Abstract

An observer in a cosmological constant dominated universe will experience de Sitter at late times. Heuristically a positive cosmological constant causes inhomogeneous and anisotropic contributions to dilute as the universe expands, allowing inhomogeneity to be systematically controlled by a late time expansion. I will apply a late time expansion to a Lambda-CDM universe, computing both cosmological solutions and luminosity distance as a function of redshift. The resulting expressions are nonlinear in the inhomogeneity and systematically characterise Lambda-CDM cosmologies which end in cosmological constant domination. Applied to Union 2 supernovae data the leading late time anisotropic correction can be measured, which takes the form of a large scale curvature tensor, whose components are found to be zero at the level of one part in 1000. With more data higher order inhomogeneous corrections can be measured.