Cracking glaciers on Mars
Click for full image.
Cool image time! The photo to the right, cropped and reduced to post here, was released today as the picture of the day for the high resolution camera on Mars Reconnaissance Orbiter (MRO). Located in the 2,000 long northern mid-latitude strip that I dub Mars’ glacier country, it shows many of the numerous glacial features that are routinely found in images taken in this region. According to Dan Berman, senior scientist at the Planetary Science Institute in Arizona, who wrote the caption,
This observation shows a lobe-shaped debris apron emanating from a massif (shown in the upper left of the image) in the Protonilus Mensae region in the Northern Hemisphere of Mars. These aprons are composed of nearly pure water ice with a layer of debris on the surface protecting the ice from sublimation (going directly from a solid to gaseous state). This image shows different terrain types on the apron that indicate the presence and flow of ice, from smoother polygonal terrain closer to the massif, to rougher, patterned ground commonly called “brain terrain.” Also visible on the apron are a series of linear pits.
Protonilus Mensae is the central mensae region in that mid-latitude strip of glaciers.The overview map below shows the location of this photo in that region. Also below is a close-up of the linear pits and cracked terrain surrounding that oblong mound, as indicated by the white rectangle.
Click for full image.
The white cross marks the location of the photo above. If you do a search on Behind the Black for “glaciers” or “glacier country,” you will find numerous images in this region, all showing similar glacial terrain. The latitude of the region ranges from 30 to 47 degrees, with this particular spot at 44 degrees. At that latitude almost every low spot will show glacial features, as noted by Berman above.
The close-up of the area in the rectangle is also to the right. The many polygonal cracks and linear pits surrounding this mound suggest that the buried glaciers at this location are sublimating away. Think of the polygonal cracks that appear in drying mud. A similar phenomenon is occurring here. At the ice sublimates into gas, the remaining solid ice cracks and shrinks, producing cracks and voids. In some cases the voids become large enough that they form the linear pits that surround this mound.
This pits are also comparable to the rifts and cracks that mountain climbers must deal with when they need to traverse Earth glaciers. The difference is that on Earth those glaciers are very active, with the ice moving and new cracks forming regularly.
On Mars these glaciers are thought to be no longer growing or moving. If any change is occurring it is sublimation and shrinking, though it remains unclear whether the glaciers in Mars’ mid-latitudes are in an overall steady state, or are growing or shrinking.
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.
Click for full image.
Cool image time! The photo to the right, cropped and reduced to post here, was released today as the picture of the day for the high resolution camera on Mars Reconnaissance Orbiter (MRO). Located in the 2,000 long northern mid-latitude strip that I dub Mars’ glacier country, it shows many of the numerous glacial features that are routinely found in images taken in this region. According to Dan Berman, senior scientist at the Planetary Science Institute in Arizona, who wrote the caption,
This observation shows a lobe-shaped debris apron emanating from a massif (shown in the upper left of the image) in the Protonilus Mensae region in the Northern Hemisphere of Mars. These aprons are composed of nearly pure water ice with a layer of debris on the surface protecting the ice from sublimation (going directly from a solid to gaseous state). This image shows different terrain types on the apron that indicate the presence and flow of ice, from smoother polygonal terrain closer to the massif, to rougher, patterned ground commonly called “brain terrain.” Also visible on the apron are a series of linear pits.
Protonilus Mensae is the central mensae region in that mid-latitude strip of glaciers.The overview map below shows the location of this photo in that region. Also below is a close-up of the linear pits and cracked terrain surrounding that oblong mound, as indicated by the white rectangle.
Click for full image.
The white cross marks the location of the photo above. If you do a search on Behind the Black for “glaciers” or “glacier country,” you will find numerous images in this region, all showing similar glacial terrain. The latitude of the region ranges from 30 to 47 degrees, with this particular spot at 44 degrees. At that latitude almost every low spot will show glacial features, as noted by Berman above.
The close-up of the area in the rectangle is also to the right. The many polygonal cracks and linear pits surrounding this mound suggest that the buried glaciers at this location are sublimating away. Think of the polygonal cracks that appear in drying mud. A similar phenomenon is occurring here. At the ice sublimates into gas, the remaining solid ice cracks and shrinks, producing cracks and voids. In some cases the voids become large enough that they form the linear pits that surround this mound.
This pits are also comparable to the rifts and cracks that mountain climbers must deal with when they need to traverse Earth glaciers. The difference is that on Earth those glaciers are very active, with the ice moving and new cracks forming regularly.
On Mars these glaciers are thought to be no longer growing or moving. If any change is occurring it is sublimation and shrinking, though it remains unclear whether the glaciers in Mars’ mid-latitudes are in an overall steady state, or are growing or shrinking.
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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