3-dimensional sphere

A 3-dimensional sphere, known as a 3-sphere or hypersphere, is a higher-dimensional analogue of the familiar 2-dimensional sphere (like the surface of a ball). Think of it as a shape that exists in four-dimensional space, where every point is equally distant from a center, just like a regular sphere but with an extra dimension. While we can’t visualize it directly, mathematicians use it to understand complex spaces and concepts in physics, such as the shape of the universe. It is a smooth, closed, and symmetrical geometric object that generalizes the properties of ordinary spheres into an additional dimension.