Is there an evidence that proves dark matter exists?
While dark matter has not been directly detected, there is strong indirect evidence that supports its existence. Dark matter is a hypothetical form of matter thought to account for about 27% of the total mass-energy content of the universe. It does not emit, absorb, or reflect light, making it difficult to observe directly. However, its gravitational effects on visible matter, galaxies, and large-scale cosmic structures provide compelling evidence for its existence. Some key pieces of evidence include:

- Galaxy rotation curves: The speeds at which stars and gas rotate around the centers of galaxies are higher than expected based on the visible mass alone. This discrepancy can be explained if there is a significant amount of unseen mass (dark matter) exerting gravitational force on the visible matter.
- Gravitational lensing: When the light from a distant galaxy passes through a massive foreground object, like a galaxy cluster, the light is bent by the gravitational influence of the intervening mass. This effect, known as gravitational lensing, is stronger than expected based on the visible mass of the lensing object, suggesting the presence of dark matter.
- Cosmic microwave background (CMB) radiation: The CMB is the leftover radiation from the early universe, and its fluctuations provide information about the composition of the universe. The CMB data supports the existence of dark matter, as it helps explain the observed distribution of temperature variations.
- Large-scale structure formation: The distribution of galaxies and galaxy clusters in the universe is influenced by gravity. Simulations of structure formation that include dark matter produce results that are consistent with observed large-scale structures.
- The Bullet Cluster: The Bullet Cluster is a pair of colliding galaxy clusters where the observed distribution of mass, inferred from gravitational lensing, is separated from the visible matter, primarily in the form of hot gas detected via X-ray observations. This separation provides strong evidence for the existence of dark matter.

While these observations provide significant evidence for dark matter, its exact nature remains unknown. The leading hypothesis is that dark matter is composed of weakly interacting massive particles (WIMPs), which have not yet been directly detected. There are ongoing experiments and observations aimed at understanding the nature and properties of dark matter.