Last month, as 2020 drew to a close and we on Earth completed one of our strangest orbits around the sun, news broke that astronomers had picked up a mysterious signal from another star.

Astronomers could tell, from the specific properties of the beam of radio waves, that it wasn’t made by an act of nature, such as a cosmic explosion. The signal coming from the star’s direction was produced by technology.

The signal, known as BLC1, was intriguing, but when news of its detection leaked to The Guardian, the astronomers who detected it—and others in the field—were quick to point out that although the transmission came from some kind of technology, the technology probably belonged to us. In the weeks since the news emerged, the researchers have done more work, and they believe that although the signal is artificial, it’s probably not the work of aliens.

“There’s nothing about it that says it’s clearly some alien intelligence trying to send us a message,” Sofia Sheikh, a graduate student at Pennsylvania State University who is leading the team studying the signal, told me recently. Sheikh is a member of Breakthrough Listen, a program funded by a Russian billionaire that searches for evidence of alien communications. “There’s no information carried in the signal. It’s just a single tone, like a foghorn. In fact, it looks very much like the things we produce on Earth.”

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