Evaporating dry ice chunks create gouges on Mars


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Scientists think they have solved the mystery of the gouges that appear seasonally on some hillsides on Mars: Chunks of dry ice that slide down the slope and then evaporate, leaving no trace.

During the martian winter, carbon dioxide ice freezes over parts of the planet’s surface and sublimates back into a gas during the spring thaw. But according to the model presented here today at a meeting of the American Geophysical Union, chunks of warming dry ice may also break off from the crests of dunes and skid down slopes. This is no ordinary tumble—according to the model, the bases of the chunks are continually sublimating, resulting in a hovercraftlike motion that gouges the dune while propelling the ice down slopes. Solid ice that survives to the bottom settles into a pit before dissipating back into the atmosphere.

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One comment

  • Pzatchok

    How does pure dry ice form on the top of those sand dunes?

    As snow or as liquid?

    And if liquid wouldn’t it soak into the sand and possibly solidify inside the sand?
    So if it soaks in then it would be mostly sand and not carbon dioxide. Frozen mud. The CD ice would just hold the ‘dirt’ together and when it thaws or sublimates away wouldn’t it leave piles of sand and or dirt?

    As snow shouldn’t it just sublimate away faster and thus not have a chance to slide down the hill?

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