Dark matter is a mysterious, invisible substance that exerts gravitational influence in the universe. Evidence for its existence comes from observations of the motion of galaxies and galaxy clusters.
The gravitational effects observed are much greater than can be accounted for by visible matter (stars, gas, and dust), suggesting the presence of dark matter.
Dark matter is elusive because it doesn't interact with light or other forms of electromagnetic radiation, making it invisible to telescopes. It doesn't emit, absorb, or reflect light, so it remains undetectable through traditional observational methods.
Researchers are actively searching for dark matter using a variety of techniques, including direct and indirect detection experiments.