Earth Polar Radius
The Earth's polar radius is the distance from the center of the Earth to the North or South Pole. It measures the Earth’s radius along its rotational axis.
Its value is approximately 6,356.8 kilometers (about 3,949.9 miles).
The Earth is an oblate spheroid, so the polar radius is slightly shorter than the equatorial radius due to the planet's flattening at the poles.
This measurement is crucial for geodesy, understanding Earth’s shape, and satellite navigation.
Key facts:
Polar radius ≈ 6,356.8 km
Smaller than equatorial radius by about 21.3 km
Important for precise Earth modeling and mapping
The difference between the polar and equatorial radius reflects the Earth’s rotation and its effect on the planet’s shape.
Nautical League
A nautical league is a unit of distance once used at sea, mainly by sailors and navigators. It equals 3 nautical miles, which is about 5.56 kilometers or 3.45 miles. Nautical leagues were used to measure longer distances during voyages before modern navigation tools became common. While the nautical mile is still widely used today in maritime and aviation navigation, the nautical league is mostly obsolete and rarely used.