“Two possibilities exist: either we are alone in the Universe or we are not. Both are equally terrifying.” So said sci-fi author Arthur C Clarke. We’ve been fascinated by the idea life may exist elsewhere, and for over 50 years the Search for Extra Terrestrial Intelligence (Seti) has been scanning the galaxy for messages from an alien civilisation to no avail.
But the discovery of planets outside our solar system, or exoplanets, has raised hopes that efforts to contact alien lifeforms may one day succeed. BBC’s Horizon joined the planet hunters who discovered a new world called Gliese 581 c. To date, it is one of the most Earth-like planets found around another star, and it may have habitats capable of supporting life.