Bursting ice sheets on Mars
Click for original image.
Cool image time! The picture to the right, cropped, reduced, and sharpened to post here, was taken on July 31, 2024 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). Labeled simply as a “terrain sample” by the camera team, 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 operating temperature.
In this case the camera team picked a spot in the northern lowland plains at 39 degrees north latitude. What they got was another great piece of evidence of the existence of a lot of near surface ice on Mars, so much so at this location that the craters have become distorted and blobby. The ice in the ground is unstable enough that nothing here can really hold its shape from season to season and from decade to decade.
As I have noted repeatedly in the past six years, MRO data is proving that Mars is not a dry desert like the Sahara, but an icy desert like Antarctica. Except for the planet’s dry tropics below 30 degrees latitude, Mars appears to have a lot of frozen water available relatively near the surface.
The white dot on the overview map to the right marks this location, inside Utopia Planitia, one of several large ancient impact basins on Mars.
The black box in the inset marks the area covered by the picture. For some reason the global mosaic produced from MRO’s context camera missed this particular area, resulting in the white strip across the inset.
The inset tells us however some interesting things about the near surface ice at this location. The string of arrows highlight that lighter streak of terrain, which is also where there is a concentration of these blobby craters. Though the darker surrounding terrain has some scattering of craters, it is mostly smooth and featureless.
The imagery thus suggests one of two possibilities. First, the craters could be volcanic pimples, created when that underground ice sublimates into gas and bursts upward, escaping into the atmosphere at the weakest point, which in this case appears to be along that lighter terrain. Second, the cratered strip could be older terrain. The smoother surrounding terrain has simply been covered by these ice sheets over the eons, obscuring similar craters.
I prefer the first theory, but realize both could be wrong.
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 or from any other book seller. If you want an autographed copy the price is $60 for the hardback and $45 for the paperback, plus $8 shipping for each. Go here for purchasing details. 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
Click for original image.
Cool image time! The picture to the right, cropped, reduced, and sharpened to post here, was taken on July 31, 2024 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). Labeled simply as a “terrain sample” by the camera team, 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 operating temperature.
In this case the camera team picked a spot in the northern lowland plains at 39 degrees north latitude. What they got was another great piece of evidence of the existence of a lot of near surface ice on Mars, so much so at this location that the craters have become distorted and blobby. The ice in the ground is unstable enough that nothing here can really hold its shape from season to season and from decade to decade.
As I have noted repeatedly in the past six years, MRO data is proving that Mars is not a dry desert like the Sahara, but an icy desert like Antarctica. Except for the planet’s dry tropics below 30 degrees latitude, Mars appears to have a lot of frozen water available relatively near the surface.
The white dot on the overview map to the right marks this location, inside Utopia Planitia, one of several large ancient impact basins on Mars.
The black box in the inset marks the area covered by the picture. For some reason the global mosaic produced from MRO’s context camera missed this particular area, resulting in the white strip across the inset.
The inset tells us however some interesting things about the near surface ice at this location. The string of arrows highlight that lighter streak of terrain, which is also where there is a concentration of these blobby craters. Though the darker surrounding terrain has some scattering of craters, it is mostly smooth and featureless.
The imagery thus suggests one of two possibilities. First, the craters could be volcanic pimples, created when that underground ice sublimates into gas and bursts upward, escaping into the atmosphere at the weakest point, which in this case appears to be along that lighter terrain. Second, the cratered strip could be older terrain. The smoother surrounding terrain has simply been covered by these ice sheets over the eons, obscuring similar craters.
I prefer the first theory, but realize both could be wrong.
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 or from any other book seller. If you want an autographed copy the price is $60 for the hardback and $45 for the paperback, plus $8 shipping for each. Go here for purchasing details. 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