Arthur Eddington
On the 28th of December 1882, Arthur Stanley Eddington was born in Kendal, Westmorland. His parents were Quakers who valued education and quiet reflection. His father taught at a Quaker training college before moving to become headmaster of Stramongate School. The family lived in a house called Varzin at 42 Walliscote Road in Weston-super-Mare. A plaque on that building now explains his contributions to science.
His father died in the typhoid epidemic which swept England in 1884. Sarah Ann Shout raised her two children with relatively little income. Stanley spent three years at a preparatory school after being educated at home initially. He entered Brynmelyn School in 1893 as a most capable scholar. Mathematics and English literature became his strengths early on.
He earned a scholarship to Owens College, Manchester in 1898. He turned to physics for the next three years after a general course. Arthur Schuster and Horace Lamb influenced him greatly during this time. Dalton Hall housed him while he came under the lasting influence of J. W. Graham. He graduated with First Class Honours in 1802.
Trinity College, Cambridge awarded him a scholarship based on his performance. Robert Alfred Herman served as his tutor there. In 1904 Eddington became the first ever second-year student to be placed as Senior Wrangler. He received his M.A. in 1905 before beginning research on thermionic emission. The Cavendish Laboratory did not go well for him initially. He taught mathematics to engineering students briefly. A recommendation by E. T. Whittaker secured his position at the Royal Observatory, Greenwich.
Eddington began investigating stellar interiors in 1916 through theory. He extended Karl Schwarzschild's earlier work on radiation pressure within Emden polytropic models. These models treated a star as a sphere of gas held up against gravity by internal thermal pressure. Radiation pressure was necessary to prevent collapse of the sphere according to his calculations.
He developed his model despite knowingly lacking firm foundations for understanding opacity and energy generation inside stars. His results allowed calculation of temperature, density and pressure at all points within a star. James Jeans contributed the suggestion that stellar matter would certainly be ionized. Collaboration between the pair ended after their famous debates.
Around 1920 he anticipated nuclear fusion processes in stars through his paper titled The Internal Constitution of the Stars. At that time the source of stellar energy remained a complete mystery. Eddington correctly speculated that hydrogen fused into helium liberating enormous energy via Einstein's equation. Francis Aston had recently shown the mass of a helium atom was about 0.8% less than four hydrogen atoms combined.
Observations of Cepheid variable stars showed rotation did not visibly speed up as contraction hypotheses predicted. Only conversion of matter to energy seemed plausible given known physics. If a star contained just 5% fusible hydrogen it would suffice to explain how stars got their energy. All these speculations were proven correct in following decades.
In 1924 he discovered the mass-luminosity relation for stars. Michelson confirmed his estimated stellar diameters in 1920 proving crucial for convincing astronomers unused to his intuitive style. His theory appeared mature form in 1926 as The Internal Constitution of the Stars. This text trained an entire generation of astrophysicists.
During World War I Eddington served as secretary of the Royal Astronomical Society. He received letters from Willem de Sitter regarding Einstein's general relativity first. Internationalist and pacifist views inspired by Quaker beliefs kept him interested in German science despite severed communication lines. He became chief supporter and expositor of relativity in Britain.
Frank Watson Dyson organized two expeditions to observe a solar eclipse in 1919. They measured deflection of light by Sun's gravitational field. Conscription introduced in Britain on the 2nd of March 1916 threatened military service. Cambridge authorities granted exemption based on national interest instead. A tribunal appeal in June claimed conscientious objector status but was not recognized.
Eddington made clear willingness to serve in Friends Ambulance Unit or as harvest labourer during hearings. Sir Frank Dyson supported him at July hearing emphasizing essential role in solar eclipse expedition to Príncipe. Tribunal granted twelve months exemption conditional on continuing astronomy work preparation for Príncipe. War ended before exemption expired.
He traveled to island of Príncipe off west coast of Africa to watch total solar eclipse of the 29th of May 1919. Pictures taken showed stars in Hyades cluster including Kappa Tauri near Sun location. Sky darkened enough to see normally obscured stars during totality. Light rays passing near Sun appeared slightly shifted because gravity curved them according to general relativity theory.
Newtonian gravitation predicted half the shift Einstein proposed. Eddington's observations published next year allegedly confirmed Einstein's theory. Newspapers worldwide reported major story about evidence favoring general relativity over Newtonian model. A 1979 re-analysis validated his results and conclusions using modern measuring equipment.
Eddington investigated instability of Einstein universe while learning of Lemaître's 1927 paper postulating expanding or contracting universe. Hubble's work on recession of spiral nebulae also reached him. He felt cosmological constant played crucial role in evolution from steady state to current expansion. Most investigations focused on constant's significance and characteristics.
