The NASA/ESA Hubble Space Telescope has measured the largest object in the solar system ever seen since the discovery of Pluto 72 years ago. Approximately half the size of Pluto, the icy world is called 'Quaoar' (pronounced kwa-whar). Quaoar is about 4 billion miles away (about 6.4 billion kilometres away), more than a billion miles farther than Pluto. Like Pluto, Quaoar dwells in the Kuiper belt, an icy belt of comet-like bodies extending 7 billion miles beyond Neptune's orbit.