NASA shares image of unusual Martian sand dunes

Both Earth and Mars have plenty of sand dunes, but while ours are generally light and blend in with their surroundings, those on the Red Planet have a much more varied appearance.

NASA recently shared an image of some sandy features located in Mars' Wirtz Crater and explained what it is that makes them so different from our own.

The agency explains, "Most sand on Earth is made from the mineral quartz, which is white and bright. On Mars, most sand is composed of dark basalt, a volcanic rock. For this reason, dunes on Mars are darker than those on Earth."

NASA further notes that the great tonal contrast represented in the image is the work of, "passing vortices known to us as dust devils. These raise dust off the dune, revealing a darker substrate."

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