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Crescent moon

  1. Oct 7, 2004 #1


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    is the shadow on a crescent moon the earth, or is it the dark side of the moon. i was taught in science a while ago that its the dark side of the moon, and an eclipse of the earth on the moon is something different and more rare. but what i dont get is, if we are seeing mostly the dark side of the moon, wouldnt that mean its in front of us, ie, closer to the sun? then how could we see it at night? i drew a simple picture to show what i mean. the lines from the earth to the moon represent what we would be able to see. so what am i missing?

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  3. Oct 7, 2004 #2


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    Imagine that you are someone standing on the night side of the Earth about where the gibbous moon lines meet. Now draw a line form this point to the crescent moon. Note that the Earth does not block your view of the crescent moon and that it will appear low near the horizon in your image. Add the fact that your image is not to scale, as the moon is more like 30 times the diameter of the Earth away, and the actual crescent moon will appear higher in the sky from that same vantage point.
  4. Oct 7, 2004 #3


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    A picture is worth a thousand words: http://www.virtualcivilization.org/moon.jpg [Broken]

    This picture shows the Sun, Earth, and Moon -- not to scale. The Earth rotates counterclockwise. The Moon revolves around the Earth counterclockwise, also.

    A person standing at location "A" on the Earth will be experiencing the beginning of night, about say 7 p.m. The Moon will appear directly overhead, and will not be entirely lit.

    The "dark side of the Moon" is indeed the part of the Moon not lit by sunlight. However, just like the "dark side of the Earth," that part of the Moon is always changing.

    - Warren
    Last edited by a moderator: May 1, 2017
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