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quantum electrodynamics

(Encyclopedia)quantum electrodynamics (QED), quantum field theory that describes the properties of electromagnetic radiation and its interaction with electrically charged matter in the framework of quantum theory. ...

sunspots

(Encyclopedia)sunspots, dark, usually irregularly shaped spots on the sun's surface that are actually solar magnetic storms. The spots are darker because the temperature of the spots is lower than that of the surro...

Mars, in astronomy

(Encyclopedia)Mars, in astronomy, 4th planet from the sun, with an orbit next in order beyond that of the earth. Mars has two natural satellites, discovered by Asaph Hall in 1877. The innermost of these, Phobos...

moon

(Encyclopedia)CE5 The moon: Near side CE5 The moon: Far side moon, natural satellite of a planet (see satellite, natural) or dwarf planet, in particular, the single natural satellite of the earth. It is no...

Keats, John

(Encyclopedia)Keats, John, 1795–1821, English poet, b. London. He is considered one of the greatest of English poets. The son of a livery stable keeper, Keats attended school at Enfield, where he became the frien...

National Association for the Advancement of Colored People

(Encyclopedia)National Association for the Advancement of Colored People (NAACP), organization composed mainly of American blacks, but with many white members, whose goal is the end of racial discrimination and seg...

antelope

(Encyclopedia)antelope, name applied to any of a large number of hoofed, ruminant mammals of the cattle family (Bovidae), which also includes the bison, buffalo, sheep, and goats. Found in Africa and Eurasia, they ...

equatorial coordinate system

(Encyclopedia)CE5 Equatorial coordinate system equatorial coordinate system, the most commonly used astronomical coordinate system for indicating the positions of stars or other celestial objects on the celesti...

Hubble's law

(Encyclopedia)Hubble's law, in astronomy, statement that the distances between galaxies (see galaxy) or clusters of galaxies are continuously increasing and that therefore the universe is expanding. Hubble's law ...

Delacroix, Eugène

(Encyclopedia)Delacroix, Eugène (Ferdinand-Victor-Eugène Delacroix) fĕrdēnäNˈ-vēktôrˈ-özhĕnˈ dəläkrwäˈ [key], 1798–1863, French painter. Delacroix is considered the foremost painter of the romanti...