Einstein's General Relativity provides the foundation for modern understanding of gravity. Modified gravity approaches often involve adjustments to the Einstein field equations through tensor modifications.
Einstein's theory of how matter and energy curve spacetime
General Relativity (GR) revolutionized our understanding of gravity. Rather than treating gravity as a force, Einstein's theory describes it as the curvature of spacetime caused by mass and energy.
The core principle is that massive objects create a curvature in the fabric of spacetime, and this curvature guides the motion of other objects. This is captured mathematically by the Einstein field equations:
Where is the Einstein tensor, is the cosmological constant, is the metric tensor, is Newton's gravitational constant, is the speed of light, and is the stress-energy tensor.