Astronomers recently discovered the most massive black holes to date. Found in two separate nearby galaxies roughly 300 million light years away from Earth, each black hole has a mass equivalent to 10 billion suns.
"We knew that really large quasars, which are powered by matter falling into black holes, existed in the early universe," said Chung-Pei Ma, an astrophysicist at the University of California, Berkeley and co-author of an article that will be published in Nature on December 8.