Documents for "Astronomy: Biographies":

• Abbot, Charles Greeley 1872-1973, American astrophysicist, b. Wilton, N.H. He was acting director in 1896 and director in 1907 of the astrophysical observatory of the Smithsonian Institution; he was secretary of the...

• Adams, John Couch 1819-92, English astronomer, grad. St. John's College, Cambridge, 1843. By mathematical calculation based on irregularities in the motion of Uranus, he predicted the position of the then unknown...

• Airy, Sir George Biddell 1801-92, English astronomer. The son of a poor farmer, he distinguished himself as Senior Wrangler at Cambridge, where he was elected fellow of Trinity College (1824) and appointed professor...

• Al-Battani or Albatenius , b. before 858, d. 929, Arab astronomer and mathematician. He is best known in astronomy for his improvements and corrections of the Ptolemaic tradition. His Kitab al-Zij, which in Latin translation was very influential in the Middle Ages and the Renaissance, contains an elaborate set of astronomical tables and discusses a wide range of practical problems in...

• Al-Biruni, Abu Rayhan Muhammad ibn Ahmad b. 973, d. after 1050, Central Asian scientist. His earlier years were disturbed by political troubles, but after 1017 he was patronized by members of the Ghaznavid dynasty of Turkey. He traveled...

• Albumazar 805?-885, Arab astronomer, more fully Abu-Mashar Jafar ibn Muhammad. In his De magnis conjunctionibus he claimed that the world had been created when the seven planets were in conjunction in the first degree of the constellation Aries and that its end would come when they should be in conjunction...

• Al-Farghani or Alfraganus , d. after 861, Arab astronomer. Al-Farghani was born in Farghana, Transoxania (present-day Fergana, Uzbekistan), and died in Egypt. His most important work, written between 833 and 857, is Elements, a thorough, readable, nonmathematical summary of Ptolemaic astronomy. The book, which circulated in several Latin editions, was widely studied in Europe from the 12th to the 17th cent. Two...

• Alfraganus see Al-Farghani.

• Argelander, Friedrich Wilhelm August 1799-1875, German astronomer. He became director of the observatory at the Univ. of Bonn in 1837 and continued there the work of determining the positions of stars that F. W. Bessel had begun at Königsberg....

• Aristarchus of Samos fl. c.310 BC-c.230 BC, Greek astronomer and mathematician of the Alexandrian school. He is said to have been the first to propose a heliocentric or sun-centered theory of the universe. Of his...

• Aryabhata c.476-550, Hindu mathematician and astronomer. He is one of the first known to have used algebra; his writings include rules of arithmetic and of plane and spherical trigonometry, and solutions of...

• Asada Goryu 1734-99, Japanese astronomer who helped to introduce modern astronomical instruments and methods into Japan. Asada spent much of his career in the flourishing commercial city of Osaka, where he...

• Autolycus fl. 4th cent. BC, astronomer and mathematician of Pitane in Aeolis. Of his two extant works, that on the revolving sphere is said to be the oldest completely preserved Greek treatise on a...

• Baade, Walter 1893-1960, German-born American astronomer. From 1919 to 1931 he was on the staff of the Hamburg observatory; from 1931 to 1958, at the Mt. Wilson observatory. Baade studied the Andromeda Galaxy,...

• Bailly, Jean Sylvain 1736-93, French astronomer and politician. His works on astronomy and on the history of science (notably the Essai sur la théorie des satellites de Jupiter ) were distinguished both for scientific interest and literary elegance and earned him membership in the French Academy, the Academy of Sciences, and the Academy of Inscriptions. He was elected...

• Barnard, Edward Emerson 1857-1923, American astronomer, b. Nashville, Tenn., grad. Vanderbilt Univ., 1887. From 1887 to 1895 he was astronomer at Lick Observatory in California, and from 1895 he was professor of practical...

