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Montezuma
Montezuma or Moctezuma , 1480?-1520, Aztec emperor (c.1502-1520). He is sometimes called Montezuma II to distinguish him from Montezuma I (ruled 1440-69), who carried on conquests around Tenochtitlán . His reign was marked by incessant warfare, and his despotic rule caused grave unrest. ...
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airglow
airglow faint diffuse illumination of the night sky originating in the upper atmosphere. The energy in the form of visible light is derived from the sun's ultraviolet light, which ionizes atoms and dissociates molecules at heights between 40 and 200 mi (64-322 km) above the earth's surface. When th...
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Quetzalcoatl
Quetzalcoatl [Nahuatl,=feathered serpent], ancient deity and legendary ruler of the Toltec in Mexico. The name is also that of a Toltec ruler, who is credited with the discovery of corn, the arts, science, and the calendar. It is unclear whether the ruler took his name from the god or as a great ...
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interstellar matter
interstellar matter matter in a galaxy between the stars, known also as the interstellar medium.
Distribution of Interstellar Matter
Compared to the size of an entire galaxy, stars are virtually points, so that the region occupied by the interstellar matter constitutes nearly all the ph...
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polarization of light
polarization of light orientation of the vibration pattern of light waves in a singular plane.
Characteristics of Polarization
Polarization is a phenomenon peculiar to transverse waves, i.e., waves that vibrate in a direction perpendicular to their direction of propagation. Light is a tra...
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Gordon W. Allport
Gordon W. Allport , 1897-1967, American psychologist, b. Montezuma, Ind. One of the first psychologists to study personality , Allport researched human attitudes, prejudices, and religious beliefs. His theory of personality, which rejected both Freudian psychology and behaviorism, emphasized the un...
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Carl Heinrich Graun
Carl Heinrich Graun , 1704-59, German composer, best known for his oratorio Der Tod Jesu (1755), for many years performed annually in Germany. As musical director to Frederick the Great, who wrote the libretto of Graun's Montezuma (1755), he was also director of the opera at Berlin, where his ow...
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planet
planet [Gr.,=wanderer], a large nonluminous ball of rock or gas that orbits a star. The term, once limited to any of the eight solid, nonluminous bodies (major planets) that revolve around the sun, has been extended to include similar bodies discovered revolving around other stars. The term is some...
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optical activity
optical activity the ability of asymmetric compounds to rotate the orientation of planar polarized light. Such compounds and their mirror images are know as enantiomers, or optical isomers. Although differing in geometric arrangement, enantiomers possess identical chemical and physical properties. ...
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polar front
polar front zone of transition between polar and tropical air masses . Its average position during the winter is at about 30° lat. and during the summer at about 60° lat. In the N Atlantic Ocean, for example, the polar front can often be traced as a continuous line extending over thousands...
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