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.
The upcoming 10YSS symposium will focus on both the pragmatic and more theoretical elements of such a discovery: How do we find Earth 2.0? How do we confirm evidence of life? If we find evidence of intelligent life out there, how do we announce it to the world? How will the people of Earth 1.0 react?
“How do you finally decide, ‘Eureka, we found it?’” said Mae Jemison, a former NASA astronaut and the principal for 100YSS. “What are the compelling signs of finding another planet outside of our solar system that indisputably is terrestrially evolved, with earth-like evolved lifeforms? … What would happen if we could identify it [as Earth 2.0]? How does that change us?”
Jill Tarter, a former director of the Center for SETI Research who was present at the Green Bank observatory during the 1997 incident, said the first and most important step is to verify that a suspected signal from an intelligent source is indeed from another star system. “We worry, being in California, about all those post-graduates and Caltech students deliberately trying to fool us simply because they can,” said Tarter. Before any public announcement, “it should get verified independently” so as not to undermine SETI’s credibility.
The radio signal they’re looking for will stand out from cosmic radiation background noise—but so do signals from satellites, ground interference, and possibly natural but unknown astronomical phenomenon. If the signal occupies only a narrow band of frequencies, however, that separates it from natural cosmic emissions, suggesting a deliberate signal. Turning the radio telescope’s dish slightly from the signal’s apparent source can determine its distance: If the source is nearby, the signal will slowly fade. If it’s coming from a distant star, the signal will drop off sharply.
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SOURCE: The Atlantic, Tom Chmielewski