How long is the rotation of the earth?
• The length of one rotation of the earth is one “earth day”; the length of one rotation of the moon is one “lunar day,” and they are not necessarily the same. • Revolution refers to the orbit of one body around another. • How long is one revolution of the earth around the sun? • The length of one revolution of the earth around the sun is one “year”; the length of one revolution of the moon around the earth is one “month.” • The diagram below shows the Earth and Moon as viewed from space far above the north pole of the Earth. • Stand in the noon position with the moon held at arm length in the direction of the sun, as in #1. (The arrows coming from the right represent light rays from the sun.) • Identify a mark on your moonball (such as a sporting brand label on a baseball or golfball) and turn the moon so that this mark is facing you. Let the marked side always represent the “near side” of the moon. • At position #1, is the marked side (near side) the same as the bright side? • At pos
