Adjacent Words

quasar definitions

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WordNet (r) 3.0 (2005)

n
1: a starlike object that may send out radio waves and other forms of energy; many have large red shifts [syn: quasar, quasi-stellar radio source]

Merriam Webster's

noun Etymology: quasi-stellar Date: 1964 any of a class of celestial objects that resemble stars but whose large redshift and apparent brightness imply extreme distance and huge energy output

Britannica Concise

Any of a class of rare cosmic objects of high luminosity and strong radio emission observed at extremely great distances. The term is also often applied to closely related objects that have the same optical appearance but do not emit radio waves, the so-called QSOs (quasi-stellar objects). Most quasars exhibit very large red shifts, suggesting that they are moving away from earth at tremendous speeds (approaching the speed of light) and are some of the most distant known objects in the universe. Quasars are no more than a light-year or two across but up to 1,000 times more luminous than a giant galaxy with a diameter of 100,000 light-years, allowing them to be observed at distances of more than 10 billion light-years. Many investigators attribute such energy generation to gas spiraling at high velocity into a supermassive black hole at the center of an otherwise normal galaxy. See also active galactic nuclei.

Oxford Reference Dictionary

n. Astron. any of a class of starlike celestial objects having a spectrum with a large red-shift. Etymology: quasi-stellar

Collin's Cobuild Dictionary

(quasars) A quasar is an object far away in space that produces bright light and radio waves. N-COUNT

Moby Thesaurus

Beehive, Cepheid variable, Hertzsprung-Russell diagram, Hyades, Messier catalog, NGC, Pleiades, Seven Sisters, absolute magnitude, binary star, black hole, double star, dwarf star, fixed star, giant star, globular cluster, gravity star, magnitude, main sequence star, mass-luminosity law, neutron star, nova, open cluster, populations, pulsar, quasi-stellar radio source, radio star, red giant star, relative magnitude, sky atlas, spectrum-luminosity diagram, star, star catalog, star chart, star cloud, star cluster, stellar magnitude, supernova, variable star, white dwarf star