1924 in science

Astronomy and space exploration

• November 23 – Edwin Hubble announces his discovery that Andromeda, previously believed to be a nebula, is actually another galaxy, and that the Milky Way is only one of many such galaxies in the universe.
• The Einstein Tower near Potsdam, Germany, designed by Erich Mendelsohn, becomes operational as an astrophysical observatory.
• Mount Stromlo Observatory near Canberra, Australia, is established as the Commonwealth Solar Observatory.
• 1056 Azalea is discovered.

  Biology

• The term "ectogenesis" is coined by British scientist J.B.S. Haldane to describe the growth of mammalian embryos in artificial environments.

  Biochemistry

• The first inactive tetanus toxoid is discovered and produced.

  History of science and technology

• December 17 – Dismantling of James Watt's workshop for display in the Science Museum, London, commences.

  Mathematics

• Stefan Banach and Alfred Tarski publish the Banach–Tarski paradox.
• David Hilbert proposes Hilbert's paradox of the Grand Hotel.

  Medicine

• German physiologist and psychiatrist Hans Berger records the first human electroencephalogram.

  Paleontology

• The first specimen of Australopithecus africanus, the fossil skull of the "Taung Child", is identified in South Africa.

  Physics

• S. N. Bose and Albert Einstein publish papers in Zeitschrift für Physik applying Bose–Einstein statistics to light quanta and to atomic models and predicting existence of the Bose–Einstein condensate.
• E. C. Stoner publishes a paper pointing out that for a given value of the principal quantum number, the number of energy levels of a single electron in the alkali metal spectra in an external magnetic field, where all degenerate energy levels are separated, is equal to the number of electrons in the closed shell of the rare gases for the same value of n. This leads to discovery of the Pauli exclusion principle.
• Louis de Broglie introduces the wave-model of atomic structure, based on the ideas of wave–particle duality.
• End – Wolfgang Pauli first proposes his exclusion rule in a letter.

  Technology

• February 5 – Hourly time signals from Royal Greenwich Observatory are broadcast for the first time.
• February – John Logie Baird sends rudimentary television pictures over a short distance.
• Václav Holek designs the ZB vz. 26 light machine gun for Zbrojovka Brno.
• The earth inductor compass is developed by Morris Titterington at the Pioneer Instrument Company in Brooklyn, New York.

  Awards

• Nobel Prizes
• * Physics: Karl Manne Georg Siegbahn
• * Medicine: Willem Einthoven

  Births

• February – Li Xintian, Chinese neuropsychologist
• February 21 – Thelma Estrin, American computer scientist and biomedical engineer
• March 11 – Franco Basaglia, Italian psychiatrist
• March 23 – Bjørn G. Andersen, Norwegian quaternary geologist and glaciologist
• June 24 – James W. Black, Scottish pharmacologist
• July 8 – Robert M. Chanock, American pediatrician and virologist
• August 1 – John Clive Ward, English-born physicist working in quantum electrodynamics
• September 10 – Elizabeth Killick, English naval electronics engineer
• September 22 – Laurel van der Wal, American aeronautical engineer
• November 9 – Don Beaven, New Zealand medical researcher in the area of diabetes treatment and prevention
• November 20 – Benoît Mandelbrot, Polish-born French American mathematician, originator of fractal geometry
• December 30 – Yvonne Brill, Canadian scientist best known for her work developing rocket and jet propulsion technologies

  Deaths

• February 11 – Jacques Loeb, German-born physiologist
• March 22 – Sir William Macewen, Scottish surgeon
• April 4 – Arnold Pick, Czech neurologist
• April 24 – G. Stanley Hall, American psychologist
• September 24 – Alexandre Lacassagne, French forensic scientist
• October 1 – John Edward Campbell, British mathematician
• December 27 – Agda Meyerson, Swedish nurse and healthcare profession activist