Famous Astronomers and Astrophysicists

Classical Period

Nicolaus Copernicus 1473-1543
developed a simple heliocentric model of the solar system that explained planetary retrograde motion and overturned Greek astronomy
Tycho Brahe 1546-1601
observed a supernova now known as ``Tycho's supernova''; made the most precise observations of stellar and planetary positions then known
Galileo Galilei 1564-1642
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
Johannes Kepler 1571-1630
established the most exact astronomical tables then known; established the three laws of planetary motion
John Babtist Riccioli 1598-1671
made telescopic lunar studies and published detailed lunar maps in which he introduced much nomenclature for lunar objects; discovered the first double star (Mizar)
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''
Christiaan Huygens 1629-1695
discovered Saturn's first satellite, Titan, and the true shape of Saturn's rings
Sir Isaac Newton 1642-1727
developed theories of gravitation and mechanics, and invented differential calculus
Edmond Halley 1656-1742
used his theory of cometary orbits to predict that the comet of 1682 (later named ``Halley's comet'') was periodic
Charles Messier 1730-1817
discovered 19 comets, 13 being original and 6 independent co-discoveries; compiled a famous catalog of deep-sky objects
Joseph-Louis Lagrange 1736-1813
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
William Herschel 1738-1822
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
Giuseppe Piazzi 1746-1826
discovered the largest asteroid, Ceres; accurately measured positions of many stars, resulting in a star catalog
Johann Bode 1747-1826
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
Pierre-Simon Laplace 1749-1827
made important mathematical contributions to differential equations; promoted the solar nebula hypothesis for the origin of the solar system
Heinrich Wilhelm Olbers 1758-1840
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?''
Friedrich Bessel 1784-1846
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
Joseph von Fraunhofer 1787-1826
made detailed wavelength measurements of hundreds of lines in the solar spectrum; designed an achromatic objective lens
Johann Franz Encke 1791-1865
discovered the first short-period comet, now called Encke's comet
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
Wilhelm Beer 1797-1850
prepared and published maps of the Moon and Mars
Thomas Henderson 1798-1844
first to measure distance to a star (Alpha Centauri)
William Lassell 1799-1880
discovered Triton, the largest satellite of Neptune
Sir George Airy 1801-1892
improved orbital theory of Venus and the Moon; studied interference fringes in optics; made a mathematical study of the rainbow
Urbain Le Verrier 1811-1877
accurately predicted the position of Neptune, which led to its discovery
Johann Gottfried Galle 1812-1910
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
Anders Ångström 1814-1874
discovered hydrogen in the solar spectrum; source of the Angstrom unit
Daniel Kirkwood 1814-1895
discovered the ``Kirkwood gaps'' in the orbits of the asteroids between Mars and Jupiter; explained the gaps in Saturn's rings
William Huggins 1824-1910
first to show that some nebulae, including the great nebula in Orion, have pure emission spectra and thus must be gaseous
Sir Joseph Lockyer 1836-1920
discovered in the solar spectrum a previously unknown element that he named helium
Henry Draper 1837-1882
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
Edward Charles Pickering 1846-1919
discovered the first spectroscopic binary star, Mizar
Jacobus Cornelius Kapteyn 1851-1922
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
Edward Barnard 1857-1923
discovered eight comets and Almathea, the fifth moon of Jupiter; also discovered star with largest proper motion, now called Barnard's star

