Which planet is the smallest?

This week, the Inquisitive Iguanas researched what the smallest planet is. The answer is more complicated than you might think, because Pluto is smaller than Mercury, but Pluto isn't considered a real planet by scientists. It's just considered part of the Kuiper belt which has many other space iceballs like Pluto in it (similar to the asteroids in the asteroid belt.) So that leaves Mercury as the smallest true planet. Its diameter is 3,031 miles, about 1/3 the size of Earth. Pluto's diameter is only 1,482 miles. So if you still count Pluto as a planet, it would be the smallest one!

Here are our Internet sources about the smallest planet:
What is the Smallest Planet in the Solar System?, Views of the Solar System: Mercury, Wikipedia: Mercury, and Pluto Is Not A Planet.

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