An exoplanet is a planet that orbits a star other than our Sun. While the eight planets in our solar system (Mercury through Neptune) circle our Sun, exoplanets circle distant stars scattered throughout the universe.

For most of human history, we could only wonder if other planets existed beyond our solar system. Then in 1992, scientists discovered the first confirmed exoplanets, and suddenly we knew: our solar system isn't unique. Since then, astronomers have found thousands of exoplanets, each one orbiting a far-off star.

Some exoplanets are massive gas giants larger than Jupiter. Others are small and rocky like Earth. Scientists have found exoplanets that orbit incredibly close to their stars, completing a full year in just a few Earth days, and others that drift in frozen darkness far from any warmth. Some orbit two stars at once, meaning they'd have double sunsets like the planet Tatooine in Star Wars.

Discovering exoplanets helps scientists understand how planets form and whether life might exist elsewhere in the universe. Each new exoplanet discovery reminds us how vast and varied the cosmos really is.