Physics Timeline

Physics Timeline

Ancient Greeks

425 BC	Democritus proposes that all matter is made of small indivisible particles that he calls "atoms."
280 BC	Aristarchus of Samos determines the relative distances of the sun and the moon from the earth. He also determines the relative sizes of the sun, the moon and the earth. These considerations lead him to propose that the earth revolves around the sun.
240 BC	Archimedes discovers his principle of buoyancy (Archimedes' Principle).
235 BC	Eratosthenes develops a method to measure the circumference of the earth.
130 BC	Hipparchus estimates the size of moon from the parallax of an eclipse.
130	Ptolemy develops his a theory of the motion of the heavenly bodies. According to his theory, the earth is at the center of the universe and the sun and known planets revolve around it.

Pre-Galilean Physics

1269	Petrus de Maricourt conducts experiments with magnets and magnetic compasses.
1514	Nicolaus Copernicus develops his heliocentric theory. He publishes it in 1543, a few days before his death.

Classical Physics

1592	Galileo Galilei invents the thermometer.
1600	William Gilbert publishes De Magnete which starts the modern treatment of magnetism. He also shows that the earth is a magnet.
1604	Galileo Galilei proves that falling bodies are accelerated towards the ground at a constant rate. He also shows that the distance for a falling object increases as the square of the time.
1609	Johannes Kepler publishes his First and Second laws of planetary motion in a book entitled Astronomia Nova.
1609	Galileo Galilei builds a telescope after hearing of its invention.
1613	Galileo Galilei introduces his principle of inertia.
1619	Johannes Kepler publishes his Third law of planetary motion.
1621	Willebrord van Roijen Snell introduces the law of refraction.
1638	Galileo introduces the concept of the relativity of motion in his Two New Sciences.
1651	Blaise Pascal shows that pressure applied at one point in a liquid is transmitted unchanged to all points in the liquid (Pascal's Principle).
1662	Robert Boyle, while experimenting with gases, shows that if a fixed amount of a gas is kept at a constant temperature, the pressure and the volume of the gas follow a simple mathematical relationship.
1665-1966	Isaac Newton begins his work on the motion of bodies. He also completes his theory of colors, develops the main ideas on the calculus, and his law of gravitation.
1668	Isaac Newton designs and builds a reflecting telescope.
1672	Isaac Newton, in a letter to the Royal Society, describes his experiments explaining the nature of color. This letter became Newton's first published scientific paper.
1676	Robert Hooke proposes his law relating the elongation of a spring to the force applied to produce that elongation.
1714	Gabriel Fahrenheit introduces the mercury thermometer and his new scale of temperature.
1738	Daniel Bernoulli develops the foundations of hydrodynamics.
1742	Anders Celsius proposes a new temperature scale.
1838	Friedrich Bessel first observes the parallax of a star with the aid of a telescope.
1747	Benjamin Franklin conducts experiments that show that one type of electrification could be neutralized by the other type. This indicated to him that the two types of electricity were not just different; they were opposites and calls one type positive and the other negative.
1848	William Thomson, Lord Kelvin, devises what is now known as the absolute temperature scale or Kelvin scale.
1766	Joseph Priestley proposes that the force between electric charges follows an inverse square law.
1777	Charles de Coulomb invents a torsion balance to measure the force between electrically charged objects (Coulomb's law).
1787	Jacques-Alexander Charles discovers the relationship between the change in volume of a gas with temperature. He fails to publish his discovery.
1798	Henry Cavendish adapts the torsion balance invented by Coulomb to measure the gravitational constant.
1798	Benjamin Thompson, Count Rumford, introduces the idea that the heat was a form of motion.
1800	Alessandro Volta invents the battery.
1802	Thomas Young, in a landmark experiment, demonstrates that light is a wave phenomenon.
1802	Gian Domenico Romagnosi proposes in a newspaper article that an electric current affects a magnetic current. His discovery is largely ignored. Oersted, a better known scientist, would discover the same phenomenon in 1819.
1804	Joseph Louis Gay-Lussac, without knowledge of Charles' work of 1787, discovers the relationship between the expansion of a gas at constant pressure and the temperature. This discovery is known as Gay-Lussac's law.
1808	John Dalton develops his atomic theory.
1814	Joseph von Fraunhofer invents the spectroscope and with it he observes the absorption lines in the sun's spectrum two years later.
1819	Hans Christian Oersted discovers that an electric current deflects a magnetic compass. His discovery, published in a scientific journal, gets noticed.
1820	André Ampère gives mathematical form to Oersted's discovery. In modern language, Ampère's law is stated as follows: an electric current creates a magnetic field.
1820	Biot and Savart propose a force law between an electric current and a magnetic field.
1822	André Ampère shows that two wires carrying electric currents attract each other.
1827	Georg Ohm shows that current and voltage are related by a very simple relationship, known today as Ohm's law.
1831	Michael Faraday showed experimentally that a changing magnetic field produces an electric current (Faraday's law).
1842	Christian Doppler proposes his Doppler Effect for sound and light waves.
1843	James Joule measures the electrical equivalent of heat.
1846	Gustav Kirchhoff proposes his rules of electrical circuits (Kirchoff's rules).
1850	Rudolf Gottlieb, known as Clausius, states the second law of thermodynamics.
1851	Armand Fizeau measures the velocity of light in a moving medium.
1868	James Clerk Maxwell proposes the electromagnetic nature of light and suggests that electromagnetic waves exist and are observed as light.
1869	Dmitri Mendeleyev proposes his periodic table of the chemical elements.
1873	Johannes van der Waals develops his theory of intermolecular forces in fluids.
1887	Heinrich Hertz generates electromagnetic waves in his laboratory.

