If gravity is a consequence of spacetime curvature why is a graviton needed a graviton makes sense for a force field gravity but not for a spacetime curvature gravity?

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The most commonly accepted model used to describe gravity is a set of equations (and their solutions) put forth by Einstein in his General Theory of Relativity. Einstein theorized that matter is responsible for spacetime curvature, which in turn affects the movements of inertial objects - the observable effect of which is the acceleration we call gravity. If Einstein's physics perfectly correlated with all observable phenomena in nature, then there may be no need for us to be concerned about the possible existence of a 'graviton' particle. However, there are some anomalies in the universe (such as the orbital velocity of stars around the outskirts of galaxies; or the accelerating expansion of the universe) that cannot be explained by the current model. Therefore, some physicists are investigating ways to enhance our understanding of gravitational mechanics, and Quantum Mechanics is one of those avenues of exploration; due to its success in using the behaviour of subatomic particles to explain the universe around us. A 'graviton' is a hypothetical elementary particle in Quantum Field Theory; its nature and characteristics have already been derived - but it hasn't been discovered yet. If it does exist, then such a finding would go a long way towards refining our current knowledge on how gravity works... it may even revolutionise our understanding of this topic. That's why it is important to consider the 'graviton' - which I think is the question that you were asking.

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First answer by Sukidarkra. Last edit by ID3087332759. Question popularity: 2 [recommend question].