I have a great deal of respect for Hawking, but... Lately it seems like he has said a couple of crazy things. We (as in most humans) are NOT going to get off the earth. Earth will always be the best chance for a planet for humans. Let's take care of it. And AI is NOT anywhere near becoming really intelligent. Anyone who has interacted with Siri knows that she has no real understanding. And the Google car and other autonomous driving systems are already safer and probably better for traffic than almost all drivers, but they still, and will most likely for a long time, need a human driver to take over under circumstances that actually require thought. AI is advancing, but it has always advanced slower than predicted. A lot slower than predicted. And while there are signs that AI will continue to be more and more useful as time goes on, and in some circumstances like recognizing driving, captchas and playing chess and jeopardy it will outperform humans in simple tests, it is not anywhere near, nor will it be for a long time, outperform the human brain in a general way. And certainly it is NOT similar to an alien (as in from outer space, not from another country on earth) civilization.