Can you see the other side of the moon. Why do we only see one side of the moon?

22.09.2019

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 once 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 general theory relativity, probably not. We can generally assume that the Moon does not rotate at all, it is the Universe that revolves around it, creating at the same time gravitational fields like the moon revolving in 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 of 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 human body, is influenced by the moon, is rooted in legends that are several millennia old, as far back as 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 ran a covert operation called " Moon eclipse to put an end to 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 presidents USA.

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.

Sources:

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 it is heavenly body at one point 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. Unique Phenomenon in the solar system - the 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.

The Moon floats high in the sky, bright, beautiful, with dark spots on a shiny disk. On a full moon, it resembles someone's round, good-natured, slightly mocking face. We always see her like this. And before us, for thousands of years, people looked at the exact same Moon and dark spots were distributed on it in the same way, which make it look like a human face. For thousands of years, people have been observing the changes in her bright face - from the thin sickle of a newborn month to the full radiance of her disk. Meanwhile, the Moon is a ball, the same as other planets, including our Earth, on which we live. But the moon never shows us its other side, we don't see it. Why?

The moon rotates on its axis and at the same time makes its way around the earth, because it is a satellite of the earth.

In twenty-nine and a half days, it makes its revolution around the Earth, and ... it takes the same amount of time to turn around its axis - it makes this revolution so slowly. And that's the whole point. That is why we always see only one side of it.

But how does it happen anyway? To make this clearer to you, let's do a little experiment. Take some small table (if there is no table - a chair or something else that is more convenient for you, what will be at hand). This chair will be an imaginary Earth, and you yourself will be the Moon, which wraps around the Earth. Start moving around the table, staying facing it all the time. At the beginning of your movement, for example, you saw a window in front of you, but then, as you make your circle around the table (that is, the Earth), this window will be behind you, and only at the end of the path you will see it again . This will only confirm that you have turned not only around the table, but also around yourself, your axis.

So is the Moon. It makes a revolution around the Earth and at the same time around its own axis.

But everyone now knows that we still saw the far side of the moon! How did it happen? Do you remember? .. However, no, you don’t remember this: in those years you were still too small! And this happened in 1959, when Soviet scientists launched an automatic station towards the Moon, which flew around our satellite and transmitted images from its other side to us on Earth. And people all over the world saw the far side of the moon for the first time!

And that's not all. A few years later, Soviet scientists again sent an automatic station towards the Moon, and this time again photographs were taken and sent to Earth. Thanks to the images, scientists then compiled the first map of both sides of the lunar surface, and then a new color map of the Moon with lunar seas, mountain ranges, the most important peaks, ring crater mountains, circuses.

While I was writing these pages, one piece of news followed another. Before I had time to tell you about the new color map, an amazing event took place: in February 1966, the world's first automatic station, our Soviet one, landed on the Earth's satellite! She made, as scientists say, a soft landing - this means that she landed on the moon smoothly, without breaking the equipment.

Having gently landed on the moon, the automatic station immediately began to work hard - it sent more and more pictures of the lunar surface, and these pictures were taken at close range. But this is extremely important! The images were large, accurate: scientists simply pounced on these amazing documents, carefully examined them; now they saw what the surface of the moon is like, what is on it, asserted or, on the contrary, changed their points of view about the lunar surface.

"Luna-9" made a soft landing on our satellite - the Moon. And shortly after that, in March 1966, Luna 10 was launched.

She began to fly around the Moon, that is, she became her artificial satellite, and the Luna-10 devices sent messages to Earth that researchers needed to know our celestial neighbor better.

"Luna-10" made its endless flight around the Moon, so close, familiar, and in the early days, the whole world could hear the melody of the communist anthem "The Internationale" coming from it.

After "Luna-10" there were also "Luna-11", and "Luna-12", and "Luna-14", and "Luna-16" ... Our messengers are constantly soaring into outer space, they are laying the first paths to our heavenly neighbor. And always the most difficult and most important thing is what is done for the first time!

