Is there some well known reason that moons have synchronous rotation?

Question

A synchronous rotation is when the moon or other such object has the same face towards the object which it is a moon of or which it is rotating around.

Our moon is a good example in that as the moon rotates around the Earth it rotates on its axxis in such a way that the same face of the moon faces the Earth. ( I know that there is a extremely slight difference BUT we see basically the same side of the moon )

I rrecently read that most moons have this same property in that the same face of the moon faces the planet or other object which it rotates around.

Is there some well know reason for this and what is it called (if it has a special name ) and or what would I search for other than synchronous rotation

Answer 1

The rotation of a planet or satellite whose period is equal to its orbital period. Hell most of our moons in this solar system have this because of tidal locking.

Tidal locking makes one side of an astronomical body always face another, as the Moon faces the Earth. A tidally locked body takes just as long to rotate around its own axis as it does to revolve around its partner. This synchronous rotation causes one hemisphere constantly to face the partner body. Usually, only the satellite becomes tidally locked around the larger planet, but if the difference in mass between the two bodies and their physical separation is small both may become tidally locked to the other, as is the case between Pluto and Charon.

Rotation-Orbit resonance: Finally, in some cases where the orbit is eccentric and the tidal effect is relatively weak, the smaller body may end up in an orbital resonance, rather than tidally locked. Here the ratio of rotation period to orbital period is some well-defined fraction different from 1:1. A well known case is the rotation of Mercury—locked to its orbit around the Sun in a 3:2 resonance.

Answer 2

The Moon orbits the Earth. It is made of rock. It has no strong magnetic field and it has an atmosphere which is thought to weigh about 10,000 tons. When spread around, the atmosphere is all but non-existent. None of the surface rocks contain any water, not even as water of crystallisation. Apart from that, the rocks are the same kind as on Earth. The Moon is getting further from the Earth all the time at the rare of a few centimetres per year. There is a lot more on Wikipedia if you look there.

Answer 3

Regardless of the all of theoretical explanations I think I'll just add that many of these moons are essentially eccentric or egg shaped. This would make the largest part of it's body or core offset.& in so saying it only seems logical they would "lock" that way. Think of it as a hard boiled egg than.More than likely these moons would have a solid core verses a "chewy" molten center.

Answer 4

Mmm.. Chewy Molten Satelite Centers. o.o

Answer 5

Gravity?

Answer 6

The phrase that you are looking for is "tidal locking" See

http://en.wikipedia.org/wiki/Tidal_locking