Dark matter is a hypothetical form of matter that does not interact with light or other forms of electromagnetic radiation. Its existence is inferred from its gravitational effects on visible matter and the large-scale structure of the universe. While the exact nature of dark matter remains unknown, there are several theories and models that attempt to explain its properties.
One prevailing hypothesis is that dark matter consists of particles that do not interact electromagnetically but have mass and interact gravitationally with other matter. These particles are often referred to as Weakly Interacting Massive Particles (WIMPs). WIMPs are postulated to be stable and slow-moving, making them difficult to detect directly. Researchers have been conducting experiments, such as using underground detectors or particle colliders, in an effort to observe and identify these particles indirectly through their interactions with ordinary matter.
Another theory suggests that dark matter could be composed of primordial black holes—tiny black holes that formed shortly after the Big Bang. These black holes would have a gravitational effect on visible matter without emitting significant amounts of radiation.
As for the interaction of dark matter with known forces and particles, it is primarily through gravitational interactions. Dark matter's gravitational pull is thought to contribute to the observed rotational curves of galaxies, the formation of large-scale structures in the universe, and the gravitational lensing of light. However, it does not interact electromagnetically, which means it does not emit, absorb, or reflect light, making it difficult to directly detect or observe.
Despite extensive efforts, dark matter remains elusive, and its exact composition and interaction mechanisms remain uncertain. Ongoing research, both theoretical and experimental, continues to explore these mysteries in order to deepen our understanding of the universe's composition and evolution.