When you look around the Universe you live in, it looks like a 3D space, just like the surface of the Earth looks like a 2D space. However, just like the Earth, if you were to look at the Universe as a whole, it could be a more complicated space.
Years of observational data, cosmological models and physics suggest the Universe is flat. However, a recent study suggests that the Universe is actually curved and closed, like an inflating sphere.
