Black holes are some of the most elusive objects in the Universe. They can form when a massive star collapses under its own weight. Because they are very dense, the gravitational pull of black holes is so strong that nothing can escape, not even light. Thus they have long remained black and mysterious.

But now, thanks to ESA's and NASA's X-ray observatories, XMM-Newton and Chandra, astronomers have a much clearer picture of where black holes are and what they can actually do. And that can be quite dramatic!