A vast reservoir of icy bodies in the region of the solar system beyond the orbit of the planet Neptune. The trans-Neptunian region of the solar system was thought to be home only to the small planet Pluto and its satellite Charon until the discovery of the Kuiper Belt object 1992 QB₁ in 1992 by David Jewitt and Jane Luu. Members of the belt (Kuiper Belt objects, or KBOs) are part of the original building blocks (planetesimals) of the outer planets, left behind simply because they were not incorporated into planets or ejected from the solar system. They are thus relics from the solar nebula, the original disk of gas and dust that gave rise to everything in the solar system. As such, Kuiper Belt objects should preserve records of the early stages of the solar system's evolution.