Does The Universe Have A Shape?
Scientists have proposed many models to sum up the shape of the universe, though it's difficult to represent something that's both infinitely vast and (at least) four-dimensional. The three types of universe shapes that are commonly discussed are positively curved, negatively curved, and flat. As of 2015, evidence points to a flat universe over the other two models.
from Universe Today
Key Facts In This Video
There are three main proposed models for the shape of the universe: positively curved, negatively curved, and flat. (1:22)
A negatively curved universe would look like a four-dimensional saddle, and would contain too little energy to ever stop expanding. (2:56)
One negatively curved model of the universe resembles a trumpet. (4:26)