However, the news of recent years is amazing! American astronauts, spaceship Apollo 11, Neil Armstrong, Edwin Aldrin and Michael Collins were the first to fly to the moon in July 1969, two of them, Neil Armstrong and Edwin Aldrin, set foot on its surface, the third, Michael Collins, was waiting for them, making circles around the moon .

The names of these cosmonauts will go down in history in the same way as the name of our glorious Gagarin, who was the first to go into space and see our planet Earth from the outside.

And a very special place in the study of our celestial neighbor is occupied by the amazing apparatus "Lunokhod-4", delivered to the Moon in November 1970. He worked hard there, doing the work of exploring the lunar surface for a man. This amazing apparatus worked only on a lunar day, when it could charge its batteries from the energy of the sun. And on a moonlit night, he rested, as they affectionately said about him: he slept.

Really, it all looks like a fairy tale.

And it may well happen that during the time this book is being printed, new amazing events will occur and we will have to expand this chapter, although at the beginning we were going to tell only about one thing: why we do not see the far side of the moon.

The constant satellite of our planet has excited the minds of people since the dawn of mankind. Even in ancient writings and runic Vedas, there are references to a constant night guest. The ancients already knew that the Moon controls many processes on the planet, back side which was endowed mystical properties. The moon (from the ancient Indian louksna - "light-eyed") is a sorceress who inspires poets and artists, the patroness of lovers and a symbol of romanticism.

Heroine of ancient legends

In the runic Vedas, we are talking about the three moons that accompanied the planet Midgard (Earth). The smallest Lelya, the average Month and the big Fattu. In the Russian Songs of the Gamayun bird, the first great Flood (112 thousand years ago) occurred as a result of the death of Lelya.

The second was destroyed by the Atlanteans Fatta, destroying Atlantis 13 thousand years ago. And people left one last and most mysterious moon with a rotation period of 29.5 days.

Oddly enough, but NASA research today puts forward a hypothesis about the existence of several satellites of the Earth in the distant past. They even created the "Trojans" model, where the satellites are called the "Trojan asteroid moon".

back side

Since the discovery of Galileo in 1635, for which he was burned by the Inquisition, the secrets of the hidden side of the moon have captured the minds of astronomers. Traditions are legends, but Galileo, with his primitive telescope with a magnification of only 3 times, examined the craters and mountains on the Moon, mapped the surface and made assumptions about the origin of the craters. Repeated observations only increased interest in the question: "Why do we see only one side of the moon?"

What versions and hypotheses have not been put forward! From the fact that it is flat, to the holographic model. What is on the far side of the moon, people saw with their own eyes in 1959, when the Soviet satellite Luna-3 took the first pictures of the invisible side of the moon.

Which Hidden Moon Are You?

From the pictures it became clear the following. The surface on the far side of the Moon is similar to the visible one, but there is a clear geographical asymmetry. 80% of the lunar seas were on visible side, and on the back there are only two large seas - Moscow and Dreams.

On the reverse side, the crust turned out to be thicker, more craters, they are wider and deeper. The largest with a diameter of 591 kilometers is the impact multi-ring crater Hertzsprung, whose depth is more than 4500 meters. The thickness of the bark is uneven, somewhere more, somewhere thinner. Why is there no answer yet.

There is an explanation

Why do we see only one side of the moon, explains the theory of libration. Both the Earth and the Moon rotate each on its own axis. The gravitational forces of our planet cause tidal forces acting on the Moon in a similar way to how it causes the tides to ebb and flow on Earth. Everyone knows that due to the attraction of the Moon, that part of our planet that is turned towards the satellite begins to move in waves in its direction (tidal humps). The mass of the Moon is many times less than the mass of our planet, respectively, the force of the Earth's influence on the Moon is many times greater. It was the balancing of these forces that synchronized the moon's rotation.

