GCSE Physics

Odd one out

Pluto is the odd one out. Some even say that it isn't a planet because it is smaller than the Moon.

Pluto is comparable to an inner planet in density and rockiness, but, having an elliptical orbit ranging from 30 to 50 AU from the Sun, its average surface temperature is -230 °C.

Pluto's orbit compared with Neptune's

Note how Pluto's elliptical orbit loops inside Neptune's.

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