Einstein-Hilbert Action

The Einstein-Hilbert action is a mathematical way to describe how gravity works in Einstein's theory of General Relativity. It captures the idea that the shape of spacetime—its curvature—is related to the distribution of mass and energy. By applying a principle called the "action principle," scientists use this formula to derive Einstein’s field equations, which tell us how matter and energy influence the curvature of spacetime. In essence, the Einstein-Hilbert action is the foundational mathematical expression that connects the fabric of the universe to the matter within it, guiding our understanding of gravity’s fundamental nature.