I think we should add a NPC called Galileo in Artis library or something similar.
Just like Galileu Galilei, whom this NPC is based on, he have contacts (eg. whoever is the leader of the legion), and people say he is crazy. But there's a major difference.
In real world, earth moves on itself and around the Sun. But we know the mana world is flat, and that either the sun spins around the planet in an uneven way (because day last longer than night) or that the sun is static (in case you guys doesn't wants to add a day/night cycle, or in case you plan having a "light world" and a "dark world"). (This info is co-sourced from IRC logs).
Therefore, Galileo would explain how day/night cycle, seasons, etc. works ingame (and explain the issue with ship travels).
Bonus points if he is mocked/deemed crazy by some other random generic NPC.