Double planet frequently been described by many scientists as "double dwarf planets" ("double planets" prior to the 2006 definition of "planet"). The International Astronomical Union (IAU) currently calls Charon a satellite of Pluto, but has explicitly expressed a willingness to reconsider the bodies double dwarf planets at a future time. The Moon-to-Earth mass ratio of 0.01230 (≈ ) is also notably close to 1 when compared to all other satellite-to-planet ratios. Consequently, some scientists view the Earth-Moon system as a double planet as well, though this is a minority view. Eris's lone satellite, Dysnomia, has a radius somewhere around that of Eris;
Eris (dwarf planet) decide the issue. This was announced as the IAU's "Definition of a Planet in the Solar System," adopted on 24 August 2006. At this time, both Eris and Pluto were classified as "dwarf planets," a category distinct from the new definition of "planet." Brown has since stated his approval of this classification. The IAU subsequently added Eris to its Minor Planet Catalogue, designating it "(136199) Eris." Eris has an orbital period of 558 years. Its maximum possible distance from the Sun (aphelion) is 97.65 AU, and its closest (perihelion) is 37.91 AU. It came to perihelion between 1698 and 1699,