Re: Relativistic synchronisation method

Le 17/12/2024 à 14:49, "Paul.B.Andersen" a écrit :

stationary ones).

 Your wristwatch and my wristwatch are both showing UTC + 1 hour.
 To synchronise my wristwatch, I used this:  https://time.is/clock
 How did you synchronise your wristwatch to show UTC + 1 hour, Richard?
  You will ignore this, but I will ask you again.

Paul, Paul, I beg you to understand something.
There is no absolute simultaneity. To say that two events occurred at the same time only makes sense locally and for ONE given observer.
An observer placed in another location will not have the same notion of what is simultaneous or not, and various events that are placed in a given hyperplane of simultaneity (the set of events that occur in the local present time of an individual), will no longer be in a hyperplane of present time for another individual.
Each hyperplane can only be unique.
Thus, I could never synchronize your watch with mine in absolute terms, and for example five or ten simultaneous events for me (in the same hyperplane if I draw a 3D diagram) will necessarily no longer be simultaneous for you, and vice versa.
It is therefore necessary to synchronize on something abstract, and to refer to what this watch NOTES of the various events. This watch, I call it watch M, it is the abstract, virtual watch that all physicists adopt without knowing that it is the one they are adopting.
It is the one that gives "a certain coherence", and gives "usable labels" to things.
But two watches, in themselves are incongruous without going through this. A fortiori billions of watches placed in our universe (even stationary ones).
All are set to this virtual watch M, which is used to consider that there is a "flat" present, and therefore that we can synchronize things.
But it is abstract, OUTSIDE-WORLD.
Useful, yes. Very useful. But outside-world.
I beg you (vain hope) to understand this before criticizing something that you have not previously understood.
R.H.