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Artist's concept of Mars Ody
…
| Title |
Artist's concept of Mars Odyssey |
| Description |
Artist's concept of 2001 Mars Odyssey spacecraft |
| Date |
12.21.2002 |
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Acheron Fossae in Visible Li
…
| title |
Acheron Fossae in Visible Light |
| Description |
This visible-light image, taken by the thermal emission imaging system's camera on NASA's 2001 Mars Odyssey spacecraft, shows the highly fractured, faulted and deformed Acheron Fossae region of Mars. The scarps visible in this image are approximately one kilometer (3,300 feet) high, based on topography derived from the laser altimeter instrument on Mars Global Surveyor. Dark streaks only 50 meters (164 feet) across can be seen on some of the cliff faces. These streaks may be formed when the pervasive dust mantle covering this region gives way on steep slopes to create dust avalanches. The image also shows impact craters as small as 500 meters (1,640 feet) in diameter, as well as smooth and textured plains. Acheron Fossae is located 1,050 kilometers (650 miles) north of the large shield volcano Olympus Mons. This image covers an area about 18 by 9 kilometers (11 by 6 miles) centered at 37 degrees north, 131 degrees west. North is to the top of this image, which was acquired on February 19, 2002, at about 3:15 p.m. local Martian 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 was provided by Arizona State University, Tempe. Lockheed Martin Astronautics, Denver, is the prime contractor for the 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. Photo Credit: NASA/Jet Propulsion Laboratory/Arizona State University |
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Western Arcadia Planitia
| title |
Western Arcadia Planitia |
| Description |
This is a Mars Odyssey visible color image of an unnamed crater in western Arcadia Planitia (near 39 degrees N, 179 degrees E). The crater shows a number of interesting internal and external features that suggest that it has undergone substantial modification since it formed. These features include concentric layers and radial streaks of brighter, redder materials inside the crater, and a heavily degraded rim and ejecta blanket. The patterns inside the crater suggest that material has flowed or slumped towards the center. Other craters with features like this have been seen at both northern and southern mid latitudes The distribution of these kinds of craters suggests the possible influence of surface or subsurface ice in the formation of these enigmatic features. The image was taken on September 29, 2002 during late northern spring. This is an approximate true color image, generated from a long strip of visible red (654 nm), green (540 nm), and blue (425 nm) filter images that were calibrated using a combination of pre-flight measurements and Hubble images of Mars. The colors appear perhaps a bit darker than one might expect, this is most likely because the images were acquired in late afternoon (roughly 4:40 p.m. local solar time) and the low Sun angle results in an overall darker surface. 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 was provided by Arizona State University, Tempe. Lockheed Martin Astronautics, Denver, Colo., is the prime contractor for the 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. Credit: NASA/JPL/Arizona State University/Cornell University |
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Mars Ice Age, Simulated
| title |
Mars Ice Age, Simulated |
| Description |
Infrared imaging from NASA's Mars Odyssey spacecraft shows signs of layering exposed at the surface in a region of Mars called Terra Meridiani. The brightness levels show daytime surface temperatures, which range from about minus 20 degrees to zero degrees Celsius (minus 4 degrees to 32 degrees Fahrenheit). Many of the temperature variations are due to slope effects, with sun-facing slopes warmer than shaded slopes. However, several rock layers can be seen to have distinctly different temperatures, indicating that physical properties vary from layer to layer. These differences suggest that the environment on this part of Mars varied through time as these layers were formed. The image is a mosaic combining four exposures taken by the thermal emission imaging system aboard Odyssey during the first two months of the Odyssey mapping mission, which began in February 2002. The area shown is about 120 kilometers (75 miles) across, at approximately 358 degrees east (2 degrees west) longitude and 3 degrees north latitude. 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 was provided by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. Lockheed Martin Astronautics, Denver, is the prime contractor for the project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and JPL. JPL is a division of the California Institute of Technology in Pasadena. Credit: NASA/JPL/Arizona State University |
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Mars Surface Layers in Infra
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| title |
Mars Surface Layers in Infrared |
| Description |
Infrared imaging from NASA's Mars Odyssey spacecraft shows signs of layering exposed at the surface in a region of Mars called Terra Meridiani. The brightness levels show daytime surface temperatures, which range from about minus 20 degrees to zero degrees Celsius (minus 4 degrees to 32 degrees Fahrenheit). Many of the temperature variations are due to slope effects, with sun-facing slopes warmer than shaded slopes. However, several rock layers can be seen to have distinctly different temperatures, indicating that physical properties vary from layer to layer. These differences suggest that the environment on this part of Mars varied through time as these layers were formed. The image is a mosaic combining four exposures taken by the thermal emission imaging system aboard Odyssey during the first two months of the Odyssey mapping mission, which began in February 2002. The area shown is about 120 kilometers (75 miles) across, at approximately 358 degrees east (2 degrees west) longitude and 3 degrees north latitude. 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 was provided by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. Lockheed Martin Astronautics, Denver, is the prime contractor for the project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and JPL. JPL is a division of the California Institute of Technology in Pasadena. Credit: NASA/JPL/Arizona State University |
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Odyssey/ Becquerel
| title |
Odyssey/ Becquerel |
| Description |
These images from Mars Odyssey look at the Becquerel crater in different lights -- visible, daytime infrared and nighttime infrared. The daytime images (left and center) were acquired on March 28, 2002 and the nighttime image (right) was acquired on March 2, 2002, by the thermal emission imaging system aboard Mars Odyssey. Thermal infrared is the wavelength range associated with heat. Looking at the Martian surface in the infrared wavelengths allows scientists to identify and distinguish bedrock from sand or dust covered areas. The Becquerel deposit is relatively bright in the visible wavelengths. Its surface has been scoured by windblown sand to produce the ridged topography seen in the visible image, which spans an 18-kilometer (11 mile)-wide portion of the deposit. Dark sand is seen in the lower right of the visible image. This same scene in the 32-kilometer (20 mile)-wide daytime infrared image looks remarkably similar to a photographic negative of the visible image due to the effects of solar heating. Darker tones represent cooler surfaces, brighter tones are warmer ones. During the day, visibly dark surfaces heat up much more efficiently than bright surfaces. The relatively bright sediments of the mound reflect more solar energy than the darker sand, allowing the mound to stay cooler than the sand. In the nighttime infrared image, the mound and the sand are warmer than their surroundings. The dark portions of the image represent cold surfaces that are covered in dust particles. Dust does not retain heat during the cold Martian night and quickly gives up any heat received during the day. Sand particles, because they are larger than dust particles, are able to retain heat better, producing the brighter swath around the mound. The infrared image has a resolution of 100 meters (328 feet) per pixel and is 32 kilometers (20 miles) wide. The visible image has a resolution of 18 meters per pixel and is approximately 18 kilometers (11 miles) wide. The images are centered at 21.4 degrees north latitude and 351.8 degrees east longitude. 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 was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. 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. Credit: NASA/JPL/Arizona State University |
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Odyssey/Ganges
| title |
Odyssey/Ganges |
| Description |
These Mars Odyssey images show layered deposits located on the floor of Ganges Chasma, part of the Valles Marineris canyon system, in both infrared (left) and visible (right) wavelengths. The images were acquired simultaneously by the thermal emission imaging system on March 17, 2002. The box shows where the visible image is located wthin the infrared image. The infrared image displays variations in surface temperature where bright tones indicate warmer surfaces and dark tones are cooler ones. Dramatic layering can be seen throughout the central deposit in both the infrared and visible images. Different styles of erosion are shown in these different layers, suggesting that Mars was subject to changing environments during its history. The infrared image has a resolution of 100 meters (328 feet) per pixel and is 32 kilometers (20 miles) wide. The visible image has a resolution of 18 meters per pixel and is approximately 18 kilometers (11 miles) wide. Pixel brightness in the infrared image is controlled by the temperature of the surface, which is in turn depend on how much Sun the area gets. Hence, dark units will heat up during the day and appear bright in the infrared. Conversely, visibly bright areas will not heat up as much and will appear dark in the infrared image. The images are centered at 7.1 degrees south latitude and 310.4 degrees east longitude. 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 was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. 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. Credit: NASA/JPL/Arizona State University |
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2001 Mars Odyssey Turns 5
| title |
2001 Mars Odyssey Turns 5 |
| Description |
Five years after leaving Florida for Mars, NASA's Mars Odyssey spacecraft is still orbiting the red planet, collecting scientific data and relaying communications from NASA's two Mars rovers to Earth. Images such as this spectacular, color view of sun-bathed, layered escarpments and wind-scalloped, basalt dunes in the solar system's largest canyon continue to beckon space explorers and guide the way for future missions. Basaltic dunes are common on Mars but rare on Earth. Rounded knobs and mesas on the canyon floor are reminiscent of desert geology in the southwestern U.S. A team led by Phil Christensen, principal investigator for Odyssey's cameras at Arizona State University, Jim Bell at Cornell University, and space artist Don Davis created this panorama. They added color to radiance files from the Thermal Emission Imaging System (THEMIS), a camera on Odyssey that takes images in both the visible and infrared parts of the spectrum. They correlated the radiance - intensity of reflected sunlight - with that of other color images from Mars and mimimized the effects of residual scattered light in the images. In addition to producing images such as this, Mars Odyssey has made global observations of Martian climate, geology, and mineralogy. The spacecraft's Gamma Ray Spectrometer has allowed scientists to make maps of the elemental distribution of hydrogen, silicon, iron, potassium, thorium, and chlorine on the Martian surface. A global map of minerals associated with water, essential to life as we know it, guided NASA in its selection of Meridiani Planum, the landing site for NASA's Opportunity rover, an area rich in hematite. Odyssey is currently supporting landing site selection for the Phoenix Scout Mission, to be launched in 2007, using data showing that surface areas near the poles of Mars consist of more than 50 percent water ice by volume. Other Odyssey accomplishments include measurement of radiation, a prerequisite for future human exploration because of its potential health effects, and a groundbreaking program in education outreach that has allowed students to take pictures of Mars and conduct scientific investigations with cameras on Odyssey. Mars Odyssey was launched April 7, 2001 on a Delta II rocket from Cape Canaveral, Florida, and reached Mars on October 24, 2001. Odyssey employed a technique called "aerobraking" that used the atmosphere of Mars to slow down and gradually bring the spacecraft closer to Mars with each orbit. Odyssey's science mapping mission began in February 2002. The primary science mission continued through August 2004. Odyssey is currently in its extended mission. Credit: NASA/JPL-Caltech/ASU/Cornell/Don Davis |
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Odyssey/White Rock
| title |
Odyssey/White Rock |
| Description |
These Mars Odyssey images show the "White Rock" feature on Mars in both infrared (left) and visible (right) wavelengths. The images were acquired simultaneously on March 11, 2002. The box shows where the visible image is located in the infrared image. "White Rock" is the unofficial name for this unusual landform that was first observed during the Mariner 9 mission in the early 1970's. The variations in brightness in the infrared image are due to differences in surface temperature, where dark is cool and bright is warm. The dramatic differences between the infrared and visible views of White Rock are the result of solar heating. The relatively bright surfaces observed at visible wavelengths reflect more solar energy than the darker surfaces, allowing them to stay cooler and thus they appear dark in the infrared image. The new thermal emission imaging system data will help to address the long standing question of whether the White Rock deposit was produced in an ancient crater lake or by dry processes of volcanic or wind deposition. The infrared image has a resolution of 100 meters (328 feet) per pixel and is 32 kilometers (20 miles) wide. The visible image has a resolution of 18 meters per pixel and is approximately 18 kilometers (11 miles) wide. The images are centered at 8.2 degrees south latitude and 24.9 degrees east longitude. 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 was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. 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. Credit: NASA/JPL/Arizona State University |
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Radiation environment at Mar
…
| title |
Radiation environment at Mars and Earth December 8, 2003 |
| Description |
This graphic shows the radiation dose equivalent as measured by Odyssey's martian radiation environment experiment at Mars and by instruments aboard the Earth-orbiting International Space Station (ISS), for the 18-month period from April 2002 through October 2003. The accumulated total in Mars orbit is just over two times larger than that aboard the Space Station. The bars where the Mars instrument's measurements are well above the average (as shown by the orange line) are months when there was significant solar activity, which increases the dose equivalent. Dose equivalent is expressed in units of milliSieverts per day. NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington. The radiation experiment was provided by the Johnson Space Center, Houston, Texas. Lockheed Martin Space Systems, Denver, Colo., is the prime contractor for the 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. Credit: NASA/JPL/JSC ### |
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The So-Called "Face on Mars
PIA03768
Sol (our sun)
Thermal Emission Imaging Sys
…
| Title |
The So-Called "Face on Mars |
| Original Caption Released with Image |
