<Dl> <Dd> Eris (68 AU average) is the largest known scattered disc object, and caused a debate about what constitutes a planet, because it is 25% more massive than Pluto and about the same diameter . It is the most massive of the known dwarf planets . It has one known moon, Dysnomia . Like Pluto, its orbit is highly eccentric, with a perihelion of 38.2 AU (roughly Pluto's distance from the Sun) and an aphelion of 97.6 AU, and steeply inclined to the ecliptic plane . </Dd> </Dl> <Dd> Eris (68 AU average) is the largest known scattered disc object, and caused a debate about what constitutes a planet, because it is 25% more massive than Pluto and about the same diameter . It is the most massive of the known dwarf planets . It has one known moon, Dysnomia . Like Pluto, its orbit is highly eccentric, with a perihelion of 38.2 AU (roughly Pluto's distance from the Sun) and an aphelion of 97.6 AU, and steeply inclined to the ecliptic plane . </Dd> <P> The point at which the Solar System ends and interstellar space begins is not precisely defined because its outer boundaries are shaped by two separate forces: the solar wind and the Sun's gravity . The limit of the solar wind's influence is roughly four times Pluto's distance from the Sun; this heliopause, the outer boundary of the heliosphere, is considered the beginning of the interstellar medium . The Sun's Hill sphere, the effective range of its gravitational dominance, is thought to extend up to a thousand times farther and encompasses the theorized Oort cloud . </P> <P> The heliosphere is a stellar - wind bubble, a region of space dominated by the Sun, which radiates at roughly 400 km / s its solar wind, a stream of charged particles, until it collides with the wind of the interstellar medium . </P>

Earth is largest planet in the solar system