A flat space-time model of the Universe
  We propose a model of the Universe based on Minkowski flat space-time metric. In this model the space-time does not evolve. Instead the matter evolves such that all the mass parameters increase with time. We construct a model based on unimodular gravity to show how this can be accomplished within the framework of flat space-time. We show that the model predicts the Hubble law if the masses increase with time. Furthermore we show that it fits the high z supernova data in a manner almost identical to the standard Big Bang model. Furthermore we show that at early times the Universe is dominated by radiative energy density. The phenomenon of recombination also arises in our model and hence predicts the existence of CMBR. However a major difference with the standard Big Bang is that the radiative temperature and energy density does not evolve in our model. Furthermore we argue that the basic motivation for inflation is absent in our model. 
Pankaj Jain
astro-ph.CO gr-qc