The flame, meant to represent purity, was kindled from the rays of the sun using a parabolic mirror in a ceremony on 10 May at Olympia, the home of the ancient Olympic Games.

BBC: Olympic torch: Huge crowds turn out to cheer flame

It is the mirror that we hold up to the planet in our scientific search for the answer to the ancient question, 'Are we alone?

CNN: What if there's somebody else out there?