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International System of Units

(Encyclopedia)International System of Units, officially called the Système International d'Unités, or SI, system of units adopted by the 11th General Conference on Weights and Measures (1960). It is based on the ...

New Madrid Fault System

(Encyclopedia)New Madrid Fault System: see under New Madrid, Mo. ...

Maryland, University System of

(Encyclopedia)Maryland, University System of, state-supported system of higher education in Maryland, est. 1988 as the University of Maryland System, renamed 1997. It includes all but two of the publicly supported ...

California State University System

(Encyclopedia)California State University System, coordinating agency established in 1960 by the merger of individual California state colleges, now consisting of 23 campuses. It constitutes one of the three Califo...

Brahic, André Fernand

(Encyclopedia)Brahic, André Fernand, 1942–2016, French astrophysicist, b. Paris. He was introduced to astrophysics by Evry Schatzman, a leading French theoretician, and obtained his doctorate from the Univ. of P...

retrograde motion

(Encyclopedia)retrograde motion, in astronomy, real or apparent movement of a planet, dwarf planet, moon, asteroid, or comet from east to west relative to the fixed stars. The most common direction of motion in the...

Oort, Jan Hendrik

(Encyclopedia)Oort, Jan Hendrik ōrt [key], 1900–1992, Dutch astronomer. He confirmed (1927) Bertil Lindblad's theory of the Milky Way galaxy's rotation. In the 1950s he and his colleagues used radio astronomical...

light-year

(Encyclopedia)light-year, in astronomy, unit of length equal to the distance light travels in one sidereal year. It is 9.461 × 1012 km (about 6 million million mi). Alpha Centauri and Proxima Centauri, the stars n...

Bode's law

(Encyclopedia)Bode's law [for J. E. Bode], also known as Titius's law or the Titius-Bode law, empirical relationship between the mean distances of the planets from the sun. If each number in the series 0, 3, 6, 12,...

astrophysics

(Encyclopedia)astrophysics, application of the theories and methods of physics to the study of stellar structure, stellar evolution, the origin of the solar system, and related problems of cosmology. The distinctio...