 We're the part of the lost world that they don't know about, and they could discover us just like we discovered some distant island or country. And that, again, is probably in the 15, 1600s that that idea starts to occur to people that there might be actual involvement between aliens and life and in human life. But it's not until a bit later that that starts to become a somewhat credible theory in the 20th century when we add in a space flight, frankly.