Seeing more than not seeing

A careful observer will notice changes in the lunar appearance. Astronomy reports that we see 59% of the entire surface of the moon. The longitude and latitude of the satellite fluctuate, which allows you to see an additional 6.5 degrees above and below the planet's poles. This happens as a result of the displacement of the Moon's axis relative to the trajectory of movement and the deviation of the ecliptic (plane of rotation) of the Earth towards the Sun. Here is such a coquette this Luna! The reverse side is still smaller.

Who is in charge?

Studies and calculations show that such a small planet with a diameter of almost 3500 kilometers, 384 kilometers away from the Earth, with a mass of 60% of the earth's, is necessary condition the existence of our house in solar system. And although our satellite is moving away from us at a speed of 38 mm per year, its loss does not threaten us within the lifetime of our Sun.

Earth - Moon: what is the future?

According to confirmed information, in Devon (410 million years ago) the day consisted of 21.8 hours. The moon was closer to us, the tides were stronger and more powerful. An increase in our day by 23 microseconds per year will lead to the fact that in five billion years the year on the planet will be reduced to nine days, and the Moon will make one revolution once a day in the future. And all this braking gravity of the moon. It slows the Earth's rotation around its axis by 0.00164 seconds per day.

Lunar program and space law

With the advent of the era of astronautics and long before space flights, attempts to claim their rights to space objects were made by countries and people. To prevent disputes such as who first flew to the moon - that and slippers, since 1937, attempts have been made to create a legal field in space exploration. As a result of the work of international lawyers in 1967, more than a hundred countries ratified the treaty that defines the principles of activities in outer space. It was the first document in the field of law in space, and others followed.

Here it is worth recalling that the sale and purchase of plots on the moon by about four million inhabitants of the planet has no legal force. The enterprising American Dennis Hope, who in 1980 declared himself the owner of all the space objects of our galaxy (well, at least excluded the Earth and the Sun), became a millionaire. But the buyers of his certificates own only beautiful pieces of paper.

Secrets of the Far Side of the Moon

Kilograms of soil from the moon, hundreds of experiments, 6 landings on the moon only in the US Apollo program - and many questions that have no answers. We present only the most interesting ones.

Why did the promising American project for lunar exploration "Avatars: Virtual Reality Suits" cease to be funded?
Where did the energy come from to broadcast from the American complex left on the moon that it was sending signals after more than two years, although its batteries are designed for only a year?
Calculations show that the Moon is hollow inside. What's in this 70 million cubic kilometer cavity? This fact is confirmed by the echo on the Moon, which was measured by the Apollo 12 crews. It was almost three and a half hours and spread over 40 kilometers.
What did the American astronaut Neil Armstrong actually see, the one who first flew to the moon and landed on it? After all, the falsification of the material shown to us about his landing has been proven.
Why, if our satellites from orbit take pictures of the streets with clearly visible license plates of cars, do we have such low resolution photos of the nearby planet Moon? The reverse side is generally represented by a minimum number of pictures. What are space corporations hiding from us?

Theories and conjectures have accumulated around the favorite of poets a lot. Psychics and astrologers, mystics and fortune-tellers connect the fate of people and the universe with a silent and sad night guest. A symbol of dreams and hopes, a talisman of dreamers and romantics, our constant companion the Moon - how many secrets have you not revealed yet and how many surprises will you present to people?

Why do we only see one side of the moon?

The moon rotates on its axis and at the same time makes its way around the earth, because it is a satellite of the earth.

So is the Moon. It makes a revolution around the Earth and at the same time around its own axis.

"Luna-9" made a soft landing on our satellite - the Moon. And shortly after that, in March 1966, Luna 10 was launched.

She began to make flights around the Moon, that is, she became her artificial satellite, and the Luna-10 instruments sent messages to Earth that scientific researchers needed in order to better know our celestial neighbor.

"Luna-10" made its endless flight around the Moon, so close, familiar, and in the early days, the whole world could hear the melody of the Communist anthem "The Internationale" coming from it.

