Radio waves haven't turned up any signs of alien life, so astronomers are widening the spectrum of their search to include near-infrared light.
Even if we do establish contact with extraterrestrials, communicating with them is a whole other story.
Scientists search for narrow-band transmissions in outer space as a possible sign of extraterrestrial life.
E. T. phoned. Now what? Learn about the earth's response to alien contact on this Moment of Science.
If E.T. does try to phone us how will we know it? Find out on this Moment of Science.