Although it was recognized as a planet for decades, Pluto is much smaller than the other planets in our solar system and more closely resembles a giant comet nucleus. Consequently, the International Astronomical Union demoted Pluto to the category of dwarf planet, which reflected astronomers’ conclusion that it is a member of the Kuiper belt, a strip of billions of icy bodies orbiting the Sun beyond the orbit of Neptune. What is a “plutino”? Discuss
Source: The Free Dictionary