Why is the dark side of the moon invisible? Earth - Moon: what is the future? What kind of hidden moon are you

During the movement of the earth satellite along its orbit in the first quarter of the lunar cycle, the apparent distance of the Moon from the Sun begins to develop. A week after the onset of the new moon, the distance from the Moon to the Sun becomes exactly the same as the distance from the Sun to the Earth. At such a moment, a quarter of the lunar disk becomes visible. Further, the distance between the Sun and the satellite continues to grow, which is called the second quarter of the lunar cycle. At this point, the Moon is at its farthest point in its orbit from the Sun. Her phase at this point will be called the full moon.

In the third quarter of the lunar cycle, the satellite begins its reverse movement relative to the Sun, approaching it. again reduced to the size of a quarter of the disk. The lunar cycle ends with the satellite returning to its original position between the Sun and the Earth. At this moment, the consecrated part of the Moon completely ceases to be visible to the inhabitants.

In the first part of its cycle, the Moon appears above the horizon, along with the rising Sun, is at its zenith by noon and in the visible zone throughout the day until sunset. Such a picture is usually observed in and.

Thus, each appearance of the lunar disk depends on the phase in which the celestial body is at one time or another. In this regard, such concepts as the growing moon, as well as the blue moon, appeared.

Man is drawn to the unknown, the mysterious, the unknown. One of these mysteries can be considered the far side of the moon. A unique phenomenon in the solar system - an earthly observer sees only one and at a certain time a "piece" of the other side of the only natural satellite of the Earth.

Instruction

The phenomenon, which many consider mysterious (only one lunar hemisphere is visible from Earth), is quite understandable. This is due to the synchronization of the earth and lunar period of revolution. Perhaps the Moon once revolved around the Earth differently. But as a result of the interaction over millions of years, the earth's gravity had a significant impact on the period of revolution of its satellite. Thus it turned out that the Moon makes a full revolution around its axis in the same time as around the Earth.

Why doesn't the moon rotate and we only see one side? June 18th, 2018

As many have already noticed, the Moon is always turned to the Earth by the same side. The question arises: relative to each other, is the rotation around their axes of these celestial bodies synchronous?

Although the Moon rotates around its axis, it always faces the Earth with the same side, that is, the rotation of the Moon around the Earth and rotation around its own axis are synchronized. This synchronization is caused by the friction of the tides that the Earth produced in the shell of the Moon.

Another mystery: does the moon rotate on its axis at all? The answer to this question lies in resolving the semantic problem: who is at the forefront - an observer located on Earth (in this case, the Moon does not rotate around its axis), or an observer located in extraterrestrial space (then the only satellite of our planet rotates around its own axis). axes).

Let's conduct such a simple experiment: draw two circles of the same radius that are in contact with each other. Now imagine them as discs and mentally roll one disc around the edge of the other. In this case, the rims of the discs must be in continuous contact. So, how many times, in your opinion, will a rolling disk turn around its axis, making a complete revolution around a static disk. Most would say once. To test this assumption, let's take two coins of the same size and repeat the experiment in practice. And what is the result? A rolling coin has time to turn twice on its axis before making one revolution around a stationary coin! Surprised?

On the other hand, does a rolling coin rotate? The answer to this question, as in the case of the Earth and the Moon, depends on the frame of reference of the observer. Relative to the initial point of contact with a static coin, the moving coin makes one revolution. Relative to an outside observer, in one revolution around a fixed coin, a rolling coin rotates twice.

Following the publication of this coin problem in Scientific American in 1867, the editors were literally inundated with letters from indignant readers who held the opposite opinion. They almost immediately drew a parallel between the paradoxes with coins and celestial bodies (the Earth and the Moon). Those who held the view that a moving coin has time to turn around its own axis in one revolution around a stationary coin were inclined to think about the inability of the Moon to rotate around its own axis. The activity of readers regarding this problem has increased so much that in April 1868 it was announced that the controversy on this topic in the pages of Scientific American had ceased. It was decided to continue the debate in a magazine dedicated specifically to this "great" problem, The Wheel ("Wheel"). At least one issue is out. In addition to illustrations, it contained a variety of drawings and diagrams of intricate devices created by readers in order to convince the editors of their wrong.

