Fresh washes on Mars?
Click for full image.
Cool image time! The photo to the right, cropped and reduced to post here, was taken on January 29, 2021 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows what the science team labels as “Fresh Shallow Valleys”. The section I have focused on shows a particularly interesting meander next to a small crater. The full image shows additional similar channels to the north, with one draining into a larger 3.7 mile wide crater.
The location is in the southern cratered highlands, at about 41 degrees south latitude, where much evidence of buried glacial features are found. That certainly is what we appear to see here. In fact, the wider view afforded by MRO’s context camera reveals many more such channels. That wider view also shows a much larger 18-mile-wide crater just to the north that appears filled with buried ice.
That the scientists label these fresh suggests they think they are relatively young, probably dating from when the most recent cycle of glacial growth probably ended. This would make them about 6 million years ago, based on this paper [pdf] and the second figure from that paper below.
According this graph, it appears Mars’ rotational tilt shifted from about 40 degrees to its present 25 degrees today about six million years ago. When it was 40 degrees the mid-latitudes would have been colder than the poles, and thus water would sublimate from the polar icecaps to fall as snow in the mid-latitudes. Glaciers would form there and grow, flowing down to carve channels such as these.
Since then those glaciers have been inactive. Scientists think (though this remains uncertain) that the poles and mid-latitude glaciers are presently in a steady-state, with neither growing nor shrinking.
Thus, any glaciers in these channels are likely stable at this time. No additional snow is falling on their upstream ends to the west, so they are under no pressure to flow eastward downhill.
Readers!
Please consider supporting my work here at Behind the Black. Your support allows me the freedom and ability to analyze objectively the ongoing renaissance in space, as well as the cultural changes -- for good or ill -- that are happening across America. Fourteen years ago I wrote that SLS and Orion were a bad ideas, a waste of money, would be years behind schedule, and better replaced by commercial private enterprise. Only now does it appear that Washington might finally recognize this reality.
In 2020 when the world panicked over COVID I wrote that the panic was unnecessary, that the virus was apparently simply a variation of the flu, that masks were not simply pointless but if worn incorrectly were a health threat, that the lockdowns were a disaster and did nothing to stop the spread of COVID. Only in the past year have some of our so-called experts in the health field have begun to recognize these facts.
Your help allows me to do this kind of intelligent analysis. I take no advertising or sponsors, so my reporting isn't influenced by donations by established space or drug companies. Instead, I rely entirely on donations and subscriptions from my readers, which gives me the freedom to write what I think, unencumbered by outside influences.
You can support me either by giving a one-time contribution or a regular subscription. There are four ways of doing so:
1. Zelle: This is the only internet method that charges no fees. All you have to do is use the Zelle link at your internet bank and give my name and email address (zimmerman at nasw dot org). What you donate is what I get.
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Click for full image.
Cool image time! The photo to the right, cropped and reduced to post here, was taken on January 29, 2021 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows what the science team labels as “Fresh Shallow Valleys”. The section I have focused on shows a particularly interesting meander next to a small crater. The full image shows additional similar channels to the north, with one draining into a larger 3.7 mile wide crater.
The location is in the southern cratered highlands, at about 41 degrees south latitude, where much evidence of buried glacial features are found. That certainly is what we appear to see here. In fact, the wider view afforded by MRO’s context camera reveals many more such channels. That wider view also shows a much larger 18-mile-wide crater just to the north that appears filled with buried ice.
That the scientists label these fresh suggests they think they are relatively young, probably dating from when the most recent cycle of glacial growth probably ended. This would make them about 6 million years ago, based on this paper [pdf] and the second figure from that paper below.
According this graph, it appears Mars’ rotational tilt shifted from about 40 degrees to its present 25 degrees today about six million years ago. When it was 40 degrees the mid-latitudes would have been colder than the poles, and thus water would sublimate from the polar icecaps to fall as snow in the mid-latitudes. Glaciers would form there and grow, flowing down to carve channels such as these.
Since then those glaciers have been inactive. Scientists think (though this remains uncertain) that the poles and mid-latitude glaciers are presently in a steady-state, with neither growing nor shrinking.
Thus, any glaciers in these channels are likely stable at this time. No additional snow is falling on their upstream ends to the west, so they are under no pressure to flow eastward downhill.
Readers!
Please consider supporting my work here at Behind the Black. Your support allows me the freedom and ability to analyze objectively the ongoing renaissance in space, as well as the cultural changes -- for good or ill -- that are happening across America. Fourteen years ago I wrote that SLS and Orion were a bad ideas, a waste of money, would be years behind schedule, and better replaced by commercial private enterprise. Only now does it appear that Washington might finally recognize this reality.
In 2020 when the world panicked over COVID I wrote that the panic was unnecessary, that the virus was apparently simply a variation of the flu, that masks were not simply pointless but if worn incorrectly were a health threat, that the lockdowns were a disaster and did nothing to stop the spread of COVID. Only in the past year have some of our so-called experts in the health field have begun to recognize these facts.
Your help allows me to do this kind of intelligent analysis. I take no advertising or sponsors, so my reporting isn't influenced by donations by established space or drug companies. Instead, I rely entirely on donations and subscriptions from my readers, which gives me the freedom to write what I think, unencumbered by outside influences.
You can support me either by giving a one-time contribution or a regular subscription. There are four ways of doing so:
1. Zelle: This is the only internet method that charges no fees. All you have to do is use the Zelle link at your internet bank and give my name and email address (zimmerman at nasw dot org). What you donate is what I get.
2. Patreon: Go to my website there and pick one of five monthly subscription amounts, or by making a one-time donation.
3. A Paypal Donation or subscription:
4. Donate by check, payable to Robert Zimmerman and mailed to
Behind The Black
c/o Robert Zimmerman
P.O.Box 1262
Cortaro, AZ 85652
You can also support me by buying one of my books, as noted in the boxes interspersed throughout the webpage or shown in the menu above.
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