Microgravitational field resulting from Wienberg's inversion

On Aug 24, 10:07*pm, Tom Roberts wrote in
sci.physics.research:
Chalky wrote:
On Aug 19, 3:39 pm, John Polasek wrote:
A clock in the falling elevator would run slower due to the gravity
field there (vs infinity).

Yes. Plus a time-varying time dilation due to its changing relative
motion. Plus any variation due to its changing gravitational potential.
Plus any Doppler effects on the comparison to the distant clock.

The same clock would not run slower just
due to your linearly accelerating reference frame it it's not in a
gravity field.

Yes, but the time-varying time dilation would remain, plus any Doppler
effects.

Of course the occupant would have no way of checking this, which is
part of the equivalence principle. The effect is there, but he can't
detect it.

Hmmm. Claiming "the effect is there" is disingenuous when he can't
detect it.

In GR it is difficult to claim "this clock runs slower than that clock"
for ANY situation (using standard clocks), because standard clocks
always display their elapsed proper time. Remember that "slower" is
always a comparison, and the variations you ascribe to "running slower"
are MUCH better modeled as variations in the method of comparison and
differences in the clocks' paths through spacetime, rather than in the
clocks themselves.

This leads me to pose a further question. To the extent that the
accelerating frame can be considered to exactly counteract the
gravitational field, would this mean that the speed of light is now
constant in this accelerating frame even though it might be considered
to be non-constant (non locally) in both the accelerating frame (in
the absense of external gravity), and in the external gravitational
field?

You appear to be intermixing several different physical situations, ot
at least describing things ambiguously. Let me attempt to disentangle them.

A: Inside a freely-falling elevator in a gravitational field, one would
measure the vacuum speed of light to be isotropically c when using
standard clocks and rulers, to the extent that tidal effects are below
one's measurement accuracy.

B: An external observer at rest relative to the source of the
gravitation and watching the light rays inside that elevator of A would
conclude the light propagates anisotropically, as long as the
gravitation is large enough to generate differences bigger than his
measurement accuracy.

C: Inside an externally-accelerated elevator in flat spacetime (e.g. far
from any massive objects), one measures the vacuum speed of light to be
anisotropic and generally not equal to c, using standard clocks and
rulers, as long as the acceleration is large enough to generate
differences bigger than one's measurement accuracy. Note that by simply
waiting a sufficiently long time between clock synchronization and the
light-speed measurement one can detect the effects of any acceleration
along the light path (wait longer for smaller acceleration).

D: an external inertial observer watching the light rays inside the
elevator of C would conclude the light propagates isotropically in his
inertial frame with speed c, independent of the acceleration of the
elevator.

E: Inside an elevator at rest relative to the source of a gravitational
field, one obtains the same results as in C.

F: a freely-falling observer watching the light rays inside the elevator
of E would conclude the light propagates isotropically in his
locally-inertial frame with speed c, to the extent that tidal effects
are below his measurement accuracy (e.g. this requires him to be close
to the elevator).

Note in A the deviations from c are second order in small quantities
(tidal effects); in C they are first order in the acceleration (which
need not be small), and in the E they are first order in the
acceleration due to gravity (which need not be small).

Tom Roberts

Bravo Roberts bravo Tom bravo Albert Einstein of our generation
(Hawking is no longer the Albert Einstein of our generation)! Your "B"
and (after applying the equivalence principle) "C" seem to correspond
to the conditions of the Pound-Rebka experiment and, if so, why are
you so qualitative and not quantitative Honest Roberts? The obsever
will conclude the frequency shift is f'=f(1+V/c^2), and since the
speed of light is "not equal to c", the obsever will also conclude
that the shift in the speed of light is:

c' = c(1+V/c^2)? Honest Roberts?

c' = c(1+2V/c^2)? Honest Roberts?

Pentcho Valev