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New Gullies on Martian Sand
…
| title |
New Gullies on Martian Sand Dune |
| description |
As part of extended-mission science investigation using the Mars Orbiter Camera on NASA's Mars Global Surveyor spacecraft, the camera team is re-imaging many locations where previous observations revealed gullies. The intent is to see if gully-forming processes are operating on Mars at the present time. The team has found one location where a new gully formed on a dune in an unnamed crater in the Hellespontus region of Mars, west of the Hellas Basin. This pair of narrow-angle images from the Mars Orbiter Camera shows the dune as it appeared on July 17, 2002, (left) and as it appeared on April 27, 2005, (right). The nearly three Earth years of intervening time amount to about 1.4 Mars years. During this period, a couple of gullies formed on the dune slip face. It is critical to recognize that the 2002 image was obtained at a time of year when the incident sunlight was coming in from a lower angle, relative to the horizon, than in the 2005 image. If the gullies had been present in 2002, their appearance would be sharper and more pronounced than they are in the 2005 image. The gullies simply did not exist on July 17, 2002. The steep walls of the gully alcove and channels suggests that the sand in this dune is somewhat cohesive, an observation common among martian sand dunes seen by the Mars Orbiter Camera over the past eight years. Image Credit: NASA/JPL/MSSS |
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Evidence of Martian Quakes
| title |
Evidence of Martian Quakes |
| description |
One of the many mysteries associated with martian geology is the origin of gullies found at latitudes poleward of 30 degrees latitude. Most of these gullies are found within craters or other depressions, and appear to be related to the bedrock. Several hypotheses have been proposed for their origin, including groundwater seepage and melting at the base of a dust-mantled snow pack. Some middle-latitude gullies are found on sand dunes. These gullies appear to be different from those found on the slopes of craters, but generally have been interpreted to form by similar processes. In the present martian environment, it is difficult to introduce water to the surface. The temperature and atmospheric pressure may permit water to exist, but the rate of heating of the ground and atmosphere, and the amount of energy available to warm the ground or melt snow, are not conducive to such processes. An alternative process of gully formation on these sand dunes involves frozen carbon dioxide trapped in the winter by windblown sand, then subliming rapidly enough for the escaping carbon-dioxide gas to make the sand flow as a gully-cutting fluid. As part of extended-mission science investigation using the Mars Orbiter Camera on NASA's Mars Global Surveyor spacecraft, the camera team is re-imaging many locations where previous observations revealed gullies. The intent is to see if gully-forming processes are operating on Mars at the present time. The team has found one location where a new gully formed on a dune in an unnamed crater in the Hellespontus region of Mars, west of the Hellas Basin. This pair of narrow-angle images from the Mars Orbiter Camera shows the dune as it appeared on July 17, 2002, (left) and as it appeared on April 27, 2005, (right). The nearly three Earth years of intervening time amount to about 1.4 Mars years. During this period, a couple of gullies formed on the dune slip face. It is critical to recognize that the 2002 image was obtained at a time of year when the incident sunlight was coming in from a lower angle, relative to the horizon, than in the 2005 image. If the gullies had been present in 2002, their appearance would be sharper and more pronounced than they are in the 2005 image. The gullies simply did not exist on July 17, 2002. The steep walls of the gully alcove and channels suggests that the sand in this dune is somewhat cohesive, an observation common among martian sand dunes seen by the Mars Orbiter Camera over the past eight years. Wider context for the dune is shown in a mosaic of two images from the Thermal Emission Imaging System on NASA's Mars Odyssey orbiter, encompassing the dark-toned sand dune field on the floor of a crater located near 49.8 degrees south latitude, 325.4 degrees west longitude. In this image, north is approximately up and sunlight illuminates the scene from the upper left. More information about this image can be found at: http://photojournal.jpl.nasa.gov/catalog/PIA04290 |
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Light Deposits Indicate Wate
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| Title |
Light Deposits Indicate Water Flowing on Mars |
| Explanation |
What's creating light-toned deposits on Mars? Quite possibly -- water! Images of the same parts of mid-latitude Mars [ http://antwrp.gsfc.nasa.gov/apod/ap010628.html ] taken over the years but released [ http://www.msss.com/mars_images/moc/2006/12/06/gullies/sirenum_crater/index.html ] only last week have shown unexpected new light-toned deposits where there were none before. One clear case is shown above [ http://photojournal.jpl.nasa.gov/catalog/PIA09028 ], where the same crater on Mars is shown as photographed in 1999 August and again in 2005 September. The unusual deposit is visible only on the more recent photograph. Apparent tributaries near the bottom bolster the leading hypothesis [ http://planetary.org/blog/article/00000789/ ] that water gushed out of the crater wall, flowed down the crater, and soon evaporated into the thin Martian atmosphere [ http://www.daviddarling.info/encyclopedia/M/Marsatmos.html ]. Although frozen water-ice [ http://antwrp.gsfc.nasa.gov/apod/ap050720.html ] has been known near the Martian poles [ http://antwrp.gsfc.nasa.gov/apod/ap981216.html ] for years, free flowing surface water like this was not expected to be seen in the mid-latitudes of Mars [ http://en.wikipedia.org/wiki/Mars ]. If confirmed, such water springs might make more of Mars hospitable to life [ http://mars.jpl.nasa.gov/science/life/ ] and human visitation [ http://www.nasa.gov/mission_pages/exploration/main/index.html ] than previously believed. |
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Mars Express Seen by Mars Gl
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| title |
Mars Express Seen by Mars Global Surveyor, This picture shows the Mars Express orbiter as a white, wavy, slanted streak centered against a vast, deep black background. The lines of the spacecraft make it appear somewhat like a jagged, three-inch worm in space. |
| Description |
