At the end of the game we see a clear image that both Inferia and Celestia are spherical worlds.
before Seyfert's Ring was destroyed it, Seyfert's Observatory and Aifread's dock were sitting on the Orbus Barrier. from Aifread's dock you could sail on either side of the Orbus Barrier such as if you entered the dock from Inferia and went onto the barrier (or entered from Celestia and rotated 180 degrees), the Observatory would be upside down.
yet you can loop around if you go in one direction. if it was like the water barrier that surrounds Ephinea (Tales of Graces) it would make sense since it's spherical around the planet. but both Inferia and Celestia are spherical and Seyfert's Ring sits between the 2 worlds on the Orbus Barrier.
So how does sailing all around the Orbus Barrier work? how does the Van Eltia not fall off an edge of the Orbus Barrier?