Earth and the Moon

Orbit and Rotation

How does Earth spin?

Earth’s spin is mostly the result of angular momentum left over during the formation process of our planet. There are three distinct motions, the most noticeable being Earth’s rotation. Earth rotates once every twenty-three hours, fifty-six minutes, causing our cycles of day and night. Earth also has precession (a wobble of the rotational axis) and nutation (a back-and-forth wiggle of Earth’s axis), caused primarily by the gravitational pull of the Moon as it orbits Earth. Precession and nutation, over long periods of time, cause Earth’s north and south poles to point toward different stars.


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