A sunflower crater on Mars
Click for original image.
Cool image time! The picture to the right, cropped and reduced to post here, was taken on December 17, 2023 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows what the science team labels a “pedestal crater,” a crater that, because the impact smashed the ground to make it more resistent, when the surrounding terrain eroded away it left the crater sitting high and dry.
In this case the crater is only a few feet higher than that surrounding terrain. In fact, though it looks much deeper than the crater to the northeast, both are so shallow that their depth is below the resolution of MRO’s elevation data.
Both craters however suggest the presence of a lot of near surface ice, which is confirmed by overview map above. The rectangle marks the location, inside the 2,000-mile-long northern mid-latitude strip I dub glacier country, as almost every high resolution picture suggests glacial features and near-surface ice. The crater to the northeast appears filled with glacier debris, while the sunflower-shaped apron around the pedestal crater suggests the impact hit soft ice that splashed away and then hardened.
Though this pedestal crater does not appear to sit high above the plain, the rough edges of its apron illustrate the subsequent erosion. The impact likely stripped away the dust/debris layer that protected the glacial and near-surface ice of that splash apron so that sunlight would cause it to sublimate away. Thus we have that knobby surface at the edges.
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 original image.
Cool image time! The picture to the right, cropped and reduced to post here, was taken on December 17, 2023 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows what the science team labels a “pedestal crater,” a crater that, because the impact smashed the ground to make it more resistent, when the surrounding terrain eroded away it left the crater sitting high and dry.
In this case the crater is only a few feet higher than that surrounding terrain. In fact, though it looks much deeper than the crater to the northeast, both are so shallow that their depth is below the resolution of MRO’s elevation data.
Both craters however suggest the presence of a lot of near surface ice, which is confirmed by overview map above. The rectangle marks the location, inside the 2,000-mile-long northern mid-latitude strip I dub glacier country, as almost every high resolution picture suggests glacial features and near-surface ice. The crater to the northeast appears filled with glacier debris, while the sunflower-shaped apron around the pedestal crater suggests the impact hit soft ice that splashed away and then hardened.
Though this pedestal crater does not appear to sit high above the plain, the rough edges of its apron illustrate the subsequent erosion. The impact likely stripped away the dust/debris layer that protected the glacial and near-surface ice of that splash apron so that sunlight would cause it to sublimate away. Thus we have that knobby surface at the edges.
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