equator is noted. The SEME data analysis has shown that the meteor zone is characterized by flashes of intensity of the internal gravity waves and turbulence at highest instability moments of atmosphere due to tidal motion.

  4. Observation of meteors by MST radar

    NASA Technical Reports Server (NTRS)

    Jones, William; Kingsley, S. P.

    1992-01-01

    The observation of meteor trails by a vertical mesosphere - stratosphere - troposphere (MST) radar beam has the advantage of good height resolution and an approximate knowledge of the zenith angle since the trails are horizontal or near-horizontal. An extension of the ablation theory of meteors was developed for near horizontal trails which takes into account the curvature of the earth. Observations of the Geminid meteor shower by MST radar reveal the 'diffusion heights' to be in fair agreement with the true height, but with some discrepancies that can amount to 4 km. The true heights are almost entirely confined to the range 87-91 km, although the upper limit is attributed to the coherent integration time of the existing MST radar processing.

  5. Non-specular meteor trail diagnostics

    NASA Astrophysics Data System (ADS)

    Dyrud, L.; Oppenheim, M.; Close, S.; Ray, L.; McMillion, K.

    2003-12-01

    Plasma simulations demonstrate that meteor trails are unstable to growth of gradient-drift Farley-Buneman (GDFB) waves that become turbulent and generate large B-field aligned irregularities (FAI). These simulations and our analysis indicate that the non-specular echos, that can extend between 5-10 km in altitude range, are reflections from plasma instability generated FAI. We present models showing that the specific altitude range of trail instability depends on meteor and atmospheric properties. This variability will allow researchers to infer neutral temperature, neutral wind velocity, and meteoric velocity and composition in completely new ways. We demonstrate some of these non-specular trail diagnostic techniques using radar observations from the ALTAIR and Piura radar facilities. Finally, we present examples of a low altitude variety of non-specular echos that may be related to PMSE.

  6. SOFIE observations of PMCs and meteoric smoke

    NASA Astrophysics Data System (ADS)

    Hervig, M. E.; Gordley, L. L.; Russell, J.; Bailey, S. M.

    2010-12-01

    The Solar Occultation For Ice Experiment (SOFIE) has operated onboard the Aeronomy of Ice in the Mesosphere (AIM) satellite since May 2007. SOFIE uses solar occultation to measure vertical profiles of limb path atmospheric transmission within 16 spectral bands between 0.29 and 5.32 microns wavelength. SOFIE measurements are used to retrieve PMC extinction at ultraviolet (UV) through infrared (IR) wavelengths, meteoric smoke extinction at UV - near-IR wavelengths, temperature, and the abundance of five gaseous species (O3, H2O, CO2, CH4, and NO). Recent developments in understanding PMCs and meteoric smoke have been possible using SOFIE observations at 330 nm wavelength. These measurements provide information concerning PMC particle size, and also have provided observational evidence for the composition of meteoric smoke.

  7. SOFIE observations of PMCs and meteoric smoke

    NASA Astrophysics Data System (ADS)

    Hervig, Mark; Gordley, Larry; Russell, J. M., III; Bailey, Scott

    The Solar Occultation For Ice Experiment (SOFIE) has operated onboard the Aeronomy of Ice in the Mesosphere (AIM) satellite from May 2007 to present. SOFIE uses the technique of satel-lite solar occultation to measure vertical profiles of limb path atmospheric transmission within 16 spectral bands between 0.29 and 5.32 microns wavelength. SOFIE measurements are used to retrieve vertical profiles of polar mesospheric cloud (PMC) extinction at eleven wavelengths, temperature, meteoric smoke extinction, and the abundance of five gaseous species (O3, H2O, CO2, CH4, and NO). Recent developments in understanding PMCs and meteoric smoke have been possible using SOFIE observations at 0.330 microns wavelength. These measurements provide information concerning PMC particle size, and also have provided a new assessment of meteoric smoke in the northern hemisphere.

  8. All-sky Meteor Orbit System AMOS and preliminary analysis of three unusual meteor showers

    NASA Astrophysics Data System (ADS)

    Tóth, Juraj; Kornoš, Leonard; Zigo, Pavol; Gajdoš, Štefan; Kalmančok, Dušan; Világi, Jozef; Šimon, Jaroslav; Vereš, Peter; Šilha, Jiří; Buček, Marek; Galád, Adrián; Rusňák, Patrik; Hrábek, Peter; Ďuriš, František; Rudawska, Regina

    2015-12-01

    All-sky Meteor Orbit System (AMOS) is a semi-autonomous video observatory for detection of transient events on the sky, mostly the meteors. Its hardware and software development and permanent placement on several locations in Slovakia allowed the establishment of Slovak Video Meteor Network (SVMN) monitoring meteor activity above the Central Europe. The data reduction, orbital determination and additional results from AMOS cameras - the SVMN database - as well as from observational expeditions on Canary Islands and in Canada provided dynamical and physical data for better understanding of mutual connections between parent bodies of asteroids and comets and their meteoroid streams. We present preliminary results on exceptional and rare meteor streams such as September ɛ Perseids (SPE) originated from unknown long periodic comet on a retrograde orbit, suspected asteroidal meteor stream of April α Comae Berenicids (ACO) in the orbit of meteorites Příbram and Neuschwanstein and newly observed meteor stream Camelopardalids (CAM) originated from Jupiter family comet 209P/Linear.

  9. Various meteor scenes I: the perception and the conception of a 'meteor shower'

    NASA Astrophysics Data System (ADS)

    Koseki, Masahiro

    2014-10-01

    Not all 'established showers' are recognisable by every method. Some might be lost ('dead') or have recurrent (periodic) nature and are not observable annually. Some are dominated by faint meteors and not observable visually but by radar systems. Other showers are rich in fireballs and their low meteor rates make them a good target for video and photographic observations, while visual observers may not notice their activity because of the low rates. The perception limit in magnitude differs between the observing methods on the one hand, but depends on the magnitude ratios of shower meteors on the other hand. Differences in the definition of a 'meteor shower'/'meteoroid stream' work important roles composing the shower list and we need to know how much various researchers' definitions differ. Depending whether we use observational raw data of the visible meteor shower or orbital elements of the meteoroid stream this may lead to either an obvious meteor showers or an undetectable stream. This paper (paper I) describes the reasons why we can see a meteor shower and why not, Paper II proves the condition by the example of Cygnid-Draconid complex, especially for the κ-Cygnids, and Paper III looks at the different views of several minor showers from the different kind observations.

  10. 'Erebus Crater' on the Horizon

    NASA Technical Reports Server (NTRS)

    2005-01-01

    This is a mosaic assembled from some of the images taken by the panoramic camera on NASA's Mars Exploration Rover Opportunity during the rover's 590th sol (Sept. 21, 2005). The view is toward the south and includes rock exposures north of 'Erebus Crater,' with the crater in the background. The rover will investigate the exposed rocks in the foreground and will take additional panoramic-camera images of Erebus Crater, which is about 300 meters (about 984 feet) across.

    Erebus Crater dwarfs the landing-site crater, 'Eagle Crater,' which measures about 22 meters (72 feet) in diameter. And, it is nearly twice the diameter of 'Endurance Crater,' which, at 130 meters (430 feet) wide, has been compared to a stadium.

    The camera's red filter was used for taking the images in this mosaic. It admits light with a wavelength of 750 nanometers.

  11. The First Year of Croatian Meteor Network

    NASA Astrophysics Data System (ADS)

    Andreic, Zeljko; Segon, Damir

    2010-08-01

    The idea and a short history of Croatian Meteor Network (CMN) is described. Based on use of cheap surveillance cameras, standard PC-TV cards and old PCs, the Network allows schools, amateur societies and individuals to participate in photographic meteor patrol program. The network has a strong educational component and many cameras are located at or around teaching facilities. Data obtained by these cameras are collected and processed by the scientific team of the network. Currently 14 cameras are operable, covering a large part of the croatian sky, data gathering is fully functional, and data reduction software is in testing phase.

  12. CCTV lenses for video meteor astronomy

    NASA Astrophysics Data System (ADS)

    Wiśniewski, M.; Olech, A.; Krasnowski, M.; Zloczewski, K.; Mularczyk, K.; Kedzierski, P.; Jonderko, W.

    2005-02-01

    We present the results of CCTV lens tests made last year at the Ostrowik Observatory by observers of the Comets and Meteors Workshop. A total of 13 lenses with different parameters were tested. The limiting magnitudes, size of field of view, distortion and off-axis aberrations were measured. The Computar f/1.2, f=4 mm appeared to be the best lens tested. We also note the good marks of both Ernitecs which were finally chosen as the lenses which will be used in our projects. Surprisingly, the very fast lenses which are popular in video meteor astronomy seem to be much worse that their f/1.2 rivals.

  13. Meteor spectra from AMOS video system

    NASA Astrophysics Data System (ADS)

    Gajdoš, Š.; Tóth, J.; Kornoš, L.

    2015-01-01

    We present a report on the observation of enhanced activity from the Ursids meteor shower using the all-sky camera, at the AGO Modra, on Dec. 22-23, 2014. The time of maximum is in good accordance with the predictions of some authors. We derived a single-station meteor radiant, RA = 217.9° ± 0.1°, DEC = +76.4° ± 0.1° at solar longitude S.L. = 270.9°, along with the activity profile of the Ursid outburst with the maximum occurring at Dec. 23th, 00h40m UT ± 30 min.

  14. In Situ Measurements of Meteoric Ions

    NASA Technical Reports Server (NTRS)

    Grebowsky, Joseph M.; Aiken, Arthur C.; Einaudi, Franco (Technical Monitor)

    2001-01-01

    Extraterrestrial material is the source of metal ions in the Earth's atmosphere, Each year approx. 10(exp 8) kg of material is intercepted by the Earth. The origin of this material is predominantly solar orbiting interplanetary debris from comets or asteroids that crosses the Earth's orbit. It contains a very small amount of interstellar material. On occasion the Earth passes through enhanced amounts of debris associated with the orbit of a decaying comet. This leads to enhanced meteor shower displays for up to several days. The number flux of shower material is typically several times the average sporadic background influx of material. Meteoric material is some of the earliest material formed in the solar system. By studying the relative elemental abundances of atmospheric metal ions, information can be gained on the chemical composition of cometary debris and the chemical makeup of the early solar system. Using in situ sampling with rocket-borne ion mass spectrometers; there have been approximately 50 flights that made measurements of the metal ion abundances at attitudes between 80 and 130 km. It is this altitude range where incoming meteoric particles am ablated, the larger ones giving rise to visible meteor. displays. In several rocket measurements isotopic ratios of different atomic ion mass components and metal molecular ion concentrations have been determined and used to identify unambiguously the measured species and to investigate the processes controlling the metal ion distributions The composition of the Earth's ionosphere was first sampled by an ion mass spectrometer flown an a rocket in 1956. In 1958 a rocket-borne ion spectrometer identified, fbr the first time, a layer of metal ions near 95 km. These data were interpreted as evidence of an extraterrestrial rather than a terrestrial source. Istomin predicted: "It seems probable that with some improvement in the method that analysis of the ion composition in the E-region may be used for determining

  15. Meteor spectra from AMOS video system

    NASA Astrophysics Data System (ADS)

    Rudawska, Regina; Tóth, Juraj; Kalmančok, Dušan; Zigo, Pavol; Matlovič, Pavol

    2016-04-01

    Here we demonstrate the capability of the updated All-Sky Meteor Orbit System (AMOS) (called AMOS-Spec) to measure the main element abundances of meteors. The AMOS-Spec program has been created with the intention of carrying out regular systematic spectroscopic observations. At the same time, the meteoroid trajectory and pre-atmospheric orbit are independently measured from data collected by the AMOS camera network. This, together with spectral information, allows us to find the link between the meteoroid and its parent body, from both dynamical and physical consideration. Here we report results for 35 selected cases.

  16. The Radio Meteor Zoo: a citizen science project

    NASA Astrophysics Data System (ADS)

    Calders, S.; Verbeeck, C.; Lamy, H.; Martínez Picar, A.

    2016-01-01

    Scientists from the BRAMS radio meteor network have started a citizen science project called Radio Meteor Zoo in collaboration with Zooniverse in order to identify meteor reflections in BRAMS spectrograms. First, a small-scale version of the Radio Meteor Zoo was carried out with a sample of meteor identifications in 12 spectrograms by 35 volunteers. Results are presented here and allowed us to define a method that reliably detects meteor reflections based on the identifications by the volunteers. It turns out that, if each spectrogram is inspected by 10 volunteers, hit and false detection percentages of 95% respectively 6% are expected. The Radio Meteor Zoo is online at https://www.zooniverse.org/projects/zooniverse/radio-meteor-zoo. Citizen scientists are kindly invited to inspect spectrograms.

  17. Exploring the relationship between meteor parameters based on photographic data

    NASA Astrophysics Data System (ADS)

    Yancheva, Y.; Hristova, S.; Bojurova, E.

    2016-01-01

    The paper presents an attempt to investigate the relationship between the luminosity and the linear length of the meteors, based on photographic observations of the Geminid meteor shower during the night of maximum in December 2015.

  18. Independent identification of meteor showers in EDMOND database

    NASA Astrophysics Data System (ADS)

    Rudawska, R.; Matlovič, P.; Tóth, J.; Kornoš, L.

    2015-12-01

    Cooperation and data sharing among national networks and International Meteor Organization Video Meteor Database (IMO VMDB) resulted in European viDeo MeteOr Network Database (EDMOND). The current version of the database (EDMOND 5.0) contains 144 749 orbits collected from 2001 to 2014. This paper presents the results obtained by a proposed new independent method of meteor showers identification, which is applied to the current version of the database (EDMOND 5.0). In the first step of the survey we used the DSH criterion to find groups around each meteor within the similarity threshold. Mean parameters of the groups were calculated and compared using a new function DX based on geocentric parameters (λ⊙, α, δ, and Vg). Similar groups were merged into final clusters (representing meteor showers), and compared with the IAU Meteor Data Center list of meteor showers.

  19. Central pit craters on Ganymede

    NASA Astrophysics Data System (ADS)

    Alzate, Nathalia; Barlow, Nadine G.

    2011-02-01

    Central pit craters are common on Mars, Ganymede and Callisto, and thus are generally believed to require target volatiles in their formation. The purpose of this study is to identify the environmental conditions under which central pit craters form on Ganymede. We have conducted a study of 471 central pit craters with diameters between 5 and 150 km on Ganymede and compared the results to 1604 central pit craters on Mars (diameter range 5-160 km). Both floor and summit pits occur on Mars whereas floor pits dominate on Ganymede. Central peak craters are found in similar locations and diameter ranges as central pit craters on Mars and overlap in location and at diameters <60 km on Ganymede. Central pit craters show no regional variations on either Ganymede or Mars and are not concentrated on specific geologic units. Central pit craters show a range of preservation states, indicating that conditions favoring central pit formation have existed since crater-retaining surfaces have existed on Ganymede and Mars. Central pit craters on Ganymede are generally about three times larger than those on Mars, probably due to gravity scaling although target characteristics and resolution also may play a role. Central pits tend to be larger relative to their parent crater on Ganymede than on Mars, probably because of Ganymede's purer ice crust. A transition to different characteristics occurs in Ganymede's icy crust at depths of 4-7 km based on the larger pit-to-crater-diameter relationship for craters in the 70-130-km-diameter range and lack of central peaks in craters larger than 60-km-diameter. We use our results to constrain the proposed formation models for central pits on these two bodies. Our results are most consistent with the melt-drainage model for central pit formation.

  20. Arizona's Community Colleges in 2010.

    ERIC Educational Resources Information Center

    Puyear, Don

    This report provides a vision of what community colleges in Arizona, and elsewhere, may look like in 2010. The observations are based on the results of a meeting held by the Committee on the Future of Arizona Community Colleges, on reading and conversations related to the work of Arizona Learning Systems, and the paper's general observations of…

  1. Optical studies of meteors at Mount Hopkins Observatory

    NASA Technical Reports Server (NTRS)

    Weekes, T. C.; Williams, J. T.

    1974-01-01

    The 10-m optical reflector and an array of phototubes are used to extend the optical measurements beyond the present limit achieved by the Vidicon system. The first detection of optical meteors with M sub v = + 12 is reported. It is hoped that this system can be used to determine intermediate points in the meteor frequency mass curve for sporadic meteors and to study in detail the faint components of meteor showers. Preliminary observations made on three nights in September 1974 are presented.

  2. The I.A.U. meteor shower nomenclature rules

    NASA Astrophysics Data System (ADS)

    Jenniskens, Peter

    2006-10-01

    The International Astronomical Union at its 2006 General Assembly in Prague has adopted a set of rules for meteor shower nomenclature, a working list with designated names (with IAU numbers and three-letter codes), and established a Task Group for Meteor Shower Nomenclature in Commission 22 (Meteors and Interplanetary Dust) to help define which meteor showers exist from well defined groups of meteoroids from a single parent body.

  3. Meteor Search by Spirit, Sol 668

    NASA Technical Reports Server (NTRS)

    2005-01-01

    [figure removed for brevity, see original site] Annotated Meteor Search by Spirit, Sol 668

    The panoramic cameras on NASA's Mars Exploration Rovers are about as sensitive as the human eye at night. The cameras can see the same bright stars that we can see from Earth, and the same patterns of constellations dot the night sky. Scientists on the rover team have been taking images of some of these bright stars as part of several different projects. One project is designed to try to capture 'shooting stars,' or meteors, in the martian night sky. 'Meteoroids' are small pieces of comets and asteroids that travel through space and eventually run into a planet. On Earth, we can sometimes see meteoroids become brilliant, long 'meteors' streaking across the night sky as they burn up from the friction in our atmosphere. Some of these meteors survive their fiery flight and land on the surface (or in the ocean) where, if found, they are called 'meteorites.' The same thing happens in the martian atmosphere, and Spirit even accidentally discovered a meteor while attempting to obtain images of Earth in the pre-dawn sky back in March, 2004 (see http://marsrovers.jpl.nasa.gov/gallery/press/spirit/20040311a.html, and Selsis et al. (2005) Nature, vol 435, p. 581). On Earth, some meteors come in 'storms' or 'showers' at predictable times of the year, like the famous Perseid meteor shower in August or the Leonid meteor shower in November. These 'storms' happen when Earth passes through the same parts of space where comets sometimes pass. The meteors we see at these times are from leftover debris that was shed off of these comets.

    The same kind of thing is predicted for Mars, as well. Inspired by calculations about Martian meteor storms by meteor scientists from the University of Western Ontario in Canada and the Centre de Recherche en Astrophysique de Lyon in France, and also aided by other meteor research colleagues from NASA's Marshall Space Flight Center, scientists on

  4. Determination of meteor flux distribution over the celestial sphere

    NASA Technical Reports Server (NTRS)

    Andreev, V. V.; Belkovich, O. I.; Filimonova, T. K.; Sidorov, V. V.

    1992-01-01

    A new method of determination of meteor flux density distribution over the celestial sphere is discussed. The flux density was derived from observations by radar together with measurements of angles of arrival of radio waves reflected from meteor trails. The role of small meteor showers over the sporadic background is shown.

  5. A parent body search across several video meteor data bases

    NASA Astrophysics Data System (ADS)

    Šegon, D.; Gural, P.; Andreić, Ž.; Skokić, I.; Korlević, K.; Vida, D.; Novoselnik, F.

    2014-07-01

    A meteor stream search that uses all the known near-Earth objects (NEOs) as parent bodies, with their individual orbital elements as the starting point, has found statistically significant associations when applied to video meteor data bases. By using the combined CMN-SonotaCo data sets containing 133,652 video meteor orbits, 30 comets were associated with meteor showers of which only 23 were previously listed in the IAU MDC data base. Additionally, 43 asteroids with inclinations over 15 degrees may be associated to streams containing ten or more meteor orbits, each possibly representing a new meteor shower. Lastly, by using a modified search that compared the orbital similarity of each meteor to all other video meteors in the data base, 1093 groupings with more than ten meteors were found that may be indicative of several new minor showers. Of those groups, 6 new showers were found to be potentially associated to a parent body. Several dozen additional groups are planned for publication and submittal to the IAU for their consideration as newly discovered streams. Altogether 56,486 (42%) of the meteors in the combined video meteor data base are in one of the meteor stream groupings found, while the rest are likely sporadics. Further analysis is needed to prove that the groupings found are indeed minor showers.

  6. Results of the IMO Video Meteor Network - October 2014

    NASA Astrophysics Data System (ADS)

    Molau, Sirko; Kac, Javor; Crivello, Stefano; Stomeo, Enrico; Barentsen, Geert; Goncalves, Rui; Saraiva, Carlos; Maciewski, Maciej; Maslov, Mikhail

    2015-02-01

    A record number of 86 cameras of the IMO Video Meteor Network collected over 11 000 hours worth of data in 2014 October, recording almost 52 000 meteors. Yearly flux density profiles are presented for the Orionids, Leonis Minorids, October Camelopardalids, and October Ursae Majorids, covering the period from 2011 to 2014. Population indexes are calculated for all four meteor showers.

