On 4/23/2013 3:23 PM, RichD wrote: > Supposedly, our universe is closed and finite, although the > geometry and topology isn't precisely known. This means > a straight line (geodesic) traveler must return to his starting > poiint, yes/no? Hence, curved space.
no - a flat torus... is flat, closed and finite, and a traveler returns to his starting point. Same for Poincaré dodecahedron for instance etc.