'Alien megastructures' debunked. Why are we so quick to assume it's aliens?

January 5, 2018 --The idea that there might be gigantic alien structures orbiting a distant star just bit the dust. After citizen astronomers spotted data in 2015 revealing that KIC 8462852, a star about 1,000 light years away, was dimming and brightening in a strange way, one of many explanations proposed by astronomers involved some sort of "megastructures" orbiting the star – perhaps built by aliens to harvest stellar energy. That imaginative suggestion rocketed the star to fame. But Louisiana State University astronomer Tabetha Boyajian and colleagues collected more data on the star, nicknamed "Tabby's Star" for Dr. Boyajian, and they found that the star's strange flickering was thanks to something much more mundane: ordinary dust. We see it in many different ways, and the data that we took showed a clear signature of this being what we would see from dust," Boyajian says. This may be a disappointing outcome for those hoping for proof of an alien civilization. But Tabby's Star's rise to stardom highlights a deeply entrenched human psychological quirk: When presented with a puzzling phenomenon, our knee-jerk instinct is to ask not what created it, but who. Scientists say that as social animals, we are evolutionarily predisposed to see agency and intentionality in the world around us. And when it comes to astronomical mysteries, aliens seem to fit. "It's the duct tape of science," says Seth Shostak, senior astronomer for the SETI Institute. Because we don't know what aliens might do, they could explain anything. But why do we do that? "It's not just aliens," says Christopher French, a psychologist and founder of the Anomalistic Psychology Research Unit at Goldsmiths, University of London. "We do have a natural tendency to assume that anything odd, or, superficially at least, inexplicable, that there must be some sort of intentionality behind it, some sort of intelligence, there must be a purpose, somebody or something has done that for a particular purpose.