Now I liked A Brief History of Time and of course the whole wheelchair / voice enhancement stuff is touching, but I'm getting sick of Stephen Hawking. If he wants to shoot his mouth off to the press about event horizons, fair enough; he's got me there. But a few months ago he was talking about science vs. religion and his remarks were just D-U-M dumb, and he does it again in this story concerning colonization (which my wife brought to my attention).
OK, first some geek quibbles: In Star Trek the warp drive doesn't take you somewhere "instantly." And although it relies on matter/antimatter annihilations, it also allows faster-than-light travel. So what Hawking is talking about in this article would be a far cry from "Star Trek propulsion."
Another quibble: A nuclear war couldn't "wipe us all out." It would destroy modern civilization, perhaps, but it wouldn't exterminate the human race. I suspect his remarks here are less based on scientific inquiry and more on the views of "sophisticated" crowds in which he travels.
Major objection (1): Why would we need to go to other star systems to be safe? Wouldn't it be enough to establish space stations or colonies on asteroids / the moon / Mars?
Major objection (2): You'd have to go a lot farther than the next star system if the goal is to find an inhabitable planet. In fact, I've read some compelling investigations that conclude Earth may possibly be the only planet in the universe hospitable for human life. (You scoff and say, "C'mon there are trillions of planets," but there are all sorts of things that could make life impossible.)
Major objection (3): Who cares how long the trip is? I think when pioneers venture out to colonize other star systems, they are probably going to be in ships that are self-sufficient, as opposed to having (say) 7 years of supplies and then hoping to replenish once they reach Alpha Centauri. So if that's true, then whether it takes 7 or 700 years to reach the destination is irrelevant.
OK in closing, in fairness to Hawking I'm just relying on this news story. Maybe his actual remarks were a lot more nuanced.