A ridge that runs right over a Martian mesa
Click for original image.
Cool image time! The picture to the right, cropped, reduced, and sharpened to post here, was taken on April 5, 2024 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). I have cropped it to focus on the geological feature that likely attracted the interest of the scientists who requested this photo, the mesa that has a ridgeline running over it as if the mesa was not even there.
The mesa is about 80 feet high on its west side, but on its east the ground continues to drop away more than 500 feet as you move 2.5 miles to the east. Based on how the MRO science team interprets the colors [pdf] in the color strip, the orange areas are likely dust while the greenish surface suggests coarser sand and boulders. This conclusion is reinforced if you look at the parallel dunes south of the mesa. The dunes are yellow-orange (dust) while the ground between is yellow-green (sand), exactly what you expect with the larger coarser material settling in lower elevations.
The overview map provides the context, which might help explain the ridgeline.
The white dot on the overview map to the right marks the location, with the small rectangle in the inset indicating the area covered by the picture above. The inset shows the surrounding terrain, and is anotated to give some elevation perspective. The low point to the east of the mesa is noted, while the dotted circle indicates the rim of this roughly ten-mile-wide depression, inside a much larger basin about 70 miles in diameter.
This region is filled with many parallel fissures running northeast-to-southwest and illustrated most by the two Nili Fossae fissures. It is also a region known for having a lot of interesting minerals, which is one reason why the scientists chose to land Perseverance in Jezero Crater to the east. The hope is to send the rover west beyond the crater rim into this mineral-rich region to get some data.
The fissures or cracks are thought to have been created by the giant impact about four billion years ago that formed Isidis Basin to the east. The ridge, which also runs northeast-to-southeast, is probably another crack that was later filled with lava, forming what geologists call a dike, made of more resistent material that became a ridge as the surrounding terrain eroded away. As the ground disappeared around the mesa, the ridge became evident.
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, cropped, reduced, and sharpened to post here, was taken on April 5, 2024 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). I have cropped it to focus on the geological feature that likely attracted the interest of the scientists who requested this photo, the mesa that has a ridgeline running over it as if the mesa was not even there.
The mesa is about 80 feet high on its west side, but on its east the ground continues to drop away more than 500 feet as you move 2.5 miles to the east. Based on how the MRO science team interprets the colors [pdf] in the color strip, the orange areas are likely dust while the greenish surface suggests coarser sand and boulders. This conclusion is reinforced if you look at the parallel dunes south of the mesa. The dunes are yellow-orange (dust) while the ground between is yellow-green (sand), exactly what you expect with the larger coarser material settling in lower elevations.
The overview map provides the context, which might help explain the ridgeline.
The white dot on the overview map to the right marks the location, with the small rectangle in the inset indicating the area covered by the picture above. The inset shows the surrounding terrain, and is anotated to give some elevation perspective. The low point to the east of the mesa is noted, while the dotted circle indicates the rim of this roughly ten-mile-wide depression, inside a much larger basin about 70 miles in diameter.
This region is filled with many parallel fissures running northeast-to-southwest and illustrated most by the two Nili Fossae fissures. It is also a region known for having a lot of interesting minerals, which is one reason why the scientists chose to land Perseverance in Jezero Crater to the east. The hope is to send the rover west beyond the crater rim into this mineral-rich region to get some data.
The fissures or cracks are thought to have been created by the giant impact about four billion years ago that formed Isidis Basin to the east. The ridge, which also runs northeast-to-southeast, is probably another crack that was later filled with lava, forming what geologists call a dike, made of more resistent material that became a ridge as the surrounding terrain eroded away. As the ground disappeared around the mesa, the ridge became evident.
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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