An Etymological Dictionary of Astronomy and Astrophysics

The study of the processes that gave rise to the apparition of matter concentrations, such as → superclusters of galaxies, → galaxy clusters, and galaxies, in a homogeneous → expanding Universe. Cosmic structures are believed to result from → density fluctuations that existed in the → early Universe before radiation and matter decoupled (→ decoupling era or → recombination era). Initial → quantum fluctuations in the → inflaton field were expanded by → inflation. Inflation amplified them up to scales that correspond to those of galaxy clusters and beyond. Generally, a model of structure formation includes three main ingredients: 1) background cosmology, 2) model for fluctuation generation, and 3) types of → dark matter.
See also:
→ bottom-up structure formation, → hierarchical structure formation, → Silk damping, → top-down structure formation.

See also: → structure; → formation.