From: nicolaas.vroom@pandora.be   
      
   On Monday, 9 July 2018 21:11:48 UTC+2, Tom Roberts  wrote:   
   > On 7/6/18 9:34 AM, Nicolaas Vroom wrote:   
   > > The comparison is done at two specific moments. First at moment t1   
   > > when the two clocks depart at P1. Secondly at moment t2 when the two   
   > > clocks arrive at P2.   
   >   
   > OK. That is clearly a comparison of total elapsed proper times for the   
   > two clocks. That is most definitely NOT a comparison of their tick rates.   
   >   
   > Heed the dictum: do not attempt to discuss quantities that you did not   
   > measure.   
      
   Let me describe the strategy I want to follow:   
   The bassic strategy is to use a 3D grid (exactly the same as described   
   in the book 'SpaceTime Physics' i.e. a latticework).   
   At all the grid points you place a clock (based on parallel mirrors).   
   One clock you call a Reference Clock. With that clock you can synchronise   
   all the other clock.   
   The next step is to count the number of ticks for one day. (I will not   
   go into the details of how to define a day). Next you divide this   
   total count by 24*60*60 and you get the number of ticks per second.   
      
   Using this 3D grid or latticework you can follow the evolution of   
   the two clocks when they travel both from P1 to P2 along different path's   
   or when one clock stays at P1 and the other clock moves from P1 to P2   
   and back to P1.   
   With 'follow the evolution' I mean compare total results (ticks and   
   avg rates) from start to finish or intermediate results.   
      
   > As I have said before: If you want to directly compare two clocks' tick   
   > rates, you physically cannot do that if they are not co-located and   
   > co-moving -- anything else requires signals, and you must unwind the   
   > effects of the signals (Doppler shifts); do that and you find that   
   > identical clocks always tick at identical rates.   
      
   I hope that the use of this latice work solves this issue.   
   IMO you can also do the same by replacing the clocks (with parallel   
   mirrors) in the grid with atomic clocks. The moving clock from P1 to   
   P2 still use parallel mirrors.   
      
   > > It is the physics (inner workings) of a clock that describes its   
   > > beheviour.   
   >   
   > OK. In SR and GR, the local laws of physics are the same in any locally   
   > inertial frame #1. Since clock tick rates are determined #2 by such laws,   
   > clocks ALWAYS tick at their usual rate #3; this is so regardless of how   
   > they might move or where they might be located.   
      
   Sorry to say but laws or models are descriptions of the physical reality.   
   The laws don't determine how the universe evolves. It is the other way   
   around. At the start of human evolution there are no laws (as known by   
   humans). Laws evolved because humans for example used tools.   
   Friction to make fire. A hourglass to measure time (expressed in counts).   
   Newton's law is also the result of a long evolution. The same for SR and GR.   
   That does not mean that these two laws cannot have the same fundamentals.   
      
   #1 To understand that, we must know what the laws of physics are.   
   IMO identical processes have identical descriptions (laws).   
   This is true for the whole universe.   
   #2 The usage of the word 'determined' is wrong.   
   Accordingly to Webster Determinism b: the theory that all occurences   
   in nature are determined by antecedent causes or take place in   
   accordance with natural laws - called also cosmological determinism.   
   #3 (Identical) clocks at identical situations tick at the same rate.   
   Under different situations the tick rate can be different.   
   For example as a function of a gravitational field.   
      
   > Bottom line: This whole brouhaha is caused by your insistence on   
   > discussing tick rates, when they are not measured. DON'T DO THAT.   
   > Discuss what is actually measured and you won't go wrong.   
      
   I'm fully agree with the importance to discus measured parameters.   
   As such I don't understand why people declare the speed of photons   
   constant why it is easy possible that this speed can be a function   
   of external conditions.   
      
   > Tom Roberts   
      
   Nicolaas Vroom   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)