Dwarf Planet Eris

Eris, 136 199 Eris, is the largest known dwarf planet and for now the largest body found in Kuiper Belt. Although his discoverers initially declared him as the tenth planet in the solar system, the discovery of this object is, in addition to the long debate over whether Pluto is a planet at all, encouraged to redefine the concept of the planet in August 2006th by the International Astronomical Union, which along with Pluto Eris was classified into the category of dwarf planets. Eris distance from the Sun is 97 AU and has a diameter between 2400 and 3000 km, and mass about 1.66x10²² kg (27% larger than Pluto). The news of the discovery was announced on 29 July 2005. It is believed that this body is made of stone and ice.
His route is very elongated. At a time when is closest to the Sun it is inside Pluto's orbit, and when is the farthest, it is almost three times further than Pluto. Object 2003 UB313 named Eris go around the sun every 560 Earth years. Unlike the other planets whose paths lie almost in the plane of ecliptic, the path of "tenth" planet is tilted 45 degrees in relation to that plane. In October 2005th was discovered that he has a small companion named Dysnomia.
Shortly after the discover of this planet among astronomers began a new debate whether these objects are new planets or just one of them, or maybe none? Moreover, many people became clear that this discovery did not get the tenth planet, but we lost the ninth, because Pluto because of its elongated and inclined tracks and modest-sized is not planet.