Arthur Eddington

Sir Arthur Stanley Eddington was an English astronomer, physicist, and mathematician whose profound grasp of relativity and stellar interiors transformed astrophysics in the early twentieth century. Educated at Trinity College, Cambridge, and serving as Plumian Professor of Astronomy and director of Cambridge Observatory, Eddington was the foremost English-speaking exponent of Albert Einstein's theories.

In May 1919, Eddington led an expedition to the West African island of Príncipe during a total solar eclipse. Measuring the apparent deflection of starlight grazing the sun's gravitational field, his photographic plates confirmed Einstein's prediction of gravitational light bending over Newtonian mechanics, instantly vaulting Einstein into global superstardom. Eddington also discovered the Eddington luminosity limit—the maximum brightness a star can achieve before radiation pressure blows away its outer layers—and was the first to propose that stars generate their immense power through the thermonuclear fusion of hydrogen into helium.