Yeah, I’ve been watching in a little X-Files binge-watching (man, Gillian Anderson was hot), but I would be interested in this story anyway. It is a mystery, but a serious mystery reported by serious science journals.
A star, named KIC 8462852, has been found with a highly curious transit signal. In a paper submitted to the journal Monthly Notices of the Royal Astronomical Society, astronomers, including citizen scientists from the Planet Hunters crowdsourcing program, report: “Over the duration of the Kepler mission, KIC 8462852 was observed to undergo irregularly shaped, aperiodic dips in flux down to below the 20 percent level.”
The research paper is thorough, describing the phenomenon, pointing out that this star is unique – we’ve seen nothing like it. Kepler has collected data on this star steadily for four years. It’s not instrumental error. Kepler isn’t seeing things; the signal is real.
“We’d never seen anything like this star,” Tabetha Boyajian, a postdoctorate researcher at Yale University and lead author, told The Atlantic. “It was really weird. We thought it might be bad data or movement on the spacecraft, but everything checked out.”
The Planet Hunters volunteers are depended on to seek out transits in Kepler’s stars in the direction of the constellation Cygnus. This is a huge quantity of data, from over 150,000 stars in Kepler’s original field of view, and you can’t beat the human eye when identifying a true dip in starlight brightness. The Planet Hunters described KIC 8462852 as “bizarre,” “interesting” and a “giant transit.” They’re not wrong.
Follow-up studies focus on two interesting transit events at KIC 8462852, one that was detected between days 788 and 795 of the Kepler mission and between days 1510 to 1570. The researchers have tagged these events as D800 and D1500 respectively.
The D800 event appears to have been a single transit causing a star brightness drop-off of 15 percent, whereas D1500 was a burst of several transits, possibly indicating a clump of different objects, forcing a brightness dip of up to 22 percent. To cause such dips in brightness, these transiting objects must be huge.
Okay. So the brightness of a distant star drops off in two events.
So what causes the brightness of a distant star to drop off? That’s a no-brainer. Something crosses in front of it. Like, say, a large planet.
The problem is that planets orbit a star with periodic rotations (we go around the sun once every 365 days). Whatever transited in front of KIC 8462852, a mature F-type star (approximately 1.5 times the size of our sun), was not periodic.
Maybe it was a big cloud of space dust… thicker in some areas and not so think in other areas… passing in front not twice, but just once? Nope. They checked for that.
The researchers also investigated the possibility of a huge planetary collision: could the debris from this smashup be creating this strange signal? The likelihood of us seeing a planetary collision is extremely low. There is no evidence in data taken by NASA’s Wide-field Infrared Survey Explorer (WISE) that a collision happened, creating a very tiny window of opportunity between WISE’s mission end and the beginning of Kepler’s mission (of a few years) for an astronomically unlikely cosmic event like this to occur.
The only natural explanation favored by the researchers seems to focus on an intervening clump of exocomets.
“One way we imagine such a barrage of comets could be triggered is by the passage of a field star through the system,” write the researchers.
Indeed, they argue, there’s a nearby star that might have tidally disturbed otherwise dormant comets in the outermost regions of the KIC 8462852 star system. This small star is located around 1,000 AU from KIC 8462852 and whether it’s a binary partner or an interstellar visitor, its presence may have caused some cometary turmoil. Like the other scenarios, however, the exocomet explanation still falls short of being fully satisfactory.
So once you have ruled natural phenomena, what do you have left? Artificial phenomena. In other words: a mega-engineering project created by an advanced alien civilization.
Indeed, hunting down huge structures that obscure the light from stars is no new thing. The Search for Extraterrestrial Technology (SETT) is one such project that does just this. Only recently, a survey of the local universe focused on the hope of detecting the waste heat generated by a technologically advanced civilization, specifically a Type II Kardashev civilization.
On the Kardashev scale, a Type II civilization has the ability to utilize all the available energy radiating from a star. Using a vast shell or series of rings surrounding a star, a Dyson sphere-like structure may be constructed. This has the effect of blotting out the star from view in visible wavelengths, but once the solar energy has been used by the alien civilization, the energy is shifted to longer wavelengths and likely lost as infrared radiation.
Basically. what it could be is a “swarm of megastructures,” possibly created to capture energy from the star. Like giant solar collectors the size of many large planets. Cool.
The next step is to point a radio antenna at KIC 8462852, just to see whether the system is generating any artificial radio signals that could indicate the presence of something we’d define as “intelligent.” Boyajian and Wright have now teamed up with Andrew Siemion, the Director of the SETI Research Center at the University of California, Berkeley, to get a radio telescope to listen into the star and if they detect an artificial signal, they will request time on the Very Large Array (VLA) to deduce whether any radio signals from that star are the chatter of an alien civilization.
It might be a long shot, and the phenomenon is more likely a clump of comets or some other natural phenomenon that we haven’t accounted for blocking star light from view, but it’s worth investigating, especially if there really is some kind of alien intelligence building structures, or perhaps, ancient structures of a civilization long-gone, around a star only 1,500 light-years away from Earth.