  7. The activity of autumn meteor showers in 2006-2008

    NASA Astrophysics Data System (ADS)

    Kartashova, Anna

    2015-03-01

    The purpose of meteor observations in INASAN is the study of meteor showers, as the elements of the migrant substance of the Solar System, and estimation of risk of hazardous collisions of spacecrafts with the particles of streams. Therefore we need to analyze the meteor events with brightness of up to 8 m, which stay in meteoroid streams for a long time and can be a hazardous for the spacecraft. The results of our single station TV observations of autumn meteor showers for the period from 2006 to 2008 are presented. The high-sensitive hybrid camera (the system with coupled of the Image Intensifier) FAVOR with limiting magnitude for meteors about 9m. . .10m in the field of view 20 × 18 was used for observations. In 2006-2008 from October to November more than 3 thousand of meteors were detected, 65% from them have the brightness from 6m to 9m. The identification with autumn meteor showers (Orionids, Taurids, Draconids, Leonids) was carried out. In order to estimate the density of the influx of meteor matter to the Earth for these meteor showers the Index of meteor activity (IMA) was calculated. The IMA distribution for the period 2006 - 2008 is given. The distributions of autumn meteor showers (the meteors with brightness of up to 8 m) by stellar magnitude from 2006 to 2008 are also presented.

  8. 47 CFR 90.250 - Meteor burst communications.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 5 2011-10-01 2011-10-01 false Meteor burst communications. 90.250 Section 90... PRIVATE LAND MOBILE RADIO SERVICES Non-Voice and Other Specialized Operations § 90.250 Meteor burst communications. Meteor burst communications may be authorized for the use of private radio stations subject...

  9. 47 CFR 90.250 - Meteor burst communications.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 5 2014-10-01 2014-10-01 false Meteor burst communications. 90.250 Section 90... PRIVATE LAND MOBILE RADIO SERVICES Non-Voice and Other Specialized Operations § 90.250 Meteor burst communications. Meteor burst communications may be authorized for the use of private radio stations subject...

  10. 47 CFR 90.250 - Meteor burst communications.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 5 2013-10-01 2013-10-01 false Meteor burst communications. 90.250 Section 90... PRIVATE LAND MOBILE RADIO SERVICES Non-Voice and Other Specialized Operations § 90.250 Meteor burst communications. Meteor burst communications may be authorized for the use of private radio stations subject...

  11. 47 CFR 90.250 - Meteor burst communications.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 5 2010-10-01 2010-10-01 false Meteor burst communications. 90.250 Section 90... PRIVATE LAND MOBILE RADIO SERVICES Non-Voice and Other Specialized Operations § 90.250 Meteor burst communications. Meteor burst communications may be authorized for the use of private radio stations subject...

  12. 47 CFR 90.250 - Meteor burst communications.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 5 2012-10-01 2012-10-01 false Meteor burst communications. 90.250 Section 90... PRIVATE LAND MOBILE RADIO SERVICES Non-Voice and Other Specialized Operations § 90.250 Meteor burst communications. Meteor burst communications may be authorized for the use of private radio stations subject...

  13. Easy way to estimate meteor brightness on TV frames

    NASA Astrophysics Data System (ADS)

    Leonov, V. A.; Bagrov, A. V.

    2016-01-01

    The traditional method of the meteor brightness measurements claims that the meteor brightness is equal to the stellar magnitude of a star that looks like a meteor in the brightest point of its track. This rule was convenient for the comparison of meteor observations by different observers and for the analysis of the brightness distributions of meteors from observed showers. This traditional method suffers from systematic errors, particularly those that arise from using stellar brightness measured in specific spectral wave bands different from the observer's ones, but mainly due to neglecting the influence of the meteor angular velocity on the real meteor brightness. To get a proper estimate of the meteor brightness that is a measure of the ground meteor illumination in the non-systematic units, an observer must take into account that the effective exposition of a meteor image in any resolution element of its track is a few times shorter than the corresponding exposition of a star image in the same frame. We propose a very simple method for improved estimations of meteor brightness by applying a correction to the meteor stellar magnitude obtained within the traditional framework.

  14. Results of the IMO Video Meteor Network - June 2015

    NASA Astrophysics Data System (ADS)

    Molau, Sirko; Kac, Javor; Crivello, Stefano; Stomeo, Enrico; Barentsen, Geert; Goncalves, Rui; Saraiva, Carlos; Maciejewski, Maciej; Maslov, Mikhail

    2015-10-01

    Observations of the IMO Video Meteor Network are presented for 2015 June. Activity profile is presented for the Daytime Arietids, based on 28 shower meteors. The meteor rate of the Daytime Arietids between June 5 and 11, normalized for the limiting magnitude and angular velocity, is found to be about one quarter of that of the eta-Aquariids during their maximum.

  15. Layers in Terby Crater

    NASA Technical Reports Server (NTRS)

    2003-01-01

    MGS MOC Release No. MOC2-407, 30 June 2003

    Whether on Earth or Mars, sedimentary rocks provide a record of past environments. Of course, it is difficult to read that record without being able to visit the site. However, the Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) has revealed hundreds of locales on Mars at which sedimentary rocks are exposed at the surface. Terby Crater exhibits hundreds of layers of similar thickness and physical properties--some have speculated these may be the record of an ancient lake or sea. This MOC image shows some of the layer outcrops in Terby Crater. Fans of debris have eroded from the steep, layered slopes in some places. This picture covers an area 3 km (1.9 mi) wide near 27.5oS, 285.7oW. The image is illuminated from the upper left and was obtained in June 2003.

  16. Exhumed Arabian Crater

    NASA Technical Reports Server (NTRS)

    2004-01-01

    26 August 2004 Eastern Arabia Terra shares many attributes with western Arabia and Sinus Meridiani. In particular, it is a region of vast layered rock within which are interbedded filled and buried craters and valleys. Erosion has subsequently re-exposed many of these landforms, including the exhumed and eroded crater shown in this Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image. Following the period in which erosion occurred, the region was blanketed by dust. This image is located near 22.5oN, 318.4oW, and covers an area about 3 km (1.9 mi) across. Sunlight illuminates the scene from the left/lower left.

  17. The LCROSS cratering experiment.

    PubMed

    Schultz, Peter H; Hermalyn, Brendan; Colaprete, Anthony; Ennico, Kimberly; Shirley, Mark; Marshall, William S

    2010-10-22

    As its detached upper-stage launch vehicle collided with the surface, instruments on the trailing Lunar Crater Observation and Sensing Satellite (LCROSS) Shepherding Spacecraft monitored the impact and ejecta. The faint impact flash in visible wavelengths and thermal signature imaged in the mid-infrared together indicate a low-density surface layer. The evolving spectra reveal not only OH within sunlit ejecta but also other volatile species. As the Shepherding Spacecraft approached the surface, it imaged a 25- to-30-meter-diameter crater and evidence of a high-angle ballistic ejecta plume still in the process of returning to the surface--an evolution attributed to the nature of the impactor. PMID:20966243

  18. Perseid meteor shower in 2012--2013 by TV meteor observations

    NASA Astrophysics Data System (ADS)

    Kartashova, A.; Bolgova, G.

    2014-07-01

    We present results of TV observations that were obtained during the Perseid meteor shower activity (18 July -- 19 August) in 2012 and 2013. The observations were carried out in Moscow region using the TV system PatrolCa with FOV of 50°×40° and a limiting magnitude (for meteors) of 4^m--5^m [1]. The individual radiants of Perseid meteors and the radiant drift (for 2012--2013) are given. The Perseids orbits obtained by double-station observations are shown. The brightness distributions of the Perseids are also presented. The maximum activity occurs at 12 August with the Index of Meteor Activity (particles to the Earth per 1 hour [2,3]) of 7×10^4 in 2012 and 1×10^4 in 2013. An additional peak was detected in 10 August 2013. The distributions of IMA for 2012--2013 Perseids are presented.

  19. Meteor Shower Activity Derived from "Meteor Watching Public-Campaign" in Japan

    NASA Technical Reports Server (NTRS)

    Sato, M.; Watanabe, J.

    2011-01-01

    We tried to analyze activities of meteor showers from accumulated data collected by public campaigns for meteor showers which were performed as outreach programs. The analyzed campaigns are Geminids (in 2007 and 2009), Perseids (in 2008 and 2009), Quadrantids (in 2009) and Orionids (in 2009). Thanks to the huge number of reports, the derived time variations of the activities of meteor showers is very similar to those obtained by skilled visual observers. The values of hourly rates are about one-fifth (Geminids 2007) or about one-fourth (Perseids 2008) compared with the data of skilled observers, mainly due to poor observational sites such as large cities and urban areas, together with the immature skill of participants in the campaign. It was shown to be highly possible to estimate time variation in the meteor shower activity from our campaign.

  20. Callisto Crater Chain Mosaic

    NASA Technical Reports Server (NTRS)

    1997-01-01

    This mosaic of three images shows an area within the Valhalla region on Jupiter's moon, Callisto. North is to the top of the mosaic and the Sun illuminates the surface from the left. The smallest details that can be discerned in this picture are knobs and small impact craters about 160 meters (175 yards) across. The mosaic covers an area approximately 45 kilometers (28 miles) across. It shows part of a prominent crater chain located on the northern part of the Valhalla ring structure.

    Crater chains can form from the impact of material ejected from large impacts (forming secondary chains) or by the impact of a fragmented projectile, perhaps similar to the Shoemaker-Levy 9 cometary impacts into Jupiter in July 1994. It is believed this crater chain was formed by the impact of a fragmented projectile. The images which form this mosaic were obtained by the solid state imaging system aboard NASA's Galileo spacecraft on Nov. 4, 1996 (Universal Time).

    Launched in October 1989, Galileo entered orbit around Jupiter on December 7, 1995. The spacecraft's mission is to conduct detailed studies of the giant planet, its largest moons and the Jovian magnetic environment. The Jet Propulsion Laboratory, Pasadena, CA manages the mission for NASA's Office of Space Science, Washington, DC.

    This image and other images and data received from Galileo are posted on the World Wide Web Galileo mission home page at http://galileo.jpl.nasa.gov. Background information and educational context for the images can be found at http:// www.jpl.nasa.gov/galileo/sepo.

  1. Craters and Winds

    NASA Technical Reports Server (NTRS)

    2005-01-01

    8 April 2005 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows craters with wind streaks in Acidalia Planitia. The winds responsible for the streaks blew from the upper right (northeast).

    Location near: 37.1oN, 36.8oW Image width: 3 km (1.9 mi) Illumination from: lower left Season: Northern Summer

  2. Lohse Crater Dunes

    NASA Technical Reports Server (NTRS)

    2005-01-01

    8 January 2004 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows windblown sand dunes in Lohse Crater in Noachis Terra near 43.8oS, 16.8oW. The winds responsible for these dunes blew largely from the lower left (southwest) toward the upper right (northeast). The picture covers an area about 3 km (1.9 mi) across, and is illuminated by sunlight from the upper left.

  3. Crater in Sabaeus

    NASA Technical Reports Server (NTRS)

    2005-01-01

    12 October 2005 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a portion of an old impact crater in the Sinus Sabaeus region of Mars, just south of the large impact basin, Schiaparelli.

    Location near: 6.3oS, 341.7oW Image width: width: 3 km (1.9 mi) Illumination from: lower left Season: Southern Spring

  4. Small Craters on Europa

    NASA Technical Reports Server (NTRS)

    1998-01-01

    This high resolution view of the Conamara Chaos region on Jupiter's icy moon, Europa, reveals craters which range in size from about 30 meters to over 450 meters (slightly over a quarter of a mile) in diameter. The large number of craters seen here is unusual for Europa. This section of Conamara Chaos lies inside a bright ray of material which was ejected by the large impact crater, Pwyll, 1000 kilometers (620 miles) to the south. The presence of craters within the bright ray suggests that many are secondaries which formed from chunks of material that were thrown out by the enormous energy of the impact which formed Pwyll.

    North is to the upper right of the picture and the sun illuminates the surface from the east. The image, centered at 9 degrees latitude and 274 degrees longitude, covers an area approximately 8 by 4 kilometers (5 by 2.5 miles). The finest details that can be discerned in this picture are about 20 meters (66 feet) across. The images were taken on December 16, 1997 at a range of 960 kilometers (590 miles) by the Solid State Imaging (SSI) system on NASA's Galileo spacecraft.

    The Jet Propulsion Laboratory, Pasadena, CA manages the Galileo mission for NASA's Office of Space Science, Washington, DC. JPL is an operating division of California Institute of Technology (Caltech).

    This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://galileo.jpl.nasa.gov. Background information and educational context for the images can be found at URL http://www.jpl.nasa.gov/galileo/sepo

  5. Automated Meteor Fluxes with a Wide-Field Meteor Camera Network

    NASA Technical Reports Server (NTRS)

    Blaauw, R. C.; Campbell-Brown, M. D.; Cooke, W.; Weryk, R. J.; Gill, J.; Musci, R.

    2013-01-01

    Within NASA, the Meteoroid Environment Office (MEO) is charged to monitor the meteoroid environment in near ]earth space for the protection of satellites and spacecraft. The MEO has recently established a two ]station system to calculate automated meteor fluxes in the millimeter ]size ]range. The cameras each consist of a 17 mm focal length Schneider lens on a Watec 902H2 Ultimate CCD video camera, producing a 21.7 x 16.3 degree field of view. This configuration has a red ]sensitive limiting meteor magnitude of about +5. The stations are located in the South Eastern USA, 31.8 kilometers apart, and are aimed at a location 90 km above a point 50 km equidistant from each station, which optimizes the common volume. Both single station and double station fluxes are found, each having benefits; more meteors will be detected in a single camera than will be seen in both cameras, producing a better determined flux, but double station detections allow for non ]ambiguous shower associations and permit speed/orbit determinations. Video from the cameras are fed into Linux computers running the ASGARD (All Sky and Guided Automatic Real ]time Detection) software, created by Rob Weryk of the University of Western Ontario Meteor Physics Group. ASGARD performs the meteor detection/photometry, and invokes the MILIG and MORB codes to determine the trajectory, speed, and orbit of the meteor. A subroutine in ASGARD allows for the approximate shower identification in single station meteors. The ASGARD output is used in routines to calculate the flux in units of #/sq km/hour. The flux algorithm employed here differs from others currently in use in that it does not assume a single height for all meteors observed in the common camera volume. In the MEO system, the volume is broken up into a set of height intervals, with the collecting areas determined by the radiant of active shower or sporadic source. The flux per height interval is summed to obtain the total meteor flux. As ASGARD also

  6. Meteor spectroscopy during the 2015 Quadrantids

    NASA Astrophysics Data System (ADS)

    Ward, Bill

    2015-08-01

    Spectroscopic video observations during the Quadrantid meteor shower 2015 were made with Watec low light level video cameras fitted with 12 mm f/0.8 lenses carrying 50 mm square diffraction gratings. Four spectra with adequate signal to noise ratios were captured and the results analysed and discussed.

  7. Bright Meteor Lights Up Atlanta Skies

    NASA Video Gallery

    This video shows a very bright meteor that streaked over the skies of Atlanta, Ga., on the night of Aug. 28, 2011. The view is from an all sky camera in Cartersville, Ga., operated by NASA’s Mars...

  8. Meteor Observation and the Light Pollution

    NASA Astrophysics Data System (ADS)

    Grigore, Valentin

    2010-01-01

    This paper propose some concrete ways and procedures made by "no light pollution" militants (astronomers, ecologists, scientific, educational and cultural institutions) to combat this type of pollution. Meteor observations is the most important field of astronomy affected by the light pollution.

  9. Lake Erie Fireball Meteor, Tavistock View

    NASA Video Gallery

    This brief video shows a view of the Aug 8 fireball meteor that entered the atmosphere 54 miles above Lake Erie and moved SSE at 25 km/s, or 55,900 mph. This view is from the all sky camera in Tavi...

  10. Lake Erie Fireball Meteor, Mcmaster View

    NASA Video Gallery

    This brief video shows a view of the Aug 8 fireball meteor that entered the atmosphere 54 miles above Lake Erie and moved SSE at 25 km/s, or 55,900 mph. This view is from the all sky camera in Mcma...

  11. Lake Erie Fireball Meteor, Orangeville View

    NASA Video Gallery

    This brief video shows a view of the Aug 8 fireball meteor that entered the atmosphere 54 miles above Lake Erie and moved SSE at 25 km/s, or 55,900 mph. This view is from the all sky camera in Oran...

  12. BRAMS --- the Belgian RAdio Meteor Stations

    NASA Astrophysics Data System (ADS)

    Lamy, H.; Ranvier, S.; Martinez Picar, A.; Gamby, E.; Calders, S.; Anciaux, M.; De Keyser, J.

    2014-07-01

    BRAMS is a new radio observing facility developed by the Belgian Institute for Space Aeronomy (BISA) to detect and characterize meteors using forward scattering. It consists of a dedicated beacon located in the south-east of Belgium and in 25 identical receiving stations spread over the Belgian territory. The beacon transmits a pure sinusoidal wave at a frequency of 49.97 MHz with a power of 150 watts. A complete description of the BRAMS network and the data produced will be provided. The main scientific goals of the project are to compute fluxes, retrieve trajectories of individual objects, and determine physical parameters (speed, ionization, mass) for some of the observed meteor echoes. All these goals require a good knowledge of the radiation patterns of the transmitting and receiving antennas. Simulations have been made and will be validated with in-situ measurements using a UAV/drone equipped with a transmitter flying in the far-field region. The results will be provided. Each receiving station generates around 1 GB of data per day with typical numbers of sporadic meteor echoes of 1500--2000. An automatic detection method of these meteor echoes is therefore mandatory but is complicated by spurious echoes mostly due to airplanes. The latest developments of this automatic detection method will be presented and compared to manual counts for validation. Strong and weak points of the method will be presented as well as a possible alternative method using neural networks.

  13. Meteor Search by Spirit, Sol 668

    NASA Technical Reports Server (NTRS)

    2005-01-01

    [figure removed for brevity, see original site] Annotated Meteor Search by Spirit, Sol 668

    The panoramic cameras on NASA's Mars Exploration Rovers are about as sensitive as the human eye at night. The cameras can see the same bright stars that we can see from Earth, and the same patterns of constellations dot the night sky. Scientists on the rover team have been taking images of some of these bright stars as part of several different projects. One project is designed to try to capture 'shooting stars,' or meteors, in the martian night sky. 'Meteoroids' are small pieces of comets and asteroids that travel through space and eventually run into a planet. On Earth, we can sometimes see meteoroids become brilliant, long 'meteors' streaking across the night sky as they burn up from the friction in our atmosphere. Some of these meteors survive their fiery flight and land on the surface (or in the ocean) where, if found, they are called 'meteorites.' The same thing happens in the martian atmosphere, and Spirit even accidentally discovered a meteor while attempting to obtain images of Earth in the pre-dawn sky back in March, 2004 (see http://marsrovers.jpl.nasa.gov/gallery/press/spirit/20040311a.html, and Selsis et al. (2005) Nature, vol 435, p. 581). On Earth, some meteors come in 'storms' or 'showers' at predictable times of the year, like the famous Perseid meteor shower in August or the Leonid meteor shower in November. These 'storms' happen when Earth passes through the same parts of space where comets sometimes pass. The meteors we see at these times are from leftover debris that was shed off of these comets.

    The same kind of thing is predicted for Mars, as well. Inspired by calculations about Martian meteor storms by meteor scientists from the University of Western Ontario in Canada and the Centre de Recherche en Astrophysique de Lyon in France, and also aided by other meteor research colleagues from NASA's Marshall Space Flight Center, scientists on

  14. Arizona's Application Service Provider.

    ERIC Educational Resources Information Center

    Jordan, Darla

    2002-01-01

    Describes the U.S.'s first statewide K-12 application service provider (ASP). The ASP, implemented by the Arizona School Facilities Board, provides access to productivity, communications, and education software programs from any Internet-enabled device, whether in the classroom or home. (EV)

  15. Arizona State University. Exemplars.

    ERIC Educational Resources Information Center

    Wegner, Gregory R.

    This report discusses how the Arizona Board of Regents, which has governing authority over the state's three public universities, dealt with the inability of the universities to respond to new societal needs in a timely manner; a major impediment was felt to be tenure. After a series of meetings of administrators and faculty leaders, the Board…

  16. Arizona's School Asbestos Program.

    ERIC Educational Resources Information Center

    Charette, Mike L.

    1982-01-01

    The state of Arizona Department of Education operates a successful program to remove asbestos-containing building materials from schools, drawing from the expertise of the Department of Health Services, Bureau of Environmental Hygiene and Sanitation, Bureau of Waste Control, and eliciting cooperation of school officials. Includes an asbestos…

  17. Workforce Brief: Arizona

    ERIC Educational Resources Information Center

    Western Interstate Commission for Higher Education, 2006

    2006-01-01

    In Arizona, one of the country's fastest growing states, the demand for well-educated employees will only increase over the next several years. In the decade leading up to 2013, healthcare occupations will see growth of 50 percent. Almost 1,800 dentists will need to be hired to fill new posts and to cover retirement, for example. Teachers will be…

  18. Indians of Arizona.

    ERIC Educational Resources Information Center

    Bureau of Indian Affairs (Dept. of Interior), Washington, DC.

    Brief descriptions of the historical and cultural background of the Navajo, Apache, Hopi, Pima, Papago, Yuma, Maricopa, Mohave, Cocopah, Havasupai, Hualapai, Yavapai, and Paiute Indian tribes of Arizona are presented. Further information is given concerning the educational, housing, employment, and economic development taking place on the…

  19. Arizona Academic Standards, Kindergarten

    ERIC Educational Resources Information Center

    Arizona Department of Education, 2007

    2007-01-01

    This publication contains Arizona public schools' academic standards for kindergarten. The contents of this document include the following: (1) The Arts Standard 2006--Kindergarten; (2) Comprehensive Health Education/Physical Activity Standards 1997--Readiness (Kindergarten); (3) Foreign and Native Language Standards 1997--Essentials (Grades 4-8);…

  20. Indians of Arizona.

    ERIC Educational Resources Information Center

    Bureau of Indian Affairs (Dept. of Interior), Washington, DC.

