Astronomers using NASA’s Hubble Space Telescope have found that Markarian 231 (Mrk 231), the nearest galaxy to Earth that hosts a quasar, is powered by two central black holes furiously whirling about ...

Astronomers using NASA’s Hubble Space Telescope have found that Markarian 231 (Mrk 231), the nearest galaxy to Earth that hosts a quasar, is powered by two central black holes furiously whirling about ...

A University of Oklahoma astrophysicist and his Chinese collaborator have found two supermassive black holes in Markarian 231, the nearest quasar to Earth, using observations from NASA's Hubble Space ...

NASA’s Hubble Space Telescope has photographed a set of wispy, goblin-green objects that are the ephemeral ghosts of quasars that flickered to life and then faded. The glowing structures have looping, ...

Markarian 231 won't win any galactic beauty contests. Seen through the Hubble Space Telescope, it's a bit lopsided and dull. But boy, what a personality. This galaxy near the tail of the Big Dipper is ...