MO - Phases of the Moon LESSON

Phases of the Moon

 

You probably noticed that the Moon seems to change shape. This is due to the position of the Sun, Earth, and Moon as they move in the Solar System. While the Moon never really changes "shape", we do see different portions of dark and light that give it the appearance of a changed shape. This cycle takes about 29.5 days and is called a Lunar Month.

A synodic period (lunar cycle) is the time required for a given body (in this instance, the Moon) to return to a given position relative to Earth.  This takes 29.5 days.  A sidereal period is the time required for a given body (in this instance, the moon) to return to the same position relative to the sun. This takes 27.3 days.  Remember the new moon occurs when the Sun, Moon, and Earth all align.  All of these celestial objects are constantly moving, and are not in a stationary position.

 

 

 

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