    Briefly describing each tribe within Arizona's four major American Indian groups, this handbook presents information relative to the cultural background and socioeconomic development of the following tribes: (1) Athapascan Tribes (Navajos and Apaches); (2) Pueblo Indians (Hopis); (3) Desert Rancheria Tribes (Pimas, Yumas, Papagos, Maricopas,…

  1. Arizona Academic Standards: Kindergarten

    ERIC Educational Resources Information Center

    Arizona Department of Education, 2009

    2009-01-01

    This publication contains Arizona public schools' academic standards for kindergarten. The contents of this document include the following: (1) The Arts Standard 2006--Kindergarten; (2) Comprehensive Health Education/Physical Activity Standards 1997--Readiness (Kindergarten); (3) Foreign and Native Language Standards 1997--Readiness…

  2. Impact Cratering Calculations

    NASA Technical Reports Server (NTRS)

    Ahrens, Thomas J.

    2001-01-01

    We examined the von Mises and Mohr-Coulomb strength models with and without damage effects and developed a model for dilatancy. The models and results are given in O'Keefe et al. We found that by incorporating damage into the models that we could in a single integrated impact calculation, starting with the bolide in the atmosphere produce final crater profiles having the major features found in the field measurements. These features included a central uplift, an inner ring, circular terracing and faulting. This was accomplished with undamaged surface strengths of approximately 0.1 GPa and at depth strengths of approximately 1.0 GPa. We modeled the damage in geologic materials using a phenomenological approach, which coupled the Johnson-Cook damage model with the CTH code geologic strength model. The objective here was not to determine the distribution of fragment sizes, but rather to determine the effect of brecciated and comminuted material on the crater evolution, fault production, ejecta distribution, and final crater morphology.

  3. Fractured Craters on Ganymede

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Two highly fractured craters are visible in this high resolution image of Jupiter's moon, Ganymede. NASA's Galileo spacecraft imaged this region as it passed Ganymede during its second orbit through the Jovian system. North is to the top of the picture and the sun illuminates the surface from the southeast. The two craters in the center of the image lie in the ancient dark terrain of Marius Regio, at 40 degrees latitude and 201 degrees longitude, at the border of a region of bright grooved terrain known as Byblus Sulcus (the eastern portion of which is visible on the left of this image). Pervasive fracturing has occurred in this area that has completely disrupted these craters and destroyed their southern and western walls. Such intense fracturing has occurred over much of Ganymede's surface and has commonly destroyed older features. The image covers an area approximately 26 kilometers (16 miles) by 18 kilometers (11 miles) across at a resolution of 86 meters (287 feet) per picture element. The image was taken on September 6, 1996 by the solid state imaging (CCD) system on NASA's Galileo spacecraft.

    The Jet Propulsion Laboratory, Pasadena, CA manages the Galileo mission for NASA's Office of Space Science, Washington, DC. JPL is an operating division of California Institute of Technology (Caltech).

    This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://galileo.jpl.nasa.gov.

  4. Crater gradation in Gusev crater and Meridiani Planum, Mars

    USGS Publications Warehouse

    Grant, J. A.; Arvidson, R. E.; Crumpler, L.S.; Golombek, M.P.; Hahn, B.; Haldemann, A.F.C.; Li, R.; Soderblom, L.A.; Squyres, S. W.; Wright, S.P.; Watters, W.A.

    2006-01-01

    The Mars Exploration Rovers investigated numerous craters in Gusev crater and Meridiani Planum during the first ???400 sols of their missions. Craters vary in size and preservation state but are mostly due to secondary impacts at Gusev and primary impacts at Meridiani. Craters at both locations are modified primarily by eolian erosion and infilling and lack evidence for modification by aqueous processes. Effects of gradation on crater form are dependent on size, local lithology, slopes, and availability of mobile sediments. At Gusev, impacts into basaltic rubble create shallow craters and ejecta composed of resistant rocks. Ejecta initially experience eolian stripping, which becomes weathering-limited as lags develop on ejecta surfaces and sediments are trapped within craters. Subsequent eolian gradation depends on the slow production of fines by weathering and impacts and is accompanied by minor mass wasting. At Meridiani the sulfate-rich bedrock is more susceptible to eolian erosion, and exposed crater rims, walls, and ejecta are eroded, while lower interiors and low-relief surfaces are increasingly infilled and buried by mostly basaltic sediments. Eolian processes outpace early mass wasting, often produce meters of erosion, and mantle some surfaces. Some small craters were likely completely eroded/buried. Craters >100 m in diameter on the Hesperian-aged floor of Gusev are generally more pristine than on the Amazonian-aged Meridiani plains. This conclusion contradicts interpretations from orbital views, which do not readily distinguish crater gradation state at Meridiani and reveal apparently subdued crater forms at Gusev that may suggest more gradation than has occurred. Copyright 2006 by the American Geophysical Union.

  5. Young Martian crater Gratteri and its secondary craters

    NASA Astrophysics Data System (ADS)

    Quantin, Cathy; Popova, Olga; Hartmann, William K.; Werner, Stephanie C.

    2016-07-01

    In response to questions that have been raised about formation and effects of secondary craters on crater chronometry techniques, we studied properties of the secondary crater field around the young Martian primary ray crater Gratteri (diameter 7 km). The crater has an estimated age of 1 to 20 Myr, based on counts of small craters on flat interior surface, consistent with a likely age for a young crater its size (Hartmann et al., 2010). The following are among our findings: (1) We identify an unusual class of craters we call "rampart secondaries" which may suggest low-angle impacts. (2) We measure size distributions of secondaries as a function of distance from Gratteri and used these data to reconstruct the mass-velocity distribution of ejecta blasted out of Gratteri. Our data suggest that crater density in rays tends to peak around 120-230 km from Gratteri (roughly 20-30D) and reaches roughly 30-70 times the interray crater density. (3) Comparable total numbers of secondaries form inside rays and outside rays, and about half are concentrated in clusters in 2% of the area around Gratteri, with the others scattered over 98% of the area out to 400 km away from Gratteri. (4) In the old Noachian plains around Gratteri, secondaries have minimal effect on crater chronometry. These results, along with recently reported direct measurements of the rate of formation of 10 m to 20 m primaries on Mars (Daubar et al., 2013), tend to negate suggestions that the numbers and/or clustering of secondaries destroy the effectiveness of crater counting as a chronometric tool.

  6. Impacts into Sandstone: Crater Morphology, Crater Scaling and the Effects of Porosity

    NASA Astrophysics Data System (ADS)

    Poelchau, M. H.; Dufresne, A.; Kenkmann, T.

    2011-03-01

    Crater morphology results from impact cratering experiments in sandstone within the MEMIN program are presented and compared to other brittle materials. The effects of porosity on crater shape, volume and cratering efficiency are analyzed.

  7. Depth-to-Diameter Ratio and Slopes in Small Lunar Highland Craters

    NASA Astrophysics Data System (ADS)

    Mahanti, P.; Robinson, M. S.; Stelling, R.

    2012-12-01

    Geomorphology of small lunar highland craters is quantified with digital elevation models (DEM) that cover 540 craters. From these new data we measured apparent depth (Ra), apparent diameter (Da) and wall slopes. While photogrammetric studies exist from Apollo era data [2,3], the lower end of the crater size spectrum is not well represented and the statistics for craters with diameters 150 meters or less is sparse. The slope of log-scale depth-vs.-diameter fit was ~0.9 (Figure 1). Previous studies [3] with both mare and highland craters (Da >330m) had slopes of ~1, so this result was somewhat expected, although the highland data density was poor in this size regime in the earlier works. However, it was found that a straight line represented the depth-vs.-diameter data better than a power law relation (goodness-of-fit 0.97 compared to 0.6) which is interesting since larger craters are found to change shape allometrically [4]. The median value of the depth-to-diameter ratio was ~0.13 which is also unexpected for small craters (usually ~0.2). Wall slopes were relatively shallow (median ~ 8°) with ~95% of the data at slopes less than 18°. Slopes decreased with crater size (Figure 2), with a sharp drop at diameters more than 35m after which the rate of change was small. Decrease in slope with size was observed earlier with Apollo data [2], but for larger craters (Da >1Km). References: [1] Robinson, M.S. et al (2010),Space Sci. Rev.,150,81-124;[2] Pike, R.J.(1977) Proceedings of the Symposium on Planetary Cratering Mechanics, Arizona, Pergamon Press.,489-509;[3] Pike, R.J.(1977) Lunar Science Conference,3, 3427-3436;[4] Pike, R.J(1967) J. Geophys. Res. 72, 8, 2099-2106

  8. What can we learn about impact mechanics from large craters on Venus?

    NASA Technical Reports Server (NTRS)

    Mckinnon, William B.; Alexopoulos, J. S.

    1992-01-01

    More than 50 unequivocal peak-ring craters and multiringed impact basins have been identified on Venus from Earth-based Arecibo, Venera 15/16, and Magellan radar images. These ringed craters are relatively pristine, and so serve as an important new dataset that will further understanding of the structural and rheological properties of the venusian surface and of impact mechanics in general. They are also the most direct analogues for craters formed on the Earth in Phanerozoic time. Finite-element simulations of basin collapse and ring formation were undertaken in collaboration with V. J. Hillgren (University of Arizona). These calculations used an axisymmetric version of the viscoelastic finite element code TECTON, modeled structures on the scale of Klenova or Meitner, and demonstrated two major points. First, viscous flow and ring formation are possible on the timescale of crater collapse for the sizes of multiringed basins seen on Venus and heat flows appropriate to the plant. Second, an elastic lithosphere overlying a Newtonian viscous asthenosphere results mainly in uplift beneath the crater. Inward asthenospheric flow mainly occurs at deeper levels. Lithospheric response is dominantly vertical and flexural. Tensional stress maxima occur and ring formation by normal faulting is predicted in some cases, but these predicted rings occur too far out to explain observed ring spacings on Venus (or on the Moon). Overall, these estimates and models suggest that multiringed basin formation is indeed possible at the scales observed on Venus. Furthermore, due to the strong inverse dependence of solid-state viscosity on stress, the absence of Cordilleran-style ring faulting in craters smaller than Meitner or Klenova makes sense. The apparent increase in viscosity of shock-fluidized rock with crater diameter, greater interior temperatures accessed by larger, deeper craters, and decreased non-Newtonian viscosity associated with larger craters may conspire to make the

  9. Solar influence on meteor rates and atmospheric density variations at meteor heights

    NASA Technical Reports Server (NTRS)

    Ellyett, C.

    1977-01-01

    Lindblad (1967) has concluded that there was an inverse relation between meteor rates and the solar cycle brought about by an increase in atmospheric density gradient at the height of meteor ionization. The present paper investigates Lindblad's conclusion more fully by using three long series of continuous radar meteor data from New Zealand and Canada. The results confirm a clear variation of total rate from year to year, inversely correlated with the annual sunspot number. Although meteor rates call for a density gradient variation inversely related to the solar cycle, direct evidence for such a variation remains nonexistant. Possibly the effect is being obscured by other density changes occurring at these heights. Analysis of meteor rates within the same one-year period in the two hemispheres has established that seasonal rate changes brought about by the variation of the angle between the latitude of the observing station and the apex of the earth's way override change of density gradient in at least one of the hemispheres and possibly both in controlling meteor rates within the year.

  10. Degradation studies of Martian impact craters

    NASA Technical Reports Server (NTRS)

    Barlow, N. G.

    1991-01-01

    The amount of obliteration suffered by Martian impact craters is quantified by comparing measurable attributes of the current crater shape to those values expected for a fresh crater of identical size. Crater diameters are measured from profiles obtained using photoclinometry across the structure. The relationship between the diameter of a fresh crater and a crater depth, floor width, rim height, central peak height, etc. was determined by empirical studies performed on fresh Martian impact craters. We utilized the changes in crater depth and rim height to judge the degree of obliteration suffered by Martian impact craters.

  11. Mannann'an Crater

    NASA Technical Reports Server (NTRS)

    1998-01-01

    This composite view taken by NASA's Galileo spacecraft shows the rim and interior of the impact crater, Mannann'an, on Jupiter's moon, Europa. A high resolution image (20 meters per picture element) was combined with lower resolution (80 meters per picture element) color images taken through violet, green and near-infrared filters, to produce this synthetic color composite image. The color data can be used to distinguish between regions of purer (clean) and more contaminated (dirty) ice on the surface, and also offers information on the size of the ice grains. The reddish brown material is thought to be dirty ice, while the bluish areas inside the crater are purer ice. The crater rim is on the left at the boundary between the reddish brown material and the gray material.

    The high resolution data show small features inside the crater, including concentric fractures and a spider-like set of fractures near the right (east) edge of the image. For a more regional perspective, the Mannann'an crater can be seen as a large circular feature with bright rays in the lower left corner of a regional image from Galileo's first orbit of Jupiter in June 1996.

    North is to the top of the picture and the Sun illuminates the scene from the east (right). The image, centered at 3 degrees north latitude and 240 degrees west longitude, covers an area approximately 18 by 4 kilometers (11 by 2.5 miles). The finest details that can be discerned in this picture are about 40 meters (44 yards) across. The images were taken by the spacecraft's onboard solid state imaging camera when Galileo flew by Europa on March 29th, 1998 at a distance of 1,934 kilometers (1,200 miles).

    The Jet Propulsion Laboratory, Pasadena, CA manages the Galileo mission for NASA's Office of Space Science, Washington, DC. JPL is an operating division of California Institute of Technology (Caltech).

    This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo

  12. Video Observations of Meteors: History, Current Status, and Future Prospects

    NASA Astrophysics Data System (ADS)

    Molau, S.; Nitschke, M.; de Lignie, M.; Hawkes, R. L.; Rendtel, J.

    1997-02-01

    Video meteor observations have been performed by amateur astronomers for more than 10 years. They enjoy a rapidly increasing interest in the meteor community and will evolve into a powerful tool for amateur observers in the near future. Video meteor observation is the key to a fundamental increase of our knowledge about meteoroid populations and their interaction with the Earth's atmosphere. In this paper, we want to summarize the history of video meteor observation and describe the current state of affairs. We discuss problems and limitations and propose future projects. The paper is intended to serve as basis for the foundation of appropriate organizational structures within the International Meteor Organization.

  13. Spectral analysis of four meteors. [chemical compositions and spectral emissions

    NASA Technical Reports Server (NTRS)

    Harvey, G. A.

    1973-01-01

    Four meteor spectra are analyzed for chemical composition and radiative processes. The chemical compositions of the Taurid, Geminid, and Perseid meteors were found to be similar to that of a typical stony meteorite. The chemical composition of the sporadic meteor was found to be similar to that of a nickel iron meteorite. The radiation from optical meteors was found to be similar to that of a low temperature gas, except that strong, anomalous ionic radiation is superposed on the neutral radiation in bright, fast meteors.

  14. Oblique View of Eros' Crater

    NASA Technical Reports Server (NTRS)

    2000-01-01

    This image, showing an oblique view of Eros' large central crater, was taken at a resolution of about 20 meters (65 feet) per pixel. The brightness or albedo patterns on the walls of this crater are clearly visible, with the brighter materials near the tops of the walls and darker materials on the lower walls. Boulders are seen inside this crater and the smaller nearby craters. The higher density of craters to the left of the large crater implies that this region is older than the smoother area seen associated with the saddle region on the opposite side of the asteroid.

    Built and managed by The Johns Hopkins University Applied Physics Laboratory, Laurel, Maryland, NEAR was the first spacecraft launched in NASA's Discovery Program of low-cost, small-scale planetary missions. See the NEAR web page at http://near.jhuapl.edu for more details.

  15. The Martian impact cratering record

    NASA Technical Reports Server (NTRS)

    Strom, Robert G.; Croft, Steven K.; Barlow, Nadine G.

    1992-01-01

    A detailed analysis of the Martian impact cratering record is presented. The major differences in impact crater morphology and morphometry between Mars and the moon and Mercury are argued to be largely the result of subsurface volatiles on Mars. In general, the depth to these volatiles may decrease with increasing latitude in the southern hemisphere, but the base of this layer may be at a more or less constant depth. The Martial crustal dichotomy could have been the result of a very large impact near the end of the accretion of Mars. Monte Carlo computer simulations suggest that such an impact was not only possible, but likely. The Martian highland cratering record shows a marked paucity of craters less than about 30 km in diameter relative to the lunar highlands. This paucity of craters was probably the result of the obliteration of craters by an early period of intense erosion and deposition by aeolian, fluvial, and glacial processes.

  16. Crater Count Ages of Young Martian Ray Craters: a Successful Test of the Crater Chronometry System

    NASA Astrophysics Data System (ADS)

    Hartmann, William K.; Quantin, C.; Werner, S. C.; Popova, O.

    2008-09-01

    McEwen et al. (2005) developed a useful test of crater-count chronometry systems [1]. They argued that fresh-looking, Zunil-style Martian ray craters are the youngest or near-youngest craters in their size ranges. The "McEwen et al. test" is that crater-count ages from small craters (D 10-25 m), superimposed on these "Zunils," should be comparable to the expected formation intervals of these host Zunil-style primaries themselves, typically 1 to a few My. McEwen et al., however, found few or no small superposed craters in MOC frames, and concluded that crater chronometry systems are in error by factors of 700 to 2000. Since then, Malin et al. discovered that 10-25m craters form at essentially the rate we used in our isochron system [2,3,4]. Thus, 10-25m craters should be usable for dating these "Zunils." We re-evaluate the "McEwen et al. test" with HiRise images, studying three young craters they discussed, and five others. In every case we found small-crater populations, giving approximately the expected ages. We conclude that the alleged large errors are incorrect. The semi-independent crater count systems of Neukum and of Hartmann agree with the Malin cratering rate, are internally consistent, and appear to give valid age information within about a factor 2 to 4. We thank the International Space Science Institute (ISSI), Bern, for hosting our working group. [1] McEwen et al. 2005 Icarus,176, 351-381. [2] Malin, M. et al. 2006 Science 314, 1573-1557. [3] Hartmann, W.K. 2007 Icarus, 189, 274-278. [4] Kreslavsky, M.A. 2007 7th Internatl. Conf. on Mars, Abstract 3325.

  17. 'Victoria Crater' from 'Duck Bay'

    NASA Technical Reports Server (NTRS)

    2006-01-01

    NASA's Mars rover Opportunity edged 3.7 meters (12 feet) closer to the top of the 'Duck Bay' alcove along the rim of 'Victoria Crater' during the rover's 952nd Martian day, or sol (overnight Sept. 27 to Sept. 28), and gained this vista of the crater. The rover's navigation camera took the seven exposures combined into this mosaic view of the crater's interior. This crater has been the mission's long-term destination for the past 21 Earth months.

    The far side of the crater is about 800 meters (one-half mile) away. The rim of the crater is composed of alternating promontories, rocky points towering approximately 70 meters (230 feet) above the crater floor, and recessed alcoves, such as Duck Bay. The bottom of the crater is covered by sand that has been shaped into ripples by the Martian wind. The rocky cliffs in the foreground have been informally named 'Cape Verde,' on the left, and 'Cabo Frio,' on the right.

    Victoria Crater is about five times wider than 'Endurance Crater,' which Opportunity spent six months examining in 2004, and about 40 times wider than 'Eagle Crater,' where Opportunity first landed. The great lure of Victoria is an expectation that the thick stack of geological layers exposed in the crater walls could reveal the record of past environmental conditions over a much greater span of time than Opportunity has read from rocks examined earlier in the mission.

    This view is presented as a cylindrical projection with geometric seam correction.

  18. The Virtual Arizona Experience

    NASA Astrophysics Data System (ADS)

    Allison, M. L.; Davis, R.; Conway, F. M.; Bellasai, R.

    2012-12-01

    To commemorate the once-in-a-lifetime event of Arizona's hundredth birthday, the Centennial Commission and the Governor of Arizona envisioned a museum and companion website that would capture the state's history, celebrate its people, and embrace its future. Working with world-renowned museum designers, the state began to seek ideas from across Arizona to create plans for a journey of discovery through science and the humanities. The museum would introduce visitors to some of the people who nurtured the state through its early years and others who are innovating its tomorrows. Showcases would include the resources and experiences that shaped the state's history and are transforming its present day, highlighting the ingenuity that tamed the wild frontier and is envisioning Arizona's next frontiers through science and technology. The Arizona Experience (www.arizonaexperience.org) was initially intended to serve as the web presence for the physical museum, but as delays occurred with the physical museum, the site has quickly developed an identify of its own as an interactive, multimedia experience, reaching a wider audience with functions that would be difficult or expensive to produce in a museum. As leaders in scientific and technological innovation in the state, the Arizona Geological Survey was tasked with designing and creating the Arizona Experience site. The general themes remain the same; however, the site has added content and applications that are better suited to the online environment in order to create a rich, dynamic supplement to a physical museum experience. The website offers the features and displays of the future museum with the interactive nature and learning environment of the web. This provides an encyclopedic overview of the State of Arizona by subject matter experts in a manner that is free and open to the public and erases socio-economic, political, and physical boundaries. Over the Centennial Year of 2012 the site will release a new theme and

  19. Identification of craters on Moon using Crater Density Parameter

    NASA Astrophysics Data System (ADS)

    Vandana, Vandana

    2016-07-01

    Lunar craters are the most noticeable features on the face of the moon. They take up 40.96% of the lunar surface and, their accumulated area is approximately three times as much as the lunar surface area. There are many myths about the moon. Some says moon is made of cheese. The moon and the sun chase each other across the sky etc. but scientifically the moon are closest and are only natural satellite of earth. The orbit plane of the moon is tilted by 5° and orbit period around the earth is 27-3 days. There are two eclipse i.e. lunar eclipse and solar eclipse which always comes in pair. Moon surface has 3 parts i.e. highland, Maria, and crater. For crater diagnostic crater density parameter is one of the means for measuring distance can be easily identity the density between two craters. Crater size frequency distribution (CSFD) is being computed for lunar surface using TMC and MiniSAR image data and hence, also the age for the selected test sites of mars is also determined. The GIS-based program uses the density and orientation of individual craters within LCCs (as vector points) to identify potential source craters through a series of cluster identification and ejection modeling analyses. JMars software is also recommended and operated only the time when connected with server but work can be done in Arc GIS with the help of Arc Objects and Model Builder. The study plays a vital role to determine the lunar surface based on crater (shape, size and density) and exploring affected craters on the basis of height, weight and velocity. Keywords: Moon; Crater; MiniSAR.

