From: henry@spsystems.net   
      
   In article ,   
   Rodney Kelp  wrote:   
   >Every time I see photos of mars there are rocks strewn all over the place as   
   >if there were lots of large explosions in relatively recent past. The rocks   
   >still have sharp square edges rather than being rounded by plenty wind and   
   >sand storms. Almost like a war of global proportions would produce.   
      
   Meteorite impacts are effectively explosions.  For anything sizable, the   
   arrival velocity is so high that the first contact vaporizes part of the   
   meteorite and part of what it hits, and the resulting explosion blows the   
   remainder of both apart.  And indeed, if you look at those photos, you'll   
   also see that impact craters -- large and small -- are everywhere.   
      
   Erosion from windblown dust is much slower than you might think, bearing   
   in mind that Mars's atmosphere is extremely thin.  Mars has *dust* storms,   
   not *sand* storms, and it's the larger particles that you need for serious   
   erosion.  Those fresh-looking rocks may have been there a long time.   
   --   
   "Think outside the box -- the box isn't our friend."    |   Henry Spencer   
                                   -- George Herbert       | henry@spsystems.net   
      
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