What is the shape of our universe ? The shape of the Universe didn't have to be flat; it could have been positively curved like a higher-dimensional sphere or negatively curved like a higher-dimensional horse's saddle. The reason space can be curved is that its shape is not absolute, but rather determined by a mix of factors like its mass and energy distribution, as well as its expansion rate. Nevertheless, when we measure it, we find that our Universe really is flat. Here's what we can learn fr