Re: Einstein's Train Gedanken Re-visited

On Jun 23, 8:08 am, "Whoever" <no...@xxxxxxxxxxx> wrote:
"Bruce Richmond" <bsr3...@xxxxxxxxxxx> wrote in message

news:64a13f1e-3ef0-4599-b110-d8f97cf81068@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx





On Jun 23, 1:42 am, "Whoever" <no...@xxxxxxxxxxx> wrote:
"Bruce Richmond" <bsr3...@xxxxxxxxxxx> wrote in message

news:e5e3aac9-be6e-48e9-bb6a-2936b6dca28c@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx

On Jun 22, 11:38 pm, "Dono." <sa...@xxxxxxxxxxx> wrote:
On Jun 22, 5:33 pm, Bruce Richmond <bsr3...@xxxxxxxxxxx> wrote:

The Hafele-Keating experiment *was* conducted in the non inertial
frame of the earth's surface.  That is why the two directions did
not
give the same result.

The HKX was conducted in the air, about 30,000 ft from the eart's
surface.
The calculations for it were executed in the frame of reference whose
origin is coincident with the center of the Earth. This is the same
frame of reference as the one used by GPS calculations (called EFI in
the GPS). This frame is as close to an inertial frame as we can get..
The reason the clocks showed different elapsed times is the same one
as the one in the little problem I challenged Whoever to solve: the
palnes with the clocks on board had different speeds wrt EFI.

But the bottom line is that when the clocks were brought back together
on the surface of the earth their settings had changed.  We're not
talking about "according to calculations" here, we are talking their
actual settings as *measured* in the real world.

I think he means that the calculations of the expected results.  And the
observed results verified that (within experimental error).

I read it that you could change the results by choosing a different
frame to do the calculations in.  That's why I pointed out that the
experiment provided the actual result.

So .. what would happen if we moved the clocks apart at the same speed
according to the (almost) inertial frame of the center of the earth.  So
(for example) the one moving with the earth would stay 'still' (relative
to
the earth) and the other one move away at twice the speed of earth's
rotation in the opposite direction.

You would still get the effects.

Are you sure about that ?

Yes.

For starters what you proposed and what you described were not the
same thing. Your discription still had the clock(s) moving on the
earth's surface. So they are still moving along curved paths in the
ECI system. Combine that with the fact that even the ECI system is
not truly inertial and it becomes very unlikely that the effects will
cancel out.

http://en.wikipedia.org/wiki/Earth_Centered_Inertial

"It should be noted that ECI frames are not truly inertial since the
Earth itself is accelerating as it travels in its orbit about the
Sun."

Would they be synchronized relative to
the centre of the earth frame?  Would they be synchronized as far as an
observer that stayed with the first clock?  Could we then use those
clocks
for OWLS .. (if they aren't too far apart so one 'disappears' over the
horizon from the other) and would anyone object ?

I'm sure some would.

:)  But would they be justified :)

I think so. If you know that the clock is out of sync after a full
trip around the earth then why would you consider it to be in sync
after traveling part way? At what point do you decide that it is far
enough out of sync that you have to acknowledge the fact?

What if the second clock
went all the way around the earth and returned back to the first clock ..
do
you think they would they show the same time?

HK says they would not.

Are you sure about that?
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Relevant Pages

  • Re: Einsteins Train Gedanken Re-visited
    ... the one moving with the earth would stay 'still' ... see we need to make it explicit) what do you claim about the clocks ... appropriate speed would keep it in sync. ... frame would then be inertial. ...
    (sci.physics.relativity)
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  • Re: Einsteins Train Gedanken Re-visited
    ... the one moving with the earth would stay 'still' ... I thought the whole purpose of this exercise was to get clocks in sync ... frame would then be inertial. ...
    (sci.physics.relativity)
  • Re: Einsteins Train Gedanken Re-visited
    ... the one moving with the earth would stay 'still' ... I thought the whole purpose of this exercise was to get clocks in sync ... frame would then be inertial. ...
    (sci.physics.relativity)
  • Re: Einsteins Train Gedanken Re-visited
    ... The calculations for it were executed in the frame of reference ... The reason the clocks showed different elapsed times is the same ... on the surface of the earth their settings had changed. ... opposite directions at the same velocity and stop them ...
    (sci.physics.relativity)
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