The moon phase or Moon cycle, also known as the lunatic phase, is the phase of the Moon as seen from Earth. The moon appears to rotate about its axis in a counter-clockwise direction as it moves through each lunar cycle. As the Moon rotates, it waxes and wanes and sometimes even completely waxes out. This waxing and waning also affect the Moon phases in a global sense, since the waxing Moon phases become a new Moon every year.
When the Moon appears in the sky, it is
always illuminated by the Sun in its usual place in the sky. As the Moon
revolves around the earth in its orbit, the Moon appears to move back and forth
between the Sun and the inner side of the earth. As the Moon circles the earth,
it appears closer to the inner side while moving further from the Sun as it
revolves. The Moon appears to be slightly darker at the new Moon and brighter at the full Moon. The phases also tend to differ from the usual cycle of the Moon
phases, which is a cycle of a Moon and a half and a Quarter which takes 9 months
to two years for the full Moon to pass.
The Moon appears to move around the earth
in different ways at different times. It seems to be pulled along by the Sun in
its orbit as it whips around the globe. As the Moon spirals around the earth,
the effects are felt in the northern and southern hemispheres and the Moon
appears to be affected by the seasons. It is during some of these phrases that
people are prone to be astounded by what they see in the night sky.
The Moon moves around the planet in much
the same way that the planets move around the sun. The only difference is that
the Moon moves with a slightly slower orbital speed and therefore travels more
slowly around the planet than does the sun. It takes about half a day for the
Moon to circle the earth twice. So the daily Moon Phases that we have become
accustomed to doing indeed seem to occur twice each year.
The Moon's daily phase cycle is known as
the lunar cycle or the new moon phases. There are actually eight phases, but
for simplicity, we generally refer to the annual new moon in our discussions
here. There are four waxing moon phases. These are: the first is called the
re-awakening when the Moon begins to wax and then completely open for a short
time. This generally is followed by the beginning of the New Moon, which is a
period of mostly softness and pinkish darkness.
The next of the four waxing moon phases is
the First Quarter, which is often referred to as the initial grazing. This
lasts from the first day (crescent) of the New Moon to the first day (moon) of
the full Moon. It is characterized by the Moon being very bright and the sky is
very dark. In the northern hemisphere, we see the crescent waning in the east
and slowly moving west until it nearly reaches the horizon at the end of the
New Moon. The thin crescent phases represent the first year of a new phase.
Then there is the first gibbous Moon, also
called the first New Moon. It occurs when the Moon is slightly farther from the
Earth than it was at the first New Moon. At this time the Moon is about halfway from the horizon. When it is closest to the Earth, the Moon is about the
same size and shape as it was at the New Moon and so the gibbous Moon
represents the last stage of a waning gibbous phase. The Moon will wax and wane
several times during the year, depending on the position of the Sun in the sky,
the Moon phases during the New Moon, and the Moon phases at full and new Moon.
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