eli5: If I’m in the Southern hemisphere and I see the full moon, will someone in the Northern hemisphere see it too?

Question

eli5: If I’m in the Southern hemisphere and I see the full moon, will someone in the Northern hemisphere see it too?

In: Earth Science

Answer 1

Yes, or at least mostly yes.

The moon’s orbit is relatively aligned with the Earth’s so it’s typically visible from anywhere on Earth each day for the same reason that daylight is. Since the phase of the moon is determined by the sun-moon-earth angle – which doesn’t really depend meaningfully on the observer – you will generally speaking both be able to see the full moon.

Now, if you are very close to the poles, it is *possible* that the moon will be above the horizon for one of you and not the other, even if it’s nighttime for you both. But if the moon is south of the sun in the sky, it’s possible for (a) it to be nighttime close to both poles, (b) the moon to be visible for one pole, and (c) the moon to be below the horizon for the other. But this can only happen very close to the poles, where no one really lives.