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catastrophism

(Encyclopedia)catastrophism kətăsˈtrəfĭzəm [key], in geology, the doctrine that at intervals in the earth's history all living things have been destroyed by cataclysms (e.g., floods or earthquakes) and replac...

prospecting

(Encyclopedia)prospecting, search for mineral deposits suitable for mining. Modern prospecting has replaced earlier methods based on chance or superstition (e.g., use of the divining rod) with others based on a sci...

Eratosthenes

(Encyclopedia)Eratosthenes ĕrətŏsˈthənēz [key], c.275–c.195 b.c., Greek scholar, b. Cyrene. A pupil of Callimachus in Athens, he became (c.240 b.c.) head of the library at Alexandria. Known for his versatil...

Dutton, Clarence Edward

(Encyclopedia)Dutton, Clarence Edward, 1841–1912, American geologist, b. Wallingford, Conn., grad. Yale, 1860. After service in the army during and after the Civil War, he was a member (1875–91) of the U.S. Geo...

Werner, Abraham Gottlob

(Encyclopedia)Werner, Abraham Gottlob äˈbrähäm gôtˈlōp vĕrˈnər [key], 1750–1817, German geologist. In 1775 he became inspector and teacher in the mining academy at Freiberg, which through his efforts be...

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...

Ptolemaic system

(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...

Shklovsky, Iosif Samuilovich

(Encyclopedia)Shklovsky, Iosif Samuilovich yôsˈĭf səmo͞oēlˈəvĭch shklŏfˈskē [key], 1916–85, Soviet astronomer. He was head of the department of radio-astronomy at the Sternberg Astronomical Institute,...

observatory, orbiting

(Encyclopedia)observatory, orbiting, research satellite designed to study solar radiation, electromagnetic radiation from distant stars, the earth's atmosphere, or the like. Because the atmosphere and other aspects...

dice, in games and gambling

(Encyclopedia)dice [plural of die], small cubes used in games. They are usually made of ivory, bone, wood, plastic, or similar materials. The six sides are numbered by dots from 1 to 6, so placed that the sum of th...