  20. Cratered terrain in Terra Meridiani

    NASA Technical Reports Server (NTRS)

    2002-01-01

    (Released 30 April 2002) The Science This THEMIS visible image shows a region in Terra Meridiani near -12o S, 358o W (2o E). An old, heavily degraded channel can be seen from the lower (southern) portion of the image toward the top. This channel appears to terminate abruptly at the rim of a 10 km diameter crater. This apparent 'superposition' of the crater on top of the channel suggests that the impact crater was created after the channel was formed. This crater has two 3-km sized blocks of material that have slumped off from the lower left segment of the original crater rim. These immense blocks must have moved as a single unit because the rock layers that can be seen in the original wall of the crater can still be seen in these detached blocks. The walls of several craters in this image show vague hints of possible gully formation at the bottom of pronounced rock layers, with the suggestion of alcoves above the individual gullies. Well-developed gullies that were imaged by the Mars Orbiter Camera (MOC) on Mars Global Surveyor have been suggested to form by seepage and runoff of a fluid. The MOC has observed these gullies in numerous craters and channels further south, but they are uncommon at latitudes this close to the equator. Several sections of the crater walls appear to have ridges and troughs formed by the dry avalanche of loose rock, and a similar process of dry avalanche may account for the gullies seen in this THEMIS image. Patches of lighter material, possibly small dunes ripples, can be seen in several places throughout this image. The Story When the walls come tumbling down! Take a closer look at the bright linear ridges within a deep crater near the center of this image (bottom, left-hand side of the crater). Almost 2 miles long, these chunks of material slumped off the crater side in one fell swoop. Phoozhj! Down they came as one massive unit. You can tell, because the rock layers seen in the original wall of the crater are also still there in the

  1. Why do complex impact craters have elevated crater rims?

    NASA Astrophysics Data System (ADS)

    Kenkmann, Thomas; Sturm, Sebastian; Krueger, Tim

    2014-05-01

    Most of the complex impact craters on the Moon and on Mars have elevated crater rims like their simple counterparts. The raised rim of simple craters is the result of (i) the deposition of a coherent proximal ejecta blanket at the edge of the transient cavity (overturned flap) and (ii) a structural uplift of the pre-impact surface near the transient cavity rim during the excavation stage of cratering [1]. The latter occurs either by plastic thickening or localized buckling of target rocks, as well as by the emplacement of interthrust wedges [2] or by the injection of dike material. Ejecta and the structural uplift contribute equally to the total elevation of simple crater rims. The cause of elevated crater rims of large complex craters [3] is less obvious, but still, the rim height scales with the final crater diameter. Depending on crater size, gravity, and target rheology, the final crater rim of complex craters can be situated up to 1.5-2.0 transient crater radii distance from the crater center. Here the thickness of the ejecta blanket is only a fraction of that occurring at the rim of simple craters, e.g. [4], and thus cannot account for a strong elevation. Likewise, plastic thickening including dike injection of the underlying target may not play a significant role at this distance any more. We started to systematically investigate the structural uplift and ejecta thickness along the rim of complex impact craters to understand the cause of their elevation. Our studies of two lunar craters (Bessel, 16 km diameter and Euler, 28 km diameter) [5] and one unnamed complex martian crater (16 km diameter) [6] showed that the structural uplift at the final crater rim makes 56-67% of the total rim elevation while the ejecta thickness contributes 33-44%. Thus with increasing distance from the transient cavity rim, the structural uplift seems to dominate. As dike injection and plastic thickening are unlikely at such a distance from the transient cavity, we propose that

  2. Crater Highlands, Tanzania

    NASA Technical Reports Server (NTRS)

    2006-01-01

    The Shuttle Radar Topography Mission (SRTM), flown aboard Space Shuttle Endeavour in February 2000, acquired elevation measurements for nearly all of Earth's landmass between 60oN and 56oS latitudes. For many areas of the world SRTM data provide the first detailed three-dimensional observation of landforms at regional scales. SRTM data were used to generate this view of the Crater Highlands along the East African Rift in Tanzania. Landforms are depicted with colored height and shaded relief, using a vertical exaggeration of 2X and a southwestwardly look direction.

    Lake Eyasi is depicted in blue at the top of the image, and a smaller lake occurs in Ngorongoro Crater. Near the image center, elevations peak at 3648 meters (11,968 feet) at Mount Loolmalasin, which is south of Ela Naibori Crater. Kitumbeine (left) and Gelai (right) are the two broad mountains rising from the rift lowlands. Mount Longido is seen in the lower left, and the Meto Hills are in the right foreground.

    Tectonics, volcanism, landslides, erosion and deposition -- and their interactions -- are all very evident in this view. The East African Rift is a zone of spreading between the African (on the west) and Somali (on the east) crustal plates. Two branches of the rift intersect here in Tanzania, resulting in distinctive and prominent landforms. One branch trends nearly parallel the view and includes Lake Eyasi and the very wide Ngorongoro Crater. The other branch is well defined by the lowlands that trend left-right across the image (below center, in green). Volcanoes are often associated with spreading zones where magma, rising to fill the gaps, reaches the surface and builds cones. Craters form if a volcano explodes or collapses. Later spreading can fracture the volcanoes, which is especially evident on Kitumbeine and Gelai Mountains (left and right, respectively, lower center).

    The Crater Highlands rise far above the adjacent savannas, capture moisture from passing air masses

  3. Interferometric Meteor Head Echo Observations using the Southern Argentina Agile Meteor Radar (SAAMER)

    NASA Technical Reports Server (NTRS)

    Janches, D.; Hocking, W.; Pifko, S.; Hormaechea, J. L.; Fritts, D. C.; Brunini, C; Michell, R.; Samara, M.

    2013-01-01

    A radar meteor echo is the radar scattering signature from the free-electrons in a plasma trail generated by entry of extraterrestrial particles into the atmosphere. Three categories of scattering mechanisms exist: specular, nonspecular trails, and head-echoes. Generally, there are two types of radars utilized to detect meteors. Traditional VHF meteor radars (often called all-sky1radars) primarily detect the specular reflection of meteor trails traveling perpendicular to the line of sight of the scattering trail, while High Power and Large Aperture (HPLA) radars efficiently detect meteor head-echoes and, in some cases, non-specular trails. The fact that head-echo measurements can be performed only with HPLA radars limits these studies in several ways. HPLA radars are very sensitive instruments constraining the studies to the lower masses, and these observations cannot be performed continuously because they take place at national observatories with limited allocated observing time. These drawbacks can be addressed by developing head echo observing techniques with modified all-sky meteor radars. In addition, the fact that the simultaneous detection of all different scattering mechanisms can be made with the same instrument, rather than requiring assorted different classes of radars, can help clarify observed differences between the different methodologies. In this study, we demonstrate that such concurrent observations are now possible, enabled by the enhanced design of the Southern Argentina Agile Meteor Radar (SAAMER) deployed at the Estacion Astronomica Rio Grande (EARG) in Tierra del Fuego, Argentina. The results presented here are derived from observations performed over a period of 12 days in August 2011, and include meteoroid dynamical parameter distributions, radiants and estimated masses. Overall, the SAAMER's head echo detections appear to be produced by larger particles than those which have been studied thus far using this technique.

  4. Martian Cratering 4: Mariner 9 Initial Analysis of Cratering Chronology

    NASA Technical Reports Server (NTRS)

    Hartmann, W. K.

    1973-01-01

    Early analyses of cratering and other Martian surface properties that indicated extensive ancient erosion have been strongly supported by Mariner 9 data. By their great variations in density, these craters indicate a history of Martian erosion and crustal development intermediate between earth and the moon.

  5. Becquerel Crater Deposit

    NASA Technical Reports Server (NTRS)

    2002-01-01

    (Released 28 May 2002) The finely layered deposit in Becquerel crater, seen in the center of this THEMIS image, is slowly being eroded away by the action of windblown sand. Dark sand from a source north of the bright deposit is collecting along its northern edge, forming impressive barchan style dunes. These vaguely boomerang-shaped dunes form with their two points extending in the downwind direction, demonstrating that the winds capable of moving sand grains come from the north. Grains that leave the dunes climb the eroding stair-stepped layers, collecting along the cliff faces before reaching the crest of the deposit. Once there, the sand grains are unimpeded and continue down the south side of the deposit without any significant accumulation until they fall off the steep cliffs of the southern margin. The boat-hull shaped mounds and ridges of bright material called yardangs form in response to the scouring action of the migrating sand. To the west, the deposit has thinned enough that the barchan dunes extend well into the deeply eroded north-south trending canyons. Sand that reaches the south side collects and reforms barchan dunes with the same orientation as those on the north side of the deposit. Note the abrupt transition between the bright material and the dark crater floor on the southern margin. Steep cliffs are present with no indication of rubble from the obvious erosion that produced them. The lack of debris at the base of the cliffs is evidence that the bright material is readily broken up into particles that can be transported away by the wind. The geological processes that are destroying the Becquerel crater deposit appear active today. But it is also possible that they are dormant, awaiting a particular set of climatic conditions that produces the right winds and perhaps even temperatures to allow the erosion to continue.

  6. Impactites from Popigai Crater

    NASA Technical Reports Server (NTRS)

    Masaitis, V. L.

    1992-01-01

    Impactites (tagamites and suevites) from Popigai impact crater, whose diameter is about 100 km, are distributed over an area of 5000 sq km. The continuous sheet of suevite overlies the allogenic polymict breccia and partly authogenic breccia, and may also be observed in lenses or irregular bodies. The thickness of suevites in the central part of the crater is more than 100 m. Suevites may be distinguished by content of vitroclasts, lithoclasts, and crystalloclasts, by their dimensions, and by type of cementation, which reflects the facial settings of ejection of crushed and molten material, its sedimentation and lithification. Tagamites (impact melt rocks) are distributed on the surface predominantly in the western sector of the crater. The most characteristic are thick sheetlike bodies overlying the allogenic breccia and occurring in suevites where minor irregular bodies are widespread. The maximal thickness of separate tagamite sheets is up to 600 m. Tagamites, whose matrix is crystallized to a different degree, include fragments of minerals and gneiss blocks, among them shocked and thermally metamorphosed ones. Tagamite sheets have a complex inner structure; separate horizontal zones distinguish in crystallinity and fragment saturation. Differentiation in the impact melt in situ was not observed. The average chemical compositions of tagamites and suevites are similar, and correspond to the composition of biotite-garnet gneisses of the basement. According to the content of supplied Ir, Ni, and other siderophiles, impact melt was contaminated by 5 percent cosmic matter of collided body, probably ordinary chondrite. The total volume of remaining products of chilled impact melt is about 1750 cu km. Half this amount is represented by tagamite bodies. Though impact melt was in general well homogenized, the trend analysis showed that the concentric zonation is distribution of SiO2, MgO, and Na2O and the bandlike distribution of FeO and Al2O3 content testifies to a

  7. Gullies in Crater Wall

    NASA Technical Reports Server (NTRS)

    2004-01-01

    6 April 2004 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows gullies in the wall of a large impact crater in Newton Basin near 41.9oS, 158.1oW. Such gullies may have formed by downslope movement of wet debris--i.e., water. Unfortunately, because the responsible fluid (if there was one) is no longer present today, only the geomorphology of the channels and debris aprons can be used to deduce that water might have been involved. The image covers an area about 3 km (1.9 mi) across. Sunlight illuminates the scene from the upper left.

  8. Crater Down Below-3

    NASA Technical Reports Server (NTRS)

    2004-01-01

    Scientists believe the circular feature in this image to be a crater near the Mars Exploration Rover Opportunity. The rover landed at Meridiani Planum on Mars at approximately 9:05 p.m. PST on Saturday, Jan. 24. This image was taken at an altitude of 1,404 meters (4,606 feet) by the descent image motion estimation system camera located on the bottom of the rover. The image spans approximately 1.2 kilometers (3/4 of a mile) across the surface of Mars.

  9. Crater Down Below

    NASA Technical Reports Server (NTRS)

    2004-01-01

    Scientists believe the circular feature in this image to be a crater near the Mars Exploration Rover Opportunity. The rover landed at Meridiani Planum on Mars at approximately 9:05 p.m. PST on Saturday, Jan. 24. This image was taken at an altitude of 1,986 meters (6,516 feet) by the descent image motion estimation system camera located on the bottom of the rover. The image spans approximately 1.6 kilometers (1 mile) across the surface of Mars.

  10. Crater Down Below-2

    NASA Technical Reports Server (NTRS)

    2004-01-01

    Scientists believe the circular feature in this image to be a crater near the Mars Exploration Rover Opportunity. The rover landed at Meridiani Planum on Mars at approximately 9:05 p.m. PST on Saturday, Jan. 24. This image was taken at an altitude of 1,690 meters (5,545 feet) by the descent image motion estimation system camera located on the bottom of the rover. The image spans approximately 1.4 kilometers (7/8 of a mile) across the surface of Mars.

  11. PUSCH RIDGE WILDERNESS, ARIZONA.

    USGS Publications Warehouse

    Hinkle, Margaret E.; Ryan, George S.

    1984-01-01

    On the basis of a mineral survey, the Pusch Ridge Wilderness, located at the northern boundary of the city of Tucson, Arizona, offers little or no promise for the occurrence of energy resources. Only one area contains a probable potential for small, isolated contact-metamorphic deposits containing copper, molybdenum, tungsten, lead, and zinc. This area is located around the southwestern end of Pusch Ridge, adjacent to a residential area.

  12. RATTLESNAKE ROADLESS AREA, ARIZONA.

    USGS Publications Warehouse

    Karlstrom, Thor N.V.; McColly, Robert

    1984-01-01

    There is little promise for the occurrence of mineral or energy resources in the Rattlesnake Roadless Area, Arizona, as judged from field studies. Significant concentrations of minerals within the roadless area are not indicated by geologic mapping, geochemical sampling, or aeromagnetic studies. Basalt, volcanic cinders, sand and gravel, and sandstone that may be suitable for construction materials occur in the area, but are more readily accessible outside the roadless area boundary.

  13. Dune-filled Crater in Color

    NASA Technical Reports Server (NTRS)

    2004-01-01

    [figure removed for brevity, see original site]

    Released 4 May 2004 This daytime visible color image was collected on October 16, 2003 during the Southern Summer season of a crater within Molesworth Crater.

    This daytime visible color image was collected on September 4, 2002 during the Northern Spring season in Vastitas Borealis. The THEMIS VIS camera is capable of capturing color images of the martian surface using its five different color filters. In this mode of operation, the spatial resolution and coverage of the image must be reduced to accommodate the additional data volume produced from the use of multiple filters. To make a color image, three of the five filter images (each in grayscale) are selected. Each is contrast enhanced and then converted to a red, green, or blue intensity image. These three images are then combined to produce a full color, single image. Because the THEMIS color filters don't span the full range of colors seen by the human eye, a color THEMIS image does not represent true color. Also, because each single-filter image is contrast enhanced before inclusion in the three-color image, the apparent color variation of the scene is exaggerated. Nevertheless, the color variation that does appear is representative of some change in color, however subtle, in the actual scene. Note that the long edges of THEMIS color images typically contain color artifacts that do not represent surface variation.

    Image information: VIS instrument. Latitude -27.4, Longitude 149.6 East (210.4 West). 19 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in

  14. The cometary and asteroidal origins of meteors

    NASA Technical Reports Server (NTRS)

    Kresak, L.

    1973-01-01

    A quantitative examination of the gravitational and nongravitational changes of orbits shows that for larger interplanetary bodies the perturbations by Jupiter strongly predominate over all other effects, which include perturbations by other planets, splitting of comet nuclei and jet effects of cometary ejections. The structure of meteor streams, indicates that the mutual compensation of the changes in individual elements entering the Jacobian integral, which is characteristic for the comets, does not work among the meteoroids. It appears that additional forces of a different kind must exert appreciable influence on the motion of interplanetary particles of meteoroid size. Nevertheless, the distribution of the Jacobian constant in various samples of meteor orbits furnishes some information on the type of their parent bodies and on the relative contribution of individual sources.

  15. Meteor detection on ST (MST) radars

    NASA Technical Reports Server (NTRS)

    Avery, S. K.

    1987-01-01

    The ability to detect radar echoes from backscatter due to turbulent irregularities of the radio refractive index in the clear atmosphere has lead to an increasing number of established mesosphere - stratosphere - troposphere (MST or ST) radars. Humidity and temperature variations are responsible for the echo in the troposphere and stratosphere and turbulence acting on electron density gradients provides the echo in the mesosphere. The MST radar and its smaller version, the ST radar, are pulsed Doppler radars operating in the VHF - UHF frequency range. These echoes can be used to determine upper atmosphere winds at little extra cost to the ST radar configuration. In addition, the meteor echoes can supplement mesospheric data from an MST radar. The detection techniques required on the ST radar for delineating meteor echo returns are described.

  16. Data processing of records of meteoric echoes

    NASA Astrophysics Data System (ADS)

    Dolinský, P.

    2016-01-01

    The data obtained in the period from 4 November 2014 to 31 July 2014 by our receiving and recording system was statistically processed. The system records meteoric echoes from the TV transmitter Lviv 49.739583 MHz (N49.8480° E24.0369°, Ukraine) using a 4-element Yagi antenna with horizontal polarization (elevation of 0° and azimuth of 60°), receiver ICOM R-75 in the CW mode, and a computer with a recording using HROFFT v1.0.0f. The main goal was to identify weak showers in these data. Mayor or strong showers are visible without processing (referred at IMC2015, Mistelbach). To find or to identify weaker showers is more difficult. Not all echoes are meteoric echoes, but also ionospheric echoes or lightning disturbances are present.

  17. The Swedish Allsky Meteor Network: first results

    NASA Astrophysics Data System (ADS)

    Stempels, E.; Kero, E.

    2016-01-01

    The Swedish Allsky Meteor Network started operations with two cameras in early 2014 and has since grown steadily. Currently, seven stations are active and several more will come online in the near future. The network to a large degree relies on low-cost stations run by private individuals or small societies of amateur astronomers. Originally based on the Danish meteor network Stjerneskud, the central node of Uppsala University provides the network with the necessary infrastructure, such as a continually updated software distribution and automatic processing of data from all stations. Although covering a very large land mass with relatively low resources is challenging, there have up to now been several well-observed events, often in collaboration with observations from neighboring countries. We give a short overview of the network's current status, chosen technical solutions, and some results.

  18. Structural peculiarities of the Quadrantid meteor shower

    NASA Technical Reports Server (NTRS)

    Isamutdinov, Sh. O.; Chebotarev, R. P.

    1987-01-01

    Systematic radio observations to investigate the Quadrantid meteor shower structure are regularly carried out. They have now been conducted annually in the period of its maximum activity, January 1 to 6, since 1966. The latest results of these investigations are presented, on the basis of 1981 to 1984 data obtained using new equipment with a limiting sensitivity of +7.7 sup m which make it possible to draw some conclusions on the Quadrantids shower structure both for transverse and lengthwise directions.

  19. Recent meteor showers - models and observations

    NASA Astrophysics Data System (ADS)

    Koten, P.; Vaubaillon, J.

    2015-10-01

    A number of meteor shower outbursts and storms occurred in recent years starting with several Leonid storms around 2000 [1]. The methods of modeling meteoroid streams became better and more precise. An increasing number of observing systems enabled better coverage of such events. The observers provide modelers with an important feedback on precision of their models. Here we present comparison of several observational results with the model predictions.

  20. A Global Atmospheric Model of Meteoric Iron

    NASA Technical Reports Server (NTRS)

    Feng, Wuhu; Marsh, Daniel R.; Chipperfield, Martyn P.; Janches, Diego; Hoffner, Josef; Yi, Fan; Plane, John M. C.

    2013-01-01

    The first global model of meteoric iron in the atmosphere (WACCM-Fe) has been developed by combining three components: the Whole Atmosphere Community Climate Model (WACCM), a description of the neutral and ion-molecule chemistry of iron in the mesosphere and lower thermosphere (MLT), and a treatment of the injection of meteoric constituents into the atmosphere. The iron chemistry treats seven neutral and four ionized iron containing species with 30 neutral and ion-molecule reactions. The meteoric input function (MIF), which describes the injection of Fe as a function of height, latitude, and day, is precalculated from an astronomical model coupled to a chemical meteoric ablation model (CABMOD). This newly developed WACCM-Fe model has been evaluated against a number of available ground-based lidar observations and performs well in simulating the mesospheric atomic Fe layer. The model reproduces the strong positive correlation of temperature and Fe density around the Fe layer peak and the large anticorrelation around 100 km. The diurnal tide has a significant effect in the middle of the layer, and the model also captures well the observed seasonal variations. However, the model overestimates the peak Fe+ concentration compared with the limited rocket-borne mass spectrometer data available, although good agreement on the ion layer underside can be obtained by adjusting the rate coefficients for dissociative recombination of Fe-molecular ions with electrons. Sensitivity experiments with the same chemistry in a 1-D model are used to highlight significant remaining uncertainties in reaction rate coefficients, and to explore the dependence of the total Fe abundance on the MIF and rate of vertical transport.

