Top physicist Professor Stephen Hawking has repeated his warning that human survival depends on finding a new home beyond the Earth.
The search for other planets to colonise should start now, he believes.
"I strongly believe we should start seeking alternative planets for possible habitation," the professor said in London at a press conference previewing the Starmus science and arts festival taking place in Norway next month.
"We are running out of space on Earth and we need to break through the technical limitations preventing us living elsewhere in the universe."
Prof Hawking was presented with a special gold watch from Omega, new sponsors of the Stephen Hawking medal for science communication.
Three of the medals, which recognise achievements in making science more accessible, will be presented at the Starmus festival in Trondheim.
Each winner will also receive one of the 18-carat gold watches. Prof Hawking will be a keynote speaker at the festival.
"Its fun and it's science and it's music," Starmus founder and astrophysicist Dr Garik Israelian said.
"This festival is about artists and scientists. The two most important values we have on this planet are science and art."