Why is the moon turned to the Earth by one side? The Unseen Side of the Moon

The moon is a natural satellite of the Earth. Mysterious and beautiful, it has attracted the eyes of astronomers since ancient times. Even then, many of its features were noticed: the phase changes, the time of sunrise and sunset, the duration of the lunar month. Noticed by ancient scientists and the permanence of the face of the night luminary. True, in those days they did not ask themselves why the moon was turned towards the Earth by one side. For them, this was the only possible position, fully consistent with the prevailing beliefs about the structure of the sky.

Today things are somewhat different. Our ideas about the motion and interaction of cosmic objects, supported by numerous observations, are very different from those that existed in ancient times. And practically everyone from the school bench knows why the Moon is turned towards the Earth by one side.

The beginning of history

To date, one of the secrets that Luna stubbornly does not want us to discover is her origin. Various studies conducted to obtain a definitive answer to this question have so far produced several versions. According to one of them, the Moon and the Earth are sisters formed approximately at the same time from a common protoplanetary cloud. This is supported by the results of radioisotope analysis, which made it possible to determine the same age of two cosmic bodies. However, there are also data, which testify to the great differences in the composition of our planet and its satellite. The version is put forward to them: The moon was formed somewhere far in space and, having approached the Earth, it was captured by it. A hypothesis is also close to it, suggesting that several cosmic objects were attracted, which after a while collided and formed the Moon. Finally, there is also a theory that our planet is more like a mother to her companion: The moon appeared as a result of a collision of the Earth with a huge body. The beaten part began to rotate in orbit around the "ancestor".

The "satellite-planet" system

Whatever it was, it is for certain only known that the Moon is a natural satellite of the Earth. According to astronomical data, the night light at the time of its formation was located much closer to our planet. Moreover, it quickly flew around the Earth and turned one or the other side. This situation is typical for the initial stage of the evolution of the satellite-planet system. An example of the outcome of such "relationships" is Pluto and his accompanying Charon. Both cosmic bodies are always rotated to one another by one side, their rotation is synchronized. But first things first.

Tidal acceleration

Young Moon immediately began to affect the Earth. This was expressed in the formation of tidal waves in newly emerged oceans, as well as in the crust. This effect has two main consequences. First, as a result of certain features of the structure of the Earth and its rotation, the tidal wave precedes the Moon. The entire mass of our planet, enclosed in such waves, in turn, affects the satellite, gives it acceleration, and the Moon starts moving faster, gradually moving away from the Earth. Secondly, in this process there is also an oppositely directed force that inhibits the movement of continents. As a result, the speed of the Earth's rotation around the axis decreases, and the length of the day increases.

The moon moves away from our planet by about 4 cm per year. However, this is not an eternal process, and the probability of losing its satellite to the Earth is negligible. The "escape" of the Moon will end at the moment when the Earth's rotation around the axis is synchronized with the satellite's orbital motion. In this case our planet will always look at the night star with the same side.

A similar process

It is easy to assume that the answer to the question of why the Moon is turned towards the Earth by one side is connected with a similar phenomenon. Indeed, the gravitational force of the Earth causes similar tidal waves in the bowels of the satellite. Because our planet is more massive, the force of its impact is much more palpable. Obeying it, the Moon has long synchronized its rotation with the motion around the Earth. As a result, always available for observation and the invisible side of the moon.

Slightly more than half

An attentive amateur astronomer can quickly find out that the face of the night light does change somewhat. The visible side of the moon does not occupy exactly half of it. The orbit of the night light deviates from the plane of Earth's rotation around the Sun (the ecliptic) by about 5 degrees. In addition, at 1.5º relative to the trajectory of the moon's movement its axis is shifted. As a result, observations are available up to 6.5º above and below the poles of the satellite. This process is called lunar latitude latitude. Similarly, the longitude of the satellite oscillates. The change in the speed of the Moon's movement as a function of the distance to the Earth leads to it. The hidden part of the satellite due to this is shortened, and the other side of the moon, illuminated, increases to 7º longitude. So it turns out that in total you can observe up to 59% of the lunar surface.

