Motions of the Earth

The Earth is in constant motion. You can't feel it, but we see proof of it every day. The sun, moon, and stars seem to rise and set in the sky. The seasons change as well as the amount of the daylight. These events are all caused by the motions of the Earth.


The Earth rotates every day. It spins on its axis. It takes about 24 hours to spin one time around. The rate of movement is about 15 degrees every hour.


The time it takes from one sunrise to the next is called a solar day. This movement is what causes the sun to appear to move across the sky. It "rises" and "sets" every day. There are different periods of sunlight and darkness around the world. When one side of the Earth is facing the sun, it is daytime. On the other side of the Earth, it is night. That side is experiencing darkness because it is facing away from the sun. Our timekeeping system is based on a solar day.


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