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The Phases of the Moon:





The Moon, Like the Earth and all the other planets, is visible to us only because it reflects Sunlight.  In the Moon's case it's not a lot (~3%).

Since the Moon orbits the Earth, its position relative to us and the Sun determines how much of its illuminated surface we see.  This changing pattern is what we mean by phases.
 
 






It's actually pretty easy to figure out how the Moon should look from the Earth for a given position in its orbit.

       A        B       C            D             E           F       G
 

New moon
A) Waxing crescent
B) Waxing quarter
C) Waxing gibbous
D) Full
E) Waning gibbous
F) Waning quarter
G) Waning crescent
New moon

Click here for movie or check out Lunrphs.mov on your Textbook CD ROM

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