From: helbig@asclothestro.multivax.de   
      
   In article ,   
   Richard Livingston  writes:   
      
   > > That's all true. But I am not interested in what TV images he receives   
   > > from her ... those just tell him what she looked like in the past, and   
   > > how old she was in the past. Instead, I am interested in what he   
   > > DEDUCES about her CURRENT age at any given instant in his life, using   
   > > the laws of special relativity. I.e., I'm interested in his "NOW"   
   > > instant ... what does he say her age is "RIGHT NOW", at some instant in   
   > > his life. I'm purely interested in what he says about "simultaneity at   
   > > a distance".   
   >   
   > Simultaneity at a distance is not observable.   
      
   In his most recent book*, Carlo Rovelli summarizes it like this:   
   Galilean relativity expresses the idea that the concept of being in the   
   same place at different times is ill-defined (relative to what?), while   
   Special Relativity expresses the idea that the concept of happening at   
   the same time in different places is equally ill-defined.   
      
   Does anyone disagree?   
      
   Considering that one recovers non-relativistic physics in the limit that   
   the speed of light goes to infinity, is it fair to say that the finite   
   speed of light is the SOLE reason for differences between   
   non-relativistic and relativistic physics?   
      
   __   
   * _General Relativity: The Essentials_, by Carlo Rovelli (Cambridge   
   University Press), 2021.  Pp. 180, 23 =D7 15.5 cm.  Price =A314.99   
   (paperback, ISBN 978 1 00 9013697).   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)