The Lunar Phases


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Introduction
Lunar Phases are the different views we see of the moon due to the moon's rotation around the Earth. Even though the moon seems to "dissapear" and reapear again over the course of the month, it's really just the result of it's current position in the sky that allows us to see only part of the moon, or all or none of it, depending on where it is in it's rotation. There are also numerous myths, legends, and superstitions associated with the various phases of the moon.

Cause of Lunar Phases
The phases of the moon are the results of the angles of the moon, earth and sun when we view the moon. As the moon, earth, and sun rotate, we see more or less of the dark part of the moon. For example, during the new moon we see only the side that the sun is not currently illuminating, the dark side, and during the full moon we see only the side that is illuminated by the sun. This occurs because of the moon's rotation around the earth.

The Lunar Phases
The Lunar Phases

Types of Lunar Phases
There are five different named types of moon phases, but the crescent, gibbous, and quarter phases can be either waxing (transitioning from new moon to full moon) or waning (transitioning from full moon to new moon, making there really eight main phases in total. The phases are:
New moon- This is when the moon appears completely dark. We only see the "dark side" of the moon, meaning no visible moon is seen.
Full moon- A full moon occurs when the side of the moon we see is lit completely.The moon appears completely round and bright.
Quarter moon- A quarter moon is when the moon appears half lit. A quarter moon appears twice in the once, once during waxing and once during waning.
Gibbous moon- When the moon is between full and half full, it is called a Gibbous moon. A gibbous moon can be waxing or waning.
Crescent moon- This is when the moon is between half full and a new moon. Again, a crescent moon can be either waxing or waning.

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Rotation and Revolution
The time it takes for the moon to complete a full rotation on it's axis is roughly 27 days. Oddly enough, the time the moon takes to complete a full orbit, or revolution, around the Earth is also 27 days. Because of the two rotations taking almost the exact amount of time, we only see one side of the moon at all times, and never the other "far side". This isn't unique to our moon only. In our solar system, nearly all moons rotate at the same speed as their orbit. Our moon didn't always have the same rotation speeds, though. A long time ago, the moon used to spin faster. But the Earth's tidal pull on the moon slowed down it's rotation to match it's time going around the earth. This occurred because the Earth's gravitational force is stronger on the side closest to the Earth and weaker on the side further away. According to Astronomer James Hilton of the U.S Naval Observertory, the moon is slowing down the Earth's rotation as well. But this process, due the the moon's small size compared to the earth, will take "twice the age of the solar system", according to Hilton.

The Dark Side
The dark side of the moon is the part of the moon we cannot see currently due to the moon's position relative to the sun. When we see only part of the moon, for example a crescent moon, we're still looking at one complete side of the moon. The crescent that we see is just the only part of the moon that's illuminated by the sun at the time. A common misconception is confusing the "dark side" of the moon with the "far side" of the moon. As mentioned above, the dark side of the moon is just the part that is not currently lit up, and the far side is the side of the moon that we never see due to the moon's rotation.

Mythology
People have long been fascinated by the moon, and especially it's ever changing phases. Many ancient, and even modern, cultures have legends, myths and superstitions about the moon and/or it's phases. The full moon, especially, has attracted a wide collection of myths and superstitions for ages, with perhaps the most common being the legend of certain humans transforming into wolves under the full moon. The werewolf myths, though, aren't the only myths concerning the full moon. Many people are convinced that the full moon changes behavior, such as bringing up the suicidal rate or making people act as they normally wouldn't. Studies have shown that there is very little evidence for such behavioral changes, but many people are still convinced. The use of lunar phases is also common in horoscope telling.

Conclusion
In conclusion, the study of lunar phases is a very interesting one and I hoped you learned a lot about them from my wiki, such as why they occur, their different types and the myths and misconceptions concerning them.



Sources

http://library.thinkquest.org/29033/begin/phases.htm
http://www.moonconnection.com/moon_phases.phtml
http://csep10.phys.utk.edu/astr161/lect/time/moonorbit.html
http://skepdic.com/fullmoon.html
http://www.windows.ucar.edu/tour/link=/the_universe/uts/moon1.html&edu=elem
http://www.olliverlyle.com/Calendar/images/moonorbit.gif
http://www.ncbi.nlm.nih.gov/pubmed/16393713
http://www.enchantedlearning.com/subjects/astronomy/moon/Phases.shtml
http://www.air-and-space.com/Moon%20200408.htm
http://www.grantchronicles.com/astro29.htm
http://www.wonderquest.com/MoonSpin.htm
http://www.badastronomy.com/bad/misc/dark_side.html