19 June 2014
The Short Answer (TSA)
Most have heard of the “Crescent Moon,” and most of us know what
a crescent shape looks like. But a “Gibbous Moon” doesn't ring any familiar
bells. The Moon is “Gibbous” when more than half, but less that all, of the
Moon’s face is sunlit.
The Moon’s phases begin with the "New Moon" -- when the Moon
disappears and can’t be seen in the night sky.
When the Moon “returns,” it first appears as a “Crescent Moon” with the smallest
sliver of light on its face. The light
on the Moon’s face increases until it reaches the “1st Quarter” phase when half
the Moon’s face is sunlit.
But, before we go any father, we need to clear up some
confusion of about the “quarter” Moons. At the phases called the “1st Quarter”
and the “3rd Quarter,” exactly half of the Moon’s face is sunlit. So, if half the Moon is light, why is it
called a “quarter?”
The word “quarter” refers to time instead of to the light on
the Moon’s face. So, the “1st Quarter” is one fourth (1/4th) of the way through the time
(29.6 days) it takes to complete a full cycle of the Moon’s phases: from the
New Moon to the next New Moon.
After the “1st Quarter Moon,” the Moon is called “Gibbous.”
Again, this means that more than half, but less than all, of the Moon’s face is
sunlit. There are two “Gibbous Moons” in each cycle of the Moon’s phases.
The first is called the “Waxing Gibbous Moon.” “Waxing” means increasing. So,
the “Waxing Gibbous Moon” is the phase between the “1st Quarter Moon” and the “Full
Moon,” when the sunlit part of the Moon’s face is increasing in size.
There will be another Gibbous Moon. But the next one will be called a “Waning
Gibbous Moon.” “Waning” means
decreasing. The whole face of the Moon
is sunlit at the Full Moon but, then, the sunlit part of the Moon’s face begins
to decrease in size.
Just after the Full Moon, we have another Gibbous Moon
because, again, more than half, but less than all, of the Moon’s face is
sunlit. But the sunlit part of the
Moon’s face will continue to decrease.
So this is a “Waning Gibbous Moon.”
The “Gibbous” phase will end when only half of the Moon’s face is
sunlit, the “3rd Quarter Moon.”
M Grossmann of Hazelwood, Missouri
(& Belleville, Illinois)
About the Author
19 June 2014
M Grossmann of Hazelwood, Missouri
(& Belleville, Illinois)
About the Author
19 June 2014
No comments:
Post a Comment