(Released 13 April 2002) The Science The so called "Face on Mars" can be seen slightly above center and to the right in this THEMIS visible image. This 3-km long knob, located near 10° N, 40° W (320° E), was first imaged by the Viking spacecraft in the 1970's and was seen by some to resemble a face carved into the rocks of Mars. Since that time the Mars Orbiter Camera on the Mars Global Surveyor spacecraft has provided detailed views of this hill that clearly show that it is a normal geologic feature with slopes and ridges carved by eons of wind and downslope motion due to gravity. A similar-size hill in Phoenix, Arizona resembles a camel lying on the ground, and Phoenicians whimsically refer to it as Camelback Mountain. Like the hills and knobs of Mars, however, Camelback Mountain was carved into its unusual shape by thousands of years of erosion. The THEMIS image provides a broad perspective of the landscape in this region, showing numerous knobs and hills that have been eroded into a remarkable array of different shapes. Many of these knobs, including the "Face", have several flat ledges partway up the hill slopes. These ledges are made of more resistant layers of rock and are the last remnants of layers that once were continuous across this entire region. Erosion has completely removed these layers in most places, leaving behind only the small isolated hills and knobs seen today. Many of the hills and ridges in this area also show unusual deposits of material that occur preferentially on the cold, north-facing slopes. It has been suggested that these deposits were "pasted" on the slopes, with the distinct, rounded boundary on their upslope edges being the highest remaining point of this pasted-on layer. In several locations, such as in the large knob directly south of the "Face", these deposits occur at several different heights on the hill. This observation suggests the layer once draped the entire knob and has since been removed from all but the north-facing slopes. The presence of water ice in these layers is a likely possibility to account for their preservation only on the colder surfaces. Alternatively, these unique features could be the result of the slow downslope motion of the surface layer, possibly enhanced by the presence of ground ice. One argument against downslope motion is the observation that the uppermost rounded boundary of these layers typically occurs at approximately the same distance below the ridge crest. This would suggest the (seemingly) unlikely possibility that all of these layers had moved downslope the same amount regardless of where they are located. In either case, ground ice likely plays an important role in the formation and preservation of these deposits because they only occur on the cold slopes facing away from the Sun where ground ice is more stable and may still be present today. The Story Nature is an imaginative artist, creating all kinds of wonderful landforms, cloud shapes, and other patterned, features that remind people of familiar things in our lives. We see a "man in the moon" when it is full in the night sky, and dream of a dromedary-dotted desert when coming upon Arizona's Camelback Mountain or Colorado's "Kissing Camels" in the "Garden of the Gods." Near Ludlow, California, a lonely prospector once noticed that the appealing outline of the mountains resembled a reclining woman, and named the place Sleeping Beauty. And this naming delight isn't limited to Earth. The Mars Pathfinder mission team couldn't help but name the rocks at the landing site, including a bear-headed-looking one named Yogi. Part of the fun of exploration is not just visiting a strange world, but relating to it in human terms. On Mars, we've already seen a valentine heart-shaped crater, a happy-faced crater, and even a murky and mysterious "face" on Mars. This face (seen here about halfway down the image and to the right) is really just a hill with slopes and ridges that are shadowed in a way that can sometimes resemble a face from far away. The first picture of this area was taken by the Viking spacecraft in the 1970s, and people have been intrigued ever since. However, orbiter camera technologies have actually become so good in providing a clear view of the hill that it's almost a disappointment to see how normal an eroded hill this well-liked feature is. Well, disappointing unless you're a geologist, that is! This whole area is, in fact, a geologist's dream. Erosion has been Nature's sculptor throughout the area, and all kinds of remarkably shaped knobs and hills speckle the region. While their shapes are fun to contemplate, it's no mystery to geologists how they formed. Several flat ledges part way up the slopes of these hills are made of layers of rock that stand strong against erosion's relentless carving. Less resistant layers in the region have eroded away completely in most places, leaving behind only the small, isolated hills and knobs we see today. Don?t think everything in this scene is easily understandable, however. What captures the attention of scientists is a bunch of unusual deposits of material on the cold, north-facing slopes of the hills. Did Nature mix some Martian dirt and ice from the planet's "pallet," and then "paste" on a slightly cemented deposit over the northern slopes? Or did an upper layer of material slowly creep downslope over time, carried by the movement of ice? Ground ice, in this case, has probably been more of a preserver than an eroder, keeping a record of the formation and existence of these deposits over time. Geologists are grateful for that peek into the Martian past and the chance to study it in-depth. |
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The So-Called "Face on Mars
PIA03768
Sol (our sun)
Thermal Emission Imaging Sys
…
| Title |
The So-Called "Face on Mars |
| Original Caption Released with Image |
(Released 13 April 2002) The Science The so called "Face on Mars" can be seen slightly above center and to the right in this THEMIS visible image. This 3-km long knob, located near 10° N, 40° W (320° E), was first imaged by the Viking spacecraft in the 1970's and was seen by some to resemble a face carved into the rocks of Mars. Since that time the Mars Orbiter Camera on the Mars Global Surveyor spacecraft has provided detailed views of this hill that clearly show that it is a normal geologic feature with slopes and ridges carved by eons of wind and downslope motion due to gravity. A similar-size hill in Phoenix, Arizona resembles a camel lying on the ground, and Phoenicians whimsically refer to it as Camelback Mountain. Like the hills and knobs of Mars, however, Camelback Mountain was carved into its unusual shape by thousands of years of erosion. The THEMIS image provides a broad perspective of the landscape in this region, showing numerous knobs and hills that have been eroded into a remarkable array of different shapes. Many of these knobs, including the "Face", have several flat ledges partway up the hill slopes. These ledges are made of more resistant layers of rock and are the last remnants of layers that once were continuous across this entire region. Erosion has completely removed these layers in most places, leaving behind only the small isolated hills and knobs seen today. Many of the hills and ridges in this area also show unusual deposits of material that occur preferentially on the cold, north-facing slopes. It has been suggested that these deposits were "pasted" on the slopes, with the distinct, rounded boundary on their upslope edges being the highest remaining point of this pasted-on layer. In several locations, such as in the large knob directly south of the "Face", these deposits occur at several different heights on the hill. This observation suggests the layer once draped the entire knob and has since been removed from all but the north-facing slopes. The presence of water ice in these layers is a likely possibility to account for their preservation only on the colder surfaces. Alternatively, these unique features could be the result of the slow downslope motion of the surface layer, possibly enhanced by the presence of ground ice. One argument against downslope motion is the observation that the uppermost rounded boundary of these layers typically occurs at approximately the same distance below the ridge crest. This would suggest the (seemingly) unlikely possibility that all of these layers had moved downslope the same amount regardless of where they are located. In either case, ground ice likely plays an important role in the formation and preservation of these deposits because they only occur on the cold slopes facing away from the Sun where ground ice is more stable and may still be present today. The Story Nature is an imaginative artist, creating all kinds of wonderful landforms, cloud shapes, and other patterned, features that remind people of familiar things in our lives. We see a "man in the moon" when it is full in the night sky, and dream of a dromedary-dotted desert when coming upon Arizona's Camelback Mountain or Colorado's "Kissing Camels" in the "Garden of the Gods." Near Ludlow, California, a lonely prospector once noticed that the appealing outline of the mountains resembled a reclining woman, and named the place Sleeping Beauty. And this naming delight isn't limited to Earth. The Mars Pathfinder mission team couldn't help but name the rocks at the landing site, including a bear-headed-looking one named Yogi. Part of the fun of exploration is not just visiting a strange world, but relating to it in human terms. On Mars, we've already seen a valentine heart-shaped crater, a happy-faced crater, and even a murky and mysterious "face" on Mars. This face (seen here about halfway down the image and to the right) is really just a hill with slopes and ridges that are shadowed in a way that can sometimes resemble a face from far away. The first picture of this area was taken by the Viking spacecraft in the 1970s, and people have been intrigued ever since. However, orbiter camera technologies have actually become so good in providing a clear view of the hill that it's almost a disappointment to see how normal an eroded hill this well-liked feature is. Well, disappointing unless you're a geologist, that is! This whole area is, in fact, a geologist's dream. Erosion has been Nature's sculptor throughout the area, and all kinds of remarkably shaped knobs and hills speckle the region. While their shapes are fun to contemplate, it's no mystery to geologists how they formed. Several flat ledges part way up the slopes of these hills are made of layers of rock that stand strong against erosion's relentless carving. Less resistant layers in the region have eroded away completely in most places, leaving behind only the small, isolated hills and knobs we see today. Don?t think everything in this scene is easily understandable, however. What captures the attention of scientists is a bunch of unusual deposits of material on the cold, north-facing slopes of the hills. Did Nature mix some Martian dirt and ice from the planet's "pallet," and then "paste" on a slightly cemented deposit over the northern slopes? Or did an upper layer of material slowly creep downslope over time, carried by the movement of ice? Ground ice, in this case, has probably been more of a preserver than an eroder, keeping a record of the formation and existence of these deposits over time. Geologists are grateful for that peek into the Martian past and the chance to study it in-depth. |
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Comparison of Martian Radiat
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PIA04258
Sol (our sun)
Mars Radiation Experiment
| Title |
Comparison of Martian Radiation Environment with International Space Station |
| Original Caption Released with Image |
This graphic shows the radiation dose equivalent as measured by Odyssey's Martian radiation environment experiment at Mars and by instruments aboard the International Space Station, for the 11-month period from April 2002 through February 2003. The accumulated total in Mars orbit is about two and a half times larger than that aboard the Space Station. Averaged over this time period, about 10 percent of the dose equivalent at Mars is due to solar particles, although a 30 percent contribution from solar particles was seen in July 2002, when the sun was particularly active. NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The radiation experiment was provided by the Johnson Space Center, Houston, Tex. Lockheed Martin Astronautics, Denver, Colo., is the prime contractor for the 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. |
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Western Arcadia Planitia
PIA04263
Sol (our sun)
Thermal Emission Imaging Sys
…
| Title |
Western Arcadia Planitia |
| Original Caption Released with Image |
This is a Mars Odyssey visible color image of an unnamed crater in western Arcadia Planitia (near 39 degrees N, 179 degrees E). The crater shows a number of interesting internal and external features that suggest that it has undergone substantial modification since it formed. These features include concentric layers and radial streaks of brighter, redder materials inside the crater, and a heavily degraded rim and ejecta blanket. The patterns inside the crater suggest that material has flowed or slumped towards the center. Other craters with features like this have been seen at both northern and southern mid latitudes The distribution of these kinds of craters suggests the possible influence of surface or subsurface ice in the formation of these enigmatic features. The image was taken on September 29, 2002 during late northern spring. This is an approximate true color image, generated from a long strip of visible red (654 nm), green (540 nm), and blue (425 nm) filter images that were calibrated using a combination of pre-flight measurements and Hubble images of Mars. The colors appear perhaps a bit darker than one might expect, this is most likely because the images were acquired in late afternoon (roughly 4:40 p.m. local solar time) and the low Sun angle results in an overall darker surface. 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 was provided by Arizona State University, Tempe. Lockheed Martin Astronautics, Denver, Colo., is the prime contractor for the 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. |
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Radiation Environment at Mar
…
PIA04909
Sol (our sun)
Mars Radiation Experiment
| Title |
Radiation Environment at Mars and Earth |
| Original Caption Released with Image |
December 8, 2003 This graphic shows the radiation dose equivalent as measured by Odyssey's martian radiation environment experiment at Mars and by instruments aboard the Earth-orbiting International Space Station (ISS), for the 18-month period from April 2002 through October 2003. The accumulated total in Mars orbit is just over two times larger than that aboard the Space Station. The bars where the Mars instrument's measurements are well above the average (as shown by the orange line) are months when there was significant solar activity, which increases the dose equivalent. Dose equivalent is expressed in units of milliSieverts per day. NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington. The radiation experiment was provided by the Johnson Space Center, Houston, Texas. Lockheed Martin Space Systems, Denver, Colo., is the prime contractor for the 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. |
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Northern Arabia Etched Terra
…
PIA03811
Sol (our sun)
Thermal Emission Imaging Sys
…
| Title |
Northern Arabia Etched Terrain |
| Original Caption Released with Image |
(Released 23 May 2002) The Science Many places on Mars display scabby, eroded landscapes that commonly are referred to as etched terrain. These places have a ragged, tortured look that reveals a geologic history of intense deposition and erosion. This THEMIS image shows such a place. Here a 10 km diameter crater is superposed on the floor of a 40 km diameter crater, most of which is outside of the image but apparent in the MOLA context image. The rugged crater rim material intermingles with low, flat-topped mesas and layers with irregular outlines along with dune-like ridges on many of the flat surfaces. The horizontal layers that occur throughout the scene at different elevations are evidence of repeated episodes of deposition. The apparent ease with which these deposits have been eroded, most likely by wind, suggests that they are composed of poorly consolidated material. Air-fall sediments are the likely candidate for this material rather than lava flows. The dune-like ridges are probably inactive granule ripples produced from the interaction of wind and erosional debris. The large interior crater displays features that are the result of deposition and subsequent erosion. Its raised rim is barely discernable due to burial while piles and blocks of slumped material along the interior circumference attest to the action of erosion. Some of the blocks retain the same texture as the surrounding undisrupted surface. It appears as if the crater had been buried long enough for the overlying material to be eroded into the texture seen today. Then at some point this overburden foundered and collapsed into the crater. Continuing erosion has caused the upper layer to retreat back from what was probably the original rim of the crater, producing the noncircular appearance seen today. The length of time represented by this sequence of events as well as the conditions necessary to produce them are unknown. The Story Have you ever seen an ink etching, where the artistic cross-hatching of lines creates the image of a town or a landscape? Click on the large THEMIS image above, and you'll see why this scabby, eroded landscape is known as etched terrain. Etched terrain is found in lots of areas of Mars. These places have a ragged, tortured look that reveals a geologic history where material has been deposited and eroded away with great intensity over time. Much of the terrain looks like peeling, layered-on paint. In a sense, that's what it's all about. Deposits of dust and dirt settled down from the air in layer after uneven layer, while the wind kept eroding it away. Dune-like ridges also mark the surface in tiny ripples. Unlike the loose sand dunes we're familiar with on Earth, these ridges are probably harder and more stationary, They are produced by long-term interactions between the sculpting, knife-like action of the Martian wind and the deposited materials of dust and "dirt" on the surface. What we can also see in this image is a six-mile-wide crater. If, you look at the context image to the right, you can see that it is actually a crater within a crater. The larger crater is about 24 miles wide in diameter. (Students! How many times bigger is the larger crater than the one that lies inside of it? If you look at the context image, you can get a really good sense of what "four times bigger" really means.) What's interesting about this crater is that it doesn't have typical features known to many craters: it isn't nice-and-neatly round and its raised rim is barely noticeable. That's because there's been a whole lot of depositing and eroding going on here too. After the impact crater formed, it was probably entirely buried by deposits over time. In fact, it was probably buried long enough for the overlying material to be eroded into the texture seen today. At some point, the load on top foundered and collapsed into the crater. Around the inside circumference of the crater, you can see piles of slumped material (material that has slid downslope). Some of these blocks of material have the same texture as surrounding terrain that hasn't been disrupted. That's because of continuing erosion acting on all of these features. In the upper layers, continuing erosion has also caused a retreat from the original rim of the crater, producing the noncircular shape seen today. |
