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cosmology

(Encyclopedia)cosmology, area of science that aims at a comprehensive theory of the structure and evolution of the entire physical universe. The earliest pre-Ptolemaic theories assumed that the earth was the cent...

astatine

(Encyclopedia)astatine ăsˈtətēn, –tĭn [key] [Gr.,=unstable], semimetallic radioactive chemical element; symbol At; at. no. 85; at. wt. of most stable isotope 210; m.p. 302℃ (estimated); b.p. 337℃ (estima...

refining

(Encyclopedia)refining, any of various processes for separating impurities from crude or semifinished materials. It includes the finer processes of metallurgy, the fractional distillation of petroleum into its comm...

diffusion

(Encyclopedia)diffusion, in chemistry, the spontaneous migration of substances from regions where their concentration is high to regions where their concentration is low. Diffusion is important in many life process...

conduction

(Encyclopedia)conduction, transfer of heat or electricity through a substance, resulting from a difference in temperature between different parts of the substance, in the case of heat, or from a difference in elect...

cholesterol

(Encyclopedia)CE5 cholesterol kəlĕsˈtərōlˌ [key], fatty lipid found in the body tissues and blood plasma of vertebrates; it is only sparingly soluble in water, but much more soluble in some organic solvent...

beryllium

(Encyclopedia)beryllium bərĭlˈēəm [key] [from beryl ], metallic chemical element; symbol Be; at. no. 4; at. wt. 9.01218; m.p. about 1,278℃; b.p. 2,970℃ (estimated); sp. gr. 1.85 at 20℃; valence +2. Ber...

Mimas

(Encyclopedia)Mimas mīˈmăs [key], in astronomy, one of the named moons, or natural satellites, of Saturn. Also known as Saturn I (or S1), Mimas is 244 mi (392 km) in diameter, orbits Saturn at a mean distance of...

Lorentz, Hendrik Antoon

(Encyclopedia)Lorentz, Hendrik Antoon hĕnˈdrək änˈtōn lōˈrĕnts [key], 1853–1928, Dutch physicist, a pioneer in formulating the relations between electricity, magnetism, and light. He was one of the first...

Ligeti, György

(Encyclopedia)Ligeti, György, 1923–2006, Hungarian composer. He studied music in Romania and Hungary, and was a teacher at the Budapest Academy of Music until he fled to Vienna (1956) after the Soviet invasion o...