The Kuiper belt (pronounce /ˈkaɪpɚ/, to rhyme with "viper"), sometimes called the Edgeworth-Kuiper belt, is a region of the Solar System beyond the planets extending from the orbit of Neptune (at 30 AU) to approximately 55 AU from the Sun. It is similar to the asteroid belt, although it is far larger; 20 times as wide and 20–200 times as massive. Like the asteroid belt, it consists mainly of small bodies (remnants from the Solar System's formation) and at least one dwarf planet – Pluto. But while the asteroid belt is composed primarily of rock and metal, the Kuiper belt objects are composed largely of frozen volatiles (dubbed "ices"), such as methane, ammonia and water.