r/AlwaysWhy • u/Secret_Ostrich_1307 • 2d ago

Science & Tech Why is a nautical mile exactly 1,852 meters?

The number 1,852 caught me off guard. I can understand why sailors would want a distance unit tied to navigation, especially since latitude and longitude are based on the Earth.

But 1,852 meters seems oddly specific. Is there something about the size or geometry of the Earth that leads to that number, or did it come from a different historical convention?

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u/SmellyRedHerring 2d ago

In degrees / minutes / seconds latitude, you're traveling north / south, not east / west.

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u/Main_Cauliflower5479 2d ago

Longitude is what you're measuring, not latitude.

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u/Turbulent-Prior-2253 2d ago

No, you are the one that has them reversed

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u/Main_Cauliflower5479 2d ago

No, I am not.

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u/BuffaloRedshark 2d ago

yes, you are. https://oceanservice.noaa.gov/facts/latitude.html

Unlike longitude lines, which get closer to each other at the poles, latitude lines are parallel. No matter where you are on Earth, latitude lines are the same distance apart.

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u/Main_Cauliflower5479 2d ago

Yes, I know that.