The Fermi paradox states that, since there are nearly endless chances for life to evolve in the universe, civilizations must occur in some of those instances. But to date there have been no signs of these civilizations. Bill Nye has a simple yet hopeful answer to the mystery.
Technically, if you look at ancient hieroglyphs, as well as crop circles, aliens HAVE been communicating with us. Not only that, but they’ve been visiting and interacting with the Earth since the time it became a habitable planet.
I’m not sure I would buy into crop circles but ancient history is certainly worth exploring. 🙂