From: arc5@ix.netcom.com   
      
   Jeffrey Cornish wrote:   
      
   > As metorite impacts are random events, and the debris from such impacts   
   > would likely be randomly sized, please explain the uniform size and   
   > distribution of the blueberries.   
      
   Uniform distribution:   
   We cannot really say this; the rovers have covered   
   a vanishingly small fraction of the surface.   
   Even if we do see blueberries over a wide area-   
   the Martian atmosphere is not as dynamic as the Earth's and   
   would have a similar effect on wet, fine-grained matter   
   over a larger area.   
   Given the consistent texture of the fine-grained component   
   of impact ejecta on the Martian surface,   
   consistent upper atmosphere dynamics over a large part of the planet   
   and also given a surface covered either with a shallow brine sea   
   or with saturated mud flats (the current model), the ejecta   
   from large impacts would behave in a consistent manner.   
      
   The blueberries we see are uniform in size for several reasons:   
   The wet, pulverized particles ejected into the upper atmosphere would   
   be "sorted" (larger particles falling out at lower altitudes), sending   
   very fine-grain and water saturated material into the cold, windy   
   Martian "stratosphere."  As with Earthly hailstones, the energy of   
   the fine-grain mud's motion, transferred into rotation as the particles   
   froze and accumulated, acquire a rounded shape as their "spin"   
   precludes further accumulation, the size of the spheres being   
   dependent on many factors but mostly on these atmospheric effects,   
   which we already know to be more uniform over a larger area than in   
   an Earthly "thunderstorm."  Earth storms generate hailstones   
   of uniform size in this manner,   
   their sphericial size dependent on the storm's dynamics over   
   the area it covers.  Since Martian atmospheric dynamics are   
   still energetic but simpler, the similar-sized "mud hail" result   
   would cover a much wider area with a consistent hailstone size.   
   Lower gravity, lower atmospheric pressure, etc.- all contribute   
   to a more uniform process over a larger area.   
      
   And it's still just "one man's opinion;"   
   I'm not smart enough to deal in hypothesis ;-).   
   What would disprove it?   
   Several things could-   
   the first being general disuniformity in   
   the internal structures or large-particle inclusions   
   ( in the few we've seen "ground open,"   
   the structure has been fine and uniform, such as you would expect   
   from the process I've posited).   
   A closer study of the fine grain that supported slow accumulation   
   as in the current "concretion" hypothesis would disprove it.   
   Frankly, I think the lack of large inclusions stands against   
   the "concretion" answer, along with other questions.   
   I'm sure there are others- I guess we'll have to wait   
   until someone actually has some blueberries to study.   
   Don't hold your breath ;-).   
      
   Kindly,   
   David S.   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)