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A Martian rock with holes

A Martian rock with holes
Click for original image.

Cool image time! The picture to the right, cropped, reduced, and sharpened to post here, was taken on April 13, 2024 by the high resolution camera on the Mars rover Perseverance.

The largest rock in the picture is probably only one or a few feet or so across. It has two holes, one very visible in the center and a second less obvious in the shadow on the right. What makes the obvious hole most intriguing is that it appears it was formerly entirely enclosed by the boulder, and was exposed when a section broke off. That section is the smaller rock in the foreground. I wonder if the Perseverance team will bring the rover around to get a view of that smaller rock, to see if it has its own corresponding part of this hole.

Note the smoothness of the rocks. This smoothness is very similar to what Curiosity saw when it was either on the floor of Gale Crater, or at the base of Mount Sharp. In both cases that smoothness suggests either flowing water or glacial ice erosion, like the smooth cobbles one routinely finds in streambeds or in the moraines of glaciers.

As Curiosity climbed Mount Sharp the smoothness was replaced with a delicate flaky fleecework indicating many layers but little violent erosion capable of smoothing the surface (see for example the images here and here). It appears Perseverance is still low enough in Jezero Crater to be within the ancient active region, formed from flowing water or ice.

As for the holes, my guess is that this rock formed from lava, and the holes are what geologists call “vugs”, bubbles formed within the lava as it solidified.

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.

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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