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The Earth moves in two ways. It moves in a circle around the sun, which is called orbiting, and it spins in a circle around its center, which is called rotating. The average speed of the Earth’s orbit is 29.78 kilometers per second (which is about the same as 66,620 miles per hour). It can sometimes go a little bit slower or a little bit faster as described by Kepler’s second law.

The Earth’s rotation does not have a single speed. Because the Earth is shaped like a ball, the distance around Earth’s surface is different depending how far north or south you are. Because the distance around the surface can be different depending where you are, the speed of rotation is also different.