If alien civilizations rise and fall, they may leave behind artifacts long after they are gone. From abandoned megastructures to quiet machines orbiting dead stars, these relics could tell stories no ...

There’s no denying the allure of alien artifacts. Science fiction is awash in the material remnants of extraterrestrial civilizations, which surface in everything from the classic books of Arthur C.

"Hearst Magazines and Yahoo may earn commission or revenue on some items through these links." For every legitimate researcher trying their best to ferret out some evidence of alien life somewhere out ...