Earth’s inner structure could be revealed by the speed at...

Earth’s inner structure could be revealed by the speed at which waves travel from one edge to another. (Planetary Visions Ltd./Science Photo Library)

Interesting stuff, read more in Nature: Long-awaited mathematics proof could help scan Earth’s innards.

The problem is called the boundary-rigidity conjecture. It belongs to the field of Riemannian geometry, the modern theory of curved spaces with any number of dimensions. Albert Einstein built his general theory of relativity — in which mass warps the geometry of space-time — on this branch of mathematics.