The article presents a new theory in physics which explains the interaction between gravity and light with mathematical results close to General Relativity (15 digits beyond the decimal point equal result) and unifies General Relativity with Quantum Physics by the fundamental elementary particle: the GEON. The GEON [1] is a fundamental solution of the relativistic quantum mechanical Dirac equation (Quantum Physics) and the confinement has been controlled by the fundamental interaction between Gravity and Light (General Relativity). The GEON is the most fundamental elementary particle and can be created by the compression of light into extremely high densities. The GEON appears when an equilibrium has been established between the expanding radiation pressure of light and the confining gravitational force of light. The GEON is the fundamental solution of the relativistic quantum mechanical Dirac equation. For this reason the GEON particle unifies Quantum Physics with General Relativity. The confinement of GEONS is only possible at discrete values. (Quantisation of Energy, Light and Gravity). The GEON carries the mass inside the structures of matter (Elementary Particles). The radius of a GEON with the mass of a proton (1.67×10-27 kg) equals 3 10-58 [m]. [30] PlotGraph 3, page 24 The new theory in physics has been based on the “divergence-free linear 4-dimensional stress-energy tensor in the Minkowski Space”. The difference between Einstein’s General Relativity and this theory is the different approach. Einstein has deformed (non-linear and non-divergence free) the “4-dimensional Stress-Energy Tensor” by introducing the curved 4-dimensional Riemannian Manifold to explain the interaction between Gravity and Light. The new theory describes the interaction between different fields (Electric, Magnetic and Gravitational) by identical interaction terms, generated by the separate divergence and the separate rotation of the different fields. (equation 24) The conclusion of the new theory is that “divergence-free” and “rotation-free” fields do not interact.When Isaac Newton published his 3 famous equations which became the foundation of Classical Dynamics, he was not aware that he was building the first elemental blocks for the Stress-Energy Tensor in the 4-dimensional Minkowski Space.When James Clerk Maxwell published his 4 famous equations which became the foundation for Classical Electrodynamics, he was not aware that he was building new blocks for the Stress-Energy Tensor in the 4-dimensional Minkowski Space.When Paul Dirac published his famous equation which became the foundation of Relativistic Quantum Physics, he was not aware that he was building further on blocks for the Stress-Energy Tensor in the 4-dimensional Minkowski Space.It was Albert Einstein who was one of the first physicists who discovered the importance of the Stress-Energy Tensor to describe in a mathematical way the interaction between Electromagnetic Radiation and a Gravitational Field.Because there was no match, Einstein deformed the Divergence-Free Linear “Stress-Energy Tensor” by deforming Space and Time. Using curved Riemannian manifolds, he deformed the fundamental Tensor in physics in such a way that he found a very special Mathematics to describe the interaction between Electromagnetic Radiation (Light) and a Gravitational Field. The Theory of General Relativity. This became a fundamental problem in physics. By deforming the fundamental building block in physics (the Divergence-Free Linear “Stress-Energy Tensor), there is no match anymore in the fundamental mainstreams in physics (classical mechanics, electrodynamics, quantum physics and general relativity). Classical Mechanics has no match with Classical Electrodynamics. Classical Electrodynamics has no match with Relativistic Quantum Physics. Relativistic Quantum Physics has no match with General Relativity.It is important to distinguish the “Physical Reality” from a Mathematical Description of it (which is in general an approach). The scalar curvature (or the Ricci scalar) is a measure of the curvature of a Riemannian manifold. Einstein used a curved Riemannian manifold to describe “Gravitational-Electromagnetic Interaction”. But the physics beyond this is the interaction between the different fields. It is possible to describe this in different ways. This new theory demonstrates a more direct approach in the force densities acting between different fields expressed by equation (24).