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NASA Reveals Dust Devil Data from Mars

Posted by CowboyNeal on from the round-and-round dept.

saskboy writes "NASA reports that Martian dust devils could be much more destructive than previously considered. You may remember this past April when it was revealed that whirlwinds actually helped the current rovers by cleaning accumulated dust from their solar cells which increased their energy collection efficiency. But after studying the mini-storms more, they realize that the dust and sand particles could cause static electricity discharges, also known as lightning. The high speed grains of sand blowing around at about 30 meters/second (70 miles per hour) are nothing to blink at either, since they can damage astronauts or equipment on the Martian surface. The height of a Martian dust devil can reach 10km (6 miles), which means it's more like the size of a terran tornado."

9 of 116 comments (clear)

  1. A quick question by zegebbers · · Score: 4, Insightful
    From the blurb : "The height of a Martian dust devil can reach 10km (6 miles), which means it's more like the size of a terran tornado."

    Does that mean that a tornado is only on earth? Why are these referred to as "Dust Devils" and not tornadoes generally? Cheers

    --
    Unpretentious Sydney reviews by unqualified Sydney reviewers
  2. At 1/100th earth pressure? by Anonymous Coward · · Score: 4, Informative

    The martian atmosphere is much thinner.. so it isnt gonna be as powerful as "terrestrial hurricanes" for sure..

  3. Thanks :) by HG+Slashdot · · Score: 5, Funny

    But after studying the mini-storms more, they realize that the dust and sand particles could cause static electricity discharges, also known as lightning.
    Thanks :) I have always been wondering what "lightning" is.

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    j0b.org - A famous domain name for sale
  4. Not as powerful as tornadoes... by MadMorf · · Score: 4, Informative

    The height of a Martian dust devil can reach 10km (6 miles), which means it's more like the size of a terran tornado

    But no where near the destructive force of a tornado, which may be why they're calling them dust devils...

    It's less than 1/3 the windspeed and since the atmosphere is less dense the total energy will not be anywhere close...

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    Goofy, Geeky Gifts and More!
    1. Re:Not as powerful as tornadoes... by MadMorf · · Score: 4, Funny

      One more note:

      We may not be able to reliably measure their destructive force because there are no trailer parks for them to tear up...

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      Goofy, Geeky Gifts and More!
    2. Re:Not as powerful as tornadoes... by EvanED · · Score: 4, Funny

      It's not just a matter of not measuring them because of a lack of trailer parks, it is reasonable to conclude from this research originally from The Annals of Improbable Research that the lack of trailer parks actually reduces the occurances of tornadoes.

      Many of the other variables mentioned as possible influences on the frequency of tornadoes, such as camcorder sales, are also substantially lower or in fact zero on Mars.

  5. Grounding to help with static electricity? by Cyclotron_Boy · · Score: 4, Informative

    They bring up an interesting problem in the article about the difficulty of cleaning surfaces after a storm- the triboelectric charges wouldn't necessarily have anywhere to bleed off to. Since Earth's ground is relatively wet, simply sticking a copper rod into the ground provides a good path for stray charges to go. Unfortunately, in a dry soil like that of Mars, grounding rods may not provide the level of protection they might on Earth. On the other hand, the reduced atmospheric pressure and lowered breakdown potential might actually help simpler methods like the charge dissipators (so called "static wicks") on plane wings. Basically, as long as there is a sharp point to help field emission and concentrate the E field in a small volume of space, the excess charge is dissipated into the atmosphere.

  6. "Sand" by luna69 · · Score: 3, Informative

    The OP notes the "he high speed grains of sand blowing around at about 30 meters/second".

    Just to be clear, we're not talking about "sand" in the sense that your average beachgoer thinks of it. The typical size of the dust grains on Mars is a few tens of microns (say 10-30m or so), which is quite a bit smaller than sand, which ranges from a few hundredths of a millimeter to a couple millimeters in size (roughly, using geological definitions).

    --
    No gods, no demons, and no masters. Secular Humanism!
  7. Better whirlwind videos by FleaPlus · · Score: 3, Informative

    A couple of months ago NASA posted some even better videos of the Martian dust devils, available here:

    http://photojournal.jpl.nasa.gov/catalog/PIA07139
    http://photojournal.jpl.nasa.gov/catalog/PIA07140
    http://photojournal.jpl.nasa.gov/catalog/PIA07138

    There's also a rather neat video of Opportunity escaping from the sand trap.