Cold Dark Matter

Cold Dark Matter (CDM) refers to a type of matter that makes up a significant portion of the universe, but does not emit, absorb, or reflect light, making it invisible and detectable only through its gravitational effects. "Cold" means it moves slowly compared to the speed of light and clusters together, forming the framework for galaxies and larger cosmic structures. CDM helps explain how galaxies formed and evolved in the universe, providing a crucial component to our understanding of cosmology and the large-scale structure of the cosmos. It differs from "hot" dark matter, which moves quickly and is less effective at clumping together.