Astronomers have been looking for signals from other civilizations for more than 60 years. They haven’t found any — at least none they can confirm. But 45 years ago today, they heard one that generated a lot of excitement: the “wow” signal. Astronomers at Ohio State were using a radio telescope to scan for evidence of extraterrestrial intelligence. And they found one signal that seemed to fit all the criteria. It was strong, it had a narrow bandwidth, and it was at the right frequency. The signal lasted for 72 seconds — the longest the telescope could scan any specific object. So the signal probably was longer than that. It was recorded on a paper graph. And when the observatory director saw it, he wrote “Wow!” beside it. But when the telescope looked for the signal again the next night, it got nothing. There was nothing on the following nights, either. And no one has heard a peep since then. It’s not for a lack of trying. Many observatories scanned that region of space soon after the
