The colorful layers of the Martian north pole icecap
Click for full image.
Click for full image.
Today’s cool image above, rotated, reduced, and annotated to post here, comes from today’s picture of the day for the high resolution camera on Mars Reconnaissance Orbiter (MRO), which in turn is a retrospective of a captioned image first taken in 2010. The photo to the right, rotated, cropped, and reduced to post here, shows a larger area to provide some context. For this image north is towards the top. The rectangle indicates the area covered by the picture above.
The ice cap at the north pole is about 600 miles across and a little less than 7,000 feet deep, made up of many layers that are a mixture of water ice and cemented dust and sand. From the picture’s caption:
In many locations erosion has created scarps and troughs that expose this layering. The tan colored layers are the dusty water ice of the polar layered deposits; however a section of bluish layers is visible below them. These bluish layers contain sand-sized rock fragments that likely formed a large polar dunefield before the overlying dusty ice was deposited.
The lack of a polar ice cap in this past epoch attests to the variability of the Martian climate, which undergoes larger changes over time than that of the Earth.
The overview map below provides some further context.
The white cross marks the location of these layers, right on the edge of the cap. While numerous images of the this part of the cap’s edge have in past springs captured many many avalanches, as they happened, this particular hollow has not been such a place. Apparently the slope here is gentle enough that any changes produce by the seasonal freeze-thaw cycle does not lead to as many such events.
The variety of layers not only show a variety of past Martian cyclical changes, they are also likely only hint at the number of layers that exist. I suspect that a rover’s eye view, from only a few feet away, would identify layers within layers within layers, all marking a past cycle or event, some of which might even be as short as a single global dust storm.
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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3. A Paypal Donation or subscription:
4. Donate by check, payable to Robert Zimmerman and mailed to
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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.
Click for full image.
Click for full image.
Today’s cool image above, rotated, reduced, and annotated to post here, comes from today’s picture of the day for the high resolution camera on Mars Reconnaissance Orbiter (MRO), which in turn is a retrospective of a captioned image first taken in 2010. The photo to the right, rotated, cropped, and reduced to post here, shows a larger area to provide some context. For this image north is towards the top. The rectangle indicates the area covered by the picture above.
The ice cap at the north pole is about 600 miles across and a little less than 7,000 feet deep, made up of many layers that are a mixture of water ice and cemented dust and sand. From the picture’s caption:
In many locations erosion has created scarps and troughs that expose this layering. The tan colored layers are the dusty water ice of the polar layered deposits; however a section of bluish layers is visible below them. These bluish layers contain sand-sized rock fragments that likely formed a large polar dunefield before the overlying dusty ice was deposited.
The lack of a polar ice cap in this past epoch attests to the variability of the Martian climate, which undergoes larger changes over time than that of the Earth.
The overview map below provides some further context.
The white cross marks the location of these layers, right on the edge of the cap. While numerous images of the this part of the cap’s edge have in past springs captured many many avalanches, as they happened, this particular hollow has not been such a place. Apparently the slope here is gentle enough that any changes produce by the seasonal freeze-thaw cycle does not lead to as many such events.
The variety of layers not only show a variety of past Martian cyclical changes, they are also likely only hint at the number of layers that exist. I suspect that a rover’s eye view, from only a few feet away, would identify layers within layers within layers, all marking a past cycle or event, some of which might even be as short as a single global dust storm.
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.
So would coring this cap be the thing to do to find some data on the history of the planet?
I wonder if there are characteristic layers of dust and ejecta that represent Mars history.
Could a lander do a piece of this work?