Groups > sci.physics.relativity > #666375

Re: Universal anisochronism

From	Mikko <mikko.levanto@iki.fi>
Newsgroups	sci.physics.relativity
Subject	Re: Universal anisochronism
Date	2025-09-29 12:43 +0300
Organization	-
Message-ID	<10bdkbg$2tmf8$1@dont-email.me> (permalink)
References	<b7GfLGeT6J4bGflGjf12RMdqpAQ@jntp>

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On 2025-09-28 11:19:34 +0000, Richard Hachel said:

> The problem of synchronization.
> Is it possible to synchronize multiple clocks located in different 
> positions within an inertial frame of reference?

Yes, if the clocks are stationary with respect to that frame and there is
no significant gravity.

> In Newtonian physics, yes, because space and time are considered 
> independent entities.

In a Newtonian world you can synchornize two clocks in the same place,
and they stay syncronized when moved to different places. In the real
world moving them will desynchronize them.

> In relativistic physics, this is no longer possible, since each clock 
> has its own concept of universal simultaneity, specific to its own 
> frame of reference.

By the usual concept of simultaneity is not clock specific, only frame
specific. If you have a coordinate system with a time coordinate then
you can define that clocks showing the coordinate time are synchronous.

> Let's send a signal from point M, the midpoint of AB, to points A and 
> B.  It is clear that for M, regardless of the time at which it assumes 
> the signal was received by the two other points, the two events tA and 
> tB would have been simultaneous. M doesn't know "when" they occurred, 
> but it knows "that they were, by definition, simultaneous FOR IT, since 
> the distances MA and MB are equal."

That requires that the speed of the signals to A and to B have the same
speed.

> However, in relativistic physics, for observer A, the two events are 
> not simultaneous, nor are they for observer B.

They are if simultaneity is defined with those signals.

-- 
Mikko

Thread

Universal anisochronism Richard Hachel <rh@tiscali.fr> - 2025-09-28 11:19 +0000
  Re: Universal anisochronism Harold Babosov <sava@ob.ru> - 2025-09-28 12:56 +0000
    Re: Universal anisochronism Richard Hachel <rh@tiscali.fr> - 2025-09-28 13:12 +0000
      Re: Universal anisochronism The Starmaker <starmaker@ix.netcom.com> - 2025-09-28 16:36 -0700
        Re: Universal anisochronism "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2025-09-28 17:14 -0700
  Re: Universal anisochronism The Starmaker <starmaker@ix.netcom.com> - 2025-09-28 10:23 -0700
    Re: Universal anisochronism The Starmaker <starmaker@ix.netcom.com> - 2025-09-28 10:32 -0700
      Re: Universal anisochronism The Starmaker <starmaker@ix.netcom.com> - 2025-09-29 16:11 -0700
        Re: Universal anisochronism The Starmaker <starmaker@ix.netcom.com> - 2025-09-30 00:41 -0700
        Re: Universal anisochronism Tristan Wibberley <tristan.wibberley+netnews2@alumni.manchester.ac.uk> - 2025-10-15 11:03 +0100
  Re: Universal anisochronism Mikko <mikko.levanto@iki.fi> - 2025-09-29 12:43 +0300
    Re: Universal anisochronism Richard Hachel <rh@tiscali.fr> - 2025-09-29 14:18 +0000
      Re: Universal anisochronism The Starmaker <starmaker@ix.netcom.com> - 2025-09-29 08:46 -0700
      Re: Universal anisochronism Python <jpierre.messager@gmail.com> - 2025-09-29 15:52 +0000
        Re: Universal anisochronism Richard Hachel <rh@tiscali.fr> - 2025-09-29 19:19 +0000
          Re: Universal anisochronism Python <jpierre.messager@gmail.com> - 2025-09-29 21:35 +0000
      Re: Universal anisochronism Mikko <mikko.levanto@iki.fi> - 2025-09-30 16:02 +0300
        Re: Universal anisochronism Richard Hachel <rh@tiscali.fr> - 2025-09-30 13:37 +0000
          Re: Universal anisochronism Mikko <mikko.levanto@iki.fi> - 2025-10-01 13:22 +0300
        Re: Universal anisochronism Maciej Woźniak <mlwozniak@wp.pl> - 2025-09-30 15:47 +0200
          Re: Universal anisochronism Python <jpierre.messager@gmail.com> - 2025-09-30 14:00 +0000
            Re: Universal anisochronism Maciej Woźniak <mlwozniak@wp.pl> - 2025-09-30 16:10 +0200
              Re: Universal anisochronism Python <jpierre.messager@gmail.com> - 2025-09-30 14:22 +0000
                Re: Universal anisochronism Maciej Woźniak <mlwozniak@wp.pl> - 2025-09-30 16:31 +0200
                Re: Universal anisochronism Python <jpierre.messager@gmail.com> - 2025-09-30 14:39 +0000
                Re: Universal anisochronism Maciej Woźniak <mlwozniak@wp.pl> - 2025-09-30 16:50 +0200
                Re: Universal anisochronism Python <jpierre.messager@gmail.com> - 2025-09-30 14:52 +0000
                Re: Universal anisochronism Maciej Woźniak <mlwozniak@wp.pl> - 2025-09-30 17:10 +0200
                Re: Universal anisochronism Python <jpierre.messager@gmail.com> - 2025-09-30 15:18 +0000
                Re: Universal anisochronism Maciej Woźniak <mlwozniak@wp.pl> - 2025-09-30 17:47 +0200
                Re: Universal anisochronism Python <jpierre.messager@gmail.com> - 2025-09-30 16:24 +0000
                Re: Universal anisochronism Oleander Sadowski <nadre@ilasa.pl> - 2025-09-30 22:02 +0000
  Re: Universal anisochronism Python <jpierre.messager@gmail.com> - 2025-09-29 13:29 +0000
    Re: Universal anisochronism Maciej Woźniak <mlwozniak@wp.pl> - 2025-09-29 15:50 +0200
  Re: Universal anisochronism Thomas Heger <ttt_heg@web.de> - 2025-10-02 08:46 +0200
    Re: Universal anisochronism Richard Hachel <rh@tiscali.fr> - 2025-10-02 10:31 +0000

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