Dark matter is a hypothetical form of matter that is thought to make up a significant portion of the total mass in the universe. It is called "dark" because it does not emit, absorb, or reflect electromagnetic radiation, making it invisible or "dark" to our current observational methods.
Scientists propose the existence of dark matter based on various astronomical observations. These observations include the gravitational effects of dark matter on the motion of visible matter, such as stars and galaxies, as well as the distribution of matter on larger scales in the universe.
Although dark matter has not been directly detected or identified, its presence is inferred through its gravitational effects. It is believed to interact primarily through gravity, exerting a gravitational pull on visible matter. The presence of dark matter helps explain the observed rotational velocities of galaxies, the distribution of matter in galaxy clusters, and the large-scale structure of the universe.
The exact nature of dark matter remains unknown. It could be composed of particles that have not yet been discovered, often referred to as Weakly Interacting Massive Particles (WIMPs). Several experiments are underway to directly detect these particles or study their potential interactions. However, the search for dark matter continues, and further research and observations are needed to fully understand its properties and role in the universe.