• Belopolsky, Aristarkh Apollonovich 1854-1934, Russian astrophysicist, grad. Moscow Univ. (1877). He worked at the Moscow Observatory and from 1888 at the Pulkovo Observatory, where he became vice director in 1908. He was among the...

• Bessel, Friedrich Wilhelm 1784-1846, German astronomer and mathematician. He became (1810) director of the new observatory at Königsberg and professor of astronomy at the Univ. of Königsberg. Among his many achievements...

• Bode, Johann Elert 1747-1826, German astronomer. From 1772 to 1825 he was astronomer of the Academy of Science, Berlin, and from 1786, director of the Berlin Observatory. He is celebrated as the founder (1774) of the Berliner Astronomisches Jahrbuch, but his most noted contribution to astronomy is the Uranographia (1801), a collection of star maps and a catalog of 17,240 stars and nebulae, 12,000 more than had appeared in earlier charts. In 1772 he devised a formula to express the relative distances of the...

• Bond, George Phillips 1825-65, American astronomer, b. near Boston, grad. Harvard, 1845. He became the assistant of his father, William Cranch Bond, and in 1859 succeeded him as director of the Harvard College...

• Bond, William Cranch 1789-1859, American astronomer, b. Portland, Maine. He early aided his father in the trades of silversmith and clockmaker in Boston. He soon became an expert in the making of chronometers and by...

• Bradley, James 1693-1762, English astronomer. His discovery of the aberration of light, announced in 1728, provided an important line of evidence for the motion of the earth around the sun. In 1742 Bradley became...

• Brahe, Tycho 1546-1601, Danish astronomer. The most prominent astronomer of the late 16th cent., he paved the way for future discoveries by improving instruments and by his precision in fixing the positions of...

• Brahmagupta c.598-c.660, Indian mathematician and astronomer. He wrote in verse the Brahma-sphuta-siddhanta [improved system of Brahma], a standard work on astronomy containing two chapters on mathematics that...

• Burbidge, Margaret (Eleanor Margaret Burbidge), 1925-, Anglo-American astronomer. She was the first woman appointed director (1972-73) of the Royal Greenwich Observatory and was named (1982) president of the American...

• Burnham, Sherburne Wesley 1838-1921, American astronomer, b. Thetford, Vt. After serving as observer at Dearborn Observatory, Chicago (1877-81, 1882-84), and as astronomer at Lick Observatory (1888-92), he was from 1893...

• Cannon, Annie Jump 1863-1941, American astronomer, b. Dover, Del. In 1897 she became an assistant in the Harvard College Observatory, where (1911-38) she was astronomer and curator of astronomical photographs...

• Cassini name of a family of Italian-French astronomers, four generations of whom were directors of the Paris Observatory. Gian Domenico Cassini, 1625-1712, was born in Italy and distinguished himself while at Bologna by his studies of the sun and planets, particularly Jupiter; he determined rotational periods for Jupiter, Mars, and Venus...

• Celsius, Anders 1701-44, Swedish astronomer. While professor of astronomy at the Univ. of Uppsala (1730-44), he traveled through Germany, France, and Italy, visiting great observatories. At Nuremberg in 1733 he...

• Clark, Alvan 1804-87, American astronomer and maker of astronomical lenses, b. Ashfield, Mass. In 1846 the firm of Alvan Clark & Sons was established at Cambridgeport, Mass.; it became famous as the...

• Cleomedes fl. 2d cent., Greek astronomer. In a treatise on the circular theory of heavenly bodies, he recorded several hypotheses, e.g., the earth's spherical form and the moon's revolutions, which were...

• Copernicus, Nicholas Pol. Mikotaj Kopérnik, 1473-1543, Polish astronomer. After studying astronomy at the Univ. of Kraków, he spent a number of years in Italy studying various subjects, including medicine and canon law. He lectured c.1500 in...

• Darwin, Sir George Howard 1845-1912, English astronomer and mathematician; 2d son of Charles Darwin. He was Plumian professor (from 1883) of astronomy and experimental philosophy at Cambridge, and a recognized authority on...

