Alien signals? Massive radio telescope pointed at 'alien megastructure' star

The Green Bank Telescope is the largest moveable radio telescope of its kind, and it hopes to find out if flickering from 'Tabby's Star' is indicative of alien activity. 

KIC 8462852 is one of the most unusual stars ever spotted in the night sky.

It was discovered as early as the 1980s, but it remained quietly out of the limelight until September 2015, when Tabetha S. Boyajian, then a postdoctoral researcher at Yale University, published a study highlighting something unusual going on with the KIC 8462852. The star was flickering in a way that had never been observed before, with massive dips in luminosity that couldn't be explained by conventional means.

The star, which became known as Tabby's Star after Dr. Boyajian's paper was published, has become one of the most intriguing astronomical mysteries in the night sky. While scientists still suspect that the mysterious flickering has some kind of natural explanation, one theory that seems to fit the facts of the case is that Tabby's Star may be surrounded by orbiting pieces of alien technology. In order to test the extraordinary hypothesis, West Virginia’s Green Bank Telescope will spend the next two months gathering a massive amount of data on the star in an attempt to detect signs of an alien civilization.

The telescope is part of the Breakthrough Listen project, which began in January of this year. The $100 million initiative aims to bring the most advanced equipment and cutting-edge technology to conduct a more comprehensive sweep of the night sky for signs of alien civilizations. The project is giving special priority to Tabby's Star due to its unusual flickering.

"The Breakthrough Listen program has the most powerful SETI equipment on the planet, and access to the largest telescopes on the planet," said Andrew Siemion, director of the Berkeley Search for Extraterrestrial Intelligence (SETI) Research Center and co-director of Breakthrough Listen, in a statement. "We can look at it with greater sensitivity and for a wider range of signal types than any other experiment in the world."

That's where the Green Bank Telescope comes in. The device is the largest moveable radio telescope of its kind, with a 330-foot parabolic dish. According to the Washington Post, the telescope will commit to three eight-hour nights of observation over the next two months gathering about a petabyte (a million gigabytes) of data. The telescope spent the early hours of Thursday morning monitoring transmissions from the star on the spectra associated with human technology, from about 1 to 12 gigahertz.

While a large amount of resources has been committed to the search for alien technology around Tabby's Star, scientists are quick to emphasize that the chances of finding proof of an extraterrestrial civilization are minimal.

"Everyone, every SETI program telescope, I mean every astronomer that has any kind of telescope in any wavelength that can see Tabby’s star has looked at it," said Dr. Siemon in the statement. "It's been looked at with Hubble, it's been looked at with Keck, it's been looked at in the infrared and radio and high energy, and every possible thing you can imagine, including a whole range of SETI experiments. Nothing has been found."

So why look at the star at all?

For starters, even if aliens are not responsible, scientists still don't know the cause of the flickering. Astronomers identify exoplanets based on dips in luminosity as the planets pass between their star and observation points on Earth, but generally, these dips are tiny and regular. Even a planet the size of Jupiter would only block about 1 percent of a star's light.

But there are hundreds of dips around Tabby's Star, some happening at irregular intervals, and some blocking as much as 15 and 22 percent of the light from the star. While this could theoretically be due to debris from some sort of planetary-scale collision, astronomers would expect infrared light to be present in the aftermath of such a collusion, which is not the case. A better explanation might be a swarm of comets crossing in front of Tabby's Star, but many scientists have their doubts about that explanation as well.

"When [Boyajian] showed me the data, I was fascinated by how crazy it looked," Wright told The Atlantic last year. "Aliens should always be the very last hypothesis you consider, but this looked like something you would expect an alien civilization to build."

The alien superstructure that could explain the light dips could be some sort of Dyson swarm or similar structure. A Dyson swarm is a theoretical structure that consists of a mass of solar panels or similar technology in orbit around a star, harvesting energy on an efficiency scale far greater than humans are currently able to accomplish.

It is also possible that these flickers are something else entirely. As the Monitor previously reported in an article about alien civilization searching techniques, gamma ray bursts were thought to be alien signals when they were first imaged in 1997, but they turned out to be a natural by-product of supernovae.

"I don't think it's very likely [this is an alien superstructure] – a one in a billion chance or something like that – but nevertheless, we're going to check it out," said Dan Werthimer, chief scientist at Berkeley SETI, in the statement. "But I think that ET, if it’s ever discovered, it might be something like that. It'll be some bizarre thing that somebody finds by accident … that nobody expected, and then we look more carefully and we say, 'Hey, that’s a civilization.'"