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Groups > sci.physics.relativity > #432979

Re: Train gedanken - again.

From Thomas 'PointedEars' Lahn <PointedEars@web.de>
Newsgroups sci.physics.relativity
Subject Re: Train gedanken - again.
Date 2017-09-20 04:48 +0200
Organization PointedEars Software (PES)
Message-ID <2403458.mvXUDI8C0e@PointedEars.de> (permalink)
References <opr46v$jhn$1@dont-email.me> <ops8jj$1rqc$1@gioia.aioe.org>

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HGW wrote:

> On 19/09/17 22:56, Paul B. Andersen wrote:
>> The observations:
>> - At some time, Paul passes Ralph.
>> - At some later time, Ralph sees the flashes
>>     from the lightening bolts simultaneously.
>> - At some time, Paul sees the flash from the front,
>>     and shortly later, he sees the flash from the aft end.
>> - Ralph finds that he is midway between the marks in the ground.
> 
> According to SR:
> Since Paul is at the midpoint of the train and the flashes did not reach
> him simultaneously, the flashes were not absolutely simultaneous.
> Since Ralph is midway between the flashes and DOES see them
> simultaneously, the flashes WERE absolutely simultaneous.

That would be the case if the train, on which Ralph is located, were not 
moving relative to the places of the flashes.  But it is, and so he is: he 
is moving away from the place of the one flash and towards the place of the 
other, and so he is moving away from the light of the former and towards the 
light of the latter.

(Use a fixed-width Unicode font to read the following.)

  t₀:  ☇        R        ☇  Flashes strike
       ☇        P        ☇  Flashes strike

  t₁:    →       R     ←    Ralph has not seen either flash yet
         →      P      ←    Paul has not seen either flash yet

  t₂:      →      R  ←      Ralph has not seen either flash yet
           →    P    ←      Paul has not seen either flash yet

  t₃:        →     R←       Ralph has just seen the front flash
             →  P  ←        Paul has not seen either flash yet

  t₄:          → ←  R       Ralph has already seen the front flash,
                            but not the rear flash yet
               →P←          Front and rear flash are simultaneous for Paul

  t₅:          ← →   R      Ralph has already seen the front flash,
                            but not the rear flash yet
               ←P→          Paul has seen both flashes already

  t₆:        ←     →  R     Ralph has already seen the front flash,
                            but not the rear flash yet
             ←  P  →        Paul has seen both flashes already

  t₇:      ←         → R    Ralph has already seen the front flash,
                            but not the rear flash yet
           ←    P    →      Paul has seen both flashes already

  t₈:    ←             →R   Ralph finally sees the rear flash
         ←      P      →    Paul has seen both flashes already

(It’s so very simple, isn’t it?)
 
> .... so your experiment is impossible.

No, your logic is flawed.
 
> Your observations assume the flashes were at rest with the ground and
> moved at c in that frame.

First of all, not the flashes are moving towards the observers,
but the light from the flashes.

Second, the speed of light is the same in all frames of reference.  
Experimentally confirmed.

-- 
PointedEars

Twitter: @PointedEars2
Please do not cc me. / Bitte keine Kopien per E-Mail.