• De la Rue, Warren 1815-89, British scientist and inventor. Especially noted as an astronomer, he was a pioneer in celestial photography. He adapted the wet-plate process to lunar photography and invented (1858) for...

• De Sitter, Willem see Sitter, Willem de.

• Delambre, Jean Baptiste Joseph 1749-1822, French astronomer and mathematician. He was a member of the bureau of longitudes from 1795 and professor at the Collège de France from 1807. With P. F. A. Méchain he measured (1791-99)...

• Donati, Giovanni Battista 1826-73, Italian astronomer, b. Pisa. Serving as director of the Florence Observatory from 1864, he was a pioneer in the spectroscopic study of the stars and the sun. Donati was the first to...

• Dreyer, Johan Ludwig Emil 1852-1926, Danish astronomer, b. Copenhagen, who worked in Great Britain. He was assistant astronomer at the earl of Rosse's observatory, Parsonstown (now Birr), Ireland (1874-78), and at the...

• Dyson, Sir Frank Watson 1868-1939, English astronomer, b. Ashby-de-la-Zouch, grad. Cambridge. He was astronomer royal of Scotland (1905-10) and of England (from 1910). As director (1910-33) of Greenwich Observatory he...

• Eddington, Sir Arthur Stanley 1882-1944, British astronomer and physicist. He was chief assistant (1906-13) at the Royal Observatory, Greenwich, and was from 1913 Plumian professor of astronomy at Cambridge, where he was...

• Encke, Johann Franz 1791-1865, German astronomer. He was assistant (1816-22) and director (1822-25) of the observatory at Seeberg (near Gotha) and director (from 1825) of the Berlin Observatory. He is known for his...

• Eudoxus of Cnidus 408?-355? BC, Greek astronomer, mathematician, and physician. From the accounts of various ancient writers, he appears to have studied with Plato in Athens, spent some time in Heliopolis, Egypt,...

• Flammarion, Camille 1842-1925, French astronomer and author. He served for some years at the Paris Observatory and the Bureau of Longitudes, and in 1883 he set up a private observatory at Juvisy (near Paris) and...

• Flamsteed, John 1646-1719, English astronomer. He was appointed (1675) astronomer royal by King Charles II and carried on his researches at Greenwich Observatory. Over his protests—he did not consider it ready...

• Fleming, Sir Sandford see standard time.

• Freundlich, Erwin Finlay 1885-1964, German astronomer. Freundlich obtained a doctorate in mathematics at Göttingen, then joined the Royal Observatory at Berlin, where he worked under the direction of Albert Einstein. His...

• Galileo (Galileo Galilei) , 1564-1642, great Italian astronomer, mathematician, and physicist. By his persistent investigation of natural laws he laid foundations for modern experimental science, and by the construction of...

• Galle, Johann Gottfried 1812-1910, German astronomer. He is noted for his discovery of the planet Neptune, Sept. 23, 1846, by following the guidance of calculations by Leverrier. Galle was then a member of the staff of the Berlin Observatory and had discovered three comets. In 1851 he became professor of astronomy at Breslau and director of the observatory there. His...

• Ganesa b. 1507, d. after 1564, Indian astronomer. As a boy of 13 in a village N of Mumbai, Ganesa wrote a treatise on astronomy, the Grahalaghava, which has often been reprinted and which has inspired many commentaries. In 1525 he composed a book of lunar tables that was also widely studied. His other works on astronomy, astrology, and Hindu...

• Gill, Sir David 1843-1914, Scottish astronomer, educated at the Univ. of Aberdeen. He made observations of the transits of Venus and Mars and investigated the solar parallax. As astronomer royal (1879-1907) at...

• Hagen, Johannes Georg 1847-1930, American astronomer and mathematician, b. Austria. A Jesuit, he came in 1880 to the United States to teach. In 1888 he was made director of the astronomical observatory at Georgetown...

