Stephen Hawking Is Still Afraid of Aliens

Humanity should be wary of seeking out contact with alien civilizations, Stephen Hawking has warned once again. In 2010, the famed astrophysicist said that intelligent aliens may be rapacious marauders, roaming the cosmos in search of resources to plunder and planets to conquer and colonize. "One day, we might receive a signal from a planet like this," Hawking says in the documentary, referring to a potentially habitable alien world known as Gliese 832c.