  I investigate the effect of the radiation drag force on a star moving
relative to the Cosmic Microwave Background (CMB) at z = 0. As expected, the
perturbation is extremely small and has no observable consequences on orbital
motions of stars within a galaxy or on orbital motions of galaxies within a
cluster. The energy dissipated by cubic meter in a galaxy via this mechanism is
10^{14} smaller than the energy density of the CMB and, thus, is a negligible
source of anisotropy. However, from the last scattering surface to population
III stars (30 < z < 1000), radiation drag on particles may have played a major
role in the apparition of anisotropy and rapid formation of densities.
