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lepton

(Encyclopedia)lepton lĕpˈtŏnˌ [key] [Gr.,=light (i.e., lightweight)], class of elementary particles that includes the electron and its antiparticle, the muon and its antiparticle, the tau and its antiparticle, ...

promethium

(Encyclopedia)promethium prōmēˈthēəm [key], artificially produced radioactive chemical element; symbol Pm; at. no. 61; mass no. of most stable isotope 145; m.p. 1,042℃; b.p. 3,000℃ (estimated); sp. gr. unk...

hydrogen bomb

(Encyclopedia)hydrogen bomb or H-bomb, weapon deriving a large portion of its energy from the nuclear fusion of hydrogen isotopes. In an atomic bomb, uranium or plutonium is split into lighter elements that togethe...

stellar populations

(Encyclopedia)stellar populations, two broadly contrasting distributions of star types that are characteristic of different parts of a galaxy. Population I stars are young, recently formed stars, whereas population...

Crawford, Joan

(Encyclopedia)Crawford, Joan, 1908–77, American movie star, b. San Antonio, Tex., as Lucille Le Sueur. After working as a Broadway chorus dancer, Crawford began making films in 1926, eventually moving from musica...

Conte, Giuseppe

(Encyclopedia)Conte, Giuseppe, 1964–, Italian political leader, grad. Sapienza Univ. of Rome law school, 1988. A law professor at the Univ. ...

absinthe

(Encyclopedia)absinthe ăbˈsĭnth [key], an emerald-green liqueur distilled from wormwood and other aromatics, including angelica root, sweet-flag root, star anise, and dittany, which have been macerated and steep...

Heinlein, Robert Anson MacDonald

(Encyclopedia)Heinlein, Robert Anson MacDonald hīˈlīn [key], 1907–88, American science-fiction writer, b. Butler, Mo. His best-known novel, Stranger in a Strange Land (1961), concerns a young man who is raised...

Frederick, city, United States

(Encyclopedia)Frederick, city (2020 pop. 78,171), seat of Frederick co., NW Md.; settled 1745, inc. 1817. The processing center of a fertile farm and dairying area, i...

Gill, Sir David

(Encyclopedia)Gill, Sir David gĭl [key], 1843–1914, Scottish astronomer, educated at the Univ. of Aberdeen. He made observations of the transits of Venus and Mars and investigated the solar parallax. As astronom...