Unless humans colonise space within the next two centuries, they will become extinct, noted astrophysicist Stephen Hawking has warned adding: "Our only chance of long term survival is not to remain on planet earth."
Hawking said he was an optimist but the next few hundred years had to be tackled carefully if the human race has to survive, Daily Mail reported Monday quoting an interview with website Big Think.
Stephen Hawking said: "I see great danger for the human race. There have been a number of times in the past when survival has been a question of touch and go.
"But I am an optimist. If we can avoid disaster for the next two centuries our species should be safe as we spread into space."
Hawking said that "if we are the only intelligent beings in the galaxy we should make sure we survive and continue."
"Our genetic code carries selfish and aggressive instincts that were a survival advantage in the past. It will be difficult enough to avoid disaster in the next 100 years let alone the next thousand or a million."
He observed: "Our only chance of long term survival is not to remain on planet earth but to spread into space. We have made remarkable progress in the last 100 years but if we want to continue beyond the next 100 years our future is in space."
He made it clear that he favoured manned space flight.