Einstein's Field Equations

Spacetime geometry and the distribution of matter and energy are coupled: gravity becomes the curvature of spacetime, from Mercury's orbit and GPS clocks to black holes, gravitational waves and the expanding universe

Einstein's Field Equations — Flamm's paraboloid around a black hole, the anatomy of the equations, the Newtonian limit and GPS clocks, Mercury's perihelion, light bending and photon paths, black-hole potentials and shadow sizes, the Hulse–Taylor pulsar, the GW150914 chirp and the expansion of the universe