Tabby’s star (officially designated as KIC 846285), or as most of us know it, the star straight out of a sci-fi movie. Did a highly advanced civilization build a massive structure around it? That’s one theory. Why? Because Tabby’s star sees a stunning drop in its light output that can’t be explained by a transiting planet.

Take your average star with an orbiting exoplanet. It might dim its host star 1 or 2 percent when it passes between its star and the telescope observing it. And these dimming periods happen at regular intervals. What has astronomers scratching their heads with Tabby’s star is it dims as much as 22 percent. For days at a time and at various intervals.

A more plausible theory pointed the finger at a swarm of comets breaking up as it approached the star. Follow-up observations nixed that idea. The star also appears to be in the midst of a century-long dimming phase.

Then, speculation popped up suggesting a Dyson sphere. An artificial structure used to harness the power of a star. Basically, a civilization becomes so advanced it needs to use the power of its nearby star to power itself.

Is it possible? Hell, anything is possible. The chances of us stumbling on a civilization like this are incredibly small, but SETI can’t pass any opportunity up.

“I don’t think it’s very likely – a one in a billion chance or something like that – but nevertheless, we’re going to check it out,” said Dan Werthimer, a chief scientist at Berkeley SETI. But Werthimer thinks our first discovery of ET will probably go something like this. “It’ll be some bizarre thing that somebody finds by accident … that nobody expected, and then we look more closely and we say, ‘Hey, that’s a civilization.’”

Bottom line? Tabby’s star dims drastically at random points and is slowly dimming. Both phenomena have astronomers scratching their heads.

A job for the Green Bank Telescope

UC Berkeley’s Breakthrough Listen project will harness the power of the Green Bank Telescope to hopefully shed some light on the Tabby’s star’s strange light dimming.

Sitting in the quiet hills of Green Bank, West Virginia, the Green Bank Telescope is the largest fully steerable radio telescope on the planet.

“We’ve deployed a fantastic new SETI instrument that connects to that telescope, that can look at many gigahertz of bandwidth simultaneously and many, many billions of different radio channels all at the same time so we can explore the radio spectrum very, very quickly,” says Andrew Siemion, the director of the Berkeley SETI Research Center.

More than likely, Green Bank will confirm what every other telescope has. From the Hubble to Keck and every properly equipped telescope in between, star observations come back the same. No ET signals coming from Tabby’s star.

Members of the Breakthrough Listen project began observations of Tabby’s star last night. The telescope’s massive radio dish tracked the star across the night’s sky for eight hours. Observations will continue across two more nights over the next two months with about one petabyte of data expected to be gathered. That enormous amount of data will stretch across millions of individual radio channels.

Yep, Green Bank is going to need some big hard drives. A petabyte is just over a thousand terabytes, or a million gigabytes.

Alien megastructure, or something less exciting? The answer will probably lie in a petabyte worth of data. Yeah, I hope SETI wrote some programs to sift through all that data.

Tabby’s star is weird. There’s no denying that. The question is, how weird? Weird as in we haven’t seen this kind of natural phenomena before. Or, weird as in we need to call Harry Stamper, David Levinson and Luke Skywalker asap.

SETI began answering that last night.

UPDATE: Clarified the article’s title.