Transverse redshift effects without special relativity

Abstract

Transverse redshift effects are sometimes presented as being unique to special relativity (the "transverse Doppler effect"). We argue that if the detector is aimed at 90 degrees in the laboratory frame, most theories will predict a redshifted frequency at the detector, although these predictions can be concealed by specifying that angles should be defined in a frame /other/ than the laboratory frame. These redshifts are often stronger than special relativity's predictions. We list some of the situations in which lab-transverse redshifts would be expected.