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Cornu, Marie Alfred
(Encyclopedia)Cornu, Marie Alfred märēˈ älfrĕdˈ kôrnüˈ [key], 1841–1902, French physicist. From 1867 he was professor at the École polytechnique, Paris. He measured the velocity of light and made import...green flash
(Encyclopedia)green flash or emerald flash, a refractive phenomenon of the atmosphere where the top edge of the setting (or, less frequently, rising) sun will momentarily turn emerald green. The green color lasts f...sky
(Encyclopedia)sky, apparent dome over the earth, background of the clouds, sun, moon, and stars. The blue color of the clear daytime sky results from the selective scattering of light rays by the minute particles o...prism
(Encyclopedia)prism, in optics, a piece of translucent glass or crystal used to form a spectrum of light separated according to colors. Its cross section is usually triangular. The light becomes separated because d...ophthalmoscope
(Encyclopedia)ophthalmoscope ŏfthălˈməskōpˌ [key], instrument used for examining the inner structure of the eye. The device was invented by the German physiologist H. L. F. von Helmholtz in 1851. His model co...Orion Nebula
(Encyclopedia)Orion Nebula, bright diffuse nebula in the constellation Orion; also known as the Great Nebula of Orion and cataloged as M42 or NGC 1976. It is located near the middle of the “sword” hanging from ...seasonal affective disorder
(Encyclopedia)seasonal affective disorder (SAD), recurrent fall or winter depression characterized by excessive sleeping, social withdrawal, depression, overeating, and pronounced weight gain. SAD effects an estima...aberration
(Encyclopedia) CE5 A. Spherical aberration: Light rays near the edge of the lens are bent more and brought to focus nearer to the lens. B. Chromatic aberration: Shorter wavelengths (higher frequencies) are bent m...Grimaldi, Francesco Maria
(Encyclopedia)Grimaldi, Francesco Maria fränchāsˈkō märēˈä grēmälˈdē [key], 1618?–1663, Italian physicist and mathematician. A Jesuit and professor at Bologna, he studied in detail and named the dark ...McGinley, Phyllis
(Encyclopedia)McGinley, Phyllis, 1905–78, American poet, b. Ontario, Oreg. Her light verse treats aspects of modern life with humor and underlying seriousness. Among her best-known collections of verse are A Pock...Browse by Subject
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