The physical basis of astronomical aberration

Abstract

The mechanism of stellar aberration was explained and formulated by Bradley in terms of the existence of a unique reference frame for light propagation. However, Einstein's denial of the existence of such a frame appears to undermine Bradley's interpretation of the phenomenon. It is suggested that the recent evidence for a cosmologically-based inertial reference frame provides a new physical basis for Bradley's explanation in a manner consistent with the requirements of special relativity. It is shown that a “delay” effect is also involved in our observation of the direction of nearby sources, and that the aberration and delay effects exactly compensate for nearby sources comoving with a terrestrial observer.