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Brahmagupta

(Encyclopedia)Brahmagupta bräˌməgo͝opˈtə [key], c.598–c.660, Indian mathematician and astronomer. He was among the first to meaningfully discuss the concepts of zero and of negative numbers. He wrote in ver...

Blaeu, Willem Janszoon

(Encyclopedia)Blaeu, Willem Janszoon vĭˈləm yänˈsōn blou [key], 1571–1638, Dutch cartographer and printer. He studied astronomy and instrument making under the Danish astronomer Tycho Brahe. The printing es...

Rømer, Olaus

(Encyclopedia)Rømer, Olaus or Ole ōläˈo͝os, ōˈlə römˈər [key], 1644–1710, Danish astronomer. He is noted for his discovery that light travels at a definite speed and does not move through space instant...

Dreux

(Encyclopedia)Dreux drö [key], town, Eure-et-Loir dept., N central France. It is an industrial center wher...

Yellowknife

(Encyclopedia)Yellowknife, city (1991 pop. 15,179), capital of the Northwest Territories, Canada, on the north shore of Great Slave Lake, at the mouth of the Yellowknife River. It is the largest city in the Northwe...

Šarec, Marjan

(Encyclopedia)Šarec, Marjan, 1977–, Slovenian political leader and actor, b. Ljubljana, Yugoslavia (now in Slovenia). He had a career as a comedian and political satirist on radio and television before he was el...

hour angle

(Encyclopedia)hour angle, in astronomy, a coordinate in the equatorial coordinate system. The hour angle of a celestial body is the angular distance, expressed in hours, minutes, and seconds (one hour equals 15 deg...

Moscow State University

(Encyclopedia)Moscow State University, at Moscow, Russia, officially M. V. Lomonosov Moscow State Univ.; founded 1755 as Moscow Univ. by the Russian scientist M. V. Lomonosov, renamed Moscow State Univ. after the R...

parsec

(Encyclopedia)parsec pärˈsĕc [key] [parallax + second], in astronomy, basic unit of length for measuring interstellar and intergalactic distances, equal to 206,265 times the distance from the earth to the su...

nutation

(Encyclopedia)nutation, in astronomy, a slight wobbling motion of the earth's axis. The causes of nutation are similar to those of the precession of the equinoxes, involving the varying attraction of the moon on th...