A planet that orbits a star other than our Sun, also called an extrasolar planet. These worlds come in a stunning variety of sizes, compositions, and orbital characteristics that challenge our understanding of planetary formation.
From Greek 'exo' meaning 'outside' combined with 'planet,' first used in the 1990s as discoveries of these worlds began. The term gained widespread use after the first confirmed exoplanet around a main-sequence star was found in 1995.
Try Another Word