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. Arthur was not from a wealthy family. But he 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 come up with the idea that stars are 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 made observations of a solar eclipse to confirm the theory. Arthur viewed the eclipse from the island of Principe, off the west coast of Africa. He chose the island because there was a good chance of clear skies, and he could see the eclipse in full there. During the darkness of the eclipse, Arthur took photographs of stars close to the Sun. These stars are out-shined by the light of the Sun during the day. Arthur saw that the direction of the light from stars close to the Sun was changed by the pull of the Sun’s gravity. This confirmed Einstein's theory. 

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.

His work was thought to be so important that it stopped him from military service during the First World War. Arthur was happy about this as he was a pacifist. He did offer to join an ambulance unit, or sometimes work as a harvest labourer on home soil.