Illustration of a Dyson sphere around a star
Illustration of a Dyson sphere around a star. Danielle Futselaar/SETI International

A mystery is circling around the star KIC 846285. Hundreds of light-years away, the star’s light dims by as much as 22 percent, and in erratic patterns. It can’t be a planet, so astronomers’ best guess is that a messy family of comets is blocking the light.

However, some scientists think it’s worth at least considering the possibility that technology built by aliens–a swarm of solar collectors, perhaps–could be orbiting and periodically eclipsing the star.

The scientists behind the alien hypothesis knew it was a long shot when they proposed it, and since then, telescopes have failed to find any alien signatures in the radio or infrared emissions coming from the star.

Now, a study published on the arXiv reports that researchers also haven’t detected any laser pulses coming from KIC 846285. For six nights, researchers from a new group called SETI International used the Boquete Optical SETI Observatory in Panama to look for the laser signals.

“If any hypothetical extraterrestrials had beamed intentional laser pulses in the visible spectrum toward Earth,” the group’s press release says, “the Boquete observatory could have detected them so long as they exceeded the observatory’s minimum detectable limit.”

That minimum limit was set pretty high. The telescope looked for nanosecond pulses, and could detect signals at 4,000,000,000,000 kilowatts or higher. For context, those lasers would need to be thousands of times more powerful than anything we have on Earth. But, if you’re an alien civilization building megastructures around stars, maybe that’s not such a big challenge.

“The hypothesis of an alien megastructure around KIC 8462852 is rapidly crumbling apart.”

SETI International notes that their lower threshold is high, but adds that if those laser signals are aimed anywhere in the general vicinity of Earth, they wouldn’t have to be quite so high.

“The hypothesis of an alien megastructure around KIC 8462852 is rapidly crumbling apart,” said Douglas Vakoch, president of SETI International and an author of the paper, said in a statement.

Nevertheless, KIC 8462852 is likely to remain in the spotlight for a while yet.

The problem with the alien hypothesis is that the scientific method isn’t always great at proving a thing doesn’t exist. There’s always the possibility of that we’re not asking the question properly, or looking for the right signals, or that our tools aren’t good enough to detect whatever it is we’re looking for.

Next year, the Green Bank radio telescope in West Virginia will turn its very large ear toward the mysterious star, and probably many other telescopes will perform their own studies in the meantime.