The History of Cosmic Ray Studies
1900 - 1949
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- Paul Villard described gamma rays
- Max Planck put forward his quantum theory
- First Nobel Prize awarded in physics (to Roentgen)
- Albert Einstien published his theory of Special Relativity and
introduced the idea of discrete packets of energy, later called
- George Hale demonstrated that sunspots are produced by strong
- The amount of charge in an electron was determined by Robert
- Ernest Rutherford discovered the atomic nucleus
- Charles Wilson invented a cloud chamber, which was used to detect
alpha and beta particles and electrons
- 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.
- Niels Bohr proposed that atoms contain orbital shells of electrons
- Ernest Rutherford discovered the proton
- Albert Einstein published his General Theory of Relativity
- Harlow Shapley and Heber Curtis: The Great Debate over the scale and structure of the universe
- Ernest Rutherford proposed the existence of the neutron
- 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.
- Russian physicist/mathematician Alexander Freedmann predicted that the universe is expanding
- 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.
- Paul Dirac predicted that for every particle, there is a
corresponding anti-particle that is exactly like the particle but with
opposite charge = antimatter
- Using a newly invented cloud chamber, Dimitry Skobelzyn observed
the first ghostly tracks left by cosmic rays
- Walter Bothe and Werner Kolhorster verified that the Skobelzyn's
cloud chamber tracks are curved, showing that cosmic rays are charged
- Ernest Lawrence invented the cyclotron, the first particle
accelerator, for which he received the Nobel Prize in 1939
- Wolfgang Pauli proposed the existence of the neutrino
- Invention of the coronograph by Bernard Lyot
- James Chadwick discovered the neutron
- Carl Anderson discovered antimatter (positrons) in his cloud
chamber. He shared the 1936 Nobel Prize with Victor Hess for his
- John Cockroft and Ernest Walton used a particle accelerator to
split the atom
- 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.
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.
- Hideki Yukawa predicted the existence of mesons, for which he won
the 1949 Nobel Prize
- Seth Neddermeyer and Carl Anderson discovered the muon (for mu
meson) in cosmic rays
- First artificial element, technetium, was created
- Otto Hahn and Fritz Strassmann discovered nuclear fission
- Pierre Auger discovered "extensive air showers", showers of
secondary subatomic particles caused by the collision of high energy
cosmic rays with air molecules
- 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.
- Pions (for pi mesons) were discovered by Cecil Powell.
- 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.
- Bethe and Gamow explained nucleosynthesis in a hot big bang.
- 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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