| Walter Sydney Adams | 1876-1956 American | identified Sirius B as the first white dwarf star known |
| Sir George Airy | 1801-1892 British | improved orbital theory of Venus and the Moon; studied interference fringes in optics; made a mathematical study of the rainbow |
| Hannes Alvén | 1908-1995 Swedish | developed the theory of magnetohydrodynamics |
| Viktor Ambartsumian | 1908-1996 Soviet | one of the founders of theoretical astrophysics; first to suggest that T Tauri stars are very young and that nearby stellar associations are expanding |
| Anders Ångström | 1814-1874 Swedish | discovered hydrogen in the solar spectrum; source of the Angstrom unit |
| Walter Baade | 1893-1960 German-born American | discovered the asteroids Hidalgo and Icarus; established two different stellar classes: the younger, hotter “Population I” and the older, cooler “Population II” |
| John N. Bahcall | 1934-2005 American | made important theoretical contributions to understanding solar neutrinos and quasars |
| Edward Barnard | 1857-1923 American | discovered eight comets and Almathea, the fifth moon of Jupiter; also discovered star with largest proper motion, now called Barnard's star |
| Wilhelm Beer | 1797-1850 German | prepared and published maps of the Moon and Mars |
| Jocelyn Bell | 1943- British | co-discovered the first pulsar |
| Friedrich Bessel | 1784-1846 Prussian | first to measure distance to the star 61 Cygni; proposed that Sirius has an unseen companion; worked out the mathematical analysis of what are now known as Bessel functions |
| Johann Bode | 1747-1826 German | popularized a relationship giving planetary distances from the Sun, which became known as “Bode's law”; predicted an undiscovered planet between Mars and Jupiter, where the asteroids were later found |
| Bart Jan Bok | 1906-1983 Dutch | suggested that small dark globules of interstellar gas and dusk (now called Bok globules) are collapsing to form new stars |
| Charles Thomas Bolton | 1943- American-born Canadian | identified Cygnus X-1 as the first black hole |
| Tycho Brahe | 1546-1601 Danish | observed a supernova now known as “Tycho's supernova”; made the most precise observations of stellar and planetary positions then known |
| Mike Brown | 1965- American | discovered with his team many trans-Neptunian objects (TNOs) including Eris, the first TNO discovered that is larger than Pluto, which eventually led to the demotion of Pluto to a dwarf planet |
| E. Margaret Burbidge | 1919- British | performed observational research on the spectra of quasars and other peculiar galaxies; contributed to understanding of stellar nucleosynthesis |
| Bernard F. Burke | 1942- American | developed techniques for very-long-baseline interferometry (VLBI) using atomic frequency standards to synchronize radio telescopes at remote locations worldwide, leading to a 1000-fold improvement in angular resolution for radio telescopes; conducted first measurements of intercontinental and transcontinental VLBI |
| Annie Jump Cannon | 1863-1941 American | classified spectra of many thousands of stars; published catalogs of variable stars (including 300 she discovered) |
| Giovanni Cassini | 1625-1712 Italian-born French | measured rotational periods of Jupiter and Mars; discovered four satellites of Saturn and the gap in Saturn's rings now known as “Cassini's division” |
| Subramanyan Chandrasekhar | 1910-1995 Indian-born American | made important theoretical contributions concerning the structure and evolution of stars, especially white dwarfs |
| James W. Christy | 1938- American | discovered Pluto's satellite, Charon |
| Nicolaus Copernicus | 1473-1543 Polish | developed a simple heliocentric model of the solar system that explained planetary retrograde motion and overturned Greek astronomy |
| Robert H. Dicke | 1916-1997 American | proposed that radiation near 1-cm wavelength is left over from the hot Big Bang; invented the microwave radiometer, used to detect this radiation |
| Henry Draper | 1837-1882 American | made first photograph of a stellar spectrum (that of Vega); later photographed spectra of over a hundred stars and published them in a catalog; studied spectrum of Orion Nebula, which he showed was a dust cloud |
| Arthur S. Eddington | 1882-1944 British | first to confirm Einstein's prediction that light will bend near a star; discovered the mass-luminosity relation for stars; theoretically explained the pulsation of Cepheid variables |
| James Ludlow Elliot | 1943-2011 American | discovered the rings of Uranus |
| Johann Franz Encke | 1791-1865 German | discovered the first short-period comet, now called Encke's comet |
| William Fowler | 1911-1995 American | carried out extensive experimental studies of nuclear reactions of astrophysical significance; developed, with others, a complete theory of the formation of chemical elements in the universe |
