From: tjroberts137@sbcglobal.net   
      
   On 8/9/17 12:55 AM, John Heath wrote:   
   > The SR effects - GR say the traveling west bound twin's clock was   
   > running faster not slower.   
      
   Actually neither clock runs faster, and neither clock runs slower   
   -- ALL clocks run at their usual rate, regardless of how they might   
   move or where they might be located. But when measured in an inertial   
   frame relative to which a clock is moving, it is OBSERVED to run   
   slower than identical clocks at rest in the inertial frame.   
      
   IOW: "time dilation" does NOT affect the clock itself, it is a   
   geometrical projection of the interval between a moving clock's   
   ticks onto the inertial frame used for the measurement.   
      
   > It would make sense if there was a preferred FoR.   
      
   There is no "preferred frame" in the usual sense of it being somehow   
   "special" in the dynamics. But HUMANS who make calculations definitely   
   prefer to use an inertial frame, as calculations are simpler in   
   such coordinates than in non-inertial coordinates. Such human   
   preference, of course, is irrelevant to nature.   
      
   Tom Roberts   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)