OJ287: Really, really BIG!

The most massive black hole known, has been discovered -- weighing in at a massive 18-billion Suns. And it gets better. This black hole is so massive, it has another black hole, weighing about 100-million Suns, orbiting it. The smaller black hole makes a complete orbit of the larger one every 12 years, ploughing through its accretion disk twice during an orbit. Each time the smaller black hole moves through the larger's accretion disk, huge outbursts of radiation is released, causing the system to brighten. The two black holes form the heart of the quasar QJ287. As general relativity predicts, astronomers have observed the decay of the smaller black hole's orbit. At the rate of decay, the smaller black hole will be swallowed by the larger in 10,000 years.