This picture of the European Space Agency's Mars Express spacecraft by the Mars Orbiter Camera on NASA's Mars Global Surveyor is from the first successful imaging of any spacecraft orbiting Mars by another spacecraft orbiting Mars. The picture is a composite of two views of Mars Express that Mars Orbiter Camera acquired on April 20, 2005, from distances of about 250 and 370 kilometers (155 and 229 miles). Owing to the large distance between Mars Global Surveyor and Mars Express when the two views could be acquired and to a substantial cross-track component of apparent motion for which no correction could be made, Mars Express appears in the image as a narrow blur rather than as a well-defined spacecraft. It appears in the image to be about 1.5 meters in the small dimension and 15 meters in the long dimension, which is consistent with the viewing distance, pixel scale, and encounter geometry. The components of Mars Express when viewed from the same angle as this image can be seen in an artist's rendition http://photojournal.jpl.nasa.gov/figures/PIA07944_fig1.jpg and an annotated rendition http://photojournal.jpl.nasa.gov/figures/PIA07944_fig2.jpg of the spacecraft. Mars Express was launched on June 3, 2003, and reached Mars on Dec. 25, 2003. Mars Global Surveyor left Earth on Nov. 7, 1996, and arrived in Mars orbit on Sept. 12, 1997. JPL, a division of the California Institute of Technology, Pasadena, manages Mars Global Surveyor for NASA's Science Mission Directorate, Washingon, D.C. Credit: NASA/JPL/MSSS |
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Spirit Rover on 'Husband Hil
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| title |
Spirit Rover on 'Husband Hill' |
| Description |
Two Earth years ago, NASA's Mars Exploration Rover Spirit touched down in Gusev Crater. The rover marked its first Mars-year (687 Earth days) anniversary in November 2005. Shortly before Spirit's Martian anniversary, the Mars Orbiter Camera on NASA's Mars Global Surveyor acquired an image covering approximately 3 kilometers by 3 kilometers (1.9 miles by 1.9 miles) centered on the rover's location at that time in the "Columbia Hills.""Husband Hill," the tallest in the range, is just below the center of the image. The image has a resolution of about 50 centimeters (1.6 feet) per pixel. North is up, illumination is from the left. The location is near 14.8 degrees south latitude, 184.6 degrees west longitude. The image was acquired on Nov. 2, 2005. A white box indicates the location of an excerpted portion on which the location of Spirit on that date is marked. Dr. Timothy J. Parker of the Mars Exploration Rover team at the NASA's Jet Propulsion Laboratory, Pasadena, Calif., confirmed the location of the rover in the image. The region toward the bottom of the image shows the area where the rover is currently headed. The large dark patch and other similar dark patches are accumulations of windblown sand and granules. Credit: NASA/JPL-Caltech/MSSS |
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Scarp at Head of Chasma Bore
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| title |
Scarp at Head of Chasma Boreale |
| Description |
This view shows sharp detail of a scarp at the head of Chasma Boreale, a large trough cut by erosion into the martian north polar cap and the layered material beneath the ice cap. The picture is a mosaic of two images acquired in January 2005 by the Mars Orbiter Camera on NASA's Mars Global Surveyor, using a resolution-enhancing technique called "compensated pitch and roll targeted observation." The camera team considers this the best pair of images yet acquired using that technique. During each northern summer on Mars, there occurs a narrow window in time of two to three months when conditions are ideal to image the north polar cap at high resolution. Throughout this period, the atmosphere is generally clear over the cap, and the seasonal carbon-dioxide frost from the previous winter and spring has sublimed away, permitting a good view of the surface geology. The two images in this mosaic were acquired during this brief period during the most recent northern summer. Within a few weeks of when these images were acquired, dust storm activity picked up in the north polar region, making the atmosphere too dusty to obtain any more detailed views until late 2006. Chasma Boreale is cut into the layered material that lies beneath the water ice of the north polar cap. For decades, these layered materials were assumed to consist of a mixture of ice and dust. Mars Orbiter Camera images obtained in 1999 and 2001 began to show that some of the layers are a source for windblown sand. The science objective for the two images shown in this mosaic was to look for boulders in the debris shed from the steep slopes cut into the north polar layers by Chasma Boreale. Finding boulders would imply that the layers that are the most resistant to erosion in the polar region are as competent as solid rock, perhaps giving a new insight into the nature of the polar layered materials. The pictured site is near 84.8 degrees north latitude, 356.4 degrees west longitude. Examination of the high-resolution mosaic shows that there are indeed some large boulders that have eroded out of the layered materials and rolled down the slopes. It is possible, therefore, that the north polar layers are not simply a mixture of ice, dust, and sand. Some layers may actually be rock, cemented by minerals rather than by ice. Alternatively, if the materials are cemented by ice, then a future high-resolution view might show that the boulders have become smaller over time. In addition to the observation of boulders eroding out of the polar layered materials, the mosaic also helps confirm that dark sand is eroding out of the polar layered materials, and that there are three different groups of layers under the polar ice. The upper unit is light-toned, finely layered, and more resistant to erosion (more competent, less easily destroyed by erosion) than the middle unit, which is rich in dark sand but also has several shelf-forming layers in it. Finally, below the dark, sandy layer is a third unit, that is light-toned and has a different appearance relative to the other two units. Some of its layers have surfaces that have been broken by shallow fractures into polygonal and linear forms, also implying that they are hard, resistant rock. The level of detail seen in the mosaic was made possible by the development of a resolution-enhancing technique for using the Mars Orbiter Camera. During 2003 and 2004, the Mars Orbiter Camera operations team at Malin Space Science Systems, San Diego, Calif., worked closely with the Mars Global Surveyor operations teams at the Jet Propulsion Laboratory, Pasadena, Calif., and Lockheed Martin Space Systems, Denver, Colo., to develop a new technique in which the spacecraft does a maneuver that permits the camera to acquire images at a higher spatial resolution than normal. Usually, Mars Orbiter Camera images have a resolution of about 1.5 meters (5 feet) per pixel, and the camera can be commanded to acquire lower resolution data when desired. To obtain a higher resolution, the whole spacecraft must be pitched at such a rate that the camera over-samples its view of the martian surface in the down-track direction. Called compensated pitch and roll targeted observation, or cPROTO, this technique allows Mars Orbiter Camera to obtain images that have a resolution of about 50 centimeters (20 inches) per pixel in the down-track direction, and 150 centimeters (5 feet) per pixel in the cross-track dimension. The Mars Orbiter Camera was built and is operated by Malin Space Science Systems, San Diego, Calif. Mars Global Surveyor left Earth on Nov. 7, 1996, and began orbiting Mars on Sept. 12, 1997. JPL, a division of the California Institute of Technology, Pasadena, manages Mars Global Surveyor for NASA's Science Mission Directorate, Washington Credit: NASA/JPL/MSSS |