| Joseph von Fraunhofer | 1787-1826 German | made detailed wavelength measurements of hundreds of lines in the solar spectrum; designed an achromatic objective lens |
| Galileo Galilei | 1564-1642 Italian | performed fundamental observations, experiments, and mathematical analyses in astronomy and physics; discovered mountains and craters on the moon, the phases of Venus, and the four largest satellites of Jupiter: Io, Europa, Callisto, and Ganymede |
| Johann Gottfried Galle | 1812-1910 German | first person to observe Neptune, based on calculations by French mathematician, Urbain Le Verrier; however, Neptune's discovery is usually credited to Le Verrier and English astronomer, John Crouch Adams, who first predicted its position |
| George Gamow | 1904-1968 Russian-born American | first suggested hydrogen fusion as source of solar energy; introduced the term “Big Bang” |
| Riccardo Giacconi | 1931- Italian | pioneer of x-ray astronomy; participated in discovery of the first known x-ray source outside the solar system (Scorpius X-1) |
| Thomas Gold | 1920-2004 American | contributed to our understanding of cosmology, the nature of pulsars as rotating neutron stars, and the origin of planetary hydrocarbons |
| Paul F. Goldsmith | 1948- American | Director of National Astronomy and Ionosphere Center; developed techniques to study structure of dense molecular clouds where star formation is occurring |
| Alan H. Guth | 1947- American | developed the theory of cosmic evolution known as the inflationary universe |
| George E. Hale | 1868-1938 American | revolutionized spectral observations by inventing and using the spectroheliograph; discovered magnetic fields in sunspots; first astronomer to be officially called an astrophysicist; founded the Yerkes, Mt. Wilson, and Palomar Observatories |
| Edmond Halley | 1656-1742 British | used his theory of cometary orbits to predict that the comet of 1682 (later named “Halley's comet”) was periodic |
| William K. Hartmann | 1939- American | well-known painter of astronomical themes; co-developed the most widely accepted theory of the formation of the Moon (from the collision of a giant planetismal with the Earth at the close of the planet-forming period of the solar system) |
| Chushiro Hayashi | 1920-2010 Japanese | discovered the pattern followed by pre-main-sequence stars on H-R diagrams (now called the Hayashi track); discovered the maximum radius for a star of a given mass (the Hayashi limit); made significant contributions to our understanding of Big Bang nucleosynthesis |
| Stephen W. Hawking | 1942-2018 British | combined general relativity with quantum theory to predict that black holes should emit radiation and evaporate |
| Thomas Henderson | 1798-1844 Scottish | first to measure distance to a star (Alpha Centauri) |
| George H. Herbig | 1920-2013 American | independently discovered the Herbig-Haro objects, which are gas clouds associated with young stars |
| Caroline Herschel | 1750-1848 British | discovered several comets and was first woman to discover a comet |
| William Herschel | 1738-1822 British | discovered Uranus and its two brightest moons, Titania and Oberon; discovered Saturn's moons, Mimas and Enceladus; discovered the ice caps of Mars, several asteroids and binary stars; cataloged 2,500 deep sky objects |
| Ejnar Hertzsprung | 1873-1967 Danish | invented the color-magnitude diagram; by studying star clusters, independently discovered the relationship between absolute magnitude and spectral types of stars; a plot of this relationship is now called a Hertzsprung-Russell diagram (or H-R diagram); determined distance to the Small Magellanic Cloud |
| Antony Hewish | 1924- British | led the research group that discovered the first pulsar |
| Kiyotsugu Hirayama | 1874-1943 Japanese | discovered the existence of groups of asteroids with similar orbital elements. He hypothesized that the asteroids in these families (now called Hirayama families) were physically related |
| Sir Fred Hoyle | 1915-2001 British | proponent of the steady-state model of the universe; well-known author of science fiction; proposed that earliest forms of life were carried through space on comets and that these primitive forms of life found their way to Earth; derisively coined the term “Big Bang” for a cosmic theory with which he did not agree |
| Edwin Hubble | 1889-1953 American | first to measure distance to the Andromeda nebula, establishing it to be a separate galaxy; later measured distances to other galaxies and discovered that they recede at a rate proportional to their distance (Hubble's law) |
| William Huggins | 1824-1910 British | first to show that some nebulae, including the great nebula in Orion, have pure emission spectra and thus must be gaseous |
| Russell Alan Hulse | 1950- American | co-discovered the first binary pulsar |
