The Active Galactic Nucleus

The active galactic nucleus is, as its name implies, the nucleus of a galaxy. It's at its core, a supermassive black hole, and around it, it's stuff falling into it. The moment that all astronomers came to the consensus that what you described was correct came from the groundbreaking study led by John Bacall using the Hubble Space Telescope. One of my favorite versions of personal astrophysicist Neil DeGratas' Star Talkm Aquarius grab bag will be over next few days.