Eddington's Solar Eclipse Observation

Eddington's Solar Eclipse Observation delivered the first empirical confirmation of general relativity, making it a 20th-century landmark. During the 1919 eclipse, Arthur Eddington measured starlight deflection of 1.98 arcseconds—remarkably close to Einstein's predicted 1.75 arcseconds and twice Newton's value of 0.87 arcseconds—a result 13% more accurate than the average prediction from competing theories. Compared to #8 Photoelectric Effect Experiment, Eddington's work required more complex logistics across two continents but provided more dramatic visual proof. This data point proved massive objects warp spacetime and vaulted Einstein to global fame.