From: fortunati.luigi@gmail.com   
      
   wugi il 05/09/2023 09:21:30 ha scritto:   
   > ...   
   Richard Livingston il 05/09/2023 06:01:20 ha scritto:   
   > ...   
      
   We obviously live in different worlds.   
      
   In my world, a body that contracts, compresses.   
      
   And a rigid body doesn't become flexible just because it's in motion.   
      
   [[Mod. note --   
   You are taking it for granted that the body does in fact contract   
   or become flexible.  But those observations are made by an observer   
   who is not at rest with respect to the body!   
      
   If observer A (at rest with body X) observes X to be uncontracted,   
   and observer B1 (moving at velocity v1 with respect to X) observes X   
   to be contracted by some amount R1, and observer B2 (moving at some   
   different velocity v2 with respect to X) observes X to be contracted   
   by some different amount R2, what should we infer?  More generally,   
   there are infinitely many possible observers B1, B2, B3, B4, ...,   
   each of who will observe a different contraction of X.   
      
   In special relativity, the answer is that we privilege observations   
   made in the rest frame of the body being observed (in this case X).   
      
   To put it another way, can you explain why you think it's paradoxical   
   that observer B1 observes something different from observer A?   
   -- jt]]   
      
   --- SoupGate-Win32 v1.05   
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