Earth's natural satellite is the Moon, a non-luminous body that reflects sunlight.

The study of the Moon began in 1959, when the Soviet apparatus Luna-2 landed on the Moon for the first time, and the Luna-3 apparatus was the first to take photographs of the far side of the Moon from space.

In 1966, Luna-9 landed on the moon and established a solid soil structure.

The first people to walk on the moon were Americans Neil Armstrong and Edwin Aldrin. This happened on July 21, 1969. For further study of the moon, Soviet scientists preferred to use automatic vehicles - lunar rovers.

General characteristics of the Moon

Average distance from Earth, km
a. e.	363 104 0,0024
a. e.	405 696 0,0027
Average distance between the centers of the Earth and the Moon, km
The inclination of an orbit to the plane of its orbit
Average orbital speed	1,022
Average radius of the Moon, km
Weight, kg
Equatorial radius, km
Polar radius, km
Average density, g / cm 3
Inclination to the equator, deg.

The mass of the moon is 1/81 of the mass of the earth. The position of the Moon in the orbit corresponds to one phase or another (Fig. 1).

Rice. 1. Moon phases

Moon phases- various positions relative to the Sun - new moon, first quarter, full moon and last quarter. During the full moon, the illuminated disk of the moon is visible, since the sun and moon are on opposite sides of the earth. During the new moon, the moon is on the side of the sun, so the side of the moon facing the earth is not illuminated.

The Moon always faces the Earth on one side.

The line that separates the illuminated part of the moon from the unlit part is called terminator.

In the first quarter, the Moon is visible at an angular distance of 90 "from the Sun, and the sun's rays illuminate only the right half of the Moon facing us. In the remaining phases, the Moon is visible to us in the form of a crescent. Therefore, in order to distinguish the growing Moon from the old one, we must remember: the old Moon resembles the letter “C”, and if the Moon is growing, then you can mentally draw a vertical line in front of the Moon and you will get the letter “P”.

Due to the proximity of the Moon to the Earth and its large mass, they form the Earth-Moon system. The Moon and the Earth rotate around their axes in the same direction. The plane of the Moon's orbit is inclined to the plane of the Earth's orbit at an angle of 5°9".

The places where the orbits of the Earth and the Moon intersect are called nodes of the lunar orbit.

Sidereal(from lat. sideris - star) a month is the period of rotation of the Earth around its axis and the same position of the Moon on the celestial sphere in relation to the stars. It is 27.3 Earth days.

synodic(from the Greek synod - connection) a month is the period of a complete change of lunar phases, that is, the period of the return of the moon to its original position relative to the moon and the sun (for example, from new moon to new moon). It averages 29.5 Earth days. The synodic month is two days longer than the sidereal month, since the Earth and the Moon rotate around their axes in the same direction.

The force of gravity on the Moon is 6 times less than the force of gravity on Earth.

The relief of the Earth's satellite is well studied. Visible dark areas on the surface of the Moon are called "seas" - these are vast waterless low-lying plains (the largest is "Oksan Bur"), and light areas - "continents" - these are mountainous, elevated areas. The main planetary structures of the lunar surface are ring craters with a diameter of up to 20-30 km and multi-ring circuses with a diameter of 200 to 1000 km.

The origin of the ring structures is different: meteorite, volcanic and shock-explosive. In addition, there are cracks, shifts, domes and fault systems on the surface of the Moon.

Studies of the Luna-16, Luna-20, Luna-24 spacecraft showed that the surface clastic rocks of the Moon are similar to terrestrial igneous rocks - basalts.

The meaning of the moon in the life of the earth

Although the mass of the Moon is 27 million times less than the mass of the Sun, it is 374 times closer to the Earth and has a strong influence on it, causing water to rise (tides) in some places and ebb in others. This happens every 12 hours and 25 minutes, since the Moon makes a complete revolution around the Earth in 24 hours and 50 minutes.

Due to the gravitational influence of the Moon and the Sun on the Earth, ebbs and flows(Fig. 2).

Rice. 2. Scheme of the occurrence of ebbs and flows on Earth

The most distinct and important in their consequences are tidal phenomena in the wave envelope. They are periodic rises and falls in the level of the oceans and seas, caused by the forces of attraction of the Moon and the Sun (2.2 times less than the lunar one).

In the atmosphere, tidal phenomena are manifested in semidiurnal changes in atmospheric pressure, and in the earth's crust - in the deformation of the solid matter of the Earth.

