3 ms·

> They are negatively curved, any object thrown away on a straight line will eventually return. Isn't that describing positive curvature (e.g. a sphere)?

• chisleu 11y ago
  The inside of a sphere. http://i.imgur.com/b2KgM6X.gifv http://i.imgur.com/b2KgM6X.gifv
  • MrJagil 11y ago
    That was really interesting, do you have a source? (The title makes it seem like a joke though)
    • mungoman2 11y ago
      Google Hollow Earth. There are many conspiracy theory sites handling it, but I think it is a quite interesting concept nontheless.
• sukilot 11y ago
  No, paraboloid also has positive curvature. Sign of curvature refers to whether all curves at a point are in the same half-space (saddles have negative curvature). OP really means something like "eccentricity <1"