Structure of the cosmic microwave background

Abstract

We predict the structure expected in the cosmic microwave background over large angular scales in realistic anisotropic and inhomogeneous universes. In a homogeneous anisotropic universe we find that there exist two possibilities, a quadrupole or a hotspot pattern with and without dipole contributions. A hotspot allows a direct observational test of an open universe. We show how infinite wavelength inhomogeneous perturbations of the Friedman universe can be represented as ensembles of different homogeneous universes.