The question of whether there is intelligent life elsewhere in the universehas been asked by people for many years.
But if we hear something, should we answer? In the absence of any signal from them, should we try to make our presence known?
One of those asking these questions is Stephen Hawking, the British cosmologist with many deep thoughts and a good sense of humour.
Unlike many celebrity scientists, Hawking’s provocative, news-grabbing statements almost always have some content worth pondering.