• Hale, George Ellery 1868-1938, American astronomer, b. Chicago, grad. Massachusetts Institute of Technology, 1890. He founded and directed three great observatories (Yerkes, Mt. Wilson, and Palomar), each in its time...

• Halley, Edmond 1656-1742, English astronomer and mathematician. He is particularly noted as the first astronomer to predict the return of a comet and the first to point out the use of a transit of Venus in...

• Herschel family of distinguished English astronomers.

• Hertzsprung, Ejnar 1873-1967, Danish astronomer. Although trained as a chemical engineer, Hertzsprung made his career in astronomy, specializing in exacting photographic observations of stars. In 1905 he discovered...

• Hevelius, Johannes 1611-87, Polish astronomer, b. Danzig. From a finely equipped observatory in his house at Danzig, assisted by his wife Elizabeth, he made valuable observations of the moon's surface, discovered...

• Hipparchus fl. 2d cent. BC, Greek astronomer, b. Nicaea, Bithynia. He is the first systematic astronomer of whom there are records. He made his observations chiefly on the island of Rhodes. Ptolemy's...

• Horrocks, Jeremiah 1618?-1641, English astronomer. He made the first observation of the transit of Venus. His Venus in sole visa, which narrates this experience, was printed by Hevelius in 1662. The transit occurred on Nov. 24, 1639; Horrocks watched the small shadow of the planet move part way across the disk of light on a...

• Hough, George Washington 1836-1909, American astronomer, b. Montgomery co., N.Y., grad. Union College, 1856. He discovered 627 double stars and made systematic studies of the surface of Jupiter. Many instruments for use...

• Hoyle, Sir Fred hoil , 1915-2001, British astrophysicist and mathematician, b. Bingley, Yorkshire. During the years of World War II, Hoyle primarily worked on technical problems related to radar. As a diversion, he...

• Hubble, Edwin Powell 1889-1953, American astronomer, b. Marshfield, Mo. He did research (1914-17) at Yerkes Observatory, and joined (1919) the staff of Mt. Wilson Observatory, Pasadena, Calif., of which he became...

• Huggins, Sir William 1824-1910, English astronomer. Using a spectroscope, he began to study the chemical constitution of stars from the observatory attached to his home in Tulse Hill, London. He proved that while some...

• Hypsicles of Alexandria astronomer of ancient Greece. Some authorities place Hypsicles in the 2d cent. BC and some in the 2d cent. AD The 14th and 15th books of Euclid's Elements, which discuss regular many-sided solids,...

• Jansky, Karl Guthe 1905-50, American radio engineer; b. Norman, Okla. After graduating (1927) from the Univ. of Wisconson, he joined the Bell Telephone Laboratories. While trying to determine the causes of radio...

• Janssen, Pierre Jules César 1824-1907, French astronomer. In 1857-58, in Peru, he worked on the determination of the magnetic equator; in the Azores (1867) he examined magnetic and topographical conditions; and in Japan...

• Jeans, Sir James Hopwood 1887-1946, English mathematician, physicist, and astronomer. He was professor of applied mathematics at Princeton Univ. (1905-9), later lectured at Cambridge (1910-12) and Oxford (1922), and was...

• Kapteyn, Jacobus Cornelius 1851-1922, Dutch astronomer. He was an authority on the Milky Way, of which he made notable statistical studies; he constructed a model of the galaxy known as the "Kapteyn universe." He computed the positions of the stars of the Southern Hemisphere photographed by Sir David Gill and in 1904 announced the discovery of two streams of stars moving in opposite directions in the...

• Keeler, James Edward 1857-1900, American astronomer, b. La Salle, Ill. At the age of 21 he went on the Naval Observatory expedition to Colorado to observe the solar eclipse of July, 1878. In 1886 he became an assistant...

• Kepler, Johannes 1571-1630, German astronomer. From his student days at the Univ. of Tübingen, he was influenced by the Copernican teachings. From 1593 to 1598 he was professor of mathematics at Graz and while...

