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Pan, in astronomy

(Encyclopedia)Pan, in astronomy, one of the named moons, or natural satellites, of Saturn. Also known as Saturn XVIII (or S18), Pan is 12.5 mi (20 km) in diameter, orbits Saturn at a mean distance of 83,000 mi (133...

perturbation

(Encyclopedia)perturbation pŭrˌtərbāˈshən [key], in astronomy and physics, small force or other influence that modifies the otherwise simple motion of some object. The term is also used for the effect produce...

Lyra

(Encyclopedia)Lyra līˈrə [key] [Lat.,=the lyre], northern constellation lying S of Draco, E of Hercules, and W of Cygnus. Although many civilizations represented it as a bird, it was also depicted as a tortoise....

Cooper Union for the Advancement of Science and Art

(Encyclopedia)Cooper Union for the Advancement of Science and Art, accredited institution of higher education; in New York City; coeducational; chartered and opened in 1859. Founded by Peter Cooper, it pioneered in...

Hooke, Robert

(Encyclopedia)Hooke, Robert ho͝ok [key], 1635–1703, English physicist, mathematician, and inventor. He became curator of experiments for the Royal Society (1662), professor of geometry at Gresham College (1665),...

Slipher, Vesto Melvin

(Encyclopedia)Slipher, Vesto Melvin slīˈfər [key], 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 h...

nebula

(Encyclopedia)nebula nĕbˈyo͝olə [key] [Lat.,=mist], in astronomy, observed manifestation of a collection of highly rarefied gas and dust in interstellar space. Prior to the 1960s this term was also applied to b...

Kuhn, Thomas Samuel

(Encyclopedia)Kuhn, Thomas Samuel, 1922–96, American philosopher and historian of science, b. Cincinnati, Ohio. He trained as a physicist at Harvard (Ph.D. 1949), where he taught the history of science from 1948 ...

Thomson, Sir John Arthur

(Encyclopedia)Thomson, Sir John Arthur, 1861–1933, Scottish naturalist and writer. From 1899 to 1930 he was Regius professor of natural history at the Univ. of Aberdeen. In 1924 he lectured at Union Theological S...

precession of the equinoxes

(Encyclopedia)CE5 Precession of the equinoxes (the points at which the earth's celestial equator intersects its ecliptic) is due to the slow rotation of the earth's axis around a perpendicular to the ecliptic. ...