Dark matter is a mysterious substance that makes up about 27% of the universe. It doesn't emit, absorb, or reflect light, so it's invisible to telescopes. Scientists know dark matter exists because of its gravitational effects on galaxies and galaxy clusters. One way scientists study dark matter is through gravitational lensing, where the light from distant galaxies is bent by the gravity of dark matter. Another method is through particle detectors, which search for interactions between dark matter particles and ordinary matter. While the properties of dark matter are still unknown, it's believed to be cold, non-baryonic, and non-interacting. Astrophysicists continue to study dark matter to understand its role in the structure and evolution of the universe. The existence of dark matter remains one of the biggest mysteries in physics, and unlocking its secrets could revolutionize our understanding of the cosmos.