Discovered in the early 1960s, quasars are highly luminous objects shining over vast intergalactic distances. Until the early 1980s, the nature of quasars was controversial, but now most astronomers agree a quasar is a supermassive black hole in the center of a distant massive galaxy. The black hole rapidly accretes (accumulates) matter toward its center to create a quasar’s powerful luminosity. Still, mysteries about quasars have remained, and now two scientists say they’ve solved a quasar mystery that astronomers have been puzzling over for 20 years. These scientists say that most observed quasar phenomena can be unified with two simple quantities: how efficiently the central black hole is being fed and the viewing orientation of the astronomer. The journal Nature published this work on September 11, 2014.
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