Re: Twin paradox revisited ll

On Jul 19, 12:20 pm, "Jeckyl" <no...@xxxxxxxxxxx> wrote:
"bill" <cosmo...@xxxxxxxxxxxxxxx> wrote in message

news:1184811186.008363.186360@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx



On Jul 18, 3:52 am, stevendaryl3...@xxxxxxxxx (Daryl McCullough)
wrote:
cosmo...@xxxxxxxxxxxxxxx says...

On Jul 15, 7:10 pm, "Martin Hogbin" <goatREMOVETHIS...@xxxxxxxxxx>
wrote:
No, it has little to do with the Doppler effect.

As the traveler moves away from the earth at a uniform velocity is his
image (or the radio messages that he sends) not red shifted from his
twin's point of view and is this effect not known as the Doppler
effect and is this not the information obtained by the twin that
causes him to conclude that the traveler is aging at the slower rate?

The Doppler effect applies in classical (non-relativistic) physics,
as well, but there is no differential aging in that case. The Doppler
effect doesn't cause the time dilation, and it also is not caused by
it. In the relativistic case, the Doppler shift formula takes into
account *both* the time lag due to the transit time for light,
and also the time dilation of the traveling twin. The classical
Doppler shift formula only takes into account
the time lag due to the transit time for light.

--
Daryl McCullough
Ithaca, NY

What *physical* information does the stay at home twin receive, other
than the frequency shift of the light or of radio messages from the
traveler's ship, that leads him to conclude that the traveler is aging
at the slower rate?

He doesn't need to get any information .. until the twin returns. Then we
can compare their clocks. The effect does not rely on the stay-at-home-time
receiving any information.

My question was in relation to the claim that from the stay at home
twin's point of view the traveler is aging at a slower rate than he is
*during* the outward bound trip.

As you correctly point out, we can only compare their clocks *after*
the traveler returns not, as claimed in that posting *during* the
trip.

Bill


.

Relevant Pages

  • Re: Twin paradox revisited ll
    ... image (or the radio messages that he sends) not red shifted from his ... but there is no differential aging in that case. ... the Doppler shift formula takes into ... traveler's ship, that leads him to conclude that the traveler is aging ...
    (sci.physics.relativity)
  • Re: Twin paradox revisited ll
    ... image (or the radio messages that he sends) not red shifted from his ... but there is no differential aging in that case. ... the Doppler shift formula takes into ... and also the time dilation of the traveling twin. ...
    (sci.physics.relativity)
  • Re: Twin paradox revisited ll
    ... image (or the radio messages that he sends) not red shifted from his ... but there is no differential aging in that case. ... the Doppler shift formula takes into ... and also the time dilation of the traveling twin. ...
    (sci.physics.relativity)
  • Re: Twin paradox revisited ll
    ... aging slower during the cruise phase of the flight. ... As the traveler moves away from the earth at a uniform velocity is his ... causes him to conclude that the traveler is aging at the slower rate? ... twin is aging at the faster rate what else is it that generates this ...
    (sci.physics.relativity)
  • Re: Twin paradox revisited ll
    ... causes him to conclude that the traveler is aging at the slower rate? ... twin is aging at the faster rate what else is it that generates this ... made this allowance they will then find that the other twin's clock ...
    (sci.physics.relativity)