NASA's Cosmicopia -- History -- 1900-1949

1900: Paul Villard described gamma rays
1900: Max Planck put forward his quantum theory
1901: First Nobel Prize awarded in physics (to Roentgen)
1905: Albert Einstien published his theory of Special Relativity and introduced the idea of discrete packets of energy, later called "photons"
1908: George Hale demonstrated that sunspots are produced by strong magnetic fields
1909: The amount of charge in an electron was determined by Robert Millikan
1911: Ernest Rutherford discovered the atomic nucleus
1911: Charles Wilson invented a cloud chamber, which was used to detect alpha and beta particles and electrons
1912: Cosmic ray research began in 1912 when Victor Hess, of the Vienna University, and 2 assistants flew in a balloon to an altitude of about 16,000 ft. They discovered evidence of a very penetrating radiation (cosmic rays) coming from outside our atmosphere. In 1936, Hess was awarded the Nobel prize for this discovery.
1913: Niels Bohr proposed that atoms contain orbital shells of electrons
1914: Ernest Rutherford discovered the proton
1916: Albert Einstein published his General Theory of Relativity
1920: Harlow Shapley and Heber Curtis: The Great Debate over the scale and structure of the universe
1920: Ernest Rutherford proposed the existence of the neutron
1920: Harkins and Eddington found that the fusion of hydrogen could be the energy source of stars. Image of Sagittarius star cloud is courtesy of NASA/ARC.
1922: Russian physicist/mathematician Alexander Freedmann predicted that the universe is expanding
1925: Robert Millikan introduced the term "cosmic rays"
March 16, 1926: Robert Goddard, for whom the NASA Goddard Space Flight Center is named, fired the first liquid fuel rocket.
1928: Paul Dirac predicted that for every particle, there is a corresponding anti-particle that is exactly like the particle but with opposite charge = antimatter
1929: Using a newly invented cloud chamber, Dimitry Skobelzyn observed the first ghostly tracks left by cosmic rays
1929: Walter Bothe and Werner Kolhorster verified that the Skobelzyn's cloud chamber tracks are curved, showing that cosmic rays are charged particles
1930: Ernest Lawrence invented the cyclotron, the first particle accelerator, for which he received the Nobel Prize in 1939
1930: Wolfgang Pauli proposed the existence of the neutrino
1930: Invention of the coronograph by Bernard Lyot
1932: James Chadwick discovered the neutron
1932: Carl Anderson discovered antimatter (positrons) in his cloud chamber. He shared the 1936 Nobel Prize with Victor Hess for his work.
1932: John Cockroft and Ernest Walton used a particle accelerator to split the atom
1932: Dr. Robert A. Millikan of Caltech, winner of the 1923 Nobel prize in physics, completed a series of tests on the intensity of cosmic rays at various altitudes in a Condor bomber from March Field, Calif.
1935: Explorer II, a 113,000 cubic foot rubberized helium balloon ascended to the official record of 22,066 m while collecting atmospheric, cosmic ray, and other data.
1935: Hideki Yukawa predicted the existence of mesons, for which he won the 1949 Nobel Prize
1937: Seth Neddermeyer and Carl Anderson discovered the muon (for mu meson) in cosmic rays
1937: First artificial element, technetium, was created
1938: Otto Hahn and Fritz Strassmann discovered nuclear fission
1938: Pierre Auger discovered "extensive air showers", showers of secondary subatomic particles caused by the collision of high energy cosmic rays with air molecules
1940: A Beechcraft AD-17 biplane was flown to an altitude of 21,050 ft over the Antarctic to measure cosmic rays for the U.S. Antarctic Expedition.
1947: Pions (for pi mesons) were discovered by Cecil Powell.
1947: Physicist Martin Pomerantz announced at Swarthmore College that he had sent a flight of four free balloons, carrying cosmic ray equipment, to a record height of at least 127,000 feet over the Antarctic.
1948: Bethe and Gamow explained nucleosynthesis in a hot big bang.
1949: Enrico Fermi proposed that cosmic ray protons are accelerated by bouncing off moving magnetic clouds in space, as in the shock waves around a supernova

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The History of Cosmic Ray Studies

1900 - 1949