Something strange has happened to Mars's polar ice cap. Instead of a uniform, roughly circular blob, like on Earth, the Martian version resembles a pinwheel (left), with dry, spiral troughs separating the ice sheets. There's also Chasma Boreale, the deep, dagger-shaped gouge that cuts across the pinwheel. Scientists had thought that the canyon, which is 2 kilometers deep, was carved by some catastrophic flood in the distant past. Now in two papers published tomorrow in Nature, researchers think they have solved both mysteries. Using a radar survey of the pole (right), which peered under the ice, they conclude that Chasma Boreale wasn't dug out at all. Instead, Martian winds built up the steep, canyon-like walls over millions of years. As for the pinwheel, the team reports that it likewise formed over many millennia, as strong winds pushed apart the dry ice crystals on the surface, much like winds on Earth create sand dunes.

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• Archive

• Neighboring Solar System Resembles Ours
  2010-08-25 10:15:43 - 15 views - 0 reactions
  Astronomers have found the most populous alien solar system yet...
• Martian Volcano Mud May Have Hosted Life
  2010-08-24 17:44:26 - 17 views - 0 reactions
  They're not exactly prime real estate, but Martians may have...
• Simon's Cat in 'The Box'
  2010-08-19 17:50:06 - 22 views - 0 reactions
  It's been a while, but there's a new movie from Simon's Cat.
• Rock, paper, scissors
  2010-08-16 08:07:49 - 35 views - 0 reactions
  
• Odd Galaxy Raises Many Questions
  2010-08-13 08:25:41 - 41 views - 0 reactions
  Something unusual and mysterious has happened to NGC 4696....

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