Various effects generated by the rotation of celestial bodies can be detected using devices like the Foucault pendulum. If it is placed on the moon, it turns out that the moon, rotating around the earth, makes revolutions around its own axis.

Can these physical considerations act as an argument confirming the rotation of the Moon around its axis, regardless of the observer's frame of reference? Oddly enough, but from the point of view of general relativity, probably not. We can generally assume that the Moon does not rotate at all, it is the Universe that rotates around it, creating gravitational fields like the Moon rotating in a stationary space. Of course, it is more convenient to take the Universe as a fixed frame of reference. However, if you think objectively, with regards to the theory of relativity, the question of whether this or that object really rotates or rests is generally meaningless. Only relative motion can be "real".
To illustrate, imagine that the Earth and the Moon are connected by a bar. The bar is fixed on both sides rigidly in one place. This is a situation of mutual synchronization - and one side of the Moon is visible from the Earth, and one side of the Earth is visible from the Moon. But we do not, so Pluto and Charon rotate. And we have a situation - one end is fixed rigidly on the Moon, and the other moves along the surface of the Earth. Thus, one side of the Moon is visible from the Earth, and different sides of the Earth are visible from the Moon.

Instead of a barbell, the force of attraction acts. And its "rigid mount" causes tidal phenomena in the body, which gradually either slow down or speed up the rotation (depending on whether the satellite rotates too fast or too slowly).

Some other bodies in the solar system are also already in such synchronization.

Thanks to photography, we can still see more than half of the surface of the moon, not 50% - one side, but 59%. There is a phenomenon of libration - the apparent oscillatory movements of the Moon. They are caused by irregular orbits (not perfect circles), tilts of the axis of rotation, tidal forces.

The Moon is in tidal lock on the Earth. Tidal capture is a situation when the period of revolution of the satellite (Moon) around its axis coincides with the period of its revolution around the central body (Earth). In this case, the satellite always faces the central body with the same side, since it rotates around its axis in the same time that it takes for it to turn around in orbit around its partner. Tidal capture occurs in the process of mutual motion and is characteristic of many large natural satellites of the planets of the Solar System, and is also used to stabilize some artificial satellites. When observing a synchronous satellite from the central body, only one side of the satellite is always visible. When viewed from this side of the satellite, the central body "hangs" motionless in the sky. From the reverse side of the satellite, the central body is never visible.

moon facts

There are lunar trees on Earth

Hundreds of tree seeds were brought to the moon during the 1971 Apollo 14 mission. Former USFS employee Stuart Roose took the seeds as a personal shipment for a NASA/USFS project.

Upon their return to Earth, these seeds were germinated, and the resulting lunar seedlings were planted throughout the United States, as part of the country's bicentennial celebrations in 1977.

There is no dark side

Place your fist on the table, fingers down. You see its back side. Someone on the other side of the table will see the knuckles. This is how we see the moon. Because it is tidally locked to our planet, we will always see it from the same vantage point.
The concept of the "dark side" of the moon has come from popular culture - think Pink Floyd's 1973 album "Dark Side of the Moon" and the 1990 thriller of the same name - and actually means the far, night, side. The one that we never see and which is opposite to the side closest to us.

In the time span, we see more than half of the moon, thanks to libration

The Moon moves along its orbital path and moves away from the Earth (at a rate of about one inch per year), accompanying our planet around the Sun.
If you were to look at the Moon up close as it speeds up and slows down during this journey, you would also see it wobble from north to south and west to east in a motion known as libration. As a result of this movement, we see a part of the sphere that is usually hidden (about nine percent).

However, we will never see another 41%.

