How Long Does It Take the Moon to Complete One Revolution Around the Earth?
The Moon revolves around the Earth every 27 days, 7 hours and 43 minutes. This time period is known as a sidereal month. It is measured by following the Moon's position in relation to distant stars that remain in fixed positions in the sky.
The Moon orbits the Earth in an elliptical orbit, not a perfect circle. It moves west to east, or counterclockwise, if looking down from the North Pole. It travels at an average speed of 2,288 miles per hour, but it moves at different speeds at different times during its orbit. When it's closer to Earth, it moves faster, and when it's farther away, it moves slower. In one orbit, the Moon travels about 1,423,000 miles around the Earth.
Although the Moon orbits the Earth in about 27 days, it takes 29.5 days for the Moon to cycle through all its phases. The time it takes for the Moon to go through a cycle of phases is known as a synodic month. The difference in orbit times occurs because the Moon orbits the Earth as the Earth orbits the Sun. This means the Moon must travel a bit farther on its path to make up for the additional distance and complete its phase cycle.