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Planet Nine

space Maturity 11-13 Next article →

Some people think a big world is out there. It stays far away in the dark. We cannot see it yet. It might help us learn more. It is a big mystery. Do you think it is there?

38 words

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What is Nepedia?

A free, ad-free encyclopedia for children. Every article is written at five reading levels, so the same page works for a five-year-old and a fifteen-year-old — use the level switcher above to see this one change. No account needed to read.