Asteroids have a bad reputation as deadly rocks from space. They wiped out the dinosaurs and will be back for us. But that's only half the story. Ancient asteroids built the Earth. And they may have brought life to its barren surface. Asteroids will shape our future as much as our past. They are the perfect location for deep space colonies and could be the stepping stones that eventually send humans out into the cosmos. From icy worlds with more fresh water than Earth to flying mountains of pure metal, a hundred miles wide, scientists are striving to unlock their secrets. Could these enigmatic space rocks hold the key to how life in the Universe arises and is extinguished?
In 2014, the International Space Station had to move three times to avoid lethal chunks of space debris and there is an increasing problem of satellites mysteriously breaking down. With first-hand accounts from astronauts and experts, Horizon reveals the scale of the problem of space junk. Our planet is surrounded by hundreds of millions of pieces of junk moving at 17,000 miles per hour. Now the US government is investing a billion dollars to track them, and companies around the world are developing ways to clear up their mess - from robot arms to nets and harpoons. Horizon investigates the science behind the hit film Gravity and discovers the reality is far more worrying than the Hollywood fiction.
The Moon has drawn out our sense of wonder since before we were fully human. Where did it come from? What secrets are written in its rocks? For most of our history, its story was cloaked in myth and mystery. Only now are the vivid details coming into focus.
We reveal the planetary enigmas on our doorstep and embark on the New Horizons voyage to photograph Pluto. Will our encounter with this tiny ball of ice and rock and the trillions of icy objects beyond it paint a clearer picture of how the planets came to be?