It is hypersphere. It is the 4th dimension's surface that is perfectly
round. The curved universe is the hypersurface of the 4 dimensional
hypersphere. The hypersphere is expanding and the universe is growing
away from the 4 dimensional center. There is no outside. There is only
one universe with a beginning to time of which there was no before.
The future is infinite. The future of the hypersphere is Infinity.

Mitch Raemsch