Why can we sometimes see the moon during the day?

  • At some points in the year, the moon at my location can be clearly visible during the day. Why is this?

    If it is any help, I live in Alberta, Canada.

    It's a common misconception that the appearance of the moon in the sky is mostly a nighttime phenomenon. Most people are familiar with the Bible verse "God made two great lights—the greater light to govern the day and the lesser light to govern the night." (Genesis 1:16) But the fact is over the course of each month, the moon spends just as much time in daytime sky as it does in the night sky. You're just less likely to notice the moon during the day.

    @David H I guess this question should more appropriately be worded, why can I see the moon on some days but not on others

    You can see the moon at some times and not at others, for the same reason you can see the sun at some times and not at others. There's a big object called "Earth" between you and what you are looking at.

  • Envite

    Envite Correct answer

    9 years ago

    The Moon makes a full orbit around the Earth once per month. From full moon to full moon, it is 29.53058886 days (synodic month).

    Full moon happens when the Moon is at one side of the Earth (right side in the image), and the Sun is at the other side. This way, Moon is fully iluminated by Sun (except in the cases where it is exactly in the opposite side of the same line, where you have a Moon eclipse). In this phase, Moon is at its highest altitude at midnight.

    Then, as the Moon orbits, it comes closer to the Sun in the sky. This means both that it shows us less iluminated percentage and that its rise and set get delayed. At Last Quarter, Moon is at its highest altitude at sunrise. This means that you will be able to see the half moon figure on the sky during the morning (and last half of the night).

    enter image description here

    Then it comes New Moon, where the Moon is nearest to the Sun in the sky, and almost invisible, since it shows us the dark side during the day. Its highest altitude is at noon, but you will not be able to see it. You can, if you are lucky, see a Sun Eclipse.

    Finally it comes First Quarter. To put it short, highest altitude is at sunset and you are able to see Moon during all the afternoon (and first half of the night).

    Moon rises roughly at sunset on the day that it's full, and every night thereafter rises 52.7 minutes later than the previous day. The moon is above the horizon a bit less than half the day, every day of the month. However, it can be impossible to see during the day during its first and last phases, when it's quite near the sun.

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Content dated before 7/24/2021 11:53 AM

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