An Etymological Dictionary of Astronomy and Astrophysics

A → cosmological model that attributes the formation of structures in the → early Universe to an exotic particle (→ cold dark matter) which was → non-relativistic at the time of → decoupling.
According to this model, CDM began clumping together soon
after the → Big Bang, while the → baryonic matter was still coupled with the → photons, and prevented to condense. Smaller → clumps of dark matter merged to form larger and larger clumps, and when the normal visible matter had decoupled from the photons, at the → recombination era (380,000 years after the Big Bang), it collapsed onto these dark matter clumps. In this way, the dark matter clumps acted as seeds for galaxy formation.

See also: → cold; → dark; → matter; → theory.