The very icy high northern latitudes of Mars
Click for full image.
Today’s cool image to me illustrates how the presence of near surface ice in the high latitudes of the northern lowland plains of Mars helps to produce a very strange and alien terrain.
The picture to the right, rotated, cropped, reduced, and sharpened to post here, was taken on January 31, 2023 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows a typical example of what the scientists have dubbed a “pedestal crater,” where the crater ends up higher than the surrounding terrain because the impact had packed the ground and made it more resistant to erosion.
This theory however does not explain entirely what we see here. That apron mesa surrounding the crater also resembles the kind of splash field that is created when an impact occurs in less dense ice-rich ground. Note too the soft stippled nature of the ground. Wind erosion is not the sole cause of change here.
The white dot near the top of the overview map to the right marks this crater’s location, at 57 degrees north latitude. At this latitude research has suggested there is a great deal of near surface ice, impregnating all the soil. The picture certainly gives that impression.
For example, the stippled look likely comes when the wind exposes a very small spot of ice, which then sublimates away to leave a tiny hole. Similarly, that sublimation process probably helps explain the creation of pedestal crater, as the ground in the plains is softer and ice-filled, while the crater’s splash field is likely packed dirt with almost no ice, which sublimated away instantly during the impact.
Make sure you look at the full image. This terrain as lots of strange features, all of which I think are caused by its icy nature, the low gravity of Mars, its very cold climate, and its very thin but active atmosphere.
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 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.
Today’s cool image to me illustrates how the presence of near surface ice in the high latitudes of the northern lowland plains of Mars helps to produce a very strange and alien terrain.
The picture to the right, rotated, cropped, reduced, and sharpened to post here, was taken on January 31, 2023 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows a typical example of what the scientists have dubbed a “pedestal crater,” where the crater ends up higher than the surrounding terrain because the impact had packed the ground and made it more resistant to erosion.
This theory however does not explain entirely what we see here. That apron mesa surrounding the crater also resembles the kind of splash field that is created when an impact occurs in less dense ice-rich ground. Note too the soft stippled nature of the ground. Wind erosion is not the sole cause of change here.
The white dot near the top of the overview map to the right marks this crater’s location, at 57 degrees north latitude. At this latitude research has suggested there is a great deal of near surface ice, impregnating all the soil. The picture certainly gives that impression.
For example, the stippled look likely comes when the wind exposes a very small spot of ice, which then sublimates away to leave a tiny hole. Similarly, that sublimation process probably helps explain the creation of pedestal crater, as the ground in the plains is softer and ice-filled, while the crater’s splash field is likely packed dirt with almost no ice, which sublimated away instantly during the impact.
Make sure you look at the full image. This terrain as lots of strange features, all of which I think are caused by its icy nature, the low gravity of Mars, its very cold climate, and its very thin but active atmosphere.
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 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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