A Wonderleaf question
Why is Pluto not a planet anymore?
a real page from the book
Pluto is not counted as a planet now because astronomers changed the definition in 2006. A planet must orbit the Sun, be rounded by its own gravity, and dominate its orbital zone. Pluto meets the first two rules, but it shares space with many Kuiper Belt objects.
Nothing happened to Pluto itself. It is still a round, icy world circling far beyond Neptune, with moons and a famous heart-shaped region on its surface. The change was about classification: scientists found more distant bodies and needed names that sorted them more clearly.
Wonder words
- orbit
- gravity
- kuiper
- classification
Try it out
Line up household objects as planets, then add several small objects near Pluto to show its crowded neighborhood.
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Watercolour scenes, straight answers, about three minutes cover to cover.
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