From: heathjohn2@gmail.com   
      
   On Sunday, June 24, 2018 at 11:12:35 AM UTC-4, Nicolaas Vroom wrote:   
   > On Saturday, 23 June 2018 20:08:43 UTC+2, Tom Roberts  wrote:   
   >   
   >> Not in GR. In GR, the local laws of physics are the same everywhere,   
   >> including the laws that govern the ticking of watches. So the two   
   >> watches tick at the same rate (assuming they are identical).   
   >   
   > The question is what are the laws that govern the ticking of the watches?   
   > In general physical processes depent about certain parameters (T,P,V etc)   
   > and if these parameters change the behaviour of these processes change.   
   > For example: if you place to identical clocks side by side they behave   
   > the same because all the parameters are identical.   
   >   
   >> 	[This also applies to SR, for watches moving differently.   
   >> 	 Note that this English phrasing implies we are discussing   
   >> 	 the watches' intrinsic tick rates, and NOT how someone   
   >> 	 else might observe them.]   
   >   
   > IMO the general assumption should be that the start and end of the   
   > experiment should be the same.   
   >   
   >> Other methods of comparison are possible; all physically realizable ones   
   >> yield the same result, including a very different approach: start with   
   >> them together and synchronized, move them slowly to the tower's top and   
   >> bottom, wait a while, move them slowly back together, and compare their   
   >> displayed times.   
   >   
   > The question: is what is the result of the experiment.   
   >   
   >> All too many elementary books and discussions talk about "clocks ticking   
   >> slower" than other clocks.   
   >   
   > Also here the same question: What was the result of the experiment.   
   > The conclusion can be that the # of ticks on the clocks is different.   
   >   
   >> In GR this is just plain wrong -- all clocks   
   >> tick at their usual rate, no matter where they are located or how they   
   >> might move (relative to anything) [@].   
   >   
   > The issue is if they always tick at their usual rate i.e. constant rate.   
   > To answer that you have to compare the clocks with a standard clock   
   > (Which also uses light signals)   
   >   
   >> Relativity is more subtle, and   
   >> more complicated, than those books and discussions can capture (because   
   >> they make a fundamentally wrong assumption about clock tick rates,   
   >> essentially ignoring the first postulate of SR).   
   >   
   > IMO the most important step is to explain the experiments you perform   
   > accurately and the results of the experiments.   
   > Only after that you can say how GR (or SR) explains the results.   
   > Suppose at the beginning of the experiment at position A the # of counts   
   > of all the clocks is the same (zero) and at the end of the experiment   
   > the # of counts of 'all' the clocks (at position B) is different.   
   > I think there is nothing wrong with that.   
   > I also see no problem if you claim that the average ticking rate of these   
   > clocks is different.   
   > The true question is what is the cause.   
   > If some of the clocks are put in orbit around the Sun and the planets   
   > of course gravity is at stake.   
   > For simpler experiment the average speed of each clock is an issue.   
   >   
   > Nicolaas Vroom.   
      
   Neither A or B is qualified to make this measurement. Only a third party   
   C in the middle of A and B can make this measurement as C can make this   
   measurement with 1 clock , C clock , that can not have a bias that   
   favors A or B as it is 1 clock only for both measurements.   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)