Explore how future space missions will search for planets—and even asteroids and moons—around distant stars.
Astronomers have used many different methods to discover planets beyond the solar system, but the most successful by far is transit photometry, which measures changes in a star's brightness caused by a mini-eclipse. When a planet crosses in front of its star along our line of sight, it blocks some of the star's light. If the dimming lasts for a set amount of time and occurs at regular intervals, it likely means an exoplanet is passing in front of, or transiting, the star once every orbital period. NASA’s Kepler Space Telescope has used this technique to become the most successful planet-hunting spacecraft to date, with more than a thousand established discoveries and many more awaiting confirmation. Employing this same technique, upcoming missions carrying improved technology will continue the search for new worlds—including possible moons, planetary rings and asteroid groups—by monitoring hundreds of thousands of nearby stars for telltale transits. Watch the video to learn more.