• Kuiper, Gerard Peter 1905-73, American astronomer, b. the Netherlands. Kuiper is considered to be the father of modern planetary science for his wide ranging studies of the solar system. Among his discoveries were the atmosphere of Saturn 's satellite Titan (1944), the carbon dioxide atmosphere on Mars (1948), Uranus 's satellite Miranda (1948), and Neptune 's satellite Nereid (1949). He proposed (1951) the existence of a disk-shaped region of minor planets outside the orbit of Neptune (now called the Kuiper belt) as a source for short-period comets —those making complete orbits around the sun in less than 200 years (see also Oort, Jan Hendrik ). During the 1960s Kuiper served as chief scientist for the Ranger lunar-probe program, choosing crash-landing sites on the moon; by analyzing Ranger photographs, he helped to identify sites for...

• Lacaille, Nicolas Louis de 1713-62, French astronomer. As a result of his success in making meridional measurements in France under the patronage of the duke of Bourbon he was elected to the French Academy. He also became...

• Lalande, Joseph Jérôme Lefrançais de 1732-1807, French astronomer. Under the direction of the French Academy of Science, he went to Berlin in 1751 to make observations on the parallax of the moon for comparison with those that...

• Langley, Samuel Pierpont 1834-1906, American scientist, b. Roxbury, Mass., received only a high school education but continued his studies in science in Boston libraries. He became, in 1866, professor of physics at the...

• Laplace, Pierre Simon, marquis de 1749-1827, French astronomer and mathematician. At 18 he went to Paris, proved his gift for mathematical analysis to Jean le Rond d'Alembert, and was made professor of mathematics in the École...

• Lemaître, Georges, Abbé 1894-1966, Belgian astrophysicist, mathematician, and Catholic priest. In 1927 he became professor of astrophysics at the Univ. of Louvain and proposed the big-bang theory to help link Einstein's...

• Lemonnier, Pierre Charles 1715-99, French astronomer. For many years he was professor of physics at the Collège de France. He studied the moon and the influence of Saturn on the motion of Jupiter, determined the positions...

• Leverrier, Urbain Jean Joseph 1811-77, French astronomer who made calculations that led to the discovery of the planet Neptune. In considering the perturbations of Uranus , Leverrier made calculations indicating the presence of an unknown planet in an orbit outside that of Uranus. At the time, this was considered the crowning achievement of mathematical astronomy...

• Lockyer, Sir Joseph Norman 1836-1920, English astronomer, educated on the Continent. One of the first to make a spectroscopic examination of the sun and stars, he devised (1868), independently of P. J. C. Janssen, a method...

• Lovell, Sir Bernard (Sir Alfred Charles Bernard Lovell), 1913-, English radio astronomer, b. Oldland Common, Gloucestershire, England, Ph.D. Univ. of Bristol, 1936. He was a member of the cosmic-ray research team at...

• Lowell, Percival 1855-1916, American astronomer, b. Boston, grad. Harvard, 1876; brother of Abbott Lawrence Lowell and Amy Lowell. He visited Korea and Japan, where he acted as counselor and foreign secretary to...

• Müller, Johannes see Regiomontanus.

• Maskelyne, Nevil 1732-1811, English astronomer. Maskelyne received his education at Westminster School and Trinity College, Cambridge. Appointed astronomer royal at the Royal Observatory in 1765, he held this post...

• Mayer, Johann Tobias 1723-62, German mathematician and astronomer. In 1751 he became professor of economics and mathematics at the Univ. of Göttingen, and in 1754 director of the observatory there. He is especially...

• Menzel, Donald Howard 1901-76, American astrophysicist, b. Florence, Colo. From 1926 to 1932 he was with the Lick Observatory in Calif. In 1932 he joined the faculty at Harvard, where he became professor (1938) of astrophysics and director (1954) of the observatory. An authority on the sun's chromosphere, he discovered...

• Mitchell, Maria 1818-89, American astronomer and educator, b. Nantucket, Mass. Mitchell taught school in Nantucket, and later became a librarian. On Oct. 1, 1847, Mitchell discovered a comet (1847 VI) not far from...

