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Al-Biruni, Abu Rayhan Muhammad ibn Ahmad
(Encyclopedia)Al-Biruni or Al Beruni, Abu Rayhan Muhammad ibn Ahmad äbo͞oˈ rīhänˈ məhămˈĭd ĭbˈən äˈməd ăl-bēro͞oˈnē, ăl bĕro͞oˈnē [key], b. 973, d. after 1050, Central Asian scientist. His...Dyson, Sir Frank Watson
(Encyclopedia)Dyson, Sir Frank Watson dīˈsən [key], 1868–1939, English astronomer, b. Ashby-de-la-Zouch, grad. Cambridge. He was astronomer royal of Scotland (1905–10) and of England (from 1910). As director...Bhaskara
(Encyclopedia)Bhaskara əchärˈyə [key] [Skt.,=learned], b. 1114, Indian mathematician and astronomer. According to the custom, he put his learned treatises into verse, adding, however, explanations in prose. His...X-ray astronomy
(Encyclopedia)X-ray astronomy, study of celestial objects by means of the X rays they emit, in the wavelength range from 0.01 to 10 nanometers. X-ray astronomy dates to 1949 with the discovery that the sun emits X ...proper motion
(Encyclopedia)proper motion, in astronomy, apparent movement of a star on the celestial sphere, usually measured as seconds of arc per year; it is due both to the actual relative motions of the sun and the star thr...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...perturbation
(Encyclopedia)perturbation pŭrˌtərbāˈshən [key], in astronomy and physics, small force or other influence that modifies the otherwise simple motion of some object. The term is also used for the effect produce...Adams, John Couch
(Encyclopedia)Adams, John Couch, 1819–92, English astronomer, grad. St. John's College, Cambridge, 1843. By mathematical calculation based on irregularities in the motion of Uranus, he predicted the position of t...Hertzsprung, Ejnar
(Encyclopedia)Hertzsprung, Ejnar īˈnär hĕrtsˈspro͞ong [key], 1873–1967, Danish astronomer. Although trained as a chemical engineer, Hertzsprung made his career in astronomy, specializing in exacting photogr...mass-luminosity relation
(Encyclopedia)mass-luminosity relation, in astronomy, law stating that the luminosity of a star is proportional to some power of the mass of the star. More massive stars are in general more luminous. For stars on t...Browse by Subject
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