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The nautical mile
29 August 2023 · 7 min · 7K views
What this video covers
One nautical mile equals exactly 1,852 meters because it corresponds to one arc-minute of latitude along a meridian on Earth's surface.3:00 The explanation works through the geometry: Earth's radius is 6,370 km, giving a circumference of roughly 40,003.6 km; divide by 360 degrees, then by 60 minutes per degree, and the result is 1.852 km.4:21 The nautical mile has no connection to Anglo-Saxon units such as the U.S. statutory mile (1,609 meters), which descends from the Roman "milia passum" — a thousand paces, each pace defined as the distance between successive placements of the same foot, approximately 1.48 meters in Roman times.0:44 The nautical mile's value comes entirely from the coordinate system used to describe positions on a sphere: latitude and longitude express distances as angles, and one arc-minute of a great circle is the natural unit for that system.3:00 The symbol NM (Nautical Miles) is the most widely accepted abbreviation, though no single international standard has been formally adopted.0:34 The full arithmetic is shown step by step, allowing sailors to verify the derivation themselves.
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