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Jun 11 2013

Mars has its own hovercraft?

PIA17260_ip

Click for very hi res image

How did these amazing gullies on the Red Planet form? Go below the fold for the intriguing answer:

NASA — Several types of downhill flow features have been observed on Mars. This image from the High Resolution Imaging Science Experiment (HiRISE) camera on NASA’s Mars Reconnaissance Orbiter is an example of a type called “linear gullies.” Linear gullies are characterized by relatively constant width and by raised banks or levees along the sides. Unlike gullies caused by water-lubricated flows on Earth and possibly on Mars, they don’t have aprons of debris at the downhill end of the channel. The grooves shown here, on the side of a large sand dune inside Russell Crater, are the longest linear gullies known, extending almost 1.2 miles (2 kilometers) down this dune slope.

New research points to chunks of frozen carbon dioxide, commonly called “dry ice,” creating linear gullies by gliding down sandy slopes on cushions of carbon-dioxide gas sublimating from the dry ice. Linear gullies are on mid-latitude sandy slopes, where the ground is covered with carbon-dioxide frost in Martian winter. Before-and-after pairs of HiRISE images indicate that the linear gullies are formed during early spring. Some linear gullies — such as the ones in the magnified section of this image shown as Figure 1 — have pits at the downhill end that could be caused by a block of dry ice ending its slide and resting in place as it sublimates away.

This image is a portion of the HiRISE exposure catalogued as PSP_001440_1255 taken on Nov. 16, 2006, at 54.25 degrees south latitude, 12.92 degrees east longitude.

7 comments

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  1. 1
    Zinc Avenger (Sarcasm Tags 3.0 Compliant)

    Anyone who thinks a universe without a God can’t have wonder is not paying attention.

  2. 2
    mikey

    But could these hovercrafts have been full of eels?

  3. 3
    machintelligence

    Hovercraft, hell! Mars has skiers!

    Now I want to go schuss a sand dune.

  4. 4
    Aliasalpha

    Looks like Dark Helmet’s men have been combing the desert again.

  5. 5
    lou Jost

    So why do they all start off exactly at the crest of the dune?

  6. 6
    Stephen "DarkSyde" Andrew

    Alia I’m stealing that and calling it my own. Lou, not sure but I believe what happens is the dunes move over time, not unlike waves in some respects if you visualize time elapsed, the chunks of dry ice do not move so handily, they become exposed somewhat like rocks on earth leaving an erosion peak of dry ice sometimes and when it’s finally exposed and sublimates enough, it can roll or slide the rest of the way down a dune’s crest.

  7. 7
    Aliasalpha

    Heh well if you’re going to steal it, you might as well have the video: http://youtu.be/MtkK3eijBso

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