It appears to me that the Moon has appeared in many locations - evident locations - in the "dome that the sky". I know that the Sun follows an arc from eastern to west and that the arc is smaller in winter 보다 in summer. Thus the sunlight cannot show up in every ar in the "dome that the sky".My question is: can the moon show up in any (every?) place in the "dome of the sky"?


Like the sun, the moon, indigenous our view on the surface of the Earth, rises in the East and also sets in the West. However, it does not rise precisely due east and set exactly early West. If you to be to monitor the position of the moonrise along the horizon over the course of a year, friend would notice that is different considerably. It cannot, however, be located anywhere in the night sky, also over the food of a year.

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To know why, we require to understand some celestial geometry.


The ecliptic plane is the airplane which a theoretical line in between the Earth and also the sun sweeps out over the food of a year. In the image above, you can see exactly how the Earth"s orbit exist within this plane.

Also notification that the line from the Earth"s geographical south pole through its phibìc pole (its rotational axis) is no perpendicular come this ecliptic plane. In fact it is 23.5 degrees off this perpendicular direction.

Notice that the Earth"s rotational axis points in the exact same direction nevertheless of which next of the sun the planet is right now on. This rotational axis always points towards the star Polaris. This way that on different parts the the year, the sun will rise at differing points follow me the horizon.

The Earth"s equatorial airplane is a plane defined to expand out native the Earth"s equator in all directions. This plane is inclined family member to the ecliptic aircraft by 23.5 levels (the very same amount together the rotational axis is tilted loved one to the perpendicular direction that the ecliptic plane).


Now consider the earth moon system. In order to identify how far North or southern the moon can show up to rise from, you need to think about the angle in between the Earth"s equatorial plane and the moon"s orbital plane. Because the Earth"s rotational axis is inclined 23.5 levels relative to the ecliptic, and also the Moon"s orbit is lean 5.14 degrees relative come the ecliptic, the highest possible the Moon"s orbit can be loved one to the equatorial aircraft of the earth is 28.64 degrees.

Thus, the Moon can not be directly overhead the any point on the surface of the planet if that allude is 28.64 degrees above or (by an symmetric argument) listed below the equator.

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Thus, the Moon cannot appear in every ar in the sky for a provided location on Earth. There are parts of the skies that the geometry that the planet moon device simply will not allow the Moon come exist.