A Piece of Mars: This 0.96×0.48 km (0.6×0.3 mi) scene shows a bit of a south polar dune field. The more recently-active dark sand is rippled, but there are bright splotches where something else has happened. Presumably it’s ground ice that sublimated away explosively, as happens at many high latitude locations on Mars, only here the dunes are stabilized enough that those spots aren’t eroded away by wind activity every summer. Because the dunes aren’t active, their crests have diminished to subtle bumps on the landscape (would you even know they were dunes if I hadn’t told you? Look at the whole HiRISE image to be sure!) (HiRISE ESP_013224_1080, NASA/JPL/Univ. of Arizona)

Comments (1)

  1. Wild and weird! How confident are you of that theory of their formation?

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