 In response, the International Astronomical Union (IAU) was forced to define what a planet is for the first time, and in so doing included in their definition that a planet must have "cleared the neighbourhood around its orbit".As Pluto shares its orbit with many other sizable objects, it was deemed not to have cleared its orbit, and was thus reclassified from a planet to a dwarf planet, making it a member of the Kuiper belt.Although Pluto is currently the largest known KBO, there is at least one known larger object currently outside the Kuiper belt that probably originated in it