Gullies on a crater wall in the icy north of Mars
Click for original image.
Cool image time! The picture to the right, cropped, reduced, and sharpened to post here, was taken on July 4, 2025 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows the lower right quadrant of a five-mile-wide unnamed crater in the high northern mid-latitudes of Mars.
The science team in its label for this picture focuses on the gullies visible on the crater’s interior wall. To my Earth-bound eye, these gullies look like recent erosion caused by underground ice sublimating into gas, causing the surface to collapse downward into the crater. This however is a purely uneducated guess.
The floor of the crater however shows features that resemble glacial fill, seen in numerous high latitude craters on Mars. This is not surprising, as the crater is located at 59 degrees north latitude, close enough to the pole for there to be a lot of near surface ice to be present.
The white dot on the overview map to the right marks the location, on the far north edge of Utopia Basin, one of several of Mars’ very large ancient impact basins.
At this latitude the entire surface of the terrain looks as if it is shaped by the presence of a near surface ice sheet. For example, in the inset we can see a large splash apron surrounding this crater, as if the impact had landed on ground impregnated with ice that quickly melted, splashed outward, and then refroze.
In the case of the gullies, researchers are still trying to figure out the geological processes that form them. They are found in many places in the Martian mid-latitudes. While initially believed to be related to the sublimation of underground ice, more recent research suggests they are formed by the seasonal dry ice frost cycle that in the high latitudes has carbon dioxide condense to fall as snow in autumn and then sublimate away in the spring.
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 July 4, 2025 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows the lower right quadrant of a five-mile-wide unnamed crater in the high northern mid-latitudes of Mars.
The science team in its label for this picture focuses on the gullies visible on the crater’s interior wall. To my Earth-bound eye, these gullies look like recent erosion caused by underground ice sublimating into gas, causing the surface to collapse downward into the crater. This however is a purely uneducated guess.
The floor of the crater however shows features that resemble glacial fill, seen in numerous high latitude craters on Mars. This is not surprising, as the crater is located at 59 degrees north latitude, close enough to the pole for there to be a lot of near surface ice to be present.
The white dot on the overview map to the right marks the location, on the far north edge of Utopia Basin, one of several of Mars’ very large ancient impact basins.
At this latitude the entire surface of the terrain looks as if it is shaped by the presence of a near surface ice sheet. For example, in the inset we can see a large splash apron surrounding this crater, as if the impact had landed on ground impregnated with ice that quickly melted, splashed outward, and then refroze.
In the case of the gullies, researchers are still trying to figure out the geological processes that form them. They are found in many places in the Martian mid-latitudes. While initially believed to be related to the sublimation of underground ice, more recent research suggests they are formed by the seasonal dry ice frost cycle that in the high latitudes has carbon dioxide condense to fall as snow in autumn and then sublimate away in the spring.
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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