Stephen Hawking has spoken out about extraterrestrials, and is almost certain they exist. Furthermore, he believes that humans should be extremely cautious about first encounters. “We only have to look at ourselves to see how intelligent life might develop into something we wouldn’t want to meet. I imagine they might exist in massive ships, having used up all the resources from their home planet. Such advanced aliens would perhaps become nomads, looking to conquer and colonise whatever planets they can reach.” If this sounds familiar, it’s because the uber-genius is paraphrasing from almost…