August 22, 2020
Ives, Stilwell, Otting, Billing, Doppler, canal rays, SRT, ART, GRT
In 1938 respective 1941 Ives and Stilwell from Bell Telephone Laboratories Inc. Performed remarkable experiments with canal rays (H 2 and 3 -ions) to prove the existence of a transverse Doppler effects on moving atomic clocks (as they called the moving ions) as SRT predicted. These measurements and the relativistic Doppler formula were apparently in best agreemend. Ives and Stilwell made measurements with an observation angle of 7° relative to the path of movement and not perpendicular as neccesary to obtain a real transversal effect. They pointed out on the first page, that it was not feasable to ensure an exact angle of 90° as slightest deviations would cause effects that are in the range of the expected effect. So this has to be seen as an angle depencency of the Doppler effect.
But the relativic expression for the second order Doppler is indeed independent of the angle. As it now turnes out the relativistic equation is not able to describe the measurements properly.