  1. Automatic Crater Counts on Mars

    NASA Astrophysics Data System (ADS)

    Plesko, C.; Brumby, S.; Asphaug, E.; Chamberlain, D.; Engel, T.

    2004-03-01

    We present results of an automated crater counting technique for THEMIS data. Algorithms were developed using GENIE machine learning software. The technique detects craters, generalizes well to new data, and is used to rapidly produce R-plots and statistical data.

  2. Exploration Zone in Newton Crater

    NASA Astrophysics Data System (ADS)

    Laine, P. E.

    2015-10-01

    Newton is a large crater (300 km) located in Terra Sirenum. This region is heavily cratered, preserves crustal magnetism, and has ground ice present. Within this EZ there are many potential science and resource ROIs, e.g. indicatives of past water.

  3. The terrestrial impact cratering record.

    NASA Astrophysics Data System (ADS)

    Grieve, R. A. F.; Pesonen, L. J.

    1992-12-01

    Approximately 130 terrestrial hypervelocity impact craters are currently known. The rate of discovery of new craters is 3 - 5 craters per year. Although modified by erosion, terrestrial impact craters exhibit the range of morphologies observed for craters on other terrestrial planetary bodies. Due to erosion and its effects on form, terrestrial craters are recognized primarily by the occurrence of shock metamorphic effects. Terrestrial craters have a set of geophysical characteristics which are largely the result of the passage of a shock wave and impact-induced fracturing. Much current work is focused on the effects of impact on Earth evolution. Previous work on shock metamorphism and the contamination of impact melt rocks by meteoritic siderophile elements provides a basis for the interpretation of the physical and chemical evidence from Cretaceous-Tertiary boundary sites as resulting from a major impact. By analogy with the lunar record and modelling of the effects of very large impacts, it has been proposed that biological and atmospheric evolution of the Earth could not stabilize before the end of the late heavy bombardment ≡3.8 Ga ago. The present terrestrial cratering rate is 5.4±2.7×10-15 km-2a-1 for a diameter ≥20 km. On a gobal scale, a major impact sufficient to cripple human civilization severely will occur on time scales of ≡106a.

  4. An FDTD model of scattering from meteor head plasma

    NASA Astrophysics Data System (ADS)

    Marshall, R. A.; Close, S.

    2015-07-01

    We have developed a three-dimensional finite difference time domain (FDTD) model of scattering of radar waves from meteor head plasma. The model treats the meteor head plasma as a cold, collisional, and magnetized plasma, and solves Maxwell's equations and the Langevin equation simultaneously and self-consistently in and around the plasma. We use this model to investigate scattering of radar waves from a meteor head (the "head echo") under a range of plasma densities, meteor scale sizes, and wave frequencies. In this way we relate the radar cross section (RCS) to these variable parameters. We find that computed RCS disagrees with previous analytical theory at certain meteor sizes and densities, in some cases by over an order of magnitude. We find that the calculated meteor head RCS is monotonically related to the "overdense area" of the meteor, defined as the cross-section area of the part of the meteor where the plasma frequency exceeds the wave frequency. These results provides a physical measure of the meteor size and density that can be inferred from measured RCS values from ground-based radars. Meteoroid mass can then be inferred from the meteor plasma distribution using established methods.

  5. Secondary Craters on Ganymede

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Two large, ancient impact craters, known as palimpsests, have modified this area of dark terrain on Jupiter's moon Ganymede. In lower resolution images from the Voyager mission in 1979, it was observed that the diffuse edge of a large, circular bright feature cut through this area. This image was obtained by the Solid State Imaging (CCD) system aboard NASA's Galileo spacecraft, on September 6, 1996, at a higher resolution of 190 meters (623 feet) per picture element (pixel). North is to the top. The diffuse margin of this palimpsest is noticeable only as a gradual increase in the area covered by bright hummocks toward the western edge of the image. A more recent palimpsest-forming impact to the south has peppered this area with chains and clusters of secondary craters ranging from 5.7 to 1.2 kilometers (3.5 to 0.7 miles) in diameter. The image covers an area of 73 by 65 kilometers (45 by 40 miles).

    The Jet Propulsion Laboratory, Pasadena, CA manages the Galileo mission for NASA's Office of Space Science, Washington, DC. JPL is an operating division of California Institute of Technology (Caltech).

    This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://galileo.jpl.nasa.gov. Background information and educational context for the images can be found at URL http://www.jpl.nasa.gov/galileo/sepo

  6. Aniakchak Crater, Alaska Peninsula

    USGS Publications Warehouse

    Smith, Walter R.

    1925-01-01

    The discovery of a gigantic crater northwest of Aniakchak Bay (see fig. 11) closes what had been thought to be a wide gap in the extensive series of volcanoes occurring at irregular intervals for nearly 600 miles along the axial line of the Alaska Peninsula and the Aleutian Islands. In this belt there are more active and recently active volcanoes than in all the rest of North America. Exclusive of those on the west side of Cook Inlet, which, however, belong to the same group, this belt contains at least 42 active or well-preserved volcanoes and about half as many mountains suspected or reported to be volcanoes. The locations of some of these mountains and the hot springs on the Alaska Peninsula and the Aleutian Islands are shown on a map prepared by G. A. Waring. Attention has been called to these volcanoes for nearly two centuries, but a record of their activity since the discovery of Alaska is far from being complete, and an adequate description of them as a group has never been written. Owing to their recent activity or unusual scenic beauty, some of the best known of the group are Mounts Katmai, Bogoslof, and Shishaldin, but there are many other beautiful and interesting cones and craters.

  7. Solar activity and Perseid meteor heights

    NASA Astrophysics Data System (ADS)

    Buček, M.; Porubčan, V.; Zigo, P.

    2012-04-01

    Photographic meteor heights of the Perseid meteoroid stream compiled in the IAU Meteor Data Center catalogue observed in 1939-1992, covering five solar activity cycles, are analyzed and their potential variation within a solar activity cycle is investigated and discussed. Of the 673 Perseids selected from the catalogue, the variations of the heights for three independent sets: 524 Perseids with known information on both heights, 397 with known brightness and 279 with the geocentric velocity within a one sigma limit, were investigated. The observed beginning and endpoint heights of the Perseids, normalized for the geocentric velocity and the absolute photographic magnitude correlated with the solar activity represented by the relative sunspot number R, do not exhibit a variation consistent with the solar activity cycle. The result, confirmed also by the correlation analysis, is derived for the mass ranges of larger meteoroids observed by photographic techniques. However, a possible variation of meteor heights controlled by solar activity for smaller meteoroids detected by television and radio techniques remains still open and has to be verified.

  8. JEM-EUSO: Meteor and nuclearite observations

    NASA Astrophysics Data System (ADS)

    Adams, J. H.; Ahmad, S.; Albert, J.-N.; Allard, D.; Anchordoqui, L.; Andreev, V.; Anzalone, A.; Arai, Y.; Asano, K.; Ave Pernas, M.; Baragatti, P.; Barrillon, P.; Batsch, T.; Bayer, J.; Bechini, R.; Belenguer, T.; Bellotti, R.; Belov, K.; Berlind, A. A.; Bertaina, M.; Biermann, P. L.; Biktemerova, S.; Blaksley, C.; Blanc, N.; Błȩcki, J.; Blin-Bondil, S.; Blümer, J.; Bobik, P.; Bogomilov, M.; Bonamente, M.; Briggs, M. S.; Briz, S.; Bruno, A.; Cafagna, F.; Campana, D.; Capdevielle, J.-N.; Caruso, R.; Casolino, M.; Cassardo, C.; Castellinic, G.; Catalano, C.; Catalano, G.; Cellino, A.; Chikawa, M.; Christl, M. J.; Cline, D.; Connaughton, V.; Conti, L.; Cordero, G.; Crawford, H. J.; Cremonini, R.; Csorna, S.; Dagoret-Campagne, S.; de Castro, A. J.; De Donato, C.; de la Taille, C.; De Santis, C.; del Peral, L.; Dell'Oro, A.; De Simone, N.; Di Martino, M.; Distratis, G.; Dulucq, F.; Dupieux, M.; Ebersoldt, A.; Ebisuzaki, T.; Engel, R.; Falk, S.; Fang, K.; Fenu, F.; Fernández-Gómez, I.; Ferrarese, S.; Finco, D.; Flamini, M.; Fornaro, C.; Franceschi, A.; Fujimoto, J.; Fukushima, M.; Galeotti, P.; Garipov, G.; Geary, J.; Gelmini, G.; Giraudo, G.; Gonchar, M.; González Alvarado, C.; Gorodetzky, P.; Guarino, F.; Guzmán, A.; Hachisu, Y.; Harlov, B.; Haungs, A.; Hernández Carretero, J.; Higashide, K.; Ikeda, D.; Ikeda, H.; Inoue, N.; Inoue, S.; Insolia, A.; Isgrò, F.; Itow, Y.; Joven, E.; Judd, E. G.; Jung, A.; Kajino, F.; Kajino, T.; Kaneko, I.; Karadzhov, Y.; Karczmarczyk, J.; Karus, M.; Katahira, K.; Kawai, K.; Kawasaki, Y.; Keilhauer, B.; Khrenov, B. A.; Kim, J.-S.; Kim, S.-W.; Kim, S.-W.; Kleifges, M.; Klimov, P. A.; Kolev, D.; Kreykenbohm, I.; Kudela, K.; Kurihara, Y.; Kusenko, A.; Kuznetsov, E.; Lacombe, M.; Lachaud, C.; Lee, J.; Licandro, J.; Lim, H.; López, F.; Maccarone, M. C.; Mannheim, K.; Maravilla, D.; Marcelli, L.; Marini, A.; Martinez, O.; Masciantonio, G.; Mase, K.; Matev, R.; Medina-Tanco, G.; Mernik, T.; Miyamoto, H.; Miyazaki, Y.; Mizumoto, Y.; Modestino, G.; Monaco, A.; Monnier-Ragaigne, D.; Morales de los Ríos, J. A.; Moretto, C.; Morozenko, V. S.; Mot, B.; Murakami, T.; Murakami, M. Nagano; Nagata, M.; Nagataki, S.; Nakamura, T.; Napolitano, T.; Naumov, D.; Nava, R.; Neronov, A.; Nomoto, K.; Nonaka, T.; Ogawa, T.; Ogio, S.; Ohmori, H.; Olinto, A. V.; Orleański, P.; Osteria, G.; Panasyuk, M. I.; Parizot, E.; Park, I. H.; Park, H. W.; Pastircak, B.; Patzak, T.; Paul, T.; Pennypacker, C.; Perez Cano, S.; Peter, T.; Picozza, P.; Pierog, T.; Piotrowski, L. W.; Piraino, S.; Plebaniak, Z.; Pollini, A.; Prat, P.; Prévôt, G.; Prieto, H.; Putis, M.; Reardon, P.; Reyes, M.; Ricci, M.; Rodríguez, I.; Rodríguez Frías, M. D.; Ronga, F.; Roth, M.; Rothkaehl, H.; Roudil, G.; Rusinov, I.; Rybczyński, M.; Sabau, M. D.; Sáez-Cano, G.; Sagawa, H.; Saito, A.; Sakaki, N.; Sakata, M.; Salazar, H.; Sánchez, S.; Santangelo, A.; Santiago Crúz, L.; Sanz Palomino, M.; Saprykin, O.; Sarazin, F.; Sato, H.; Sato, M.; Schanz, T.; Schieler, H.; Scotti, V.; Segreto, A.; Selmane, S.; Semikoz, D.; Serra, M.; Sharakin, S.; Shibata, T.; Shimizu, H. M.; Shinozaki, K.; Shirahama, T.; Siemieniec-Oziȩbło, G.; Silva López, H. H.; Sledd, J.; Słomińska, K.; Sobey, A.; Sugiyama, T.; Supanitsky, D.; Suzuki, M.; Szabelska, B.; Szabelski, J.; Tajima, F.; Tajima, N.; Tajima, T.; Takahashi, Y.; Takami, H.; Takeda, M.; Takizawa, Y.; Tenzer, C.; Tibolla, O.; Tkachev, L.; Tokuno, H.; Tomida, T.; Tone, N.; Toscano, S.; Trillaud, F.; Tsenov, R.; Tsunesada, Y.; Tsuno, K.; Tymieniecka, T.; Uchihori, Y.; Unger, M.; Vaduvescu, O.; Valdés-Galicia, J. F.; Vallania, P.; Valore, L.; Vankova, G.; Vigorito, C.; Villaseñor, L.; von Ballmoos, P.; Wada, S.; Watanabe, J.; Watanabe, S.; Watts, J.; Weber, M.; Weiler, T. J.; Wibig, T.; Wiencke, L.; Wille, M.; Wilms, J.; Włodarczyk, Z.; Yamamoto, T.; Yamamoto, Y.; Yang, J.; Yano, H.; Yashin, I. V.; Yonetoku, D.; Yoshida, K.; Yoshida, S.; Young, R.; Zotov, M. Yu.; Zuccaro Marchi, A.

    2015-11-01

    Meteor and fireball observations are key to the derivation of both the inventory and physical characterization of small solar system bodies orbiting in the vicinity of the Earth. For several decades, observation of these phenomena has only been possible via ground-based instruments. The proposed JEM-EUSO mission has the potential to become the first operational space-based platform to share this capability. In comparison to the observation of extremely energetic cosmic ray events, which is the primary objective of JEM-EUSO, meteor phenomena are very slow, since their typical speeds are of the order of a few tens of km/sec (whereas cosmic rays travel at light speed). The observing strategy developed to detect meteors may also be applied to the detection of nuclearites, which have higher velocities, a wider range of possible trajectories, but move well below the speed of light and can therefore be considered as slow events for JEM-EUSO. The possible detection of nuclearites greatly enhances the scientific rationale behind the JEM-EUSO mission.

  9. Photometric stellar catalogue for TV meteor astronomy

    NASA Astrophysics Data System (ADS)

    Leonov, V. A.; Bagrov, A. V.

    2016-01-01

    Photometry for ordinary astrophysics was carefully developed for its own purposes. As stars radiation is very similar to the blackbody radiation, astronomers measure star illumination in wide or narrow calibrated spectral bands. This is enough for star photometry with precise accuracy and for measuring their light flux in these bands in energetic units. Meteors are moving objects and do not allow collection of more photons then they emit. So meteor observers use the whole spectral band that can be covered by sensitivity of their light sensors. This is why measurements of stellar magnitudes of background stars by these sensors are not the same as catalogued star brightness in standard photometric spectral bands. Here we present a special photometric catalogue of 93 bright non-variable stars of the northern hemisphere, that can be used by meteor observers of standard background whose brightness are calculated in energetic units as well as in non-systematic stellar magnitudes in spectral wavelength of the WATEC 902 sensitivity.

  10. Radar observations of the Volantids meteor shower

    NASA Astrophysics Data System (ADS)

    Younger, J.; Reid, I.; Murphy, D.

    2016-01-01

    A new meteor shower occurring for the first time on 31 December 2015 in the constellation Volans was identified by the CAMS meteor video network in New Zealand. Data from two VHF meteor radars located in Australia and Antarctica have been analyzed using the great circle method to search for Volantids activity. The new shower was found to be active for at least three days over the period 31 December 2015 - 2 January 2016, peaking at an apparent radiant of R.A. = 119.3 ± 3.7, dec. = -74.5 ± 1.9 on January 1st. Measurements of meteoroid velocity were made using the Fresnel transform technique, yielding a geocentric shower velocity of 28.1 ± 1.8 km s-1. The orbital parameters for the parent stream are estimated to be a = 2.11 AU, e = 0.568, i = 47.2°, with a perihelion distance of q = 0.970 AU.

  11. Comet outbursts and the meteor showers

    NASA Astrophysics Data System (ADS)

    Guliyev, A. S.; Kokhirova, G. I.; Poladova, U. D.

    2014-07-01

    The features of 116 comets that have shown an outbursts in their brightness, are considered in the paper. The hypothesis on that the outburst in activity of comets are caused by their passing through meteoroid streams is studied. For this purpose the orbital elements of such comets relative to the planes of motion of 68 meteor showers from Cook's catalogue are analyzed. It was found that four of the nearest and distant nodes of comet orbits relative to the planes of motion of nine meteor showers exceeds the average statistical background with confidence probability from 0.90 to 0.95, and more than 0.95, respectively. The October Draconids, Aurigids, kappa-Serpentids, delta-Draconids, sigma-Hydrids}, Coma Berenicids, Leonids, Leo Minorids, and Perseids showers are the most effective. The results of calculation show that often, the comets outbursts may be caused by collisions of comets with meteoroids under the passing through the meteoroid streams that are producing listed meteor showers as well as solar activity.

  12. Eastern Floor of Holden Crater

    NASA Technical Reports Server (NTRS)

    2002-01-01

    (Released 15 April 2002) The Science Today's THEMIS image covers territory on the eastern floor of Holden Crater, which is located in region of the southern hemisphere called Noachis Terra. Holden Crater is 154 km in diameter and named after American Astronomer Edward Holden (1846-1914). This image shows a mottled surface with channels, hills, ridges and impact craters. The largest crater seen in this image is 5 km in diameter. This crater has gullies and what appears to be horizontal layers in its walls. The Story With its beautiful symmetry and gullies radially streaming down to the floor, the dominant crater in this image is an impressive focal point. Yet, it is really just a small crater within a much larger one named Holden Crater. Take a look at the context image to the right to see just how much bigger Holden Crater is. Then come back to the image strip that shows the mottled surface of Holden Crater's eastern floor in greater detail, and count how many hills, ridges, channels, and small impact craters can be seen. No perfectly smooth terrain abounds there, that's for sure. The textured terrain of Holden Crater has been particularly intriguing ever since the Mars Orbital Camera on the Mars Global Surveyor spacecraft found evidence of sedimentary rock layers there that might have formed in lakes or shallow seas in Mars' ancient past. This finding suggests that Mars may have been more like Earth long ago, with water on its surface. Holden Crater might even have held a lake long ago. No one knows for sure, but it's an exciting possibility. Why? If water was once on the surface of Mars long enough to form sedimentary materials, maybe it was there long enough for microbial life to have developed too. (Life as we know it just isn't possible without the long-term presence of liquid water.) The question of life on the red planet is certainly tantalizing, but scientists will need to engage in a huge amount of further investigation to begin to know the answer. That

  13. Degradation of Victoria crater, Mars

    USGS Publications Warehouse

    Grant, J. A.; Wilson, S.A.; Cohen, B. A.; Golombek, M.P.; Geissler, P.E.; Sullivan, R.J.; Kirk, R.L.; Parker, T.J.

    2008-01-01

    The ???750 m diameter and ???75 m deep Victoria crater in Meridiani Planum, Mars, is a degraded primary impact structure retaining a ???5 m raised rim consisting of 1-2 m of uplifted rocks overlain by ???3 m of ejecta at the rim crest. The rim is 120-220 m wide and is surrounded by a dark annulus reaching an average of 590 m beyond the raised rim. Comparison between observed morphology and that expected for pristine craters 500-750 m across indicates that the original, pristine crater was close to 600 m in diameter. Hence, the crater has been erosionally widened by ???150 m and infilled by ???50 m of sediments. Eolian processes are responsible for most crater modification, but lesser mass wasting or gully activity contributions cannot be ruled out. Erosion by prevailing winds is most significant along the exposed rim and upper walls and accounts for ???50 m widening across a WNW-ESE diameter. The volume of material eroded from the crater walls and rim is ???20% less than the volume of sediments partially filling the crater, indicating eolian infilling from sources outside the crater over time. The annulus formed when ???1 m deflation of the ejecta created a lag of more resistant hematite spherules that trapped <10-20 cm of darker, regional basaltic sands. Greater relief along the rim enabled meters of erosion. Comparison between Victoria and regional craters leads to definition of a crater degradation sequence dominated by eolian erosion and infilling over time. Copyright 2008 by the American Geophysical Union.

  14. From Crater to Graph: Manual and Automated Crater Counting Techniques

    NASA Astrophysics Data System (ADS)

    Plesko, C. S.; Werner, S. C.; Brumby, S. P.; Foing, B. H.; Asphaug, E.; Neukum, G.; Team, H.; Team, I.

    2005-12-01

    Impact craters are some of the most abundant, and most interesting features on Mars. They hold a wealth of information about Martian geology, providing clues to the relative age, local composition and erosional history of the surface. A great deal of effort has been expended to count and understand the nature of planetary crater populations (Hartman and Neukum, 2001). Highly trained experts have developed personal methods for conducting manual crater surveys. In addition, several efforts are underway to automate this process in order to keep up with the rapid increase in planetary surface image data. These efforts make use of a variety of methods, including the direct application of traditional image processing algorithms such as the Hough transform, and recent developments in genetic programming, an artificial intelligence-based technique, in which manual crater surveys are used as examples to `grow' or `evolve' crater counting algorithms. (Plesko, C. S. et al., LPSC 2005, Kim, J. R. et al., LPSC 2001, Michael, G. G. P&SS 2003, Earl, J. et al, LPSC 2005) In this study we examine automated crater counting techniques, and compare them with traditional manual techniques on MOC imagery, and demonstrate capabilities for the analysis of multi-spectral and HRSC Digital Terrain Model data as well. Techniques are compared and discussed to define and develop a robust automated crater detection strategy.

