Springtime on Martian dunes near the north pole
Cool image time! The photo to the right, rotated and cropped to post here, was taken by the high resolution camera on Mars Reconnaissance Orbiter (MRO) on April 27, 2021. It shows a strange scattering of dunes on a flat plain. The red at the top of each dune probably indicates exposed dust and sand. The white fringe is likely either water frost or the leftover mantle of dry ice that is deposited in the polar regions each winter down to 60 degrees latitude, and disappears with the coming of spring, sublimating back into carbon dioxide gas.
There are a lot of puzzles here. The overview map below provides some context, but only some.
This location, marked by the black cross, is at 76 degrees north latitude, putting it only about 800 miles away from the north pole. It also sits in the vast sea of sand dunes that circles the north polar ice cap, in an area where dunes cover between 11% to 79% of the surface.
Why these dunes however should be so individual and scattered, with some aligned in a string, is not clear. Nor is it presently understood why the north polar icecap of Mars is surrounded by this ring of sand dunes, while the south polar icecap is not. There are dunes in the south, but no where as many or gathered for endless trackless distances.
Locations such as this are regularly monitored by scientists using MRO to see if the changing seasons cause any changes to the dunes. The coming and going of the dry ice mantle could cause small avalanches and erosion in the dunes.
At the same time, the coldness at this location and the presence of water ice in the ground means that changes are not easy. While these are sand dunes they are not made of loose flowing sand. It has been hardened, and will only break apart with significant stress.
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 print edition can be purchased at Amazon. from any other book seller, or direct from my ebook publisher, ebookit.
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
Cool image time! The photo to the right, rotated and cropped to post here, was taken by the high resolution camera on Mars Reconnaissance Orbiter (MRO) on April 27, 2021. It shows a strange scattering of dunes on a flat plain. The red at the top of each dune probably indicates exposed dust and sand. The white fringe is likely either water frost or the leftover mantle of dry ice that is deposited in the polar regions each winter down to 60 degrees latitude, and disappears with the coming of spring, sublimating back into carbon dioxide gas.
There are a lot of puzzles here. The overview map below provides some context, but only some.
This location, marked by the black cross, is at 76 degrees north latitude, putting it only about 800 miles away from the north pole. It also sits in the vast sea of sand dunes that circles the north polar ice cap, in an area where dunes cover between 11% to 79% of the surface.
Why these dunes however should be so individual and scattered, with some aligned in a string, is not clear. Nor is it presently understood why the north polar icecap of Mars is surrounded by this ring of sand dunes, while the south polar icecap is not. There are dunes in the south, but no where as many or gathered for endless trackless distances.
Locations such as this are regularly monitored by scientists using MRO to see if the changing seasons cause any changes to the dunes. The coming and going of the dry ice mantle could cause small avalanches and erosion in the dunes.
At the same time, the coldness at this location and the presence of water ice in the ground means that changes are not easy. While these are sand dunes they are not made of loose flowing sand. It has been hardened, and will only break apart with significant stress.
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 print edition can be purchased at Amazon. from any other book seller, or direct from my ebook publisher, ebookit. 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
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