What is the role of dark matter in the formation of galaxies?

Dark matter plays a crucial role in the formation of galaxies.

Galaxies are formed through the gravitational collapse of gas and dust. However, the observed mass of galaxies is much greater than the mass of the visible matter. This discrepancy is explained by the presence of dark matter, which is thought to make up around 85% of the total matter in the universe.

Dark matter provides the gravitational force necessary to hold galaxies together. Without it, the rotational speeds of stars in the outer regions of galaxies would be too high, causing them to fly off into space. The presence of dark matter also affects the distribution of visible matter in galaxies, as it pulls on the gas and dust, causing it to clump together and form stars.

The exact nature of dark matter is still unknown, but it is thought to be made up of particles that do not interact with light or other forms of electromagnetic radiation. This makes it difficult to detect directly, but its presence can be inferred from its gravitational effects on visible matter.

In summary, dark matter is essential for the formation and stability of galaxies. Its gravitational force holds galaxies together and affects the distribution of visible matter, leading to the formation of stars and other structures within galaxies.