• Newcomb, Simon 1835-1909, American astronomer, b. Nova Scotia, grad. Lawrence Scientific School, Harvard, 1858. Living in the United States from 1853, he was appointed (1857) a computer on the American Nautical Almanac and later (1877-97) was its director. He was professor of mathematics in the U.S. navy from 1861 until his retirement in 1897, professor of mathematics and astronomy at Johns Hopkins from 1884 to...

• Olbers, Heinrich Wilhelm Matthäus 1758-1840, German astronomer and physician. He originated (1797) the first satisfactory method for calculating the orbits of comets, but despite the fame it brought him, he remained an amateur...

• Oort, Jan Hendrik 1900-1992, Dutch astronomer. He confirmed (1927) Bertil Lindblad's theory of the Milky Way galaxy's rotation. In the 1950s he and his colleagues used radio astronomical means to map the spiral-arm...

• Parsons, William see Rosse, William Parsons, 3d earl of.

• Perrine, Charles Dillon 1867-1951, American astronomer, b. Steubenville, Ohio. He was on the staff of Lick Observatory (1893-1909) and was (1909-36) director of the Argentine National Observatory in South America. He was...

• Piazzi, Giuseppe 1746-1826, Italian astronomer, a Theatine priest from 1769. He became (1781) professor of mathematics at the Univ. of Palermo, supervised construction of a government observatory (opened 1791) at...

• Picard, Jean 1620-82, French astronomer, noted for having made the first accurate measurement of a degree of the earth's meridian. The figures he established were of great value to Newton in his calculation of...

• Pickering, Edward Charles 1846-1919, American astronomer and physicist, b. Boston, grad. Harvard (B.S., 1865); brother of W. H. Pickering. He was professor of physics (1868-77) at the Massachusetts Institute of Technology...

• Pickering, William Henry 1858-1938, American astronomer, b. Boston, grad. Massachusetts Institute of Technology (B.S., 1879). He taught at the Massachusetts Institute of Technology (1880-87) and at Harvard Observatory...

• Ptolemy (Claudius Ptolemaeus), fl. 2d cent. AD, celebrated Greco-Egyptian mathematician, astronomer, and geographer. He made his observations in Alexandria and was the last great astronomer of ancient...

• Rømer, Olaus 1644-1710, Danish astronomer. He is noted for his discovery that light travels at a definite speed and does not move through space instantaneously. While assistant (1672-79) at the Royal...

• Reber, Gröte 1911-2002, American radio engineer, b. Chicago, Ill. After graduating from the Armour Institute of Technology (now the Illinois Institute of Technology) in 1933, Reber worked for several radio...

• Rheticus (Georg Joachim von Lauchen) , 1514-76, German astronomer, mathematician, and first disciple of Copernicus. In 1540 he printed a summary of heliocentric ideas in the Narratio prima and in 1542 supervised...

• Ritchey, George Willis 1864-1945, American astronomer, b. Meigs co., Ohio, studied at the Univ. of Cincinnati (1883-84, 1886-87). He was superintendent of instrument construction (1899-1904) at Yerkes Observatory and...

• Rittenhouse, David 1732-96, American astronomer and instrument maker, b. near Germantown, Pa., self-educated. A clockmaker by trade, he developed great skill in the making of mathematical instruments. He was called...

• Roemer, Olaus see Rømer, Olaus.

• Rosse, William Parsons, 3d earl of 1800-1867, British astronomer and constructor of telescopes. He served as member of Parliament for King's Co., Ireland (1821-34), Irish representative peer (from 1845), president of the British...

• Russell, Henry Norris 1877-1957, American astronomer, b. Oyster Bay, N.Y., grad. Princeton, 1897. In 1902 he went to Cambridge, England, to study. He returned to Princeton in 1905, was professor of astronomy there...

• Sagan, Carl Edward 1934-96, American astronomer and popularizer of science, b. New York City. Early in his career he investigated radio emissions from Venus and concluded that the cause was a surface temperature of...

