Everyone knows that the Moon never turns its other side to us. This is due to the fact that its rotation around the Earth coincides with the rotation around its axis. It is easy to assume that being on Earth, the observer is able to see only one half of it. However, in reality, this is not entirely true. We can look at its dark side.
The fact is that the rotation of the Moon around the Earth is uneven, the Moon rotates at different angular speeds at perigee and apogee. In the first case, it rotates faster, in the second – slower. At the same time, the speed of its rotation around the axis is constant. This leads to the fact that the moon in the night sky fluctuates slightly or sways.
As a result of this, while on Earth, we can observe part of the western and part of the eastern side of the moon, which is always hidden from us. In addition, due to the peculiarity of the location of the axis of the moon, namely, that it is slightly inclined to the plane of its orbit, we can also see the north and south of the dark side.
These four, sometimes visible parts of the moon in science are called lunar libration zones, respectively, in longitude (east and west) and in latitude (north and south). In total, they give us an additional 9% of the surface of the moon. Thus, from the Earth, we see not 50% of the surface of our satellite, but 59%.
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At first glance, the invisible territory of the Moon was shot in detail, however, observing it yourself is not such a simple task. If you buy a telescope or binoculars and try hard, you can see areas that not many amateur astronomers have been able to observe.