hierarchical structure formation

Hierarchical structure formation is the process by which small cosmic structures, like tiny gas clouds, gradually merge over time to form larger objects such as galaxies, galaxy clusters, and superclusters. Initially, slight density fluctuations in the early universe caused matter to clump together under gravity. These small clumps combined to build bigger structures in stages, much like building with increasingly larger blocks. This step-by-step merging explains the vast and complex cosmic web we see today, where vast galaxies and clusters are interconnected by filaments of dark matter and gas.