Martian Pac-Man-like Crater

As much as I hate to admit this, I know what Pac-Man is.  You might say “well who doesn’t know Pac-Man?  I remember quite a lot of life BEFORE Pac-Man or those type games.  Ha, kind of makes me feel a little old.

Beyond that, this is a great image from the HiRISE imager aboard the Mars Reconnaissance Orbiter (MRO).  Be sure to click the image and look at some of the details.  I like the dunes inside the crater.

Here’s the caption from NASA:

This image from NASA’s Mars Reconnaissance Orbiter shows barchan sand dunes, common on Mars and often forming vast dune fields within very large (tens to hundreds of kilometers) impact basins. The regions upwind of barchans are usually devoid of sandy bedforms, so if you were walking in a downwind direction, then the barchans would seem to appear out of nowhere.

As you walk downwind, you would notice the barchans link up (“joining arms”) and eventually slope into featureless sand sheets. We call this progression of dunes a “Herschel-type dune field” named after the first place this sequence was described: Herschel Crater.

But here is something interesting: a barchan dune filling the upwind portion of a small impact crater in a Pac-Man-like shape. This “dune-in-a-crater” is nearly at the highest extent of the field. It is also probably a rare configuration, and over the next few tens of thousands of years the sand will be blown out of the crater.

Image: NASA/JPL-Caltech/Univ. of Arizona



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