• Scheiner, Christoph 1579?-1650, German astronomer and mathematician, a Jesuit priest. He taught at Ingolstadt, Rome, and elsewhere and became rector of a Jesuit college at Neisse, Germany, in 1622. His observation of...

• Schiaparelli, Giovanni Virginio 1835-1910, Italian astronomer. He was director (1862-1900) of the Brera Observatory, Milan. He is especially noted for having detected (1877) on the surface of the planet Mars the markings that he...

• Schwabe, Samuel Heinrich 1789-1875, German apothecary and amateur astronomer. In the hope of discovering a new planet between Mercury and the sun, he made daily observations and tallies of sunspots. In 1843, after 17...

• Secchi, Pietro Angelo 1818-78, Italian astronomer, a Jesuit priest. He was director of the observatory of the Gregorian Univ., Rome, from 1849. He is known especially for his work in spectroscopy and was a pioneer in...

• Shapley, Harlow 1885-1972, American astronomer, b. Nashville, Mo., grad. Univ. of Missouri, 1910, Ph.D. Princeton, 1913. He was astronomer at Mt. Wilson Observatory from 1914 to 1921, when he became director of...

• Shklovsky, Iosif Samuilovich 1916-85, Soviet astronomer. He was head of the department of radio-astronomy at the Sternberg Astronomical Institute, Moscow, and professor of astronomy at Moscow State Univ. He showed, in 1946,...

• Sitter, Willem de 1872-1934, Dutch astronomer and mathematician. He was professor from 1908 at the Univ. of Leiden and in 1919 became director of its observatory. His early work on the motions of Jupiter and its...

• Slipher, Vesto Melvin 1875-1969, American astronomer, b. Mulberry, Ind. From 1901 he was at Lowell Observatory, Flagstaff, Ariz., where he served as director (1917-54). Much of his attention was devoted to the...

• Struve family of astronomers. Friedrich Georg Wilhelm von Struve, 1793-1864, was born in Germany but later lived in Russia. While director (1817-39) of Dorpat Observatory he wrote Stellarum Duplicum et Multiplicum (1837), which proved that double stars are not exceptional and that star systems are governed by the laws of gravity. He made substantial contributions to the study of galactic structure and also...

• Tombaugh, Clyde W. 1906-97, American astronomer, b. Streator, Ill. Although lacking formal training or a college degree, he was hired in 1929 as an assistant by the Lowell Observatory to continue the search for a planet beyond Neptune, which had been initiated by Percival Lowell. Tombaugh used a blink microscope to compare photographs of a small part of the night sky and detect the planet. After ten months of painstaking comparisons, on Feb. 18, 1930, he found Pluto in the constellation Gemini. After...

• Tycho Brahe see Brahe, Tycho.

• Ulugh-Beg or Ulug-Beg , 1394-1449, Timurid ruler and astronomer. The grandson of Timur (or Tamerlane), he succeeded to the Timurid domain in 1447. A patron of the arts and sciences, he established an astronomical...

• Whipple, Fred Lawrence 1906-2004, American astronomer, b. Red Oak, Iowa. After graduating from the Univ. of California, Berkeley (Ph.D. 1931), he accepted a position at Harvard, where he remained for the rest of his...

• Wilson, Robert Woodrow 1936-, American radio astronomer, b. Houston, Tex., Ph.D. California Institute of Technology, 1962. In 1964 he and co-researcher Arno Penzias began monitoring radio waves in the Milky Way galaxy with...

• Young, Charles Augustus 1834-1908, American astronomer, b. Hanover, N.H., grad. Dartmouth, 1853. He discovered the reversing layer of the solar atmosphere and proved the gaseous nature of the sun's corona. He was a...

• Zwicky, Fritz 1898-1974, Swiss-American astrophysicist, b. Bulgaria, educated at Zürich. Associated with the California Institute of Technology after his arrival in the United States in 1925, he became...