Quasars Don't Last Long. So How Do They Get So Massive?

One of the unanswered questions in astronomy is just how supermassive black holes grew so big, so quickly. A team of astronomers have tried to answer this question by searching for actively feeding supermassive black holes (aka quasars) as a way to measure how much material material they are actually accumulating. They studied nebulae near the quasars that light up with the quasar is releasing radiation and found that many of the more distant quasars have only been active for a few hundred thousand years, not long enough to grow to the size we see today.