The video ranks the wildest alien megastructure ideas, from famous Dyson spheres to black-hole planets, ring worlds, ...

There's a prosaic explanation for at least some of the weirdness of "Tabby's star," it would appear. The bizarre long-term dimming of Tabby's star — also known as Boyajian's star, or, more formally, ...

Alien civilizations may have left traces. We just may not have been looking in the right place.