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Spirit's Neighborhood in 'Co
…
| title |
Spirit's Neighborhood in 'Columbia Hills,' in Stereo |
| Description |
Two Earth years ago, NASA's Mars Exploration Rover Spirit touched down in Gusev Crater. The rover marked its first Mars-year (687 Earth days) anniversary in November 2005. On Nov. 2, 2005, shortly before Spirit's Martian anniversary, the Mars Orbiter Camera on NASA's Mars Global Surveyor acquired an image covering approximately 3 kilometers by 3 kilometers (1.9 miles by 1.9 miles) centered on the rover's location in the "Columbia Hills." The tinted portion of this image gives a stereo, three-dimensional view when observed through 3-D glasses with a red left eye and blue right eye. The tallest peak is "Husband Hill," which was climbed by Spirit during much of 2005. The region south (toward the bottom) of these images shows the area where the rover is currently headed. The large dark patch and other similar dark patches in these images are accumulations of windblown sand and granules. North is up, illumination is from the left. The location is near 14.8 degrees south latitude, 184.6 degrees west longitude. Credit: NASA/JPL-Caltech/MSSS |
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Spirit on "Husband Hill," wi
…
| title |
Spirit on "Husband Hill," with 2004 Comparison |
| Description |
Two Earth years ago, NASA's Mars Exploration Rover Spirit touched down in Gusev Crater. The rover marked its first Mars-year (687 Earth days) anniversary in November 2005. On Nov. 2, 2005, shortly before Spirit's Martian anniversary, the Mars Orbiter Camera on NASA's Mars Global Surveyor acquired an image centered on the rover's location in the "Columbia Hills." The location of Spirit on that date is circled on the image on the right. On the left, for comparison, is an image from Jan. 10, 2004, when few dreamed that the Spirit would ever reach the hills from its landing site about three kilometers (two miles) away. The newer image has a resolution of about 50 centimeters (1.6 feet) per pixel. North is up, illumination is from the left. The location is near 14.8 degrees south latitude, 184.6 degrees west longitude. Dr. Timothy J. Parker of the Mars Exploration Rover team at NASA's Jet Propulsion Laboratory, Pasadena, Calif., confirmed the location of the rover in the 2005 image. The scale bar is 50 meters (164 feet). Credit: NASA/JPL-Caltech/MSSS |
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New Gullies on Martian Sand
…
| title |
New Gullies on Martian Sand Dune |
| Description |
One of the many mysteries associated with martian geology is the origin of gullies found at latitudes poleward of 30 degrees latitude. Most of these gullies are found within craters or other depressions, and appear to be related to the bedrock. Several hypotheses have been proposed for their origin, including groundwater seepage and melting at the base of a dust-mantled snow pack. Some middle-latitude gullies are found on sand dunes. These gullies appear to be different from those found on the slopes of craters, but generally have been interpreted to form by similar processes. In the present martian environment, it is difficult to introduce water to the surface. The temperature and atmospheric pressure may permit water to exist, but the rate of heating of the ground and atmosphere, and the amount of energy available to warm the ground or melt snow, are not conducive to such processes. An alternative process of gully formation on these sand dunes involves frozen carbon dioxide trapped in the winter by windblown sand, then subliming rapidly enough for the escaping carbon-dioxide gas to make the sand flow as a gully-cutting fluid. As part of extended-mission science investigation using the Mars Orbiter Camera on NASA's Mars Global Surveyor spacecraft, the camera team is re-imaging many locations where previous observations revealed gullies. The intent is to see if gully-forming processes are operating on Mars at the present time. The team has found one location where a new gully formed on a dune in an unnamed crater in the Hellespontus region of Mars, west of the Hellas Basin. This pair of narrow-angle images from the Mars Orbiter Camera shows the dune as it appeared on July 17, 2002, (left) and as it appeared on April 27, 2005, (right). The nearly three Earth years of intervening time amount to about 1.4 Mars years. During this period, a couple of gullies formed on the dune slip face. It is critical to recognize that the 2002 image was obtained at a time of year when the incident sunlight was coming in from a lower angle, relative to the horizon, than in the 2005 image. If the gullies had been present in 2002, their appearance would be sharper and more pronounced than they are in the 2005 image. The gullies simply did not exist on July 17, 2002. The steep walls of the gully alcove and channels suggests that the sand in this dune is somewhat cohesive, an observation common among martian sand dunes seen by the Mars Orbiter Camera over the past eight years. Wider context for the dune is shown in a mosaic of two images from the Thermal Emission Imaging System on NASA's Mars Odyssey orbiter (insert MOC2-1212a), encompassing the dark-toned sand dune field on the floor of a crater located near 49.8 degrees south latitude, 325.4 degrees west longitude. In this image, north is approximately up and sunlight illuminates the scene from the upper left. Based on earlier observations of other dune fields with gullies, camera-team scientists suspect that, these gullies form by a process other than water fluidization. An image of a dune in Russell Crater, taken by the Mars Orbiter Camera in March 2001, (insert MOC2-1212c) shows how the morphology of the dune's slip face changes with direction: Gullies form on pole-facing slopes (southwest in this case), while normal slip-face avalanche