Cracking ice on Mars?
Click for full image.
Cool image time! The photo to the right, cropped and reduced to post here, was taken on December 7, 2021 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows what the MRO science team dubs “erosion of scalloped terrain” in the northern lowland plains of Mars.
The cracks invoke the polygon cracks one sees in mud as it dries. The circular feature suggests a buried crater whose shape is merely suggested because the cracks are conforming to the underground topography.
Are we looking at dried mud? Maybe, but more likely we are seeing a sheet of ice now sublimating away and cracking as it does so. If you look at the full photo you will see the cracked material also appears to drape itself over several nearby low ridges, something that seems more likely from ice than mud.
The overview map below also suggests this is a buried layer of ice.
The red dot marks the location of this picture. At 42 degrees north latitude, it is well within the region where scientists find ample evidence of ice and glaciers.
The real question then: Why is this ice cracking and eroding away? This far north ice seems to be found everywhere. In glacier country that ice almost always appears robust and thick. Only as you get close to 30 degrees north latitude does it begin to show sublimation features, with all evidence of ice disappearing as you approach the equator.
For this ice to be cracking suggests its protective layer of dust and debris has blown away, exposing the ice to the thin Martian atmosphere and thus allowing it to sublimate away. In fact, this image suggests the bigger mystery is that we don’t find more ice cracking and eroding as we see here. It seems astonishing that most of the glaciers found in the mid-latitudes are all so well protected by a thin layer of dust and debris. Yet it appears they are.
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 full image.
Cool image time! The photo to the right, cropped and reduced to post here, was taken on December 7, 2021 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows what the MRO science team dubs “erosion of scalloped terrain” in the northern lowland plains of Mars.
The cracks invoke the polygon cracks one sees in mud as it dries. The circular feature suggests a buried crater whose shape is merely suggested because the cracks are conforming to the underground topography.
Are we looking at dried mud? Maybe, but more likely we are seeing a sheet of ice now sublimating away and cracking as it does so. If you look at the full photo you will see the cracked material also appears to drape itself over several nearby low ridges, something that seems more likely from ice than mud.
The overview map below also suggests this is a buried layer of ice.
The red dot marks the location of this picture. At 42 degrees north latitude, it is well within the region where scientists find ample evidence of ice and glaciers.
The real question then: Why is this ice cracking and eroding away? This far north ice seems to be found everywhere. In glacier country that ice almost always appears robust and thick. Only as you get close to 30 degrees north latitude does it begin to show sublimation features, with all evidence of ice disappearing as you approach the equator.
For this ice to be cracking suggests its protective layer of dust and debris has blown away, exposing the ice to the thin Martian atmosphere and thus allowing it to sublimate away. In fact, this image suggests the bigger mystery is that we don’t find more ice cracking and eroding as we see here. It seems astonishing that most of the glaciers found in the mid-latitudes are all so well protected by a thin layer of dust and debris. Yet it appears they are.
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
OT: Major corona mass ejection today. Not coming towards the Earth though. But there was simultaneously a “coronal CME” observed moving either directly towards or straight away from Earth, that seems to be unknown thus far.
https://www.youtube.com/watch?v=CvLqhd4fvzY
Such a thing could suddenly wipe out Parker Solar Probe.
All the money that has already been spent, the many missions that have already been sent. And we still don’t know if there is original life on Mars. It almost seems like avoiding the search for it, and yet it is by far the greatest benefit and value that Mars can offer us.
How wide do you suppose the cracks are?
Bill Mullen: Using the scale on the picture, the cracks can’t be more than a few feet across. Generally I’d guess between 1 to 20 feet wide.