When Joab tells Justin, Angie and Corky that he will sail to the edge of the Earth when he grows up, Justin laughs at him and says that it would be impossible because the Earth is round. Angie shushes him, telling Justin that they have traveled back in time before Columbus found out that the Earth is round, and so Justin shouldn't reveal future discoveries. However, contrary to popular belief, Christopher Columbus was not the first person to discover that the Earth is spherical - Pythagoras had the idea in the sixth century BC, and Aristotle found the physical evidence for it about 200 years later.