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tachyon

(Encyclopedia)tachyon tăkˈēŏnˌ [key], hypothetical elementary particle that travels only at speeds exceeding that of light. According to the theory of relativity, the speed of light is the limiting velocity fo...

Wilson, Benjamin

(Encyclopedia)Wilson, Benjamin, 1721–88, English portrait painter and electrician who opposed Benjamin Franklin's theory of positive and negative electricity. Instead, Wilson supported Newton's gravitational-opti...

Boolean algebra

(Encyclopedia)Boolean algebra bo͞oˈlēən [key], an abstract mathematical system primarily used in computer science and in expressing the relationships between sets (groups of objects or concepts). The notational...

supersymmetry

(Encyclopedia)supersymmetry, in physics, theory concerning the relationship of the elementary particles called boson to those known as fermions, and vice versa, and linking the four fundamental forces. In supersymm...

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 ...

flame

(Encyclopedia)flame, phenomenon associated with the chemical reaction of a gas that has been heated above its kindling temperature with some other gas, usually atmospheric oxygen (see combustion). The heat and ligh...

Hamilton, Sir William Rowan

(Encyclopedia)Hamilton, Sir William Rowan, 1805–65, Irish mathematician and astronomer, b. Dublin. A child prodigy, he had mastered 13 languages by the age of 13 and was still an undergraduate when he became prof...

lignite

(Encyclopedia)lignite lĭgˈnīt [key] or brown coal, carbonaceous fuel intermediate between coal and peat, brown or yellowish in color and woody in texture. It contains more moisture than coal and tends to dry and...

Aristoxenus of Tarentum

(Encyclopedia)Aristoxenus of Tarentum ărĭstŏkˈsənəs, tərĕnˈtəm [key], fl. 4th cent. b.c., pupil of Aristotle. He marks a turning point in Greek musical theory by being the first to base theory on analysis...

Giddings, Franklin Henry

(Encyclopedia)Giddings, Franklin Henry, 1855–1931, American sociologist, b. Fairfield co., Conn., grad. Union College, Schenectady, N.Y. In 1894 he became professor of sociology at Columbia, where he earned a rep...