We begin a new chapter, called, dwarf planets. The first is Eris. This dwarf planet is the most massive dwarf planet in the Solar System. It also has a satellite called Dysnomia. This dwarf planet is more massive than Pluto, being after the planets, the next celestial body as a mass, so if it were a little bigger, maybe it was the planet. Many believe that it formed between Neptune and Uranus, after some disturbances. But it is certain that this dwarf planet is in the Kuiper belt, after Nepune. So, if it formed as you heard above, it means that it was propelled further. Before being given this name and being officially declared the dwarf planet, it was previously considered an asteroid, under the name 2003 UB313.