Pluto

Pluto is a dwarf planet in our Solar System. It is made of rock and ice. It is very cold on Pluto with temperatures between -218°C and -240°C.

Pluto is 2390 kilometres across. That's about two-thirds as wide as the Moon and about one fifth as wide as the Earth.

Pluto is thirteen million million million tonnes in mass. The Earth has about 460 times the mass of Pluto; the Moon has about five and a half times the mass of Pluto.

Clyde Tombaugh found Pluto in 1930. Pluto was named after the Roman god of hell. This name was suggested by Venetia Burney from England. She was eleven years old at the time.

Pluto has three moons: Charon, Nix, and Hydra. Charon is 1190 km across, half as wide as Pluto. Charon is about 19,410 km away from Pluto. Pluto and Charon spin around each other making the two look like a double dwarf planet. Nix and Hydra are much smaller, about 45-160 km across, about 44,000 km from Pluto.

There are eight planets in the Solar System. Pluto is very different from these eight planets. It is smaller than them and follows a different kind of path around the Sun. Pluto sometimes gets closer to the Sun than Neptune, because of the path it follows.

Mercury is the Solar System's smallest planet. Mercury is about twice as wide as Pluto. Mercury has about twenty-five times the mass Pluto.

We used to call Pluto the ninth planet. However, in August, 2006 the International Astronomical Union said that Pluto should not be called a planet anymore. They said that it should be called a dwarf planet instead; and it now is called a dwarf planet.

The Solar System

Star: The Sun
Planets: Mercury • Venus • Earth • Mars • Jupiter • Saturn • Uranus • Neptune
Dwarf planets: Ceres • Pluto • Eris
Small solar system body: Asteroid belt • Comets • Meteors • Kuiper belt • Scattered disc • Oort cloud
Other: Moon