The Moons Phases

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The Moon's Phases

This animation shows the Moon at eight positions on its orbit, along with a picture of what the Moon looks like at each position as seen from Earth. At any time, half of the Moon (one hemisphere) is illuminated by the Sun. As the Moon orbits the Earth, we see varying amounts of the illuminated half of the Moon (shown as yellow in this animation).

[flash width=480 height=304 loop=true]misc/flash/astronomy/moonphase.swf[/flash]

SOURCE: Freedman and Kaufmann, Universe, Seventh Edition, W. H. Freeman & Co.
http://www.whfreeman.com/astronomy/