Some Solutions for Field equations of the Standard Cosmology

Abstract

Here we study how our universe starts in the big bang and then evolves into an open universe, closed, or flat depending on the constant curvature κ, the cosmological constant Λ, this constant should fulfill the role of repulsive force and the Hubble constant. The theory of general relativity seems to represent the only consistent way to address the problem of cosmology. Due to the Cosmological principle, we assume the universe is homogeneous and isotropic, we assume, in addition, we can characterize its contents like a perfect fluid, so that at scales large enough (greater than the distance furnishing between galaxies) we have defined a density ρ and pressure p. The equation of state p = p (ρ ) determines the type of fluid. The universe can be composed of different fluids ρ = ρ1 + ρ2 + ..., each one with different equations of state.