Is the Earth a perfect sphere?

Equatorial radius = 6378.16 kilometers. Polar radius = 6356.78 kilometers, so the difference in circumference is 71.1 kilometers. It is not a perfect sphere, but kind of pear-shaped.

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All answers are provided by Dr. Sten Odenwald (Raytheon STX) for the
NASA IMAGE/POETRY Education and Public Outreach program.