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Mercator, Gerardus

(Encyclopedia)Mercator, Gerardus gārˈhärt krāˈmər [key], 1512–94, Flemish geographer, mathematician, and cartographer. He studied in Louvain, where he had a geographical establishment (1534). From 1537 to 1...

phase, in astronomy

(Encyclopedia)CE5 Phases of the moon phase, in astronomy, the measure of how much of the illuminated surface of a planet or satellite can be seen from a point at a distance from that body; the term is most ofte...

Ballard, Robert Duane

(Encyclopedia)Ballard, Robert Duane bălˈərd [key], 1942–, American marine geologist, b. Wichita, Kans.; Ph.D. Univ. of Rhode Island, 1974. From 1969 to 1997 he was associated with Woods Hole Oceanographic Inst...

neptunium

(Encyclopedia)neptunium nĕpto͞oˈnēəm [key], radioactive chemical element; symbol Np; at. no. 93; mass number of most stable isotope 237; m.p. about 640℃; b.p. 3,902℃ (estimated); sp. gr. 20.25 at 20℃; va...

Cassini

(Encyclopedia)Cassini käs-sēˈnē [key], name of a family of Italian-French astronomers, four generations of whom were directors of the Paris Observatory. Gian Domenico Cassini, 1625–1712, was born in Italy and...

Mount Wilson Observatory

(Encyclopedia)Mount Wilson Observatory, astronomical observatory located in California on Mt. Wilson, near Pasadena. Mt. Wilson Observatory was founded in 1904 by George E. Hale. Its equipment includes 100-in. (2.5...

Sayles, John

(Encyclopedia)Sayles, John (John Thomas Sayles), 1950–, one of America's most influential independent filmmakers as well as a screenwriter, fiction writer, playwright, and actor, b. Schenectady, N.Y., grad. Willi...

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,...

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...

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