'Alien Megastructure' Theory Collapses in a Cloud of Dust

Something is intermittently obscuring light from the ‘most mysterious star in the universe’ – but not, it seems, a planet-sized artifact made by aliens orbiting Tabby’s Star

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A hypothetical uneven ring of dust orbiting KIC 8462852, also known as Boyajian's Star or Tabby's Star: Illustration
A hypothetical uneven ring of dust orbiting KIC 8462852, also known as Boyajian's Star or Tabby's Star: IllustrationCredit: NASA/JPL-Caltech

The “most mysterious star in the universe” just lost some of its cachet after scientists decided that the anomalies observed in “Tabby’s Star” are likely not caused by a gigantic alien artifact orbiting the star and intermittently blocking its light.

Tabby’s Star is really named KIC 8462852, but thankfully it was nicknamed after Tabetha Boyajian, an assistant professor at Louisiana State University. It’s about 50 percent bigger than our sun and, say the scientists, 1,000 degrees hotter. There is nothing whatsoever remarkable about it, say astronomers, except that it dimmed and brightened sporadically, like no other star.

One theory to explain the anomalies in emission patterns was that aliens had built a vast megastructure that orbits the star. They would have had to build the structure over 1,000 years ago, since that’s how long it takes rays from Tabby’s Star to reach Earth.

The snag is that there is zero evidence that aliens exist, while other theories are possible that could explain the star’s unusual patterns, based on things we do know exist. Such as, the remains of a shattered planet, a cluster of comets, and more.

Anyway, it’s probably the tenuous alien connection that persuaded more than 1,700 people to donate $100,000-plus to a Kickstarter campaign to fund watching Tabby’s Star through telescopes.

The result is reams of data, now published by Tabby Boyajian and the team in partnership with the Las Cumbres Observatory in the Astrophysical Journal Letters.

Based on the data, the team has downgraded the exotic alien artifact theory in favor of the humdrum postulation that they can’t see the light sometimes because of a dust cloud. It’s not unlike why Israelis sometimes can’t see the sun during the day because sand is blowing in from the Sahara.

“Dust is most likely the reason why the star’s light appears to dim and brighten,” explains Boyajian. “The new data shows that different colors of light are being blocked at different intensities. Therefore, whatever is passing between us and the star is not opaque, as would be expected from a planet or alien megastructure.”

Now you see Tabby’s anomaly, now you don’t

Citizen scientists called “Planet Hunters” were the ones who first noticed Tabby’s anomalies, while volunteering to help NASA by sifting through the mountains of data.

From March 2016 to December 2017, there were four distinct episodes when the star’s light dimmed. Given the opportunity to vote on names for the episodes, the crowdfunders named the first two Elsie and Celeste, and the last two Skara Brae and Angkor – names of lost cities in Scotland and Cambodia, respectively. (Why? Simply because, like those cities, this star is mysterious.)

The authors write that in many ways what is happening with the star is like these lost cities: they’re old and shrouded in mystery.

“They’re ancient; we are watching things that happened more than 1,000 years ago,” wrote the authors. “They’re almost certainly caused by something ordinary, at least on a cosmic scale. And yet that makes them more interesting, not less. But most of all, they’re mysterious.”

But it seems that if Tabby’s Star is shrouded in anything, it’s just dust.