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Which one of these is not a planet?
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Earth
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Pluto
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Mars
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Saturn
That's Correct!
It's Wrong!
Pluto is not considered a planet anymore because in 2006, the International Astronomical Union (IAU) redefined the definition of a planet. According to the new definition, a planet must clear its orbit of other debris, and Pluto does not meet this criterion as it shares its orbit with other objects in the Kuiper Belt. Therefore, Pluto is now classified as a dwarf planet.
