Best known for his observational confirmation of Einstein’s General Theory of Relativity, Sir Arthur Eddington was a prominent English astrophysicist of the early 20th Century, having his 136th birth anniversary today!
Arthur Stanley Eddington was born on December 28, 1882 in Kendal, Cumbria, England. His father, Arthur Henry Eddington, was the headmaster of a local school and his mother was Sarah Ann Shout. As a child, Arthur often tried to count the stars in the night sky and his interest got deeper into astronomy when he got a telescope at the age of 10. Arthur was a very bright student and won an entrance scholarship to Owens College, Manchester,when he was just 16. Eddington spent three years at the college and in 1902 he graduated with a First Class Honors degree in physics. Eddington then won a scholarship to Trinity College, Cambridge, and earned his Cambridge degree in 1905.
After graduating, Eddington spent some time researching thermionic emission at the Cavendish Laboratory in Cambridge. This did not go well, and meanwhile he spent time teaching mathematics to first year engineering students. Later, he was recommended by one of his senior colleague at Trinity College, for the position of chief assistant at the Royal Observatory in Greenwich where he was to embark on his career in astronomy. He remained there until 1913 and gained thorough training in practical astronomy. Besides his participation in the regular observing programs, Eddington had two special assignments, he went to Malta in 1909 to determine the longitude of the geodetic station there, and to Brazil in 1912 as a leader of an eclipse expedition.
During the World War I days, Arthur declared himself a pacifist .During these years he developed great interest in Einstein’s relativity and carried on important studies in astrophysics and relativity, in addition to teaching and lecturing. In 1919 he led an expedition to Príncipe Island (West Africa) that provided the first confirmation of Einstein’s theory that gravity will bend the path of light when it passes near a massive star. During the total eclipse of the sun, it was found that the positions of stars seen just beyond the eclipsed solar disk were slightly displaced away from the centre of the solar disk, just as predicted by the general theory of relativity. Hence, Eddington is credited for providing the earliest confirmations of Einstein’s theory of relativity.
In addition to his work in relativity theory, Eddington also did important work on the internal structure of stars. He discovered the mass-luminosity relationship for stars, he calculated the abundance of hydrogen, and produced a theory to explain the pulsation of Cepheid variable stars. Eddington was also a Smith’s prize winner for his essay on the proper motions of stars in 1907. Eddington was also the first to correctly speculate that the source of stellar energy was fusion of hydrogen into helium. Eddington spent most of his later life and career searching for a unified or fundamental theory of physics.
The Eddington limit, the natural limit to the luminosity of stars, or the radiation generated by accretion onto a compact object, is also named in his honour. Even a lunar crater and an asteroid was named after him. Eddington was knighted in 1930, and received the Order of Merit in 1938, along with receiving many other awards and honours from astronomical societies throughout the world. He never married and died in Cambridge, England on 22 November 1944, aged 61.
All the ground breaking discoveries that Eddington made throughout his life have been of utmost important to the scientific and physics community today and have changed the way we looked at the Universe. According to Eddington,
“Not only is the universe stranger than we imagine, it is stranger than we can imagine”
Truely a genius thought! Isn’t it?
Happy Birthday Sir!