From: tjroberts137@sbcglobal.net   
      
   On 3/20/22 5:44 AM, Mike Fontenot wrote:   
   > On 3/19/22 12:27 PM, Tom Roberts wrote:   
   >> Observation implies a physical quantity is being observed.   
   >> Simultaneity at different spatial points is not any kind of   
   >> physical quantity, it is a CONVENTION based on the time coordinate   
   >> of a particular inertial frame   
   >   
   > Tom, what is your "take" on the use of an array of clocks,   
   > stationary in some inertial frame, that have been synchronized using   
   > only the assumption that the speed of light is equal to the universal   
   > constant "c" in that frame.  Each of those clocks is attended by a   
   > human "helper friend" (HF), who can observe his immediate local   
   > surroundings.  Another particular observer (whom I'll refer to as   
   > "he"), also stationary in that inertial frame, wants to know (when   
   > his watch shows time tau) the current reading on a particular   
   > distant clock which is NOT stationary with respect to that array of   
   > clocks. It seems reasonable that he is entitled to say that the   
   > current reading on that distant clock is what the HF, who happens to   
   > be colocated with that distant clock at the instant when the HF's   
   > clock reads tau, directly observes it to be.   
      
   Sure, one could do that. Though there seems to be little motivation to   
   do so.   
      
   The particular observer NEVER knows "the current reading" of that   
   distant clock (for any meaning of "current"), he can only learn what it   
   was at some time in the past (e.g. at time tau), after the HF transmits   
   their result to him. Note that in your scenario the particular observer   
   must transmit the value of tau to all HFs well in advance;   
   alternatively, each HF could record values whenever the distant clock   
   passes by, and they all send those records to the particular observer,   
   who can then pick and choose among them, after the fact.   
      
   > Doesn't that convey a sense of "meaningfulness", to the observers who   
   > are stationary in that frame?  I think Einstein thought it does.   
      
   You simply implemented the CONVENTION of Einstein synchronization. If   
   you synchronized the clocks differently you would get a different   
   result. It says nothing at all about other frames.   
      
   Tom Roberts   
      
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