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1936 Eugene Wigner develops the theory of neutron absorption by atomic nuclei; 1936 Hermann Arthur Jahn and Edward Teller present their systematic study of the symmetry types for which the Jahn–Teller effect is expected [8] 1937 Carl Anderson proves experimentally the existence of the pion predicted by Yukawa's theory.
The current theoretical model of the atom involves a dense nucleus surrounded by a probabilistic "cloud" of electrons. Atomic theory is the scientific theory that matter is composed of particles called atoms. The definition of the word "atom" has changed over the years in response to scientific discoveries.
1801 – Thomas Young: Wave theory of light; 1801 - Johann Wilhelm Ritter: Ultraviolet light; 1803 – John Dalton: Atomic theory of matter [citation needed] 1806 – Thomas Young: Kinetic energy; 1814 – Augustin-Jean Fresnel: Wave theory of light, optical interference
1963 – Eugene P. Wigner lays the foundation for the theory of symmetries in quantum mechanics as well as for basic research into the structure of the atomic nucleus; makes important "contributions to the theory of the atomic nucleus and the elementary particles, particularly through the discovery and application of fundamental symmetry ...
260 BC: Aristarchus of Samos proposes a basic heliocentric model of the universe. [61] 200 BC: Apollonius of Perga discovers Apollonius's theorem. 200 BC: Apollonius of Perga assigns equations to curves. 200 BC: Apollonius of Perga develops epicycles. While an incorrect model, it was a precursor to the development of Fourier series.
Progression of atomic theory. Democritus, the originator of atomic theory, held that everything is composed of atoms that are indestructible. His claim that atoms are indestructible is not the reason it is superseded—as it was later scientists who identified the concept of atoms with particles, which later science showed are destructible.
First to explain the effects of Brownian motion as caused by the kinetic energy (i.e., movement) of atoms, which was subsequently, experimentally verified by Jean Baptiste Perrin, thereby settling the century-long dispute about the validity of John Dalton's atomic theory. 1905: Albert Einstein: Published his Special Theory of Relativity. 1905
The Bohr–Sommerfeld model (also known as the Sommerfeld model or Bohr–Sommerfeld theory) was an extension of the Bohr model to allow elliptical orbits of electrons around an atomic nucleus. Bohr–Sommerfeld theory is named after Danish physicist Niels Bohr and German physicist Arnold Sommerfeld. Sommerfeld showed that, if electronic orbits ...