What is an exoplanet?

An exoplanet is a planet that orbits a star outside our solar system. These planets can be similar to Earth or completely different—some are rocky, others are gas giants. Scientists search for exoplanets to discover how common planets like ours might be in the universe. By studying exoplanets, astronomers hope to learn if there are other worlds where life could exist or find planets with unique features that teach us more about how planets develop.