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Northern Arabia Etched Terra
…
PIA03811
Sol (our sun)
Thermal Emission Imaging Sys
…
| Title |
Northern Arabia Etched Terrain |
| Original Caption Released with Image |
(Released 23 May 2002) The Science Many places on Mars display scabby, eroded landscapes that commonly are referred to as etched terrain. These places have a ragged, tortured look that reveals a geologic history of intense deposition and erosion. This THEMIS image shows such a place. Here a 10 km diameter crater is superposed on the floor of a 40 km diameter crater, most of which is outside of the image but apparent in the MOLA context image. The rugged crater rim material intermingles with low, flat-topped mesas and layers with irregular outlines along with dune-like ridges on many of the flat surfaces. The horizontal layers that occur throughout the scene at different elevations are evidence of repeated episodes of deposition. The apparent ease with which these deposits have been eroded, most likely by wind, suggests that they are composed of poorly consolidated material. Air-fall sediments are the likely candidate for this material rather than lava flows. The dune-like ridges are probably inactive granule ripples produced from the interaction of wind and erosional debris. The large interior crater displays features that are the result of deposition and subsequent erosion. Its raised rim is barely discernable due to burial while piles and blocks of slumped material along the interior circumference attest to the action of erosion. Some of the blocks retain the same texture as the surrounding undisrupted surface. It appears as if the crater had been buried long enough for the overlying material to be eroded into the texture seen today. Then at some point this overburden foundered and collapsed into the crater. Continuing erosion has caused the upper layer to retreat back from what was probably the original rim of the crater, producing the noncircular appearance seen today. The length of time represented by this sequence of events as well as the conditions necessary to produce them are unknown. The Story Have you ever seen an ink etching, where the artistic cross-hatching of lines creates the image of a town or a landscape? Click on the large THEMIS image above, and you'll see why this scabby, eroded landscape is known as etched terrain. Etched terrain is found in lots of areas of Mars. These places have a ragged, tortured look that reveals a geologic history where material has been deposited and eroded away with great intensity over time. Much of the terrain looks like peeling, layered-on paint. In a sense, that's what it's all about. Deposits of dust and dirt settled down from the air in layer after uneven layer, while the wind kept eroding it away. Dune-like ridges also mark the surface in tiny ripples. Unlike the loose sand dunes we're familiar with on Earth, these ridges are probably harder and more stationary, They are produced by long-term interactions between the sculpting, knife-like action of the Martian wind and the deposited materials of dust and "dirt" on the surface. What we can also see in this image is a six-mile-wide crater. If, you look at the context image to the right, you can see that it is actually a crater within a crater. The larger crater is about 24 miles wide in diameter. (Students! How many times bigger is the larger crater than the one that lies inside of it? If you look at the context image, you can get a really good sense of what "four times bigger" really means.) What's interesting about this crater is that it doesn't have typical features known to many craters: it isn't nice-and-neatly round and its raised rim is barely noticeable. That's because there's been a whole lot of depositing and eroding going on here too. After the impact crater formed, it was probably entirely buried by deposits over time. In fact, it was probably buried long enough for the overlying material to be eroded into the texture seen today. At some point, the load on top foundered and collapsed into the crater. Around the inside circumference of the crater, you can see piles of slumped material (material that has slid downslope). Some of these blocks of material have the same texture as surrounding terrain that hasn't been disrupted. That's because of continuing erosion acting on all of these features. In the upper layers, continuing erosion has also caused a retreat from the original rim of the crater, producing the noncircular shape seen today. |
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South Polar Cap
PIA05606
Sol (our sun)
Thermal Emission Imaging Sys
…
| Title |
South Polar Cap |
| Original Caption Released with Image |
Released 8 March 2004 The Odyssey spacecraft has completed a full Mars year of observations of the red planet. For the next several weeks the Image of the Day will look back over this first mars year. It will focus on four themes: 1) the poles - with the seasonal changes seen in the retreat and expansion of the caps, 2) craters - with a variety of morphologies relating to impact materials and later alteration, both infilling and exhumation, 3) channels - the clues to liquid surface flow, and 4) volcanic flow features. While some images have helped answer questions about the history of Mars, many have raised new questions that are still being investigated as Odyssey continues collecting data as it orbits Mars. This image was collected March 5, 2002 during the southern summer season. Layering in the South polar cap interior is readily visible and may indicate yearly ice/dust deposition. Image information: VIS instrument. Latitude -86.6, Longitude 156.8 East (203.2 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. |
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South Polar Cap
PIA05606
Sol (our sun)
Thermal Emission Imaging Sys
…
| Title |
South Polar Cap |
| Original Caption Released with Image |
Released 8 March 2004 The Odyssey spacecraft has completed a full Mars year of observations of the red planet. For the next several weeks the Image of the Day will look back over this first mars year. It will focus on four themes: 1) the poles - with the seasonal changes seen in the retreat and expansion of the caps, 2) craters - with a variety of morphologies relating to impact materials and later alteration, both infilling and exhumation, 3) channels - the clues to liquid surface flow, and 4) volcanic flow features. While some images have helped answer questions about the history of Mars, many have raised new questions that are still being investigated as Odyssey continues collecting data as it orbits Mars. This image was collected March 5, 2002 during the southern summer season. Layering in the South polar cap interior is readily visible and may indicate yearly ice/dust deposition. Image information: VIS instrument. Latitude -86.6, Longitude 156.8 East (203.2 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. |
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Cerberus Wind Streaks
PIA03789
Sol (our sun)
Thermal Emission Imaging Sys
…
| Title |
Cerberus Wind Streaks |
| Original Caption Released with Image |
(Released 6 May 2002) The Science Cerberus is a dark region on Mars that has shrunk down from a continuous length of about 1000 km to roughly three discontinuous spots a few 100 kms in length in less than 20 years. There are two competing processes at work in the Cerberus region that produce the bright and dark features seen in this THEMIS image. Bright dust settles out of the atmosphere, especially after global dust storms, depositing a layer just thick enough to brighten the dark surfaces. Deposition occurs preferentially in the low wind "shadow zones" within craters and downwind of crater rims, producing the bright streaks. The direction of the streaks clearly indicates that the dominant winds come from the northeast. Dust deposition would completely blot out the dark areas if it were not for the action of wind-blown sand grains scouring the surface and lifting the dust back into the atmosphere. Again, the shadow zones are protected from the blowing sand, preserving the bright layer of dust. Also visible in this image are lava flow features extending from the flanks of the huge Elysium volcanoes to the northwest. Two shallow channels and a raised flow lobe are just barely discernable. The lava channel in the middle of the image crosses the boundary of the bright and dark surfaces without any obvious change in its morphology. This demonstrates that the bright dust layer is very thin in this location, perhaps as little as a few millimeters. The Story Mars is an ever-changing land of spectacular contrasts. This THEMIS image shows the Cerberus region of Mars, a dark area located near the Elysium volcanoes and fittingly named after the three-headed, dragon-tailed dog who guards the door of the underworld. Two opposing processes are at work here: a thin layer of dust falling from the atmosphere and/or dust storms creating brighter surface areas (e.g. the top left portion of this image) and dust being scoured away by the action of the Martian wind disturbing the sand grains and freeing the lighter dust to fly away once more (the darker portions of this image). There are, however, some darker areas that are somewhat shielded and protected from the wind that have yielded bright, dusty crater floors and wind streaks that trail out behind the craters. These wind streaks tell a story all their own as to the prevailing wind direction coming from the northeast. This, added to the fact that this dark region was once 1000 km in length and has dwindled to just a few isolated dark splotches of 100 kilometers in the past 20 years, help us to see that the Martian environment is still quite dynamic and capable of changing. Finally, this being a volcanic region, a lobe of a lava flow from the immense Elysium volcanoes to the northwest is visible stretching across the bottom one-quarter of the image. |
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Cerberus Wind Streaks
PIA03789
Sol (our sun)
Thermal Emission Imaging Sys
…
| Title |
Cerberus Wind Streaks |
| Original Caption Released with Image |
(Released 6 May 2002) The Science Cerberus is a dark region on Mars that has shrunk down from a continuous length of about 1000 km to roughly three discontinuous spots a few 100 kms in length in less than 20 years. There are two competing processes at work in the Cerberus region that produce the bright and dark features seen in this THEMIS image. Bright dust settles out of the atmosphere, especially after global dust storms, depositing a layer just thick enough to brighten the dark surfaces. Deposition occurs preferentially in the low wind "shadow zones" within craters and downwind of crater rims, producing the bright streaks. The direction of the streaks clearly indicates that the dominant winds come from the northeast. Dust deposition would completely blot out the dark areas if it were not for the action of wind-blown sand grains scouring the surface and lifting the dust back into the atmosphere. Again, the shadow zones are protected from the blowing sand, preserving the bright layer of dust. Also visible in this image are lava flow features extending from the flanks of the huge Elysium volcanoes to the northwest. Two shallow channels and a raised flow lobe are just barely discernable. The lava channel in the middle of the image crosses the boundary of the bright and dark surfaces without any obvious change in its morphology. This demonstrates that the bright dust layer is very thin in this location, perhaps as little as a few millimeters. The Story Mars is an ever-changing land of spectacular contrasts. This THEMIS image shows the Cerberus region of Mars, a dark area located near the Elysium volcanoes and fittingly named after the three-headed, dragon-tailed dog who guards the door of the underworld. Two opposing processes are at work here: a thin layer of dust falling from the atmosphere and/or dust storms creating brighter surface areas (e.g. the top left portion of this image) and dust being scoured away by the action of the Martian wind disturbing the sand grains and freeing the lighter dust to fly away once more (the darker portions of this image). There are, however, some darker areas that are somewhat shielded and protected from the wind that have yielded bright, dusty crater floors and wind streaks that trail out behind the craters. These wind streaks tell a story all their own as to the prevailing wind direction coming from the northeast. This, added to the fact that this dark region was once 1000 km in length and has dwindled to just a few isolated dark splotches of 100 kilometers in the past 20 years, help us to see that the Martian environment is still quite dynamic and capable of changing. Finally, this being a volcanic region, a lobe of a lava flow from the immense Elysium volcanoes to the northwest is visible stretching across the bottom one-quarter of the image. |
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Maunder Crater
PIA03812
Sol (our sun)
Thermal Emission Imaging Sys
…
| Title |
Maunder Crater |
| Original Caption Released with Image |
(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-facing slopes in the southern hemisphere of Mars, you can see from this image that they occur on north-facing slopes as well. Comparing where gullies appear will help scientists understand more about the conditions under which they form. Some researchers are really excited about gullies on Mars, because they believe these surface tracings might be signs that groundwater has leaked out of the rock layers on the walls of craters. If that's true, the water runs down the slope and forms the flow-like features seen in the image. Scientists can get into some really hot debates, however. Other researchers think that these features could be formed by other fluids, such as carbon dioxide. No one knows for sure, so a lot of heads will be studiously bent over these images, continuing to study them closely. The neat thing about science is that the way you get closer to the truth is to hypothesize and then test, test, and test again. Debate for scientists is seen as an essential means of making sure that, no wrong assumptions are made or that no important factor is left out. It's what keeps the field interesting and dynamic . . . and sometimes quite loud and entertaining! |
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Maunder Crater
PIA03812
Sol (our sun)
Thermal Emission Imaging Sys
…
| Title |
Maunder Crater |
| Original Caption Released with Image |
(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-facing slopes in the southern hemisphere of Mars, you can see from this image that they occur on north-facing slopes as well. Comparing where gullies appear will help scientists understand more about the conditions under which they form. Some researchers are really excited about gullies on Mars, because they believe these surface tracings might be signs that groundwater has leaked out of the rock layers on the walls of craters. If that's true, the water runs down the slope and forms the flow-like features seen in the image. Scientists can get into some really hot debates, however. Other researchers think that these features could be formed by other fluids, such as carbon dioxide. No one knows for sure, so a lot of heads will be studiously bent over these images, continuing to study them closely. The neat thing about science is that the way you get closer to the truth is to hypothesize and then test, test, and test again. Debate for scientists is seen as an essential means of making sure that, no wrong assumptions are made or that no important factor is left out. It's what keeps the field interesting and dynamic . . . and sometimes quite loud and entertaining! |
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Tharsis Rise Graben
PIA03810
Sol (our sun)
Thermal Emission Imaging Sys
…
| Title |
Tharsis Rise Graben |
| Original Caption Released with Image |
