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From: "Paul.B.Andersen" <relativity@paulba.no>
Newsgroups: sci.physics.relativity
Subject: Re: Sync two clocks
Date: Thu, 22 Aug 2024 20:20:08 +0200
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Den 22.08.2024 13:09, skrev Richard Hachel:
> When I talk about type M (or Einstein type) synchronization, 
> I am talking about the need to represent a coherent universal
> simultaneity for the entire terrestrial frame of reference.
> 
> However, this absolute and universal simultaneity, even 
> in a simple, simple inertial reference frame, cannot be used, 
> because it DOES NOT EXIST.

Quite right. It is no absolute and universal simultaneity.

Since you still seem to think that it was Richard Hachel
who  discovered this, it is obvious that you do not read
what I and others write to you.

Den 22.08.2024 Paul B. Andersen wrote:
|
| And you believe it is YOU that have discovered that? 😂
|
| Before 1905 everybody believed it was a "universal, present now",
| that simultaneity was absolute, and that clocks could be
| absolutely synchronised. Newton took it for granted!
|
| But Einstein showed that there is no absolute simultaneity,
| and clocks can't be absolutely synchronised.
|
| https://paulba.no/paper/Electrodynamics.pdf
| See: § 1. Definition of Simultaneity
|
| Did you really not know that it was Einstein who discovered this? 😂


> 
> We must therefore find a "neutral" point, for which a certain 
> form of simultaneity would exist, but all the points of 
> the universe would have to be at an equal distance from it, 
> in order to synchronize all the watches, on its notion of proper 
> present .
> We must therefore imagine a point ideally placed very far away, 
> in an imaginary fourth dimension, and imagine that it is this 
> which simultaneously gives the start to all the watches in 
> the universe.

This is nonsensical that only a mentally disturbed person
could have written it!


> 
> This is what Einstein synchronization does if you look closely, 
> and this is why it is mathematically coherent and easily usable.

So if we look closely in Richards disturbed mind, Einstein
synchronised his clocks from a far away point in an imaginary
forth dimension. :-D

There is no _absolute_ simultaneity, but Einstein _defined_
what he meant by simultaneity _in an inertial frame_.
And with this _definition_, we can make two clocks at different
locations in the inertial frame simultaneously show the same;
the clocks are synchronous _in said frame of reference_.
But they are NOT synchronous in a frame of reference which
is moving relative to the first frame of reference.

Note that clocks showing UTC are synchronous in the non-rotating
Earth centred frame of reference (ECI-frame), but they are NOT
synchronous in the ground frame.
Note the rather peculiar phenomenon that the UTC clocks
are synchronous in the frame were they are moving, but
not synchronous in the frame where they are stationary.

Of course "simultaneity" and "synchronism" are man made,
theoretical notions, but they are very practical, and
the world would be even more chaotic than it is without it.
Think if it was no way to tell you when your train or
aeroplane would go, and there was no way to tell you
when you would arrive at the destination. The world
is _very_ dependent on synchronous clocks.

> 
> But that does not mean that two watches A and B marking the same 
> time for M and "existing in perfect simultaneity with M" mark 
> together and reciprocally the same time.
> 
> This is a false and abstract thought from a person who does 
> not understand the basis of the theory of relativity.
> 
> The two watches are actually offset from each other by dt=AB/c
> anisochrony value valid for the entire universe.

There are millions of synchronous clocks (in ECI frame) in
the universe. Are all these clocks offset from each other by dt=AB/c?


> The notion of absolute universal present does not exist, 

Still right. As Einstein demonstrated!

> and it
> is this special synchronization which creates it on what 
> a distant, idealized and “neutral” observer would perceive.

But the distant, idealized and “neutral” observer Richard Hackhel
can still perceive it.

Well done, Richard. Dream on!

-- 
Paul

https://paulba.no/