The Distribution of Galaxies in Relation to Their Formation and Evolution

The distribution of galaxies on the sky is not random, but has structure on a scale of ~ 30 Mpc. Similar structure in the cosmic background radiation is not present. Another expected source of structure in the background radiation is the finite size of the light horizon in the early Universe. The lack of observable structure in the background radiation implies extreme initial iso­tropy. Quantum effects may be responsible for this isotropy, and for the initial perturbations from which galaxies and clusters of galaxies formed.