Lunar Cycles

As the shape of the Moon changes periodically, most of us wonder why it happens. Here, you will get a brief overview about the phenomena of lunar cycles. Read on to learn more...
UniverSavvy Staff
Last Updated: Jun 5, 2018
Moon in Different Phases Against Black Sky
Mankind has been closely observing the different stages of lunar cycles since time immemorial. The beauty of full moon on a clear sky captivated the imagination of so many poets.
We all were fascinated with the Moon in our childhood days simply because it looks so different every night. It grows from a thin crescent curve to a round-shaped disk. The actual cause behind the ever-changing appearances of the Moon is the lunar cycle.
Basic Facts about Lunar Cycles
Penumbral solar eclipse cycle with black background
We all know that the Moon is the satellite of the planet Earth and it revolves around the Earth in an elliptical path. It takes approximately 29.5 days to complete one lunar cycle. This period is also known as lunation.
One half of the Moon that faces the Sun remains lit by sunlight all the time. The other half of the Moon which is away from the Sun is dark. As the Moon moves on the elliptical shaped orbit, the angular distance between the Moon and the Earth changes from time to time.
Moreover, the Earth is also rotating around the Sun in its oval-shaped orbit. Thus the angular position of the Moon and the Earth is changing constantly. These changing angles brings about changes in the appearances of the Moon.
Main Phases of Lunar Cycle
Moon phases, elements of this image are provided by NASA
There are eight different phases of a lunar cycle or lunation. In each phase, the alignment of the Sun, Moon and Earth in the sky changes.
New Moon
New Moon
During the new moon phase, the Sun, Moon, and Earth are all lined up in one straight line. The Moon is placed in between the Earth and the Sun. As a result, the illuminated portion of the Moon becomes completely invisible to an observer standing on the Earth.
Waxing Crescent
The Moon starts drifting from the new moon phase towards the full moon phase. During this phase, the size of the illumined portion of the Moon is increasing and less than fifty percent of the Moon is visible to us. You can see the waxing crescent moon between sunset and midnight.
The First Quarter
Half moon
Here, the Moon is positioned perpendicular with respect to both the Sun and the Earth. In this phase, right half portion of the Moon is illumined by sunlight and is visible in between afternoon and early part of the night.
Waxing Gibbous
waxing gibbous moon on cloudy sky
The duration of this phase is of seven days. Here, more than fifty percent of the Moon is illuminated from right to left. This appears just after sunset and is visible almost throughout the night.
Full Moon
Moon on Cloudy day
During the full moon, the Sun, Moon and Earth are aligned in a straight line and the Earth lies in between the Moon and the Sun. Thus the entire illuminated portion of the Moon is visible to us.
Waning Gibbous
reducing moon
This can be described as a phase where the visible portion of the Moon is shrinking to a smaller size. Still, more than fifty percent of it can be viewed from the Earth.
During this period, the Moon is lit from left to right. This Moon can be seen by joggers and morning walkers early in the morning as it sets after sunrise.
The Third Quarter
This is phase when the illumined portion of the Moon reduces to half of its size in the full moon phase. Here, the right half of the Moon remains unilluminated. You can see it late at night or early in the morning.
Waning Crescent
This is an interesting phase as the Moon is getting smaller and you can see only a thin slice of the Moon and that too, not after midnight.
New Moon
The Moon starts a new journey all over again. This is often referred to as dark moon as the Moon is not visible at all.
Researchers and scientists believe that lunar cycles affect sea tides and may cause some climatic changes as well. Apart from the scientific observations, lunar cycles are also closely watched by astrologers. They think that lunar cycles have strong influences on the way men and women react to a certain situation at a given point of time.