(Released 22 May 2002) The Science This image is located in the northwestern portion of the Tharsis Rise at about 12 N and 125 W (235 E). What is immediately noticeable in this image is the series of linear features that are called graben. These features are associated with crustal extension which results in a series of up and down blocks of crust that run perpendicular to the direction of the extension. Images of Mars have shown a large number of these tectonic features concentrated on or near the Tharsis region. The Tharsis region is an enormous bulge that causes major tectonic disruptions across the planet when it tries to settle down from its height and reach equilibrium with the rest of the planet. The graben in this image display a number of preferential directions indicating that the crustal stresses that caused the graben have changed over time. By examining the cross-cutting relationships between the features, it is possible to reassemble the history of the area. The Story Now, if you thought that Mars was almost perfectly round, think again! The red planet has a large bulge sticking out from it called Tharsis. Almost 3,000 miles across, this enormous region rises almost four miles above the average radius of the planet. That's quite a bulge! Since Tharsis the land of the largest volcanoes in the solar system, it may have been formed by both the uplift of land from tectonic action and the build-up of lava flows. Tharsis can cause some pretty major tectonic disruptions across the planet when it tries to settle down from its height and reach a better equilibrium with the rest of the planet. In this image, located in the northwestern portion of the Tharsis Rise, a whole lot of lowered features stripe the landscape. They are called grabens, and formed when the crust of the planet was stretched tectonically. This kind of crustal extension (or stretching) tends to form a series of up-and-down blocks of crust that run perpendicular to the direction of the crustal extension. And that's what we see here. Since the streaks (or grabens) in this image aren't all perfectly aligned, that means that the crustal stresses and their directions have changed over time. And there's another history to be followed here too. Take a look at how some of the grabens cut across others. Those that cross on top of others had to have formed after the ones underneath. By looking at all of the crosscutting relationships, geologists can build up a pretty accurate record of which stresses happened first, next, and last. On Earth, a similar series of rift valleys (grabens) formed by crustal extension too. The East African Rift System began forming almost 30 million years ago due to volcanic activity that also created most of the high peaks in East Africa, including the famous Kilimanjaro. This African peak is so high it always has snow on top of it, even though it's located right near the equator. That height might remind you of the towering Martian volcanoes in, Tharsis. The East African Rift Valley System also formed over large domes that were created as hot molten material beneath the Earth's surface welled up, pushing up the crust and causing it to expand and stretch. This stretching caused the rift valleys (grabens) to appear here on our own planet. |
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Tharsis Rise Graben
PIA03810
Sol (our sun)
Thermal Emission Imaging Sys
…
| Title |
Tharsis Rise Graben |
| Original Caption Released with Image |
(Released 22 May 2002) The Science This image is located in the northwestern portion of the Tharsis Rise at about 12 N and 125 W (235 E). What is immediately noticeable in this image is the series of linear features that are called graben. These features are associated with crustal extension which results in a series of up and down blocks of crust that run perpendicular to the direction of the extension. Images of Mars have shown a large number of these tectonic features concentrated on or near the Tharsis region. The Tharsis region is an enormous bulge that causes major tectonic disruptions across the planet when it tries to settle down from its height and reach equilibrium with the rest of the planet. The graben in this image display a number of preferential directions indicating that the crustal stresses that caused the graben have changed over time. By examining the cross-cutting relationships between the features, it is possible to reassemble the history of the area. The Story Now, if you thought that Mars was almost perfectly round, think again! The red planet has a large bulge sticking out from it called Tharsis. Almost 3,000 miles across, this enormous region rises almost four miles above the average radius of the planet. That's quite a bulge! Since Tharsis the land of the largest volcanoes in the solar system, it may have been formed by both the uplift of land from tectonic action and the build-up of lava flows. Tharsis can cause some pretty major tectonic disruptions across the planet when it tries to settle down from its height and reach a better equilibrium with the rest of the planet. In this image, located in the northwestern portion of the Tharsis Rise, a whole lot of lowered features stripe the landscape. They are called grabens, and formed when the crust of the planet was stretched tectonically. This kind of crustal extension (or stretching) tends to form a series of up-and-down blocks of crust that run perpendicular to the direction of the crustal extension. And that's what we see here. Since the streaks (or grabens) in this image aren't all perfectly aligned, that means that the crustal stresses and their directions have changed over time. And there's another history to be followed here too. Take a look at how some of the grabens cut across others. Those that cross on top of others had to have formed after the ones underneath. By looking at all of the crosscutting relationships, geologists can build up a pretty accurate record of which stresses happened first, next, and last. On Earth, a similar series of rift valleys (grabens) formed by crustal extension too. The East African Rift System began forming almost 30 million years ago due to volcanic activity that also created most of the high peaks in East Africa, including the famous Kilimanjaro. This African peak is so high it always has snow on top of it, even though it's located right near the equator. That height might remind you of the towering Martian volcanoes in, Tharsis. The East African Rift Valley System also formed over large domes that were created as hot molten material beneath the Earth's surface welled up, pushing up the crust and causing it to expand and stretch. This stretching caused the rift valleys (grabens) to appear here on our own planet. |
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Floor of Juventae Chasma
PIA03818
Sol (our sun)
Thermal Emission Imaging Sys
…
| Title |
Floor of Juventae Chasma |
| Original Caption Released with Image |
(Released 30 May 2002) Juventae Chasma is an enormous box canyon (250 km X 100 km) which opens to the north and forms the outflow channel Maja Vallis. Most Martian outflow channels such as Maja, Kasei, and Ares Valles begin at point sources such as box canyons and chaotic terrain and then flow unconfined into a basin region. This image captures a portion of the western floor of Juventae Chasma and shows a wide variety of landforms. Conical hills, mesas, buttes and plateaus of layered material dominate this scene and seem to be "swimming" in vast sand sheets. The conical hills have a spur and gully topography associated with them while the flat topped buttes and mesas do not. This may be indicative of different materials that compose each of these landforms or it could be that the flat-topped layer has been completely eroded off of the conical hills thereby exposing a different rock type. Both the conical hills and flat-topped buttes and mesas have extensive scree slopes (heaps of eroded rock and debris). Ripples, which are inferred to be dunes, can also be seen amongst the hills. No impact craters can be seen in this image, indicating that the erosion and transport of material down the canyon wall and across the floor is occurring at a relatively rapid rate, so that any craters that form are rapidly buried or eroded. |
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Floor of Juventae Chasma
PIA03818
Sol (our sun)
Thermal Emission Imaging Sys
…
| Title |
Floor of Juventae Chasma |
| Original Caption Released with Image |
(Released 30 May 2002) Juventae Chasma is an enormous box canyon (250 km X 100 km) which opens to the north and forms the outflow channel Maja Vallis. Most Martian outflow channels such as Maja, Kasei, and Ares Valles begin at point sources such as box canyons and chaotic terrain and then flow unconfined into a basin region. This image captures a portion of the western floor of Juventae Chasma and shows a wide variety of landforms. Conical hills, mesas, buttes and plateaus of layered material dominate this scene and seem to be "swimming" in vast sand sheets. The conical hills have a spur and gully topography associated with them while the flat topped buttes and mesas do not. This may be indicative of different materials that compose each of these landforms or it could be that the flat-topped layer has been completely eroded off of the conical hills thereby exposing a different rock type. Both the conical hills and flat-topped buttes and mesas have extensive scree slopes (heaps of eroded rock and debris). Ripples, which are inferred to be dunes, can also be seen amongst the hills. No impact craters can be seen in this image, indicating that the erosion and transport of material down the canyon wall and across the floor is occurring at a relatively rapid rate, so that any craters that form are rapidly buried or eroded. |
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Gullies of Gorgonus Chaos
PIA03826
Sol (our sun)
Thermal Emission Imaging Sys
…
| Title |
Gullies of Gorgonus Chaos |
| Original Caption Released with Image |
(Released 11 June 2002) The Science This fractured surface belongs to a portion of a region called Gorgonum Chaos located in the southern hemisphere of Mars. Gorgonum Chaos is named after the Gorgons in ancient Greek mythology. The Gorgons were monstrous sisters with snakes for hair, tusks like boars and lolling tongues who lived in caves. As it turns out this is indeed a fitting name for this region of Mars because it contains a high density of gullies that "snake" their way down the walls of the troughs located in this region of chaos. Upon closer examination one finds that these gullies and alluvial deposits, initially discovered by Mars Global Surveyor, are visible on the trough walls (best seen near the bottom of the image). These gullies appear to emanate from a specific layer in the walls. The gullies have been proposed to have formed by the subsurface release of water. The Story This fractured, almost spooky-looking surface belongs to a region called Gorgonum Chaos in the southern hemisphere of Mars. Chaos is a term used for regions of Mars with distinctive areas of broken terrain like the one seen above. This area of Martian chaos is named after the Gorgons in ancient Greek mythology. The Gorgons were monstrous sisters with snakes for hair, tusks like boars, and lolling tongues, who lived in caves. The Gorgons, including famous sister Medusa, could turn a person to stone, and their writhing, snakelike locks cause revulsion to this day. Given the afflicted nature of this contorted terrain, with all of its twisted, branching channels and hard, stony-looking hills in the top half of the image, this is indeed a fitting name for this region of Mars. The name also has great appeal, because the area contains a high density of gullies that "snake" their way down the walls of the troughs located in this region of Martian chaos. Gullies are trenches cut into the land as accelerated streams of water (or another liquid) erode the surface. To see these, click on the above image to get a high-resolution view, and then focus on the trenches at the bottom. Running down the walls of the trough are the thin, dark lines of the gullies. Beneath the grooved, gully channels are faint, softer-looking fans of material. These are called alluvial deposits. Alluvial simply means all of the sand, gravel, and dirt that is carried and deposited by a liquid. On Earth, that liquid is typically water. As the liquid carves the gully, the eroded material from the channels get carried along and deposited below in fan-like shapes. These gully features were initially discovered by Odyssey's sister orbiter, Mars Global Surveyor, and caused quite a bit of emotional chaos in the scientific community when they were announced. Why? If you look closely, you can see that the gullies seem to form from a specific layer in the wall. That is, they all seem to begin at roughly the same point on the wall. That suggests that maybe, just maybe, there's a subsurface source of water at, that layer that sometimes leaks out and runs down the walls to form both the gullies and the skirt-like fans of deposits beneath them. Other scientists, however, loudly assert that another liquid besides water could have carved the gullies. The debate sometimes gets so intense, you'd think that the opposing sides would want to turn each other's ideas to stone! But not for long. While the debate rages on, the neat thing is that everyone's really united. The goal is to find out, and the way to find out is to keep proposing different hypotheses and testing them out. That's the excitement of science, where everyone's solid research counts, and divergent views are appreciated for keeping science sound. |
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Gullies of Gorgonus Chaos
PIA03826
Sol (our sun)
Thermal Emission Imaging Sys
…
| Title |
Gullies of Gorgonus Chaos |
| Original Caption Released with Image |
(Released 11 June 2002) The Science This fractured surface belongs to a portion of a region called Gorgonum Chaos located in the southern hemisphere of Mars. Gorgonum Chaos is named after the Gorgons in ancient Greek mythology. The Gorgons were monstrous sisters with snakes for hair, tusks like boars and lolling tongues who lived in caves. As it turns out this is indeed a fitting name for this region of Mars because it contains a high density of gullies that "snake" their way down the walls of the troughs located in this region of chaos. Upon closer examination one finds that these gullies and alluvial deposits, initially discovered by Mars Global Surveyor, are visible on the trough walls (best seen near the bottom of the image). These gullies appear to emanate from a specific layer in the walls. The gullies have been proposed to have formed by the subsurface release of water. The Story This fractured, almost spooky-looking surface belongs to a region called Gorgonum Chaos in the southern hemisphere of Mars. Chaos is a term used for regions of Mars with distinctive areas of broken terrain like the one seen above. This area of Martian chaos is named after the Gorgons in ancient Greek mythology. The Gorgons were monstrous sisters with snakes for hair, tusks like boars, and lolling tongues, who lived in caves. The Gorgons, including famous sister Medusa, could turn a person to stone, and their writhing, snakelike locks cause revulsion to this day. Given the afflicted nature of this contorted terrain, with all of its twisted, branching channels and hard, stony-looking hills in the top half of the image, this is indeed a fitting name for this region of Mars. The name also has great appeal, because the area contains a high density of gullies that "snake" their way down the walls of the troughs located in this region of Martian chaos. Gullies are trenches cut into the land as accelerated streams of water (or another liquid) erode the surface. To see these, click on the above image to get a high-resolution view, and then focus on the trenches at the bottom. Running down the walls of the trough are the thin, dark lines of the gullies. Beneath the grooved, gully channels are faint, softer-looking fans of material. These are called alluvial deposits. Alluvial simply means all of the sand, gravel, and dirt that is carried and deposited by a liquid. On Earth, that liquid is typically water. As the liquid carves the gully, the eroded material from the channels get carried along and deposited below in fan-like shapes. These gully features were initially discovered by Odyssey's sister orbiter, Mars Global Surveyor, and caused quite a bit of emotional chaos in the scientific community when they were announced. Why? If you look closely, you can see that the gullies seem to form from a specific layer in the wall. That is, they all seem to begin at roughly the same point on the wall. That suggests that maybe, just maybe, there's a subsurface source of water at, that layer that sometimes leaks out and runs down the walls to form both the gullies and the skirt-like fans of deposits beneath them. Other scientists, however, loudly assert that another liquid besides water could have carved the gullies. The debate sometimes gets so intense, you'd think that the opposing sides would want to turn each other's ideas to stone! But not for long. While the debate rages on, the neat thing is that everyone's really united. The goal is to find out, and the way to find out is to keep proposing different hypotheses and testing them out. That's the excitement of science, where everyone's solid research counts, and divergent views are appreciated for keeping science sound. |
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Wrinkle Ridges and Young Fre
…
PIA03793
Sol (our sun)
Thermal Emission Imaging Sys
…
| Title |
Wrinkle Ridges and Young Fresh Crater |
| Original Caption Released with Image |
