Why isn’t Earth perfectly round?

If you had an enormous measuring tape that started at Earth’s center and went to our planet’s highest peak, you wouldn’t be looking at Mount Everest. Rather, the tallest mountain would be on the other side of the world: Ecuador’s Chimborazo.

Chimborazo wins in this case because Earth is actually a little squished at the poles, like a person pressing both hands on the top and bottom of a ball. As a result, the equator — where Ecuador sits — juts out. Rather than a perfect sphere, Earth is “oblate,” meaning it’s shaped like a slightly flattened sphere.