Wavy crescent ridges on Mars
Click for full image.
Cool image time! The photo to the right, cropped and reduced to post here, was taken on November 19, 2021 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows what the science team has labeled “Crescentic forms,” which in some ways resemble crescents that I featured in a cool image back in November 2020.
Unlike those earlier crescents, today’s are linked together to form a longer wavy line. Furthermore, today’s crescents include some positive relief, with some parts standing above the surrounding terrain. The earlier crescents were entirely carved out of the ground, forming depressions.
And yet, the method of formation for both must be somewhat similar. I say this based on their location, as shown in the overview map below.
The white cross marks the location of the today’s image, inside the westernmost section of Medusae Fossae Formation, about 250 miles east of the lander InSight and about 280 miles northeast of Curiosity in Gale Crater. The earlier crescents were also inside the Medusae Fossae, but in its eastern sections about 2,300 miles away.
Medusae Fossae is the largest volcanic ash deposit on Mars, and is believed to be the source of most of the planet’s ubiquitous dust. Thus, these crescents are thought to be created when the prevailing winds carve out scallops within the fossae’s thick dust layers as the wind is forced to bend around some more solid object buried in that dust. Think of the water in river rapids flowing around a boulder.
What makes today’s crescents intriguing are their two differing features, their positive relief and the linkage of several into a line. Apparently, there is not as much volcanic ash in this part of Medusae, and instead of carved depressions we’re are seeing the fossil remains of much older wind scallops. Once they were empty, but then became filled with material that ended up harder and more erosion resistant than the dust/ash that surrounded it. When the dust/ash blew away, it left behind that hardened material, the wavy ridges we see today.
At least, that’s my theory. And you should know, I wouldn’t bet a dime on it being correct.
NOTE: Posted late due to the site maintenance today.
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 full image.
Cool image time! The photo to the right, cropped and reduced to post here, was taken on November 19, 2021 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows what the science team has labeled “Crescentic forms,” which in some ways resemble crescents that I featured in a cool image back in November 2020.
Unlike those earlier crescents, today’s are linked together to form a longer wavy line. Furthermore, today’s crescents include some positive relief, with some parts standing above the surrounding terrain. The earlier crescents were entirely carved out of the ground, forming depressions.
And yet, the method of formation for both must be somewhat similar. I say this based on their location, as shown in the overview map below.
The white cross marks the location of the today’s image, inside the westernmost section of Medusae Fossae Formation, about 250 miles east of the lander InSight and about 280 miles northeast of Curiosity in Gale Crater. The earlier crescents were also inside the Medusae Fossae, but in its eastern sections about 2,300 miles away.
Medusae Fossae is the largest volcanic ash deposit on Mars, and is believed to be the source of most of the planet’s ubiquitous dust. Thus, these crescents are thought to be created when the prevailing winds carve out scallops within the fossae’s thick dust layers as the wind is forced to bend around some more solid object buried in that dust. Think of the water in river rapids flowing around a boulder.
What makes today’s crescents intriguing are their two differing features, their positive relief and the linkage of several into a line. Apparently, there is not as much volcanic ash in this part of Medusae, and instead of carved depressions we’re are seeing the fossil remains of much older wind scallops. Once they were empty, but then became filled with material that ended up harder and more erosion resistant than the dust/ash that surrounded it. When the dust/ash blew away, it left behind that hardened material, the wavy ridges we see today.
At least, that’s my theory. And you should know, I wouldn’t bet a dime on it being correct.
NOTE: Posted late due to the site maintenance today.
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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