Posts Tagged ‘phases’

PostHeaderIcon The Full Moon

So there was an old mystery novel that set up the chilling night time scene with:

The big full moon rose over the horizon just at midnight.

Did anything strike you funny about this particular scene? Have you ever wondered why sometimes you see the moon during the day? Well, depending on what phase the moon is in you can figure out roughly when the moon rose and when it will set during any part of the day.

Moon Phases

The Phases of Our Moon

It takes the Moon roughly 29 days to make a complete rotation around our planet and the above chart show the placement of the eight major phases the Moon takes and where it lies in orbit at that time. The detailed Moon phases show what we get to see from Earth at the time the Moon is in the location designated by the simple white and gray circle.

As the Earth sits in the picture remember that the spot closest to the sun would be Noon and the spot further away, in the dark, would be Midnight. From anywhere along the Earth you can put yourself and draw a straight line from that point to the Moon phase you want to see and that’s where it would show up at that time. (Provided the Earth doesn’t get in the way.) Say we’re at the top of the Earth, where the light and dark side meet, this is “sunrise” so if we drew a line straight up (looking straight up into the sky) we would see a half-moon. However, what if it was sunrise but we wanted to see the full moon? Well, if we drew a line to it, the Earth’s horizon would just touch that line. If we rotation anymore into the morning, the Earth would block our site. Therefore, if we looked for a Full Moon at sunrise it would have to be just setting over the horizon. If we stood on the other side at “sunset”, the opposite Full Moon would be right over head, and the Full Moon would be just coming into view over the horizon.

What about the New Moon? Well, since we’re looking at the dark side of the moon during that phase, no real light is bouncing off to show itself to us. However, the best time to see a New Moon is, of course, during a Solar Eclipse, when the Moon steps right out in front of the Sun and blocks its light temporarily.

So next time someone’s alibi includes the Full Moon rising at midnight, you’ll know something’s up.

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