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Central Events in Astronomy


Source: Human Accomplishment by Charles Murray, pp 163-166

YearCountryEvent
-500GreecePythagoras of Samos discovers that the morning and the evening star are the same.
-165ChinaChinese astronomers describe sunspots.
-134AlexandriaHipparchus invents a system of magnitude for measuring the brightness of stars, still the basis of the modern system.
-134AlexandriaHipparchus prepares the first accurate, systematic star catalog and sky map.
-130AlexandriaHipparchus calculates the first reasonably accurate estimate of the distance to the moon
140AlexandriaPtolemy's Almagest constructs a model of a geocentric solar system that accurately predicts the movements of the planets.
1514PolandNicolaus Copernicus's Commentariolus is the first statement of the heliocentric theory. It culminates in the publication of De Revolutionibus Orbium Coelestium in 1543.
1572DenmarkTycho Brahe records the first European observation of a supernova, discrediting the Aristotelian system of a fixed sphere of stars.
1604GermanyJohannes Kepler observes a second nova, confirming Brahe's discovery.
1608NetherlandsHans Lippershey and Zacharias Jansen independently invent crude telescopes.
1609GermanyJohannes Kepler's Astronomia Nova contains the first statement of Kepler's first two laws of planetary motion.
1609ItalyGalileo conducts the first telescopic observations of the night sky, transforming the nature of astronomical investigation.
1609ItalyGalileo constructs the first working telescope, 9x magnification initially, improved to 30x by the end of the year.
1610ItalyGalileo discovers four moons of Jupiter and invers that the earth is not the center of all motion. (Simon Marius makes a disputed claim to the same discovery.)
1611Italy
Germany
Galileo, Christoph Scheiner, and Girolamo Fabrici independently demonstrate that sunspots are part of the sun and revolve with it.
1612GermanySimon Marius publishes the first systematic description of hte Andromeda Nebula.
1631FrancePierre Gassendi describes the transit of Mercury.
1655NetherlandsChristiaan Huygens discovers the rings of Saturn. He also discovers the first moon of Saturn, Titan, another in a series of discoveries of planetary satellites, asteroids, and other celestial bodies that continues to the present.
1668EnglandIsaac Newton invents the first working reflecting telescope.
1705EnglandEdmond Halley's A Synopsis of the Astronomy of Comets includes calculation of the orbits of comets and the first prediction of a comet's return.
1718EnglandEdmond Halley discovers stellar motion (proper movement of stars).
1755GermanyImmanuel Kant's Allgemeine Naturgeschichte und Theorie Des Himmels hypothesizes that the solar system is part of a huge, lens-shaped collection of stars, that other such "island universes" exist, and proposes a theory of the evolution of the universe in which particles conglomerated to form heavenly bodies.
1761RussiaMikhail Lomonosov infers the existence of a Venusian atmosphere.
1781EnglandWilliam Herschel discovers Uranus.
1782EnglandJohn Goodricke is the first to observe and eclipsing variable star.
1785EnglandWilliam Herschel's On the Construction of the Heavens is the first quantitative analysis of the Milky Way's shape.
1794GermanyErnst Chladni and Heinrich Olbers defent the extraterrestrial origin of meteorites and offer a scientific explanation of them.
1802GermanyHeinrich Olbers argues that asteroids are fragments of an exploded planet.
1803FranceJean-Baptiste Biot discovers empirical verification of meteorites as extraterrestial objects.
1814GermanyJoseph von Fraunhofer discovers that spectral lines observed in light reflected from the planets are shared, while light from stars contains differing lines, leading to the development of astronomical spectroscopy.
1838Scotland
Germany
Thomas Henderson and Friedrich Bessel are the first to measure a star's heliocentric parallax, permitting an estimate of stellar distance.
1843GermanySamuel Schwabe discovers the sunspot cycle, founding the modern study of solar physics.
1844GermanyFriedrich Bessel infers an unseen "dark companion" star of Sirius, the first known binary star.
1845IrelandWilliam Parsons discovers spiral nebulae.
1846England
France
Germany
John Couch and Urbain le Verrier predict the existence and orbit of Neptune, which is then observed by Johann Galle.
1859GermanyGustav Kirchhoff and Robert Bunsen conduct the first analysis of the chemical composition of the stars, the first step in understanding the evolution of the stars.
1905DenmarkEjnar Hertzsprung defines a scale for color and stellar luminosity, used to establish stellar magnitudes.
1908USAGeorge Hale discovers that sunspots exhibit the Zeeman effect, implying that they are subject to an electromagnetic field.
1912USAHenrietta Leavitt devises a method for determining the luminosity of a cephid variable from its period, thereby enabling a determination of its distance and measurement of other extragalactic distances.
1914USAHenry Russell's "Relations Between the Spectra and Other Characteristics of the Stars" develops a theory of stellar evolution.
1918USAHarlow Shapley determines the center of the galaxy, providing a correct picture of our own galaxy plus the first accurate estimate of its size.
1920USAAlbert Michelson calculates the first measurement of stellar diameter, for the star Betelgeuse.
1924USAEdwin Hubble determines that Andromeda is a galaxy, revolutionizing the understanding of the universe's size and structure.
1927BelgiumGeorges Lemaî�tre introduces the idea of the cosmic egg, the forerunner of the Big Bang theory.
1929USAEdwin Hubble discovers Hubble's Law, introducing the concept of an expanding universe.
1930FranceBernard Lyot invents the coronagraph, permitting extended observations of the sun's coronal atmosphere.
1930GermanyBernhard Schmidt invents the Schmidt camera and telescope, permitting wide-angle views with little distortion.
1930USAClyde Tombaugh discovers Pluto based on analysis of the perturbations in the orbits of the outer planets caused by an unknown body.
1932USAKarl Jansky detects radio waves from space, founding radio astronomy.
1934Switzerland
USA
Fred Zwicky and Walter Baade predict the existence of neutron stars, and discover the difference between novae and supernovae.
1937USAGrote Reber invents the radio telescope.
1938Germany
USA
Hans Bethe and Carl Weizsacker present a detailed case for nuclear fusion as the source of a star's energy.
1942USAGrote Reber prepares the first radio map of the universe, locating individual radio sources.
1944GermanyCarl Weizsacker formulates the planetesimal hypothesis to explain the origin of the solar system.
1948USAGeorge Gamow and Ralph Asher develop the Big Bang theory, employing Hans Bethe's results from thermonuclear reactions.
1949USAFred Whipple discovers the "dirty snowball" composition of comets.