---
title: "Timeline of scientific discoveries"
chunk: 6/7
source: "https://en.wikipedia.org/wiki/Timeline_of_scientific_discoveries"
category: "reference"
tags: "science, encyclopedia"
date_saved: "2026-05-05T03:28:31.534973+00:00"
instance: "kb-cron"
---

== 1850–1899 ==
1856: Robert Forester Mushet develops a process for the decarbonisation, and re-carbonisation of iron, through the addition of a calculated quantity of spiegeleisen, to produce cheap, consistently high quality steel.
1858: Rudolf Virchow: cells can only arise from pre-existing cells.
1859: Charles Darwin and Alfred Wallace: Theory of evolution by natural selection.
1861: Louis Pasteur: Germ theory.
1861: John Tyndall:  Experiments in Radiant Energy that reinforced the Greenhouse effect.
1864: James Clerk Maxwell: Theory of electromagnetism.
1865: Gregor Mendel: Mendel's laws of inheritance, basis for genetics.
1865: Rudolf Clausius: Definition of entropy.
1868: Robert Forester Mushet discovers that alloying steel with tungsten produces a harder, more durable alloy.
1869: Dmitri Mendeleev: Periodic table.
1871: Lord Rayleigh: Diffuse sky radiation (Rayleigh scattering) explains why sky appears blue.
1873: Johannes Diderik van der Waals: was one of the first to postulate an intermolecular force: the van der Waals force.
1873: Frederick Guthrie discovers thermionic emission.
1873: Willoughby Smith discovers photoconductivity.
1875: William Crookes invented the Crookes tube and studied cathode rays.
1876: Josiah Willard Gibbs founded chemical thermodynamics, the phase rule.
1877: Ludwig Boltzmann: Statistical definition of entropy.
1880s: John Hopkinson develops three-phase electrical supplies, mathematically proves how multiple AC dynamos can be connected in parallel, improves permanent magnets, and dynamo efficiency, by the addition of tungsten, and describes how temperature effects magnetism (Hopkinson effect).
1880: Pierre Curie and Jacques Curie: Piezoelectricity.
1884: Jacobus Henricus van 't Hoff: discovered the laws of chemical dynamics and osmotic pressure in solutions (in his work "Études de dynamique chimique").
1887: Albert A. Michelson and Edward W. Morley: Michelson–Morley experiment which showed a lack of evidence for the aether.
1888: Friedrich Reinitzer discovers liquid crystals.
1892: Dmitri Ivanovsky discovers viruses.
1895: Wilhelm Conrad Röntgen discovers x-rays.
1896: Henri Becquerel discovers radioactivity
1896: Svante Arrhenius derives the basic principles of the greenhouse effect
1897: J.J. Thomson discovers the electron in cathode rays
1898: Martinus Beijerinck: concluded that a virus is infectious—replicating in the host—and thus not a mere toxin, and gave it the name "virus"
1898: J.J. Thomson proposed the plum pudding model of an atom
1898: Marie Curie discovered radium and polonium
1898: J. J. O'Donnell discovers and documents the order-of-sequence for the sound of an approaching tornado

== 1900–1949 ==
1900: Max Planck: explains the emission spectrum of a black body
1905: Albert Einstein: theory of special relativity, explanation of Brownian motion, and photoelectric effect
1906: Walther Nernst: Third law of thermodynamics
1907: Alfred Bertheim: Arsphenamine, the first modern chemotherapeutic agent
1909: Fritz Haber: Haber Process for industrial production of ammonia
1909: Robert Andrews Millikan: conducts the oil drop experiment and determines the charge on an electron
1910: Williamina Fleming: the first white dwarf, 40 Eridani B
1911: Ernest Rutherford: Atomic nucleus
1911: Heike Kamerlingh Onnes: Superconductivity
1912: Alfred Wegener: Continental drift
1912: Max von Laue: x-ray diffraction
1912: Vesto Slipher: galactic redshifts
1912: Henrietta Swan Leavitt: Cepheid variable period-luminosity relation
1913: Henry Moseley: defined atomic number
1913: Niels Bohr: Model of the atom
1915: Albert Einstein: theory of general relativity – also David Hilbert
1915: Karl Schwarzschild: discovery of the Schwarzschild radius leading to the identification of black holes
1918: Emmy Noether: Noether's theorem – conditions under which the conservation laws are valid
1920: Arthur Eddington: Stellar nucleosynthesis
1922: Frederick Banting, Charles Best, James Collip, John Macleod: isolation and production of insulin to control diabetes
1924: Wolfgang Pauli: quantum Pauli exclusion principle
1924: Edwin Hubble: the discovery that the Milky Way is just one of many galaxies
1925: Erwin Schrödinger: Schrödinger equation (quantum mechanics)
1925: Cecilia Payne-Gaposchkin: Discovery of the composition of the Sun and that hydrogen is the most abundant element in the Universe
1927: Werner Heisenberg: Uncertainty principle (quantum mechanics)
1927: Georges Lemaître: Theory of the Big Bang
1928: Paul Dirac: Dirac equation (quantum mechanics)
1929: Edwin Hubble: Hubble's law of the expanding universe
1929: Alexander Fleming: Penicillin, the first beta-lactam antibiotic
1929: Lars Onsager's reciprocal relations, a potential fourth law of thermodynamics
1930: Subrahmanyan Chandrasekhar discovers his eponymous limit of the maximum mass of a white dwarf star
1931: Kurt Gödel: incompleteness theorems prove formal axiomatic systems are incomplete
1932: James Chadwick: Discovery of the neutron
1932: Karl Guthe Jansky discovers the first astronomical radio source, Sagittarius A
1932: Ernest Walton and John Cockcroft: Nuclear fission by proton bombardment
1934: Enrico Fermi: Nuclear fission by neutron irradiation
1934: Clive McCay: Calorie restriction extends the maximum lifespan of another species
1938: Otto Hahn, Lise Meitner and Fritz Strassmann: Nuclear fission of heavy nuclei
1938: Isidor Rabi: Nuclear magnetic resonance
1943: Oswald Avery proves that DNA is the genetic material of the chromosome
1945: Howard Florey Mass production of penicillin
1947: William Shockley, John Bardeen and Walter Brattain invent the first transistor
1948: Claude Elwood Shannon: 'A mathematical theory of communication' a seminal paper in Information theory.
1948: Richard Feynman, Julian Schwinger, Sin-Itiro Tomonaga and Freeman Dyson: Quantum electrodynamics