Exoplanets shown in comparison to the size of the earth. An exoplanet (or extra solar planet), is a planet that orbits a star other than the Sun. The first scientific detection of an exoplanet was in 1988. The first confirmed detection came in 1992; since then, and as of 1 February 2017, there have been 3,572 exoplanets in 2,682 planetary systems and 602 multiple planetary systems confirmed.