After "Luna-10" there were also "Luna-11", and "Luna-12", and "Luna-14", and "Luna-16" ... All the time our messengers soar into outer space, they pave the first paths to our heavenly neighbor. And always the most difficult and most important thing is what is done for the first time!

However, the news of recent years is amazing! American astronauts, on the Apollo 11 spacecraft, Neil Armstrong, Edwin Aldrin and Michael Collins were the first to fly to the moon in July 1969, two of them, Neil Armstrong and Edwin Aldrin, set foot on its surface, the third, Michael Collins, was waiting them by making circles around the moon.

The names of these cosmonauts will go down in history in the same way as the name of our glorious Gagarin, who was the first to go into space and see our planet Earth from the outside.

And a very special place in the study of our celestial neighbor is occupied by the amazing apparatus "Lunokhod-1", delivered to the Moon in November 1970. He worked hard there, doing the work of exploring the lunar surface for a man. This amazing apparatus worked only on a lunar day, when it could charge its batteries from the energy of the sun. And on a moonlit night, he rested, as they affectionately said about him: he slept.

Really, it all looks like a fairy tale.

Falling stars

I don’t know about you, but I have always loved looking at the sky on quiet, cloudless evenings. I loved to look for constellations, some were difficult to find, and others were easy, such as Ursa Major or Cassiopeia.

On dark August nights, when the sky turns completely black, a wide bright road of stars is clearly visible - Milky Way. I stood with my head thrown back for a long time, so that my neck ached, and admired the dark sky, the stars and the silver moon.

But… what is it? A fiery dot traced the sky and went out. "A star has fallen," say those who saw it.

Star? No, it's something completely different, because the stars don't fall. These are small pebbles, dust particles that rush in outer space and are attracted by the Earth with terrible speed, fly into the atmosphere and burn up! We see this short flash and say: the star has fallen!

Little heavenly guests that burn up somewhere very high above the Earth are called meteors.

In August, October and November, the Earth, during its journey around the Sun, encounters especially a lot of cosmic dust, clouds, and pebbles. That is why at this time you can often see fiery flashes in the sky. This means that the Earth has met whole swarms of meteors and "space debris" on its way, and it flares up, flying into our atmosphere.

It happens that dozens of meteors immediately flare up in the sky and the "star shower" continues until the Earth passes the meteor shower.

Starry rain fell over Moscow more than twenty years ago, in 1946. Only we could not observe it, because the sky was covered with clouds. It was very annoying!

And there are not rains, but simply star showers! But this happens very rarely. At the end of the last century, several such showers were shed, they could be observed both in the sky of America and over Europe. It was a magnificent fireworks display arranged by nature itself.

Star showers, and especially star showers, are an exceptional phenomenon. You can live your life and not see them. But lonely fiery dots, flashing and dying in the dark August sky, lonely "shooting stars", we can always observe. Just remember: these are not stars - stars never fall! This is space dust. Dust particles flare up from strong air resistance when they fly into earth's atmosphere. Flash on and off!

Why is it day and night?

I woke up at eight o'clock. Outside the window - the pace of the night! I remembered that today is exactly December 22, the day of the winter solstice, when we, in the Northern Hemisphere, have the longest night of the year and the shortest day.

That year there was no snow for a long time, or rather, it was, only it didn’t lie for a long time - it melted. Mud, puddles, piercing wind and darkness - at four o'clock in the afternoon it is already necessary to turn on the light!

I do not like this time of the year, the time of a very late, protracted autumn, and I always look forward to the cherished December 22, when the sun, as they say, turns to summer, and winter to frost. After the winter solstice, the days begin to gradually arrive, and the night shortens, at first for some minute, and you look - in a month and an hour will increase. But winter comes into its own: frosts crackle, snow falls, and the twilight turns blue, almost purple ...

Day and night… Change of light and darkness… The most ordinary, most constant, unchanging phenomenon of nature, it goes on in an eternal routine. But why is this happening?

Once, in ancient times, not only children, but also adults asked themselves this question and did not find the right answer to it. Thousands of years passed before man understood and explained this phenomenon.