What is a Sphere? Definition and Examples

A sphere is curved, not flat. Our perception that it is flat is influenced by the fact that we cannot see the Earth from a great distance. Satellite imagery captured by satellites have confirmed that the Earth is indeed curved or round.

The Earth is called a sphere because it resembles very much a sphere. However, strictly speaking the Earth is not a perfect sphere.

In fact, real-world objects such as the Earth, a soccer ball, a marble will never be perfect spheres because they will have irregularities and imperfections here and there.

Basically, a sphere is the same as a perfect sphere. However, it is not easy to find objects in real-life that can be called perfect spheres. The term "sphere" has therefore expanded to define not only a perfect sphere, but also anything looking like a sphere. The term "perfect sphere" is just a mathematical concept.