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?

A spy satellite chances on a threat from deep space. When a massive star dies, it can direct a blast of radiation that would obliterate life on Earth. What are the chances of this event occurring?

More than 100 million pieces of small space debris are floating around the Earth. A collision between two of these objects in low Earth orbit could be catastrophic. It could set off a chain reaction leading to a global communication meltdown.

If they exist, aliens could be killers who want to invade and plunder Earth. A team of experts investigate extra-terrestrial beings and their threat to human life.

Until recently, black holes were only theoretical. Scientists know that millions exist. Worse still, some are rogue, speeding through space with the potential to destroy Earth.

Everything comes to an end, even a universe. So, how will it all end? Will gravity make it collapse, or will it expand forever? Experts discuss the many possible ways that could spark the beginning of the end for the universe, including when and why it would happen.