The Moon doesn’t emit any light of its own. It shines
because it reflects light that it receives from the Sun. As the
Moon circles
the Earth, rays of sunlight strike its surface and illuminate different
portions of its face. At that point in its journey, when it lies
directly between the Sun, and us the Moon cannot reflect any light
back to Earth since the Sun’s rays strike the face of the
Moon that is pointing away from us. This renders the Moon invisible
from
Earth. |
As the Moon moves out of direct line and begins to move around
the Earth, the Sun’s light strikes at an angle. The first sign
of the New Moon, a slender silver eyelash in the darkened sky, begins
to appear. This is the start of the Moon’s waxing phase and,
from now, as more and more of its face is illuminated by the Sun,
the Moon appears to increase in size each night until it reaches
halfway around the Earth. At this point, the Moon is at its farthest
from the Sun, in direct opposition, so that its whole face is lit
up by sunlight. In this position, it is the Full Moon that is seen
from the Earth.
From here, the Moon begins the second half of its journey around
the Earth. As it sweeps around us in its approach to the Sun, it
reverses its phases and, with less and less of its face lit up by
the Sun, it appears to wane, or decrease. It wanes from Full to Last
Quarter, to the Crescent and finally to invisibility again when it
aligns itself between the Earth and Sun again.
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