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geodesy

(Encyclopedia)geodesy jēŏdˈĭsē [key] or geodetic surveying, theory and practice of determining the position of points on the earth's surface and the dimensions of areas so large that the curvature of the earth...

gamma radiation

(Encyclopedia)gamma radiation, high-energy photons emitted as one of the three types of radiation resulting from natural radioactivity. It is the most energetic form of electromagnetic radiation, with a very short ...

Eriugena, John Scotus

(Encyclopedia)Eriugena or Erigena, John Scotus skōˈtəs ĕryo͞oˈjĭnə; ĕrĭjˈ– ĕrēˈ– [key] [Lat. Scotus=Irish, Eriugena=born in Ireland], c.810–c.877, scholastic philosopher, born in Ireland. About ...

motorcycle

(Encyclopedia)motorcycle, motor vehicle whose design is based on the bicycle. The German inventor Gottlieb Daimler is generally credited with building the first practical motorcycle in 1885. The motorcycle did not ...

National Radio Astronomy Observatory

(Encyclopedia)National Radio Astronomy Observatory (NRAO), federal observatory for radio astronomy, founded in 1956 and operated under contract with the National Science Foundation by Associated Universities, Inc.,...

niobium

(Encyclopedia)niobium nīōˈbēəm [key], metallic chemical element; symbol Nb; at. no. 41; at. wt. 92.90638; m.p. about 2,468℃; b.p. 4,742℃; sp. gr. 8.57 at 20℃; valence +2, +3, +4, or +5. Niobium is a rare...

Oakland

(Encyclopedia)Oakland, city (1990 pop. 372,242), seat of Alameda co., W Calif., on the eastern side of San Francisco Bay; inc. 1852. Together with San Francisco and San Jose, the city comprises the fourth largest m...

larynx

(Encyclopedia)larynx lârˈĭngks [key], organ of voice in mammals. Commonly known as the voice box, the larynx is a tubular chamber about 2 in. (5 cm) high, consisting of walls of cartilage bound by ligaments and ...

centrifuge

(Encyclopedia)centrifuge sĕnˈtrəfyo͞oj [key], device using centrifugal force to separate two or more substances of different density, e.g., two liquids or a liquid and a solid. The centrifuge consists of a fixe...

ceramics

(Encyclopedia)ceramics sərămˈĭks [key], materials made of nonmetallic minerals that have been permanently hardened by firing at a high temperature, or objects made of such materials. Most ceramics resist heat a...