Celebrity physicist Stephen Hawking says humans should return to the Moon by 2020 and Mars by 2025 in order to unite humanity in the shared purpose of spreading out beyond Earth. "Spreading out into space will completely change the future of humanity," the Cambridge professor said at the Starmus Festival in Trondheim, Norway. "I hope it would unite competitive nations in a single goal, to face the common challenge for us all.” He added that reaching to the Moon, Mars and beyond would also get younger people interested in science such as astrophysics and cosmology. Hawking said leaving Earth is essential as the planet faces climate change and stresses on natural resources. "We are running out of space and the only places to go to are other worlds. 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," he said. "If humanity is to continue for another million years, our future lies in boldly going where no one else has gone before.” Hawking said making the first moves into space would “elevate humanity” because it would have to involve many countries. "Whenever we make a great new leap, such as the Moon landings, we bring people and nations together, usher in new discoveries, and new technologies," he continued. "To leave Earth demands a concerted global approach, everyone should join in. We need to rekindle the excitement of the early days of space travel in the sixties." So far, the European Space Agency has announced a plan to create a “Moon Village” after the International Space Station is decommissioned in 2024. China is also reportedly interested in sending an astronaut to the Moon. The U.S. space agency, NASA, is instead focusing on manned missions to Mars, something it hopes to do by the 2030s.