Pound’s Falling Light Experiment and Einstein’s Elevator

The experiments with gamma radiation carried out by Pound et al. in the 1960s make use of the

Mőssbauer effect.  The counting rate of photons emitted from a height of h=22.5 m from a Fe57 source was measured versus the downward speed of the absorber.  It was found that the minimum transmission occurred at a speed equal to gh/c, thereby indicating that the excess speed of light was (gh/c2) c, i.e. the speed of light was found to be greater than c because of the gravitational effect on the photons. This is in very good agreement with the value predicted in 1907 by Einstein on the basis of his Equivalence Principle (EP) which claims that the effects of a gravitational field are indistinguishable from those of a uniform acceleration of the object.  However, it is pointed out that the EP fails to account for the fact that both the speed of light and the associated frequency vary in the same proportion with position of the source in the gravitational field, thereby indicating that the associated wavelength is invariant; the Doppler effect, on the other hand, when applied for the case of upward motion of the laboratory toward the source, leads to the conclusion that the wavelength should decrease in the same proportion as the frequency increases.  The fact that the effects of both gravity and the motion of circumnavigating atomic clocks need to be taken into account separately/additively to predict elapsed time delays measured relative to the corresponding clock that remained stationary at the originating airport is proof that the two effects are not equivalent.  The Uniform Scaling method is described which accounts for differences in measured values obtained in two different rest frames for all types of physical properties, thereby satisfying the original purpose foreseen for the EP.  


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