Icy scarps in the high southern latitudes of Mars
Click for full image.
Cool image time! The photo to the right, rotated, cropped, and reduced to post here, was taken on May 30, 2022 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows what the scientists label “Patching Mantling Unit,” located at about 57 degrees south latitude in a region where scientists have found good evidence of near surface ice. The top layer, or mantle, is likely patchy because it has a high content of water ice and is sublimating away. That almost all the cliffs are south-facing, which in the southern hemisphere gets the least direct sunlight, supports this supposition. For example, in the crater at the bottom of the image the ice would have disappeared first from the north-facing interior rim slopes, with the sublimation slowly working its way northward. Thus we have that butte extending out from the north rim.
The global map below not only indicates the location of these scallops with the green dot, it illustrates the overall icy nature of most of the Mars.
The map above, first posted in February 2021 and adapted from figures 4 and 12 of this paper, shows the areas on Mars where the evidence suggests ample and easily accessible ice, underground but close to the surface.
The red dots and diamonds indicate recent impact craters that temporarily exposed the underground ice layer that would normally not be visible. The white dots and diamonds indicate ice scarps with visible ice layers in their cliff faces. The size of these locations is greatly exaggerated.
The two hatched lines at 30 degrees latitude, north and south, indicate the closest to the equator that scientists have detected evidence of glacial ice.
I want my readers to always think of this map when they read media reports about the lack of water on Mars. Such reports are incorrect. Except for its equatorial regions, Mars has a lot of water, much of it very near the surface, but it is frozen, making this planet more like Antarctica then the Sahara.
On Christmas Eve 1968 three Americans became the first humans to visit another world. What they did to celebrate was unexpected and profound, and will be remembered throughout all human history. Genesis: the Story of Apollo 8, Robert Zimmerman's classic history of humanity's first journey to another world, tells that story, and it is now available as both an ebook and an audiobook, both with a foreword by Valerie Anders and a new introduction by Robert Zimmerman.
The print edition can be purchased at Amazon. from any other book seller, or direct from my ebook publisher, ebookit.
The ebook is available everywhere for $5.99 (before discount) at amazon, or direct from my ebook publisher, ebookit. If you buy it from ebookit you don't support the big tech companies and the author gets a bigger cut much sooner.
The audiobook is also available at all these vendors, and is also free with a 30-day trial membership to Audible.
"Not simply about one mission, [Genesis] is also the history of America's quest for the moon... Zimmerman has done a masterful job of tying disparate events together into a solid account of one of America's greatest human triumphs."--San Antonio Express-News
Click for full image.
Cool image time! The photo to the right, rotated, cropped, and reduced to post here, was taken on May 30, 2022 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows what the scientists label “Patching Mantling Unit,” located at about 57 degrees south latitude in a region where scientists have found good evidence of near surface ice. The top layer, or mantle, is likely patchy because it has a high content of water ice and is sublimating away. That almost all the cliffs are south-facing, which in the southern hemisphere gets the least direct sunlight, supports this supposition. For example, in the crater at the bottom of the image the ice would have disappeared first from the north-facing interior rim slopes, with the sublimation slowly working its way northward. Thus we have that butte extending out from the north rim.
The global map below not only indicates the location of these scallops with the green dot, it illustrates the overall icy nature of most of the Mars.
The map above, first posted in February 2021 and adapted from figures 4 and 12 of this paper, shows the areas on Mars where the evidence suggests ample and easily accessible ice, underground but close to the surface.
The red dots and diamonds indicate recent impact craters that temporarily exposed the underground ice layer that would normally not be visible. The white dots and diamonds indicate ice scarps with visible ice layers in their cliff faces. The size of these locations is greatly exaggerated.
The two hatched lines at 30 degrees latitude, north and south, indicate the closest to the equator that scientists have detected evidence of glacial ice.
I want my readers to always think of this map when they read media reports about the lack of water on Mars. Such reports are incorrect. Except for its equatorial regions, Mars has a lot of water, much of it very near the surface, but it is frozen, making this planet more like Antarctica then the Sahara.
On Christmas Eve 1968 three Americans became the first humans to visit another world. What they did to celebrate was unexpected and profound, and will be remembered throughout all human history. Genesis: the Story of Apollo 8, Robert Zimmerman's classic history of humanity's first journey to another world, tells that story, and it is now available as both an ebook and an audiobook, both with a foreword by Valerie Anders and a new introduction by Robert Zimmerman.
The print edition can be purchased at Amazon. from any other book seller, or direct from my ebook publisher, ebookit. The ebook is available everywhere for $5.99 (before discount) at amazon, or direct from my ebook publisher, ebookit. If you buy it from ebookit you don't support the big tech companies and the author gets a bigger cut much sooner.
The audiobook is also available at all these vendors, and is also free with a 30-day trial membership to Audible.
"Not simply about one mission, [Genesis] is also the history of America's quest for the moon... Zimmerman has done a masterful job of tying disparate events together into a solid account of one of America's greatest human triumphs."--San Antonio Express-News
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