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

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.