In fact, you can see more than half of the moon

Although the Earth is usually seen only one constantly converted to our half moon, sometimes we can "see" the invisible side on her right and left, taking about 5% of each "side". The fact that the moon periodically like "ranges". These movements are called libration.

First libration is due to the fact that the moon is inclined with respect to the solar light so that its north pole is located at a short distance from the sun for two weeks and the following two weeks, on the contrary, is inclined to it. Thus, in the first two weeks of the month we can see one half of the north pole of the moon, and in the second two weeks - another.

There are also daily libration. Earth much more of the moon, so the moon can be seen rising from one side of the horizon and sunset - on the other. If you stand in the right place, you can watch the moon on two opposite sides for one night. This will allow you to see the small extra pieces on each side of the moon.

Finally, the moon revolves around the Earth in its orbit with changeable speed, but its route - not a circle but an ellipse. A rotation of the satellite about its axis occurs at an almost constant speed. As a result, the visible earthly observer rotation of the Moon is uneven, and we can turn a little "look" to turn away from the Earth's brain turns to the east and the western edge.

via factroom.ru