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Thread

Train gedanken - again. "Paul B. Andersen" <relativity@paulba.no> - 2017-09-19 14:56 +0200
  Train gedanken - again. "David (Kronos Prime) Fuller" <fuller.david@hotmail.com> - 2017-09-19 06:00 -0700
  Re: Train gedanken - again. Kos Etrakis <uar@ksskkwi.ck> - 2017-09-19 14:48 +0000
    Re: Train gedanken - again. Kos Etrakis <uar@ksskkwi.ck> - 2017-09-19 14:53 +0000
      Re: Train gedanken - again. Julio Di Egidio <julio@diegidio.name> - 2017-09-19 08:05 -0700
        Re: Train gedanken - again. mlwozniak@wp.pl - 2017-09-19 09:09 -0700
          Re: Train gedanken - again. Julio Di Egidio <julio@diegidio.name> - 2017-09-19 09:35 -0700
            Re: Train gedanken - again. mlwozniak@wp.pl - 2017-09-19 10:45 -0700
        Re: Train gedanken - again. Kos Etrakis <uar@ksskkwi.ck> - 2017-09-19 22:01 +0000
          Re: Train gedanken - again. Julio Di Egidio <julio@diegidio.name> - 2017-09-20 07:30 -0700
            Re: Train gedanken - again. Kos Etrakis <uar@ksskkwi.ck> - 2017-09-20 20:00 +0000
  Re: Train gedanken - again. mlwozniak@wp.pl - 2017-09-19 07:55 -0700
    Re: Train gedanken - again. Kos Etrakis <uar@ksskkwi.ck> - 2017-09-19 14:58 +0000
  Re: Train gedanken - again. HGW <HW@home.net> - 2017-09-20 09:18 +1000
    Re: Train gedanken - again. Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2017-09-20 04:48 +0200
      Re: Train gedanken - again. HGW <HW@home.net> - 2017-09-20 13:47 +1000
        Re: Train gedanken - again. Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2017-09-20 14:33 +0200
          Re: Train gedanken - again. HGW <HW@home.net> - 2017-09-21 09:05 +1000
            Re: Train gedanken - again. "David (Kronos Prime) Fuller" <fuller.david@hotmail.com> - 2017-09-20 16:07 -0700
            Re: Train gedanken - again. Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2017-09-22 01:24 +0200
              Re: Train gedanken - again. HGW <HW@home.net> - 2017-09-22 12:22 +1000
                Re: Train gedanken - again. Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2017-09-27 15:28 +0200
                Re: Train gedanken - again. Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2017-09-27 15:40 +0200
                Re: Train gedanken - again. HGW <HW@home.net> - 2017-09-29 09:20 +1000
                Re: Train gedanken - again. Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2017-09-29 08:49 +0200
                Re: Train gedanken - again. Odd Bodkin <bodkinodd@gmail.com> - 2017-09-29 12:08 +0000
                Re: Train gedanken - again. mlwozniak@wp.pl - 2017-09-29 05:59 -0700
                Re: Train gedanken - again. HGW <HW@home.net> - 2017-09-28 09:22 +1000
                Re: Train gedanken - again. Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2017-09-28 03:08 +0200
                Re: Train gedanken - again. gehan.ameresekere@gmail.com - 2017-09-27 20:30 -0700
        Re: Train gedanken - again. Odd Bodkin <bodkinodd@gmail.com> - 2017-09-20 20:42 +0000
          Re: Train gedanken - again. HGW <HW@home.net> - 2017-09-21 08:39 +1000
            Re: Train gedanken - again. Odd Bodkin <bodkinodd@gmail.com> - 2017-09-21 02:18 +0000
              Re: Train gedanken - again. HGW <HW@home.net> - 2017-09-22 08:25 +1000
                Re: Train gedanken - again. Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2017-09-22 01:37 +0200
                Re: Train gedanken - again. HGW <HW@home.net> - 2017-09-22 12:34 +1000
                Re: Train gedanken - again. Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2017-09-22 13:30 +0200
