The Moon
The moon is often considered a satellite of the Earth an travels round once every
27.4 days at an average distance away of about 400 000km. It also spins on its own axis
and thus has the same side facing the earth. As such, we never see the dark side of the
moon. We are only able to see the moon due to refleted light rays from the sun. Neither
has the moon a gravitational field nor has it a separate atmosphere of its own. That is
why we see astronauts on space expeditions 'floating'.
The Periodic Phases of the moon
How the moon appears from the earth changes during its
journey within a month ; and changes in subsequent months. Thus, we refer to that as the
moon having different phases. The following diagram graphically illustrates how the moon
appears as seen from the earth during its monthly orbitals.
