In 1992, the Kuiper Belt was discovered. Similar in form to the Asteroid Belt, it’s around 4.5-7.5 billion kilometres (2.8-4.6 billion miles) from the Sun, is 20 times wider and contains up to 200 times more mass.Where the Asteroid Belt is composed of small rocky minerals and metals, the Kuiper Belt is made up mostly of chunks of frozen methane, ammonia and water ice.
It’s a remnant of the early Solar System and space scientists suspect some comets originate from here. Two moons – Saturn’s Phoebe and Neptune’s Triton – are also suspected to have been planetesimals from the Kuiper Belt. After Pluto was declassified to a dwarf planet in 2006, it became the largest-known feature of the Kuiper Belt, although it was only the second biggest dwarf planet after icy Eris, which is 27 per cent larger than Pluto.