(Released 10 May 2002) The Science Wrinkle ridges are a very common landform on Mars, Mercury, Venus, and the Moon. These ridges are linear to arcuate asymmetric topographic highs commonly found on smooth plains. The origin of wrinkle ridges is not certain and two leading hypotheses have been put forth by scientists over the past 40 years. The volcanic model calls for the extrusion of high viscosity lavas along linear conduits. This thick lava accumulated over these conduits and formed the ridges. The other model is tectonic and advocates that the ridges are formed by compressional faulting and folding. Today's THEMIS image is of the ridged plains of Lunae Planum located between Kasei Valles and Valles Marineris in the northern hemisphere of the planet. Wrinkle ridges are found mostly along the eastern side of the image. The broadest wrinkle ridges in this image are up to 2 km wide. A 3 km diameter young fresh crater is located near the bottom of the image. The crater's ejecta blanket is also clearly seen surrounding the sharp well-defined crater rim. These features are indicative of a very young crater that has not been subjected to erosional processes. The Story The great thing about the solar system is that planets are both alike and different. They're all foreign enough to be mysterious and intriguing, and yet familiar enough to be seen as planetary "cousins." By comparing them, we can learn a lot about how planets form and then evolve geologically over time. Crinkled over smooth plains, the long, wavy raised landforms seen here are called "wrinkle ridges," and they've been found on Mars, Mercury, Venus, and the Moon - that is, on rocky bodies that are a part of our inner solar system. We know from this observation that planets (and large-enough moons) follow similar processes. What we don't know for sure is HOW these processes work. Scientists have been trying to understand how wrinkle ridges form for 40 years, and they still haven't reached a conclusion. That's the excitement of science, as the scientific hypotheses and debates continue. Geologists have narrowed down the possibilities to two likely candidates. On the one hand, a volcano could have sent thick streams of lava out that later hardened to form the ridges. On the other, a crushing tectonic force could have pushed the land together, causing it to fault and fold upward. Whichever theory is true, we do know the planet has been subjected to some tremendously active geologic shaping in its past. Don't miss the nearly perfect crater near the bottom of the image. Its sharp crater rim tells us that it is probably pretty young as craters go, because erosion hasn't dulled its edges. Bright material also seems to form a dusty, hazy halo around it. That's all of the material that was blasted out of the crater and sprinkled back down around it in an "ejecta blanket." Seeing it so clearly, seemingly untouched by erosion, also indicates the crater's relative youth. |
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Wrinkle Ridges and Young Fre
…
PIA03793
Sol (our sun)
Thermal Emission Imaging Sys
…
| Title |
Wrinkle Ridges and Young Fresh Crater |
| Original Caption Released with Image |
(Released 10 May 2002) The Science Wrinkle ridges are a very common landform on Mars, Mercury, Venus, and the Moon. These ridges are linear to arcuate asymmetric topographic highs commonly found on smooth plains. The origin of wrinkle ridges is not certain and two leading hypotheses have been put forth by scientists over the past 40 years. The volcanic model calls for the extrusion of high viscosity lavas along linear conduits. This thick lava accumulated over these conduits and formed the ridges. The other model is tectonic and advocates that the ridges are formed by compressional faulting and folding. Today's THEMIS image is of the ridged plains of Lunae Planum located between Kasei Valles and Valles Marineris in the northern hemisphere of the planet. Wrinkle ridges are found mostly along the eastern side of the image. The broadest wrinkle ridges in this image are up to 2 km wide. A 3 km diameter young fresh crater is located near the bottom of the image. The crater's ejecta blanket is also clearly seen surrounding the sharp well-defined crater rim. These features are indicative of a very young crater that has not been subjected to erosional processes. The Story The great thing about the solar system is that planets are both alike and different. They're all foreign enough to be mysterious and intriguing, and yet familiar enough to be seen as planetary "cousins." By comparing them, we can learn a lot about how planets form and then evolve geologically over time. Crinkled over smooth plains, the long, wavy raised landforms seen here are called "wrinkle ridges," and they've been found on Mars, Mercury, Venus, and the Moon - that is, on rocky bodies that are a part of our inner solar system. We know from this observation that planets (and large-enough moons) follow similar processes. What we don't know for sure is HOW these processes work. Scientists have been trying to understand how wrinkle ridges form for 40 years, and they still haven't reached a conclusion. That's the excitement of science, as the scientific hypotheses and debates continue. Geologists have narrowed down the possibilities to two likely candidates. On the one hand, a volcano could have sent thick streams of lava out that later hardened to form the ridges. On the other, a crushing tectonic force could have pushed the land together, causing it to fault and fold upward. Whichever theory is true, we do know the planet has been subjected to some tremendously active geologic shaping in its past. Don't miss the nearly perfect crater near the bottom of the image. Its sharp crater rim tells us that it is probably pretty young as craters go, because erosion hasn't dulled its edges. Bright material also seems to form a dusty, hazy halo around it. That's all of the material that was blasted out of the crater and sprinkled back down around it in an "ejecta blanket." Seeing it so clearly, seemingly untouched by erosion, also indicates the crater's relative youth. |
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Auqakuh Valles
PIA03824
Sol (our sun)
Thermal Emission Imaging Sys
…
| Title |
Auqakuh Valles |
| Original Caption Released with Image |
(Released 7 June 2002) The Science This ancient sinuous river channel, located near 30° N, 299° W (61° E), was likely carved by water early in Mars history. Auqakuh Valles cuts through a remarkable series of rock layers that were deposited and then subsequently eroded. This change from conditions favoring deposition to those favoring erosion indicates that the environment of this region has changed significantly over time. In addition, the different rock layers seen in this image vary in hardness, with some being relatively soft and easily eroded, whereas others are harder and resistant. These differences imply that these layers vary in their composition, physical properties, and/or degree of cementation, and again suggest that major changes have occurred during the history of this region. Similar differences occur throughout the southwest U.S., where hard rock layers, such as the limestones and sandstones in the Grand Canyon, form resistant cliffs, whereas softer mudstones are easily eroded to form broad slopes. The Martian layers, such as the smooth, dark-toned mesas visible in numerous places to the right (east) of the channel, were once continuous across the region. As these layers have eroded, they have produced a wide array of textures, from smooth surfaces, to knobby terrains, to the unusual lobate patterns seen in the upper right of the image. The most recent activity in the region appears to be the formation of mega-ripples by the wind. These ripples, spaced approximately 75 m apart, form perpendicular to the wind direction, and can be seen following the pattern of the channel floor as it curves through this region. This pattern shows that even this relatively small channel, which varies in width from about 500 to 750 m throughout this image, acts to funnel the wind down the channel. The Story Auqakuh Vallis, an ancient river channel that winds its way down the center of this image, is the "fossil" remains of an earlier, probably more watery time in Martian history. Now, you might think that Auqakuh has something to do with Aqua, the Latin word for water. Instead, Auqakuh is the word for Mars in the Quechuan language of the Incan Empire that once stretched across vast portions of South America. This Inca-honoring river channel cuts through a remarkable series of rock layers that expose a history of climate change in the region. The coarse, rugged, and wildly textured terrain was created as rock layers were first deposited, then eroded over time. Some of the rock layers are soft and easily eroded, while others are clearly harder and more resistant. From these differences, geologists can tell that the layers are made up of different materials, have different physical characteristics, and are either loosely or strongly cemented together. That suggests major environmental changes over time as well, since different kinds of rocks form under different conditions. Similar differences in rock layers occur throughout the Southwest of the, United States. The next time you're visiting the Grand Canyon or hiking in similar terrain, notice where hard rock layers, such as limestones and sandstones, form resistant cliffs, whereas softer mudstones are easily eroded to form broad slopes along the canyon. Just in case the river channel in the above image looks more like a raised vein rather than a hollowed out channel, try looking at the half-circle depression on the left-hand side of the image, about a third of the way up. The bright features on the upper half streak down toward the bottom of the bowl. Once you focus on this for a while, your brain figures out that the channel must be depressed as well. Now that you can see that the channel cuts into the surface, click on the image for a closer look at the bottom of the channel. Mega-ripples about 82 yards apart line the channel floor as it curves through the region. This pattern shows that even this relatively small channel, which varies from about one-third to a half of a mile in width, funnels the wind down its curving length, creating perpendicular piles of waving texture on the channel's floor. East of the channel, smooth, dark-toned mesas are visible, providing a scant reminder that they were once continuous across the region. As these layers have eroded, they've produced a wide array of textures, from smooth surfaces, to knobby terrains, to the unusual curved, lobe-like patterns seen in the upper right of the image. |
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Auqakuh Valles
PIA03824
Sol (our sun)
Thermal Emission Imaging Sys
…
| Title |
Auqakuh Valles |
| Original Caption Released with Image |
(Released 7 June 2002) The Science This ancient sinuous river channel, located near 30° N, 299° W (61° E), was likely carved by water early in Mars history. Auqakuh Valles cuts through a remarkable series of rock layers that were deposited and then subsequently eroded. This change from conditions favoring deposition to those favoring erosion indicates that the environment of this region has changed significantly over time. In addition, the different rock layers seen in this image vary in hardness, with some being relatively soft and easily eroded, whereas others are harder and resistant. These differences imply that these layers vary in their composition, physical properties, and/or degree of cementation, and again suggest that major changes have occurred during the history of this region. Similar differences occur throughout the southwest U.S., where hard rock layers, such as the limestones and sandstones in the Grand Canyon, form resistant cliffs, whereas softer mudstones are easily eroded to form broad slopes. The Martian layers, such as the smooth, dark-toned mesas visible in numerous places to the right (east) of the channel, were once continuous across the region. As these layers have eroded, they have produced a wide array of textures, from smooth surfaces, to knobby terrains, to the unusual lobate patterns seen in the upper right of the image. The most recent activity in the region appears to be the formation of mega-ripples by the wind. These ripples, spaced approximately 75 m apart, form perpendicular to the wind direction, and can be seen following the pattern of the channel floor as it curves through this region. This pattern shows that even this relatively small channel, which varies in width from about 500 to 750 m throughout this image, acts to funnel the wind down the channel. The Story Auqakuh Vallis, an ancient river channel that winds its way down the center of this image, is the "fossil" remains of an earlier, probably more watery time in Martian history. Now, you might think that Auqakuh has something to do with Aqua, the Latin word for water. Instead, Auqakuh is the word for Mars in the Quechuan language of the Incan Empire that once stretched across vast portions of South America. This Inca-honoring river channel cuts through a remarkable series of rock layers that expose a history of climate change in the region. The coarse, rugged, and wildly textured terrain was created as rock layers were first deposited, then eroded over time. Some of the rock layers are soft and easily eroded, while others are clearly harder and more resistant. From these differences, geologists can tell that the layers are made up of different materials, have different physical characteristics, and are either loosely or strongly cemented together. That suggests major environmental changes over time as well, since different kinds of rocks form under different conditions. Similar differences in rock layers occur throughout the Southwest of the, United States. The next time you're visiting the Grand Canyon or hiking in similar terrain, notice where hard rock layers, such as limestones and sandstones, form resistant cliffs, whereas softer mudstones are easily eroded to form broad slopes along the canyon. Just in case the river channel in the above image looks more like a raised vein rather than a hollowed out channel, try looking at the half-circle depression on the left-hand side of the image, about a third of the way up. The bright features on the upper half streak down toward the bottom of the bowl. Once you focus on this for a while, your brain figures out that the channel must be depressed as well. Now that you can see that the channel cuts into the surface, click on the image for a closer look at the bottom of the channel. Mega-ripples about 82 yards apart line the channel floor as it curves through the region. This pattern shows that even this relatively small channel, which varies from about one-third to a half of a mile in width, funnels the wind down its curving length, creating perpendicular piles of waving texture on the channel's floor. East of the channel, smooth, dark-toned mesas are visible, providing a scant reminder that they were once continuous across the region. As these layers have eroded, they've produced a wide array of textures, from smooth surfaces, to knobby terrains, to the unusual curved, lobe-like patterns seen in the upper right of the image. |
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Mangala Fossa
PIA03815
Sol (our sun)
Thermal Emission Imaging Sys
…
| Title |
Mangala Fossa |
| Original Caption Released with Image |
(Released 29 May 2002) The Science Today's THEMIS release captures Mangala Fossa. Mangala Fossa is a graben, which in geologic terminology translates into a long parallel to semi-parallel fracture or trough. Grabens are dropped or downthrown areas relative to the rocks on either side and these features are generally longer than they are wider. There are numerous dust devil trails seen in this image. In the lower portion of this image several dust devil tracks can be seen cutting across the upper surface then down the short stubby channel and finally back up and over to the adjacent upper surface. Some dust avalanche streaks on slopes are also visible. The rough material in the upper third of the image contains a portion of the rim of a 90 km diameter crater located in Daedalia Planum. The smooth crater floor has a graben (up to 7 km wide) and channel (2 km wide) incised into its surface. In the middle third and right of this image one can see ripples (possibly fossil dunes) on the crater floor material just above the graben. The floor of Mangala Fossa and the southern crater floor surface also have smaller linear ridges trending from the upper left to lower right. These linear ridges could be either erosional (yardangs) or depositional (dunes) landforms. The lower third of the scene contains a short stubby channel (near the right margin) and lava flow front (lower left). The floor of this channel is fairly smooth with some linear crevasses located along its course. One gets the impression that the channel floor is mantled with some type of indurated material that permits cracks to form in its surface. The Story In the Daedalia Plains on Mars, the rim of an old eroded crater rises up, a wreck of its former self (see context image at right). From the rough, choppy crater rim (top of the larger THEMIS image), the terrain descends to the almost smooth crater floor, gouged deeply by a trough, a channel, and the occasional dents of small, scattered craters. The deep trough running from southwest to northeast across the middle of this image is called "Mangala Fossa." Mangala Fossa is a graben, a land feature created by tectonic processes that worked to create a depression in the landscape. This graben is a little more than 4 miles wide at its maximum, but like most grabens, is much longer than it is wide. You can see from the context image that it runs across much of the width of the crater. Running southward from the graben (lower right-hand side of the larger THEMIS image) is a branching channel a little over a mile wide. The floor of this channel is fairly smooth with some linear crevasses along its course. These features suggest that the channel floor might be layered with some type of cemented material that permits cracks to form in its surface. Between the rough crater rim and the depressed graben, tiny crackles on the otherwise smooth surface appear. They might be the ripples of fossil dunes, hardened remains from a more active time. The, floor of Mangala Fossa and the southern crater floor surface also feature small lines that seem to crease the surface. We know that they are ridges on the surface, but how did they form? Were higher surfaces carved away in grooves by the wind and scouring sand, forming ridges called yardangs? Or were dunes deposited on the smooth, lower terrain? No one knows for sure. Look closely for faint details as well. Do you see the subtle, scalloped pattern that laps at the lower left of the image, almost too muted to be seen? That's the sign of an ancient lava flow that stopped just there. And the shadowy gray streaks? Some are smudges caused by dust avalanches running down the slopes of the channel. Others are the tracks of dust devils that pass across the land, lifting and carrying away brighter dust to reveal the darker surface beneath. For a good example of a dust devil track, check out the faint gray line that cuts across the upper part of the channel, just below the point where it meets the graben. |
