Cosmologists answer questions about the shape and size of the cosmos, and how, by decoding radiation from the dawn of time - 15 billion years ago - they can discover the limits and the ultimate destiny of the Universe.
This film tells of hostile new worlds that have been discovered on the edge of the Universe and explores the tantalizing possibility of one day finding a planet like Earth.
A look at how our solar system is teeming with thousands of asteroids and comets, it is now thought these mini-worlds played a vital part in kick-starting life on our planet.