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?

When a massive star dies it can direct a blast of radiation that would obliterate life of earth. What are the chances of this event occurring?

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.

Aliens could be lethal killers who want to invade and plunder our world. A team of experts investigate extra-terrestrial beings and their threat to human life.

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.

How will the universe end? Experts discuss the many possible ways that could spark the beginning of the end for the universe including when and why it would happen.