Monthly Cycle
As
you
know, the moon rises in the east and sets in the west, then rises again
the
next night. This is the monthly cycle, caused by the moon revolving
eastward or
counter-clockwise around the earth. This period of time takes 29.5 days
to
compete, or one month. There is not much precision in the monthly calendar- February
has
28-29 days, and December has 31 days, but that’s the way it
is. Our satellite,
the moon, revolves around the sun, but rotates on its own axis at the same time. By some
freak in
celestial nature, the time it takes for the moon to rotate and revolve
is the
same, which is why we always see only one side of the moon. For a full
moon, the earth's shadow must fall on the moon; and as for a new moon,
the sun's light must fall fully on the moon. Below are two
diagrams: the first showing the revolution of the moon around the earth, and the other showing the full/new moon.
