# If coordinates use minutes and seconds because of the Earth’s rotation, what do they use for other planets and why?

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If coordinates use minutes and seconds because of the Earth’s rotation, what do they use for other planets and why?

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Coordinates use minutes and seconds because that’s how we chose to divide angles into smaller segments. It is because earth is round, and has nothing to do with earth’s rotation.

You can still use those. As long as the other planet is reasonably close to a sphere, then we can say it’s 360 degrees around it in latitude or longitude, and a minute of arc will still be 1/60 of a degree and a second of arc will still be 1/60 of a minute of arc. (Nothing to do with time.)

The distance on the ground that each of those represents will differ, depending whether the other planet is bigger or smaller than Earth (or maybe, by a miracle, exactly the same size) but the arc measurements make sense for any fairly-round thing.

They don’t use minutes because of earths rotation.

Then we would need to split earth in 24 hours first to make it match rotation, but we split it in 360 degrees before.

“Minute” just means “reduced” (related to “minor”) while seconds are named like that because they are the second time you divide by 60. (Originally called Minuta Secunda in Latin)

So both just mean “divide by 60” once or twice wich is the base of the babylonian number system.

This was a thing that the Babylonians sort of got wrong. A circle is 360 degrees but a day (one revolution of the Earth) is 24 hrs. So, one degree of longitude, on average, corresponds to 4 minutes time difference and 1 minute longitude is 4 seconds time.

We don’t use minutes and seconds because of earth rotation.

Degrees of an angle are subdivided into minutes and seconds just like hours are. They are unrelated to the rotation of the planet.

The earth turns once in 24 hours but is divided into 360 degrees. There are 15 times as many degrees in a circle as there are hours in a day, so the world turns by 15 arcminutes per minute or 15 arcseconds per second.

The division of a degree in to 60 minutes has the advantage that 60 is divisible by a lot of integers, you can divide a degree into 2, 3, 4, 5, 6 and get a whole number of minutes. That can be useful.

In modern use the whole minutes and seconds has fallen a bit out of use and decimal subdivision are frequently used. Both are valid.

Coordinate system on other planets like Mars for example follow the same rules as on earth.