The eroding north wall of glacial-filled Harmakhis Valles
Click for original image.
Cool image time! The picture to the right, cropped and reduced to post here, was taken on February 8, 2023 by the high resolution camera on Mars Reconnaissance Orbiter (MRO).
We are looking at the 2,400-foot-high cliff, its lower walls clearly cracking horizontally as they sag downward, with other large sections higher up appearing to have been eroded away in larger pieces.
Yet, the ground below this cliff wall appears to have no debris piles, the kind you would expect below a landslide. Instead, that ground appears to be very glacial in nature, with many linear parallel lines suggesting layers.
The overview map below provides us the context, and an explanation as to where that debris has gone.
The red dot on the overview map near the middle of Harmakhis Valles marks this location, the north wall of that meandering canyon. The canyon itself has been shown with numerous orbital pictures to be filled with a glacier flowing downhill into Hellas Basin.
At 39 degrees south latitude, this cliff is right in the middle of the mid-latitude bands where many glacial features are found on Mars, so it is not surprising that the canyon is glacial filled. A March 19, 2011 MRO context camera picture of this location, showing the entire canyon, makes very clear that glacier. It resembles remarkably many similar glaciers on Earth, such as the Concordia glacier in the Himalayas below the world’s second highest peak, K2.
So, that debris might have fallen from the cliff wall, but it landed on a glacier that, while not appearing active now, at one point in the past was flowing downhill. Over time that glacier carried that debris away.
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 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 and reduced to post here, was taken on February 8, 2023 by the high resolution camera on Mars Reconnaissance Orbiter (MRO).
We are looking at the 2,400-foot-high cliff, its lower walls clearly cracking horizontally as they sag downward, with other large sections higher up appearing to have been eroded away in larger pieces.
Yet, the ground below this cliff wall appears to have no debris piles, the kind you would expect below a landslide. Instead, that ground appears to be very glacial in nature, with many linear parallel lines suggesting layers.
The overview map below provides us the context, and an explanation as to where that debris has gone.
The red dot on the overview map near the middle of Harmakhis Valles marks this location, the north wall of that meandering canyon. The canyon itself has been shown with numerous orbital pictures to be filled with a glacier flowing downhill into Hellas Basin.
At 39 degrees south latitude, this cliff is right in the middle of the mid-latitude bands where many glacial features are found on Mars, so it is not surprising that the canyon is glacial filled. A March 19, 2011 MRO context camera picture of this location, showing the entire canyon, makes very clear that glacier. It resembles remarkably many similar glaciers on Earth, such as the Concordia glacier in the Himalayas below the world’s second highest peak, K2.
So, that debris might have fallen from the cliff wall, but it landed on a glacier that, while not appearing active now, at one point in the past was flowing downhill. Over time that glacier carried that debris away.
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 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
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