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Mangala Fossa
PIA03815
Sol (our sun)
Thermal Emission Imaging Sys
…
| Title |
Mangala Fossa |
| Original Caption Released with Image |
(Released 29 May 2002) The Science Today's THEMIS release captures Mangala Fossa. Mangala Fossa is a graben, which in geologic terminology translates into a long parallel to semi-parallel fracture or trough. Grabens are dropped or downthrown areas relative to the rocks on either side and these features are generally longer than they are wider. There are numerous dust devil trails seen in this image. In the lower portion of this image several dust devil tracks can be seen cutting across the upper surface then down the short stubby channel and finally back up and over to the adjacent upper surface. Some dust avalanche streaks on slopes are also visible. The rough material in the upper third of the image contains a portion of the rim of a 90 km diameter crater located in Daedalia Planum. The smooth crater floor has a graben (up to 7 km wide) and channel (2 km wide) incised into its surface. In the middle third and right of this image one can see ripples (possibly fossil dunes) on the crater floor material just above the graben. The floor of Mangala Fossa and the southern crater floor surface also have smaller linear ridges trending from the upper left to lower right. These linear ridges could be either erosional (yardangs) or depositional (dunes) landforms. The lower third of the scene contains a short stubby channel (near the right margin) and lava flow front (lower left). The floor of this channel is fairly smooth with some linear crevasses located along its course. One gets the impression that the channel floor is mantled with some type of indurated material that permits cracks to form in its surface. The Story In the Daedalia Plains on Mars, the rim of an old eroded crater rises up, a wreck of its former self (see context image at right). From the rough, choppy crater rim (top of the larger THEMIS image), the terrain descends to the almost smooth crater floor, gouged deeply by a trough, a channel, and the occasional dents of small, scattered craters. The deep trough running from southwest to northeast across the middle of this image is called "Mangala Fossa." Mangala Fossa is a graben, a land feature created by tectonic processes that worked to create a depression in the landscape. This graben is a little more than 4 miles wide at its maximum, but like most grabens, is much longer than it is wide. You can see from the context image that it runs across much of the width of the crater. Running southward from the graben (lower right-hand side of the larger THEMIS image) is a branching channel a little over a mile wide. The floor of this channel is fairly smooth with some linear crevasses along its course. These features suggest that the channel floor might be layered with some type of cemented material that permits cracks to form in its surface. Between the rough crater rim and the depressed graben, tiny crackles on the otherwise smooth surface appear. They might be the ripples of fossil dunes, hardened remains from a more active time. The, floor of Mangala Fossa and the southern crater floor surface also feature small lines that seem to crease the surface. We know that they are ridges on the surface, but how did they form? Were higher surfaces carved away in grooves by the wind and scouring sand, forming ridges called yardangs? Or were dunes deposited on the smooth, lower terrain? No one knows for sure. Look closely for faint details as well. Do you see the subtle, scalloped pattern that laps at the lower left of the image, almost too muted to be seen? That's the sign of an ancient lava flow that stopped just there. And the shadowy gray streaks? Some are smudges caused by dust avalanches running down the slopes of the channel. Others are the tracks of dust devils that pass across the land, lifting and carrying away brighter dust to reveal the darker surface beneath. For a good example of a dust devil track, check out the faint gray line that cuts across the upper part of the channel, just below the point where it meets the graben. |
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Lava Flows in Eastern Tharsi
…
PIA03819
Sol (our sun)
Thermal Emission Imaging Sys
…
| Title |
Lava Flows in Eastern Tharsis |
| Original Caption Released with Image |
(Released 31 May 2002) This image may at first appear somewhat bland -- there is little contrast in the surface materials due to dust cover, and there are few impact craters -- but there are some very interesting geologic features here. The great Tharsis volcanoes have produced vast fields of lava flows, such as those shown in this image, to the east of Tharsis Tholus. The flows in this image have moved from west to east, down the regional topographic slope. The lobate edges of the flows are distinctive, and permit the discrimination of many overlapping individual flows that may represent tens, hundreds, thousands, or even millions of years worth of volcanic activity (overlapping relationships are especially evident at the bottom of the image). Viewed at full resolution, the image reveals interesting patterns and textures on the top surfaces of these flows. In particular, at the top of the image, there are numerous parallel curved ridges visible on the upper surfaces of the lava flows. These ridges make the flow surface look somewhat ropy, and at smaller scales this flow might be referred to as pahoehoe, indicative of a relatively fluid type of lava flow. At the scales observed here, however, these features are probably better referred to as pressure ridges. Pressure ridges form on the surface of a lava flow when the upper part of the flow is exposed to air, freezing it, but the insulated unfrozen interior of the flow continues to move down slope (and more material is pushed forward from behind), causing the surface to compress and pile up like a rug. Rough-looking flows with less distinct (more random) patterns on their surfaces may be flows that are more like terrestrial a'a flows, which are distinguished from pahoehoe flows by their higher viscosities and effusion rates. Near the center of the image there is an east-west trending, smooth-floored depression. The somewhat continuous width of this depression suggests that it is not simply formed by the edges of two higher-standing flows on either side, rather it may be a leveed channel created by more fluid lava flows. Faint east-west trending linear to arcuate features in the lower third of the image separate rougher and smoother surfaces, and may be fractures that guided or were barriers to later flows. |
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Lava Flows in Eastern Tharsi
…
PIA03819
Sol (our sun)
Thermal Emission Imaging Sys
…
| Title |
Lava Flows in Eastern Tharsis |
| Original Caption Released with Image |
(Released 31 May 2002) This image may at first appear somewhat bland -- there is little contrast in the surface materials due to dust cover, and there are few impact craters -- but there are some very interesting geologic features here. The great Tharsis volcanoes have produced vast fields of lava flows, such as those shown in this image, to the east of Tharsis Tholus. The flows in this image have moved from west to east, down the regional topographic slope. The lobate edges of the flows are distinctive, and permit the discrimination of many overlapping individual flows that may represent tens, hundreds, thousands, or even millions of years worth of volcanic activity (overlapping relationships are especially evident at the bottom of the image). Viewed at full resolution, the image reveals interesting patterns and textures on the top surfaces of these flows. In particular, at the top of the image, there are numerous parallel curved ridges visible on the upper surfaces of the lava flows. These ridges make the flow surface look somewhat ropy, and at smaller scales this flow might be referred to as pahoehoe, indicative of a relatively fluid type of lava flow. At the scales observed here, however, these features are probably better referred to as pressure ridges. Pressure ridges form on the surface of a lava flow when the upper part of the flow is exposed to air, freezing it, but the insulated unfrozen interior of the flow continues to move down slope (and more material is pushed forward from behind), causing the surface to compress and pile up like a rug. Rough-looking flows with less distinct (more random) patterns on their surfaces may be flows that are more like terrestrial a'a flows, which are distinguished from pahoehoe flows by their higher viscosities and effusion rates. Near the center of the image there is an east-west trending, smooth-floored depression. The somewhat continuous width of this depression suggests that it is not simply formed by the edges of two higher-standing flows on either side, rather it may be a leveed channel created by more fluid lava flows. Faint east-west trending linear to arcuate features in the lower third of the image separate rougher and smoother surfaces, and may be fractures that guided or were barriers to later flows. |
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Noctis Labyrinthus/Valles Ma
…
PIA03813
Sol (our sun)
Thermal Emission Imaging Sys
…
| Title |
Noctis Labyrinthus/Valles Marineris transition |
| Original Caption Released with Image |
(Released 27 May 2002) The Science The transition zone between maze-like troughs of Noctis Labyrinthus and the main Valles Marineris canyon system are shown in this THEMIS visible camera image. This huge system of troughs near the equator of Mars was most likely created by tectonic forces which pulled apart the crust. In the top third of the image, on the western side of the northernmost trough, a buildup of relatively bright material on the plateau has led to an overflow into the trough. Most of the bottom of this trough is covered by sediment deposited from the plateau above. On the right-hand side of this same trough, on the southern wall, there is a thin streak of darker material that also seems to originate from the plateau above. This is most likely a gully formation. This feature could also be a dust avalanche, but because no other similar features are seen, this is unlikely. Other dark material deposited by some unknown process can also be seen all around the easternmost ridge in the trough. Near the bottom of the canyon, layers from the center ridges and the canyon wall can be matched, indicating that the ridges are made of the same material as the wall. Near the bottom of the image, there is yet another depression. This trough is filled with sediment deposited from erosion of the trough wall and possibly from the plateau above. All around the walls of this trough a layer of rocky material can be also be seen. It appears that the areas directly below the rocky ledges are "shielded" from landslide material from above. Finally, in the northwestern wall of this trough, there is an irregular pattern of very bright material not seen anywhere else in the image. Identifying similar formations in other THEMIS visible camera images could provide some context for its occurrence and help us understand how it was formed. The Story Tectonic forces wrenched apart the crust on Mars long ago, forming deep troughs at the Martian equator like the ones seen here. They occur in a transition zone between the maze-like region of Noctis Labyrinthus and the deep canyon system of Valles Marineris, the largest and "grandest" canyon in the solar system. These cracks in the crust can give geologists a good idea of what has happened over the course of the planet's history. Find out a little yourself by taking a closer look at the western side of the trough in the top third of the image. Can you see how the bright sediment from the plateau above has been whisked over the side, overflowing and building up on the floor below? Follow the south wall of this same trough, and you'll come across a dark streak running down (toward the right side of the image). One possibility is that it could be a dust avalanche, but if that were so, you'd think it would have occurred much more often, in more places than just that one spot. Since it didn't, scientists believe it probably isn't a dust avalanche, but could be a gully instead. There's also some more dark material deposited, all around the easternmost ridge in the trough as well. No one is quite sure how it formed there or exactly what it's made of. At the least, what geologists can tell is that the ridges in the trough are made of the same material as the canyon walls, since the layers in each of them match. Finding similarities like these can help piece together the story of Martian geology here. When scientists study THEMIS images, however, they are also on the lookout for anything that looks unusual. Try studying the dark depression that carves out the bottom of this image. It too is filled soft-looking sediments, probably deposited from erosion of the trough wall and possibly from the plateau above. Rocky outcrops all around the walls of this trough shield the areas directly below them from landslides from above. But all that seems pretty regular. Do you see anything that stands out? How about the odd pattern of brighter material that seems almost pasted on the northwestern wall of the trough like dried up glue? This material isn't found elsewhere in this image. Sights like this pose a geological mystery, and one of the only ways to solve it is to seek more clues. Do similar formations occur elsewhere on Mars? Stay tuned with THEMIS researchers, because they'll be looking, trying to understand how and how often such features form. |
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Noctis Labyrinthus/Valles Ma
…
PIA03813
Sol (our sun)
Thermal Emission Imaging Sys
…
| Title |
Noctis Labyrinthus/Valles Marineris transition |
| Original Caption Released with Image |
(Released 27 May 2002) The Science The transition zone between maze-like troughs of Noctis Labyrinthus and the main Valles Marineris canyon system are shown in this THEMIS visible camera image. This huge system of troughs near the equator of Mars was most likely created by tectonic forces which pulled apart the crust. In the top third of the image, on the western side of the northernmost trough, a buildup of relatively bright material on the plateau has led to an overflow into the trough. Most of the bottom of this trough is covered by sediment deposited from the plateau above. On the right-hand side of this same trough, on the southern wall, there is a thin streak of darker material that also seems to originate from the plateau above. This is most likely a gully formation. This feature could also be a dust avalanche, but because no other similar features are seen, this is unlikely. Other dark material deposited by some unknown process can also be seen all around the easternmost ridge in the trough. Near the bottom of the canyon, layers from the center ridges and the canyon wall can be matched, indicating that the ridges are made of the same material as the wall. Near the bottom of the image, there is yet another depression. This trough is filled with sediment deposited from erosion of the trough wall and possibly from the plateau above. All around the walls of this trough a layer of rocky material can be also be seen. It appears that the areas directly below the rocky ledges are "shielded" from landslide material from above. Finally, in the northwestern wall of this trough, there is an irregular pattern of very bright material not seen anywhere else in the image. Identifying similar formations in other THEMIS visible camera images could provide some context for its occurrence and help us understand how it was formed. The Story Tectonic forces wrenched apart the crust on Mars long ago, forming deep troughs at the Martian equator like the ones seen here. They occur in a transition zone between the maze-like region of Noctis Labyrinthus and the deep canyon system of Valles Marineris, the largest and "grandest" canyon in the solar system. These cracks in the crust can give geologists a good idea of what has happened over the course of the planet's history. Find out a little yourself by taking a closer look at the western side of the trough in the top third of the image. Can you see how the bright sediment from the plateau above has been whisked over the side, overflowing and building up on the floor below? Follow the south wall of this same trough, and you'll come across a dark streak running down (toward the right side of the image). One possibility is that it could be a dust avalanche, but if that were so, you'd think it would have occurred much more often, in more places than just that one spot. Since it didn't, scientists believe it probably isn't a dust avalanche, but could be a gully instead. There's also some more dark material deposited, all around the easternmost ridge in the trough as well. No one is quite sure how it formed there or exactly what it's made of. At the least, what geologists can tell is that the ridges in the trough are made of the same material as the canyon walls, since the layers in each of them match. Finding similarities like these can help piece together the story of Martian geology here. When scientists study THEMIS images, however, they are also on the lookout for anything that looks unusual. Try studying the dark depression that carves out the bottom of this image. It too is filled soft-looking sediments, probably deposited from erosion of the trough wall and possibly from the plateau above. Rocky outcrops all around the walls of this trough shield the areas directly below them from landslides from above. But all that seems pretty regular. Do you see anything that stands out? How about the odd pattern of brighter material that seems almost pasted on the northwestern wall of the trough like dried up glue? This material isn't found elsewhere in this image. Sights like this pose a geological mystery, and one of the only ways to solve it is to seek more clues. Do similar formations occur elsewhere on Mars? Stay tuned with THEMIS researchers, because they'll be looking, trying to understand how and how often such features form. |
