1 year ago
Last edited at 8:56PM on 8/1/2012
The universe is most likely not closed, but rather flat. That is, it's average density (including baryonic matter, dark matter, and dark energy) is exactly equal to the energy between positive and negative curvatures. We know that to a 2% measurement accuracy. But regardless of that, even a closed universe doesn't have to have an end point. Like the surface of a sphere is finite but had no boundary, do can the universe be. The bottom line is that the observable universe is finite, but has no end point or boundary.
This question remains unsettled. it could very well be a closed space. Topology admits many counterintuitive spaces, some having edges, some not, some having boundaries, some not, and some being closed rather than open. We really don't know which applies to the universe we live in.