These days, when Stephen Hawking speaks, there’s basically a 50 percent chance he’ll be discussing his ideas on the apocalyptic doom of humanity on this planet. The latest call to get off Earth came with a specific destination, though.

In his latest plea for humans to escape this rock as soon as possible, the famed theoretical physicist told Starmus Festival attendees Tuesday that humans need to prepare an exodus out to other worlds within the next 200 to 500 years.

“We are running out of space, and the only place we can go to are other worlds,” Hawking said to audience gathered around his video livestream the science and music festival in Trondheim, Norway. “It is time to explore other solar systems. Spreading out may be the only thing that saves us from ourselves. I am convinced that humans need to leave Earth.”

What does Hawking propose? It’s simple: he wants the world to build an international moon colony within 30 years, with a Mars base to follow a few decades after.

This imagining of a moon outpost commissioned was by the European Space Agency.

That’s not a very farfetched idea. The European Space Agency already wants to build a moon base by 2040, and China may be a critical partner in that project.

Meanwhile, when it comes to the red planet, SpaceX is gunning for sometime shortly after 2025, while NASA thinks it can do the same by the mid-2030s. Both parties would like to see a permanent presence established on Mars, with SpaceX particularly working to build a transportation system which can help create a sustainable flow of people and resources to Mars.

BENNU’S JOURNEY - Early Earth
This is an artist's concept of the young Earth being bombarded by asteroids. 

“Earth is under threat from so many areas that it is difficult for me to be positive,” said Hawking. He suggested that existential threats like a cataclysmic asteroid impact were “guaranteed by the laws of physics and probability,” assuming human-induced catastrophes like global warming or nuclear war didn’t already annihilate the species. “I am arguing for the future of humanity and a long-term strategy to achieve this.”

The leap to places like the moon or Mars are simply the beginning, in Hawking’s view. He would like to see humans expand to possibly habitable worlds like Proxima b or the TRAPPIST-1 system, but unfortunately humans have yet to master the technology that would allow for interstellar travel. Proxima b is still over four light-years, while TRAPPIST-1 is a whopping 40 light-years away. And these are the nearby worlds.

Hawking, despite his cynicism about humanity’s future, also believes the species has a great potential to thrive if it can get off of Earth. “The human race has existed as a separate species for about 2 million years,” he said. “Civilization began about 10,000 years ago, and the rate of development has been steadily increasing. If humanity is to continue for another million years, our future lies in boldly going where no one else has gone before.”

Photos via ESA/ Foster + Partners, Flickr / NASA Goddard Photo and Video, Getty Images / Bryan Bedder