The Moo5 - to go from one major phase to the next - by...

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The Moon After figuring out how the stars and the Sun move, it is time to tackle the next object - the Moon. The motion of the Moon is more complex; it doesn't follow exactly the ecliptic or the celestial equator, but does make a path around the Earth that is similar to each of those paths. What sets the Moon apart from the other objects is the fact that its appearance changes - it goes through phases. The phases of the Moon take 29.5 days to go through an entire cycle. The phases occur in a very predictable sequence. Here is the order of the phases - New (when you can't see the Moon - it's all dark), Waxing Crescent, First Quarter (when you see the right half lit), Waxing Gibbous, Full (when you see the entire lit surface), Waning Gibbous, Third Quarter - also called Last Quarter (when you see the left side lit up), Waning Crescent, and back to where we started, New. A picture of the phases is shown in Figure 7. It takes about one week
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Unformatted text preview: to go from one major phase to the next - by major phase I mean New, the Quarters and Full. If the Moon is New today, it will be a First Quarter Moon in about one week, and a full Moon two weeks from today. The fact that it takes about 29.5 days to go through the cycle is the reason there are about 30 days in a month, since many ancient societies used the Moon as a time keeper. Figure 7. The phases of the Moon as seen from Iowa when the Moon is high in the sky (on your meridian). What causes the phases? To figure that out, you need to look at the interaction of the light source (Sun) and the alignment of the Moon with the Earth. The Moon will have a certain phase depending upon two things -1. The location of the Moon in its orbit about the Earth 2. The location of the Sun relative to the Earth and the Moon at that time Don't forget about these two things....
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This note was uploaded on 12/15/2011 for the course AST AST1002 taught by Professor Emilyhoward during the Fall '10 term at Broward College.

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