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radio astronomy

(Encyclopedia)radio astronomy, study of celestial bodies by means of the electromagnetic radio frequency waves they emit and absorb naturally. Radio waves also come from outside the Milky Way. These extragalact...

stellar evolution

(Encyclopedia)CE5 The above Hertzsprung-Russell (H-R) diagram shows the track of stellar evolution for a typical star. After spending much of its life evolving toward or along the main sequence, the star becomes...

dictionary

(Encyclopedia)dictionary, published list, in alphabetical order, of the words of a language. In monolingual dictionaries the words are explained and defined in the same language; in bilingual dictionaries they are ...

snake, in zoology

(Encyclopedia)snake, common name for an elongated, limbless reptile of the order Squamata, which also includes the xlizards. Most snakes live on the ground, but some are burrowers, arboreal, or aquatic; one group i...

black hole

(Encyclopedia)black hole, in astronomy, celestial object of such extremely intense gravity that it attracts everything near it and in some instances prevents everything, including light, from escaping. The term was...

science

(Encyclopedia)science [Lat. scientia=knowledge]. For many the term science refers to the organized body of knowledge concerning the physical world, both animate and inanimate, but a proper definition would also hav...

dating

(Encyclopedia)dating, the determination of the age of an object, of a natural phenomenon, or of a series of events. There are two basic types of dating methods, relative and absolute. In relative dating, the tempor...

radioactivity

(Encyclopedia)CE5 Effects of a magnetic field on the products of radioactivity CE5 Disintegration series: Radioactive decay of radium-226 into lead-206 radioactivity, spontaneous disintegration or decay of t...

surgery

(Encyclopedia)surgery, branch of medicine concerned with the diagnosis and treatment of injuries and the excision and repair of pathological conditions by means of operative procedures (see also anesthesia; medicin...

physics

(Encyclopedia)physics, branch of science traditionally defined as the study of matter, energy, and the relation between them; it was called natural philosophy until the late 19th cent. and is still known by this na...