General relativity
Gravity is not a force but the shape of spacetime, and starlight bends to prove it.
- When
- —
- Duration
- 4 years
- Known to
- ± 1 year
- Era
- Industrial, Holocene
Einstein's 1915 field equations describe gravity as the curvature of spacetime by mass and energy. The theory explains an anomaly in Mercury's orbit that had defeated Newtonian mechanics, and predicts that light passing the Sun will bend by a specific amount. Eddington's eclipse expedition in 1919 measures it, and Einstein becomes internationally famous overnight — an unusual case of a physics result on the front pages.