Riemann–Christoffel tensor

The Riemann-Christoffel tensor is like a very special calculator that helps scientists understand how things move in space. It tells scientists about the "curvature" of space, which is like how much it bends in different directions. For example, if you look at a basketball in 3D it looks like a round ball, but if you look at it from the side it looks like an oval, this is because its surface curves in different ways. The Riemann-Christoffel tensor helps scientists understand how much it curves in different directions and how all the pieces of the ball fit together.