  15. Secondary craters on Europa and implications for cratered surfaces.

    PubMed

    Bierhaus, Edward B; Chapman, Clark R; Merline, William J

    2005-10-20

    For several decades, most planetary researchers have regarded the impact crater populations on solid-surfaced planets and smaller bodies as predominantly reflecting the direct ('primary') impacts of asteroids and comets. Estimates of the relative and absolute ages of geological units on these objects have been based on this assumption. Here we present an analysis of the comparatively sparse crater population on Jupiter's icy moon Europa and suggest that this assumption is incorrect for small craters. We find that 'secondaries' (craters formed by material ejected from large primary impact craters) comprise about 95 per cent of the small craters (diameters less than 1 km) on Europa. We therefore conclude that large primary impacts into a solid surface (for example, ice or rock) produce far more secondaries than previously believed, implying that the small crater populations on the Moon, Mars and other large bodies must be dominated by secondaries. Moreover, our results indicate that there have been few small comets (less than 100 m diameter) passing through the jovian system in recent times, consistent with dynamical simulations. PMID:16237437

  16. Analysis of Historical Meteor and Meteor shower Records: Korea, China and Japan

    NASA Astrophysics Data System (ADS)

    Yang, Hong-Jin; Park, Changbom; Park, Myeong-Gu

    2015-03-01

    We have compiled and analyzed historical meter and meteor shower records in Korean, Chinese, and Japanese chronicles. We have confirmed the peaks of Perseids and an excess due to the mixture of Orionids, north-Taurids, or Leonids through the Monte-Carlo test from the Korean records. The peaks persist for almost one thousand years. We have also analyzed seasonal variation of sporadic meteors from Korean records. Major features in Chinese meteor shower records are quite consistent with those of Korean records, particularly for the last millennium. Japanese records also show Perseids feature and Orionids/north-Taurids/Leonids feature, although they are less prominent compared to those of Korean or Chinese records.

  17. Floor-fractured crater models for igneous crater modification on Venus

    NASA Technical Reports Server (NTRS)

    Wichman, R. W.; Schultz, P. H.

    1992-01-01

    Although crater modification on the Earth, Moon, and Mars results from surface erosion and crater infilling, a significant number of craters on the Moon also exhibit distinctive patterns of crater-centered fracturing and volcanism that can be modeled as the result of igneous crater modification. Here, we consider the possible effects of Venus surface conditions on this model, describe two examples of such crater modification, and then briefly discuss the constraints these craters place on conditions at depth.

  18. Shaping Arizona's Future: Head Start in Arizona. Annual Report, 2001.

    ERIC Educational Resources Information Center

    Nagle, Ami; Walker, Laura

    The Arizona Head Start Association is a federation of public and private organizations that provide Head Start programs and work to improve the conditions of children in the state. This annual report describes the operation of the Head Start program in Arizona for 2000-2001. Beginning with an introductory letter from the president of the Arizona…

  19. Geology of five small Australian impact craters

    USGS Publications Warehouse

    Shoemaker, E.M.; Macdonald, F.A.; Shoemaker, C.S.

    2005-01-01

    Here we present detailed geological maps and cross-sections of Liverpool, Wolfe Creek, Boxhole, Veevers and Dalgaranga craters. Liverpool crater and Wolfe Creek Meteorite Crater are classic bowlshaped, Barringer-type craters, Liverpool was likely formed during the Neoproterozoic and was filled and covered with sediments soon thereafter. In the Cenozoic, this cover was exhumed exposing the crater's brecciated wall rocks. Wolfe Creek Meteorite Crater displays many striking features, including well-bedded ejecta units, crater-floor faults and sinkholes, a ringed aeromagnetic anomaly, rim-skirting dunes, and numerous iron-rich shale balls. Boxhole Meteorite Crater, Veevers Meteorite Crater and Dalgaranga crater are smaller, Odessa-type craters without fully developed, steep, overturned rims. Boxhole and Dalgaranga craters are developed in highly follated Precambrian basement rocks with a veneer of Holocene colluvium. The pre-existing structure at these two sites complicates structural analyses of the craters, and may have influenced target deformation during impact. Veevers Meteorite Crater is formed in Cenozoic laterites, and is one of the best-preserved impact craters on Earth. The craters discussed herein were formed in different target materials, ranging from crystalline rocks to loosely consolidated sediments, containing evidence that the impactors struck at an array of angles and velocities. This facilitates a comparative study of the influence of these factors on the structural and topographic form of small impact craters. ?? Geological Society of Australia.

  20. Meteoric water in metamorphic core complexes

    NASA Astrophysics Data System (ADS)

    Teyssier, Christian; Mulch, Andreas

    2015-04-01

    The trace of surface water has been found in all detachment shear zones that bound the Cordilleran metamorphic core complexes of North America. DeltaD values of mica fish in detachment mylonites demonstrate that these synkinematic minerals grew in the presence of meteoric water. Typically deltaD values are very negative (-120 to -160 per mil) corresponding to deltaD values of water that are < -100 per mil given the temperature of water-mica isotopic equilibration (300-500C). From British Columbia (Canada) to Nevada (USA) detachment systems bound a series of core complexes: the Thor-Odin, Valhalla, Kettle-Okanogan, Bitterroot -Anaconda, Pioneer, Raft River, Ruby Mountain, and Snake Range. The bounding shear zones range in thickness from ~100 m to ~1 km, and within the shear zones, meteoric water signature is recognized over 10s to 100s of meters beneath the detachment fault. The age of shearing ranges generally from Eocene in the N (~50-45 Ma) to Oligo-Miocene in the S (25-15 Ma). DeltaD water values derived from mica fish in shear zones are consistent with supradetachment basin records of the same age brackets and can be used for paleoaltimetry if coeval isotopic records from near sea level are available. Results show that a wave of topography (typically 4000-5000 m) developed from N to S along the Cordillera belt from Eocene to Miocene, accompanied by the propagation of extensional deformation and volcanic activity. In addition, each detachment system informs a particular extensional detachment process. For example, the thick Thor-Odin detachment shear zone provides sufficient age resolution to indicate the downward propagation of shearing and the progressive incorporation of footwall rocks into the hanging wall. The Kettle detachment provides a clear illustration of the dependence of fluid circulation on dynamic recrystallization processes. The Raft River system consists of a thick Eocene shear zone that was overprinted by Miocene shearing; channels of meteoric

  1. Meteor observations of the Perseids 2015 using the SPOSH cameras

    NASA Astrophysics Data System (ADS)

    Margonis, A.; Oberst, J.; Christou, A.; Elgner, S.; Sohl, F.; Flohrer, J.; Intzekara, D.; Wahl, D.

    2015-10-01

    We will organize a meteor campaign in Greece focusing on the observation of the meteor activity during this year's maximum of the Perseids meteor shower. Double-station observations will be carried out from 10th until 14th of August using SPOSH cameras. During this period, we anticipate rates up to 100 Perseids per hour. The participation of graduate students during the observations and the data reduction will strengthen the educational aspect of the campaign

  2. On the origin of ringing irregularities - A meteor hypothesis

    NASA Technical Reports Server (NTRS)

    Deshpande, M. R.; Vats, H. O.; Trivedi, A. I.

    1978-01-01

    Isolated ionospheric irregularities produce oscillating diffraction patterns on the ground. In the present study typical physical properties such as density, size, etc. of these irregularities are estimated on the basis of diffraction pattern characteristics. These properties agree well with those of meteor trail ionization and it has been found that most of these oscillating irregularities occur on meteor shower days. It is therefore suggested that the oscillating irregularities are caused by meteor showers.

  3. Results of the IMO Video Meteor Network - May 2014

    NASA Astrophysics Data System (ADS)

    Molau, Sirko; Kac, Javor; Crivello, Stefano; Stomeo, Enrico; Barentsen, Geert; Goncalves, Rui; Igaz, Antal

    2014-08-01

    In 2014 May, over 18 000 meteors were recorded in almost 7 700 hours of effective observing time by 81 cameras of the IMO Video Meteor Network. The flux density profile of the η-Aquariids is presented over the full activity period, based on over 5 000 shower meteors recorded over the last four years. The activity profile is also presented for the η-Lyrids, based on data obtained during the years 2011 to 2014.

  4. Mesospheric observations by a forward scattering meteor radar basic setup

    NASA Astrophysics Data System (ADS)

    Madkour, Waleed; Yamamoto, Masa-yuki

    2016-08-01

    The durations of radio echo signals scattered from meteor ionized trails might not show a consistent increase corresponding to higher density trails due to the rapid removal of meteor ions at certain heights. Several studies have concluded the dominant role of the secondary ozone layer over diffusion in the removal of the meteor trails below 95 km through chemical oxidization of the meteor ions. Using a basic setup configuration of a forward scattering receiver, a trial to observe the mesospheric ozone concentration was performed by analyzing the meteor echo duration distributions. The forward scattered meteor echoes have the advantage of long durations that can enable observing the transition from the diffusion-removal regime to the chemistry-removal regime. The cumulative meteor echo duration distribution of two meteor showers, the Perseids and the Geminids, were analyzed over 10 years and the chemistry-removal regime in each shower was observed. The knee duration position at which a drop in the number of long overdense meteor echoes starts differed by around 30 seconds between the two showers. As the secondary ozone concentration is inversely related to the solar activity level, the Geminids 2011 corresponding to a high solar activity level showed a significant higher counts of long duration echoes compared to the Geminids 2006 during a low activity level, with the knee position shifted to longer duration. The knee positions obtained during the two distinct meteor showers and the two half solar cycle points are generally in agreement with the mesospheric ozone conditions expected in each case. However, continuous data record is required for the other meteor showers and the sporadic meteors at different heights to observe the mesospheric ozone concentration vertically and the full 11-years solar cycle.

  5. Multi-Year CMOR Observations of the Geminid Meteor Shower

    NASA Technical Reports Server (NTRS)

    Webster, A. R.; Jones, J.

    2011-01-01

    The three-station Canadian Meteor Orbit Radar (CMOR) is used here to examine the Geminid meteor shower with respect to variation in the stream properties including the flux and orbital elements over the period of activity in each of the consecutive years 2005 2008 and the variability from year to year. Attention is given to the appropriate choice and use of the D-criterion in the separating the shower meteors from the sporadic background.

  6. Pollack Crater's White Rock

    NASA Technical Reports Server (NTRS)

    2008-01-01

    This image of White Rock in Pollack crater was taken by the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) on February 3, 2007 at 1750 UTC (12:50 p.m. EST), near 8 degrees south latitude, 25 degrees east longitude. The CRISM image was taken in 544 colors covering 0.36-3.92 micrometers, and shows features as small as 40 meters (132 feet) across. The region covered is roughly 20 kilometers (12 miles) long and 10 kilometers (6 miles) wide at its narrowest point.

    First imaged by the Mariner 9 spacecraft in 1972, the enigmatic group of wind-eroded ridges known as White Rock has been the subject of many subsequent investigations. White Rock is located on the floor of Pollack Crater in the Sinus Sabaeus region of Mars. It measures some 15 by 18 kilometers (9 by 11 miles) and was named for its light-colored appearance. In contrast-enhanced images, the feature's higher albedo or reflectivity compared with the darker material on the floor of the crater makes it appear white. In reality, White Rock has a dull, reddish color more akin to Martian dust. This higher albedo as well as its location in a topographic low suggested to some researchers that White Rock may be an eroded remnant of an ancient lake deposit. As water in a desert lake on Earth evaporates, it leaves behind white-colored salts that it leached or dissolved out of the surrounding terrain. These salt deposits may include carbonates, sulfates, and chlorides.

    In 2001, the Thermal Emission Spectrometer (TES) on NASA's Mars Global Surveyor measured White Rock and found no obvious signature of carbonates or sulfates, or any other indication that White Rock holds evaporite minerals. Instead, it found Martian dust.

    CRISM's challenge was to obtain greater detail of White Rock's mineralogical composition and how it formed. The instrument operates at a different wavelength range than TES, giving it greater sensitivity to carbonate, sulfate and phyllosilicate (clay-like) minerals. It also

  7. Clouds Over Crater Rim

    NASA Technical Reports Server (NTRS)

    2004-01-01

    Clouds above the rim of 'Endurance Crater' in this image from NASA's Mars Exploration Rover Opportunity can remind the viewer that Mars, our celestial neighbor, is subject to weather. On Earth, clouds like these would be referred to as 'cirrus' or the aptly nicknamed 'mares' tails.' These clouds occur in a region of strong vertical shear. The cloud particles (ice in this martian case) fall out, and get dragged along away from the location where they originally condensed, forming characteristic streamers. Opportunity took this picture with its navigation camera during the rover's 269th martian day (Oct. 26, 2004).

    The mission's atmospheric science team is studying cloud observations to deduce seasonal and time-of-day behavior of the clouds. This helps them gain a better understanding of processes that control cloud formation.

  8. Pwyll Crater on Europa

    NASA Technical Reports Server (NTRS)

    1997-01-01

    This enhanced color image of the region surrounding the young impact crater Pwyll on Jupiter's moon Europa was produced by combining low resolution color data with a higher resolution mosaic of images obtained on December 19, 1996 by the Solid State Imaging (CCD) system aboard NASA's Galileo spacecraft. This region is on the trailing hemisphere of the satellite, centered at 11 degrees South and 276 degrees West, and is about 1240 kilometers across. North is toward the top of the image, and the sun illuminates the surface from the east.

    The 26 kilometer diameter impact crater Pwyll, just below the center of the image, is thought to be one of the youngest features on the surface of Europa. The diameter of the central dark spot, ejecta blasted from beneath Europa's surface, is approximately 40 kilometers, and bright white rays extend for over a thousand kilometers in all directions from the impact site. These rays cross over many different terrain types, indicating that they are younger than anything they cross. Their bright white color may indicate that they are composed of fresh, fine water ice particles, as opposed to the blue and brown tints of older materials elsewhere in the image.

    Also visible in this image are a number of the dark lineaments which are called 'triple bands' because they have a bright central stripe surrounded by darker material. Scientists can use the order in which these bands cross each other to determine their relative ages, as they attempt to reconstruct the geologic history of Europa.

    The Jet Propulsion Laboratory, Pasadena, CA manages the mission for NASA's Office of Space Science, Washington, DC.

    This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://galileo.jpl.nasa.gov. Background information and educational context for the images can be found at URL http://www.jpl.nasa.gov/galileo/sepo

  9. Results of the IMO Video Meteor Network - December 2015

    NASA Astrophysics Data System (ADS)

    Molau, S.; Crivello, S.; Goncalves, R.; Saraiva, C.; Stomeo, E.; Kac, J.

    2016-04-01

    In 2015 December, 80 cameras of the IMO Video Meteor Network recorded over 60 000 meteors in more than 10 600 hours of observing time. The flux density profile is presented for the Geminids and compared to previous years. The population index profile of the Geminids is also presented. The activity of the Ursids was slightly enhanced again. The flux density profile is presented and compared to profiles since 2011. The annual summary of the 2015 IMO Video Meteor Network observations is presented. More than 480 000 meteors were recorded in almost 122 000 hours of observing time.

  10. Results of the IMO Video Meteor Network - December 2014

    NASA Astrophysics Data System (ADS)

    Molau, Sirko; Kac, Javor; Crivello, Stefano; Stomeo, Enrico; Barentsen, Geert; Goncalves, Rui; Saraiva, Carlos; Maciewski, Maciej; Maslov, Mikhail

    2015-04-01

    In 2014 December, 85 cameras of the IMO Video Meteor Network recorded almost 45 000 meteors in over 9 300 hours of observing time. The flux density profile is presented for the Geminids, as well as the population index profile around the maximum. A short-lasting outburst of the Ursids occurred on 2014 December 23 at 0h UT that reached a flux density of 60 meteoroids per 1 000 km^2 per hour in a 30-minute interval. The annual summary of the 2014 IMO Video Meteor Network observations is presented. More than 367 000 meteors were recorded in almost 100 000 hours of observing time.

  11. First results of Bosnia-Herzegovina Meteor Network (BHMN)

    NASA Astrophysics Data System (ADS)

    Mujić, N.; Muminović, M.

    2015-01-01

    Inspired by similar networks in the region, a video meteor network began since the spring of 2013 in Bosnia and Herzegovina which currently includes eight stations. Further expansion of the network is under preparation by setting up another 2 stations. The Network is managed by the Astronomical Society Orion Sarajevo together with the Federal Hydrometeorological Institute in Sarajevo whose meteorological stations were used for the installation of the cameras. By mid-June 2015 the cameras of the BH meteor network had recorded over 20000 meteors and we had calculated more than 4000 orbits. In this paper we present the results of the first two years of operation of our meteor network.

  12. Optical and Radar Measurements of the Meteor Speed Distribution

    NASA Technical Reports Server (NTRS)

    Moorhead, A. V.; Brown, P. G.; Campbell-Brown, M. D.; Kingery, A.; Cooke, W. J.

    2016-01-01

    The observed meteor speed distribution provides information on the underlying orbital distribution of Earth-intersecting meteoroids. It also affects spacecraft risk assessments; faster meteors do greater damage to spacecraft surfaces. Although radar meteor networks have measured the meteor speed distribution numerous times, the shape of the de-biased speed distribution varies widely from study to study. Optical characterizations of the meteoroid speed distribution are fewer in number, and in some cases the original data is no longer available. Finally, the level of uncertainty in these speed distributions is rarely addressed. In this work, we present the optical meteor speed distribution extracted from the NASA and SOMN allsky networks [1, 2] and from the Canadian Automated Meteor Observatory (CAMO) [3]. We also revisit the radar meteor speed distribution observed by the Canadian Meteor Orbit Radar (CMOR) [4]. Together, these data span the range of meteoroid sizes that can pose a threat to spacecraft. In all cases, we present our bias corrections and incorporate the uncertainty in these corrections into uncertainties in our de-biased speed distribution. Finally, we compare the optical and radar meteor speed distributions and discuss the implications for meteoroid environment models.

  13. METEOR - an artificial intelligence system for convective storm forecasting

    SciTech Connect

    Elio, R.; De haan, J.; Strong, G.S.

    1987-03-01

    An AI system called METEOR, which uses the meteorologist's heuristics, strategies, and statistical tools to forecast severe hailstorms in Alberta, is described, emphasizing the information and knowledge that METEOR uses to mimic the forecasting procedure of an expert meteorologist. METEOR is then discussed as an AI system, emphasizing the ways in which it is qualitatively different from algorithmic or statistical approaches to prediction. Some features of METEOR's design and the AI techniques for representing meteorological knowledge and for reasoning and inference are presented. Finally, some observations on designing and implementing intelligent consultants for meteorological applications are made. 7 references.

  14. The 2014 KCG Meteor Outburst: Clues to a Parent Body

    NASA Astrophysics Data System (ADS)

    Moorhead, Althea V.; Brown, Peter G.; Spurný, Pavel; Cooke, William J.; Shrbený, Lukáš

    2015-10-01

    The κ Cygnid (KCG) meteor shower exhibited unusually high activity in 2014, producing ten times the flux of KCG meteors compared to normal years. The shower was detected during the routine operation of several radar and optical systems. Meteoroids associated with the outburst ranged from approximately 10-6-10-5 kg for radar meteors and from 10-3 to 2 kg for optical meteors. The Canadian Meteor Orbit Radar, Czech part of the European Fireball Network, and NASA All Sky and Southern Ontario Meteor Networks produced thousands of KCG meteor trajectories in total. Using these data, we have undertaken a new and improved characterization of the dynamics of this little-studied, variable meteor shower. The KCGs have a diffuse radiant and a significant spread in orbital characteristics. Our analysis of the highest quality KCG trajectories reveals concentrations of stream members near major resonances with Jupiter. We conducted a new search for parent bodies and find that several known asteroids are orbitally similar to the KCGs. Our meteor stream simulations show that the two best parent body candidates readily transfer meteoroids to the Earth in recent centuries, but neither produces a match to the KCG radiant, velocity, and solar longitude. We nevertheless identify asteroid 2001 MG1 as a promising parent body candidate.

  15. Arizona in Books for Children.

    ERIC Educational Resources Information Center

    Choncoff, Mary, Comp.

    The bibliography of approximately 550 entries is a sample of those available on Arizona for elementary school students. Topics include Arizona history and culture, Mexican lore, and information about Navajo Indians. Although some of the titles are too difficult for the reading level of elementary school students, they are included because no other…

  16. Arizona Conserve Water Educators Guide

    ERIC Educational Resources Information Center

    Project WET Foundation, 2007

    2007-01-01

    This award-winning, 350-page, full-color book provides a thorough study of Arizona water resources from a water conservation perspective. Its background section contains maps, graphs, diagrams and photos that facilitate the teaching of 15 interactive, multi-disciplinary lessons to K-12 students. In addition, 10 Arizona case studies are highlighted…

  17. Tuition in Arizona Community Colleges.

    ERIC Educational Resources Information Center

    Puyear, Don

    This document's purpose was to provide a broader context for State Board members as they considered the tuition rate requests for Arizona community college in April of 1997. Arizona's State Constitution calls for public higher education to be as nearly free as possible, yet tuition has become an increasingly important source of revenue for the…

  18. Largest impact craters on Venus

    NASA Technical Reports Server (NTRS)

    Ivanov, B. A.; Weitz, C. M.; Basilevsky, A. T.

    1992-01-01

    High-resolution radar images from the Magellan spacecraft have allowed us to perform a detailed study on 25 large impact craters on Venus with diameters from 70 to 280 km. The dimension of these large craters is comparable with the characteristic thickness of the venusian lithosphere and the atmospheric scale height. Some physical parameters for the largest impact craters on Venus (LICV), such as depth, ring/diameter ratio, and range of ballistic ejecta deposits, have been obtained from the SAR images and the altimetry dataset produced by MIT. Data related to each of these parameters is discussed.

