Kepler is a space observatory launched by NASA in 2009, designed to discover Earth-sized planets orbiting other stars. It uses the transit method, which detects dips in a star's brightness caused by a planet passing in front of it. Over its mission, Kepler identified thousands of potential exoplanets, significantly advancing our understanding of planetary systems. The mission was named after the German astronomer Johannes Kepler, who formulated laws of planetary motion in the early 17th century. Kepler's work laid the foundation for modern astronomy, helping scientists understand how planets move in relation to their stars. The observatory operated until 2018, contributing valuable data to the field.