Cold dark matter is the primary component of dark matter halos. It is a type of non-baryonic matter that does not interact with electromagnetic radiation and is thought to be composed of weakly interacting massive particles (WIMPs).

Dark matter halos can form through a variety of mechanisms, including the collapse of primordial gas clouds, the merging of smaller halos, and the accretion of dark matter onto galaxies.

The typical mass of a dark matter halo is around 10^12 Msun. However, the mass of dark matter halos can vary significantly, ranging from dwarf halos with masses of 10^8 Msun to galaxy cluster halos with masses of 10^15 Msun.

The density profile of a dark matter halo is typically described by the Navarro-Frenk-White (NFW) profile. The NFW profile is a cuspy profile, meaning that the density of the halo increases towards the center.

Dark matter plays a crucial role in galaxy formation. It provides the gravitational potential that holds galaxies together, helps to regulate the star formation rate in galaxies, and shapes the morphology of galaxies.

There is a wealth of evidence for the existence of dark matter, including the rotation curves of galaxies, the gravitational lensing of light, and the cosmic microwave background.

There are a number of challenges in studying dark matter, including the difficulty of detecting dark matter directly, our lack of knowledge about the properties of dark matter, and the fact that dark matter is not well-understood theoretically.

There are a number of proposed solutions to the dark matter problem, including modified Newtonian dynamics (MOND), axion dark matter, and sterile neutrino dark matter.

The future of dark matter research lies in a combination of direct detection experiments, indirect detection experiments, and theoretical studies.

Dark matter is the dominant form of matter in the universe, plays a crucial role in galaxy formation and evolution, and affects the expansion of the universe.

Dark matter causes light to bend due to its gravitational pull. This effect is known as gravitational lensing.

The cosmic microwave background is the leftover radiation from the Big Bang. It is a faint glow of light that fills the entire universe.

Dark matter causes the rotation curves of galaxies to flatten. This is because the gravitational pull of dark matter extends beyond the visible matter in galaxies.

Dark matter plays a crucial role in the formation of galaxies. It provides the gravitational potential that allows galaxies to form, helps to regulate the star formation rate in galaxies, and shapes the morphology of galaxies.

The future of dark matter research lies in a combination of direct detection experiments, indirect detection experiments, and theoretical studies.