1919 in science

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The year 1919 in science and technology involved some significant events, listed below.

Astronomy

  • April – George Ellery Hale and collaborators publish their discovery that the magnetic polarity of sunspot pairs reverses on an 11-year solar cycle and that the polarity varies by hemisphere, which becomes known as Hale's law.{{cite journal|last1=Hale|first1=George E.|last2=Ellerman|first2=Ferdinand|last3=Nicholson|first3=S. B.|last4=Joy|first4=A. H.|title=The Magnetic Polarity of Sun-Spots|journal=The Astrophysical Journal|date=April 1919|volume=49|pages=153|doi=10.1086/142452|bibcode=1919ApJ....49..153H|doi-access=free}}{{cite web|title=Hale's Sunspot Polarity Law|last1=Charbonneau|first1=P.|last2=White|first2=O. R.|date=1995-04-18|publisher=High Altitude Observatory|url=https://www2.hao.ucar.edu/Education/Sun/hales-sunspot-polarity-law|website=www2.hao.ucar.edu|access-date=2021-08-20|archive-date=2021-08-19|archive-url=https://web.archive.org/web/20210819182851/https://www2.hao.ucar.edu/Education/Sun/hales-sunspot-polarity-law|url-status=live}}
  • The International Astronomical Union is established in Paris.

Chemistry

History of science

Mathematics

Medicine

Physics

  • May 29 – Einstein's theory of general relativity is tested by Arthur Eddington's observation of the "bending of light" during the total solar eclipse on this day observed in Principe, and by Andrew Crommelin in Sobral, Ceará, Brazil (confirmed November 6).{{cite journal|last=Dyson|first=F. W.|author2=Eddington, A. S.|author3=Davidson, C. R.|year=1920|title=A Determination of the Deflection of Light by the Sun's Gravitational Field, from Observations Made at the Solar eclipse of May 29, 1919|journal=Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences|volume=220|issue=571–581|pages=291–333|bibcode=1920RSPTA.220..291D|doi=10.1098/rsta.1920.0009|url=https://zenodo.org/record/1432106|doi-access=free}} Paper received October 30, read November 6, published April 27, 1920.
  • Arnold Sommerfeld and Walther Kossel publish their displacement law.Verhandlungen der Deutschen Physikalischen Gesellschaft.; {{cite book|last1=Mehra|first1=Jagdish|first2=Helmut|last2=Rechenberg|author-link1=Jagdish Mehra |author-link2=Helmut Rechenberg |title=The Historical Development of Quantum Theory. Vol. 1, Part 1: The Quantum Theory of Planck, Einstein, Bohr and Sommerfeld 1900–1925: its Foundation and the Rise of Its Difficulties|publisher=Springer|year=1982|isbn=978-0-387-95174-4|page=330}}
  • James Jeans discovers that the dynamical constants of motion determine the distribution function for a system of particles.
  • Betz's law is published by German physicist Albert Betz, indicating the maximum power that can be extracted from the wind, independent of the design of a wind turbine in open flow.

Psychology

  • In Berlin Dr Magnus Hirschfeld and Arthur Kronfeld found the Institut für Sexualwissenschaft.[http://www.hirschfeld.in-berlin.de/aus_inst_en.html hirschfeld.in-berlin.de, The first Institute for Sexual Science.][http://www.stonewallsociety.com/famouspeople/magnus.htm Famous GLBT & GLBTI People – Dr. Magnus Hirschfeld] stonewallsociety.[https://books.google.com/books?id=Tex-BuFgji0C&pg=PA16 Grossmann, Atina. Reforming Sex. Oxford University Press, 1995.][http://www.sgipt.org/gesch/kronf/kronf_e.htm In Memory of Arthur Kronfeld.]

Technology

Awards

Births

Deaths

References

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Category:20th century in science

Category:1910s in science