Lemaître-Tolman models and fine tuning the bang time of the universe

by Mr Peter Sundell (University of Turku, Department of Physics and Astronomy)

Wednesday 2 Oct 2013, 13:30 → 14:15 Europe/Stockholm

122:026

Lemaître-Tolman (LT) models have been successfully used in cosmology explaining most important cosmological observations without dark energy. A fine tuning problem arises from the homogeneity of the observations, which seems to demand that the universe was born everywhere at the same time. For the concordance ΛCDM model this is the only option, but for LT models this requires fine tuning as the bang time function in them is dependent on location. I study the possibility if there are observations satisfying LT models without fine tuning the bang time. I do this by assuming the universe to be old enough to contain some stabile structure, which would manifest itself by showing no redshift change in time from observables at the same location.