The nautical mile in the United Kingdom, as in most countries, follows the international standard, which is approximately equal to 1.852 kilometers or 1.15078 statute miles (land miles). This international standard for the nautical mile is used for maritime and aviation navigation in the UK, as well as in many other countries around the world.
To provide some context, the nautical mile is based on the Earth's circumference and is defined as one minute of latitude along a meridian. It is commonly used in navigation because it provides a consistent and convenient way to measure distances at sea and in the air, where latitude is an essential factor. The use of the international nautical mile ensures compatibility and consistency in maritime and aviation operations across different regions and countries.
Earth's equatorial radius, often denoted as "R," is the distance from the center of the Earth to the point on the Earth's surface that lies along the equator. It represents the Earth's average radius when measured from its center to its equatorial surface. The equatorial radius is greater than the polar radius because the Earth is slightly flattened at the poles and bulges at the equator due to its rotation.
The approximate value for Earth's equatorial radius is about 6,378.1 kilometers (or approximately 3,963.2 miles). This value may vary slightly depending on the reference ellipsoid used for modeling the Earth's shape, but the given value is a commonly used and accurate approximation for most purposes.
In contrast to the equatorial radius, Earth's polar radius (measured from the center to a point on the Earth's surface at the North or South Pole) is slightly shorter, approximately 6,357 kilometers (3,949 miles).