It’s almost certainly not an extraterrestrial telegram. But waves that seemed to come from the vicinity of Proxima Centauri will help astronomers refine their search techniques.
Astronomers searching for signs of life beyond Earth have spotted something strange. An as-yet unexplained radio signal appears to be coming from the direction of the star closest to the sun—a small red star roughly 4.2 light-years away called Proxima Centauri. Adding to the excitement, at least two planets orbit this star, one of which might be temperate and rocky like Earth.
Breakthrough Listen, a decade-long search for alien broadcasts from the nearest million stars, was using Australia’s Parkes Observatory to study Proxima Centauri when the team detected the conspicuous signal, which they dubbed BLC-1. The radio waves were picked up in observations made between April and May 2019.
“It’s pretty expected that every now and then you’ll see something weird, but this is interesting because it’s something that’s weird that we’re having to think about the next steps,” says Sofia Sheikh, a graduate student at Pennsylvania State University and the Breakthrough team member leading the signal analysis.
Though Sheikh and others strongly suspect that the signal is really human in origin, BLC-1 is the most tantalizing detection Breakthrough has made so far in its search for extraterrestrial intelligence, or SETI. The team is preparing two papers describing the signal and a follow-up analysis, which isn’t yet complete. (The detection was leaked to The Guardian before the research was ready for publication.)
While researchers continue to analyze the signal—and experts caution that there is almost certainly an ordinary, terrestrial explanation—even a remote hint of life beyond Earth has people excited.
“There’s a lot of talk about sensationalism in SETI,” says Andrew Siemion, Breakthrough Listen’s principal investigator. “The reason we’re so excited about SETI, and why we dedicate our careers to it, is the same reason why the public gets so excited about it. It’s aliens! It’s awesome!”
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