On the Cosmology of the Rh=ct Universe

Abstract

Decades of astronomical observations show that the universe is undergoing accelerated expansion. The standard model of cosmology is the closest to a standard theory of gravitation. Still, it fails to adequately describe the universe without the ad hoc introduction of dark energy and dark matter to late-time cosmology and inflation to early-universe cosmology. This failure of the standard model has certainly created dilemmas for cosmology and the wider astronomical community, and several alternative cosmological models are currently being considered. Most current work is limited to the study of background dynamics, so a brief exploration of the dynamical evolution of the universe is presented in the context of an alternative cosmological model known as the Rh = ct model. This model is consistent with observations and has received particular attention in recent years. Like the ΛCDM model, the Rh = ct universe is based on an FLRW cosmology with the cosmic fluid’s total energy density ϵ and pressure p satisfying the condition of vanishing total active gravitational mass: ϵ + 3p = 0. The field equations corresponding to this universe will be solved, and the results derived will be compared to those from the standard model and analysed to see if the model allows for structure formation in the universe.