Arthur Eddington

Sir Arthur Stanley Eddington (1882 - 1944)

Sir Arthur Eddington
Credit: United States Library of Congress' 
Prints and Photographs division

Arthur Eddington was a British astronomer, physicist and mathematician. He was born in Cumbria, UK before moving to Weston-super-Mare as a child. He was not from a wealthy family but did so well at school that he got a scholarship to go to Owen's College, Manchester. He graduated with a physics degree in 1902. Arthur was then offered a position at Trinity College, Cambridge where he completed his master’s degree. He worked at the Royal Observatory in Greenwich, London, before returning to Cambridge five years later.

He was the first person to propose that stars were powered by the nuclear fusion of hydrogen into helium. The limit to how bright a star can be before it begins to collapse is named after him, the Eddington Luminosity. 

He is most famous, for his work on Einstein's Theory of Relativity. Arthur carried out observations of a solar eclipse to confirm the theory. This work was considered so important that it prevented him beginning military service during the First World War. Arthur was happy about this as he was a pacifist, but he did offer to join an ambulance unit, or work as a harvest labourer on home soil.

Arthur viewed the eclipse from the island of Principe, off the west coast of Africa. He chose that location because there was a good chance of clear skies, and he could view the eclipse in full there. During the darkness of the eclipse, Arthur took photographs of stars close to the Sun. These stars are normally blocked by the light of the Sun during the day. Arthur observed that stars close to the Sun had their light shifted by the Sun's gravitational field. This confirmed Einstein's Theory of Relativity. 

He later wrote this short poem about the discovery:

Oh leave the Wise our measures to collate
One thing at least is certain, LIGHT has WEIGHT,
One thing is certain, and the rest debate—
Light-rays, when near the Sun, DO NOT GO STRAIGHT.