Why astronomers are interested in this mysterious signal

In the 1997 movie "Contact," a scientist, played by actress Jodie Foster, detects a radio signal -- the first communication from an extraterrestrial civilization. That story, penned by Carl Sagan and his wife Ann Druyan, is fiction of course. But the search for such a signal is not such a crazy story. Real scientists look to the sky, using powerful radio telescopes, hoping to hear even a faint whisper of a radio signal from of one our celestial neighbors.