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photometry
(Encyclopedia)photometry fōtŏmˈətrē, branch of physics dealing with the measurement of the intensity of a source of light, such as an electric lamp, and with the intensity of light such a source may cast on a ...light
(Encyclopedia)light, visible electromagnetic radiation. Of the entire electromagnetic spectrum, the human eye is sensitive to only a tiny part, the part that is called light. The wavelengths of visible light range ...Ibn al-Haytham
(Encyclopedia)Ibn al-Haytham ălhəzĕnˈ [key], 965–c.1040, Arab mathematician. Ibn al-Haytham was born in Basra, but made his career in Cairo, where he supported himself copying scientific manuscripts. Among hi...nebula
(Encyclopedia)nebula nĕbˈyo͝olə [key] [Lat.,=mist], in astronomy, observed manifestation of a collection of highly rarefied gas and dust in interstellar space. Prior to the 1960s this term was also applied to b...Farmer, Moses Gerrish
(Encyclopedia)Farmer, Moses Gerrish, 1820–93, American inventor, b. Boscawen, N.H. He helped build and maintain some of the pioneer telegraph lines of Massachusetts and experimented in multiple telegraphy. He exh...aureole, in physics
(Encyclopedia)aureole ôrˈēōlˌ [key], in physics, luminous circle seen when the sun or other bright light is observed through a diffuse medium, i.e., smoke, thin cloud, fog, haze, or mist. It sometimes occurs a...Geissler tube
(Encyclopedia)Geissler tube gīsˈlər [key], gas discharge tube in which light is produced when an electric discharge passes through the rarefied gas in the tube. The color of the glow depends on the gas used. The...Turrell, James
(Encyclopedia)Turrell, James, 1943–, American installation and land artist, b. Los Angeles, grad. Pomona College (B.A., 1965), Claremont Graduate School (M.F.A., 1973). Turrell's career began in the 1960s art sce...quasar
(Encyclopedia)quasar kwāˈsär [key], one of a class of blue celestial objects having the appearance of stars when viewed through a telescope and currently believed to be the most distant and most luminous objects...Bouts, Dierick
(Encyclopedia)Bouts, Dierick, Dirk, or Thierry dēˈrĭk, dĭrk, tyĕˈrē bouts [key], c.1420–1475, early Netherlandish painter, b. Haarlem, active in Louvain. Bouts was influenced by Roger van der Weyden, the v...Browse by Subject
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