Helium-3 from the Moon could solve Earth's energy problems

The solar wind is electrically charged and occasionally collides with the Moon and is absorbed by the rocks on the lunar surface. One of the most valuable gases in this wind that are absorbed by the rocks is helium-3, a rare isotope of helium-4 (commonly used for balloons).

Helium-3 is perfect for meeting the needs of fusion reactors with subsequent power generation.

One hundred tons of helium-3 could supply the Earth's energy needs for a year, according to Extreme Tech's calculations. The surface of the moon contains about five million tons of helium-3, while on Earth it is only 15 tons.

The idea is this: we fly to the moon, extract helium-3 in a mine, collect it in tanks and send it to Earth. True, this can happen very soon.

Is there any truth to the full moon madness myths?

Not really. The assumption that the brain, one of the most watery organs of the human body, is influenced by the moon is rooted in legends that are several millennia old, going back to the time of Aristotle.

Since the Moon's gravitational pull controls the tides of Earth's oceans, and since humans are 60% water (and 73% brain), Aristotle and the Roman scientist Pliny the Elder believed that the Moon should have a similar effect on ourselves.

This idea gave rise to the terms "lunar madness", "transylvanian effect" (which became widespread in Europe during the Middle Ages) and "lunar madness". The films of the 20th century added fuel to the fire, linking the full moon with psychiatric disorders, car accidents, murders and other incidents.

In 2007, the government of the British seaside town of Brighton ordered more police patrols to be sent during full moons (and on paydays too).

Yet science says there is no statistical relationship between human behavior and the full moon, according to several studies, one of which was conducted by American psychologists John Rotton and Ivan Kelly. It is unlikely that the Moon affects our psyche, rather, it simply adds light, in which it is convenient to commit crimes.

Missing Moonstones

In the 1970s, the Richard Nixon administration distributed rocks brought from the lunar surface during the Apollo 11 and Apollo 17 missions to the leaders of 270 countries.

Unfortunately, more than a hundred of these stones have gone missing and are believed to have gone to the black market. While working for NASA in 1998, Joseph Gutheinz even led a covert operation called "Lunar Eclipse" to stop the illegal sale of these stones.

What was all this fuss about? A pea-sized piece of moon rock was valued at $5 million on the black market.

The moon belongs to Dennis Hope

At least he thinks so.

In 1980, exploiting a loophole in the 1967 UN Space Property Treaty that "no country" can claim the solar system, Nevada resident Dennis Hope wrote to the UN and announced the right to private property. They didn't answer him.

But why wait? Hope opened a lunar embassy and began selling one-acre lots for $19.99 each. For the UN, the solar system is almost the same as the world's oceans: outside the economic zone and owned by every inhabitant of the Earth. Hope claimed to have sold off-world properties to celebrities and three former US presidents.

It is unclear whether Dennis Hope really does not understand the wording of the treaty, or whether he is trying to force the legislature to make a legal assessment of their actions so that the development of heavenly resources can begin under more transparent legal conditions.

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The eternal companion of the Earth, surrounded by romantic stories and scientific mysteries - the Moon - is shown as a fixed side 100% of the time. But why is the other side of the Moon not visible, are there mystical facts in the theory, or is it easy to explain the process from the point of view of physics and astronomy?

How is the turnover?

The Internet is full of photos and videos compiled from them throughout the year, which show exactly how we see the moon. The principles of celestial mechanics will help explain the phenomenon of one side of the cosmic body.

The planet rotates around its own axis and the Sun, and for the Moon, the "sun" becomes the Earth. It revolves around the personal axis and the planet. The speed of a celestial body going around the Earth is 100% the same as the speed of rotation around its own axis.

This means that the Moon rotates 100% synchronously around the planet and around the axis. This was not always the case, and the process of rotation at first looked different. Under the influence of the Earth's gravity and the tides, the planet slowly adjusted the satellite to its own characteristics. This is the reason why the far side of the Moon is not visible.

