'The most massive known black hole in the universe has been discovered,
weighing in with the mass of 18 billion Suns. Observing the orbit of a
smaller black hole around this monster has allowed astronomers to test
Einstein's theory of general relativity with stronger gravitational fields
than ever before.
The black hole is about six times as massive as the previous record holder
and in fact weighs as much as a small galaxy. It lurks 3.5 billion light
years away, and forms the heart of a quasar called OJ287. A quasar is an
extremely bright object in which matter spiralling into a giant black hole
emits copious amounts of radiation.'
