Time travel used to be thought of as just science fiction, but Einstein's general theory of relativity allows for the possibility that we could warp space-time so much that you could go off in a rocket and return before you set out.
“Really, we don't know what to make of it except that we're delighted about it. We have all these fans thirty years later and they're still around and will probably be around for a long time to come.”
“The process is very gradual, you see. At first there's the tainted stage; they know what will eventually happen to them if they go on but they say, 'Oh God, don't do it to me do it again, please, please.'”