The Moon's current synchroization with Earth? and How does Mercury's orbit compare to the Moon's?

Question

Describe the process that caused the Moon's orbit and rotation to achieve its current synchronization. (As the Moon orbits the Earth, it rotates once on its axis in exactly the same amount of time it takes to complete one orbit. Because of this synchronization of its orbital period and its rotation period, the Moon always keeps the same face pointed towards the Earth!!)

How does the orbit of Mercury around the Sun compare to the orbit of the Moon around the Earth? Does Mercury always keep the same face pointed at the Sun? Why or why not?

Answer 1

The moon and the earth are a "closely coupled" system. They are "coupled" by the force of gravity that they exert on one another, and the coupling is "close" because the earth and moon are relatively close in size (the earth is only four times larger) and close together.

The gravitational forces exchanged between large bodies are sometimes called "tidal forces". Earth's tidal force on the moon "stretches" it towards us, creating a tiny bulge around it's center. Until the moon is "locked" in its rotation (always facing the earth), this bulge will be pulled towards the earth and tend to pull the moon with it. This is called "tidal locking"

This does not occur for mercury, because mercury is much, much smaller than the sun, and is a relatively long distance away from it.