Colonize other Planets?

"Humans must colonize other planets."
A recent quote from Stephen Hawking-a British cosmologist.

"Sooner or later disasters such as an asteroid collision or a nuclear war could wipe us all out," said Professor Hawking, who was crippled by a muscle disease at the age of 21 and who speaks through a computerized voice synthesizer.

"But once we spread out into space and establish independent colonies, our future should be safe," said Hawking, who was due to receive the world's oldest award for scientific achievement, the Copley medal, from Britain's Royal Society on Thursday."-Read more atReuters