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Last updated on April 16, 2014 at 21:23 EDT

Astrobiology Glossary Q – Space

Term Definition
Quark A basic building block of protons, neutrons, and other elementary particles.
Quasar The brightest type of active galactic nucleus, believed to be powered by a supermassive black hole. The word ‘quasar’ is derived from quasi-stellar radio source, because this type of object was first identified as a kind of radio source. Quasars also are called quasi-stellar objects (QSOs). Thousands of quasars have been observed, all at extreme distances from our galaxy.