On Earth, there are 2 high tides at the point nearest and farthest from the Moon, and 2 low tides at points located at an angular distance of 90 ° from the Moon-Earth line. Allocate sizable tides, that occur on the new moon and full moon and quadrature in the first and last quarter.

In the open ocean, tidal phenomena are small. Water level fluctuations reach 0.5-1 m. In the inland seas (Black, Baltic, etc.), they are almost not felt. However, depending on the geographical latitude and the contours of the coastline of the continents (especially in narrow bays), the water during high tides can rise up to 18 m (the Bay of Fundy in the Atlantic Ocean off the coast of North America), 13 m on the western coast of the Sea of ​​Okhotsk. This creates tidal currents.

The main significance of tidal waves is that, moving from east to west following the apparent movement of the Moon, they slow down the axial rotation of the Earth and lengthen the day, change the shape of the Earth by reducing polar compression, cause pulsation of the Earth's shells, vertical displacements of the earth's surface, semidiurnal changes in atmospheric pressure, change the conditions of organic life in the coastal parts of the oceans and, finally, affect the economic activity of coastal countries. In a number of ports, ships can enter only at high tide.

After a certain period of time on Earth repeat solar and lunar eclipses. You can see them when the Sun, Earth and Moon are on the same line.

Eclipse- an astronomical situation in which one celestial body obscures light from another celestial body.

A solar eclipse occurs when the Moon comes between the observer and the Sun and blocks it. Since the Moon before the eclipse is facing us with its unlit side, there is always a new moon before the eclipse, i.e. the Moon is not visible. It seems that the Sun is covered by a black disk; an observer from the Earth sees this phenomenon as a solar eclipse (Fig. 3).

Rice. 3. Solar eclipse (relative sizes of bodies and distances between them are conditional)

A lunar eclipse occurs when the Moon, being in a straight line with the Sun and the Earth, falls into a cone-shaped shadow cast by the Earth. The diameter of the spot of the Earth's shadow is equal to the minimum distance of the Moon from the Earth - 363,000 km, which is about 2.5 times the diameter of the Moon, so the Moon can be completely obscured (see Fig. 3).

Lunar rhythms are repeated changes in the intensity and nature of biological processes. There are lunar-monthly (29.4 days) and lunar-daily (24.8 hours) rhythms. Many animals and plants reproduce during a certain phase of the lunar cycle. Lunar rhythms are characteristic of many marine animals and plants of the coastal zone. So, people noticed a change in well-being depending on the phases of the lunar cycle.

The moon is a satellite of our planet, attracting the eyes of scientists and just curious people from time immemorial. In the ancient world, both astrologers and astronomers devoted impressive treatises to her. The poets did not lag behind them. Today, little has changed in this sense: the orbit of the Moon, the features of its surface and interior are carefully studied by astronomers. Compilers of horoscopes also do not take their eyes off her. The influence of the satellite on the Earth is being studied by both. Astronomers study how the interaction of two cosmic bodies affects the movement and other processes of each. During the study of the Moon, knowledge in this area has increased significantly.

Origin

According to scientists, the Earth and the Moon were formed at about the same time. Both bodies are 4.5 billion years old. There are several theories about the origin of the satellite. Each of them explains certain features of the Moon, but leaves several unresolved questions. The giant collision theory is considered the closest to the truth today.

According to the hypothesis, the planet, similar in size to Mars, collided with the young Earth. The impact was tangential and caused the release into space of most of the matter of this cosmic body, as well as a certain amount of terrestrial "material". From this substance, a new object was formed. The radius of the Moon's orbit was originally sixty thousand kilometers.

The hypothesis of a giant collision explains well many features of the structure and chemical composition of the satellite, most of the characteristics of the Moon-Earth system. However, if we take the theory as a basis, some facts still remain incomprehensible. Thus, the deficiency of iron on the satellite can only be explained by the fact that by the time of the collision, differentiation of the inner layers had occurred on both bodies. To date, there is no evidence that such a thing took place. And yet, despite such counterarguments, the hypothesis of a giant collision is considered the main one all over the world.

Options

The Moon, like most other moons, has no atmosphere. Only traces of oxygen, helium, neon and argon have been found. The surface temperature in illuminated and dark areas is therefore very different. On the sunny side, it can rise to +120 ºС, and on the dark side it can drop to -160 ºС.

