Math in the Natural Sciences

Math in Geology

What is the difference between the Earth’s sidereal and solar days?

The difference between the Earth’s sidereal and solar days has to do with angles and the Earth’s rotation. The mean solar day is equal to 24 hours, or the average of all the solar days in an orbital year. The mean sidereal day is 23 hours, 56 minutes, and 04.09053 seconds. It is not exactly equal to a solar day because by the time the Earth has rotated once, it has moved a little in its orbit around the Sun. Thus, it rotates for about another four minutes before the Sun is considered to be back in exactly the same place in the sky as it was the day before.


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