features ("avalanches" in the figure) are seen on the equator-facing slopes (northwest in this case). Most of the dunes that have gullies on them are located in the Hellespontus and Noachis regions, and are frost-covered during the winter. Based on experience in Antarctica and other cold regions on Earth, it is known that snow and ice can be incorporated into dunes during winter. An example is the layering of snow buried in a sand dune in Victoria Valley, Antarctica, seen in a photograph taken by Michael Malin during the austral summer of 1982-1983 (insert MOC2-1212d). Active sand dunes in cold regions such as Antarctica and northern Canada commonly incorporate wintertime snow as new sand avalanches down a slip face and covers the frozen material. A similar process might occur for middle and high latitude dunes on Mars, although in many cases the "snow" would consist mostly of carbon-dioxide frost, with minimal water ice. What would happen to carbon-dioxide frost incorporated into a martian sand dune? On surfaces that receive early and direct sunlight, the sand would heat and the carbon-dioxide frost would sublime over a period of time, undermining the slope and promoting normal sand sliding. On slopes that were initially shaded and later exposed to direct sunlight, heating would be delayed and the carbon dioxide frost would sublime rapidly. This rapid formation of carbon-dioxide gas may act to fluidize overlying sand, causing it to flow rather than avalanche, and thus create a gully. The Mars Orbiter Camera was built and is operated by Malin Space Science Systems, San Diego, Calif. Mars Global Surveyor left Earth on Nov. 7, 1996, and began orbiting Mars on Sept. 12, 1997. JPL, a division of the California Institute of Technology, Pasadena, manages Mars Global Surveyor for NASA's Science Mission Directorate, Washington. Credit: NASA/JPL/MSSS/ASU |
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Mars Reconnaissance Orbiter
| title |
Mars Reconnaissance Orbiter |
| Description |
In 2005, NASA plans to launch a powerful scientific orbiter, the Mars Reconnaissance Orbiter. This mission will focus on analyzing the surface at new scales in an effort to follow tantalizing hints of water detected in images from the Mars Global Surveyor spacecraft, and to bridge the gap between surface observations and measurements from orbit. For example, the Reconnaissance Orbiter will measure thousands of Martian landscapes at 20- to 30-centimeter (8- to 12-inch) resolution, good enough to observe rocks the size of beach balls. |
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Olivine-Rich Bedrock Around
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| title |
Olivine-Rich Bedrock Around Nili Fossae |
| Description |
Colors indicate infrared emission signatures in this mosaic of images from NASA's Mars Odyssey orbiter of a region of martian troughs named Nili Fossae. Analysis of this information from Odyssey's Thermal Emission Imaging System suggests that a deposit rich in the mineral olivine is about four times larger than indicated in earlier data from a lower-resolution infrared instrument on NASA's Mars Global Surveyor. The olivine-rich exposures appear magenta to purple-blue in this color-coding. Olivine can turn into other minerals rapidly in the presence of water. This deposit, in a relatively old region of Mars' surface adjacent to one of the planet's largest volcanoes, Syrtis Major, suggests the region may never have seen much water. The mosaic covers most of an area about 380 kilometers (about 240 miles) wide, from 75 degrees to 81 degrees in east longitude and from 18 degrees to 25 degrees in north latitude. North is up. Emission intensities at infrared wavelengths of 12.57 nanometers, 11.04 nanometers and 9.35 nanometers are displayed in red, green and blue, respectively. This mosaic was presented in a report in the June 2005 issue of the journal Geology. For additional information about that report, see a University of Hawaii press release [ http://www.soest.hawaii.edu/SOEST_News/News/PressReleases/Hamilton/ ]. Credit: NASA/JPL/ASU |
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| Description |
Browse Image | Medium Image (129 kB) | Large (20.4 MB) Hi-Res (NASA's Planetary Photojournal) [ http://photojournal.jpl.nasa.gov/catalog/PIA08813 ] |
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Mars Odyssey Seen by Mars Gl
…
| title |
Mars Odyssey Seen by Mars Global Surveyor (3-D) |
| Description |
This stereoscopic picture of NASA's Mars Odyssey spacecraft was created from two views of that spacecraft taken by the Mars Orbiter Camera on NASA's Mars Global Surveyor. The camera's successful imaging of Odyssey and of the European Space Agency's Mars Express in April 2005 produced the first pictures of any spacecraft orbiting Mars ever taken by another spacecraft orbiting Mars. Mars Global Surveyor acquired this image of Mars Odyssey on April 21, 2005. The stereoscopic picture combines one view captured while the two orbiters were 90 kilometers (56 miles) apart with a second view captured from a slightly different angle when the two orbiters were 135 kilometers (84 miles) apart. For proper viewing, the user needs "3-D" glasses with red over the left eye and blue over the right eye. The Mars Orbiter Camera can resolve features on the surface of Mars as small as a few meters or yards across from Mars Global Surveyor's orbital altitude of 350 to 405 kilometers (217 to 252 miles). From a distance of 100 kilometers (62 miles), the camera would be able to resolve features substantially smaller than 1 meter or yard across. Mars Odyssey was launched on April 7, 2001, and reached Mars on Oct. 24, 2001. Mars Global Surveyor left Earth on Nov. 7, 1996, and arrived in Mars orbit on Sept. 12, 1997. Both orbiters are in an extended mission phase, both have relayed data from the Mars Exploration Rovers, and both are continuing to return exciting new results from Mars. JPL, a division of the California Institute of Technology, Pasadena, manages both missions for NASA's Science Mission Directorate, Washington, D.C. Credit: NASA/JPL/MSSS |
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Wind Erosion in Tithonium
PIA07890
Sol (our sun)
Mars Orbiter Camera
| Title |
Wind Erosion in Tithonium |
| Original Caption Released with Image |
30 April 2005 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows wind-eroded sedimentary rocks in Tithonium Chasma, one of the troughs of the Valles Marineris system. The winds responsible for the majority of the erosion blew from the northeast (upper right), creating yardangs (wind erosion ridges) with their tapered ends pointing downwind. "Location near": 4.6°S, 88.3°W "Image width": ~3 km (~1.9 mi) "Illumination from": upper left "Season": Southern Winter |
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Martian Gullies
