Indian scientist Amal Kumar Raychaudhuri established ‘Raychaudhuri equation’ in 1955 to describe gravitational focusing properties in cosmology. This equation is extensively used in general relativity, quantum field theory, string theory and the theory of relativistic membranes. This paper...

An exact solution of Einstein equation is easier than actual solution. The Schwarzschild metric is established on the basis of Einstein’s exact solution and it is also a static and stationary solution. The Schwarzschild solution expresses the geometry of a spherically symmetric massive...

The aim of the study is to describe the general upper limit of the age of the universe with the help of different cosmological models of the universe. Here homogeneous and isotropic assumptions of the observed universe are not strictly followed to calculate the present age of the universe....

The Friedmann, Robertson-Walker universe is based on the assumption that the universe is exactly homogeneous and isotropic. This model expresses that there is an all encompassing big bang singularity in the past as the origin from which the universe emerges in a very hot phase and continues its...