                Re: Train gedanken - again. HGW <HW@home.net> - 2017-09-23 06:44 +1000
                Re: Train gedanken - again. Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2017-10-10 00:24 +0200
                Re: Train gedanken - again. Odd Bodkin <bodkinodd@gmail.com> - 2017-09-22 03:02 +0000
                Re: Train gedanken - again. HGW <HW@home.net> - 2017-09-23 06:50 +1000
                Re: Train gedanken - again. Odd Bodkin <bodkinodd@gmail.com> - 2017-09-22 22:23 +0000
                Re: Train gedanken - again. HGW <HW@home.net> - 2017-09-23 10:08 +1000
                Re: Train gedanken - again. gehan.ameresekere@gmail.com - 2017-09-23 04:09 -0700
                Re: Train gedanken - again. Poutnik <poutnik@privacy.net> - 2017-09-23 13:32 +0200
                Re: Train gedanken - again. HGW <HW@home.net> - 2017-09-24 09:02 +1000
                Re: Train gedanken - again. kenseto <setoken@att.net> - 2017-09-24 06:31 -0700
                Re: Train gedanken - again. "Dono," <sa_ge@comcast.net> - 2017-09-23 19:37 -0700
                Re: Train gedanken - again. gehan.ameresekere@gmail.com - 2017-09-24 07:26 -0700
                Re: Train gedanken - again. Poutnik <poutnik@privacy.net> - 2017-09-24 16:44 +0200
                Re: Train gedanken - again. gehan.ameresekere@gmail.com - 2017-09-24 08:03 -0700
                Re: Train gedanken - again. Poutnik <poutnik@privacy.net> - 2017-09-24 17:35 +0200
                Re: Train gedanken - again. HGW <HW@home.net> - 2017-09-25 08:26 +1000
                Re: Train gedanken - again. gehan.ameresekere@gmail.com - 2017-09-24 17:36 -0700
                Re: Train gedanken - again. "Dono," <sa_ge@comcast.net> - 2017-09-24 18:24 -0700
                Re: Train gedanken - again. Poutnik <poutnik@privacy.net> - 2017-09-25 07:34 +0200
                Re: Train gedanken - again. HGW <HW@home.net> - 2017-09-25 15:49 +1000
                Re: Train gedanken - again. Poutnik <poutnik@privacy.net> - 2017-09-25 07:56 +0200
                Re: Train gedanken - again. gehan.ameresekere@gmail.com - 2017-09-25 00:00 -0700
                Re: Train gedanken - again. Poutnik <poutnik@privacy.net> - 2017-09-25 13:47 +0200
                Re: Train gedanken - again. mlwozniak@wp.pl - 2017-09-25 00:47 -0700
                Re: Train gedanken - again. gehan.ameresekere@gmail.com - 2017-09-24 23:53 -0700
                Re: Train gedanken - again. HGW <HW@home.net> - 2017-09-25 19:53 +1000
                Re: Train gedanken - again. gehan.ameresekere@gmail.com - 2017-09-25 02:58 -0700
                Re: Train gedanken - again. Poutnik <poutnik@privacy.net> - 2017-09-25 13:54 +0200
                Re: Train gedanken - again. "HGW, DSc." <HG@....> - 2017-09-26 03:15 +1000
                Re: Train gedanken - again. "David (Kronos Prime) Fuller" <fuller.david@hotmail.com> - 2017-09-25 10:19 -0700
                Re: Train gedanken - again. Poutnik <poutnik@privacy.net> - 2017-09-25 13:56 +0200
                Re: Train gedanken - again. "HGW, DSc." <HG@....> - 2017-09-26 03:11 +1000
                Re: Train gedanken - again. kenseto <setoken@att.net> - 2017-09-25 14:43 -0700
                Re: Train gedanken - again. gehan.ameresekere@gmail.com - 2017-09-26 01:26 -0700
                Re: Train gedanken - again. gehan.ameresekere@gmail.com - 2017-09-26 02:06 -0700
                Re: Train gedanken - again. HGW <HW@home.net> - 2017-09-27 08:39 +1000
                Re: Train gedanken - again. Poutnik <poutnik@privacy.net> - 2017-09-25 13:52 +0200
