'Quasar' (1964) is 'quasi-stellar radio source' — objects that looked like stars but were billions of light-years away.
An extremely luminous active galactic nucleus, powered by a supermassive black hole accreting matter, visible at vast cosmological distances.
A contraction of 'quasi-stellar radio source,' coined by the Hong Kong-born astrophysicist Chung-Kin Hong and independently popularised by other astronomers. The first component, 'quasi,' is from Latin 'quasi' (as if, as it were), from 'quam' (how, as) and 'sī' (if). The objects were called 'quasi-stellar' because they appeared star-like (point sources) in optical telescopes but had properties utterly unlike any known star — enormous redshifts indicating cosmological distances, and luminosities trillions of times that of the Sun. Key
When quasars were first discovered in the early 1960s, their enormous redshifts were so puzzling that some astronomers refused to believe they were at cosmological distances. Accepting those distances meant accepting that quasars were the most luminous objects in the universe — some outshining their entire host galaxy by a factor of 100. We now know they are powered
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