The average distance between the Earth and the Moon is 384,000 km. The shape of the satellite is almost a perfect sphere. The difference between the equatorial and polar radii is small. They are 1738.14 and 1735.97 km respectively.

A full revolution of the Moon around the Earth takes a little more than 27 days. The movement of the satellite across the sky for the observer is characterized by a change of phases. The time from one full moon to another is somewhat longer than the indicated period and is approximately 29.5 days. The difference arises because the Earth and the satellite are also moving around the Sun. The moon, in order to be in its original position, has to overcome a little more than one circle.

Earth-Moon system

The moon is a satellite, somewhat different from other similar objects. Its main feature in this sense is its mass. It is estimated at 7.35 * 10 22 kg, which is approximately 1/81 of the same parameter of the Earth. And if the mass itself is not something out of the ordinary in space, then its relationship with the characteristics of the planet is atypical. As a rule, the mass ratio in satellite-planet systems is somewhat smaller. Only Pluto and Charon can boast of a similar ratio. These two cosmic bodies some time ago began to be characterized as a system of two planets. It seems that this designation is also valid in the case of the Earth and the Moon.

Moon's orbit

The satellite makes one revolution around the planet relative to the stars in a sidereal month, which lasts 27 days, 7 hours and 42.2 minutes. The Moon's orbit is elliptical in shape. At different periods, the satellite is located either closer to the planet, or further away from it. The distance between the Earth and the Moon changes from 363,104 to 405,696 kilometers.

With the trajectory of the satellite, there is one more evidence in favor of the assumption that the Earth with the satellite must be considered as a system consisting of two planets. The orbit of the Moon is not located near the equatorial plane of the Earth (as is typical for most satellites), but practically in the plane of rotation of the planet around the Sun. The angle between the ecliptic and the satellite's trajectory is slightly more than 5º.

The orbit of the Moon around the Earth is influenced by many factors. In this regard, determining the exact trajectory of the satellite is not an easy task.

A bit of history

The theory explaining how the moon moves was laid back in 1747. The author of the first calculations that brought scientists closer to understanding the features of the satellite's orbit was the French mathematician Clairaut. Then, in the distant eighteenth century, the revolution of the Moon around the Earth was often put forward as an argument against Newton's theory. Calculations made with the use of strongly diverged from the apparent movement of the satellite. Clairaut solved this problem.

Such well-known scientists as d'Alembert and Laplace, Euler, Hill, Puiseux and others were engaged in the study of the issue. The modern theory of the revolution of the moon actually began with the work of Brown (1923). The research of the British mathematician and astronomer helped eliminate the discrepancies between calculations and observation.

Not an easy task

The movement of the Moon consists of two main processes: rotation around its axis and circulation around our planet. It would not be so difficult to derive a theory explaining the movement of the satellite if its orbit was not affected by various factors. This is the attraction of the Sun, and the features of the shape of the Earth, and other planets. Such influences perturb the orbit and predict the exact position of the Moon in a particular period becomes a difficult task. In order to understand what is the matter here, let us dwell on some parameters of the satellite's orbit.

Ascending and descending node, line of apsides

As already mentioned, the Moon's orbit is inclined to the ecliptic. The trajectories of two bodies intersect at points called ascending and descending nodes. They are located on opposite sides of the orbit relative to the center of the system, that is, the Earth. An imaginary line that connects these two points is referred to as a line of nodes.

The satellite is closest to our planet at the point of perigee. The maximum distance separates two space bodies when the Moon is at its apogee. The line joining these two points is called the line of apsides.

Orbit perturbations

As a result of the influence of a large number of factors on the movement of the satellite, in fact, it is the sum of several movements. Let us consider the most noticeable of the emerging perturbations.

The first one is node line regression. The straight line connecting the two points of intersection of the plane of the lunar orbit and the ecliptic is not fixed in one place. It moves very slowly in the direction opposite (that's why it is called regression) to the movement of the satellite. In other words, the plane of the Moon's orbit rotates in space. It takes 18.6 years for one complete rotation.

The line of apses is also moving. The movement of the straight line connecting the apocenter and periapsis is expressed in the rotation of the orbital plane in the same direction as the Moon moves. This happens much faster than in the case of a line of nodes. A complete revolution takes 8.9 years.

In addition, the lunar orbit experiences fluctuations of a certain amplitude. Over time, the angle between its plane and the ecliptic changes. The range of values ​​is from 4°59" to 5°17". Just as in the case of the line of nodes, the period of such fluctuations is 18.6 years.

