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Re: Ehrenfest paradox

From Thomas Heger <ttt_heg@web.de>
Newsgroups sci.physics.relativity
Subject Re: Ehrenfest paradox
Date 2024-01-04 08:23 +0100
Message-ID <kvn4g5F565hU1@mid.individual.net> (permalink)
References (4 earlier) <kv1rdhF6ggvU1@mid.individual.net> <kv4oabFnlskU1@mid.individual.net> <M3Ec439lLbV2TwZIYjdq7DeGz7s@jntp> <kvkholFl05uU1@mid.individual.net> <KG2wy65hw75wvxitHZq-cyYgJkg@jntp>

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Am 03.01.2024 um 11:56 schrieb Richard Hachel:
> Le 03/01/2024 à 08:47, Thomas Heger a écrit :
>> Am 28.12.2023 um 09:31 schrieb Richard Hachel:
>>> Le 28/12/2023 à 09:01, Thomas Heger a écrit :
>>>
>>>> Rotation is therefore 'absolute', while inertial motion isn't.
>>>
>>> There is a difference between a non-rotating disk moving Galileanly at
>>> Vo=0.8c from right to left, and a fixed disk rotating with a tangential
>>> speed of 0.8c.
>>
>>
>> I have not the faintest idea how you want to build a rigid disk with
>> tangential velocity of 0.8 c.
>>
>> That disk had to be extremely large and had do run insanely fast.
>>
>> This combinagtion would create tremendous tensions at the rim of the
>> disk, which will more than sufficiant to break the disk apart. (for
>> all possible rigid materials)
>>
>>
>>> These are therefore not, obviously, the same equations that must be
>>> used. For the disk in translation, it's easy, the Poincaré-Lorentz
>>> transformations are enough. For the rotating disk, the reflection
>>> becomes appalling, and a lot of people have thrown in the towel in the
>>> face of the simple Ehrenfest paradox.
>>
>> How in the world could someone calculate the relativistic effects of
>> nonsense.
>>
>>
>> TH
>
> This is not nonsense.

I would say: to have a tangential velocity of, say, 0.5 c on a rigid 
disk is plain nonsense.

For instance: Lets take a rigid disk with 100m diameter made from, say, 
very tough steel.

How fast does it have to rotate to get 0.5 c at the circumference?

Well, REALLY fast!

c~=300,000,000 m/s

v= 150,000,000 m/s=pi*100m *rotations_per_second

that is roughly 450,000 rotations per second

I would not believe for a minute, that an observer there would regard 
this as equivalent to being at rest.

Also the disk will most likely break and already at a much lower 
velocity than this.

> There can only be one physics in the world.
> If we can imagine a hyperrigid disk, why not?
> Furthermore, we don't have to go at speeds of 0.8c.
> Small relativistic effects can already be measured before.
> Finally, let's not forget the planets, which revolve around their sun,
> and sometimes even faster than Mercury (we found a large planet rotating
> very close and very quickly around its sun).
> And there, no need for a “full disk”.

No?

I mean: how would you create a rigid disk from vacuum?

...


