Seeds of Galaxies

Inflation didn't just smooth things out. Quantum fluctuations, normally confined to subatomic scales, were stretched to cosmic proportions. These became tiny density variations in the early universe, and regions slightly denser than average pulled in more matter through gravity over billions of years.

Those seeds grew into the large-scale structure we see today: galaxy clusters, filaments, and voids. The pattern of hot and cold spots in the cosmic microwave background matches inflation's predictions with striking accuracy.