Earth Isn't Perfectly Spherical

The relentless spin of our planet on its axis generates a constant outward force that is strongest along the equator. This force causes Earth's rock and water to bulge out, transforming our world from a perfect sphere into a shape known as an oblate spheroid. This concept was first theorized by Sir Isaac Newton in the 17th century, who reasoned that a rotating fluid body must deform in this way. The effect is substantial enough to be measured: the planet's diameter is about 43 kilometers (nearly 27 miles) wider at the equator than it is from pole to pole, giving it a slightly squashed appearance.

This equatorial bulge leads to a fascinating piece of trivia that redefines our concept of the "highest" point on Earth. While Mount Everest is the tallest mountain measured from sea level, its peak is not