In Arthur Eddington’s 1919 solar-eclipse expedition, the starlight measurements supported general relativity.
Einstein’s general theory of relativity predicted that gravity would curve spacetime and deflect light passing near the Sun. During a total solar eclipse, stars close to the Sun’s apparent position could be photographed because the Moon blocked the Sun’s bright disk. Their eclipse-position measurements could then be compared with photographs taken when the Sun was elsewhere.
Eddington led an expedition to Príncipe, while a second British team observed from Sobral in Brazil. The reported results were widely interpreted as supporting Einstein’s prediction. Newspapers soon made Einstein internationally famous, turning the eclipse into a landmark episode in the history of physics.
The original observations had substantial uncertainties, and later reanalyses have discussed the quality and weighting of the data. Modern tests using radio sources, gravitational lensing, and precision instruments provide much stronger evidence. The experiment did not test special relativity; it tested the gravitational bending of light predicted by general relativity.