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Fwd = Rectangular Ridges on Mars

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  • Frits Westra
    Forwarded by: fwestra@hetnet.nl (Frits Westra) URL: http://antwrp.gsfc.nasa.gov/apod/ap021001.html Original Date: Thu, 3 Oct 2002 05:50:34
    Message 1 of 1 , Oct 3, 2002
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      Forwarded by: fwestra@... (Frits Westra)
      URL: http://antwrp.gsfc.nasa.gov/apod/ap021001.html
      Original Date: Thu, 3 Oct 2002 05:50:34 -0500

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      2002 October 1

      Rectangular Ridges on Mars
      Credit: Malin Space Science Systems, MGS, JPL, NASA

      Explanation: What could cause rectangular ridges on Mars? As data
      flows in from the two spacecraft currently orbiting Mars,
      surface structures are seen that are not immediately understood. These
      structures pose puzzles that planetary geologists are eager to solve,
      as they might provide clues to past processes that have shaped
      Mars over billions of years. On the right of the above image
      is an unusual array of ridges first spotted in Mariner 9 data in
      1972. A ridge wall runs for about 5 kilometers. Two competing
      progenitor theories include hardened sand dunes and once-molten
      rock that seeped through surface cracks and cooled. Dubbed "Inca City"
      for their resemblance to stone walls of an ancient Earth
      civilization, the new Mars Global Surveyor images now show them to
      be part of a larger circular pattern, indicating an origin possibly
      related to the impact crater. (Non-natural origin hypotheses are
      not invoked by conservative scientists unless clear indications exist
      that natural processes could not work.)

      --[View pictures at above URL]-----

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