Land of knobs
Click for original image.
Cool image time! The picture to the right, rotated, cropped, reduced, and sharpened to post here, was taken on July 17, 2024 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). Labeled merely as a “terrain sample,” it was likely taken not as part of any specific research project, but to fill a gap in the camera’s schedule in order to maintain its proper temperature.
When the camera team does this, they try to pick interesting targets. In this case, they targeted this 400-foot-high pointy-topped hill. The smoothness of its slopes suggest this hill is made up largely of packed dust, possibly a hardened former dune. This hypothesis seems strengthened by the erosion on the eastern slopes, which appears to be areas where that packed sand has worn or blow away.
Think of sandstone in the American southwest. It is made of sand that has hardened into rock, but wind and water and friction can easily break it back into dust particles, resulting often in the spectacular and weird geological shapes that make the southwest so enticing.
But is this sand?
The white dot on the overview map to the right marks this location, about 330 miles south of the peak of Olympus Mons. The inset shows that this pointy hill is not unique, and is actually just one of hundreds across an east-west strip, dubbed Gigas Sulci, about 380 miles long and 50 to 80 miles wide.
This is truly a land of knobs. If these hills are formed of packed sand, it is likely packed volcanic ash, deposited by the many giant volcanoes that surround it when they were active more than a billion years ago. Since then the ash got compacted and then began eroding away to leave behind the knobs.
It is also quite possible that this is instead hard lava that has eroded away. A third possibility is a combination of volcanic ash and hard lava. The lava could be the knobs, deposited during an eruption and then covered deeply by later volcanic ash. The ash hardened, then eroded away, revealing the more resistant lava hills.
All guesses. But then, it is always fun to guess, as long as you always remind yourself that you are guessing, and need to know more to guess more accurately.
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 original image.
Cool image time! The picture to the right, rotated, cropped, reduced, and sharpened to post here, was taken on July 17, 2024 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). Labeled merely as a “terrain sample,” it was likely taken not as part of any specific research project, but to fill a gap in the camera’s schedule in order to maintain its proper temperature.
When the camera team does this, they try to pick interesting targets. In this case, they targeted this 400-foot-high pointy-topped hill. The smoothness of its slopes suggest this hill is made up largely of packed dust, possibly a hardened former dune. This hypothesis seems strengthened by the erosion on the eastern slopes, which appears to be areas where that packed sand has worn or blow away.
Think of sandstone in the American southwest. It is made of sand that has hardened into rock, but wind and water and friction can easily break it back into dust particles, resulting often in the spectacular and weird geological shapes that make the southwest so enticing.
But is this sand?
The white dot on the overview map to the right marks this location, about 330 miles south of the peak of Olympus Mons. The inset shows that this pointy hill is not unique, and is actually just one of hundreds across an east-west strip, dubbed Gigas Sulci, about 380 miles long and 50 to 80 miles wide.
This is truly a land of knobs. If these hills are formed of packed sand, it is likely packed volcanic ash, deposited by the many giant volcanoes that surround it when they were active more than a billion years ago. Since then the ash got compacted and then began eroding away to leave behind the knobs.
It is also quite possible that this is instead hard lava that has eroded away. A third possibility is a combination of volcanic ash and hard lava. The lava could be the knobs, deposited during an eruption and then covered deeply by later volcanic ash. The ash hardened, then eroded away, revealing the more resistant lava hills.
All guesses. But then, it is always fun to guess, as long as you always remind yourself that you are guessing, and need to know more to guess more accurately.
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.
I do not have a better expectation.
Although there is one slope streak in the bottom left that appears to cross over gullies before puddling. Very usual substance behaving oddly… Super critical fluid?
I”ve been following too many UK sites. First thing I thought of was the British meaning of “knob” :)