                Re: Train gedanken - again. "HGW, DSc." <HG@....> - 2017-09-26 03:18 +1000
                Re: Train gedanken - again. "David (Kronos Prime) Fuller" <fuller.david@hotmail.com> - 2017-09-25 10:21 -0700
                Re: Train gedanken - again. Poutnik <poutnik@privacy.net> - 2017-09-25 13:19 +0200
                Re: Train gedanken - again. HGW <HW@home.net> - 2017-09-25 15:48 +1000
                Re: Train gedanken - again. gehan.ameresekere@gmail.com - 2017-09-24 08:31 -0700
                Re: Train gedanken - again. Poutnik <poutnik@privacy.net> - 2017-09-24 17:46 +0200
                Re: Train gedanken - again. mlwozniak@wp.pl - 2017-09-24 09:30 -0700
                Re: Train gedanken - again. Paparios <mrios@ing.puc.cl> - 2017-09-24 08:04 -0700
                Re: Train gedanken - again. "Dono," <sa_ge@comcast.net> - 2017-09-24 08:24 -0700
                Re: Train gedanken - again. Odd Bodkin <bodkinodd@gmail.com> - 2017-09-23 14:11 +0000
                Re: Train gedanken - again. HGW <HW@home.net> - 2017-09-24 08:53 +1000
                Re: Train gedanken - again. Odd Bodkin <bodkinodd@gmail.com> - 2017-09-24 02:31 +0000
                Re: Train gedanken - again. HGW <HW@home.net> - 2017-09-24 16:39 +1000
                Re: Train gedanken - again. Odd Bodkin <bodkinodd@gmail.com> - 2017-09-24 12:34 +0000
                Re: Train gedanken - again. HGW <HW@home.net> - 2017-09-25 08:30 +1000
                Re: Train gedanken - again. Odd Bodkin <bodkinodd@gmail.com> - 2017-09-24 22:32 +0000
                Re: Train gedanken - again. HGW <HW@home.net> - 2017-09-25 09:41 +1000
                Re: Train gedanken - again. Odd Bodkin <bodkinodd@gmail.com> - 2017-09-25 02:51 +0000
                Re: Train gedanken - again. HGW <HW@home.net> - 2017-09-25 15:51 +1000
                Re: Train gedanken - again. Odd Bodkin <bodkinodd@gmail.com> - 2017-09-25 12:48 +0000
    Re: Train gedanken - again. "Paul B. Andersen" <relativity@paulba.no> - 2017-09-20 11:13 +0200
      Re: Train gedanken - again. mlwozniak@wp.pl - 2017-09-20 02:31 -0700
        Re: Train gedanken - again. gehan.ameresekere@gmail.com - 2017-09-20 02:34 -0700
          Re: Train gedanken - again. mlwozniak@wp.pl - 2017-09-20 03:25 -0700
  Re: Train gedanken - again. gehan.ameresekere@gmail.com - 2017-09-19 22:40 -0700
    Re: Train gedanken - again. Poutnik <poutnik@privacy.net> - 2017-09-20 08:08 +0200
      Re: Train gedanken - again. HGW <HW@home.net> - 2017-09-21 08:46 +1000
    Re: Train gedanken - again. Poutnik <poutnik@privacy.net> - 2017-09-20 08:33 +0200
      Re: Train gedanken - again. mlwozniak@wp.pl - 2017-09-20 00:04 -0700
      Re: Train gedanken - again. gehan.ameresekere@gmail.com - 2017-09-20 00:34 -0700
        Re: Train gedanken - again. gehan.ameresekere@gmail.com - 2017-09-20 00:42 -0700
          Re: Train gedanken - again. Poutnik <poutnik@privacy.net> - 2017-09-20 10:54 +0200
            Re: Train gedanken - again. HGW <HW@home.net> - 2017-09-21 08:49 +1000
              Re: Train gedanken - again. "David (Kronos Prime) Fuller" <fuller.david@hotmail.com> - 2017-09-20 15:59 -0700
              Re: Train gedanken - again. Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2017-09-22 01:54 +0200
                Re: Train gedanken - again. HGW <HW@home.net> - 2017-09-22 12:43 +1000
                Re: Train gedanken - again. Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2017-09-22 12:56 +0200
                Re: Train gedanken - again. "David (Kronos Prime) Fuller" <fuller.david@hotmail.com> - 2017-09-22 11:04 -0700
