Re: Einstein's Train Gedanken Re-visited

On Jun 23, 11:36 pm, Bruce Richmond <bsr3...@xxxxxxxxxxx> wrote:
On Jun 23, 10:54 pm, "Whoever" <no...@xxxxxxxxxxx> wrote:





"Bruce Richmond" <bsr3...@xxxxxxxxxxx> wrote in message

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

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

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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.

Yes .. they are

Your discription still had the clock(s) moving on the
earth's surface.

No .. it clearly didn't.  Only one of them.

Ok, I'll grant you that.  I misinterperted what you were saying.





==>> >> 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.

==

See there "the one moving with the earth would stay 'still' (relative to the
earth) "

So they are still moving along curved paths in the
ECI system.

Yes they are

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."

Grr ... Picky .. so the only affect is due to the movement of the earth
around the sun and the sun around galactic core, and whatever non-inertial
movement the galaxy may have.

So .. ignoring those effects .. treating the ECI as inertial for the sake of
this thought experiment .. (which seemed to be obvious from context, but I
see we need to make it explicit) what do you claim about the clocks as
described?- Hide quoted text -

- Show quoted text -

I thought the whole purpose of this exercise was to get clocks in sync
without using light signals so that a real world experiment could be
done to measure one way light speed isotropy.

Yes if you move two side by side synched clocks symmetrically in the
opposite directions at the same velocity and stop them
simultaneously....these two clocks will remain synchronized according
to SR. These two clocks can be used to measure the OWLS directly.

Ken Seto



So besides the slight non-inertial effects you mentioned above you
will also have the problem that the clock will get out of sync due to
the acceleration to get it up to speed and deceleration stop it.

You also have the problem that after stopping the transported clock,
even if it is in sync, the clocks are not at rest in the ECI system.
If you manage to throw a ball to someone on the other side of a merry-
go-round while it is spinning its time of flight will be different
than if it weren't spinning.

Yes, it's my turn to be picky ;)~- Hide quoted text -

- Show quoted text -- Hide quoted text -

- Show quoted text -

.

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