Abstract:
Einstein`s theory of General Relativity (GR) succeeded in describing a number of gravitational phenomena by being in agreement with astronomical observational measurements.
In spite of that, this theory kept being isolated from the other branches of physics because of its geometrical formulation and due to its being not amenable to quantization. Also, the cosmological application of GR yields certain difficulties and problems which need to be solved.
On the other hand an alternative model called the Generalized Field Equation (GFE) is found to be successful in explaining gravitational and cosmological phenomena, beside solving some cosmological problems. Despite these successes, the complex nature of the GFE makes it difficult to have a complete cosmological model based on it.
In this thesis the complex nature of the GFE is removed by using the so called coordinate condition , which simplifies the GFE in a manner similar to that played by the Lorentz gauge in simplifying Maxwell equations. This simplified version f the GFE is found to share with GR and the GFE all their cosmological successes, where it predicts the expansion of the universe, beside solving the horizon, entropy and flatness problems.
Unlike GR which has no successful model for solving the galaxy formation problem and GFE which did not touch upon this problem, this model introduces a solution for the galaxy formation problem. This solution is based on a non-linear gravitational equation which is obtained by employing the GFE on which the coordinate condition was applied. This equation will be suitable for solving the problem of the growth of galaxies during inflation, radiation and matter eras. Also this equation reduces to that of GR equation used in the area of weak gravity.
