The Kuiper belt is similar to the asteroid belt I talked about earlier. It is a giant accumulation of frozen gasses and asteroids, orbiting the Sun at a greater distance than Neptune.
A visualization of the Kuiper belt. Credit: NASA
The Kuiper belt has a diameter which is about 20 times as big as the Asteroid belt and it holds about 20 to 200 times more mass. The largest object in the Kuiper belt is the dwarf planet Pluto and it's located about 30-50 AU From the Sun (1 AU = the distance between the Earth and the Sun, about 150 million km).
Since Neptune is located where the Kuiper belt begins, it has a large effect on its structure due to Neptune's gravity, which can swing objects from the belt towards the inner solar system. It is thought that Neptune's moon - Triton - was captured from the Kuiper belt, as it's the only known moon in our Solar System with a retrograde orbit (an orbit into the opposite direction of the planet's rotation). The precise origin of the Kuiper belt is still unclear, but it's generally assumed to be remnants of the creation of the solar system.
A colorized image of Triton, assumed to have its origins in the Kuiper belt, taken by Voyager 2 spacecraft on 1989. Credit: NASA
On 2005 the first spacecraft to explore the Kuiper belt was launched, called New Horizon. It passed Pluto on the 14th of July, 2015.
The New Horizon space probe sent out to explore the Kuiper belt. Credit: NASA
After completing its flyby of Pluto, the New Horizon spaceprobe is now underway to the Kuiper belt object PT 1 2014 MU69, and it's expected to arrive there on January 1, 2019, at a total distance of 43.4 AU from the Sun, giving us much more information on the Kuiper belt.
The trajectory of the New Horizon space probe. Credit: NASA
Thanks for reading this short article on the Kuiper belt. In the next post we will discuss the Oort Cloud so if you though this was interesting, be sure to follow!