| Christiaan Huygens | 1629-1695 Dutch | discovered Saturn's first satellite, Titan, and the true shape of Saturn's rings |
| Karl G. Jansky | 1905-1950 American | discovered radio waves from space, thereby pioneering the birth of radio astronomy |
| Jacobus Cornelius Kapteyn | 1851-1922 Dutch | discovered that the proper motions of stars were not random, but stars could be divided into two streams moving in opposite directions, representing the rotation of our galaxy |
| Johannes Kepler | 1571-1630 German | established the most exact astronomical tables then known; established the three laws of planetary motion |
| Daniel Kirkwood | 1814-1895 American | discovered the “Kirkwood gaps” in the orbits of the asteroids between Mars and Jupiter; explained the gaps in Saturn's rings |
| Gerard P. Kuiper | 1905-1973 Dutch-born American | discovered Miranda, the fifth satellite of Uranus; discovered Nereid, the second satellite of Neptune; discovered the atmosphere of Titan, Saturn's largest satellite; his spectroscopic studies of Uranus and Neptune led to discovery of comet-like debris at the edge of the solar system, now called “Kuiper's belt” |
| Joseph-Louis Lagrange | 1736-1813 French | developed new methods of analytical mechanics; made many theoretical contributions to astronomy, improving our understanding of lunar motion and the perturbing effects of planets on cometary orbits; found solution to 3-body problem showing there could be two points (now called Lagrange points) in orbit of Jupiter where minor planets could stay almost indefinitely - the Trojan group of asteroids were later discovered at these positions |
| Pierre-Simon Laplace | 1749-1827 French | made important mathematical contributions to differential equations; promoted the solar nebula hypothesis for the origin of the solar system |
| William Lassell | 1799-1880 British | discovered Triton, the largest satellite of Neptune |
| Georges-Henri Lemaitre | 1894-1966 Belgian | advanced idea that the Universe originated as a small, dense “cosmic egg” that exploded and set its expansion into motion |
| Henrietta Swan Levitt | 1868-1921 American | discovered the period-luminosity relation for Cepheid variables |
| Sir Joseph Lockyer | 1836-1920 British | discovered in the solar spectrum a previously unknown element that he named helium |
| Bernard-Ferdinand Lyot | 1897-1952 French | invented the coronagraph |
| Charles Messier | 1730-1817 French | discovered 19 comets, 13 being original and 6 independent co-discoveries; compiled a famous catalog of deep-sky objects |
| Rudolph Minkowski | 1895-1976 German | divided supernovae into Types I and II; optically identified many of the early radio sources |
| Tadashi Nakajima | Japanese | led the group that discovered the first Brown Dwarf |
| Sir Isaac Newton | 1642-1727 English | developed theories of gravitation and mechanics, and invented differential calculus |
| Heinrich Wilhelm Olbers | 1758-1840 German | invented first successful method for calculating cometary orbits; discovered several comets, including the comet of 1815, now called Olber's comet; discovered the asteroids Pallas and Vesta; posed the famous Olber's paradox: “Why is the night sky dark?” |
| Jan Hendrik Oort | 1900-1992 Dutch | calculated distance to center of galaxy; determined period for sun to complete one revolution of Milky Way; calculated the mass of the Milky Way; proposed existence of huge spherical cloud of icy comets (the Oort cloud) left behind from formation of the solar system |
| Cecelia Payne-Gaposchkin | 1900-1979 English | discovered that stars are composed primarily of hydrogren, with helium the second-most abundant element |
| Sir Roger Penrose | 1931- British | contributed to the development of general relativity by showing the necessity for cosmological singularities; elucidated the physics of black holes |
| Arno A. Penzias | 1933- German-born American | co-discovered the cosmic microwave background radiation |
| Giuseppe Piazzi | 1746-1826 Italian | discovered the largest asteroid, Ceres; accurately measured positions of many stars, resulting in a star catalog |
| Edward Charles Pickering | 1846-1919 American | discovered the first spectroscopic binary star, Mizar |
| Grote Reber | 1911-2002 American | built the first radio telescope (a parabolic reflector 31 feet in diameter), thereby becoming the first radio astronomer |
| John Babtist Riccioli | 1598-1671 Italian | made telescopic lunar studies and published detailed lunar maps in which he introduced much nomenclature for lunar objects; discovered the first double star (Mizar) |
| Bruno B. Rossi | 1905-1993 Italian | pioneer of x-ray astronomy and space plasma physics; participated in discovery of the first known x-ray source outside the solar system (Scorpius X-1) |
| Vera Rubin | 1928- American | measured rotation curves for distant galaxies and ultimately concluded that 90% or more of the universe is made of invisible dark matter |