PIA04146
Sol (our sun)
Mars Orbiter Camera
| Title |
Martian Gullies |
| Original Caption Released with Image |
13 August 2005 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows gullies cut into layered rock and debris on the wall of a south middle-latitude crater. Gullies such as these are common at middle latitudes and may have required water to form. "Location near": 41.1°S, 204.8°W "Image width": width: ~3 km (~1.9 mi) "Illumination from": upper left "Season": Southern Spring |
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East Candor Outcrops
PIA03922
Sol (our sun)
Mars Orbiter Camera
| Title |
East Candor Outcrops |
| Original Caption Released with Image |
30 May 2005 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows light-toned, wind-eroded, sedimentary rock outcrops in eastern Candor Chasma, part of the Valles Marineris trough system. "Location near": 7.7°S, 65.3°W "Image width": ~3 km (~1.9 mi "Illumination from": lower left "Season": Southern Spring |
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Seasonal Trend in Water Vapo
…
PIA07102
Sol (our sun)
Thermal Emission Spectromete
…
| Title |
Seasonal Trend in Water Vapor Seen from Orbit |
| Original Caption Released with Image |
The seasonal trend in the amount of water vapor in Mars' atmosphere, as observed by thermal emission spectrometer on NASA's Mars Global Surveyor orbiter, varies by latitude. This plot starts near the beginning of fall in the southern hemisphere for the year before the Mars Exploration Rover mission began and ends on August 30, 2004, slightly more than one martian year later. Purple represents no water while red represents about 50 precipitable micrometers, which is about 10,000 times less than on Earth. The units of time along the horizontal axis are given in longitude of the Sun (Ls) as measured in a Mars-centered coordinate system, a way to reflect the elliptical nature of Mars' orbit. On this scale, Mars is farthest from the Sun at about 74, which also corresponds to late fall in the southern hemisphere. During the period when Mars is farthest from the Sun, the migration of water vapor from the northern polar region combines with lowered atmospheric temperatures to produce conditions that allow formation of clouds such as seen in the image at PIA07105 [ http://photojournal.jpl.nasa.gov/catalog/PIA07105 ]. Opportunity is further north than Spirit is, so there is a distinct difference in the amount of water vapor available to form water-ice clouds over the two sites. To date, Spirit has not seen any discrete, cirrus-like clouds such as Opportunity has photographed. Although water vapor is expected to reach a maximum abundance for the Opportunity and Spirit sites near spring equinox (Ls 180 or about March 2005), the atmospheric temperatures will very likely have warmed sufficiently to prevent formation of the type of clouds that Opportunity has observed recently. |
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East Tharsis Pit Chain
PIA03987
Sol (our sun)
Mars Orbiter Camera
| Title |
East Tharsis Pit Chain |
| Original Caption Released with Image |
7 July 2005 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows dark, windblown sand dunes in the caldera of Nili Patera, a volcanic crater in Syrtis Major. The dunes were formed by winds blowing from the northeast (upper right). "Location near": 16.0°N, 93.1°W"Image width": ~3 km (~1.9 mi) "Illumination from": lower left "Season" Northern Autumn |
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Frozen Frozen CO2
PIA03008
Sol (our sun)
Mars Orbiter Camera
| Title |
Frozen Frozen CO2 |
| Original Caption Released with Image |
2 October 2005 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a view of frozen carbon dioxide in the south polar residual cap of Mars. Much of the south polar residual cap exhibits terrain that resembles stacks of sliced Swiss cheese, but this portion of the cap lacks the typical, circular depressions that characterize much of the region. Carbon dioxide on Mars freezes at a temperature of around 148 Kelvins, which is -125°C or about -193°F. "Location near": 87.2°S, 28.4°W "Image width": width: ~3 km (~1.9 mi) "Illumination from": upper left "Season": Southern Spring |
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West Tithonium Scene
PIA03968
Sol (our sun)
Mars Orbiter Camera
| Title |
West Tithonium Scene |
| Original Caption Released with Image |
26 June 2005 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows dark rippled surfaces and a patch of light-toned, perhaps sedimentary rock exposed on the floor of western Tithonium Chasma, part of the vast Valles Marineris trough system. "Location near": 5.0°S, 90.3°W "Image width": ~3 km (~1.9 mi) "Illumination from": lower left "Season" Southern Spring |
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West Arabia Barchans
PIA04101
Sol (our sun)
Mars Orbiter Camera
| Title |
West Arabia Barchans |
| Original Caption Released with Image |
16 July 2005 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows small barchan dunes on the floor of a crater in western Arabia Terra. Similar dunes are found in most of the larger craters of the region. The steepest slopes on these dunes, their slipfaces, point toward the west-southwest, indicating that dominant winds blow from the east-northeast (upper right). "Location near": 10.9°N, 2.8°W "Image width": width: ~3 km (~1.9 mi) "Illumination from": lower left "Season": Northern Autumn |
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Enhanced by Frost
PIA03006
Sol (our sun)
Mars Orbiter Camera
| Title |
Enhanced by Frost |
| Original Caption Released with Image |
30 September 2005 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows outcrops of south polar layered terrain. Their appearance in this July 2005 springtime image is enhanced by bright patches of carbon dioxide frost. The frost is left over from the previous southern winter season, by summer, the frost would be gone. "Location near": 84.6°S, 203.5°W "Image width": width: ~3 km (~1.9 mi) "Illumination from": upper left "Season": Southern Spring |
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Mars at Ls 306°: Tharsis
PIA03016
Sol (our sun)
Mars Orbiter Camera
| Title |
Mars at Ls 306°: Tharsis |
| Original Caption Released with Image |
4 October 2005 This picture is a composite of Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) daily global images acquired at Ls 306° during a previous Mars year. This month, Mars looks similar, as Ls 306° occurs in mid-October 2005. The picture shows the Tharsis face of Mars. Over the course of the month, additional faces of Mars as it appears at this time of year are being posted for MOC Picture of the Day. Ls, solar longitude, is a measure of the time of year on Mars. Mars travels 360° around the Sun in 1 Mars year. The year begins at Ls 0°, the start of northern spring and southern autumn. "Season": Northern Winter/Southern Summer |
