Re: [SR and synchronization] Cognitive Dissonances and Mental Blockage

Le 18/08/2024 à 11:57, Thomas Heger a écrit :

Am Samstag000017, 17.08.2024 um 14:52 schrieb Python:

**An Interesting Case of Mental Blockage and Cognitive Dissonance:**
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*Einstein-Poincaré Synchronization Procedure and Dr. Lengrand*
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What’s fascinating about certain cranks is that just when you think you’ve seen all the absurdities they can come up with, they manage to produce something even worse. Their cognitive dissonance and ability to pull out bizarre notions from who knows where, on top of a perfectly well-defined technical procedure, is astonishing. We’ve seen this before with GPS, where Hachel invents all sorts of fantasies, like atomic clocks in the receivers or synchronization with a clock infinitely far away in a fourth spatial dimension...
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This is a report of exchanges on the synchronization procedure described by Einstein in his 1905 paper, discussions that took place 17 years ago and more recently on sci.physics.relativity and fr.sci.physique.
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https://groups.google.com/g/fr.sci.physique/c/KgqI9gqTkR8/m/oMc9X0XjCWMJ
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*Reminders on the Procedure:*
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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.
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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.
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*Steps of Einstein's Method:*
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When clock A shows t_A, a light signal is emitted from A towards B.
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When this signal is received at B, clock B shows t_B, and a light signal is sent from B back towards A.
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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.

But this requirement was not fullfilled in Einstein's scheme, because Einstein didn't take delay into consideration.

The delay *is taken into account* this why (AB)/c intervene, as I've
shown.

If A and B are located at different places in the universe and maintain their distance (at least as long as the procedure lasts), then delay (A->B) should be equal to delay(B->A).
 If you would encode time into the exchanged signal, you could compare the local reading of your own clock (at -say- B in this case) with the content of the code in the received message from A, if you add delay(A->B) to t_A (which is encoded in the timing signal).

What you wrote is a fantasy of yours and has nothing to do with
Einstein's procedure which embed the delay in the two postulates
he stated (one is backed by experiments about round trip light
propagation, the other one is - partly - conventional).

But Einstein didn't calculate that delay, nor even mentioned it.

Every sane person recognize the delay when noticing that (AB)/c is
appearing when you turn the verification procedure into a
synchronization procedure. You are NOT a sane person, you are
a demented crook.

So Einstein assumed something absurd:

No. You do.

beings at B should see a blink of light, comming from A, compare that with their own clock and sent a light signal back to A.
 But: how do these beings know t_A in the first place?

Easy: juste write down t_A on a piece of paper when emitting the
first signal.

Sure, Einstein assumed kind of 'large telescope setting', where beings at B could see the clock at A.

Not at all. There is nothing of this kind in Einstein's procedure. This
is something you made up.

But this wouldn't cause a symmetric synchronization, because the signal arrives delayed at B and Einstein didn't calculate that delay.

The delay is embedded in the procedure. What do you think (AB)/c is?

This would cause an obvious error, because the clock at B had to be set to an earlier time setting than it should, because the vision of the remote clock is delayed.

And the delay is taken into account.

Now this cannot be made symmetric, because otherwise the beings at both ends of the communication would turn their own clocks earlier and earlier (with each communication), because the remote station does that, too.

It is symmetric. The proof is actually quite easy, even if out of your
reach.