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Path: ...!weretis.net!feeder9.news.weretis.net!i2pn.org!i2pn2.org!.POSTED!not-for-mail From: hitlong@yahoo.com (gharnagel) Newsgroups: sci.physics.relativity Subject: Re: Sync two clocks Date: Mon, 19 Aug 2024 23:33:07 +0000 Organization: novaBBS Message-ID: <ad1be0767d67933777b11e63154fbbaa@www.novabbs.com> References: <u18wy1Hl3tOo1DpOF6WVSF0s-08@jntp> <v9nant$1d2us$1@dont-email.me> <vPP1Z1BJfE1Dt7SYhCzEo7ZQWFI@jntp> <va0a4f$30p95$1@dont-email.me> <Zwwc8OsxqpAwTzvPkie6NmgxmY8@jntp> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Injection-Info: i2pn2.org; logging-data="3170081"; mail-complaints-to="usenet@i2pn2.org"; posting-account="p+/k+WRPC4XqxRx3JUZcWF5fRnK/u/hzv6aL21GRPZM"; User-Agent: Rocksolid Light X-Rslight-Posting-User: 47dad9ee83da8658a9a980eb24d2d25075d9b155 X-Rslight-Site: $2y$10$TVP/XVW0CfNyizdV2dgZTu1B7iVXufTS9NQ101MBXK9/hms1P6/gG X-Spam-Checker-Version: SpamAssassin 4.0.0 Bytes: 5136 Lines: 109 On Mon, 19 Aug 2024 23:15:28 +0000, Richard Hachel wrote: > > Le 19/08/2024 à 22:32, "Paul.B.Andersen" a écrit : > > > > Below I show how two real clocks in the real world can be > > synchronised, strictly according to Einstein's method. > > > > We have to equal clocks C_A and C_B. They are not synced in any way, > > but they are using the same time unit, let's call it second. > > The clocks run at the same rate. > > > > In our very big, inertial lab, we have two points A and B which are > > separated by some distance. Let's call the transit time for light > > to go from A to B is x seconds. We will _define_ that the transit time > > is the same from B to A. (This follows from Einstein's definition > > of simultaneity). > > > > At point A we have: > > Clock C_A, a light-detector, a flash-light and a computer. > > The computer can register the time shown by C_A when > > the flash-light is flashing, and when the light-detector > > registers a light-flash. > > > > At point B we have: > > Clock C_B, a light-detector, a mirror and a computer. > > The computer can register the time shown by C_B when > > the light-detector registers a light-flash. > > > > In the following we will synchronise clock C_B to clock C_A. > > That is, we will adjust clock C_B so it become synchronous > > with clock C_A. > > > > Now we let the flash-light at point A flash. > > At this instant, C_A is showing tA = n seconds. > > tA is measured by C_A at A. > > > > When the flash hits the light-detector at B, > > Clock C_B shows tB = m seconds. > > tB is measured by C_B at B. > > > > A short time later the light detector at A registers > > the light reflected by the mirror at B. > > At this instant Clock C_A shows t'A = n + 2x seconds. > > t'A is measured by C_A at A. > > > > Einstein: > > "The two clocks synchronise if tB − tA = t'A − tB." > > > > Or: tB = (tA + t'A)/2 = (n+n+2x)/2 = (n + x) > > > > That is, to be synchronous clock C_B must show a time midway > > between tA and t'A when the light is reflected by the mirror. > > So tB should show (n + x) seconds when the light is reflected > > by the mirror. > > But at that instant tB is showing m seconds, so to make the two > > clocks synchronous, we must adjust clock C_B by: > > δ = (n-m) + x seconds. > > > > > > After this correction, we have: > > > > tB − tA = (m - n) seconds + δ = x seconds > > t'A − tB = (n + 2x - m) seconds - δ = x seconds > > > > The clocks are now synchronised. > > > > Please explain what in the above you find impossible > > to do in your lab. > > I have explained these things a hundred times. And your explanation has been refuted millions of times :-)) > It is impossible to synchronize two watches A and B located > in different places. “There is no point in using the word 'impossible' to describe something that has clearly happened.” – Douglas Adams > It is not a technical problem, it is not a problem of > intelligence, it is simply that it is as impossible as finding a round square, or a natural number between 5 > and 6. Because nature is not made like that. “There is no point in using the word 'impossible' to describe something that has clearly happened.” – Douglas Adams > Anyone who wants to synchronize watches with each other does > not realize that he is looking for rabbit horns. https://allthatsinteresting.com/jackalope > The only thing we can do is to find a kind of abstract, > imaginary synchronization procedure, called the Einstein > procedure where tAB is supposed to be equal to tBA How can tAB not be equal to tBA for light is vacuum? > not only for the point M which is the only real origin of > the synchronization, but for everyone. If tAB = tBA, then Paul's procedure works. If tAB <> tBA, then your point M method won't work either. > We then have a useful procedure, but false. I set my watch to my wall clock months ago and it's still in sync. You're spouting baloney, Richard. > [Rest of misinformed baloney deleted]