Friedman-Lemaître-Robertson-Walker metric

The Friedmann-Lemaître-Robertson-Walker (FLRW) metric is a mathematical model used in cosmology to describe the large-scale structure of the universe. It assumes that the universe is homogeneous and isotropic—that is, looks the same everywhere and in all directions—allowing scientists to understand how the universe expands or contracts over time. This metric provides the foundation for the Big Bang theory, helping us predict how distances between galaxies change and how the universe's shape and size evolve, based on parameters like matter density, dark energy, and curvature.