What is dark matter?

Dark matter is a hypothetical form of matter that is thought to account for approximately 85% of the total matter in the universe. Unlike ordinary matter, it does not emit, absorb, or reflect light, making it invisible to telescopes and other instruments that detect electromagnetic radiation.

The existence of dark matter was first proposed in the 1930s by Swiss astronomer Fritz Zwicky, who observed the movements of galaxies in the Coma Cluster and concluded that there must be a significant amount of unseen mass present in the cluster. Since then, various astronomical observations and calculations have suggested the presence of dark matter in the universe.

Although the nature of dark matter is still not well understood, it is believed to be composed of some kind of non-baryonic particle that interacts weakly with ordinary matter. Scientists have proposed a number of different particles that could make up dark matter, including axions, WIMPs (weakly interacting massive particles), and sterile neutrinos, among others.

The study of dark matter is an active area of research in astrophysics and cosmology, as it is thought to play a crucial role in the structure and evolution of the universe. Understanding its properties and nature could help scientists better understand the formation of galaxies, the large-scale structure of the universe, and the ultimate fate of the cosmos.