An exoplanet, or extrasolar planet, is a planet that orbits a star outside our solar system. These celestial bodies can vary widely in size, composition, and distance from their host stars. Scientists have discovered thousands of exoplanets using various methods, including the transit method and radial velocity method. Exoplanets can be classified into different categories, such as gas giants, terrestrial planets, and super-Earths. Some exoplanets are located in the habitable zone, where conditions might allow for liquid water, raising the possibility of life beyond Earth. The study of exoplanets helps astronomers understand the diversity of planetary systems in the universe.