https://www.atlasobscura.com/articles/strange-maps-uneven-gravity “The earth is not perfectly round: It’s flatter nearer to (and flattest at) the poles and bulges more towards (and most along) the equator. As a result, the distance from the earth’s center to sea level is 13 miles (21 km) greater at the equator than at the poles. The latitude you’re at has an effect on #gravity with polar and equatorial extremes: Newton’s apple (and you) weigh 0.5% more at the poles than at the equator.”