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Allen Telescope Array
The antennas of the Allen Telescope Array in California is collecting signals from a strange star known as KIC 8462852. (Credit: SETI Institute)

One of the premier telescope arrays in the search for extraterrestrial intelligence, or SETI, is focusing its antennas on an anomalously blinking star, thanks in part to speculation that the star called KIC 8462852 could harbor a network of alien megastructures.

The Allen Telescope Array, a complex of 42 radio dishes in Northern California that was funded in part by Seattle billionaire Paul Allen, has been collecting data about the star since Thursday evening, SETI Institute researcher Doug Vakoch told GeekWire.

Thursday is just about the time that speculation about the star reached fever pitch on the Internet – and the observation campaign (as well as the fever pitch) is expected to continue for at least a few more days. KIC 8462852, which is about 1,500 light-years from Earth in the constellation Cygnus, has become what some have called the “most mysterious star in our galaxy” on the basis of data from NASA’s Kepler planet-hunting probe.

What makes the star mysterious is the fact that it appears to get drastically dimmer on an erratic time schedule, at intervals ranging from five to 80 days. The anomalous behavior was documented as part of Kepler’s mission to look for potential planets around more than 100,000 stars in a small patch of sky – but KIC 8462852’s weirdness lay hidden in the Kepler database until it was brought to light by a citizen-science project known as Planet Hunters.

Yale astronomer Tabetha Boyajian, who oversees Planet Hunters, is the principal author of a research paper in which she and her colleagues run through the scenarios that could cause the anomalies. They say the best natural explanation is that gravitational interaction with a passing star only recently stirred up irregular streams of comets that are periodically blocking the starlight from KIC 8462852. That would be a bizarre coincidence, but it would fit the data.

This chart shows the light curve for KIC 8462852, observed by NASA's Kepler space telescope. The light levels dipped erratically by as much as 21 percent, sparking a mystery. (Credit: T. Boyajian via J. Wright)
This chart shows the light curve for KIC 8462852, observed by NASA’s Kepler space telescope. The light levels dipped erratically by as much as 22 percent, sparking a mystery. (Credit: T. Boyajian via J. Wright)

Penn State astronomer Jason Wright is advancing an even more bizarre explanation: He suggests that extraterrestrial spacefarers might have built a collection of large structures in orbit around KIC 8462852 – perhaps to convert stellar radiation into industrial power. Such systems, known as Dyson spheres, have been talked about for decades as potential energy sources for advanced civilizations.

“Aliens should always be the very last hypothesis you consider, but this looked like something you would expect an alien civilization to build,” Wright told The Atlantic. Last week, Wright and his colleagues laid out the scenario in their own research paper, which has been submitted to the Astrophysical Journal.

Many researchers, including Vakoch, say it’s highly unlikely that the alien scenario will pan out. The cause is more likely to be the comet scenario or some other natural phenomenon, perhaps even a phenomenon that hadn’t been considered before. Such was the case back in the 1970s, when a strangely oscillating star that was at first called LGM-1 (for “Little Green Men”) turned out to be the first observed radio pulsar.

Despite the doubts, Vakoch said “we have an obligation to do as rapid a follow-up as we can.” He said the Allen Telescope Array is analyzing KIC 8462852’s radio signals in 9 billion channels, over wavelengths ranging from 1 to 10 GHz.

“We hop along one hertz at a time … focusing on a search for narrowband signals,” Vakoch explained. Such signals could be considered a reliable indicator of intentional broadcasts.

Vakoch said the SETI Institute’s search doesn’t eliminate the need for further observations by other radio instruments, such as the Green Bank Telescope in West Virginia or the Very Large Array in New Mexico. Boyajian, Wright and their colleagues are making their pitch to have those big radio dishes focus on KIC 8462852 in the months ahead.

“I think the biggest success of this discovery is citizen science,” Vakoch said. “Whatever the ultimate explanation for this phenomenon is, it’s something we would never have seen without the marriage of humans and computer technology.”

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