Ancient Martian landslides
Click for original image.
Cool image time! The picture to the right, rotated, cropped, reduced, and sharpened to post here, was taken on December 23, 2022 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). The image was labeled “Landslides in Orson Welles Crater” because the full photo shows at least two large and obvious slides, with the biggest shown to the right.
These avalanches are likely ancient because both have craters on them suggesting the material has not moved for a very long time. Yet when both flowed they did so almost like mud, the material moving downhill almost in a single blobby mass. Both have this look, as do many Martian landslides, which I think is why the scientists usually label them mass wasting events.
The white dot in 77-mile-wide Orson Welles Crater in the overview map to the right marks the location of these avalanches. Located on the equator, in Mars’ dry equatorial regions, if near surface ice was involved in this landslide it is now long gone.
Yet such flow features are not unusual in this crater, having been featured in a previous cool image. Nor are they unusual in the meandering 800-mile-long canyon dubbed Shalbatana Vallis that cuts through this crater. We are therefore likely seeing evidence of a time when either liquid water or glaciers were here and carving this canyon. Note too the hypothesized blue lake in Kasei Valles, believed to have existed in the distance past when an ice dam (indicated by the white line) held it in place. The evidence that suggests its existence suggests that water or ice was once in Shalbatana as well.
The black flows in Kasei Valles are hardened flood lava flows that poured through the canyon in mere weeks, long after it was carved.
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, rotated, cropped, reduced, and sharpened to post here, was taken on December 23, 2022 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). The image was labeled “Landslides in Orson Welles Crater” because the full photo shows at least two large and obvious slides, with the biggest shown to the right.
These avalanches are likely ancient because both have craters on them suggesting the material has not moved for a very long time. Yet when both flowed they did so almost like mud, the material moving downhill almost in a single blobby mass. Both have this look, as do many Martian landslides, which I think is why the scientists usually label them mass wasting events.
The white dot in 77-mile-wide Orson Welles Crater in the overview map to the right marks the location of these avalanches. Located on the equator, in Mars’ dry equatorial regions, if near surface ice was involved in this landslide it is now long gone.
Yet such flow features are not unusual in this crater, having been featured in a previous cool image. Nor are they unusual in the meandering 800-mile-long canyon dubbed Shalbatana Vallis that cuts through this crater. We are therefore likely seeing evidence of a time when either liquid water or glaciers were here and carving this canyon. Note too the hypothesized blue lake in Kasei Valles, believed to have existed in the distance past when an ice dam (indicated by the white line) held it in place. The evidence that suggests its existence suggests that water or ice was once in Shalbatana as well.
The black flows in Kasei Valles are hardened flood lava flows that poured through the canyon in mere weeks, long after it was carved.
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