Pluto is unique in many ways. It orbits the Sun slower than any other planet. Its orbit is also the most eccentric. Pluto's orbit has the largest inclination to the ecliptic. It is the coldest planet in the solar system. Pluto has one known moon, Charon. Charon is more than half Pluto's size. Charon is closer in size to the planet it orbits than any other moon. Pluto and Charon are sometimes called a double planet.
