Solar eclipse of 1919

Solar eclipse of 1919
Name	Solar eclipse of 1919
Date	29 May 1919
Type	Total
Magnitude	1.034
Location	Atlantic Ocean, South America, Africa
Greatest	09:33 GMT

Contents

Solar eclipse of 1919 The total solar eclipse of 29 May 1919 produced observations that played a pivotal role in 20th‑century physics, linking experimental astronomy with theoretical physics through expeditions that connected Royal Observatory, Greenwich, Cambridge University, Cambridge, Princeton University, and Cambridge, England. The event prompted coordinated efforts involving figures from United Kingdom, Brazil, Sierra Leone, United States, and France and influenced discourse among proponents of Albert Einstein, Arthur Eddington, G. B. Airy, Max Planck, and Hermann Weyl.

Background and context

The eclipse occurred against a backdrop of recent developments in Albert Einstein's General relativity and debates at institutions such as University of Berlin, University of Göttingen, University of Cambridge, and Royal Society. Prior theoretical work by Isaac Newton's successors and researchers associated with Karl Schwarzschild, Hendrik Lorentz, Paul Ehrenfest, and Hermann Minkowski set the stage for experimental tests in observational programs at observatories like Royal Observatory, Greenwich, Cape Observatory, Lick Observatory, and Yerkes Observatory. Political aftermath of World War I influenced access and collaboration among scientists from United Kingdom, Germany, France, and United States during planning that involved figures connected to British Astronomical Association, Royal Astronomical Society, Royal Navy, and colonial administrations in Sierra Leone and Brazil.

Two major expeditions were organized: one led by Arthur Eddington departing from Cambridge University to São Tomé and Príncipe and Principe (island), and another led by Andrew Crommelin and Charles Davidson from Royal Observatory, Greenwich to Sobral, Ceará in Brazil. Eddington's team included associates connected to Royal Astronomical Society, H. H. Turner, Frank Dyson, and members with ties to University of Cambridge and St John's College, Cambridge, while the Sobral party coordinated with local authorities in Brazil and personnel linked to Observatório Nacional (Brazil). Instruments transported from institutions such as Royal Greenwich Observatory, Cambridge Observatory, Oxford University, and observatories in Paris and London included astrographs, photographic plates, and measuring equipment manufactured by firms associated with Zeiss and Cooke.

Teams used comparative astrometry to measure apparent positions of stars near the eclipsed Sun on photographic plates taken with astrographs and telescopes borrowed from Royal Observatory, Greenwich, Cambridge Observatory, Lick Observatory, and instrument makers like Zeiss Ikon. Reduction techniques involved reference catalogues compiled at Harvard College Observatory and Yerkes Observatory, and analysts applied error analysis methods familiar to researchers at University of Cambridge, Royal Society, University of Oxford, and Princeton University. Eddington reported deflections consistent with predictions from Albert Einstein's field equations, while the Sobral team produced measurements from independent instruments that supported a larger sample of plates and calibrations associated with Frank Dyson and Arthur Eddington's data processing.

Results announced at meetings of the Royal Society and published in proceedings associated with Philosophical Transactions of the Royal Society provided empirical support for Albert Einstein's General relativity over Newtonian gravity as formulated in classical works by Isaac Newton and discussed by theorists including Hendrik Lorentz, Max Planck, Erwin Schrödinger, and Hermann Weyl. The Eddington and Sobral measurements of stellar deflection were interpreted by proponents at University of Cambridge, Royal Observatory, Greenwich, Institute for Advanced Study, and University of Berlin as a confirmation of the predicted 1.75 arcsecond deflection near the solar limb, influencing acceptance among members of International Astronomical Union, Royal Astronomical Society, and scientific journals such as Nature.

Debate emerged involving scientists connected to Royal Society, Oxford University, Cambridge University, Harvard College Observatory, and critics from circles tied to Eddington's pacifist politics and affiliations with Quakers, leading to disputes over data selection, plate quality, and statistical treatment. Later re-analyses by researchers at University of Cambridge, Royal Greenwich Observatory, Harvard-Smithsonian Center for Astrophysics, National Observatory of Brazil, and independent statisticians revisited archives held at Royal Astronomical Society, Cambridge University Library, and Observatório Nacional (Brazil), prompting reassessments of measurement uncertainties and corroboration by subsequent eclipse expeditions and techniques developed at Palomar Observatory, Mount Wilson Observatory, Very Large Telescope, and radio interferometry groups associated with NRAO.

The 1919 expeditions became emblematic in biographies of Albert Einstein and Arthur Eddington, featured in press coverage by newspapers like The Times (London), The New York Times, and magazines associated with Time (magazine), influencing popular reception in United Kingdom, United States, Germany, and Brazil. The episode affected institutional narratives at Royal Society, Royal Astronomical Society, University of Cambridge, and Princeton University and entered cultural works referencing Einstein in biographies, documentaries, museum exhibits at Science Museum, London, Museum of the History of Science, Oxford, and educational materials used by museums such as Smithsonian Institution. The eclipse and its scientific aftermath remain referenced in histories produced by scholars at University of Cambridge, Princeton University Press, Oxford University Press, and articles in Nature and Science.

Category:Solar eclipses Category:1919 in science Category:Albert Einstein