Knobs on the floor of a Martian caldera
Click for original image.
Cool image time! The picture to the right, rotated, cropped, reduced, and sharpened to post here, was taken on February 14, 2023 by the high resolution camera on Mars Reconnaissance Orbiter (MRO) and shows what the scientists have dubbed as “enigmatic knobs” located on the caldera floor of a Martian shield volcano.
The knobs themselves, while puzzling, aren’t that interesting on their own. They are no more than 100 to 200 feet high, and are relatively featureless. Since most lack a pit at their peaks, they are probably not some form of small volcanic vent, though this conclusion is uncertain. The location, at about 30 degrees south latitude, suggests the faint possibility of near surface ice, which could make these mud volcanoes, or a very specific Arctic-type permafrost mound dubbed pingos, but once again the lack of any central pit at their peaks makes these origins also doubtful.
What the knobs however revealed to me was a giant Martian shield volcano I had never noticed before, even though it was hiding in plain sight.
The red dot on the overview map to the right marks this location, inside the caldera of the shield volcano Hadriacus Mons. Martian shield volcanoes tend to be relatively flat, as their lava flows out slowly over a long time, covering a wide area. In the case of Hadriacus, it is so flat that I never noticed its existence previously on the upper slopes leading down into Hellas Basin, the death valley of Mars. And yet, it is almost three hundred miles across, with a caldera forty miles wide standing more than 50,000 feet above the floor of Hellas.
The many drainage channels flowing down its southwest flanks into Hellas are thought [pdf] to have been formed by a combination of volcanic, fluvial, and catastrophic flood events, all taking place more than 1.4 billion years ago. Strangely, none of these drainage channels flow into DaoValles. Instead, they drain directly into the floor of Hellas to the west of Dao.
Moreover, in recognizing the existence of Hadriacus the origins of Dao Valles come into focus. While it is appears to be filled with glacial features today, its sudden beginning on the flanks of Hadriacus suggests it might have originally formed as a volcanic vent and lava tube, which was subsequently carved wider with its roof removed by ice/liquid water processes.
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. from any other book seller, or direct from my ebook publisher, ebookit.
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 February 14, 2023 by the high resolution camera on Mars Reconnaissance Orbiter (MRO) and shows what the scientists have dubbed as “enigmatic knobs” located on the caldera floor of a Martian shield volcano.
The knobs themselves, while puzzling, aren’t that interesting on their own. They are no more than 100 to 200 feet high, and are relatively featureless. Since most lack a pit at their peaks, they are probably not some form of small volcanic vent, though this conclusion is uncertain. The location, at about 30 degrees south latitude, suggests the faint possibility of near surface ice, which could make these mud volcanoes, or a very specific Arctic-type permafrost mound dubbed pingos, but once again the lack of any central pit at their peaks makes these origins also doubtful.
What the knobs however revealed to me was a giant Martian shield volcano I had never noticed before, even though it was hiding in plain sight.
The red dot on the overview map to the right marks this location, inside the caldera of the shield volcano Hadriacus Mons. Martian shield volcanoes tend to be relatively flat, as their lava flows out slowly over a long time, covering a wide area. In the case of Hadriacus, it is so flat that I never noticed its existence previously on the upper slopes leading down into Hellas Basin, the death valley of Mars. And yet, it is almost three hundred miles across, with a caldera forty miles wide standing more than 50,000 feet above the floor of Hellas.
The many drainage channels flowing down its southwest flanks into Hellas are thought [pdf] to have been formed by a combination of volcanic, fluvial, and catastrophic flood events, all taking place more than 1.4 billion years ago. Strangely, none of these drainage channels flow into DaoValles. Instead, they drain directly into the floor of Hellas to the west of Dao.
Moreover, in recognizing the existence of Hadriacus the origins of Dao Valles come into focus. While it is appears to be filled with glacial features today, its sudden beginning on the flanks of Hadriacus suggests it might have originally formed as a volcanic vent and lava tube, which was subsequently carved wider with its roof removed by ice/liquid water processes.
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. from any other book seller, or direct from my ebook publisher, ebookit. 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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