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Martian dunes, as far as the eye can see

Martian dunes
Click for full image.

Cool image time! The photo to the right, cropped, reduced, and sharpened to post here, was taken on July 14, 2022 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows the dune filled floor of an unnamed 25-mile-wide ancient and very eroded Martian crater.

These endless dunes — which extend far beyond this photo to cover the entire floor of this crater as well as an overlapping crater to the north that is only slightly smaller — reveal something fundamental about this location: The winds prevail from one direction consistently, from either the north or the south. Closer inspection would likely resolve which way, but I don’t have the knowledge or access to the data to do so.

The overview map below, provides context, and also further information about why these dunes are here.

Overview map

The black dot, about 750 miles due south of Perseverance in Jezero Crater, marks the location of this crater. Note that it is deep within Mars’ very dry equatorial regions, only about 150 miles south of the equator. We will find no near surface ice anywhere nearby, since evidence of ice or glaciers on Mars has so far only been found generally north and south of 30 degrees latitude.

Thus, dust and sand and dunes shall dominate this terrain, with the winds blowing these dunes like waves on an ocean. I suspect that with enough time scientists will detect that these dunes are slowly moving, in unison, in the direction the prevailing winds are blowing them.

There of course are mysteries here. For example, why are the dunes generally aligned both inside and outside small craters? One would think the crater rims would change things, but they don’t. Also, along the left edge of the picture there seems to be a break or disturbance in the line of these dunes. Why?

Genesis cover

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.

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"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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