We go in search of ET. We ponder big questions like where could ET be hiding? What could he look like? When might we find him? What would we say to him if we did make ‘contact’? What would be the consequences on Earth of ET phoning us?

With Dr Andrew Shearer, NUI Galway; Jerry Ehman; SETI astronomer Seth Shostak; astronomer Paul Davies; astronaut Paolo Nespoli.