Transit photometry is a method used in astronomy to detect exoplanets by observing the brightness of stars. When a planet passes in front of its host star, it blocks a small portion of the star's light, causing a temporary dip in brightness. By measuring these dips, astronomers can infer the presence of a planet and gather information about its size and orbit. This technique is particularly effective for finding exoplanets that are close to their stars, as the transit events are more frequent and noticeable. Missions like Kepler and TESS have utilized transit photometry to discover thousands of exoplanets, expanding our understanding of planetary systems beyond our own.