joseph wrote:
nDervish wrote:
I seem to recall having read a mention at some point that Hyperborea is concave, although that didn't specify whether it was referring to the upper or lower surface.
I don't have the book in front of me, but I am sure the reference is in the Gazatteer... Hyperborea is slightly convex (like a bowl upside-down) so that the seas move outwards and don't swamp the land. Sorry I don't have the page...
Not sure why I didn't think to look there... It's p.179, first sentence of the "HYPERBOREA in RELATION to OLD EARTH and the CELESTIAL BODIES" section:
Hyperborea is a flat, hexagonal plane, though men of learning who measure the stars suggest the realm to be somewhat concave.
So I did remember correctly - it says concave, not convex. (According to a text search, the word "convex" does not appear in the GM's book and this is the only occurrence of "concave".)
I would expect that the reason the seas flow off the edge rather than draining into the center would be due to the Hyperboran hexagon spinning around an axis that runs through Mt.V., causing centrifugal force[1] to pull the seas outward. (If it doesn't spin, then that would mean that Helios orbits Hyperborea. Which is possible, given that Hyperborea already discards large chunks of real-world science anyhow. Has that ever been addressed in canon?)
In any case, whether Hyperborea is completely flat or slightly concave, that would mean that there's no horizon as we know it and suggest that Mt.V. should be visible from anywhere, unless another object is in the way or you're far enough away that atmospheric attenuation renders it too dim to be perceived (although I'm not sure whether Hyperborea is large enough for that to happen).
[1] Yes, I know there's no such thing as "centrifugal force" in the real world, it's actually just the action of inertia within a non-inertial frame of reference. But it's also the most straightforward way to express myself here.