Nobel Laureates

Hannes Alvén 1908-1995
developed the theory of magnetohydrodynamics
Subramanyan Chandrasekhar 1910-1995
Indian-born American
made important theoretical contributions concerning the structure and evolution of stars, especially white dwarfs
William Fowler 1911-1995
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
Antony Hewish 1924-
led the research group that discovered the first pulsar
Arno A. Penzias 1933-
German-born American
co-discovered the cosmic microwave background radiation
Robert W. Wilson 1936-
co-discovered the cosmic microwave background radiation
Joseph H. Taylor, Jr. 1941-
co-discovered the first binary pulsar
Russell Alan Hulse 1950-
co-discovered the first binary pulsar
Annie Jump Cannon 1863-1941
classified spectra of many thousands of stars; published catalogs of variable stars (including 300 she discovered)
Maximilian Wolf 1863-1932
discovered hundreds of asteroids using photography
George E. Hale 1868-1938
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
Henrietta Swan Levitt 1868-1921
discovered the period-luminosity relation for Cepheid variables
Willem de Sitter 1872-1934
studied the astronomical consequences of Einstein's theory of general relativity; deduced that a near-empty universe would expand
Ejnar Hertzsprung 1873-1967
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
Karl Schwarzchild 1873-1916
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
Vesto M. Slipher 1875-1969
first to measure the radial velocity of the Andromeda galaxy
Walter Sydney Adams 1876-1956
identified Sirius B as the first white dwarf star known
Henry Norris Russell 1877-1957
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)
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
Arthur S. Eddington 1882-1944
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
Harlow Shapley 1885-1972
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
Edwin Hubble 1889-1953
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)
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''
Georges-Henri Lemaitre 1894-1966
advanced idea that the Universe originated as a small, dense ``cosmic egg'' that exploded and set its expansion into motion
Rudolph Minkowski 1895-1976
divided supernovae into Types I and II; optically identified many of the early radio sources
Bernard-Ferdinand Lyot 1897-1952
invented the coronagraph
Otto Struve 1897-1963
Russian-born American
made detailed spectroscopic studies of close binary stars; discovered interstellar matter (H II regions)
Fritz Zwicky 1898-1974
Swiss-born 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
Jan Hendrik Oort 1900-1992
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
George Gamow 1904-1968
Russian-born American
first suggested hydrogen fusion as source of solar energy
Karl G. Jansky 1905-1950
discovered radio waves from space, thereby pioneering the birth of radio astronomy
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''
Bruno B. Rossi 1905-1993-
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)
Bart Jan Bok 1906-1983
suggested that small dark globules of interstellar gas and dusk (now called Bok globules) are collapsing to form new stars
Clyde Tombaugh 1906-1997
discovered the planet Pluto
Fred Whipple 1906-
proposed the ``dirty snowball'' model of cometary structure
Grote Reber 1911-
built the first radio telescope (a parabolic reflector 31 feet in diameter), thereby becoming the first radio astronomer
Carl K. Seyfert 1911-1960
discovered the first active galaxy, part of a group now called Seyfert galaxies
John A. Wheeler 1911-
made theoretical contributions to understanding of quantum gravity; coined the term ``black hole''; introduced the concept of ``spacetime foam''
Karl F. von Weizsäcker 1912-
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
James A. Van Allen 1914-
a space scientist best known for discovering the Earth's magnetosphere
Sir Fred Hoyle 1915-
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 and does not agree
Robert H. Dicke 1916-1997
proposed that radiation near 1-cm wavelength is left over from the hot Big Bang; invented the microwave radiometer, used to detect this radiation
George H. Herbig 1920-
independently discovered the Herbig-Haro objects, which are gas clouds associated with young stars
E. Margaret Burbidge 1919-
performed observational research on the spectra of quasars and other peculiar galaxies; contributed to understanding of stellar nucleosynthesis
Edwin E. Salpeter 1924-
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-
identified the first quasar, and discovered many more; determined ages of many globular clusters
Vera Rubin 1928-
measured rotation curves for distant galaxies and ultimately concluded that 90% or more of the universe is made of invisible dark matter
Riccardo Giacconi 1931-
pioneer of x-ray astronomy; participated in discovery of the first known x-ray source outside the solar system (Scorpius X-1)
John N. Bahcall 1934-
made important theoretical contributions to understanding solar neutrinos and quasars
Carl Sagan 1934-1996
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''
James W. Christy 1938-
discovered Pluto's satellite, Charon
William K. Hartmann 1939-
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)
Kip S. Thorne 1940-
contributed to the theoretical understanding of black holes and gravitational radiation; co-founded the Laser Interferometer Gravitational Wave Observatory Project (LIGO)
Stephen W. Hawking 1942-
combined general relativity with quantum theory to predict that black holes should emit radiation and evaporate
Sir Roger Penrose
contributed to the development of general relativity by showing the necessity for cosmological singularities; elucidated the physics of black holes
Jocelyn Bell 1943-
co-discovered the first pulsar
Charles Thomas Bolton 1943-
identified Cygnus X-1 as the first black hole
Paul F. Goldsmith
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-
developed the theory of cosmic evolution known as the inflationary universe
 - By D.Mark Manley