Random Martian ridges on a lava plain
Click for full image.
Cool image time! The photo to the right, cropped and reduced to post here, was taken on December 30, 2021 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). This was a terrain sample image, taken not as part of any specific research project but to fill a gap in the camera’s schedule and thus keep its temperature maintained properly. When the MRO team needs to take such pictures, they try to pick locations that might be interesting and previously unphotographed, but often the location is neither.
In this case this terrain sample captured a flat lava plain interspersed with sinuous ridges going in all directions. On top of this is a scattering of smaller impact craters, which obviously occurred after the lava had flowed and solidified.
What caused the ridges?
My guess is that these ridges are volcanic in origin, based on the location, marked by the blue dot in the overview map to the right. About 1,300 miles to the northeast is the giant volcano Arsia Mons, the southernmost of Mars’ chain of three giant volcanoes. As the lava flowed downward from Arsia, it coated everything, leaving behind on its flanks a smooth lava plain with almost no craters.
Farther from the volcano however the lava only partly covered the craters, and it is in this region where today’s photo is located. In fact, this spot is in the middle of an almost completely inundated fifty-mile-wide unnamed crater, the rim barely visible.
At the same time Arsia Mons was laying down this flood lava, the volcano was also pushing upward, which explains the parallel fissures pointing away from the volcano north and south of this image.
The ridges could possibly be related to the solidification process when the lava hardened. Think of the cracks that form in mud when it dries. The mud contracts as it dries, causing random polygon cracks. In this case, the lava instead expanded as it hardened, causing ridges to form at weak points where the lava cracked.
I am guessing of course. There are other possibilities that more knowledgeable people than I could put forth.
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 full image.
Cool image time! The photo to the right, cropped and reduced to post here, was taken on December 30, 2021 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). This was a terrain sample image, taken not as part of any specific research project but to fill a gap in the camera’s schedule and thus keep its temperature maintained properly. When the MRO team needs to take such pictures, they try to pick locations that might be interesting and previously unphotographed, but often the location is neither.
In this case this terrain sample captured a flat lava plain interspersed with sinuous ridges going in all directions. On top of this is a scattering of smaller impact craters, which obviously occurred after the lava had flowed and solidified.
What caused the ridges?
My guess is that these ridges are volcanic in origin, based on the location, marked by the blue dot in the overview map to the right. About 1,300 miles to the northeast is the giant volcano Arsia Mons, the southernmost of Mars’ chain of three giant volcanoes. As the lava flowed downward from Arsia, it coated everything, leaving behind on its flanks a smooth lava plain with almost no craters.
Farther from the volcano however the lava only partly covered the craters, and it is in this region where today’s photo is located. In fact, this spot is in the middle of an almost completely inundated fifty-mile-wide unnamed crater, the rim barely visible.
At the same time Arsia Mons was laying down this flood lava, the volcano was also pushing upward, which explains the parallel fissures pointing away from the volcano north and south of this image.
The ridges could possibly be related to the solidification process when the lava hardened. Think of the cracks that form in mud when it dries. The mud contracts as it dries, causing random polygon cracks. In this case, the lava instead expanded as it hardened, causing ridges to form at weak points where the lava cracked.
I am guessing of course. There are other possibilities that more knowledgeable people than I could put forth.
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