From: nicolaas.vroom@pandora.be   
      
   On Friday, 8 September 2017 21:36:23 UTC+2, Phillip Helbig (undress to reply)   
   wrote:   
   > In article <45120854-8647-4c78-99a5-5c2b0839a0eb@googlegroups.com>,   
   > Nicolaas Vroom  writes:   
   >   
   > > The LHC ring has a length of 27 km. Suppose I build a track within   
   > > that ring and on the track I place 270 trains of each 100 meter. etc   
   >   
   > Here's a different spin (pun intended) on this:   
   >   
   > Instead of 270 trains, place 135 trains on the track, spaced   
   > equidistantly.  In other words, pairs of trains are separated by a space   
   > equal to the length of a train.  Same argument as above, but don't   
   > regard the trains---regard the spaces.  Shouldn't they also contract?   
   > If not why not?   
      
   I understand this experiment. My understanding is when the trains   
   contract than the space in between expands. Expands ofcourse is the   
   wrong wording. It is the distance between the train that becomes larger.   
   This increase is a physical consequence of the state (length) of the   
   train, but not of the space inbetween.   
      
   > No serious person claims that "length contraction" is some physical   
   > effect with regard to the material of the object or whatever.   
      
   But what is then the reason to study rigid versus non-rigid objects.   
   Such a distinction only make sense if their is a physical distinction   
   between the two materials in the sense that: A moving rigid object does   
   not show physical "length contraction"; a moving no-rigid object shows   
   physical "length contraction"   
      
   > This   
   > should be obvious from the fact that it depends only on the frame of   
   > reference.   
      
   When you study (perform an experiment) the length of a moving train   
   (rod) from the view point of a frame at rest versus from a moving frame   
   and the first shows no length contraction and the second does etc than   
   you should only use a frame at rest.   
      
   I have a problem to study any physical process using different reference   
   frames because such a frame has nothing to do with the process it self.   
   In fact you should study the total process from the simplest coordinate   
   system because that will give the simplest laws (equations) to describe   
   the process.   
      
   > Thus, it shouldn't make any difference whether I use the   
   > front and back of a train as a fiducial length, or the front and back of   
   > a gap between trains.   
      
   This is only true when there is no length contraction of the train.   
      
   [Moderator's note: Make sure that you don't assume that that which you   
   are trying to prove is true. -P.H.]   
      
   Nicolaas Vroom   
      
   --- SoupGate-Win32 v1.05   
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