Leon Csernohlavek

Physicist Stephen Hawking has reasserted his view that humans must become an interstellar species in the near future or risk “being annihilated”.

“The Earth is under threat from so many areas that it is difficult for me to be positive,” the professor said in a speech given via video link to the Starmus science conference in Trondheim, Norway.


Hawking has previously predicted that climate change, epidemics and population growth all pose major threats to our survival on Earth. In November of last year he said humans would need to find a new planet within the next thousand years. In May, he shortened that prediction to 100 years.

“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,” Hawking said. “To stay, risks being annihilated.”

He called on a global effort to “rekindle the excitement” of space travel in the 1960s, arguing the technology needed to make the next leap is “almost within our grasp”. He predicted the construction of a base on the Moon within the next 30 years and said humans are likely to reach Mars within the next 50 years. Ambitious goals of a base on the Moon by 2020 and a manned landing on Mars by 2025, he continued, would “re-ignite the space programme and give it a sense of purpose” not seen in decades.


“Spreading out into space will completely change the future of humanity. It may also determine whether we have any future at all.” Beyond Earth and Mars, Hawking name-checked the Breakthrough Star Shot programme he’s working on alongside Yuri Milner. If successful, he said the mission could send a probe to Alpha Centauri, the nearest star to the Sun, within the lifetime of people alive today. The project would see a tiny, fully functional probe attached to a vast, lightweight light sail that is propelled at a fifth the speed of light using an Earth-based laser array that hits the sail with tens of gigawatts of power.

“Such a system could reach Mars in less than an hour, reach Pluto in days, pass Voyager is under a week, and reach Alpha Centauri in just over 20 years,” Hawking said. That same laser array would then be used to receive the signal from the probe, which would hopefully contain the first close-up images of Proxima b, an Earth-sized planet that’s in the habitable zone around Alpha Centauri.

While major engineering challenges remain if the mission is to be realised, Hawking remains committed to it. “These are engineering problems, and engineers’ challenges tend, eventually, to be solved,” he said.