  19. King of the Crater Ledge

    NASA Technical Reports Server (NTRS)

    2004-01-01

    This image shows a screenshot from software used by engineers to drive the Mars Exploration Rover Spirit up toward the rim of the crater dubbed 'Bonneville.' The software simulates the rover's movements across the martian terrain, helping to plot a safe course. The virtual 3-D world around the rover is built from images taken by Spirit's stereo navigation cameras. Regions for which the rover has not yet acquired 3-D data are represented in beige.

    In this picture, the rover is seen in its projected final position at the rim of the crater. Later today, Spirit will travel 16 more meters (52 feet) to reach the crater ledge.

  20. Meteor orbit determination with improved accuracy

    NASA Astrophysics Data System (ADS)

    Dmitriev, Vasily; Lupovla, Valery; Gritsevich, Maria

    2015-08-01

    Modern observational techniques make it possible to retrive meteor trajectory and its velocity with high accuracy. There has been a rapid rise in high quality observational data accumulating yearly. This fact creates new challenges for solving the problem of meteor orbit determination. Currently, traditional technique based on including corrections to zenith distance and apparent velocity using well-known Schiaparelli formula is widely used. Alternative approach relies on meteoroid trajectory correction using numerical integration of equation of motion (Clark & Wiegert, 2011; Zuluaga et al., 2013). In our work we suggest technique of meteor orbit determination based on strict coordinate transformation and integration of differential equation of motion. We demonstrate advantage of this method in comparison with traditional technique. We provide results of calculations by different methods for real, recently occurred fireballs, as well as for simulated cases with a priori known retrieval parameters. Simulated data were used to demonstrate the condition, when application of more complex technique is necessary. It was found, that for several low velocity meteoroids application of traditional technique may lead to dramatically delusion of orbit precision (first of all, due to errors in Ω, because this parameter has a highest potential accuracy). Our results are complemented by analysis of sources of perturbations allowing to quantitatively indicate which factors have to be considered in orbit determination. In addition, the developed method includes analysis of observational error propagation based on strict covariance transition, which is also presented.Acknowledgements. This work was carried out at MIIGAiK and supported by the Russian Science Foundation, project No. 14-22-00197.References:Clark, D. L., & Wiegert, P. A. (2011). A numerical comparison with the Ceplecha analytical meteoroid orbit determination method. Meteoritics & Planetary Science, 46(8), pp. 1217

  1. A Global Model of Meteoric Sodium

    NASA Technical Reports Server (NTRS)

    Marsh, Daniel R.; Janches, Diego; Feng, Wuhu; Plane, John M. C.

    2013-01-01

    A global model of sodium in the mesosphere and lower thermosphere has been developed within the framework of the National Center for Atmospheric Research's Whole Atmosphere Community Climate Model (WACCM). The standard fully interactive WACCM chemistry module has been augmented with a chemistry scheme that includes nine neutral and ionized sodium species. Meteoric ablation provides the source of sodium in the model and is represented as a combination of a meteoroid input function (MIF) and a parameterized ablation model. The MIF provides the seasonally and latitudinally varying meteoric flux which is modeled taking into consideration the astronomical origins of sporadic meteors and considers variations in particle entry angle, velocity, mass, and the differential ablation of the chemical constituents. WACCM simulations show large variations in the sodium constituents over time scales from days to months. Seasonality of sodium constituents is strongly affected by variations in the MIF and transport via the mean meridional wind. In particular, the summer to winter hemisphere flow leads to the highest sodium species concentrations and loss rates occurring over the winter pole. In the Northern Hemisphere, this winter maximum can be dramatically affected by stratospheric sudden warmings. Simulations of the January 2009 major warming event show that it caused a short-term decrease in the sodium column over the polar cap that was followed by a factor of 3 increase in the following weeks. Overall, the modeled distribution of atomic sodium in WACCM agrees well with both ground-based and satellite observations. Given the strong sensitivity of the sodium layer to dynamical motions, reproducing its variability provides a stringent test of global models and should help to constrain key atmospheric variables in this poorly sampled region of the atmosphere.

  2. Arizona land use experiment

    NASA Technical Reports Server (NTRS)

    Winikka, C. C.; Schumann, H. H.

    1975-01-01

    Utilization of new sources of statewide remote sensing data, taken from high-altitude aircraft and from spacecraft is discussed along with incorporation of information extracted from these sources into on-going land and resources management programs in Arizona. Statewide cartographic applications of remote sensor data taken by NASA high-altitude aircraft include the development of a statewide semi-analytic control network, the production of nearly 1900 orthophotoquads (image maps) that are coincident in scale and area with the U.S. Geological Survey (USGS) 7. 5 minute topographic quadrangle map series, and satellite image maps of Arizona produced from LANDSAt multispectral scanner imagery. These cartographic products are utilized for a wide variety of experimental and operational earth resources applications. Applications of the imagery, image maps, and derived information discussed include: soils and geologic mapping projects, water resources investigations, land use inventories, environmental impact studies, highway route locations and mapping, vegetation cover mapping, wildlife habitat studies, power plant siting studies, statewide delineation of irrigation cropland, position determination of drilling sites, pictorial geographic bases for thematic mapping, and court exhibits.

  3. Meteor Beliefs Project: some meteoric imagery in the works of William Shakespeare

    NASA Astrophysics Data System (ADS)

    McBeath, A.; Gheorghe, A. D.

    2003-08-01

    Passages from three of William Shakespeare's plays are presented, illustrating some of the beliefs in meteors in 16th-17th century England. They also reflect earlier beliefs and information which it is known Shakespeare drew on in constructing his works.

  4. Present State and Prospects for the Meteor Research in Ukraine

    NASA Astrophysics Data System (ADS)

    Shulga, O.; Voloshchuk, Y.; Kolomiyets, S.; Cherkas, Y.; Kimakovskay, I.; Kimakovsky, S.; Knyazkova, E.; Kozyryev, Y.; Sybiryakova, Y.; Gorbanev, Y.; Stogneeva, I.; Shestopalov, V.; Kozak, P.; Rozhilo, O.; Taranukha, Y.

    2015-03-01

    ODESSA. Systematical study of the meteor events are being carried out since 1953. In 2003 complete modernization of the observing technique was performed, and TV gmeteor patrolh on the base of WATEC LCL902 cameras was created. @ wide variety of mounts and objectives are used: from Schmidt telescope F = 540 mm, F/D = 2.25 (field of view FOV = (0.68x0.51) deg, star limiting magnitude SLM = 13.5 mag, star astrometric accuracy 1-2 arcsec) up to Fisheye lenses F = 8 mm, F/D = 3.5 (FOV = (36x49) deg, SLM = 7 mag). The database of observations that was collected between 2003 and 2012 consists of 6176 registered meteor events. Observational programs on basis and non-basis observations in Odessa (Kryzhanovka station) and Zmeiny island are presented. Software suite of 12 programs was created for processing of meteor TV observations. It enables one to carry out the whole cycle of data processing: from image preprocessing up to orbital elements determination. Major meteor particles research directions: statistic, areas of streams, precise stream radiant, orbit elements, phenomena physics, flare appearance, wakes, afterglow, chemistry and density. KYIV. The group of meteor investigations has been functioning more than twenty years. The observations are carried out simultaneously from two points placed at the distance of 54 km. Super-isocon low light camera tubes are used with photo lens: F = 50mm, F/D = 1.5 (FOV = (23.5 x 19.0) deg, SLM = 9.5 mag), or F = 85, F/D = 1.5 (FOV = (13x11) deg, SLM = 11.5 mag). Astrometry, photometry, calculation of meteor trajectory in Earth atmosphere and computation of heliocentric orbit are realized in developed gFalling Starh software. KHARKOV. Meteor radio-observations have begun in 1957. In 1972, the radiolocation system MARS designed for automatic meteor registration was recognized as being the most sensitive system in the world. With the help of this system 250 000 faint meteors (up to 12 mag) were registered between 1972 and 1978 (frequency

  5. Ecoregions of Arizona (poster)

    USGS Publications Warehouse

    Griffith, Glenn E.; Omernik, James M.; Johnson, Colleen Burch; Turner, Dale S.

    2014-01-01

    Ecoregions denote areas of general similarity in ecosystems and in the type, quality, and quantity of environmental resources; they are designed to serve as a spatial framework for the research, assessment, management, and monitoring of ecosystems and ecosystem components. By recognizing the spatial differences in the capacities and potentials of ecosystems, ecoregions stratify the environment by its probable response to disturbance. These general purpose regions are critical for structuring and implementing ecosystem management strategies across federal agencies, state agencies, and nongovernment organizations that are responsible for different types of resources within the same geographical areas. The Arizona ecoregion map was compiled at a scale of 1:250,000. It revises and subdivides an earlier national ecoregion map that was originally compiled at a smaller scale. The approach used to compile this map is based on the premise that ecological regions can be identified through the analysis of the spatial patterns and the composition of biotic and abiotic phenomena that affect or reflect differences in ecosystem quality and integrity. These phenomena include geology, physiography, vegetation, climate, soils, land use, wildlife, and hydrology. The relative importance of each characteristic varies from one ecological region to another regardless of the hierarchical level. A Roman numeral hierarchical scheme has been adopted for different levels of ecological regions. Level I is the coarsest level, dividing North America into 15 ecological regions. Level II divides the continent into 50 regions. At level III, the continental United States contains 105 ecoregions and the conterminous United States has 85 ecoregions. Level IV is a further subdivision of level III ecoregions. Arizona contains arid deserts and canyonlands, semiarid shrub- and grass-covered plains, woodland- and shrubland-covered hills, lava fields and volcanic plateaus, forested mountains, glaciated

  6. Analysis of photometric spectra of 17 meteors

    NASA Technical Reports Server (NTRS)

    Millman, P. M.

    1982-01-01

    The initial phase of the photometry which involved 17 meteor spectra consisting of eight Geminid spectra, six Orionid spectra and three Eta Aquarid spectra is discussed. Among these 17 spectra it is found that the Geminid spectra are of the best quality and are used for the identification of the atomic lines and molecular bands that normally appear on video tape spectra. The data from the Geminid records are used for developing calibration techniques in photometry. The Orionid and Eta Aquarid spectra are chosen for early analysis because of the current interest in all physical and chemical data relating to Comet Halley.

  7. Arizona's Youth--Arizona's Jobs. An Introduction to School-to-Work Transitions in Arizona.

    ERIC Educational Resources Information Center

    Vandegrift, Judith A.; And Others

    This report provides a formative analysis of youth demographics and employment and training issues in the state of Arizona. The report clarifies issues of workforce supply and demand--as they pertain specifically to Arizona's youth--and explores the match between work force demand and training programs. It is based on information gathered and…

  8. The Southern Argentina Agile Meteor Radar (SAAMER): Platform for comprehensive meteor radar observations and studies

    NASA Astrophysics Data System (ADS)

    Janches, D.; Hormaechea, J.; Pifko, S.; Hocking, W.; Fritts, D.; Brunini, C.; Close, S.; Michell, R.; Samara, M.

    2014-07-01

    The Southern Argentina Agile Meteor Radar (SAAMER) is a new generation system deployed in Rio Grande, Tierra del Fuego, Argentina (53^oS) in May 2008 (Janches et al., 2013,2014). SAAMER transmits 10 times more power than regular meteor radars, and uses a newly developed transmitting array, which focuses power upward instead of the traditional single-antenna-all-sky configuration. The system is configured such that the transmitter array can also be utilized as a receiver. The new design greatly increases the sensitivity of the radar enabling the detection of large numbers of particles at low zenith angles. The more concentrated transmitted power enables additional meteor studies besides those typical of these systems based on the detection of specular reflections, such as routine detections of head echoes and non-specular trails, previously only possible with High Power and Large Aperture radars (Janches et al., 2014). In August 2010, SAAMER was upgraded to a system capable to determine meteoroid orbital parameters. This was achieved by adding two remote receiving stations approximately 10 km away from the main site in near perpendicular directions (Pifko et al., 2014). The upgrade significantly expands the science that is achieved with this new radar enabling us to study the orbital properties of the interplanetary dust environment. Because of the unique geographical location, the SAAMER allows for additional inter-hemispheric comparison with measurements from Canadian Meteor Orbit Radar, which is geographically conjugate. Initial surveys show, for example, that SAAMER observes a very strong contribution of the South Toroidal Sporadic meteor source (Pifko et al., 2014), of which limited observational data is available. In addition, SAAMER offers similar unique capabilities for meteor showers and streams studies given the range of ecliptic latitudes that the system enables to survey (Janches et al., 2013). It can effectively observe radiants from the ecliptic south

  9. Rover Tracks at Crater's Edge

    NASA Technical Reports Server (NTRS)

    2007-01-01

    Tracks left by NASA's Mars Exploration Rover Opportunity as it traveled along the rim of Victoria Crater can be seen clearly in this image taken by the High Resolution Imaging Science Experiment (HiRISE) camera on NASA's Mars Reconnaissance Orbiter spacecraft.

    This is a subframe of a larger image that the camera acquired on June 26, 2007. The larger image will be released as HiRISE catalogue number PSP_004289_1780 after geometric processing.

    Opportunity first approached Victoria Crater at an alcove informally named 'Duck Bay' (see tracks at left). It then drove along the crater's sinuous edge in a clockwise direction before heading back to Duck Bay, where it is expected to enter the crater in early July 2007.

  10. LRO/LOLA - Counting Craters

    NASA Video Gallery

    Using the Lunar Reconnaissance Orbiter’s Lunar Orbiter Laser Altimeter (LOLA), NASA scientists have created the first-ever comprehensive catalog of large craters on the moon. In this animation, lun...

  11. Hourly Illumination of Shackleton Crater

    NASA Video Gallery

    Illumination of Shackleton crater, a 21-km-diameter (12.5 mile-diameter) structure situated adjacent to the Moon’s south pole. The resolution is 30 meters (approximately 100 feet) per pixel. Fra...

  12. Psychedelic Crater Rim

    NASA Technical Reports Server (NTRS)

    2004-01-01

    Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  13. Crater Floor in Color

    NASA Technical Reports Server (NTRS)

    2004-01-01

    Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  14. Degradation of Victoria Crater, Mars

    NASA Technical Reports Server (NTRS)

    Wilson, Sharon A.; Grant, John A.; Cohen, Barbara A.; Golombek, Mathew P.; Geissler, Paul E.; Sullivan, Robert J.; Kirk, Randolph L.; Parker, Timothy J.

    2008-01-01

    The $\\sim$750 m diameter and $\\sim$75 m deep Victoria crater in Meridiani Planum, Mars, presents evidence for significant degradation including a low, serrated, raised rim characterized by alternating alcoves and promontories, a surrounding low relief annulus, and a floor partially covered by dunes. The amount and processes of degradation responsible for the modified appearance of Victoria crater were evaluated using images obtained in situ by the Mars Exploration Rover Opportunity in concert with a digital elevation model created using orbital HiRISE images. Opportunity traversed along the north and northwest rim and annulus, but sufficiently characterized features visible in the DEM to enable detailed measurements of rim relief, ejecta thickness, and wall slopes around the entire degraded, primary impact structure. Victoria retains a 5 m raised rim consisting of 1-2 m of uplifted rocks overlain by 3 m of ejecta at the rim crest. The rim is $\\sim$120 to 220 m wide and is surrounded by a dark annulus reaching an average of 590 m beyond the raised rim. Comparison between observed morphology and that expected for pristine craters 500 to 750 m across indicate the original, pristine crater was close to 600 m in diameter. Hence, the crater has been erosionally widened by approximately 150 m and infilled by about 50 m of sediments. Eolian processes are responsible for modification at Victoria, but lesser contributions from mass wasting or other processes cannot be ruled out. Erosion by prevailing winds is most significant along the exposed rim and upper walls and accounts for $\\sim$50 m widening across a WNW-ESE diameter. The volume of material eroded from the crater walls and rim is $\\sim$20% less than the volume of sediments partially filling the crater, indicating eolian infilling from sources outside the crater over time. The annulus formed when $\\sim$1 m deflation of the ejecta created a lag of more resistant hematite spherules that trapped darker, regional

  15. Limb of Copernicus Impact Crater

    NASA Technical Reports Server (NTRS)

    1991-01-01

    Copernicus is 93 km wide and is located within the Mare Imbrium Basin, northern nearside of the Moon (10 degrees N., 20 degrees W.). Image shows crater floor, floor mounds, rim, and rayed ejecta. Rays from the ejecta are superposed on all other surrounding terrains which places the crater in its namesake age group: the Copernican system, established as the youngest assemblage of rocks on the Moon (Shoemaker and Hackman, 1962, The Moon: London, Academic Press, p.289- 300).

  16. Impact cratering through geologic time

    USGS Publications Warehouse

    Shoemaker, E.M.; Shoemaker, C.S.

    1998-01-01

    New data on lunar craters and recent discoveries about craters on Earth permit a reassessment of the bombardment history of Earth over the last 3.2 billion years. The combined lunar and terrestrial crater records suggest that the long-term average rate of production of craters larger than 20 km in diameter has increased, perhaps by as much as 60%, in the last 100 to 200 million years. Production of craters larger than 70 km in diameter may have increased, in the same time interval, by a factor of five or more over the average for the preceding three billion years. A large increase in the flux of long-period comets appears to be the most likely explanation for such a long-term increase in the cratering rate. Two large craters, in particular, appear to be associated with a comet shower that occurred about 35.5 million years ago. The infall of cosmic dust, as traced by 3He in deep sea sediments, and the ages of large craters, impact glass horizons, and other stratigraphic markers of large impacts seem to be approximately correlated with the estimated times of passage of the Sun through the galactic plane, at least for the last 65 million years. Those are predicted times for an increased near-Earth flux of comets from the Oort Cloud induced by the combined effects of galactic tidal perturbations and encounters of the Sun with passing stars. Long-term changes in the average comet flux may be related to changes in the amplitude of the z-motion of the Sun perpendicular to the galactic plane or to stripping of the outer Oort cloud by encounters with large passing stars, followed by restoration from the inner Oort cloud reservoir.

  17. Technology Transfer and Economic Development in Arizona.

    ERIC Educational Resources Information Center

    Brophy, James

    The status of Arizona's effort to encourage the creation and expansion of high technology based on the discoveries and new knowledge developed at its research universities is discussed. The study of the University of Arizona and Arizona State University was recommended by the Arizona Board of Regents' Task Force on Excellence, Efficiency and…

  18. Geology of Lofn Crater, Callisto

    NASA Technical Reports Server (NTRS)

    Greeley, Ronald; Heiner, Sarah; Klemaszewski, James E.

    2001-01-01

    Lofn crater is a 180-km-diameter impact structure in the southern cratered plains of Callisto and is among the youngest features seen on the surface. The Lofn area was imaged by the Galileo spacecraft at regional-scale resolutions (875 m/pixel), which enable the general geology to be investigated. The morphology of Lofn crater suggests that (1) it is a class of impact structure intermediate between complex craters and palimpsests or (2) it formed by the impact of a projectile which fragmented before reaching the surface, resulting in a shallow crater (even for Callisto). The asymmetric pattern of the rim and ejecta deposits suggests that the impactor entered at a low angle from the northwest. The albedo and other characteristics of the ejecta deposits from Lofn also provide insight into the properties of the icy lithosphere and subsurface configuration at the time of impact. The "target" for the Lofn impact is inferred to have included layered materials associated with the Adlinda multiring structure northwest of Loh and ejecta deposits from the Heimdall crater area to the southeast. The Lofn impact might have penetrated through these materials into a viscous substrate of ductile ice or possibly liquid water. This interpretation is consistent with models of the current interior of Callisto based on geophysical information obtained from the Galileo spacecraft.

  19. Distant Secondary Craters from Lyot Crater, Mars, and Implications for Ages of Planetary Bodies

    NASA Astrophysics Data System (ADS)

    Robbins, S. J.; Hynek, B. M.

    2011-03-01

    We identified thousands of secondary craters in distinct clusters up to 5200 km from their primary crater, Lyot, on Mars. Their properties, relation to Lyot, and broader implications to secondary cratering and planetary ages will be discussed.

  20. Very Precise Orbits of 1998 Leonid Meteors

    NASA Technical Reports Server (NTRS)

    Betlem, Hans; Jenniskens, Peter; vantLeven, Jaap; terKuile, Casper; Johannink, Carl; Zhao, Hai-Bin; Lei, Chen-Ming; Li, Guan-You; Zhu, Jin; Evans, Steve; DeVincenzi, Donald L. (Technical Monitor)

    1999-01-01

    Seventy-five orbits of Leonid meteors obtained during the 1998 outburst are presented. Thirty-eight are precise enough to recognize significant dispersion in orbital elements. Results from the nights of 1998 November 16/17 and 17/18 differ, in agreement with the dominant presence of different dust components. The shower rate profile of 1998 November 16/17 was dominated by a broad component, rich in bright meteors. The radiant distribution is compact. The semimajor axis is confined to values close to that of the parent comet, whereas the distribution of inclination has a central condensation in a narrow range. On the other hand, 1998 November 17/18 was dominated by dust responsible for a more narrow secondary peak in the flux curve. The declination of the radiant and the inclination of the orbit are more widely dispersed. The argument of perihelion, inclination, and the perihelion distance are displaced. These data substantiate the hypothesis that trapping in orbital resonances is important for the dynamical evolution of the broad component.

