"Proserpine, a planet much larger than our Earth at a distance of almost ten billion kilometers from the Sun, with a revolution period of 512 terrestrial years. Nobody on Earth can say for sure that he has seen Proserpine and I doubt very much that it will ever be visible from a terrestrial vantage point. Yet our ancestors had knowledge of its existence. Some people might be surprised about my assurance that our ancestors knew the planets Uranus and Neptune as well as the precession of the equinoxes. This assurance is shared today by many authors trying to explain our ancestors' astonishing knowledge of astronomy."
-Maurice Chatelain, a designer of the Apollo space craft, and NASA Chief of Communications for the Apollo lunar missions