Killers of the Cosmos

Earth is hit by 100 tons of rock from space every day. Most burn up in the atmosphere, but a single rock wiped out the dinosaurs. Could it happen again?

More than 100 million pieces of small space debris are floating around the Earth. A big collision between two of these objects in low Earth orbit could be catastrophic.

Black holes were only theoretical until recently. And there are probably millions of them in the galaxy. Worse still, some are rogue, speeding through space with the potential to be lethal to Earth.