Late-time anisotropy and radiation drag within the cosmic microwave background

TL;DR

This paper examines the minimal impact of radiation drag on stars today but suggests it could have significantly influenced early universe anisotropy and structure formation between redshifts 30 and 1000.

Contribution

It introduces the potential role of radiation drag in early universe anisotropy and structure formation, a previously underexplored aspect.

Findings

Radiation drag force is negligible at present but may have been significant in the early universe.

Energy dissipation due to radiation drag is vastly smaller than CMB energy density today.

Radiation drag could have contributed to anisotropy and density formation in the early universe.

Abstract

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.