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;
Timeline of United States discoveries alcohol 2003 Sedna 2003 Psamathe 2003 Mab 2003 Perdita 2003 Cupid 2004 Orcus 2005 Makemake 2005 Eris Eris, formal designation 136199 Eris, is the largest-known dwarf planet in the Solar System and the ninth-largest body known to orbit the Sun directly. It is approximately 2,500 kilometres in diameter and 27% more massive than the dwarf planet Pluto. Eris was discovered in 2005 at W. M. Keck Observatory by American astronomer Michael E. Brown. 2005 Dysnomia Dysnomia, officially (136199) Eris I Dysnomia, is the only known moon of the dwarf planet Eris. In conjunction of finding Eris, American astronomer Michael E.