Finally, the Moon's orbit changes its shape. It stretches a little, then returns to its original configuration again. In this case, the eccentricity of the orbit (the degree of deviation of its shape from a circle) changes from 0.04 to 0.07. Changes and return to the original position take 8.9 years.

Not so simple

In essence, the four factors that need to be considered during the calculations are not so many. However, they do not exhaust all perturbations of the satellite's orbit. In fact, each parameter of the Moon's motion is constantly affected by a large number of factors. All this complicates the task of predicting the exact location of the satellite. And accounting for all these parameters is often the most important task. For example, the calculation of the Moon's trajectory and its accuracy affects the success of the mission of the spacecraft sent to it.

The influence of the moon on the earth

The satellite of our planet is relatively small, but its impact is clearly visible. Perhaps everyone knows that it is the Moon that forms the tides on Earth. Here we must immediately make a reservation: the Sun also causes a similar effect, but due to the much greater distance, the tidal effect of the star is little noticeable. In addition, the change in the water level in the seas and oceans is also associated with the peculiarities of the rotation of the Earth itself.

The gravitational influence of the Sun on our planet is about two hundred times greater than that of the Moon. However, tidal forces primarily depend on the inhomogeneity of the field. The distance separating the Earth and the Sun smooths them out, so the impact of the Moon close to us is more powerful (twice as significant as in the case of the star).

A tidal wave is formed on that side of the planet, which is currently facing the night star. On the opposite side, there is also a tide. If the Earth were stationary, then the wave would move from west to east, located exactly under the moon. Its full revolution would be completed in 27-odd days, that is, in a sidereal month. However, the period around the axis is slightly less than 24 hours. As a result, the wave runs across the surface of the planet from east to west and completes one rotation in 24 hours and 48 minutes. Since the wave constantly meets with the continents, it moves forward in the direction of the Earth's movement and outstrips the planet's satellite in its run.

Deletion of the Moon's orbit

A tidal wave causes a huge mass of water to move. This directly affects the movement of the satellite. An impressive part of the mass of the planet is shifted from the line connecting the two bodies, and attracts the Moon to itself. As a result, the satellite experiences the influence of a moment of force, which accelerates its movement.

At the same time, the continents that run into the tidal wave (they move faster than the wave, since the Earth rotates at a higher speed than the Moon does), experience a force that slows them down. This leads to a gradual slowdown in the rotation of our planet.

As a result of the tidal interaction of two bodies, as well as the action and angular momentum, the satellite moves to a higher orbit. This reduces the speed of the moon. In orbit, it begins to move more slowly. Something similar happens with the Earth. It slows down, resulting in a gradual increase in the length of the day.

The Moon is moving away from the Earth by about 38 mm per year. The studies of paleontologists and geologists confirm the calculations of astronomers. The process of gradual slowing down of the Earth and the removal of the Moon began about 4.5 billion years ago, that is, from the moment the two bodies formed. The data of the researchers testify in favor of the assumption that earlier the lunar month was shorter, and the Earth rotated at a faster speed.

A tidal wave occurs not only in the waters of the oceans. Similar processes occur both in the mantle and in the earth's crust. However, they are less noticeable because these layers are not as malleable.

The removal of the Moon and the slowing down of the Earth will not happen forever. In the end, the period of rotation of the planet will be equal to the period of revolution of the satellite. The moon will "hover" over one area of ​​the surface. The earth and the satellite will always be turned by the same side to each other. Here it is appropriate to recall that part of this process has already been completed. It is tidal interaction that has led to the fact that the same side of the Moon is always visible in the sky. In space, there is an example of a system that is in such an equilibrium. These are already called Pluto and Charon.

The moon and earth are in constant interaction. It is impossible to say which of the bodies has more influence on the other. At the same time, both are exposed to the sun. Other, more distant, cosmic bodies also play a significant role. Accounting for all such factors makes it quite difficult to accurately build and describe a model of a satellite's motion in orbit around our planet. However, a huge amount of accumulated knowledge, as well as constantly improving equipment, makes it possible to more or less accurately predict the position of a satellite at any time and predict the future that awaits each object individually and the Earth-Moon system as a whole.

Basic information about the moon

© Vladimir Kalanov,
website"Knowledge is power".

The Moon is the closest large cosmic body to the Earth. The moon is the only natural satellite of the earth. Distance from the Earth to the Moon: 384400 km.