Practical rotation example

To understand exactly how the turnover occurs, you can conduct a small experiment:

1. Place a chair in the center of the room. This is Earth.
2. Stand at arm's length and place your fingertips in the center of the object. You are the Moon.
3. Start moving so that your fingers do not move. Make a full circle.

Did you notice that you were on one side of the object during the experiment? This also happens with the Earth's satellite.

Do we see exactly half from Earth?

The celestial body makes a complete revolution in only 27 days 7 hours and 43.1 minutes of time. If you look at the video, where the process is recorded for a whole year, it becomes clear that we see more than 50% of the Moon. On the opposite side, 41% of the surface remains inaccessible.

The rotation of the satellite does not always occur at the same speed. Lunar librations occur - when the satellite approaches the Earth at a minimum distance, the speed increases. As the lunar orbit gets farther, the speed slows down. It is also important to understand that celestial bodies rotate along an ellipsoidal trajectory.

More than 4 billion years ago, the Earth and its satellite formed, they rotated faster, and their speeds differed. Now the big planet has adjusted the small one for itself, and this is the main reason why the far side of the moon is not visible to the eye.

And beautiful, it has attracted the eyes of astronomers since ancient times. Even then, many of its features were noticed: phase changes, the time of sunrise and sunset, the duration of the lunar month. The ancient scientists also noticed the constancy of the face of the night star. True, in those days they did not wonder why the Moon turned to the Earth on 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 movement and interaction of space objects, supported by numerous observations, are very different from those that existed in ancient times. And almost everyone from school knows why the Moon is turned to the Earth on one side.

The beginning of the story

Today, one of the secrets that the Moon stubbornly refuses to reveal to us is its origin. Various studies carried out in order to obtain a definitive answer to this question have so far given rise to several versions. According to one of them, the Moon and the Earth are sisters, formed at about 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 indicating large differences in the composition of our planet and its satellite. A version is put forward to match them: the Moon was formed somewhere far away in space and, approaching the Earth, was captured by it. The hypothesis is also close to it, suggesting that several space objects were attracted, which after a while collided and formed the Moon. Finally, there is a theory according to which our planet is more like a mother for its satellite: the Moon appeared as a result of the collision of the Earth with a huge body. The knocked-out part and subsequently began to orbit around the "progenitor".

"satellite-planet" system

Be that as it may, it is only known for certain that the Moon is a natural satellite of the Earth. According to astronomical data, the night luminary at the time of its formation was located much closer to our planet. Moreover, it circled the Earth faster and turned first one side, then the other. This situation is typical for the initial stage of the evolution of the satellite-planet system. An example of the outcome of the development of such "relationships" is Pluto and Charon accompanying him. Both cosmic bodies are always turned to each other on the same side, their rotation is synchronized. But first things first.

Tidal acceleration

The young Moon immediately began to affect the Earth. This was expressed in the formation of tidal waves in the newly formed oceans, as well as in the crust. This effect has two main consequences. First, as a result of some features and its rotation, the tidal wave is ahead of the Moon. The entire mass of our planet, contained in such waves, in turn, affects the satellite, gives it acceleration, and the Moon begins to move faster, gradually moving away from the Earth. Secondly, in this process, an oppositely directed force arises, which slows down the movement of the continents. As a result, the speed of rotation of the Earth around its axis decreases, the length of the day increases.

The moon is moving away from our planet by about 4 cm per year. However, this is not an eternal process, and the probability of the Earth losing its satellite is negligible. The “escape” of the Moon will be completed at the moment when the rotation of the Earth around its axis is synchronized with the movement of the satellite in orbit. In this case, our planet will always look at the night star with the same side.

Similar process

It is easy to assume that the answer to the question of why the Moon is turned to the Earth on one side is associated with a similar phenomenon. Indeed, the Earth causes similar tidal waves in the bowels of the satellite. Since our planet is more massive, the force of its impact is much more tangible. Obeying it, the Moon has long synchronized its rotation with the movement around the Earth. As a result, the always visible and invisible side of the Moon appeared.

