From: sylvia@email.invalid   
      
   On 20/06/2019 1:56 am, PengKuan Em wrote:   
   > Le mercredi 19 juin 2019 08:39:04 UTC+2, mfreem...@gmail.com   
   > a =C3=A9crit=C2=A0:   
   >> What does it even mean to measure the length of a moving body? Other   
   >> than noting the time and position of the ends, which involves time   
   >> dilation, how do you do it?   
   >   
   > In books like <>   
   > by Steve Adams or <> by James   
   > H. Smith, they explain how length contraction works. It is in that   
   > manner that I think that length of object should be measured.   
   >   
   > In the frame of the object, the length is at rest and measured. In   
   > the frame where it is moving, its both ends are noted at the same   
   > time.   
   >   
      
   So now you have to synchronise spatially separated clocks, and to do   
   that you have to must assumptions about space time. The obvious   
   assumption is that special relativity is correct, and that you can use a   
   method that synchronises clocks in special relativity.   
      
   But now you are no longer just testing length contraction. Instead, you   
   are looking at whether the entire experimental situation gives results   
   that are consistent with relativity.   
      
   Sylvia.   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)