From: nicolaas.vroom@pandora.be   
      
   On Friday, 13 October 2017 01:24:07 UTC+2, Nicolaas Vroom  wrote:   
   >   
   > [[Mod. note -- Analysing the "Vroom synchronization" process in a   
   > moving reference frame isn't as simple as "In a moving frame all   
   > these clocks will run slower":   
   > * You need to look at how both space *and* time coordinates   
   >   transform as measured by moving observers.   
      
   Why do we need moving observers.   
   The first step is to define a clock at rest which consists of 6   
   mirrors (light can also go through these mirrors.   
   The characteristic of this clock is when a light signal is send   
   towards each mirror the reflection will real the origin simultaneous   
   meaning that the clock ticks simultaneous in all three directions.   
   The second step is to use this clock to synchronize all clocks   
   in a latticework.   
   There is a problem if even these clocks at rest are influenced by   
   gravity.   
   Using this latticework you can study the behaviour of one moving clock   
   which is identical as each of the clocks in the latticework.   
   What tests will reveal that such a moving clock will run slower   
   compared with the clocks in the latticework.   
   However it is even slightly more complicated. If you study a moving   
   clock in the x direction its ticking in the x direction will run slower,   
   but also its ticking in the y direction will be affected (differently).   
   The same for the z direction.   
      
   > * You defined Vroom synchronization to use (only) light signals   
   >   moving in the three orthogonal coordinate directions.  But a   
   >   light signal which the stationary observers measure to be moving   
   >   in (say) the +y direction (i.e., to have time-independent x and z   
   >   coordinates), will be measured by the moving observers to NOT   
   >   be moving in the in the +y direction -- its x coordinate will   
   >   clearly be time-dependent.   
   See above.   
      
   > Assuming that we're in flat (Minkowski) spacetime, if you use   
   > Einstein's special relativity then you can study the laws of nature   
   > in any reference frame you want   
   > 	[though things are usually a lot simpler if   
   > 	you choose an inertial reference frame]   
   > and you'll still get consistent results.   
      
   Why can not (?) I study the laws of nature i.e. the movement of the   
   planets (a galaxy) in one reference (large) frame which I consider at rest?   
      
   Why do I need one inertial frame? IMO you can not define one inertial   
   frame you always need at least two reference frames? Or am I wrong?   
      
   > If you use some other (non-Einstein) relativity theory, well, your   
   > results will depend on what theory you use.   
   > -- jt]]   
      
   Nicolaas Vroom   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)