A key reason for the development of the Quantum mechanical model of the atom is that of the radiating electron. An electron rotating in an orbital around the central proton (H-atom) will have acceleration (in linear space-time) and therefore will lose energy in the form of radiation and spiral in to the proton. Key understanding of the quantisation of atomic structure has developed since the concept of the proton-electron pair was discovered by Rutherford in 1911. Shortly after in 1913, Bohr successfully applied quantum theory to the H-atom in one of the most successful physical theories developed to date. Schrodinger, Dirac, Heisenberg and de Broglie all made significant contributions in developing wave mechanics. The success of quantum mechanics in enabling the accurate prediction of experimental observations has been unsurpassed. Black body radiation, the photo-electric effect and atomic spectra are among a number of examples. In 1914 Einstein presented the first of a series of papers outlining the theory of general relativity. General relativity has resulted in a fundamental shift in our understanding of physics; space-time is curved in the presence of fields. The Einstein Field equations show that the curvature of space-time is directly related to the energy-momentum tensor (tensor of the energy per unit volume) of the bodies under consideration. The field generates the energy and momentum of the system and is directly related to the energy momentum tensor. The gravitational field transfers energy and momentum to the "matter" in that it exerts forces upon it and gives it energy. The Einstein Field equation for gravitation is: