The new rules say a planet must be “a celestial body that is in orbit around the sun, has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a … nearly round shape, and has cleared the neighborhood around its orbit.” Pluto doesn’t make the cut since its orbit overlaps with Neptune’s.
Read a news story.
Watch a video: Pluto—Does Size Matter?
More about Pluto:
- Pluto Facts and Images
- Photo: Clear View of Pluto
- Pluto (For Kids)More about the solar system:
- Solar System Exploration
- Solar System Simulator
- What’s in the Sky Tonight?
- Solar System JigsawThe astronomers have voted. Now what do you think about Pluto’s demotion?
Image of Pluto and its moon Charon courtesy NASA