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Inverted Channels
PIA03004
Sol (our sun)
Mars Orbiter Camera
| Title |
Inverted Channels |
| Original Caption Released with Image |
18 September 2005 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows the inverted remains of several channels in a fan-like complex in the Aeolis region of Mars. The inverted channels are the flat-topped ridges that trend from lower right toward upper left (southeast to northwest). Other ridges, trending from lower left toward upper right (southwest to northeast) are yardangs, the products of wind erosion. The channels were inverted by erosion, as well -- the tops of these ridges were once the floor of the channels (or the tops of materials that filled the channels). "Location near": 5.1°S, 205.0°W "Image width": width: ~3 km (~1.9 mi) "Illumination from": lower left "Season": Southern Spring |
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Dike near Auqakuh
PIA03037
Sol (our sun)
Mars Orbiter Camera
| Title |
Dike near Auqakuh |
| Original Caption Released with Image |
13 October 2005 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a dike exhumed by erosion from beneath the cratered terrain near Auqakuh Vallis in northeastern Arabia Terra. The dike is the narrow, discontinuous ridge that cuts diagonally from the northwest (upper left) toward the southeast (lower right) across the scene. Typically, a dike is formed underground when molten rock -- "magma" -- is injected through a crack or fault. The magma eventually cools and hardens. A dike can also sometimes form in a non-volcanic setting by injection of wet sediment (which later hardens to rock) into an overlying sedimentary layer. The ridge is formed later, when surrounding rocks are eroded away, leaving the more erosion-resistant rock behind as a ridge. For an example on Earth, the famous Shiprock in northwestern New Mexico, U.S.A., has several dikes associated with it. "Location near": 31.4°N, 299.0°W "Image width": width: ~3 km (~1.9 mi) "Illumination from": lower left "Season": Northern Winter |
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South Polar Scene
PIA03020
Sol (our sun)
Mars Orbiter Camera
| Title |
South Polar Scene |
| Original Caption Released with Image |
8 October 2005 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows two circular features in the south polar region of Mars. The circular features are degraded impact craters. The dark, irregular features in each crater are the remnants of a layer of material that probably once covered the entire scene, before being eroded away. All of the terrain in this image is covered by defrosting, seasonal carbon dioxide frost. "Location near": 79.5°S, 295.0°W "Image width": width: ~3 km (~1.9 mi) "Illumination from": upper left "Season": Southern Spring |
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Martian Flows
PIA03021
Sol (our sun)
Mars Orbiter Camera
| Title |
Martian Flows |
| Original Caption Released with Image |
9 October 2005 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows several overlapping lava flows located on the vast plains east of the volcano, Ascraeus Mons. Hundreds of lava flows cover the plains from Ascraeus Mons eastward to Kasei Valles. These flows have largely been mantled by fine dust, a few areas in the image exhibit dark streaks, where wind gusts have stripped away some of this thin dust mantle. "Location near": 5.2°N, 86.7°W "Image width": width: ~3 km (~1.9 mi) "Illumination from": lower left "Season": Northern Autumn |
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Crater in Sabaeus
PIA03036
Sol (our sun)
Mars Orbiter Camera
| Title |
Crater in Sabaeus |
| Original Caption Released with Image |
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": 6.3°S, 341.7°W "Image width": width: ~3 km (~1.9 mi) "Illumination from": lower left "Season": Southern Spring |
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Wind-Eroded Terrain
PIA03003
Sol (our sun)
Mars Orbiter Camera
| Title |
Wind-Eroded Terrain |
| Original Caption Released with Image |
17 September 2005 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a wind-eroded terrain. The ridges that cut across the scene from the lower right toward upper left (southeast to northwest) are classic yardangs, a landform created by wind erosion. These are located in the Eumenides Dorsum region of Mars. "Location near": 5.5°N, 159.0°W "Image width": width: ~3 km (~1.9 mi) "Illumination from": lower left "Season": Northern Autumn |
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Arabian Crater
PIA03018
Sol (our sun)
Mars Orbiter Camera
| Title |
Arabian Crater |
| Original Caption Released with Image |
6 October 2005 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows an old impact crater in southeastern Arabia Terra. The crater ejecta blanket is no longer visible and all of the terrain has been covered by a mantle of dust. The dark streaks on the crater wall are the result of dry avalanches of dust, the darker streaks formed more recently than the lighter-toned streaks. Indeed, the darkest streak is likely to be less than a few years old. "Location near": 3.0°N, 315.6°W "Image width": width: ~3 km (~1.9 mi) "Illumination from": lower left "Season": Northern Autumn |
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Defrosting South #2
PIA03007
Sol (our sun)
Mars Orbiter Camera
| Title |
Defrosting South #2 |
| Original Caption Released with Image |
1 October 2005 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a second view of varied springtime defrosting patterns formed in a dune field and surrounding polygon-patterned ground in the south polar region of Mars. The previous view was featured as a MOC Picture of the Day on 20 August 2005 (PIA04162 [ http://photojournal.jpl.nasa.gov/catalog/PIA04162 ]). Both images show portions of the same terrain and occur within a few hundred meters of each other. The previous release explained that the feature sporting an outline of dark spots and an interior of smaller, closely-spaced dark spots and dark-outlined polygons is a patch of windblown or wind-eroded sand that was covered by carbon dioxide frost during the previous autumn and winter. The fainter, larger polygon pattern on either side of the patch of defrosting sand is formed in the substrate upon which the sand patch is sitting. Polygonal forms such as these might indicate the presence of ice below the surface. "Location near": 79.9°S, 125.9°W "Image width": width: ~3 km (~1.9 mi) "Illumination from": upper left "Season": Southern Spring |
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Huygens Wind Streak
PIA03005
Sol (our sun)
Mars Orbiter Camera
| Title |
Huygens Wind Streak |
| Original Caption Released with Image |