Slightly more than half

An attentive amateur astronomer can quickly find out that the face of the night star is still somewhat changing. The visible side of the Moon does not occupy exactly half of it. The orbit of the night star deviates from the plane of rotation of the Earth around the Sun (the ecliptic) by about 5º. In addition, its axis is displaced by 1.5º relative to the trajectory of the Moon. As a result, up to 6.5º above and below the satellite's poles are available for observation. This process is called the libration of the lunar latitude. Similarly, there is a fluctuation of the longitude of the satellite. It leads to a change in the speed of the moon, depending on the distance from the Earth. Due to this, the part of the satellite hidden from the eyes is reduced, 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 features of the effect of the planet's gravitational force on the satellite. However, as was said, a similar process after a certain time will lead to the fact that the Earth will also look at the night star with only one of its parts, regardless of what phase the Moon is in. According to the calculations of John Darwin, the grandson of the founder of the theory of evolution, the duration of the day by this moment will be equal to fifty days familiar to us. The distance separating the Earth and the Moon will increase in this case by about one and a half times. This will be the very ideal state of the satellite-planet system.

solar tides

There is, however, some possibility that the Moon is never destined to reach a sufficient distance. The reason for this possibility lies in the solar tides. The daylight has an effect similar to the lunar one both on the planet and on the satellite. If this fact is included in the theoretical construction of the future of two cosmic bodies, it turns out that at a certain distance from the Earth, the Moon will again begin to approach. This shortening of the distance will have devastating consequences. When the Moon is at a distance of 2.9, it will be torn apart by the forces of gravity.

One more "but"

However, this picture may not materialize. The fact is that according to forecasts, the removal of the moon, then its approach and, finally, death will take several trillion years. During this time, a catastrophe of a more serious scale can happen, at least for all life on the planet. The Sun will go out, having exhausted all the reserves of stellar fuel. Following this, all the conditions of interaction in the planetary system of the star will change.

Study

The other side of the Moon, inaccessible to direct observation, for a long time was a mystery, literally covered in darkness. It just gave me the opportunity to get to know her better. The first aircraft to photograph about 70% of the surface of the hidden part was the Soviet Luna-3. The photographs transmitted 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. Only two such formations were discovered, later named the Sea of ​​Moscow and the Sea of ​​Dreams.

giant crater

In 1965, the Zond-3 spacecraft headed for 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 earlier conclusions: 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 precisely on the dark side of the moon. Its length is 2250 km, and its depth is 12 km.

Hypotheses

Today, the mysteries are largely unraveled. However, the human mind tends to fantasize about those things and phenomena that are inaccessible to direct observation. Therefore, on the Internet, it is easy to find the most bizarre hypotheses related to the entire Moon as a whole or only to its hidden side. There are suggestions about the artificial origin of the satellite, its population with extraterrestrial intelligence and the deliberate concealment of one of the parties. There are also references to a mysterious space base located on the dark part of the satellite. Such versions are quite difficult both to confirm and to refute. No matter how true or false they are, they are based on the same reason that inspired people to explore space: the hope to find fellow minds in the vast expanses of the Universe, the desire to touch the unknown.

However, today it is quite precisely known why the Moon is turned to the Earth on 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 what phase the moon is in today and why. True, it cannot be said that we know everything about the earthly satellite and no discoveries are expected in the future. On the contrary, the night luminary, to match the ancient deities who personified it, remains mysterious and is in no hurry to share secrets. Mankind has yet to learn a lot of interesting things about the satellite of our planet. It is possible that a new stage of study, which began quite recently, will bear fruit in the near future. It is absolutely certain that the implementation of some NASA projects is of great importance in this sense. Among them is "Avatar", which consists in the development of a telepresence suit. It will allow, while on Earth, with the help of robots to conduct experiments on the Moon. Great hopes are also pinned on the colonization project, the implementation of which will result in the deployment of a scientific base on the satellite of our planet.