The rotation curves of galaxies show that the orbital velocities of stars in galaxies do not decrease as far as expected based on the visible matter in the galaxies. This suggests that there is additional mass, or dark matter, present in galaxies that is not visible to telescopes.

Dark matter is estimated to make up around 27% of the universe, with ordinary matter making up only about 5%.

The nature of dark matter is still unknown, but there are several theories about what it might be made of. Some of the leading candidates include weakly interacting massive particles (WIMPs), axions, and primordial black holes.

Dark matter plays a crucial role in the formation and evolution of galaxies. It helps to hold galaxies together, provides the fuel for star formation, and regulates the growth of supermassive black holes.

Studying dark matter is challenging because it is invisible to telescopes, interacts very weakly with ordinary matter, and is difficult to distinguish from other forms of matter.

There are several methods used to study dark matter, including observing the rotation curves of galaxies, gravitational lensing, and weak lensing.

The potential consequences of dark matter for the future of the universe are still being debated, but they could include causing the universe to expand forever, causing the universe to collapse in on itself, or leading to the formation of new types of galaxies.

Dark matter is thought to be the fuel for the growth of supermassive black holes. As dark matter falls into the center of a galaxy, it can form a dense core that attracts more dark matter and gas. This can eventually lead to the formation of a supermassive black hole.

Dark matter plays a crucial role in the formation of galaxies. It provides the initial density perturbations that lead to the formation of galaxies, helps to hold galaxies together, and regulates the growth of stars and galaxies.

There is a variety of evidence for the existence of dark matter in galaxy clusters, including the gravitational lensing of light, the X-ray emission from galaxy clusters, and the Sunyaev-Zel'dovich effect.

Dark matter affects the polarization, temperature, and shape of the cosmic microwave background.

Dark matter plays a crucial role in the formation of stars. It provides the initial density perturbations that lead to the formation of stars, helps to collapse gas clouds into stars, and regulates the growth of stars.

There is a variety of evidence for the existence of dark matter in dwarf galaxies, including the rotation curves of dwarf galaxies, the gravitational lensing of light, and the X-ray emission from dwarf galaxies.

Dark matter played a crucial role in the formation of the Milky Way. It was the dominant component of the Milky Way in its early stages, helped to shape the Milky Way's spiral structure, and regulates the growth of the Milky Way's supermassive black hole.

The future of dark matter research is bright. New experiments are being developed to directly detect dark matter, cosmological observations are being used to constrain the properties of dark matter, and theoretical models are being developed to explain the nature of dark matter.