A sphere is a perfectly round solid figure. All points on the surface of the shape are the same distance away from the centre – we call this distance the radius. The formula for the volume and ...

A ring or sphere could, apparently, be stable if surrounded by the right sizes and gravities of other stars.

A small sphere resting atop a large sphere begins to ... Jeff Smith is a former Math teacher and a retired US Navy Lieutenant Commander. Reach him at [email protected].