                Re: Train gedanken - again. HGW <HW@home.net> - 2017-09-23 07:36 +1000
                Re: Train gedanken - again. Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2017-09-27 01:38 +0200
                Re: Train gedanken - again. HGW <HW@home.net> - 2017-09-27 20:00 +1000
                Re: Train gedanken - again. Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2017-09-27 12:06 +0200
                Re: Train gedanken - again. HGW <HW@home.net> - 2017-09-28 09:30 +1000
                Re: Train gedanken - again. Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2017-09-28 03:04 +0200
                Re: Train gedanken - again. gehan.ameresekere@gmail.com - 2017-09-21 20:36 -0700
                Re: Train gedanken - again. Poutnik <poutnik@privacy.net> - 2017-09-22 07:21 +0200
                Re: Train gedanken - again. Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2017-09-26 21:57 +0200
                Re: Train gedanken - again. gehan.ameresekere@gmail.com - 2017-09-26 20:57 -0700
                Re: Train gedanken - again. "Dono," <sa_ge@comcast.net> - 2017-09-26 21:00 -0700
                Re: Train gedanken - again. Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2017-09-27 15:24 +0200
                Re: Train gedanken - again. gehan.ameresekere@gmail.com - 2017-09-27 17:39 -0700
                Re: Train gedanken - again. Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2017-09-28 02:52 +0200
        Re: Train gedanken - again. Poutnik <poutnik@privacy.net> - 2017-09-20 10:48 +0200
    Re: Train gedanken - again. "Paul B. Andersen" <relativity@paulba.no> - 2017-09-20 15:13 +0200
  Re: Train gedanken - again. "Paul B. Andersen" <relativity@paulba.no> - 2017-09-20 20:19 +0200
    Re: Train gedanken - again. Kos Etrakis <uar@ksskkwi.ck> - 2017-09-20 20:02 +0000
    Re: Train gedanken - again. HGW <HW@home.net> - 2017-09-21 09:10 +1000
      Re: Train gedanken - again. "Paul B. Andersen" <relativity@paulba.no> - 2017-09-21 12:46 +0200
  Re: Train gedanken - again. kenseto <setoken@att.net> - 2017-09-20 13:14 -0700
    Re: Train gedanken - again. mitchrae3323@gmail.com - 2017-09-20 13:27 -0700
    Re: Train gedanken - again. HGW <HW@home.net> - 2017-09-21 09:29 +1000
    Re: Train gedanken - again. "Paul B. Andersen" <relativity@paulba.no> - 2017-09-21 14:03 +0200
      Re: Train gedanken - again. mlwozniak@wp.pl - 2017-09-21 05:19 -0700
      Re: Train gedanken - again. Kos Etrakis <uar@ksskkwi.ck> - 2017-09-21 12:42 +0000
      Re: Train gedanken - again. kenseto <setoken@att.net> - 2017-09-21 07:24 -0700
        Re: Train gedanken - again. "Paul B. Andersen" <relativity@paulba.no> - 2017-09-21 22:16 +0200
          Re: Train gedanken - again. HGW <HW@home.net> - 2017-09-22 08:51 +1000
            Re: Train gedanken - again. Odd Bodkin <bodkinodd@gmail.com> - 2017-09-22 03:02 +0000
              Re: Train gedanken - again. "David (Kronos Prime) Fuller" <fuller.david@hotmail.com> - 2017-09-21 20:18 -0700
          Re: Train gedanken - again. gehan.ameresekere@gmail.com - 2017-09-21 20:39 -0700
            Re: Train gedanken - again. "David (Kronos Prime) Fuller" <fuller.david@hotmail.com> - 2017-09-21 20:42 -0700
            Re: Train gedanken - again. Poutnik <poutnik@privacy.net> - 2017-09-22 07:49 +0200
              Re: Train gedanken - again. gehan.ameresekere@gmail.com - 2017-09-21 23:51 -0700
                Re: Train gedanken - again. Poutnik <poutnik@privacy.net> - 2017-09-22 09:04 +0200
                Re: Train gedanken - again. Poutnik <poutnik@privacy.net> - 2017-09-22 09:08 +0200
