Prof. Stephen Hawking. David Parry/Press Association/AP Photo

Stephen Hawking, the famed astrophysicist, says we need to spread into outer space or else. If we don’t, he says, it will be difficult for the world “to avoid disaster in the next hundred years, let alone the next thousand or million.”

Hawking who has Lou Gehrig’s disease and speaks with the aid of a computer-synthesized voice, gave an interview to the Canadian Press to promote a new television series in the U.K. and Canada, “ Brave New World With Stephen Hawking.” He answered questions by email, calling space exploration our most urgent mission.

“We are entering an increasingly dangerous period of our history,” he wrote in excerpts published by the Winnipeg Free Press and cited widely elsewhere.

“Our population and our use of the finite resources of planet Earth are growing exponentially, along with our technical ability to change the environment for good or ill. But our genetic code still carries the selfish and aggressive instincts that were of survival advantage in the past. It will be difficult enough to avoid disaster in the next hundred years, let alone the next thousand or million.

“Our only chance of long-term survival is not to remain lurking on planet Earth, but to spread out into space.”

Hawking, now 69, has spoken on this theme before, though he warned in 2010 that it may be “too risky” to seek out intelligent aliens that he said almost certainly exist.

“If aliens visit us, the outcome would be much as when Columbus landed in America, which didn’t turn out well for the Native Americans,” he said at the time. “We only have to look at ourselves to see how intelligent life might develop into something we wouldn’t want to meet.”