Reflections on general relativity from perspectives of black hole physics and Hořava-Lifshitz gravity.
The physical logic of the Theory of General Relativity is summarized employing differential geometry of surfaces in three dimensional Euclidean space as a visual assistance for understanding. The applications of general relativity in fields as cosmology and black hold physics is summarized. Of the unsolved problem such as cosmology of the very early universe, dark matter and dark energy, black hole singularity and quantization of gravity, some are more fundamental, while some are more about the specific application of general relativity to particular situations. As an application of general relativity, the Hawking temperature and tunneling rate for the Fermion tunnelling process was obtained for a regular black hole which has no singularity inside the body. Hořava-Lifshitz theory, proposed by some physicists as an attempt to fix the quantization problem of general relativity, is employed in the study of a holography problem.