In the distant future

So, the question of why the Moon always looks at the Earth with one side finds the answer in the peculiarities of the effect of the gravitational force of the planet on the satellite. However, as it was said, a similar process after a certain time will lead to the fact that the Earth will look at the night light with only one part of it, regardless of the phase of the Moon. According to John Darwin, grandson of the founder of the theory of evolution, the duration of the day by this time will be equal to fifty days familiar to us. The distance dividing the Earth and the Moon will increase by about one and a half times. This will be the most ideal state of the satellite-planet system.

Solar tides

There is, however, some probability that the Moon is never destined to achieve sufficient removal. The reason for this possibility lies in the solar tides. The daylight has a similar lunar impact on both the planet and the satellite. If this fact is included in the theoretical construction of the future two cosmic bodies, it turns out that at a certain distance from the Earth the Moon will again come closer. This reduction in distance will have devastating consequences. When the Moon is at a distance of 2.9 radii of the Earth, it will be torn apart by forces of attraction.

Another "but"

However, this picture can not be realized. The fact is that according to forecasts, the removal of the moon, then its approach and, finally, the death will take several trillion years. During this time, a catastrophe can occur on a more serious scale, at least for all life on the planet. The sun will be extinguished, which has exhausted all the reserves of stellar fuel. After this, all the conditions of interaction in the planetary system of the luminary will change.

Study

The other side of the Moon, inaccessible to direct observation, for a long time was a mystery, literally covered in darkness. Only the beginning of the space age gave the opportunity to get to know her better. The first aircraft, which photographed about 70% of the surface of the hidden part, was the Soviet "Luna-3". Pictures taken to Earth showed that the relief of the reverse side is somewhat different from the nature of the visible surface. There were practically no plains of the seas. It was found only two such formations, later called the Sea of Moscow and the Sea of Dreams.

The Giant Crater

In 1965, the space probe "Zond-3" went to the Moon. He completed the survey of the invisible part of the satellite. The image of the remaining 30% of the surface only confirmed the conclusions drawn earlier: the surface in this part is covered with craters and mountains, but there are practically no seas on it.

The most impressive size is one of the craters, located exactly on the dark side of the moon. Its length is 2250 km, and the depth is 12 km.

Hypotheses

Today, the secrets of the reverse side of the Moon are in many ways solved. However, the human mind is prone to fantasize about those things and phenomena that are inaccessible to immediate observation. Therefore, on the Internet, it is easy to meet the most bizarre hypotheses that have to do with the whole of the Moon as a whole or only its hidden side. There are assumptions about the artificial origin of the satellite, its population of extraterrestrial intelligence and the deliberate concealment of one of the parties. There are also references to the mysterious space base located on the dark part of the satellite. Similar versions are difficult to confirm and disprove. No matter how truthful or false they are, they are based on the same reason that prompted people to conquer outer space: the hope to find in the boundless expanse of the universe of fellow human beings the desire to touch the unknown.

However, today it is quite precisely known why the Moon is turned towards the Earth by one side. And the assumption of an artificial origin has not received any serious continuation. The answer to this question has become as obvious as understanding, in which phase the Moon is today and why. We can not, however, say that we know everything about the earthly satellite and that no discoveries are expected in the future. On the contrary, the night light to match the ancient deities personifying him remains mysterious and does not hasten to share secrets. Mankind has yet to learn a lot of interesting information about the satellite of our planet. Perhaps the new stage of the study, which began just recently, will bear fruit in the near future. It is absolutely certain that the realization of some NASA projects is of great importance in this respect. Among them is "Avatar", which consists in developing a telepresence suit. He will, while on Earth, using robots to conduct experiments on the Moon. Huge hopes are placed on the project of colonization, the implementation of which will result in the deployment of a scientific base on the satellite of our planet.