1838 - Michael Faraday: Lines of force 1838 - Wilhelm Eduard Weber and Carl Friedrich Gauss: Earth's magnetic field 1842-43 - William Thomson, 1st Baron Kelvin and Julius von Mayer: Conservation of energy 1842 - Christian Doppler: Doppler effect 1845 - Michael Faraday: Faraday rotation (interaction of light and magnetic field) 1847 - Hermann von Helmholtz & James Prescott Joule: Conservation of Energy 2 1850-51 - William Thomson, 1st Baron Kelvin & Rudolf Clausius: Second law of thermodynamics 1857-59 - Rudolf Clausius & James Clerk Maxwell: Kinetic theory of gases 1861 - Gustav Kirchhoff: Black body 1861-62 - Maxwell's equations 1863 - Rudolf Clausius: Entropy 1864 - James Clerk Maxwell: A Dynamical Theory of the Electromagnetic Field (electromagnetic radiation) 1867 - James Clerk Maxwell: On the Dynamical Theory of Gases (kinetic theory of gases) 1871-89 - Ludwig Boltzmann & Josiah Willard Gibbs: Statistical mechanics (Boltzmann equation, 1872) 1873 - Maxwell: A Treatise on Electricity and Magnetism 1884 - Boltzmann derives Stefan radiation law 1887 - Michelson–Morley experiment 1887 - Heinrich Rudolf Hertz: Electromagnetic waves 1888 - Johannes Rydberg: Rydberg formula 1889, 1892 - Lorentz-FitzGerald contraction 1893 - Wilhelm Wien: Wien's displacement law for black-body radiation 1895 - Wilhelm Röntgen: X-rays 1896 - Henri Becquerel: Radioactivity 1896 - Pieter Zeeman: Zeeman effect 1897 - J. J. Thomson: Electron discovered 20th century 1900 - Max Planck: Formula for black-body radiation - the quanta solution to radiation ultraviolet catastrophe 1904 - J. J. Thomson's plum pudding model of the atom 1904 1905 - Albert Einstein: Special relativity, proposes light quantum (which is named the photon by GN Lewis in 1926) to explain the photoelectric effect, Brownian motion, Mass–energy equivalence 1908 - Hermann Minkowski: Minkowski space 1911 - Ernest Rutherford: Discovery of the atomic nucleus (Rutherford model) 1911 - Kamerlingh Onnes: Superconductivity 1913 - Niels Bohr: Bohr model of the atom 1915 - Albert Einstein: General relativity 1916 - Schwarzschild metric modeling gravity outside a large sphere 1919 - Arthur Eddington:Light bending confirmed - evidence for general relativity 1919-1926 - Kaluza–Klein theory proposing unification of gravity and electromagnetism 1922 - Alexander Friedmann proposes expanding universe 1922-37 - Friedmann–Lemaître–Robertson–Walker metric cosmological model 1923 - Stern–Gerlach experiment 1923 - Edwin Hubble: Galaxies discovered 1923 - Arthur Compton: Particle nature of photons confirmed by observation of photon momentum 1924 - Bose–Einstein statistics 1924 - Louis de Broglie: De Broglie wave 1925 - Werner Heisenberg: Matrix mechanics 1925-27