The false alarm happened in 1997.
The Green Bank Radio Observatory in Green Bank, West Virginia, was picking up some unusual signals—and Seth Shostak, then the head of the Center for Search for Extraterrestrial Intelligence (SETI) Research in Mountain View, Caifornia, was convinced that they had come from intelligent life somewhere in the universe.
“It looked like it might be the real deal,” Shostak recalled. Within a few hours, he had a call from The New York Times.
But within a day, it became clear that the source of excitement was actually a European satellite. To make matters worse, a second telescope in Georgia, which would have told the scientists about the true nature of the signal, wasn’t working.
Yet Shostak says that false alarm proved to be a valuable dry run for the astronomers, giving them a small taste of what would happen if the signal turned out to be real. In 1989, the International Academy of Astronautics adopted its SETI Post-Detection Protocols, a set of guidelines for how to proceed once intelligent life is discovered among the stars. SETI researchers hope that one day soon, they’ll have a chance to use them.
Later this month, the 100-Year Starship Project (100YSS), a NASA-funded initiative dedicated to achieving interstellar travel within the next century, will discuss the lessons to be learned from the 1997 incident during its annual symposium, this year with the theme “Finding Earth 2.0.”
Since the first exoplanet was identified in 1992, astronomers have confirmed the existence of nearly 1,900 planets beyond our solar system. The sheer number of planets increases the statistical probability that Earth-like planets will be found. Some estimate that there are around 140 habitable planets in our stellar neighborhood within 33.6 light years of Earth. Many astronomers estimate that we’ll find a life-bearing planet within 25 to 30 years, or maybe tonight, if we know what to look for.