TH

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Thread

Ehrenfest paradox Thomas Heger <ttt_heg@web.de> - 2023-12-24 09:17 +0100
  Re: Ehrenfest paradox nospam@de-ster.demon.nl (J. J. Lodder) - 2023-12-24 13:18 +0100
    Re: Ehrenfest paradox Richard Hachel <r.hachel@tiscali.fr> - 2023-12-25 16:26 +0000
      Re: Ehrenfest paradox Richard Hachel <r.hachel@tiscali.fr> - 2023-12-27 02:21 +0000
        Re: Ehrenfest paradox Thomas Heger <ttt_heg@web.de> - 2023-12-27 06:39 +0100
          Re: Ehrenfest paradox Thomas Heger <ttt_heg@web.de> - 2023-12-28 09:04 +0100
            Re: Ehrenfest paradox Richard Hachel <r.hachel@tiscali.fr> - 2023-12-28 08:31 +0000
              Re: Ehrenfest paradox Thomas Heger <ttt_heg@web.de> - 2024-01-03 08:51 +0100
                Re: Ehrenfest paradox Richard Hachel <r.hachel@tiscali.fr> - 2024-01-03 10:56 +0000
                Re: Ehrenfest paradox Maciej Wozniak <maluwozniak@gmail.com> - 2024-01-03 09:53 -0800
                Re: Ehrenfest paradox Thomas Heger <ttt_heg@web.de> - 2024-01-04 08:23 +0100
                Re: Ehrenfest paradox Richard Hachel <r.hachel@tiscali.fr> - 2024-01-04 10:05 +0000
                Re: Ehrenfest paradox Thomas Heger <ttt_heg@web.de> - 2024-01-05 07:26 +0100
                Re: Ehrenfest paradox Richard Hachel <r.hachel@tiscali.fr> - 2024-01-05 12:33 +0000
                Re: Ehrenfest paradox Thomas Heger <ttt_heg@web.de> - 2024-01-06 08:47 +0100
                Re: Ehrenfest paradox Richard Hachel <pourquoi-pas@tiscali.fr> - 2024-01-08 20:07 +0000
                Re: Ehrenfest paradox Thomas Heger <ttt_heg@web.de> - 2024-01-09 07:20 +0100
                Re: Ehrenfest paradox Richard Hachel <pourquoi-pas@tiscali.fr> - 2024-01-09 12:28 +0000
                Re: Ehrenfest paradox Thomas Heger <ttt_heg@web.de> - 2024-01-10 09:53 +0100
                Re: Ehrenfest paradox Richard Hachel <pourquoi-pas@tiscali.fr> - 2024-01-10 14:05 +0000
                Re: Ehrenfest paradox Thomas Heger <ttt_heg@web.de> - 2024-01-14 07:23 +0100
                Re: Ehrenfest paradox Richard Hachel <pourquoi-pas@tiscali.fr> - 2024-01-14 16:26 +0000
                Re: Ehrenfest paradox Gus Bähr Schultheiß <igsu@ybonrurg.dd> - 2024-01-14 19:49 +0000
                Re: Ehrenfest paradox Volney <volney@invalid.invalid> - 2024-01-14 18:50 -0500
                Re: Ehrenfest paradox Richard Hachel <pourquoi-pas@tiscali.fr> - 2024-01-15 00:14 +0000
                Re: Ehrenfest paradox Python <python@invalid.org> - 2024-01-15 01:17 +0100
                Re: Ehrenfest paradox Richard Hachel <pourquoi-pas@tiscali.fr> - 2024-01-15 00:51 +0000
                Re: Ehrenfest paradox Thomas Heger <ttt_heg@web.de> - 2024-01-15 08:12 +0100
                Re: Ehrenfest paradox Richard Hachel <pourquoi-pas@tiscali.fr> - 2024-01-15 13:37 +0000
                Re: Ehrenfest paradox Thomas Heger <ttt_heg@web.de> - 2024-01-16 09:37 +0100
                Re: Ehrenfest paradox Volney <volney@invalid.invalid> - 2024-01-15 15:42 -0500
                Re: Ehrenfest paradox Thomas Heger <ttt_heg@web.de> - 2024-01-16 09:44 +0100
                Re: Ehrenfest paradox nospam@de-ster.demon.nl (J. J. Lodder) - 2024-01-09 15:07 +0100
          Re: Ehrenfest paradox nospam@de-ster.demon.nl (J. J. Lodder) - 2023-12-28 13:18 +0100
            Re: Ehrenfest paradox Maciej Wozniak <maluwozniak@gmail.com> - 2023-12-28 04:46 -0800
            Re: Ehrenfest paradox Richard Hachel <r.hachel@tiscali.fr> - 2023-12-28 14:19 +0000
              Re: Ehrenfest paradox Python <python@invalid.org> - 2023-12-28 16:10 +0100
                Re: Ehrenfest paradox Richard Hachel <r.hachel@tiscali.fr> - 2023-12-28 16:16 +0000
              Re: Ehrenfest paradox JanPB <filmart@gmail.com> - 2023-12-28 15:03 -0800
                Re: Ehrenfest paradox Ross Finlayson <ross.a.finlayson@gmail.com> - 2023-12-28 19:34 -0800
                Re: Ehrenfest paradox Maciej Wozniak <maluwozniak@gmail.com> - 2023-12-28 21:05 -0800
            Re: Ehrenfest paradox Ross Finlayson <ross.a.finlayson@gmail.com> - 2023-12-28 10:14 -0800
              Re: Ehrenfest paradox Maciej Wozniak <maluwozniak@gmail.com> - 2023-12-28 11:04 -0800
                Re: Ehrenfest paradox Ross Finlayson <ross.a.finlayson@gmail.com> - 2023-12-28 11:08 -0800
              Re: Ehrenfest paradox Ross Finlayson <ross.a.finlayson@gmail.com> - 2023-12-28 19:32 -0800
            Re: Ehrenfest paradox Thomas Heger <ttt_heg@web.de> - 2023-12-31 08:08 +0100
              Re: Ehrenfest paradox Richard Hachel <r.hachel@tiscali.fr> - 2023-12-31 09:38 +0000