19 September 2005 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows the results of wind action on the floor of the giant martian impact basin, Huygens. The large crater in this image has a wind streak on its lee side, pointing toward the lower right (southeast). Usually, a light-toned wind streak behind a crater on Mars will be composed of a thin veneer of dust that the wind was not able to erode because it was protected by the presence of the crater's raised rims. In this case, the streak is caused by something different -- by the fact that dark, windblown sand has not been able to accumulate behind the crater. "Location near": 13.0°S, 303.7°W "Image width": width: ~3 km (~1.9 mi) "Illumination from": lower left "Season": Southern Spring |
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Mars at Ls 306°: Acidalia/Ma
…
PIA03027
Sol (our sun)
Mars Orbiter Camera
| Title |
Mars at Ls 306°: Acidalia/Mare Erythraeum |
| Original Caption Released with Image |
11 October 2005 This picture is a composite of Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) daily global images acquired at Ls 306° during a previous Mars year. This month, Mars looks similar, as Ls 306° occurs in mid-October 2005. The picture shows the Acidalia/Mare Erythraeum face of Mars. Over the course of the month, additional faces of Mars as it appears at this time of year are being posted for MOC Picture of the Day. Ls, solar longitude, is a measure of the time of year on Mars. Mars travels 360° around the Sun in 1 Mars year. The year begins at Ls 0°, the start of northern spring and southern autumn. "Season": Northern Winter/Southern Summer |
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Volcanic Pit Chain
PIA03017
Sol (our sun)
Mars Orbiter Camera
| Title |
Volcanic Pit Chain |
| Original Caption Released with Image |
5 October 2005 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a chain of collapse pits on the lower south flank of Ascraeus Mons. Pit chains such as this are the result of collapse along fault lines. In this case, before the collapses occurred, the fault was a conduit for molten rock -- magma -- which erupted to form a suite of lava flows (now covered by mantles of dust) that can be seen radiating away from the pit at the center of the image. "Location near": 7.2°N, 104.3°W "Image width": width: ~3 km (~1.9 mi) "Illumination from": lower left "Season": Northern Autumn |
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Wind Streak in Daedalia
PIA03050
Sol (our sun)
Mars Orbiter Camera
| Title |
Wind Streak in Daedalia |
| Original Caption Released with Image |
20 October 2005 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a wind streak formed in the lee of an impact crater in western Daedalia Planum. "Location near": 12.7°S, 136.6°W "Image width": width: ~3 km (~1.9 mi) "Illumination from": lower left "Season": Southern Spring |
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Exhuming Landforms
PIA03071
Sol (our sun)
Mars Orbiter Camera
| Title |
Exhuming Landforms |
| Original Caption Released with Image |
26 October 2005 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a crater and adjacent terrain that have been exhumed from beneath a wind-eroded material. The sharp, pointy ridges inside and immediately adjacent to the crater are the remains of a material that once covered the entire scene. Wind has stripped these materials away, forming yardangs. Inside the crater, the erosion has revealed an older, eroded layered material. This smooth-surfaced layered feature inside the crater was already eroded to nearly its present shape before the yardang-forming material was deposited (and then eroded away). "Location near": 7.2°N, 156.4°W "Image width": width: ~3 km (~1.9 mi) "Illumination from": lower left "Season": Northern Winter |
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Sirenum Fossae Troughs
PIA03051
Sol (our sun)
Mars Orbiter Camera
| Title |
Sirenum Fossae Troughs |
| Original Caption Released with Image |
21 October 2005 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows two troughs/depressions formed along the trend of the Sirenum Fossae, a suite of very extensive troughs formed by faults that are radial to the giant Tharsis Bulge. As the Tharsis region bulged outward, adjacent terrain expanded and formed a series of long, extensional fault systems. "Location near": 26.4°S, 142.4°W "Image width": width: ~3 km (~1.9 mi) "Illumination from": lower left "Season": Southern Spring |
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Cerberus Flood Features
PIA03043
Sol (our sun)
Mars Orbiter Camera
| Title |
Cerberus Flood Features |
| Original Caption Released with Image |
16 October 2005 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows streamlined landforms carved by catastrophic floods that occurred in the eastern Cerberus region, some time in the distant martian past. "Location near": 15.1°N, 193.5°W "Image width": width: ~3 km (~1.9 mi) "Illumination from": lower left "Season": Northern Autumn |
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Mars at Ls 306°: Elysium/Mar
…
PIA03069
Sol (our sun)
Mars Orbiter Camera
| Title |
Mars at Ls 306°: Elysium/Mare Cimmerium |
| Original Caption Released with Image |
25 October 2005 This picture is a composite of Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) daily global images acquired at Ls 306° during a previous Mars year. This month, Mars looks similar, as Ls 306° occurred in mid-October 2005. The picture shows the Elysium/Mare Cimmerium face of Mars. Over the course of the month, additional faces of Mars as it appears at this time of year are being posted for MOC Picture of the Day. Ls, solar longitude, is a measure of the time of year on Mars. Mars travels 360° around the Sun in 1 Mars year. The year begins at Ls 0°, the start of northern spring and southern autumn. "Season": Northern Winter/Southern Summer |
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Mars at Ls 306°: Syrtis Majo
…
PIA03045
Sol (our sun)
Mars Orbiter Camera
| Title |
Mars at Ls 306°: Syrtis Major |
| Original Caption Released with Image |
18 October 2005 This picture is a composite of Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) daily global images acquired at Ls 306° during a previous Mars year. This month, Mars looks similar, as Ls 306° occurs in mid-October 2005. The picture shows the Syrtis Major face of Mars. Over the course of the month, additional faces of Mars as it appears at this time of year are being posted for MOC Picture of the Day. Ls, solar longitude, is a measure of the time of year on Mars. Mars travels 360° around the Sun in 1 Mars year. The year begins at Ls 0°, the start of northern spring and southern autumn. "Season": Northern Winter/Southern Summer |
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Martian Lava Flows
PIA03049
Sol (our sun)
