Ever wonder why Earth bulges at the equator? That slight oblate spheroid shape—caused by the planet’s spin—may have made higher life possible. Without it, the surface would be so unstable that evolution as we know it might never have happened. | The Randall Carlson

Earth is not a perfect sphere but an oblate spheroid. Its equatorial diameter is 26 miles greater than pole-to-pole —the difference between balance and chaos. That bulge acts like a flywheel, stabilizing the planet’s rotation and keeping the wobble in check. Without it, Earth would drift and tumble. A perfect sphere of equal surface area would measure 7,920 miles across, but the real Earth is shaped for stability. | The Randall Carlson