The observed rotation curves of galaxies suggest that there is more mass present than can be accounted for by the visible matter, indicating the presence of dark matter.

Dark matter is estimated to make up approximately 27% of the total energy density of the Universe, while ordinary matter makes up only about 5%.

Weakly interacting massive particles (WIMPs) are hypothetical particles that are thought to be a possible candidate for dark matter due to their weak interactions and large mass.

Dark matter plays a crucial role in shaping the structure of the Universe at various scales, from galaxies to galaxy clusters and the large-scale cosmic web.

The Bullet Cluster is a galaxy cluster that provides strong evidence for the existence of dark matter. It shows a separation between the visible matter and dark matter during a collision, indicating that dark matter is not strongly coupled to ordinary matter.

The cosmic microwave background radiation is the remnant radiation from the early Universe, providing valuable insights into the conditions and properties of the Universe shortly after the Big Bang.

The CMB provides information about the total amount of dark matter in the Universe by measuring the curvature of the Universe and the amount of matter-energy it contains.

The dark matter halo is a region of space surrounding a galaxy where dark matter is concentrated. It extends beyond the visible matter of the galaxy and plays a crucial role in shaping its structure and dynamics.

The mass-to-light ratio is the ratio of the mass of a galaxy to its luminosity. It provides insights into the amount of dark matter present in a galaxy, as dark matter does not emit light.

The mass-to-light ratio helps determine the amount of dark matter in a galaxy by comparing the observed luminosity of the galaxy with its estimated mass based on its rotation curve.

MOND (Modified Newtonian Dynamics) is a theory that modifies Newtonian gravity at very low accelerations to explain the observed dynamics of galaxies without the need for dark matter.

Detecting dark matter directly is challenging due to the weak interactions of dark matter particles, their large mass, and their small size, making them difficult to observe with current experimental techniques.

Various methods are being explored to detect dark matter directly, including underground detectors, space-based telescopes, and particle accelerators, each targeting different aspects of dark matter's properties.

Dark matter has profound implications for our understanding of the Universe, challenging our current understanding of gravity, providing insights into the early Universe and its evolution, and influencing the formation and structure of galaxies and galaxy clusters.

Ongoing research efforts related to dark matter include searching for dark matter particles directly, studying the properties of dark matter halos, investigating the role of dark matter in galaxy formation and evolution, and exploring alternative theories that attempt to explain the observed phenomena without the need for dark matter.