It's probably not aliens. Seriously guys, it's very, very unlikely that it's aliens. But the weird, flickering star known as KIC 8462852 still isn't sitting right with astronomers. In fact, it just got a lot weirder. Ever since KIC 84628532 was spotted in the Kepler Space Telescope's dataset, astronomers have puzzled over what the heck could be responsible for the star's logic-defying light curve. Over four years of observational data, KIC 8462852 flickered erratically, its light output sometimes dropping by as much as 20 per cent. That's highly unusual stellar behaviour, and it can't be explained by a transiting planet.
Some astronomers proposed that KIC 8462852 might be occluded by a swarm of comets. Others suggested aliens.
Specifically, astronomer Jason Wright tossed out the idea that the star's weird distortion might be the result of a giant alien construction project — you know, like a Dyson sphere. The idea electrified the citizens of Earth and mobilised a worldwide SETI search for hard evidence of our celestial neighbours. Sadly, two independent searches, for radio signals and laser beams — both of which could indicate a technological society — didn't pan out. (And remember, we've confused inexplicable observations for aliens many, many times before.)
But according to a study just released on arXiv, the comet hypothesis is now falling flat, too, and the mystery of KIC 8462852 has deepened considerably. While Kepler only has a few years of data on the star, astronomer Bradley Schaefer of Louisiana State University decided to look at photographic plates of the sky dating back to the late 19th century. To his amazement, he learned that over the last hundred years, KIC 8462852's light output has steadily faded by about 19 per cent, something that's "completely unprecedented for any F-type main sequence star".
"This presents some trouble for the comet hypothesis," Tabetha Boyajian, a lead researcher on the team that originally discovered the star, told New Scientist. "We need more data through continuous monitoring to figure out what is going on."
Indeed, it's hard to imagine either aliens or natural celestial bodies dampening a star's light output that much over such a short period of time.
It will be a while yet before we've solved the mystery of KIC 8462852. But this is what's great about scientific discovery. Literally all possible explanations are on the table at this point — and the truth about this tantalising star could be more fascinating than we ever imagined.
Top image via NASA/JPL-Caltech