Similarly, the moon’s gravitational force affects oceans causing low and high tides, while the earth, which is bigger than the moon, causes low and high gravitational pull on it. Additionally, as the moon rotates around the earth in its orbit, the earth exerts a torque on the rotating system of the moon. This causes the moon’s speed along its own axis to slow down, eventually revealing only one side of the moon as it completes its rotation (Pandian).
The moon is also viewed as though facing only one side of it on earth through a concept known as libration, which occurs because of the spherical nature of the moon. Libration is the irregular motion of the moon in its orbit computed longitudinally and latitudinally from a fixed geographical location on the moon’s surface (Coffey).
The earth affects the moon through its elliptical orbit, a process called longitudinal libration. This implies that when the moon is nearer the earth in its orbit, the earth’s gravitational pull is stronger. This makes the moon move faster on its axis, but since the moon’s rotational speed is constant, it causes a lag or a pull effect (Coffey). This pull effect on the moon’s surface causes the earth to view an extra portion of the moon’s surface up to 59% of it. When the moon orbit is farther away from the earth, the earth’s gravitational force on it is weak, causing it to slow down, even though its rotational speed remains the same. This makes the moon “spin” away from the earth and, as a result, it becomes only 41% visible (Miles).
In addition, we view one side of the moon surface because of latitudinal libration caused because the moon’s orbit is tilted 5 degrees towards the ecliptic. Therefore, during the moon’s rotations around the earth, half of it is on the higher side while the rest of the revolution is on the lower side. This causes an extra part of the moon to be ...Show more