tenth planet The tenth planet of the Solar System, now known to be Eris (formerly called 2003 UB313). This is the first planet to be discovered orbiting the Sun since Pluto in 1930 and the largest object to be found in the Solar System since Neptune in 1846. Related entry Planet X Related category PLANETS AND MOONS Also on this site: Encyclopedia of Alternative Energy & Sustainable Living Encyclopedia of History Transport Concepts & Designs (partner site) |