Objective Prior for Cosmological Parameters

Abstract

Jaynes’ transformation group method is applied to derive the uninfor- mative prior forthe parameters of the standard cosmological models. Scale invariance and invariance under a change of cosmic epoch, imply that in the usual (H, Ω) parametrisation, this improper prior takes the form [(H, Ω) α (HΩ|Ω−1|)⁻¹. The interpretation of this solution, and particularly of its singularity at the critical density Ω = 1, negates the existence of the so-called “flatness problem” of standard cosmology.