30 years ago astronomer Jerry Ehman was looking over a printout of radio data from Ohio State University's Big Ear Radio Observatory when he saw a string of code so remarkable that he had to circle it and scribble "Wow!" in the margin. The printout recorded an anomalous signal so strong that it had to come from an extraordinary source.
Was it a burst of human-made interference? Or an alien broadcast from the stars? No one knows. The source of the "Wow" signal has never been heard from again - even though astronomers have looked for it dozens of times.
Now the SETI Institute is gearing up to look for it one more time, using the latest tool for seeking signals from extraterrestrial civilizations: the Allen Telescope Array in California.
More Here