 Linearized gravity

Linearized gravity writes $g_{\mu \nu }={\eta }_{\mu \nu }+h_{\mu \nu }$ with $|h_{\mu \nu }|\ll 1$ and discards terms quadratic in $h$ and its derivatives.

Linearized gravity is an approximation of general relativity that simplifies the complex equations describing the gravitational field. It is based on the idea that the gravitational field can be treated as a small perturbation around a flat spacetime, typically Minkowski spacetime, which describes a region of spacetime without significant gravitational effects. In the framework of general relativity, the gravitational field is represented by the geometry of spacetime, which is described by the Einstein field equations.