The pimpled floor of Isidis Basin on Mars
Click for original image.
Cool image time! The picture to the right, cropped, reduced, and sharpened to post here, was taken on May 21, 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 chosen by the camera team to fill a gap in the camera’s schedule in order to maintain its proper temperature.
When they do this they try to pick a target that is somewhat interesting, though it is not always possible. In this case it appears they succeeded in capturing a location filled with lots of puzzling stuff, including low 60-to-80-foot-high mesas with either flat- or hollow-tops, shallow craters that appear almost buried, and other craters that appear so deep and shadowed that it is even possible these are skylights into underground caves.
In between these features the flat landscape has a scattering of ripple dunes, all oriented in the same direction and thus implying that the prevailing winds are or were blowing from the northeast to the southwest.
The red dot on the overview map to the right marks the location, inside Isidis Basin, the third largest basin on Mars and believed to have been formed by a gigantic impact about four billion years ago. The inset shows that the general landscape on the floor of Isidis is similar to the picture above, a scattering of small mesas interspersed with craters.
How did this surface form? It is believed that the floor of Isidis is mostly flood lava left over from that impact. The mesas could be small volcanic pimples from which lava bubbled upward before it hardened. Or they could be the top of the original topography, now buried by that flood lava. This flooding clearly covered the shallow craters.
The small and deep craters however likely came much later. They could have formed by impacts that were able to drill into the lava deeply. And while it is also possible we are looking into pits formed simply by the collapse of the surface into underground voids, the randomness of these pits makes that less likely. If there was an underground lava tube, the pits would line up. Here they do not.
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 May 21, 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 chosen by the camera team to fill a gap in the camera’s schedule in order to maintain its proper temperature.
When they do this they try to pick a target that is somewhat interesting, though it is not always possible. In this case it appears they succeeded in capturing a location filled with lots of puzzling stuff, including low 60-to-80-foot-high mesas with either flat- or hollow-tops, shallow craters that appear almost buried, and other craters that appear so deep and shadowed that it is even possible these are skylights into underground caves.
In between these features the flat landscape has a scattering of ripple dunes, all oriented in the same direction and thus implying that the prevailing winds are or were blowing from the northeast to the southwest.
The red dot on the overview map to the right marks the location, inside Isidis Basin, the third largest basin on Mars and believed to have been formed by a gigantic impact about four billion years ago. The inset shows that the general landscape on the floor of Isidis is similar to the picture above, a scattering of small mesas interspersed with craters.
How did this surface form? It is believed that the floor of Isidis is mostly flood lava left over from that impact. The mesas could be small volcanic pimples from which lava bubbled upward before it hardened. Or they could be the top of the original topography, now buried by that flood lava. This flooding clearly covered the shallow craters.
The small and deep craters however likely came much later. They could have formed by impacts that were able to drill into the lava deeply. And while it is also possible we are looking into pits formed simply by the collapse of the surface into underground voids, the randomness of these pits makes that less likely. If there was an underground lava tube, the pits would line up. Here they do not.
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