From: fortunati.luigi@gmail.com   
      
   The twins A and C are in station A, twin B is in station B.   
   A-----------------------------B   
      
   The traveling twin C departs from A and travels towards B at a   
   relativistic speed equal to gamma=2.   
      
   During the journey, in front of the twin C passes the clock of an   
   intermediate station.   
      
   The train's camera films that clock for a nanosecond (train time).   
      
   Is it correct to say that on the video of that nanosecond, the station   
   clock advances by HALF nanosecond?   
      
      
   [[Mod. note -- Probably not: you need to take into account the varying   
   light-travel-time from the clock to the train's camera.  It's precisely   
   to avoid this issue that special relativity introduces the concept of   
   a "reference frame" with a (gedanken) infinite set of observers, so   
   all observations can be made by colocated observers who don't suffer   
   from light-travel-time effects.   
   -- jt]]   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)