The British astrophysicist who first proposed in 1920 that stars are powered by the fusion of hydrogen into helium — predicting fusion energy two decades before it was experimentally confirmed.
Sir Arthur Stanley Eddington (28 December 1882 – 22 November 1944) was born in Kendal, Westmorland, England. He studied at Owens College Manchester and Trinity College Cambridge, and served as Plumian Professor of Astronomy and Director of the Cambridge Observatory from 1914 until his death.[1]
Eddington’s argument was based on the mass defect: four hydrogen atoms weigh slightly more than one helium atom, and the difference, converted to energy via E = mc², could power a star for billions of years. This was confirmed when Hans Bethe worked out the specific reaction chains in 1938–1939.[2]
Eddington led the 1919 solar eclipse expedition that confirmed general relativity. His book The Internal Constitution of the Stars (1926) established the field of stellar astrophysics. He developed the Eddington luminosity limit and mass–luminosity relation for stars.[3]
Eddington was the first person to articulate the idea that humanity might one day harness fusion energy. His prediction, made 106 years before ITER’s projected first plasma, frames the entire fusion energy enterprise.