POUND-REBKA EXPERIMENT : ALL POSSIBILITIES

The top of a tower of height h emits light with (initial) frequency f, speed c and wavelength L. Observers on the ground (Pound and Rebka) measure the frequency to be f'=f(1+gh/c^2), the speed c' and the wavelength L'. Hypotheses:

A. Gravitational time dilation does exist.

B. There is no gravitational time dilation.

C. Photons do accelerate in a gravitational field.

D. Photons do not accelerate in a gravitational field.

E. c' = c(1+gh/c^2)

F. c' = c(1+2gh/c^2)

G. c' = c

H. L' = L/(1+gh/c^2)

I. L' = L

Even if we do not know which hypothesis is true and which false, we may still try to find consistent combinations which satisfy the formula:

(frequency) = (speed of light)/(wavelength)

In my view, consistent combinations a

A,D,E,I

B,C,E,I

B,D,G,H

Note that there is no consistent combination for F, the variation of the speed of light predicted by Einstein's general relativity.

Pentcho Valev

The top of a tower of height h emits light with frequency f, speed c and wavelength L (as measured by the emitter):

f = c/L

An observer on the ground measures the frequency to be f'=f(1+gh/c^2), the speed of light to be c' and the wavelength to be L':

f' = c'/L'

Crucial questions: c'=? L'=?

Newton's emission theory of light:

c' = c(1+gh/c^2)

L' = c'/f' = L

Einstein's relativity:

c' = c(1+2gh/c^2)

L' = c'/f'

Needless to say, the answer given by Einstein's relativity is absurd so no Einsteinian would pronounce it explicitly. Occasionally Einsteinians active on the sci.physics.relativity forum offer another answer (which has nothing to do with the original 1915 theory):

c' = c

L' = c'/f'

The problem with this answer is that it is incompatible with gravitational time dilation. The answer implies that the frequency shift (measured by Pound and Rebka) is entirely due to a shift in the wavelength. Then there is no place for gravitational time dilation in this scenario - another factor (the shifted wavelength) has already done the job.

Pentcho Valev