Distribution of Blackbody Cavity Radiation in a Moving Frame of Reference

Abstract

Blackbody cavity radiation is considered from the point of view of an observer in arbitrary uniform motion with respect to the c.m. of the radiation. It is found that the only effect of the motion is to introduce an angle-dependent effective temperature, which replaces the rest-frame temperature of the cavity. The results are applied to the question of the earth's motion through the 3\ifmmode^\circ\else\textdegree\fi{}K cosmic radiation.