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From: Mikko <mikko.levanto@iki.fi>
Newsgroups: sci.physics.relativity
Subject: Re: [SR and synchronization] Cognitive Dissonances and Mental Blockage
Date: Tue, 20 Aug 2024 14:00:41 +0300
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On 2024-08-20 06:02:49 +0000, Thomas Heger said:

> Am Montag000019, 19.08.2024 um 14:56 schrieb Python:
>> Le 19/08/2024 à 08:44, Thomas Heger a écrit :
>>> Am Sonntag000018, 18.08.2024 um 12:05 schrieb Python:
>>> 
>>>>>> Two identical clocks, A and B, are stationary relative to each other at 
>>>>>> a certain distance. Their identical functioning (within measurement 
>>>>>> accuracy) allows us to assume that they "tick at the same rate." 
>>>>>> NOTHING more is assumed, especially regarding the time they display; 
>>>>>> the purpose is PRECISELY to adjust one of these clocks by applying a 
>>>>>> correction after a calculation involving the values indicated on these 
>>>>>> clocks during specific events, events that occur AT THE LOCATION OF 
>>>>>> EACH CLOCK.
>>>>>> 
>>>>>> Einstein’s procedure is not strictly a synchronization procedure but a 
>>>>>> method to VERIFY their synchronization. This is the main difference 
>>>>>> from Poincaré’s approach. However, it can be proven that Poincaré’s 
>>>>>> method leads to clocks synchronized in Einstein’s sense. You can also 
>>>>>> transform Einstein’s verification method into a synchronization 
>>>>>> procedure because it allows calculating the correction to apply to 
>>>>>> clock A.
>>>>>> 
>>>>>> *Steps of Einstein's Method:*
>>>>>> 
>>>>>> When clock A shows t_A, a light signal is emitted from A towards B.
>>>>>> 
>>>>>> When this signal is received at B, clock B shows t_B, and a light 
>>>>>> signal is sent from B back towards A.
>>>>>> 
>>>>>> When the signal is received at A, clock A shows t'_A.
>>>>> 
>>> 
>>>>> Relativity requires mutally symmetric methods. So if you synchronize 
>>>>> clock B with clock A, this must come to the same result, as if you 
>>>>> would synchronize clock A with clock B.
>>>> 
>>>> It is.
>>> 
>>> No, it is not!
>> 
>> It is. It is explained in my initial post : What is (AB)/c to you?
> 
> AB was actually meant as:

Note that in Einstein's text the definition of synchronity (page 894)
does not use AB. Lower on the same page AB has an overbar.

> distance from A to B,
> 
> even if A and B are in fact position vectors, hence AB would usually be 
> the scalar product of A and B (what is absurd).

A nad B are not position vectors, they are positions. Postions are not
vectors. AB with overbar is the standard notation for the distance btween
positions A and B.

> Besides of this little formal issue (actually meant was |r_AB| ), 
> Einstein had not written AB/c (or r_AB/c).

Einstain also used r_AB, whith an explicit definition of its meaning.

-- 
Mikko