Eddington, Arthur Stanley (1882–1944)
Arthur Eddington was an English astronomer and astrophysicist who pioneered the theoretical study of stellar structure. Through his Mathematical Theory of Relativity (1923), he did much to introduce the English speaking world to the theories of Albert Einstein.
Educated at the universities of Manchester and Cambridge, he spent seven years as chief assistant at the Royal Greenwich Observatory and 41 as Plumian Professor at Cambridge. He made important investigations of stellar dynamics, and was an influential supporter of the view that the spiral nebulae were external galaxies. He contributed much to the introduction of Einstein's general theory of relativity into cosmology, writing books on the new theory for both his fellow scientists and the public, and led one of the two 1919 solar eclipse expeditions that confirmed the predicted bending of starlight by gravity. Eddington's greatest contributions concerned the astrophysics of stars. He dealt with the importance of radiation pressure, the transfer of energy by radiation, the mass-luminosity relation, pulsations in Cepheid variables, and the very high densities of white dwarfs, and was among the first to argue that subatomic reactions must power the stars. See also Eddington limit and Eddington number.