Mesa in the Martian northern lowlands
Click for full image.
Cool image time! The photo to the right, cropped and reduced to post here, was taken on February 2, 2022 by the high resolution camera on Mars Reconnaissance Orbiter (MRO) and shows a mesa sticking up on the relatively flat and featureless northern lowland plains in Utopia Planitia, the second largest impact basin on Mars.
The full image shows three such mesas. Though pictures taken in the northern lowlands of Utopia tend to show evidence of buried ice or glaciers, the impression I get from this picture is one of dryness. If there is any ice here, it is below ground. And even that seems unlikely. The surface surrounding nearby craters does not have that squishy and slushy look that is seen in the north when an impact occurred on near surface ice. Instead, the ground looks solid.
The overview map below reinforces this impression.
The red dot on the 30th parallel north of Isidis Basin marks the location of this mesa. At that latitude the mesa is at the very southern edge of the 30-60 degree mid-latitude bands where scientists have found many Martian glaciers. While a few spots south of that latitude have been identified where there might be ice, they are few and also uncertain. The general trend is dryness once one gets to 30 degrees.
These mesas are intriguing because they suggest that the surface here was once higher, and that a significant amount of material has been removed over the eons, with these mesas somehow surviving. This hypothesis is strengthened by what look like two pedestal craters just to the east of the mesa. Pedestal craters are thought to be impact spots that resist erosion because the impact smashes the material at the site and makes it more resistant to erosion. When the surrounding terrain erodes away, the crater remains.
What swept those top layers away? A first guess is that once there was underground ice here, and with its slow loss over time the surface dropped away.
Now available in hardback and paperback as well as ebook!
From the press release: In this ground-breaking new history of early America, historian Robert Zimmerman not only exposes the lie behind The New York Times 1619 Project that falsely claims slavery is central to the history of the United States, he also provides profound lessons about the nature of human societies, lessons important for Americans today as well as for all future settlers on Mars and elsewhere in space.
Conscious Choice: The origins of slavery in America and why it matters today and for our future in outer space, is a riveting page-turning story that documents how slavery slowly became pervasive in the southern British colonies of North America, colonies founded by a people and culture that not only did not allow slavery but in every way were hostile to the practice.
Conscious Choice does more however. In telling the tragic history of the Virginia colony and the rise of slavery there, Zimmerman lays out the proper path for creating healthy societies in places like the Moon and Mars.
“Zimmerman’s ground-breaking history provides every future generation the basic framework for establishing new societies on other worlds. We would be wise to heed what he says.” —Robert Zubrin, founder of founder of the Mars Society.
All editions are available at Amazon, Barnes & Noble, and all book vendors, with the ebook priced at $5.99 before discount. The ebook can also be purchased direct from my ebook publisher, ebookit, in which case you don't support the big tech companies and I get a bigger cut much sooner.
Autographed printed copies are also available at discount directly from me (hardback $24.95; paperback $14.95; Shipping cost for either: $5.00). Just email me at zimmerman @ nasw dot org.
Click for full image.
Cool image time! The photo to the right, cropped and reduced to post here, was taken on February 2, 2022 by the high resolution camera on Mars Reconnaissance Orbiter (MRO) and shows a mesa sticking up on the relatively flat and featureless northern lowland plains in Utopia Planitia, the second largest impact basin on Mars.
The full image shows three such mesas. Though pictures taken in the northern lowlands of Utopia tend to show evidence of buried ice or glaciers, the impression I get from this picture is one of dryness. If there is any ice here, it is below ground. And even that seems unlikely. The surface surrounding nearby craters does not have that squishy and slushy look that is seen in the north when an impact occurred on near surface ice. Instead, the ground looks solid.
The overview map below reinforces this impression.
The red dot on the 30th parallel north of Isidis Basin marks the location of this mesa. At that latitude the mesa is at the very southern edge of the 30-60 degree mid-latitude bands where scientists have found many Martian glaciers. While a few spots south of that latitude have been identified where there might be ice, they are few and also uncertain. The general trend is dryness once one gets to 30 degrees.
These mesas are intriguing because they suggest that the surface here was once higher, and that a significant amount of material has been removed over the eons, with these mesas somehow surviving. This hypothesis is strengthened by what look like two pedestal craters just to the east of the mesa. Pedestal craters are thought to be impact spots that resist erosion because the impact smashes the material at the site and makes it more resistant to erosion. When the surrounding terrain erodes away, the crater remains.
What swept those top layers away? A first guess is that once there was underground ice here, and with its slow loss over time the surface dropped away.
Now available in hardback and paperback as well as ebook!
From the press release: In this ground-breaking new history of early America, historian Robert Zimmerman not only exposes the lie behind The New York Times 1619 Project that falsely claims slavery is central to the history of the United States, he also provides profound lessons about the nature of human societies, lessons important for Americans today as well as for all future settlers on Mars and elsewhere in space.
Conscious Choice: The origins of slavery in America and why it matters today and for our future in outer space, is a riveting page-turning story that documents how slavery slowly became pervasive in the southern British colonies of North America, colonies founded by a people and culture that not only did not allow slavery but in every way were hostile to the practice.
Conscious Choice does more however. In telling the tragic history of the Virginia colony and the rise of slavery there, Zimmerman lays out the proper path for creating healthy societies in places like the Moon and Mars.
“Zimmerman’s ground-breaking history provides every future generation the basic framework for establishing new societies on other worlds. We would be wise to heed what he says.” —Robert Zubrin, founder of founder of the Mars Society.
All editions are available at Amazon, Barnes & Noble, and all book vendors, with the ebook priced at $5.99 before discount. The ebook can also be purchased direct from my ebook publisher, ebookit, in which case you don't support the big tech companies and I get a bigger cut much sooner.
Autographed printed copies are also available at discount directly from me (hardback $24.95; paperback $14.95; Shipping cost for either: $5.00). Just email me at zimmerman @ nasw dot org.
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