  1. Meteoric Magnesium Ions in the Martian Atmosphere

    NASA Technical Reports Server (NTRS)

    Pesnell, William Dean; Grebowsky, Joseph

    1999-01-01

    From a thorough modeling of the altitude profile of meteoritic ionization in the Martian atmosphere we deduce that a persistent layer of magnesium ions should exist around an altitude of 70 km. Based on current estimates of the meteoroid mass flux density, a peak ion density of about 10(exp 4) ions/cm is predicted. Allowing for the uncertainties in all of the model parameters, this value is probably within an order of magnitude of the correct density. Of these parameters, the peak density is most sensitive to the meteoroid mass flux density which directly determines the ablated line density into a source function for Mg. Unlike the terrestrial case, where the metallic ion production is dominated by charge-exchange of the deposited neutral Mg with the ambient ions, Mg+ in the Martian atmosphere is produced predominantly by photoionization. The low ultraviolet absorption of the Martian atmosphere makes Mars an excellent laboratory in which to study meteoric ablation. Resonance lines not seen in the spectra of terrestrial meteors may be visible to a surface observatory in the Martian highlands.

  2. The Taurid complex meteor showers and asteroids

    NASA Astrophysics Data System (ADS)

    Porubčan, V.; Kornoš, L.; Williams, I. P.

    2006-06-01

    The structure of the Taurid meteor complex based on photographic orbits available in the IAU Meteor database is studied. We have searched for potential sub-streams or filaments to be associated with the complex utilizing the Southworth-Hawkins D-criterion. Applying a strict limiting value for D=0.10, fifteen sub-streams or filaments, consisting of more than three members, could be separated out from the general complex. To confirm their mutual consistence as filaments, rather than fortuitous clumping at the present time, the orbital evolution over 5000 years of each member is studied. Utilizing the D-criterion we also searched for NEOs that might be associated with the streams and filaments of the complex and investigated the orbital evolution of potential members. Possible associations between 7 Taurid filaments and 9 NEOs were found. The most probable are for S Psc(b) -- 2003QC10, N Tau(a) -- 2004TG10, ο Ori -- 2003UL3 and N Tau(b) -- 2002XM35. Some of the potential parent objects could be either dormant comets or larger boulders moving within the complex. Three of the most populated filaments of the complex may have originated from 2P/Encke.

  3. Positional Measurements of the Meteor TV Images

    NASA Astrophysics Data System (ADS)

    Gorbanev, Yu. M.; Kimakovsky, S. R.; Knyazkova, E. F.

    We discuss the methods and software which is used for processing of the meteor TV images. Methods are based on the principles of the aperture CCD photometry. Software enables one to make processing of the observational material that was secured using TV methods with telescopic systems (field of view less that 1 angular degree), as well as with astrocameras of the wide field of view (field of view less 2-4 angular degrees, and even more than 50 degrees). We also elaborated method that allows one to identify operatively and to measure automatically rectangular coordinates within the image frame, as well as to calculate equatorial coordinates of the object using the Turner method and compiled stellar catalogues. This method was tested with observational material obtained with the help of TV meteor patrol within the period from 2003 to 2010 at Kryzhanovka station that belongs to Astronomical Observatory of Odessa National University. We performed an analysis of accuracy determination of the stellar images measurements. Software was tested in order to use it for the comet observations.

  4. Gasdynamic substantiation of physical theory of meteors

    NASA Astrophysics Data System (ADS)

    Egorova, Lidia A.; Tirskiy, Grigoriy A.

    2014-12-01

    Physical theory of meteors developing since 30s of the last century, based on two ordinary differential equations: the equation of motion for the center of mass of meteoroid and equation of meteoroid ablation. These equations contain drag and heat transfer coefficients, which are share of momentum and energy transferred from gas to meteoroid and effective enthalpy of mass loss. Accounting for different values of these coefficients substantially changes meteoroid ballistics compared with the results of simple physical theory of meteors. For the drag coefficient a simple interpolation formula is valid for all flow regimes and depends on the Reynolds number. The heat transfer coefficient represented in the form of the approximation depending on density and meteoroid radius. Based on the law of conservation of mass and energy at the front of meteoroid melting and evaporation the explicit expression for the effective enthalpy of mass loss Q was obtained, depending on the speed of the meteoroid and heterogeneous reactions on the surface. Classical solution gives a significant deviation from the exact one obtained in present study for small bodies (1 mm) at high altitudes and high speeds.

  5. Results of the IMO Video Meteor Network - January 2014

    NASA Astrophysics Data System (ADS)

    Molau, Sirko; Kac, Javor; Crivello, Stefano; Stomeo, Enrico; Barentsen, Geert; Goncalves, Rui

    2014-04-01

    The 2014 January results of the IMO Video Meteor Network are presented, based on more than 18 000 meteors collected in almost 6 000 hours of observing time. Flux density profile of the Quadrantids around the maximum (January 3/4) is presented and a population index of r=1.8 is obtained for the night of maximum.

  6. Results of the IMO Video Meteor Network - June 2014

    NASA Astrophysics Data System (ADS)

    Molau, Sirko; Kac, Javor; Crivello, Stefano; Stomeo, Enrico; Barentsen, Geert; Goncalves, Rui; Igaz, Antal

    2014-10-01

    About 18 500 meteors were recorded in almost 6 500 hours of effective observing time by 78 cameras of the IMO Video Meteor Network in 2014 June. Activity of the Daytime Arietids was studied and the first attempt to calculate the flux density profile is presented.

  7. The 2011 Draconids: The First European Airborne Meteor Observation Campaign

    NASA Astrophysics Data System (ADS)

    Vaubaillon, Jeremie; Koten, Pavel; Margonis, Anastasios; Toth, Juraj; Rudawska, Regina; Gritsevich, Maria; Zender, Joe; McAuliffe, Jonathan; Pautet, Pierre-Dominique; Jenniskens, Peter; Koschny, Detlef; Colas, Francois; Bouley, Sylvain; Maquet, Lucie; Leroy, Arnaud; Lecacheux, Jean; Borovicka, Jiri; Watanabe, Junichi; Oberst, Jürgen

    2015-02-01

    On 8 October 2011, the Draconid meteor shower (IAU, DRA) was predicted to cause two brief outbursts of meteors, visible from locations in Europe. For the first time, a European airborne meteor observation campaign was organized, supported by ground-based observations. Two aircraft were deployed from Kiruna, Sweden, carrying six scientists, 19 cameras and eight crew members. The flight geometry was chosen such that it was possible to obtain double-station observations of many meteors. The instrument setup on the aircraft as well as on the ground is described in full detail. The main peak from 1900-dust ejecta happened at the predicted time and at the predicted rate. The second peak was observed from the earlier flight and from the ground, and was caused most likely by trails ejected in the nineteenth century. A total of 250 meteors were observed, for which light curve data were derived. The trajectory, velocity, deceleration and orbit of 35 double station meteors were measured. The magnitude distribution index was high, as a result of which there was no excess of meteors near the horizon. The light curve proved to be extremely flat on average, which was unexpected. Observations of spectra allowed us to derive the compositional information of the Draconids meteoroids and showed an early release of sodium, usually interpreted as resulting from fragile meteoroids. Lessons learned from this experience are derived for future airborne meteor shower observation campaigns.

  8. Goals, technique and equipment of meteor study in Russia

    NASA Astrophysics Data System (ADS)

    Kartashova, A.; Bagrov, A. V.; Bolgova, G. T.; Kruchkov, S. V.; Leonov, V. A.; Mazurov, V. A.

    2013-09-01

    Institute of Astronomy RAS is one of the science institutes in the Russian Federation providing systematic optical meteor observations and supervises several meteor groups in our country. The main tasks of our investigations are dedicated to study meteoroid nature as well as meteoroid streams and meteoroid population in the Solar System. In the XXI century we in Russia carry out the reconstruction of our meteor astronomy due to possibilities of new meteor observation equipment (more powerful than were used before as visual and photographic methods) had made possible to select more interesting goals. First of our task is investigation of meteoroid streams crossing the Earth's orbit, and character of meteoroid distributions along of them. The multi stations meteor monitoring from located in the both hemispheres of the Earth can help in this study. According to the analysis of the evolution of meteor orbits, the compact and long lived meteoroid streams consist mainly from large particles. The observation equipment (cheap TV-cameras) with low limiting magnitude we use for gathering observational data. On the other hand, the observations of weak meteors are needed for new meteor shower indication (or confirmation of known meteor shower). The more effective way to do it is comparison of individual meteor orbits parameters (then calculation of radiants of meteor showers). The observations of space debris (as the meteors with low velocity - less 11.2 km/s) can be taking up within this task. The combination of high sensitive TV-cameras WATEC and super-fast lenses COMPUTAR are widely used for meteor TV-monitoring. The TVsystems for round-year meteor observations are fixed and are permanently oriented to the zenith area (the patrol camera - PatrolCa). The mobile TV-cameras (MobileCa) are used for double station observations (if it is possible) and located not far from main cameras PatrolCa (20-30 km). The mobile TVcameras observe 90% of main PatrolCa cameras FOV at altitudes

  9. Meteor trails observed by the Sloan Digital Sky Survey

    NASA Astrophysics Data System (ADS)

    Cikota, A.; Bektešević, D.; Cikota, S.; Weaver, B.; Jevremović, D.; Vinković, D.

    2014-07-01

    Scientific observation of meteors is not simple because they have large angular size and random appearance in time and position on the sky. Bright meteors can be easily observed by naked eye or by video cameras in low resolution, but the luminosity distribution of meteors at their fainter end, the actual column diameter of the radiating zone, meteor fragmentation and the microstructure of lightcurves (especially when a meteor is detected through several color filters, as it happened in SDSS) is not well investigated. However, wide-field surveys, such as SDSS or the future LSST, with long time coverage over a significant fraction of sky might be helpful in collecting a scientifically relevant sample of low-brightness meteors. We used a custom designed Python script to detect linear features in SDSS images. The detection is performed in two steps: 1) we detect stars with Source Extractor [1] and blend them out; 2) we define a threshold so as to analyze 10000 points over the threshold; 3) we apply RANSAC [2] to detect points forming a line. We detected trails in over 15000 calibrated and sky-subtracted ''frame'' images in two filters so far. The drift scan in imaging survey mode of SDSS enables simple distinction between "apparently fast" meteors and other "slow" linear features caused by satellites and space debris, so that around 4000 frames could be eliminated as obvious satellites. Here we discuss the detection method, show some interesting preliminary results of the analysis of detected meteors, and discuss implications for other surveys.

  10. Comets and meteors in the beliefs of ancient mayas

    NASA Astrophysics Data System (ADS)

    Yershova, G. G.

    2001-12-01

    Data concerning the Mayan approach to comets and meteors have till now been available mostly from ethnographical and folklore sources which dealt, as a rule, with various beliefs and tokens. The studies of hieroglyphic texts of the Classic Period (AD 600-900) have proved that comets and meteors were undoubtedly known in this culture through astronomical observations and their periodicity.

  11. Romanian Observational Campaign on Summer Meteor Showers in 2000

    NASA Astrophysics Data System (ADS)

    Berinde, S.; Grigore, V.

    2001-01-01

    In this paper we summarize the most important results of a summer observational campaign dedicated to the observation of the entire spectrum of active meteor showers on this period. Our results are enriched by the determination of two possible new radiants in Cygnus, not related to any other known meteor shower.

  12. Meteor Showers of the Earth-crossing Asteroids

    NASA Astrophysics Data System (ADS)

    Pulat, Babadzhanov; Gulchekhra, Kokhirova

    2015-03-01

    The results of search for meteor showers associated with the asteroids crossing the Earthfs orbit and moving on comet-like orbits are given. It was shown that among 2872 asteroids discovered till 1.01.2005 and belonging to the Apollo and Amor groups, 130 asteroids have associated meteor showers and, therefore, are the extinct cometary nuclei.

  13. First 3-D simulations of meteor plasma dynamics and turbulence

    NASA Astrophysics Data System (ADS)

    Oppenheim, Meers M.; Dimant, Yakov S.

    2015-02-01

    Millions of small but detectable meteors hit the Earth's atmosphere every second, creating trails of hot plasma that turbulently diffuse into the background atmosphere. For over 60 years, radars have detected meteor plasmas and used these signals to infer characteristics of the meteoroid population and upper atmosphere, but, despite the importance of meteor radar measurements, the complex processes by which these plasmas evolve have never been thoroughly explained or modeled. In this paper, we present the first fully 3-D simulations of meteor evolution, showing meteor plasmas developing instabilities, becoming turbulent, and inhomogeneously diffusing into the background ionosphere. These instabilities explain the characteristics and strength of many radar observations, in particular the high-resolution nonspecular echoes made by large radars. The simulations reveal how meteors create strong electric fields that dig out deep plasma channels along the Earth's magnetic fields. They also allow researchers to explore the impacts of the intense winds and wind shears, commonly found at these altitudes, on meteor plasma evolution. This study will allow the development of more sophisticated models of meteor radar signals, enabling the extraction of detailed information about the properties of meteoroid particles and the atmosphere.

  14. Investigation of meteor shower parent bodies using various metrics

    NASA Astrophysics Data System (ADS)

    Dumitru, B. A.; Birlan, M.; Nedelcu, A.; Popescu, M.

    2016-01-01

    The present knowledge of meteor showers identifies the small bodies of our Solar System as supply sources for meteor streams. Both comets and asteroids are considered as the origin of meteor showers. The new paradigm of "active asteroids" opens up a large field of investigation regarding the relationships between asteroids and meteors. Processes like ejection and disaggregation at impacts, rotational instabilities, electrostatic repulsion, radiation pressure, dehydration stress followed by thermal fractures, sublimation of ices are sources of matter loss from asteroids. Our objective is to find genetic relationships between asteroids and meteor showers using metrics based on orbital elements. For this objective we selected three metrics (Southworth and Hawkins, 1963; Asher et al. 1993, and Jopek, 1993, respectively), the recent MPC database and the more recent IAU meteor shower database. From our analysis, 41 of the meteor showers have probabilities of being produced (or to be fueled) by asteroids. Our sample of asteroids contains more than 1000 objects, all of them belonging to the Near-Earth Asteroid population. The systematic approach performed, based on the physical properties of our sample, reinforced the link between asteroids and their associated meteor shower.

  15. Reuyl Crater Dust Avalanches

    NASA Technical Reports Server (NTRS)

    2002-01-01

    (Released 13 May 2002) The Science The rugged, arcuate rim of the 90 km crater Reuyl dominates this THEMIS image. Reuyl crater is at the southern edge of a region known to be blanketed in thick dust based on its high albedo (brightness) and low thermal inertia values. This thick mantle of dust creates the appearance of snow covered mountains in the image. Like snow accumulation on Earth, Martian dust can become so thick that it eventually slides down the face of steep slopes, creating runaway avalanches of dust. In the center of this image about 1/3 of the way down is evidence of this phenomenon. A few dozen dark streaks can be seen on the bright, sunlit slopes of the crater rim. The narrow streaks extend downslope following the local topography in a manner very similar to snow avalanches on Earth. But unlike their terrestrial counterparts, no accumulation occurs at the bottom. The dust particles are so small that they are easily launched into the thin atmosphere where they remain suspended and ultimately blow away. The apparent darkness of the avalanche scars is due to the presence of relatively dark underlying material that becomes exposed following the passage of the avalanche. Over time, new dust deposition occurs, brightening the scars until they fade into the background. Although dark slope streaks had been observed in Viking mission images, a clear understanding of this dynamic phenomenon wasn't possible until the much higher resolution images from the Mars Global Surveyor MOC camera revealed the details. MOC images also showed that new avalanches have occurred during the time MGS has been in orbit. THEMIS images will allow additional mapping of their distribution and frequency, contributing new insights about Martian dust avalanches. The Story The stiff peaks in this image might remind you of the Alps here on Earth, but they really outline the choppy edge of a large Martian crater over 50 miles wide (seen in the context image at right). While these aren

  16. THE RETURN OF THE ANDROMEDIDS METEOR SHOWER

    SciTech Connect

    Wiegert, Paul A.; Brown, Peter G.; Weryk, Robert J.; Wong, Daniel K.

    2013-03-15

    The Andromedid meteor shower underwent spectacular outbursts in 1872 and 1885, producing thousands of visual meteors per hour and described as ''stars fell like rain'' in Chinese records of the time. The shower originates from comet 3D/Biela whose disintegration in the mid-1800's is linked to the outbursts, but the shower has been weak or absent since the late 19th century. This shower returned in 2011 December with a zenithal hourly rate of approximately 50, the strongest return in over a hundred years. Some 122 probable Andromedid orbits were detected by the Canadian Meteor Orbit Radar while one possible brighter Andromedid member was detected by the Southern Ontario Meteor Network and several single station possible Andromedids by the Canadian Automated Meteor Observatory. The shower outburst occurred during 2011 December 3-5. The radiant at R.A. +18 Degree-Sign and decl. +56 Degree-Sign is typical of the ''classical'' Andromedids of the early 1800s, whose radiant was actually in Cassiopeia. Numerical simulations of the shower were necessary to identify it with the Andromedids, as the observed radiant differs markedly from the current radiant associated with that shower. The shower's orbital elements indicate that the material involved was released before 3D/Biela's breakup prior to 1846. The observed shower in 2011 had a slow geocentric speed (V{sub G} = 16 km s{sup -1}) and was comprised of small particles: the mean measured mass from the radar is {approx}5 Multiplication-Sign 10{sup -7} kg, corresponding to radii of 0.5 mm at a bulk density of 1000 kg m{sup -3}. Numerical simulations of the parent comet indicate that the meteoroids of the 2011 return of the Andromedids shower were primarily ejected during 3D/Biela's 1649 perihelion passage. The orbital characteristics, radiant, and timing as well as the absence of large particles in the streamlet are all broadly consistent with simulations. However, simulations of the 1649 perihelion passage necessitate going

  17. High mobility of landslides on the Mercury crater rims

    NASA Astrophysics Data System (ADS)

    Fukuoka, H.; Kadota, N.; Kiritoshi, I.; Sugiyama, H.; Uragami, H.

    2013-12-01

    The NASA's MESSENGER mercury spacecraft was launched by NASA in 2004, and orbital insertion was successfully completed in 2011. Among its scientific instruments, the Mercury Dual Imaging System (MDIS) and the Mercury Laser Altimeter (MLA) are used to extract the mercury terrain topography. This mission revealed various features of the mercury topography with horizontal resolution of 1 km. Up to July 2013, elevation of the north hemisphere terrain had been released on the net (Quickmap: http://messenger-act.actgate.com/msgr_public_released/react_quickmap.html). As reported by previous studies on landslides found on the lunar crater rims (Fukuoka et al., 2011), they showed extremely small H/V = tan (apparent friction) of the movement, even though almost no groundwater could have been expected ever. Authors examined the crater rims in the northern hemisphere of latitude higher than 65 degrees, because the precision of the altitude is higher in the polar and equatorial regions. We found as many similar landslides along the crater rims. Then, in order to compare the mobility of landslides with lunar ones, we have examined the apparent friction (H/T). In most cases, the H/T values of those landslides are between 0.1 and 0.2, like long-runout landslides on the Moon, Mars and Earth. If the rocks on the mercury show the similar friction as rocks on the earth, those values should be higher than 0.5. Possible mechanism of the small H/L could be cumulated shear displacement induced by repeated quakes by meteor impact over billions of years and / or exotic mechanism including tectonic function.

  18. SUPERSTITION WILDERNESS, ARIZONA.

    USGS Publications Warehouse

    Peterson, Donald W.; Jinks, Jimmie E.

    1984-01-01

    On the basis of geologic studies and mineral evaluations most of the Superstition Wilderness and adjoining areas are judged to have little promise for occurrence of mineral resources. However, two areas in an east-trending zone near the southern margin of the area, marked by spotty occurrences of mineralized rock, prospect pits, and a band of geochemical anomalies that coincides with aligned magnetic anomalies, are considered to have probable mineral-resource potential. This zone lies within about 6 mi of two productive mines in Arizona's great copper belt, and the trend of the zone is parallel to many of the significant mineralized structures of this belt. A small isolated uranium anomaly was found in the northeastern part of the wilderness, but no evidence of other energy resources, such as petroleum, coal, or geothermal, was found.

  19. Superstition Wilderness, Arizona

    SciTech Connect

    Peterson, D.W.; Jinks, J.E.

    1984-01-01

    On the basis of geologic studies and mineral evaluations made between 1973 and 1977, most of the Superstition Wilderness and adjoining areas are judged to have little promise for occurrence of mineral resources. However, two areas in an east-trending zone near the southern margin of the area, marked by spotty occurrences of mineralized rock, prospect pits, and a band of geochemical anomalies that coincides with alined magnetic anomalies, are considered to have probable mineral-resource potential. This zone lies within about 6 mi of two productive mines in Arizona's great copper belt, and the trend of the zone is parallel to many of the significant mineralized structures of this belt. A small isolated uranium anomaly was found in the northeastern part of the wilderness, but no evidence of other energy resources, such as petroleum, coal, or geothermal, was found.

  20. Arizona Forest Fire

    NASA Technical Reports Server (NTRS)

    2001-01-01

    These ASTER images cover an area of 11 x 14 km on the north rim of the Grand Canyon, Arizona, and were acquired May 12, 2000. The left image displays bands 3,2,1 in RGB, displaying vegetation as red. The large dark area is burned forest, and small smoke plumes can be seen at the edges where active fires are burning. The right display substitutes SWIR band 8 for band 3. The bright red spots are the active fires, visible because the SWIR wavelength region has the capability to penetrate through the smoke. This image is located at 35.9 degrees north latitude and 113.4 degrees west longitude.

    The U.S. science team is located at NASA's Jet Propulsion Laboratory, Pasadena, Calif. The Terra mission is part of NASA's Science Mission Directorate.