Mars Orbiter Camera
| Title |
Martian Lava Flows |
| Original Caption Released with Image |
19 October 2005 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows lava flows at the southeast base of the giant volcano, Olympus Mons. The flat plain in the south-southeast (bottom/lower right) portion of the image is younger than and cuts off the ends of many of the lava flows that came from the northwest (upper left). Many of the lava flows in this image exhibit channels with levees bounding their margins. As each lava flow was advancing, its outer margins cooled and hardened, forming a channel or tube through which the molten rock continued to advance. "Location near": 17.2°N, 129.0°W "Image width": width: ~3 km (~1.9 mi) "Illumination from": lower left "Season": Northern Winter |
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Zephyria Platy Flows
PIA03066
Sol (our sun)
Mars Orbiter Camera
| Title |
Zephyria Platy Flows |
| Original Caption Released with Image |
22 October 2005 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows the broken, platy texture of flow surfaces in the Zephyria region of Mars. Some investigators have suggested that these materials represent the remains of an ice-covered lake, others suggest that these are the surfaces of hardened lava that -- when it was erupting -- was very hot and fluid. Although not illustrated here, a key piece of evidence against the ice-covered lake hypothesis is that there are some small craters formed on these surfaces (one can be seen in the lower left/southwest corner), and some of them have boulders in their ejecta. The boulders indicate that the material is rock-solid. "Location near": 5.3°N, 208.6°W "Image width": width: ~3 km (~1.9 mi) "Illumination from": lower left "Season": Northern Autumn |
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Flows in Kasei
PIA03073
Sol (our sun)
Mars Orbiter Camera
| Title |
Flows in Kasei |
| Original Caption Released with Image |
28 October 2005 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows flow materials-on the east/right side of the image-that have come in among a suite of sharp ridges and grooves on the floor of the vast Kasei Valles system. The ridges and grooves are much older and are believed to be the result of a giant, catastrophic flood. The flows might have been mud or lava that ran part way down the ancient valley at a later date. "Location near": 16.7°N, 76.5°W "Image width": width: ~3 km (~1.9 mi) "Illumination from": lower left "Season": Northern Winter |
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Crater and Flows
PIA03074
Sol (our sun)
Mars Orbiter Camera
| Title |
Crater and Flows |
| Original Caption Released with Image |
29 October 2005 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a crater surrounded by thin flows in southeastern Kasei Valles. The flows might have been lava or mud. The picture was acquired in August 2005. "Location near": 14.2°N, 75.1°W "Image width": width: ~3 km (~1.9 mi) "Illumination from": left/lower left "Season": Northern Autumn |
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Filled/Eroded Craters
PIA03038
Sol (our sun)
Mars Orbiter Camera
| Title |
Filled/Eroded Craters |
| Original Caption Released with Image |
14 October 2005 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows rugged terrain in northern Arabia Terra. The circular features are the remains of old meteor impact craters -- either the eroded remnants of the interiors of craters, or the remains of craters that were filled by layered material. The martian bedrock has craters of all sizes and states of erosion interbedded with its layered materials. "Location near": 31.4°N, 299.0°W "Image width": width: ~3 km (~1.9 mi) "Illumination from": lower left "Season": Northern Winter |
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East Arabia Mesas
PIA03075
Sol (our sun)
Mars Orbiter Camera
| Title |
East Arabia Mesas |
| Original Caption Released with Image |
30 October 2005 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows mesas and other eroded landforms in eastern Arabia Terra, near Huo Hsing Vallis. Arabia Terra is generally a cratered terrain that has been severely eroded, although the causes of the erosion -- and where all the material went when it was removed -- are not known. "Location near": 27.3°N, 293.2°W "Image width": width: ~3 km (~1.9 mi) "Illumination from": lower left "Season": Northern Summer |
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East Arabia Scene
PIA03067
Sol (our sun)
Mars Orbiter Camera
| Title |
East Arabia Scene |
| Original Caption Released with Image |
23 October 2005 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows mesas in northeastern Arabia Terra. This heavily-cratered region of Mars has been severely eroded, although very little evidence regarding the erosive processes has been preserved. "Location near": 26.9°N, 293.5°W "Image width": width: ~3 km (~1.9 mi) "Illumination from": lower left "Season": Northern Autumn |
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Defrosting Terrain
PIA03098
Sol (our sun)
Mars Orbiter Camera
| Title |
Defrosting Terrain |
| Original Caption Released with Image |
9 November 2005 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a south polar scene, covered by bright, seasonal, carbon dioxide frost. The dark patches are areas where the frost has begun to sublime away. "Location near": 80.0°S, 334.0°W "Image width": width: ~3 km (~1.9 mi) "Illumination from": upper left "Season": Southern Spring |
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Isidis Planitia
PIA03087
Sol (our sun)
Mars Orbiter Camera
| Title |
Isidis Planitia |
| Original Caption Released with Image |
3 November 2005 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a cratered surface in Isidis Planitia, a martian lowland. Light-toned "squiggles" in this August 2005 image are large windblown ripples. "Location near": 10.6°N, 275.2°W "Image width": width: ~3 km (~1.9 mi) "Illumination from": lower left "Season": Northern Autumn |
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Russell Dune Gullies
PIA03089
Sol (our sun)
Mars Orbiter Camera
| Title |
Russell Dune Gullies |
| Original Caption Released with Image |
5 November 2005 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows gullies and dust devil streaks on the slopes of a large dune in Russell Crater. Gullies on martian dunes typically occur only in the Noachis Terra region, and almost exclusively form on southward-facing slopes. They might be the result of downslope movement of sand mixed with a fluid such as carbon dioxide gas or water that had been trapped as ice in the dune. "Location near": 54.6°S, 347.2°W "Image width": width: ~3 km (~1.9 mi) "Illumination from": upper left "Season": Southern Spring |
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