              Re: Ehrenfest paradox nospam@de-ster.demon.nl (J. J. Lodder) - 2024-01-04 12:00 +0100
                Re: Ehrenfest paradox Richard Hachel <r.hachel@tiscali.fr> - 2024-01-04 11:24 +0000
                Re: Ehrenfest paradox Tom Roberts <tjoberts137@sbcglobal.net> - 2024-01-04 12:18 -0600
                Re: Ehrenfest paradox Richard Hachel <r.hachel@tiscali.fr> - 2024-01-04 22:18 +0000
                Re: Ehrenfest paradox pnalsing@gmail.com (palsing) - 2024-01-04 23:07 +0000
                Re: Ehrenfest paradox Maciej Wozniak <maluwozniak@gmail.com> - 2024-01-04 21:56 -0800
                Re: Ehrenfest paradox pnalsing@gmail.com (palsing) - 2024-01-05 06:36 +0000
                Re: Ehrenfest paradox Maciej Wozniak <maluwozniak@gmail.com> - 2024-01-04 23:45 -0800
                Re: Ehrenfest paradox Richard Hachel <r.hachel@tiscali.fr> - 2024-01-05 12:18 +0000
                Re: Ehrenfest paradox nospam@de-ster.demon.nl (J. J. Lodder) - 2024-01-05 13:54 +0100
                Re: Ehrenfest paradox Maciej Wozniak <maluwozniak@gmail.com> - 2024-01-05 05:20 -0800
            Re: Ehrenfest paradox Laurence Clark Crossen <l.c.crossen@hotmail.com> - 2024-01-09 20:15 -0800
              Re: Ehrenfest paradox pnalsing@gmail.com (palsing) - 2024-01-10 05:12 +0000
                Re: Ehrenfest paradox Maciej Wozniak <maluwozniak@gmail.com> - 2024-01-09 23:31 -0800
    Re: Ehrenfest paradox Ross Finlayson <ross.a.finlayson@gmail.com> - 2023-12-28 01:15 -0800
    Re: Ehrenfest paradox JanPB <filmart@gmail.com> - 2023-12-28 15:00 -0800
      Re: Ehrenfest paradox nospam@de-ster.demon.nl (J. J. Lodder) - 2024-01-03 14:28 +0100
        Re: Ehrenfest paradox Maciej Wozniak <maluwozniak@gmail.com> - 2024-01-03 09:54 -0800
        Re: Ehrenfest paradox Richard Hachel <r.hachel@tiscali.fr> - 2024-01-03 18:09 +0000
          Re: Ehrenfest paradox Athel Cornish-Bowden <me@yahoo.com> - 2024-01-03 19:48 +0100
            Re: Ehrenfest paradox Adolf Göbel <adolfgoebel@aol.com> - 2024-01-03 22:21 +0100
          Re: Ehrenfest paradox JanPB <filmart@gmail.com> - 2024-01-03 11:25 -0800
  Re: Ehrenfest paradox wugi <wugi@brol.invalid> - 2023-12-28 22:31 +0100
    Re: Ehrenfest paradox Richard Hachel <r.hachel@tiscali.fr> - 2023-12-29 07:42 +0000
      Re: Ehrenfest paradox wugi <wugi@brol.invalid> - 2023-12-29 12:51 +0100
        Re: Ehrenfest paradox Richard Hachel <r.hachel@tiscali.fr> - 2023-12-29 12:58 +0000
          Re: Ehrenfest paradox Ross Finlayson <ross.a.finlayson@gmail.com> - 2023-12-29 07:55 -0800
        Re: Ehrenfest paradox Richard Hachel <r.hachel@tiscali.fr> - 2023-12-29 13:25 +0000
          Re: Ehrenfest paradox Python <python@invalid.org> - 2023-12-29 14:36 +0100
            Re: Ehrenfest paradox Richard Hachel <r.hachel@tiscali.fr> - 2023-12-29 13:43 +0000
              Re: Ehrenfest paradox Python <python@invalid.org> - 2023-12-29 14:45 +0100
                Re: Ehrenfest paradox Maciej Wozniak <maluwozniak@gmail.com> - 2023-12-29 06:48 -0800
            Re: Ehrenfest paradox Athel Cornish-Bowden <me@yahoo.com> - 2023-12-29 16:24 +0100
              Re: Ehrenfest paradox Richard Hachel <r.hachel@tiscali.fr> - 2023-12-29 15:29 +0000
                Re: Ehrenfest paradox Python <python@invalid.org> - 2023-12-29 20:33 +0100
                Re: Ehrenfest paradox Maciej Wozniak <maluwozniak@gmail.com> - 2023-12-29 12:11 -0800
                Re: Ehrenfest paradox Python <python@invalid.org> - 2023-12-29 21:22 +0100
                Re: Ehrenfest paradox Maciej Wozniak <maluwozniak@gmail.com> - 2023-12-30 01:34 -0800
                Re: Ehrenfest paradox Richard Hachel <r.hachel@tiscali.fr> - 2023-12-30 10:02 +0000
                Re: Ehrenfest paradox Athel Cornish-Bowden <me@yahoo.com> - 2023-12-30 11:06 +0100
                Re: Ehrenfest paradox Maciej Wozniak <maluwozniak@gmail.com> - 2023-12-30 02:33 -0800
                Re: Ehrenfest paradox Richard Hachel <r.hachel@tiscali.fr> - 2023-12-30 11:07 +0000
              Re: Ehrenfest paradox Python <python@invalid.org> - 2023-12-29 16:53 +0100
            Re: Ehrenfest paradox wugi <wugi@brol.invalid> - 2023-12-29 23:59 +0100
              Re: Ehrenfest paradox Maciej Wozniak <maluwozniak@gmail.com> - 2023-12-30 01:37 -0800
              Re: Ehrenfest paradox Richard Hachel <r.hachel@tiscali.fr> - 2023-12-30 17:59 +0000
                Re: Ehrenfest paradox Volney <volney@invalid.invalid> - 2024-01-03 23:30 -0500
    Re: Ehrenfest paradox Richard Hachel <r.hachel@tiscali.fr> - 2023-12-29 07:44 +0000

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