Martian crater with mound of ice? mud? hardened sand?
Click for full image.
Cool image time! The photo to the right, cropped to post here, was taken on October 31, 2022 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows a small 4,000-foot-wide crater that is practically filled with a smooth, almost perfectly spherical mound, with the rest of the crater interior filled with sand dunes and what appears to be glacial debris.
Is that mound also glacial debris, covered with a layer of dirt and dust to protect it? If so, one wonders how the ice ended up in this shape. There are other craters with similar mounds in this region, all suggesting glacial debris but with the same question. Craters with lots of near surface ice in this region more often have a squishy blobby look.
Is the mound instead possibly mud, expressing the existence of a mud/ice volcano? If so, it shows no central pit or caldera, which is typical of such things.
Is it hardened sand? Martian dust that gets blown into craters generally gets trapped there, building up over time. If so, however, why does it have a smooth almost perfectly rounded shape? The ripple sand dunes surrounding it are more like what you would expect.
The small craters on the mound also tell us that it is hardened and old, no matter what it is made of.
The dot just north of 30 degrees latitude marks this crater’s location, in the northern lowland plains of Mars. It therefore would not be surprising to find near surface ice here. The closeness to the 30 degree latitude line however also suggests that near surface ice could possibly be reduced.
Thus, the location really does not help us determine the nature of what we are looking at.
I must add that the image’s colors don’t help much either. The greenish areas could either be coarse bedrock, or frost, based on how the scientists interpret these colors [pdf]. The picture was taken in northern winter, so frost is possible, but if so, it is mysteriously located mostly on the warmer south-facing slopes, not the colder north-facing slopes as one would expect. This is why it might be coarse rocks or bedrock instead. This conclusion is strengthened by an image using a different color filter, which shows this greenish material as purplish-blue, which in that filter also suggests coarse rocks or bedrock.
In either case, the colors don’t tell us what the mound is made of, other than it is covered with dust, based on its yellow color.
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.
Cool image time! The photo to the right, cropped to post here, was taken on October 31, 2022 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows a small 4,000-foot-wide crater that is practically filled with a smooth, almost perfectly spherical mound, with the rest of the crater interior filled with sand dunes and what appears to be glacial debris.
Is that mound also glacial debris, covered with a layer of dirt and dust to protect it? If so, one wonders how the ice ended up in this shape. There are other craters with similar mounds in this region, all suggesting glacial debris but with the same question. Craters with lots of near surface ice in this region more often have a squishy blobby look.
Is the mound instead possibly mud, expressing the existence of a mud/ice volcano? If so, it shows no central pit or caldera, which is typical of such things.
Is it hardened sand? Martian dust that gets blown into craters generally gets trapped there, building up over time. If so, however, why does it have a smooth almost perfectly rounded shape? The ripple sand dunes surrounding it are more like what you would expect.
The small craters on the mound also tell us that it is hardened and old, no matter what it is made of.
The dot just north of 30 degrees latitude marks this crater’s location, in the northern lowland plains of Mars. It therefore would not be surprising to find near surface ice here. The closeness to the 30 degree latitude line however also suggests that near surface ice could possibly be reduced.
Thus, the location really does not help us determine the nature of what we are looking at.
I must add that the image’s colors don’t help much either. The greenish areas could either be coarse bedrock, or frost, based on how the scientists interpret these colors [pdf]. The picture was taken in northern winter, so frost is possible, but if so, it is mysteriously located mostly on the warmer south-facing slopes, not the colder north-facing slopes as one would expect. This is why it might be coarse rocks or bedrock instead. This conclusion is strengthened by an image using a different color filter, which shows this greenish material as purplish-blue, which in that filter also suggests coarse rocks or bedrock.
In either case, the colors don’t tell us what the mound is made of, other than it is covered with dust, based on its yellow color.
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
Ah, the eye of Ghroth/Remina