The Kuiper belt is a belt consisting of millions of small icy fragments, situated beyond Neptune orbit, surrounding the Solar System. It is believed to be made up of remnants, or debris, from the Solar System formation. These icy remnants are composed of frozen ammonia, water, and methane. Each one of these objects has an average diameter of 100 km. The Kuiper belt lies at 54 astronomical units from the Sun, with one astronomical unit being the equivalent of 93,000,000 miles. It is named after Gerard Kuiper (1905-1973), American astronomer.