The Huffington Post: Theoretical physicist Stephen Hawking, in an interview with Big Think, warns that if humans can't find another planet to inhabit, they will face extinction. 'We are entering an increasingly dangerous period in our history,' Hawking says. 'There have been a number of times in the past when survival has been a question of touch and go,' ... and the frequency of such occasions 'is likely to increase in the future.'... Because we are rapidly depleting the finite natural resources that Earth provides, and because our genetic code 'carries selfish and aggressive instincts,' our 'only chance for longterm survival' may be to 'spread out into space.'