Trivia 2 ~ Answer 5 – A Supermassive Black Hole

A quasar is an extremely luminous active galactic nucleus, powered by a supermassive black hole, with mass ranging from millions to tens of billions of solar masses, surrounded by a gaseous accretion disc.

Gas in the disc falling towards the black hole heats up because of friction and releases energy in the form of electromagnetic radiation. The radiant energy of quasars is enormous; the most powerful quasars have luminosities thousands of times greater than a galaxy such as the Milky Way.

The term quasar originated as a contraction of “quasi-stellar [star-like] radio source”—because quasars were first identified during the 1950s as sources of radio-wave emission of unknown physical origin—and when identified in photographic images at visible wavelengths, they resembled faint, star-like points of light. High-resolution images of quasars, particularly from the Hubble Space Telescope, have demonstrated that quasars occur in the centers of galaxies and that some host galaxies are strongly interacting or merging galaxies.

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