                Re: Train gedanken - again. gehan.ameresekere@gmail.com - 2017-09-22 00:27 -0700
                Re: Train gedanken - again. Poutnik <poutnik@privacy.net> - 2017-09-22 11:52 +0200
                Re: Train gedanken - again. mlwozniak@wp.pl - 2017-09-22 04:05 -0700
                Re: Train gedanken - again. HGW <HW@home.net> - 2017-09-23 07:46 +1000
                Re: Train gedanken - again. Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2017-09-27 12:26 +0200
                Re: Train gedanken - again. HGW <HW@home.net> - 2017-09-28 09:31 +1000
                Re: Train gedanken - again. Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2017-09-28 03:01 +0200
                Re: Train gedanken - again. gehan.ameresekere@gmail.com - 2017-09-27 20:22 -0700
                Re: Train gedanken - again. Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2017-09-28 12:00 +0200
            Re: Train gedanken - again. "Paul B. Andersen" <relativity@paulba.no> - 2017-09-22 14:08 +0200
              Re: Train gedanken - again. HGW <HW@home.net> - 2017-09-23 07:41 +1000
                Re: Train gedanken - again. Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2017-09-27 12:28 +0200
                Re: Train gedanken - again. HGW <HW@home.net> - 2017-09-28 09:32 +1000
                Re: Train gedanken - again. Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2017-09-28 03:02 +0200
          Re: Train gedanken - again. kenseto <setoken@att.net> - 2017-09-22 07:03 -0700
            Re: Train gedanken - again. "Paul B. Andersen" <relativity@paulba.no> - 2017-09-22 19:55 +0200
              Re: Train gedanken - again. HGW <HW@home.net> - 2017-09-23 07:42 +1000
              Re: Train gedanken - again. kenseto <setoken@att.net> - 2017-09-23 06:55 -0700
                Re: Train gedanken - again. "Paul B. Andersen" <relativity@paulba.no> - 2017-09-24 11:17 +0200
      Re: Train gedanken - again. HGW <HW@home.net> - 2017-09-22 08:30 +1000
        Re: Train gedanken - again. "Paul B. Andersen" <relativity@paulba.no> - 2017-09-22 13:52 +0200
          Re: Train gedanken - again. mlwozniak@wp.pl - 2017-09-22 05:34 -0700
          Re: Train gedanken - again. HGW <HW@home.net> - 2017-09-23 08:05 +1000
            Re: Train gedanken - again. "Paul B. Andersen" <relativity@paulba.no> - 2017-09-23 15:38 +0200
              Re: Train gedanken - again. HGW <HW@home.net> - 2017-09-24 09:12 +1000
                Re: Train gedanken - again. "David (Kronos Prime) Fuller" <fuller.david@hotmail.com> - 2017-09-23 16:17 -0700
                Re: Train gedanken - again. "Paul B. Andersen" <relativity@paulba.no> - 2017-09-24 11:03 +0200
                Re: Train gedanken - again. kenseto <setoken@att.net> - 2017-09-24 07:11 -0700
                Re: Train gedanken - again. gehan.ameresekere@gmail.com - 2017-09-24 07:38 -0700
                Re: Train gedanken - again. HGW <HW@home.net> - 2017-09-25 08:43 +1000
                Re: Train gedanken - again. "Paul B. Andersen" <relativity@paulba.no> - 2017-09-25 14:38 +0200
                Re: Train gedanken - again. kenseto <setoken@att.net> - 2017-09-25 07:15 -0700
                Re: Train gedanken - again. kenseto <setoken@att.net> - 2017-09-25 07:38 -0700
                Re: Train gedanken - again. "HGW, DSc." <HG@....> - 2017-09-26 04:20 +1000
                Re: Train gedanken - again. gehan.ameresekere@gmail.com - 2017-09-26 01:23 -0700
              Re: Train gedanken - again. kenseto <setoken@att.net> - 2017-09-24 06:48 -0700

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