From: nicolaas.vroom@pandora.be   
      
   On Tuesday, 16 July 2019 23:10:23 UTC+2, Tom Roberts  wrote:   
   > On 7/14/19 7:56 PM, Nicolaas Vroom wrote:   
   > > IMO the most important question to answer is: what is the physical   
   > > explanation of length contraction.   
   >   
   > This is really geometrical: both "length contraction" [#] and "time   
   > dilation" [#] are simple geometrical projections. No physical properties   
   > of anything are changed, but when you measure such properties from   
   > frames relative to which an object is moving, you get values different   
   > from when it is at rest.   
      
   Personally I prefer the method described by JT in which in principle you   
   use one (inertial) reference frame and describe (measure) the complete   
   state of the universe simultaneous.   
      
   > 	Think about it: it must be possible for multiple observers >   
   	in multiple frames to observe a given object, and they all >   
   	get different values.   
      
   I agree with you when a rod is considered because in all these   
   measurements different physical time delays are involved, caused by the   
   light travel time of the photons along different path length. However   
   and that is important: these physical measurements don't cause any   
   physical change within the rod. The length does not physical change.   
      
   >       Geometrical projections do just that,   
   > 	but ask yourself how any "physical change" of the object   
   > 	could do it....   
      
   But geometrical projections is mathematics ......   
      
   The problem is time dilation of moving clocks. If you want to know the   
   time of moving clock which moves away from you, you get a time count   
   that is always earlier than the actual time at the moment when you   
   receive that information. The reason is simple communication time   
   between sending and receiving any message (which is a function of   
   distance) Sending and receiving does not cause any physical effect on   
   the clocks in use.   
      
   What causes a physical effect is the internal operation of a clock if   
   you compare a moving clock versus a clock at rest. The moving clock runs   
   physical slower compared to a clock at rest. Depending about the   
   internal operation of the clocks the mathematics which describe this   
   physical behaviour are the Lorentz Transformations   
      
   Nicolaas Vroom   
      
   --- SoupGate-Win32 v1.05   
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