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Failed to connect to MySQL: (1203) User howardkn already has more than 'max_user_connections' active connectionsPath: ...!news.mixmin.net!eternal-september.org!feeder3.eternal-september.org!news.eternal-september.org!.POSTED!not-for-mail From: Mikko Newsgroups: sci.physics.relativity Subject: Re: [SR and synchronization] Cognitive Dissonances and Mental Blockage Date: Tue, 20 Aug 2024 14:00:41 +0300 Organization: - Lines: 65 Message-ID: References: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Injection-Date: Tue, 20 Aug 2024 13:00:41 +0200 (CEST) Injection-Info: dont-email.me; posting-host="c68d48608550e7e7fabcc3f8200ba7d3"; logging-data="3536257"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX1/L5etW0oI9F7EowYxQBQXU" User-Agent: Unison/2.2 Cancel-Lock: sha1:nIC2qmNXK4tCQXuO9HI4nIsyOGU= Bytes: 3752 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