Riemann tensor

The Riemann curvature tensor is a mathematical tool used in Einstein's theory of general relativity to describe how spacetime is curved by mass and energy. Imagine spacetime as a flexible fabric: the Riemann tensor measures how much and in what way this fabric twists or bends when influenced by objects like stars or planets. It captures the intrinsic curvature, affecting how objects move and how light travels, revealing the geometric properties of the universe that underlie gravity. In essence, it helps quantify the shape and structure of the universe at a fundamental level.