Schwarzschild Geometry

Schwarzschild had discovered his spacetime geometry as a solution to Einstein’s general relativistic field equation. It was the solution for the exterior of a static star, one that neither implodes nor explodes nor pulsates. However, in 1923 George Birkhoff, a mathematician at Harvard, had proved a remarkable mathematical theorem: Schwarzschild’s geometry describes the exterior of any star that is spherical, including not only static stars but also imploding, exploding, and pulsating ones.