Linearized gravity

Linearized gravity is an approximation method in general relativity that applies perturbation theory to the metric tensor describing the geometry of spacetime. It assumes the gravitational field is weak, and writes the full spacetime metric as the flat Minkowski metric of special relativity plus a small perturbation term, so that the size of the perturbation is much less than one. Under this assumption, the highly nonlinear Einstein field equations reduce to a set of linear, second order partial differential equations that are far more tractable to solve. Linearized gravity is the standard framework used to study gravitational waves and weak-field gravitational lensing, both of which involve spacetime curvature modest enough for the weak-field approximation to hold, in situations where solving the full nonlinear Einstein equations directly would be impractical. This description is adapted from Wikipedia contributors under CC BY-SA 4.0; changes were made. https://creativecommons.org/licenses/by-sa/4.0/