| Henry Norris Russell | 1877-1957 American | used photographic methods to measure stellar parallaxes, leading to the discovery of the relationship between absolute magnitude and spectral types of stars; a plot of this relationship is now called a Hertzsprung-Russell diagram (or H-R diagram) |
| Carl Sagan | 1934-1996 American | was a leader in the search for extraterrestrial intelligence; contributed to most of the space missions to explore Mars and the outer planets; warned that all-out nuclear war could lead to a “nuclear winter” |
| Edwin E. Salpeter | 1924-2008 Austrian-born American | explained how the triple-alpha reaction could make carbon from helium in stars; worked on atomic theory and quantum electrodynamics; co-developed the Bethe-Salpeter equation; contributed to nuclear astrophysics, stellar evolution, statistical mechanics, and plasma physics |
| Allan R. Sandage | 1926-2010 American | identified the first quasar, and discovered many more; determined ages of many globular clusters |
| Bernhard Schmidt | 1879-1935 Swedish-born German | invented and constructed the first Schmidt reflecting telescope using a corrector plate he devised to eliminate aberration of the image |
| Karl Schwarzchild | 1873-1916 German | first to give an exact solution of Einstein's equations of general relativity, giving an understanding of the geometry of space near a point mass; also made the first study of black holes |
| Carl K. Seyfert | 1911-1960 American | discovered the first active galaxy, part of a group now called Seyfert galaxies |
| Irwin I. Shapiro | 1929- American | implemented novel radio or radar techniques for various astrophysical research activities including solar-system tests of general relativity and studies of gravitational lenses and supernovae seeking to determine an accurate value for the Hubble constant |
| Harlow Shapley | 1885-1972 American | discovered the size of our galaxy and the direction of its center by studying the distribution of globular clusters; determined the orbits of many eclipsing binary stars |
| Willem de Sitter | 1872-1934 Dutch | studied the astronomical consequences of Einstein's theory of general relativity; deduced that a near-empty universe would expand |
| Vesto M. Slipher | 1875-1969 American | first to measure the radial velocity of the Andromeda galaxy |
| Friedrich von Struve | 1793-1864 German-born Russian | founded the study of double stars; published catalog of over 3000 binary stars; first to measure distance to the star Vega |
| Otto Struve | 1897-1963 Russian-born American | made detailed spectroscopic studies of close binary stars; discovered interstellar matter (H II regions) |
| Joseph H. Taylor, Jr. | 1941- American | co-discovered the first binary pulsar |
| Kip S. Thorne | 1940- American | contributed to the theoretical understanding of black holes and gravitational radiation; co-founded the Laser Interferometer Gravitational Wave Observatory Project (LIGO) |
| Clyde Tombaugh | 1906-1997 American | discovered the planet Pluto |
| Neil deGrasse Tyson | 1958- American | best known for poplarizing science by hosting the television series NOVA ScienceNow and Cosmos: A SpaceTime Odyssey |
| James A. Van Allen | 1914-2006 American | a space scientist best known for discovering the Earth's magnetosphere |
| Urbain Le Verrier | 1811-1877 French | accurately predicted the position of Neptune, which led to its discovery |
| Karl F. von Weizsäcker | 1912-2005 German | contributed to the development of the model nebular theory for the formation of the solar system; proposed (with Hans Bethe) the proton-proton reaction as the thermonuclear energy source for the sun |
| John A. Wheeler | 1911-2008 American | made theoretical contributions to understanding of quantum gravity; coined the term “black hole”; introduced the concept of “spacetime foam” |
| Fred Whipple | 1906-2004 American | proposed the “dirty snowball” model of cometary structure |
| Robert W. Wilson | 1936- American | co-discovered the cosmic microwave background radiation |
| Maximilian Wolf | 1863-1932 German | discovered hundreds of asteroids using photography |
| Fritz Zwicky | 1898-1974 Swiss-American | observed Coma cluster of galaxies and determined that most of the cluster must be “dark matter”; proposed existence of and then observed dwarf galaxies; proposed existence of supernovas (a term he coined) and that their collapse might lead to neutron stars; anticipated discovery of quasars by proposing that compact blue galaxies might be mistaken for stars; anticipated that dark matter could be studied by observing galaxies that acted as gravitational lenses |
Finnish translation (by Lucja Adamska)
Georgian translation (by Ana Mirilashvili)
German translation (by CarinmyDNA)
Portuguese translation (by Artur Weber)
Russian translation (by Colorings blog)
manley@kent.edu.