Columbia Encyclopedia

(Encyclopedia) year, time required for the earth to complete one orbit about the sun. The solar or tropical year is measured relative to the sun and is equal to 365 days, 5 hr, 48 min, 46 sec of mean solar time (see...

(Encyclopedia) Ptolemaic system tŏlˌəmāˈĭk [key], historically the most influential of the geocentric cosmological theories, i.e., theories that placed the earth motionless at the center of the universe with a...

(Encyclopedia) O'Malley, Frank Ward, 1875–1932, American newspaperman, b. Pittston, Pa. As reporter (1906–19) for the New York Sun he was especially noted for his stories of humor and pathos. Among his books is ...

(Encyclopedia) Montville, town (1990 pop. 16,673), New London co., SE Conn.; founded 1670, inc. 1786. Paper products, sheet metal, computer circuit boards, tachometers, aluminum doors and windows, and boxes are made...

(Encyclopedia) cycle, in astronomy, period of time required for the recurrence of some celestial event. The length of a cycle may be measured relative to the sun or to the fixed stars (see sidereal time). A frequent...

(Encyclopedia) Campbell, John Francis, 1822–85, Scottish Gaelic scholar. He is known for Popular Tales of the West Highlands (4 vol., 1860–62) and Leabhar na Feinne (1872), a collection of Gaelic folk ballads. A...

(Encyclopedia) radial velocity, in astronomy, the speed with which a star moves toward or away from the sun. It is determined from the red or blue shift in the star's spectrum. ...

(Encyclopedia) Hipparchus, fl. 2d cent. b.c., 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...

(Encyclopedia) Webb Space Telescope or James Webb Space Telescope (JWST), is an infrared space telescope, the largest in space at its launc...

(Encyclopedia) umbrella, a small canopy used as a protection against the sun in China, Egypt, and elsewhere in remote antiquity. It was often an emblem of rank. During the Middle Ages the umbrella became almost exti...