Modern Physics

1887	Albert Michelson and E.W. Morley, in a landmark experiment, determine the absence of the ether, a substance postulated to fill all space.
1895	Wilhelm Roentgen discovers X-rays.
1890	James Prescott Joule measures the mechanical equivalent of heat.
1897	J.J. Thomson determines the charge to mass ratio of the electron.
1898	Pierre and Marie Curie discover the radioactive elements radium and polonium.
1898	Ernest Rutherford discovers alpha and beta radiation.
1900	Max Planck introduces the concept of quanta in black body radiation and Planck's constant.
1905	Albert Einstein explains Brownian motion.
1905	Albert Einstein explains the photoelectric effect.
1905	Albert Einstein publishes his special theory of relativity.
1905	Albert Einstein postulates the equivalence of mass and energy.
1906	Albert Einstein proposes quantum explanation of the specific heat laws for solids.
1909	Robert Millikan measures the charge on the electron.
1911	Heike Kamerlingh Onnes introduces his theory of superconductivity.
1911	Ernest Rutherford discovers the nucleus of the atom.
1913	Niels Bohr proposes his quantum theory of atomic orbits.
1915	Albert Einstein publishes his general theory of relativity.
1916	Karl Schwarzschild calculates the critical radius of curvature of space-time around a collapsing star at which light cannot escape.
1917	Albert Einstein presents his theory of stimulated emission, the foundation for the laser.
1918	Emmy Nöther proposes the mathematical relationships between symmetry and conservation laws of physics.
1923	Louis de Broglie predicts the wave nature of particles.
1925	Werner Heisenberrg develops matrix mechanics, the first quantum mechanical theory.
1926	Erwin Schrödinger develops wave mechanics, an alternate quantum mechanical theory.
1926	Werner Heisenberg proposes the uncertainty principle.
1927	Niels Bohr proposes the principle of complementarity.
1927	Niels Bohr develops the Copenhagen interpretation of quantum mechanics.
1930	Ernest Orlando Lawrence and M. Stanley Livingston invent the cyclotron.
1932	James Chadwick identifies the neutron.
1932	Werner Heisenberg proposes that the nucleus of an atom is composed of protons and neutrons.
1942	Enrico Fermi obtains the first self sustaining fission reaction.
1948	Shin'ichiro Tomonaga, Julian Schwinger, and Richard Feynman develop quantum electrodynamics or QED.
1948	John Bardeen, Walter Brattain, and William Shockley invent the transistor.
1953	Charles Townes invents the maser.
1954	C.N. Yang and Robert L. Mills propose a non-abelian gauge theory.
1956	Murray Gell-Mann and Kazuhiko Nishijima introduce the strangeness quantum number.
1957	John Bardeen, Leon Cooper, and John R. Schrieffer propose their BCS theory of superconductivity.
1961	Sheldon Glashow introduces the neutral intermediate vector boson of electroweak interactions.
1961	Murray Gell-Mann and Yuval Ne'eman independendently discover the SU(3) octet symmetry of hadrons.
1964	Peter Higgs, Robert Brout, and F. Englert introduce the Higgs mechanism of symmetry breaking.
1964	Murray Gell-Mann and George Zweig independently propose the quark theory of hadrons.
1965	John Stewart Bell states and proves a powerful theorem (Bell's theorem), which gives the theoretical limits on the correlations between the results of simultaneous measurements done on two separated particles. The limits on these correlations are given by Bell in the form of an inequality.
1965	Arno Penzias and Robert Wilson measure the cosmic background radiation.
1967	Steven Weinberg and Abdus Salam independently propose the electroweak unification which is based on significant contributions by Sheldon Glashaw. The three would later share the Nobel Prize in physics for their theory.
1974	Howard Georgi and Sheldon Glashow propose the SU(5) as a Grand Unified Theory and predict decay of the proton.
1977	A Fermilab team detects the bottom quark
1981	Michael Green and John Schwarz propose what becomes known as Type I superstring theory.
1981	Gerd Binnig and Heinrich Rohrer invent the scanning tunneling microscope.
1982	Alain Aspect performs an experiment that is considered to confirm the non-local aspects of quantum mechanics.
1983	Carlo Rubbia leads a team that detects the W and Z bosons at CERN.
1994	A Fermilab team detects the top quark.
2000	Tantalizing hints of the existence of the Higgs boson are seen in experiments with the Large Electron Positron collider at CERN, the European Laboratory for Particle Physics.