PLUTO THE DWARF PLANET

Key Facts & Summary

• Pluto is the ninth-largest and tenth most massive known object directly orbiting the Sun.

• It is the first Kuiper Belt object to be discovered and it is the largest known plutoid.

• Pluto was discovered in 1930 by Clyde Tombaugh.

• Pluto was classified as a planet for 75 years. It held the title of the ninth planet of the Solar System.

• Pluto was declassified from the status of planet to that of a dwarf planet in 2006 after another dwarf planet, Eris was discovered.

• The controversial classification of Pluto forced the scientific community to come up with the definition of a planet.

• Pluto is primarily made out of ice and rock. It is relatively small even when compared to Earth’s Moon, being one-sixth of the moon’s mass, and one-third of its volume.

• Pluto has an unusual orbit that takes it closer to the Sun than the farthest planet Neptune, but also, it takes it farther from the Sun than Neptune’s position.

• Pluto has five known moons: Charon, Styx, Nix, Kerberos, and Hydra.

• Pluto’s moon Charon is the largest, having around half of Pluto’s diameter.

• Charon is the biggest known moon of any dwarf planet.

• Pluto has a radius of 1.185 kilometers / 737 miles, thus it is 1/6 the width of Earth and a diameter of 2.326 km / 1.445 mi.

• Pluto has mountains, valleys, and craters. The surface temperatures vary from -375 to – 400 degrees Fahrenheit / – 226 to – 240 degrees Celsius.

• Pluto is one third made out of water. Its atmosphere is very similar to that of a comet since it collapses as it moves away from the Sun, and expands as it gets close.

• Pluto doesn’t seem to have a magnetic field.