Breakthrough Listen to search for intelligent life around Tabby's star

The Breakthrough Listen project at the University of California, Berkeley, is using the Green Bank radio telescope to see if it can detect any signals from intelligent extraterrestrials.

The focus, according to UC Berkeley, is Tabby's star, or KIC 8462852, named after Tabetha Boyajian, the assistant professor of physics and astronomy at Louisiana State University, which has provoked speculation over the past year that it hosts a highly advanced civilization capable of building orbiting megastructures to capture the star's energy.

Breakthrough Listen, created last year with 100 million U.S. dollars in funding over 10 years from the Breakthrough Prize Foundation and its founder, internet investor Yuri Milner, has the most powerful SETI, short for Search for Extraterrestrial Intelligence, equipment on the planet, and access to the largest telescopes on the planet, noted Andrew Siemion, director of the Berkeley SETI Research Center and co-director of Breakthrough Listen.

"We can look at it with greater sensitivity and for a wider range of signal types than any other experiment in the world," Siemion was quoted as saying.

First reported in September 2015 by Boyajian, then a postdoc at Yale University, Tabby's star had been flagged by citizen scientists because of its unusual pattern of dimming. These volunteers were looking at stars as part of the internet project Planet Hunters, which allows the public to search for planets around other stars in data taken by Kepler spacecraft, a project of the U.S. Natioanl Aeronautics and Space Administration (NASA), which has been monitoring 150,000 stars for regular dimming that might indicate a planet had passed in front of it.

While most such dimming by transiting planets is brief, regular and blocks just 1 or 2 percent of the light of the star, Tabby's star dims for days at a time, by as much as 22 percent, and at irregular intervals. Boyajian speculated in her 2015 paper that the irregular dimming might be explained by a swarm of comets breaking up as it approached the star, subsequent observations show the star, about 1,500 light-years from Earth in the constellation Cygnus, is far more irregular than a comet swarm would produce. In fact, it seems to have been dimming at a steady rate for the past century.

Speculation arose that the dimming was caused by a Dyson structure: a massive orbiting array of solar collectors that physicist Freeman Dyson once proposed would be a natural thing for a civilization to build. Theoretically, such a structure could surround the star and capture nearly all the star's energy.

"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, chief scientist at Berkeley SETI. "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.'"

While Siemion and his colleagues are skeptical that the star's unique behavior is a sign of an advanced civilization, he and Boyajian and UC Berkeley visiting astronomer Jason Wright are traveling to the Green Bank Observatory in rural West Virginia to start the observations, and expect to gather around 1 petabyte of data over hundreds of millions of individual radio channels.

The observations are scheduled for eight hours per night for three nights over the next two months, starting Wednesday evening, Oct. 26. And the results of their observations will not be known for more than a month, because of the data analysis required to pick out patterns in the radio emissions.

"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," Siemion said. "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." Endit