From: russell.crook@sun.com   
      
   Ian Stirling wrote:   
   > David Cortesi  wrote:   
      
   >>In article <04Ojc.12892$eZ5.7904@newsread1.news.pas.earthlink.net>,   
   >>"Carey Sublette"  wrote:   
      
   >>>...an interstellar probe is...performing a very high speed fly-by...   
   >>>A unique observation mode that only a probe could carry out is having a   
   >>>chunk of probe hit the planet's atmosphere and collect data...   
      
   >>This seems a very careless and possibly disastrous plan.   
   >>What would be the ground effect of an object moving at   
   >>an appreciable fraction of C, grazing the atmosphere of Earth?   
      
   > Oooh, a meteor!   
   > As long as it's small, there isn't much problem.   
      
   Only if "small" means "under a gram".   
   At "an appreciable fraction of C", the   
   kinetic energy of the probe would be equivalent to   
   a noticeable fraction of its rest mass energy.   
   Even at .1c, this is about 1/2 of one percent   
   rest mass equivalent. At this speed, a 1 kg probe   
   would have the energy equivalent of some tens   
   of kilotons of TNT...   
      
   Russell   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)