Pluto

Overview

Pluto is a dwarf planet in our solar system. It was once considered the ninth planet, but was reclassified as a dwarf planet in 2006 by the International Astronomical Union (IAU).

Physical Characteristics

• Pluto is smaller than Earth's moon, with a diameter of about 1,491 miles (2,392 kilometers).
• It has a thin atmosphere primarily composed of nitrogen, with traces of methane and carbon monoxide.
• Pluto has five known moons, the largest of which is Charon.

Orbit and Rotation

• Pluto has a highly elliptical orbit that takes it closer to the sun than Neptune for a period of time.
• It takes about 248 Earth years for Pluto to complete one orbit around the sun.
• Pluto's rotation period is about 6.4 Earth days.

Exploration

Pluto was visited by the New Horizons spacecraft in 2015, providing the first close-up images and scientific data of the dwarf planet and its moons.

Study Guide Questions

1. What is the current classification of Pluto in our solar system?
2. What is the diameter of Pluto?
3. What are the primary components of Pluto's atmosphere?
4. How many known moons does Pluto have?
5. How long does it take for Pluto to complete one orbit around the sun?
6. When was Pluto visited by the New Horizons spacecraft?