During 1920s until death he concentrated on fundamental theory unifying quantum theory, relativity, cosmology and gravitation. He turned increasingly to numerological analysis of dimensionless ratios of fundamental constants. His approach combined several constants to produce numbers close to 10^40, its square or root. Mass of proton and charge of electron formed natural specification for constructing Universe without accident.
Paul Dirac pursued similar line known as Dirac large numbers hypothesis. Fine-structure constant measured near 1/136 initially led him to argue exact value should be 1/136. Later measurements placed closer to 1/137 prompting switch reasoning to add one degree freedom making value exactly 1/137 called Eddington number. Critics started calling him Arthur Adding-one detracting credibility within physics community.
He believed identified algebraic basis termed E-numbers representing Clifford algebra incorporating spacetime into higher-dimensional structure. Predicted number of hydrogen atoms in Universe approximately equaling half total particles protons plus electrons. Book Fundamental Theory published posthumously in 1948 after research remained incomplete before his death.
Eddington wrote in The Nature of the Physical World that stuff of world is mind-stuff. Idealist conclusion derived from current physical theory discarding mechanical theories ether behavior fundamental particles. Materialistic metaphysics outmoded requiring idealistic metaphysics instead since disjunction assumed exhaustive. Second argument based on epistemology stating all objective world knowledge mirrors consciousness structure.
We cannot know objective world nonmentalistic nor intelligibly suppose material properties exist independently. Conceiving dualism entails attributing material properties presupposing observation possible yet whatever observed ultimately content own consciousness consequently nonmaterial. Physics cannot explain consciousness where final leap occurs unclear between physical message and sensation in consciousness.
His two tables paradox represented familiar commonplace table substantial extension colour permanence versus scientific table nothing but minute particles empty space moving great speed. Modern physics assured only one really there wherever there may be. Physicists used borrow raw material from familiar world but new concepts electron quantum potential lack familiar counterpart in common experience.
He argued deeply rooted philosophical harmony between scientific investigation religious mysticism positivist nature relativity quantum mechanics provided room personal religious experience free will. Popular writings made household name Great Britain between wars discussing philosophical implications new physics without claiming science could prove religious propositions.
Eddington's work extended models precipitated dispute with Subrahmanyan Chandrasekhar then student at Cambridge. Chandrasekhar's work presaged discovery black holes seeming absurdly non-physical to Eddington who refused believe purely mathematical derivation had consequences real world. Chandrasekhar narrative portrays Eddington cruel dogmatic though Chandra benefited association obtaining fellowship Royal Society providing comfortable endowment research.
Criticism based partly suspicion purely mathematical derivation insufficient explain daunting physical paradoxes inherent degenerate stars raising irrelevant objections according Thanu Padmanabhan. Eddington died cancer Evelyn Nursing Home Cambridge the 22nd of November 1944 unmarried body cremated Cambridge Crematorium the 27th of November 1944 remains buried grave mother Ascension Parish Burial Ground Cambridge.
Cambridge University North West Cambridge development named Eddington honour him. David Tennant played Eddington television film Einstein and Eddington broadcast United Kingdom Saturday the 22nd of November 2008 BBC2 notable groundbreaking portrayal repressed gay man Paul Eddington relative mentioning misfortune being related foremost physicists world second cousins great-grandsons William Eddington 1755, 1806.
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Common questions
When and where was Arthur Eddington born?
Arthur Stanley Eddington was born on the 28th of December 1882 in Kendal, Westmorland. His family lived at Varzin house located at 42 Walliscote Road in Weston-super-Mare.
What did Arthur Eddington discover about stellar interiors?
Arthur Eddington developed a model showing that radiation pressure prevents stars from collapsing under gravity. He correctly speculated that hydrogen fuses into helium to liberate energy through Einstein's equation.
How did Arthur Eddington confirm Einstein's theory of general relativity?
Arthur Eddington traveled to Príncipe island off the west coast of Africa to observe the total solar eclipse of the 29th of May 1919. His measurements showed light rays bending near the Sun confirmed Einstein's predictions over Newtonian gravitation.
Why did Arthur Eddington receive exemption from military service during World War I?
Cambridge authorities granted Arthur Eddington exemption from conscription introduced on the 2nd of March 1916 based on national interest. The tribunal recognized his essential role in preparing for the solar eclipse expedition to Príncipe.
When and how did Arthur Eddington die?
Arthur Eddington died of cancer at Evelyn Nursing Home Cambridge on the 22nd of November 1944. His body was cremated at Cambridge Crematorium on the 27th of November 1944 with remains buried in Ascension Parish Burial Ground Cambridge.