In August, Russian astronomers announced that they had detected a blast of radio waves coming from the direction of the star HD164595, 94 light years away. Maybe, they said, the blast came from aliens in orbit. Headlines breathlessly speculated about extraterrestrials, and other telescopes around the world swung to look at the same star, trying to catch the signal.
But these scientists had actually picked the radio waves up in May 2015—they had just kept it quiet for more than a year. Partly because of that delay, other astronomers were unable to distinguish between possibilities mundane and spectacular. Had a hypothetical extraterrestrial broadcast gone offline, or was the signal a fluke—some spike from inside the Russian observatory itself, or a satellite passing overhead (most likely)?
SETI as a field has ways to combat these ambiguities—so that if scientists find a candidate extraterrestrial signal, they will be able to identify it right away and rule out terrestrial interference. But the world’s newest and best-heeled SETI search, the Breakthrough Listen project, may be vulnerable to the some of the same problems the Russian scientists faced.
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