The full moon is one of the phases of the moon that occurs when the Earth, Sun and Moon are aligned, which means a brightness that can be seen in different parts of the world, but what happens when it is not?
The Moon, the Earth’s satellite, presents us with its various forms throughout the year, our feelings, with a moment of joy. However, it also depends on its relationship with the Earth, the forces of gravity, attraction and the Earth’s rotation to make its appearance in the night sky.
In fact, the Moon is a rocky object that does not have an atmosphere and does not emit light in the same way that it does not emit light, but when we look at the sky at night, we only see the part of the Moon that is being illuminated by the Sun at that moment. , but there are times when it is not seen.
Why do we see the full Moon?
It is said that when the moon is full, it is time to give birth. It is said that when the moon is full, it is to illuminate our lives. The universe gives us cyclical moments such as the seasons of the year, which are often related to the moon, although there is a specific one that lights up more than others: the full moon.
We know that the Moon revolves around the Earth. When we are at that moment of the spin in which the Sun, the Earth and the Moon are approximately aligned in that order, from the Earth we can see the entire illuminated side of the Moon and this is what we call “”.
The lunar cycle lasts approximately 29 days and 12 hours. This is the time necessary for the same lunar phase to repeat, or in other words, for the same relative position of the Sun, Earth and Moon to repeat. However, the time it takes for the Moon to complete one orbit around the Earth is somewhat shorter, approximately 27 days and 7 hours.
The difference between the two times is because while the Moon rotates around the Earth, the Earth is also rotating around the Sun. And The two cycles do not coincide exactly because the Earth moves, this is the main reason why sometimes we cannot see the full moon in the sky.
Let’s explain this in more detail:
Let us first assume that the Earth stops rotating on itself, but that the Moon continues to revolve around it. In this case, from a certain position on Earth we would see only half of the lunar cycle.
We would see how the Moon takes almost 14 days to cross the sky, changing phase in the process. If we saw it from the central point of the face always illuminated by the Sun (since that would happen in this imaginary case), we would see how it appears on the horizon in the last quarter, how it becomes shadowed as it approaches the position of the sun in the sky and how it lights up again until it reaches the crescent at the moment of hiding behind the horizon.
If we were in one of the areas where the Sun was always close to the horizon, we would see the Moon rise behind the horizon in the new moon phase and grow until the full moon on the other side of the sky.
If, on the other hand, we had the opposite situation, in which the Moon remains stationary in space but the Earth continues to rotate, then we would always see the same phase from when it rises to when it sets.
Depending on the point where we stop the Moon in this imagined experiment, we would see one phase or another. If we position it towards the sun, it will appear in the new moon phase and will barely be visible; if we place it at the point furthest from the Sun, it will always appear in the full moon phase. And at the intermediate points it will appear with a decreasing or increasing appearance.
With all this we see that the movement of the Moon around the Earth gives us the change in the lunar phases, while the rotation of the Earth itself causes us to see the Moon at different times of the day.
The offset between both movements causes the Moon to rise between 30 and 60 minutes later each day. This range actually arises from the fact that our satellite’s orbit is quite elliptical, so there will be times in the lunar cycle when it is ahead of the mean motion and times when it is slightly behind, and that is exactly when we cannot see the full moon in the sky.