Stephen Hawking, theoretical physicist and cosmologist, has come forward this week with a warning for humanity. Our attempts to contact extra-terrestrial beings by broadcasting messages into space may be unwise, he thinks, as said aliens may turn out to be hostile.

He has warned against contacting aliens in a new film, Stephen Hawking’s Favourite Places. He said that broadcasting our presence to any alien civilisations, advanced in technology than humans, could be dangerous.

In a new online film, he compared the first contact of advanced aliens with the situation when native Americans first encountered Christopher Columbus and things “didn’t turn out so well”.

The film takes viewers to five significant locations across the cosmos, on his spacecraft — the SS Hawking, in which the British scientist performs a hypothetical flyby of Gliese 832c, a potentially habitable exoplanet located 16 light years away.

“One day we might receive a signal from a planet like Gliese 832c, but we should be wary of answering back,” he said. “They will be vastly more powerful and may not see us as any more valuable than we see bacteria.”

Hawking seems to be serious about the matter, as he has also warned earlier about the prospect of hostile aliens. During the launch of the Breakthrough Listen project, he suggested that any civilisation reading our messages could be billions of years ahead of humans.

The project was launched last year, which scans the nearest million stars for signs of life. “The Breakthrough Listen project will scan the nearest million stars for signs of life, but I know just the place to start looking,” he said, in the film that appeared on the online platform CuriosityStream.

Even “if aliens visit us, the outcome could be much like when Columbus landed in America, which didn’t turn out well for the Native Americans,” Professor Hawking said.

“Such advanced aliens would perhaps become nomads, looking to conquer and colonize whatever planets they can reach,” he added.