High-dimensional Theory Of Gravity, Spherically Symmetric Solutions Of A Class Of Physical Explanation

In order to unify gravitation with other interactions, Kaluza and Klein extended Einstein' s General Relativity to higher dimensions. On the basis of reviewing Kaluza-Klein theory, this dissertation emphasizes on discussing a five-dimensional (5D) time-dependent and spherically symmetric exact solution presented by Liu and Wesson in 2001. This 5D solution is 5D Ricci-flat and 5D empty. From this 5D solution and using Campbell' s embedding theorem, a 4D solution is derived which is 4D sourceful. This dissertation gives detailed study to this 4D solution, especially to the equivalent or induced 4D energy-momentum tensor of the solution. It is found that this 4D solution can be interpreted as to describe exterior fields of a spherically symmetric star immersed in a homogenous and isotropic cosmic background radiation. This star has a non-zero temperature and there is heat conduction between the star and the surrounding radiation. Possible experimental tests are discussed briefly.