The High-Resolution Imaging Science Experiment (HiRISE) camera aboard NASA’s Mars Reconnaissance Orbiter (MRO) just can’t stay out of the news. This time around, NASA highlights an image of sand dunes snapped by HiRISE.
The fractured ground is resistant to the very processes that shape the sand dunes above it. NASA scientists have two theories on what makes up the surface in this area. Being resistant to erosion suggests the surface is bedrock shaped by wild swings in temperatures, or bending stresses. Or, it could be a sedimentary layer that may have been wet in the distant past. As it dried, it shrank and fractured. Think of mud cracks, but on a much larger scale.
Here’s another image showing multiple sand dunes and the surface material underneath them.
And here’s the coolest sand dune picture of them all. HiRISE describes their shapes as resembling “raptor claws.”
Here’s a closeup of several of the sand dunes in color.