Columbia Encyclopedia

Search results

434 results found

trigonometry

(Encyclopedia)trigonometry [Gr.,=measurement of triangles], a specialized area of geometry concerned with the properties of and relations among the parts of a triangle. Spherical trigonometry is concerned with the ...

black hole

(Encyclopedia)black hole, in astronomy, celestial object of such extremely intense gravity that it attracts everything near it and in some instances prevents everything, including light, from escaping. The term was...

physics

(Encyclopedia)physics, branch of science traditionally defined as the study of matter, energy, and the relation between them; it was called natural philosophy until the late 19th cent. and is still known by this na...

space exploration

(Encyclopedia)CE5 Moon mission assembly CE5 Stages in a moon mission shown counterclockwise from launching on the first day to splashdown on the ninth day. space exploration, the investigation of physical co...

Frederick II, Holy Roman emperor and German king

(Encyclopedia)Frederick II, 1194–1250, Holy Roman emperor (1220–50) and German king (1212–20), king of Sicily (1197–1250), and king of Jerusalem (1229–50), son of Holy Roman Emperor Henry VI and of Consta...

cosmology

(Encyclopedia)cosmology, area of science that aims at a comprehensive theory of the structure and evolution of the entire physical universe. The earliest pre-Ptolemaic theories assumed that the earth was the cent...

motion picture photography

(Encyclopedia)motion picture photography or cinematography, photographic arts and techniques involved in making motion pictures. See also photography, still. Cinematography developed as a separate craft ve...

comet

(Encyclopedia)CE5 Comet: Whatever the direction of a comet's flight, its “tail” always points away from the sun. The tail disappears when the comet is far from the sun. comet [Gr.,=longhaired], a small cele...

radio

(Encyclopedia)CE5 A. AM transmitter B. AM receiver radio, transmission or reception of electromagnetic radiation in the radio frequency range. The term is commonly applied also to the equipment used, especially...

mathematics

(Encyclopedia)mathematics, deductive study of numbers, geometry, and various abstract constructs, or structures; the latter often “abstract” the features common to several models derived from the empirical, or ...