Supermassive black holes

In addition to black holes created through stellar collapse, evidence suggests that supermassive black holes, millions or even billions of solar masses, have been lurking in the centres of galaxies since early in the history of the universe. In the case of so-called active galaxies, the evidence for these heavyweights is spectacular.

The central black holes in these galaxies are surrounded by accretion discs that produce intense radiation at all wavelengths of light. We also have evidence that our own galaxy has a black hole at its centre. That’s because we see the stars in that region whizzing around so fast – up to eight per cent of the speed of light – that they must be orbiting something extremely small and massive.