Why is the Moon creeping away from Earth?

Conservation of angular momentum. The tidal forces that the moon causes on the Earth are gradually dissipating its orbital energy by friction and slowing its rotation (i.e. the day is getting longer). The total angular momentum of the Earth-Moon system has to be conserved. In order to compensate for the slowing of the Earth's rotation, the radius of the Moon's orbit has to increase.

Its not backward, its the law of conservation of momentum.

The moon raises tides on Earth, and the friction of the water against the land is slowing the Earth's rotation by about 2.3 ms/century. Momentum in a system is the result of all motions, and if the Earth's rotation is slowing, something has to change to make up the difference.

The only other motions in the system are the moon's rotation (which is locked by the Earth's tides on the moon) or its orbit, which can change.

Its called "tidal acceleration".

Lovely first answer, glad 7 people like it.

Unfortunately, the described effect - speeding up the moon would mean it would have to be closer because smaller orbits are faster.

In fact, both the earth's rotation and the moon's orbital velocity are changing and the moon is slowing and getting further away because of the transfer of energy. http://en.wikipedia.org/wiki/Tidal_acceleration

The Moon exerts a tidal force on the Earth, which creates a bulge. The Earth's rotation carries the bulge slightly forward of the Moon, so that the bulge's gravitational force on the Moon increases the Moon's forward velocity. As a result, the Moon orbits farther out, while the Earth's rotation slows.

nothing in the physical universe is stable and everlasting. This is a fundamental principle.

The Moon has ''no choice'' but to either move toward the Earth or away from it. This movement is caused by perturbations in the motions and gravitational fields affecting the two bodies. The Sun is also included in this interplay.

it is kind of like a magnet, you can move the magnet with more assuredness as it goes slower and slowly spirals outward. as there is less gravitational pull, it moves even farther out.

that or it just does not like us. but then, what do you expect from a ball of cheese?