LONDON (Reuters) - An unexplained radio signal from deep space could -- just might be -- contact from an alien civilisation, New Scientist magazine has reported. The signal, coming from a point between the Pisces and Aries constellations, has been picked up three times by a telescope in Puerto Rico. New Scientist said on Thursday the signal could be generated by a previously unknown astronomical phenomenon or even be a by-product from the telescope itself. But the mystery beam has excited astronomers across the world. "If they can see it four, five or six times it really begins to get...