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View from the Earth-Moon L5 point?

  1. Oct 25, 2008 #1
    Hey folks,

    Can anyone tell me how the Earth and Moon would appear to an observer at the Earth-Moon L5 point? I'm guessing both the Earth and Moon would appear to be in the same "phase", but would they be close together? How fast would they change position relative to each other? And what would their apparent relative sizes be?

    Thanks for any info!

    Chris B
  2. jcsd
  3. Oct 25, 2008 #2

    D H

    Staff: Mentor

    The Earth, Moon, and L5 point (or Earth, Moon, and L4 point) form an equilateral triangle. The Earth and Moon would appear to be separated by 60 degrees, and they would be 60 degrees out of phase.
  4. Oct 26, 2008 #3
    Okay, thanks, I see what you mean about the phase. And now that I think about it, I guess they would not move in relation to each other at all, but stay in exactly the same relative positions. And since it's an equilateral triangle, the Earth and the Moon would be equidistant from the observer, so the Moon's diameter should appear a quarter of the Earth's diameter, as it actually is.

    Thanks again.
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