|
Hesperia Planum
PIA03797
Sol (our sun)
Thermal Emission Imaging Sys
…
| Title |
Hesperia Planum |
| Original Caption Released with Image |
(Released 16 May 2002) The Science This THEMIS visible image shows a close-up view of the ridged plains in Hesperia Planum. This region is the classic locality for martian surfaces that formed in the "middle ages" of martian history. The absolute age of these surfaces is not well known. However, using the abundance of impact craters, it is possible to determine that the Hesperian plains are younger than the ancient cratered terrains that dominate the southern hemisphere, and are older than low-lying plains of the northern hemisphere. In this image it is possible to see that this surface has a large number of 1-3 km diameter craters, indicating that this region is indeed very old and has subjected to a long period of bombardment. A large (80 km diameter) crater occurs just to the north (above) this image. The material that was thrown out onto the surface when the crater was formed ("crater ejecta") can be seen at the top of the THEMIS image. This ejecta material has been heavily eroded and modified since its formation, but there are hints of lobate flow features within the ejecta. Lobate ejecta deposits are thought to indicate that ice was present beneath the surface when the crater was formed, leading to these unusual lobate features. Many of the Hesperian plains are characterized by ridged surfaces. These ridges can be easily seen in the MOLA context image, and several can be seen cutting across the lower portion of the THEMIS image. These "wrinkle" ridges are thought to be the result of compression (squeezing) of the lavas that form these plains. The Story The rough-and-tumble terrain at the top of this image is made of material that was thrown out onto the surface when the massive, almost 50-mile-wide crater in the context image (see right) was blasted out of the surface. This ejected material shows longtime signs of erosion, but what's intriguing to geologists are residual signs of a curved, rounded flow pattern. Seeming to drip down the surface like a very thick, layered candle wax, the appearance of these lobes might mean that ice was present beneath the surface when the crater was formed. If dry dirt and rock alone had been ejected, we probably wouldn't see these flow-like features. Note how tiny craters polka-dot the surface below this ejecta blanket. Most of them have very ragged, eroded edges. This terrain is clearly very old, and has been subjected to a whole lot of bombardment in its time. How old is it? Well, to understand, you need to know a little about the way planets form and evolve. After a new star is formed, there's a lot of leftover dust and gas around it. Eventually, all of this material runs into each other and clumps together due to gravitational attraction. Eventually, these clumps of material grow so large that they become young planets. In a young solar system, there are many pieces of "stuff" still orbiting out there in space, and when they run into a rocky planet, they blast away at the surface, forming craters., Eventually, these leftover orbiting bodies have mostly all impacted. It's a good thing we're in an age where there's relatively little material left to run into our planet, though of course it still happens sometimes. By looking at this surface in the Hesperian plains of Mars, we can see that it's old, but maybe not so ancient as the heavily cratered terrain dominating the southern hemisphere of Mars. . . and yet not so young as the low-lying plains in the northern hemisphere, which were smoothed over at some point late enough in Martian history to be almost crater-free thereafter. That puts the terrain in this image in the so-called "middle ages" of Martian history. By comparing all of the differently aged surfaces they can observe, geologists can piece together a record of Mars' geologic history. Geologists can also make another comparison to understand how planets commonly form and evolve. You can see some ridges that cut across the bottom of the image (seen more clearly in the context image to the right). These "wrinkle" ridges are probably created when the lava that formed these plains was squeezed and compressed. Wrinkle ridges are found not only on Mars, but also on the moon, so that tells us it is not a unique process occurring in only one place in the solar system. |
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Hesperia Planum
PIA03797
Sol (our sun)
Thermal Emission Imaging Sys
…
| Title |
Hesperia Planum |
| Original Caption Released with Image |
(Released 16 May 2002) The Science This THEMIS visible image shows a close-up view of the ridged plains in Hesperia Planum. This region is the classic locality for martian surfaces that formed in the "middle ages" of martian history. The absolute age of these surfaces is not well known. However, using the abundance of impact craters, it is possible to determine that the Hesperian plains are younger than the ancient cratered terrains that dominate the southern hemisphere, and are older than low-lying plains of the northern hemisphere. In this image it is possible to see that this surface has a large number of 1-3 km diameter craters, indicating that this region is indeed very old and has subjected to a long period of bombardment. A large (80 km diameter) crater occurs just to the north (above) this image. The material that was thrown out onto the surface when the crater was formed ("crater ejecta") can be seen at the top of the THEMIS image. This ejecta material has been heavily eroded and modified since its formation, but there are hints of lobate flow features within the ejecta. Lobate ejecta deposits are thought to indicate that ice was present beneath the surface when the crater was formed, leading to these unusual lobate features. Many of the Hesperian plains are characterized by ridged surfaces. These ridges can be easily seen in the MOLA context image, and several can be seen cutting across the lower portion of the THEMIS image. These "wrinkle" ridges are thought to be the result of compression (squeezing) of the lavas that form these plains. The Story The rough-and-tumble terrain at the top of this image is made of material that was thrown out onto the surface when the massive, almost 50-mile-wide crater in the context image (see right) was blasted out of the surface. This ejected material shows longtime signs of erosion, but what's intriguing to geologists are residual signs of a curved, rounded flow pattern. Seeming to drip down the surface like a very thick, layered candle wax, the appearance of these lobes might mean that ice was present beneath the surface when the crater was formed. If dry dirt and rock alone had been ejected, we probably wouldn't see these flow-like features. Note how tiny craters polka-dot the surface below this ejecta blanket. Most of them have very ragged, eroded edges. This terrain is clearly very old, and has been subjected to a whole lot of bombardment in its time. How old is it? Well, to understand, you need to know a little about the way planets form and evolve. After a new star is formed, there's a lot of leftover dust and gas around it. Eventually, all of this material runs into each other and clumps together due to gravitational attraction. Eventually, these clumps of material grow so large that they become young planets. In a young solar system, there are many pieces of "stuff" still orbiting out there in space, and when they run into a rocky planet, they blast away at the surface, forming craters., Eventually, these leftover orbiting bodies have mostly all impacted. It's a good thing we're in an age where there's relatively little material left to run into our planet, though of course it still happens sometimes. By looking at this surface in the Hesperian plains of Mars, we can see that it's old, but maybe not so ancient as the heavily cratered terrain dominating the southern hemisphere of Mars. . . and yet not so young as the low-lying plains in the northern hemisphere, which were smoothed over at some point late enough in Martian history to be almost crater-free thereafter. That puts the terrain in this image in the so-called "middle ages" of Martian history. By comparing all of the differently aged surfaces they can observe, geologists can piece together a record of Mars' geologic history. Geologists can also make another comparison to understand how planets commonly form and evolve. You can see some ridges that cut across the bottom of the image (seen more clearly in the context image to the right). These "wrinkle" ridges are probably created when the lava that formed these plains was squeezed and compressed. Wrinkle ridges are found not only on Mars, but also on the moon, so that tells us it is not a unique process occurring in only one place in the solar system. |
|
Utopia Planitia
PIA03796
Sol (our sun)
Thermal Emission Imaging Sys
…
| Title |
Utopia Planitia |
| Original Caption Released with Image |
(Released 15 May 2002) The Science This image is located in Utopia Planitia, a large plain in the northern hemisphere. It is believed that this basin is the result of a large impact. On the right side of the image is a partially imaged crater with a well-preserved ejecta blanket. The morphology of the ejecta implies that the crater is young relative to the surrounding material and has not undergone extensive deposition or erosion. Surrounding the crater are polygonal troughs in the smooth surface material. This polygon pattern is relatively common in the northern plains of Mars, and are primarily located in Acidalia Planitia, Elysium Planitia, and Utopia Planitia. These troughs are believed to be small grabbens, however, scientist are currently debating the origin of these features. The two most accepted hypotheses are that these grabbens either form as volcanic material cools and contracts, or are produced as sediment shrinks as a result of compaction. The Story When you think of Utopia, you probably don't think of a large Martian plain, riddled with troughs and pockmarked by craters. Of course, it may actually be a more fitting name than you think. When Sir Thomas More wrote his book about a fictitiously optimal place guided and governed by reason, he made up the word utopia from Greek words meaning "nowhere." Utopia Planitia became "somewhere" for the first time, however, when its first visitor, the Viking 2 lander, settled down and analyzed the area. And scientists today are using their own reasoning and logic to discern even more about how this northern Martian plain developed geologically. Right now, scientists have two hypotheses for how the troughs seen here were formed. Because Utopia Planitia is a volcanic region of Mars, these rifts in the surface could have formed when volcanic material cooled and then contracted. Alternatively, this area might be made up of a lot of sediments - small particles of rock, soil, and dust deposited in the area. Just like any loose material, it could have compacted together in places or "shrunk down" to create the lowered rifts in the terrain. The polygonal patterns of these troughs can be seen more widely in the context image to the right. On Earth, we can sometimes see this pattern occurring in the Arctic and subarctic, where permafrost creates polygonal, "frozen-soil wedges" that form an almost honeycomb pattern throughout the terrain. We know from Viking 2 pictures that it can be pretty cold in this area, as a thin layer of white ground frost was observed there during a few of the Martian winters. The whiter, brighter material near the crater, however, isn't frost or snow, but instead the record of all of the material that was once ejected from the crater at the left-hand-side of the image. You can see by the smoothness of the crater rim and the clarity of where the ejected material landed that there hasn't been much erosion. That means this crater is fairly young. |
|
Utopia Planitia
PIA03796
Sol (our sun)
Thermal Emission Imaging Sys
…
| Title |
Utopia Planitia |
| Original Caption Released with Image |
(Released 15 May 2002) The Science This image is located in Utopia Planitia, a large plain in the northern hemisphere. It is believed that this basin is the result of a large impact. On the right side of the image is a partially imaged crater with a well-preserved ejecta blanket. The morphology of the ejecta implies that the crater is young relative to the surrounding material and has not undergone extensive deposition or erosion. Surrounding the crater are polygonal troughs in the smooth surface material. This polygon pattern is relatively common in the northern plains of Mars, and are primarily located in Acidalia Planitia, Elysium Planitia, and Utopia Planitia. These troughs are believed to be small grabbens, however, scientist are currently debating the origin of these features. The two most accepted hypotheses are that these grabbens either form as volcanic material cools and contracts, or are produced as sediment shrinks as a result of compaction. The Story When you think of Utopia, you probably don't think of a large Martian plain, riddled with troughs and pockmarked by craters. Of course, it may actually be a more fitting name than you think. When Sir Thomas More wrote his book about a fictitiously optimal place guided and governed by reason, he made up the word utopia from Greek words meaning "nowhere." Utopia Planitia became "somewhere" for the first time, however, when its first visitor, the Viking 2 lander, settled down and analyzed the area. And scientists today are using their own reasoning and logic to discern even more about how this northern Martian plain developed geologically. Right now, scientists have two hypotheses for how the troughs seen here were formed. Because Utopia Planitia is a volcanic region of Mars, these rifts in the surface could have formed when volcanic material cooled and then contracted. Alternatively, this area might be made up of a lot of sediments - small particles of rock, soil, and dust deposited in the area. Just like any loose material, it could have compacted together in places or "shrunk down" to create the lowered rifts in the terrain. The polygonal patterns of these troughs can be seen more widely in the context image to the right. On Earth, we can sometimes see this pattern occurring in the Arctic and subarctic, where permafrost creates polygonal, "frozen-soil wedges" that form an almost honeycomb pattern throughout the terrain. We know from Viking 2 pictures that it can be pretty cold in this area, as a thin layer of white ground frost was observed there during a few of the Martian winters. The whiter, brighter material near the crater, however, isn't frost or snow, but instead the record of all of the material that was once ejected from the crater at the left-hand-side of the image. You can see by the smoothness of the crater rim and the clarity of where the ejected material landed that there hasn't been much erosion. That means this crater is fairly young. |
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Mars Surface Layers in Infra
…
PIA03817
Sol (our sun)
Thermal Emission Imaging Sys
…
| Title |
Mars Surface Layers in Infrared |
| Original Caption Released with Image |
(Released 29 May 2002) Infrared imaging from NASA's Mars Odyssey spacecraft shows signs of layering exposed at the surface in a region of Mars called Terra Meridiani. The brightness levels show daytime surface temperatures, which range from about minus 20 degrees to zero degrees Celsius (minus 4 degrees to 32 degrees Fahrenheit). Many of the temperature variations are due to slope effects, with sun-facing slopes warmer than shaded slopes. However, several rock layers can be seen to have distinctly different temperatures, indicating that physical properties vary from layer to layer. These differences suggest that the environment on this part of Mars varied through time as these layers were formed. The image is a mosaic combining four exposures taken by the thermal emission imaging system aboard Odyssey during the first two months of the Odyssey mapping mission, which began in February 2002. The area shown is about 120 kilometers (75 miles) across, at approximately 358 degrees east (2 degrees west) longitude and 3 degrees north latitude. |
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Mars Surface Layers in Infra
…
PIA03817
Sol (our sun)
