Superclusters and the Cosmic Web

Galaxy clusters themselves group into superclusters — vast chains stretching hundreds of millions of light-years. The Milky Way sits in the Laniakea Supercluster, which contains 100,000 galaxies across 520 million light-years. Laniakea is not gravitationally bound — it is slowly being pulled apart by the universe's expansion.

At the largest scale, the universe has a cosmic web structure: galaxies and clusters form along filaments and walls surrounding enormous voids — regions of nearly empty space spanning hundreds of millions of light-years.