Are We Alone?

S1 E3: We live in a galaxy with over 200 billion star systems, many of which will be home to planets which could support life. The question is: is there anybody there? After all, if the universe has thrown up one intelligent civilisation - us - why not more? Brian Cox investigates our human urge to contact alien intelligence, visiting the deserts of Northern California to join the hunt using the world's most sensitive alien hunting radio telescope.