Kepler's 'Alien Megastructure' Star to Spill SETI Secrets?
The Breakthrough Listen SETI project will aim one of the world's most powerful radio telescopes at Tabby's Star for three nights in the hope of detecting an alien civilization.
The star KIC 8462852 - informally known as Tabby's Star - has been the focus of the worlds' attention for months now, and for good reason. Its strange behavior could be a sign that there's a super-advanced alien civilization carrying out the mother of all engineering projects in orbit. But the mysterious dips in observed light from the star could alternatively just be a huge swarm of comets or some other as-yet-to-be-understood stellar phenomenon.
Although astronomers are generally skeptical that there really is an extraterrestrial civilization constructing a starlight-blocking megastructure only 1,480 light-years from Earth, the Breakthrough Listen SETI (Search for Extraterrestrial Intelligence) project is committing radio telescope time of one of the most powerful observatories on the planet to at least test the intelligent alien hypothesis.
The project is a part of the $100 million Breakthrough Prize Foundation that's funded by Russian entrepreneur Yuri Milner and backed by British theoretical physicist Stephen Hawking and Facebook founder Mark Zuckerberg.
Starting Wednesday (Oct. 26), a team of astronomers will use the renowned 100-meter Green Bank Telescope (pictured above) that is located deep in a radio-silent corner of West Virginia to study Tabby's Star. For eight hours per night for three nights over the next two months, a special instrument attached to the huge radio telescope will be used to carry out an unprecedented observation campaign of the star.
"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 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."
Although other projects have tried to eavesdrop on the star before, SETI campaigns have typically been limited by the number of radio frequencies that can be recorded simultaneously and the amount of time committed to just one star in the sky. This new instrument is able to record a huge amount of data across a range of frequencies at the same time, potentially allowing us to detect the radio transmissions from any transmitting intelligent aliens at Tabby's Star.
"The Green Bank Telescope is the largest fully steerable radio telescope on the planet, and it's the largest, most sensitive telescope that's capable of looking at Tabby's star given its position in the sky," said Siemion. "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."
It's estimated that up to one petabyte of data may be collected over the observing run - that's enough data to fill a thousand computer hard drives (assuming each can store one terabyte). The researchers say that it could be over a month before we know whether or not a signal was detected because it will take a long time to process all the observations.
With Siemion, Tabetha Boyajian, from Louisiana State University, and visiting UC Berkeley astronomer Jason Wright will be heading the study. Boyajian was the first to report on KIC 8462852's peculiar light-curve in September 2015, which was initially flagged by citizen scientists participating in the Planet Hunters project. Tabby's Star is so-named in honor of Boyajian.
The project asks for the help of the public to look at candidate exoplanet transits from NASA's Kepler Space Telescope. Kepler has confirmed hundreds of worlds orbiting other stars by detecting the dip in brightness of a star (described by the star's "light-curve") by an exoplanet passing in front - an event known as a "transit." And the transit signal produced by Tabby's star was as dramatic as it was bizarre.
Typically, an exoplanet signal might dim a star's light by around 2%. But several of the irregular transits of Tabby's Star caused the starlight to drop by up to 22%. This means that something very big must be passing in front. What's more, it seems the star's brightness has been dimming for hundreds of years according to historical astronomical records, only adding to the intrigue. Although several ideas have been put forward to explain the signal, the key one being the possibility of a huge cloud of comets drifting in front of the star, all have fallen short of fully explaining the Kepler observation.
After the weirdness of Tabby's Star was known, Jason Wright discussed the possibility of Tabby's Star's dimming not being caused by natural phenomena; could the dimming be caused by an advanced alien intelligence creating a "megastructure" around the star? Could this be the first observational evidence of a huge solar array (like a Dyson Sphere) being built?
For now, this is pure speculation, but Breakthrough Listen hopes to investigate further. If this hypothetical alien civilization is transmitting powerful radio signals into space, perhaps we'll detect it. Though it is highly unlikely an artificial radio signal will be detected, the mere chance Tabby's Star might spill its secrets in the form of transmissions from an advanced alien race is enough for us to at least try.