Pluto is smaller than the earth's moon, yet has 5 moons of it's own. Pluto's moon Charon is half the diameter of Pluto, which makes it the largest moon relative to its "planet" in our solar system. Pluto was declassified as a planet in August 2006, and was changed to a dwarf planet. Official planets don't share their orbits with other celestial bodies comparable to their size. Pluto, along with other dwarf planets, share orbits with other celestial bodies similar in size.