Thermal Emission Imaging Sys
…
| Title |
Mars Surface Layers in Infrared |
| Original Caption Released with Image |
(Released 29 May 2002) Infrared imaging from NASA's Mars Odyssey spacecraft shows signs of layering exposed at the surface in a region of Mars called Terra Meridiani. The brightness levels show daytime surface temperatures, which range from about minus 20 degrees to zero degrees Celsius (minus 4 degrees to 32 degrees Fahrenheit). Many of the temperature variations are due to slope effects, with sun-facing slopes warmer than shaded slopes. However, several rock layers can be seen to have distinctly different temperatures, indicating that physical properties vary from layer to layer. These differences suggest that the environment on this part of Mars varied through time as these layers were formed. The image is a mosaic combining four exposures taken by the thermal emission imaging system aboard Odyssey during the first two months of the Odyssey mapping mission, which began in February 2002. The area shown is about 120 kilometers (75 miles) across, at approximately 358 degrees east (2 degrees west) longitude and 3 degrees north latitude. |
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Northwestern Branch of Manga
…
PIA03827
Sol (our sun)
Thermal Emission Imaging Sys
…
| Title |
Northwestern Branch of Mangala Vallis |
| Original Caption Released with Image |
(Released 12 June 2002) The Science One of the many branches of the Mangala Vallis channel system is seen in this image. The water that likely carved the channels emerged from a huge graben or fracture almost 1000 km to the south. The THEMIS image shows where one of the channels exits the cratered highlands terrain onto the lowland plains. A bright scarp marks the transition between the two terrain types and demonstrates that in this location the highlands terrain is being eroded back. Note how the floor of the main channel appears to be at the same level as the lowland terrain, suggestive of a base level where erosion is no longer effective. Most of the steep slope faces in the image display darker slope streaks that are thought to be dust avalanche scars and indicate that a relatively thick mantle of dust is present in this region. Wind-sculpted ridges known as yardangs cover many of the surfaces throughout the area as shown by images from the Mars Global Surveyor mission. Most of them are at the limit of resolution in the THEMIS image but some are evident on the floor of the main channel at the point at which a smaller side channel enters. In this location they appear to extend right up to the base of the channel wall, giving the appearance that they are emerging from underneath the thick pile of material into which the channel is eroded. This suggests a geologic history in which a preexisting landscape of eroded yardangs was covered over by a thick pile of younger material that is now eroding back down to the original level. Alternatively, it is possible that the yardangs formed more recently at the abrupt transition between the channel floor and wall. More analysis is necessary to sort out the story. The Story This channel system is named "Mangala," the word for Mars in Sanskrit, a language of the Hindus of India that goes back more than 4,000 years, with written literature almost as long. Great epic tales have been written in this language, and Odyssey is continuing in the spirit of those adventures with its daily discoveries. Long ago, many thousands of years before Sanskrit was spoken on the Earth, a rush of water emerged from a giant fracture in the Martian land, carving the channels seen above. Since this fracture is located almost 600 miles to the south of this picture, you can only image the force of the flood. Today, the only real movement is the tired fall of dust avalanches down the channel slopes, which leave long dark trickles down the side. It's a dry, dusty world now, with a thick layer of dust everywhere. This image was taken at a place of transformation on Mars, where the cratered highlands meet the smooth, lowland plains. You can see that especially well in the context image to the right. Erosion is working tirelessly over time to bring the highlands level with the lowland terrain, but that will take eons more time into the future. Erosion may be "deadly" to geological features, but it doesn't always happen quickly. If, you want to look at one thing close up in this image, click on the above image and check out the floor of the main channel, just at the point where a smaller side channel enters (about a third of the way up). What you'll find are wind-sculpted ridges known as yardangs (some of them are almost triangular). What's interesting about these ridges is that they seem to have eroded long ago, then were covered by a thick pile of younger material, which is now itself eroding back, uncovering them once again. Yardangs are pretty common in this region of Mars, but if you have trouble finding them in many THEMIS images, don't worry, you're not alone. That's because the THEMIS camera is designed to take pictures of a larger area than its sister camera on the Mars Global Surveyor spacecraft, so some smaller yardangs are barely detectable. The Mars Orbital Camera, however, takes more detailed pictures of a narrower slice of the Martian landscape, and has shown many yardangs in the area. The great thing is that the THEMIS and MOC cameras are very complementary to one another. It's important to get the larger context of the terrain, as well as the sharp details of a tinier area for the greatest understanding possible. For example, while the yardangs in this image seem to be emerging from a blanket of younger material, it's also possible that they formed more recently at the abrupt transition between the channel floor and the wall. More analysis - and more pictures from both cameras! - will be needed to sort out the story. |
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Northwestern Branch of Manga
…
PIA03827
Sol (our sun)
Thermal Emission Imaging Sys
…
| Title |
Northwestern Branch of Mangala Vallis |
| Original Caption Released with Image |
(Released 12 June 2002) The Science One of the many branches of the Mangala Vallis channel system is seen in this image. The water that likely carved the channels emerged from a huge graben or fracture almost 1000 km to the south. The THEMIS image shows where one of the channels exits the cratered highlands terrain onto the lowland plains. A bright scarp marks the transition between the two terrain types and demonstrates that in this location the highlands terrain is being eroded back. Note how the floor of the main channel appears to be at the same level as the lowland terrain, suggestive of a base level where erosion is no longer effective. Most of the steep slope faces in the image display darker slope streaks that are thought to be dust avalanche scars and indicate that a relatively thick mantle of dust is present in this region. Wind-sculpted ridges known as yardangs cover many of the surfaces throughout the area as shown by images from the Mars Global Surveyor mission. Most of them are at the limit of resolution in the THEMIS image but some are evident on the floor of the main channel at the point at which a smaller side channel enters. In this location they appear to extend right up to the base of the channel wall, giving the appearance that they are emerging from underneath the thick pile of material into which the channel is eroded. This suggests a geologic history in which a preexisting landscape of eroded yardangs was covered over by a thick pile of younger material that is now eroding back down to the original level. Alternatively, it is possible that the yardangs formed more recently at the abrupt transition between the channel floor and wall. More analysis is necessary to sort out the story. The Story This channel system is named "Mangala," the word for Mars in Sanskrit, a language of the Hindus of India that goes back more than 4,000 years, with written literature almost as long. Great epic tales have been written in this language, and Odyssey is continuing in the spirit of those adventures with its daily discoveries. Long ago, many thousands of years before Sanskrit was spoken on the Earth, a rush of water emerged from a giant fracture in the Martian land, carving the channels seen above. Since this fracture is located almost 600 miles to the south of this picture, you can only image the force of the flood. Today, the only real movement is the tired fall of dust avalanches down the channel slopes, which leave long dark trickles down the side. It's a dry, dusty world now, with a thick layer of dust everywhere. This image was taken at a place of transformation on Mars, where the cratered highlands meet the smooth, lowland plains. You can see that especially well in the context image to the right. Erosion is working tirelessly over time to bring the highlands level with the lowland terrain, but that will take eons more time into the future. Erosion may be "deadly" to geological features, but it doesn't always happen quickly. If, you want to look at one thing close up in this image, click on the above image and check out the floor of the main channel, just at the point where a smaller side channel enters (about a third of the way up). What you'll find are wind-sculpted ridges known as yardangs (some of them are almost triangular). What's interesting about these ridges is that they seem to have eroded long ago, then were covered by a thick pile of younger material, which is now itself eroding back, uncovering them once again. Yardangs are pretty common in this region of Mars, but if you have trouble finding them in many THEMIS images, don't worry, you're not alone. That's because the THEMIS camera is designed to take pictures of a larger area than its sister camera on the Mars Global Surveyor spacecraft, so some smaller yardangs are barely detectable. The Mars Orbital Camera, however, takes more detailed pictures of a narrower slice of the Martian landscape, and has shown many yardangs in the area. The great thing is that the THEMIS and MOC cameras are very complementary to one another. It's important to get the larger context of the terrain, as well as the sharp details of a tinier area for the greatest understanding possible. For example, while the yardangs in this image seem to be emerging from a blanket of younger material, it's also possible that they formed more recently at the abrupt transition between the channel floor and the wall. More analysis - and more pictures from both cameras! - will be needed to sort out the story. |
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Water Ice Clouds over the No
…
PIA03795
Sol (our sun)
Thermal Emission Imaging Sys
…
| Title |
Water Ice Clouds over the Northern Plains |
| Original Caption Released with Image |
(Released 14 May 2002) The Science This image, centered near 48.5 N and 240.5 W, displays splotchy water ice clouds that obscure the northern lowland plains in the region where the Viking 2 spacecraft landed. This image is far enough north to catch the edge of the north polar hood that develops during the northern winter. This is a cap of water and carbon dioxide ice clouds that form over the Martian north pole. As Mars progresses into northern spring, the persistent north polar hood ice clouds will dissipate and the surface viewing conditions will improve greatly. As the season develops, an equatorial belt of water ice clouds will form. This belt of water ice clouds is as characteristic of the Martian climate as the southern hemisphere summer dust storm season. Seasons on Mars have a dramatic effect on the state of the dynamic Martian atmosphere. The Story Muted in an almost air-brushed manner, this image doesn't have the crispness that most THEMIS images have. That's because clouds were rising over the surface of the red planet on the day this picture was taken. Finding clouds on Mars might remind us of conditions here on Earth, but these Martian clouds are made of frozen water and frozen carbon dioxide -- in other words, clouds of ice and "dry ice." Strange as that may sound, the clouds seen here form on a pretty regular basis at the north Martian pole during its winter season. As springtime comes to the northern hemisphere of Mars (and fall comes to the southern), these clouds will slowly disappear, and a nice belt of water ice clouds will form around the equator. So, if you were a THEMIS camera aimer, that might tell you when your best viewing conditions for different areas on Mars would be. As interesting as clear pictures of Martian landforms are, however, you wouldn't want to bypass the weather altogether. Pictures showing seasonal shifts are great for scientists to study, because they reveal a lot about the patterns of the Martian climate and the circulation of the atmosphere. There are a lot of interesting global climate relationships to study. For example, when it's winter in the north of Mars and clouds like the ones in this image form, dust storms rage in the south of Mars, where it's summer. So why does Mars have these wild seasons? Like the Earth, Mars is tilted on its axis. As it travels in its orbit around the sun, the angle between the Earth's axis and the Earth-Sun line changes. That's true for Mars as well. As each point on Mars spins on the rotating red planet each day, the part of the cycle spent in sunlight (day) and shadow (night) just aren't equal because of these angles. When day is longer than night (summer) in the north, night is longer than day (winter) in the south. Half a year later, when Mars has traveled in its orbit to the other side of the sun, the situation is exactly reversed. All this sounds familiar to Earthlings, but there's yet one more difference. Mars is farther away from the sun than the Earth., That means it takes longer for Mars to make a trip around the sun in its orbit than the Earth does -- about twice as long, in fact. That means that the seasons on Mars also last twice as long! |
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Water Ice Clouds over the No
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PIA03795
Sol (our sun)
Thermal Emission Imaging Sys
…
| Title |
Water Ice Clouds over the Northern Plains |
| Original Caption Released with Image |
(Released 14 May 2002) The Science This image, centered near 48.5 N and 240.5 W, displays splotchy water ice clouds that obscure the northern lowland plains in the region where the Viking 2 spacecraft landed. This image is far enough north to catch the edge of the north polar hood that develops during the northern winter. This is a cap of water and carbon dioxide ice clouds that form over the Martian north pole. As Mars progresses into northern spring, the persistent north polar hood ice clouds will dissipate and the surface viewing conditions will improve greatly. As the season develops, an equatorial belt of water ice clouds will form. This belt of water ice clouds is as characteristic of the Martian climate as the southern hemisphere summer dust storm season. Seasons on Mars have a dramatic effect on the state of the dynamic Martian atmosphere. The Story Muted in an almost air-brushed manner, this image doesn't have the crispness that most THEMIS images have. That's because clouds were rising over the surface of the red planet on the day this picture was taken. Finding clouds on Mars might remind us of conditions here on Earth, but these Martian clouds are made of frozen water and frozen carbon dioxide -- in other words, clouds of ice and "dry ice." Strange as that may sound, the clouds seen here form on a pretty regular basis at the north Martian pole during its winter season. As springtime comes to the northern hemisphere of Mars (and fall comes to the southern), these clouds will slowly disappear, and a nice belt of water ice clouds will form around the equator. So, if you were a THEMIS camera aimer, that might tell you when your best viewing conditions for different areas on Mars would be. As interesting as clear pictures of Martian landforms are, however, you wouldn't want to bypass the weather altogether. Pictures showing seasonal shifts are great for scientists to study, because they reveal a lot about the patterns of the Martian climate and the circulation of the atmosphere. There are a lot of interesting global climate relationships to study. For example, when it's winter in the north of Mars and clouds like the ones in this image form, dust storms rage in the south of Mars, where it's summer. So why does Mars have these wild seasons? Like the Earth, Mars is tilted on its axis. As it travels in its orbit around the sun, the angle between the Earth's axis and the Earth-Sun line changes. That's true for Mars as well. As each point on Mars spins on the rotating red planet each day, the part of the cycle spent in sunlight (day) and shadow (night) just aren't equal because of these angles. When day is longer than night (summer) in the north, night is longer than day (winter) in the south. Half a year later, when Mars has traveled in its orbit to the other side of the sun, the situation is exactly reversed. All this sounds familiar to Earthlings, but there's yet one more difference. Mars is farther away from the sun than the Earth., That means it takes longer for Mars to make a trip around the sun in its orbit than the Earth does -- about twice as long, in fact. That means that the seasons on Mars also last twice as long! |
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Becquerel Crater Deposit
PIA03814
Sol (our sun)
Thermal Emission Imaging Sys
…
| Title |
Becquerel Crater Deposit |
| Original Caption Released with Image |
(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. |
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