Sir Arthur Stanley Eddington (December 28th, 1882 - November 22nd, 1944), scientific British, was one of most important the astrophysicists of the beginning of the 20th century. It is him which highlighted the limit which bears its name (Limite of Eddington) and which corresponds to the maximum Luminosité that can have a star of a mass given without starting to lose the roadbases of its atmosphere.
It is especially known for its work concerning the Theory of relativity. It is via one of its articles, Report one the relativity theory off gravitation , that the anglophone scientists discovered the theory of the General relativity of Albert Einstein. Indeed, because of First World War, German work or little was not diffused in the rest of the world.
Biography
Eddington was born with Kendal (Cumbrie) in a family Quaker. It was shown very early gifted for mathematics and gained various prices and purses which enabled him to finance its studies that it finished in 1905. It began research with the Laboratoire Cavendish, then research in mathematics which it quickly stopped and as of the end 1905, it accepted a station with the royal Observatoire of Greenwich. It was immediately implied there in a research project started in 1900 when photographic plates of the Astéroïde 433 Eros were taken during one year whole. The first assigned task with Eddington was to complete the analysis of these plates and to determine precisely the value of the solar parallax. In 1906, it began its statistical study of the movement of stars and, the following year, it gained a price for a test which it wrote on the subject.
In December 1912, George Darwin, a son of Charles Darwin and Professor plumien died and Eddington was named to replace it. Like the holder of the other pulpit of astronomy of Cambridge, the pulpit lowndesienne, also died him during the following year, Eddington became the director of the observatory of Cambridge, thus taking the responsability for theoretical and experimental astronomy in Cambridge.
During the First World War, Eddington was called to carry out its military service. Being Quaker and pacifist, he refused to be useful in the army and asked to carry out an alternative service but that was not possible there in this time. Scientific friends solved this problem while succeeding in pleading in its favor to raise it of its military obligations because of its importance for science. In 1915, it accepted via the Royal Astronomical Society the articles on the General relativity of Einstein and of Sitter. It then started to be interested on this subject, in particular because this new theory could provide an explanation to the unexplained excess of the advance of the Périhélie of Mercure. After the war, Eddington left for São Divide into volumes-and-Príncipe where a total eclipse of the sun was visible the May 29th 1919. According to general relativity, a visible star near the Sun should appear with a position slightly more distant from this one because its light should be slightly bent by the action of the Gravitation exerted by the mass of the Sun. This effect is observable only during one total sun eclipse, because if not the sunlight prevents from observing star in question. During the eclipse, Eddington took several photographs of the areas located around the Sun. The weather was bad and the plates photographic of bad quality and difficult to measure. It foot-note however in its notebook:
- … a plate that I measured gave of the results in agreement with Einstein.
Eddington also studied, the interior of stars and calculated their temperature while being based on energy necessary to counter the Pression exerted by the layers close to surface. By doing this, he discovered the Relation mass-luminosity stars. He calculated also abundance out of hydrogen and worked out a theory explaining the pulsation of the variable céphéides. The fruit of its research is contained in its important work The Internal Constitution off Stars (1926).
In 1920, on the basis of precise measurement of the atoms carried out by Francis Aston, it was the first to suggest that the energy source of stars came from the nuclear Fusion of the Hydrogène in Hélium. This assumption appeared correct but there was a long debate on this subject with James Jeans for which this energy came from the contraction of star on itself.
Years 1920 until its death, it concentrated more and more on what it called its fundamental Théorie of which the goal was the unification of the quantum theory, the Theory of relativity and of the Gravitation and who primarily based on a numerologic analysis of the adimensional relationship between constant fundamental. Of one moment, Eddington thought - starting from esthetic and numerologic arguments - that the Constante of fine structure which had been measured as being worth approximately 1/136 was worth exactly 1/136.
More recent measurements showed that it is not the case; the current value being estimated at 1/137,035 999 76 (50). When in 1938 of other measurements seemed to show that the value was closer to 1/137, it found an explanation connecting 137 to the Nombre of Eddington , its estimate of the exact number of electron S in the Univers: 747.724.136 275.002.577 605.653.961 181.555.468 . Its assumptions however were regarded as hazardous by its pars.
Eddington had been anobli in 1930 and accepted the Order of Merit in 1938. In addition to being elected in Royal Society, he was elected with the Royal Society off Edinburgh, the Royal Irish Academy, the National Academy off Sciences, like many other scientific companies.
Eddington died in Cambridge.
A lunar crater is named according to him, as well as the Astéroïde (2761) Eddington.
Eddington knew to popularize science by writing many books intended for the laymen. It is also known to have introduced the monkeys typists ( Infinite Monkey Theorem in English) in 1929 with the sentence:
- If an army of monkeys typed on typewriters, they could write all the books of the British Museum.
Distinctions
- 1923 : Gold medal of the Astronomical Society off the Pacific, of the Royal Astronomical Society and the National Academy off Washington
- 1928: Price Jules Jansen and gold medal of the Royal Society
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