In the middle of the surface of the Moon, facing our planet, there are large seas (dark spots).
They are areas that have been flooded with lava for a very long time.

Average distance from Earth: 384,000 km (min. 356,000 km, max. 407,000 km)
Equator diameter - 3480 km
Gravity - 1/6 of the earth
The period of revolution of the Moon around the Earth is 27.3 Earth days
The period of rotation of the Moon around its axis is 27.3 Earth days. (The period of revolution around the Earth and the period of rotation of the Moon are equal, which means that the Moon always faces the Earth on one side; both planets revolve around a common center located inside the globe, so it is generally accepted that the Moon revolves around the Earth.)
Sidereal month (phases): 29 days 12 hours 44 minutes 03 seconds
Average orbital speed: 1 km/s.
The mass of the moon is 7.35 x10 22 kg. (1/81 earth mass)
Surface temperature:
- maximum: 122°C;
- minimum: -169°C.
Average density: 3.35 (g/cm³).
Atmosphere: absent;
Water: not available.

It is believed that the internal structure of the Moon is similar to the structure of the Earth. The moon has a liquid core with a diameter of about 1500 km, around which there is a mantle about 1000 km thick, and the upper layer is a crust covered on top with a layer of lunar soil. The most superficial layer of soil consists of regolith, a gray porous substance. The thickness of this layer is about six meters, and the thickness of the lunar crust is on average 60 km.

People have been observing this amazing night star for thousands of years. Every nation has songs, myths and fairy tales about the Moon. Moreover, the songs are mostly lyrical, sincere. In Russia, for example, it is impossible to meet a person who would not know the Russian folk song "The Moon Shines", and in Ukraine everyone loves the beautiful song "Nich Yaka Misyachna". However, I cannot vouch for everyone, especially young people. After all, there may, unfortunately, be those who are more to the liking of the "Rolling Stones" and their fatal effects. But let's not digress from the topic.

Interest in the Moon

People have been interested in the Moon since ancient times. Already in the 7th century BC. Chinese astronomers found that the time intervals between the same phases of the moon are 29.5 days, and the length of the year is 366 days.

At about the same time in Babylon, stargazers published a kind of cuneiform book on astronomy on clay tablets, which contained information about the moon and the five planets. Surprisingly, the stargazers of Babylon already knew how to calculate the time periods between lunar eclipses.

Not much later, in the VI century BC. The Greek Pythagoras already argued that the moon does not shine by its own light, but reflects sunlight to the Earth.

Based on observations, accurate lunar calendars for various regions of the Earth have long been compiled.

Observing dark areas on the surface of the moon, the first astronomers were sure that they were seeing lakes or seas similar to those on Earth. They did not yet know that it was impossible to talk about any water, because on the surface of the Moon the temperature during the day reaches plus 122°C, and at night - minus 169°C.

Before the advent of spectral analysis, and then space rockets, the study of the Moon was essentially reduced to visual observation or, as they say now, to monitoring. The invention of the telescope expanded the possibilities of studying both the Moon and other celestial bodies. Elements of the lunar landscape, numerous craters (of various origins) and "seas" subsequently began to receive the names of prominent people, mostly scientists. On the visible side of the Moon appeared the names of scientists and thinkers of different eras and peoples: Plato and Aristotle, Pythagoras and, Darwin and Humboldt, and Amundsen, Ptolemy and Copernicus, Gauss and, Struve and Keldysh, and Lorentz and others.

In 1959, the Soviet automatic station photographed the far side of the moon. To the existing lunar riddles, another one was added: in contrast to the visible side, there are almost no dark areas of "seas" on the far side of the Moon.

The craters discovered on the far side of the Moon, at the suggestion of Soviet astronomers, were named after Jules Verne, Giordano Bruno, Edison and Maxwell, and one of the dark areas was called the Sea of ​​Moscow. The names are approved by the International Astronomical Union.

One of the craters on the visible side of the Moon is named Hevelius. This is the name of the Polish astronomer Jan Hevelius (1611-1687), who was one of the first to view the moon through a telescope. In his native city of Gdansk, Hevelius, a lawyer by education and a passionate lover of astronomy, published the most detailed atlas of the moon at that time, calling it "Selenography". This work brought him worldwide fame. The atlas consisted of 600 folio pages and 133 engravings. Hevelius himself typed the texts, made engravings and printed the edition himself. He did not begin to guess which of the mortals is worthy and which is not worthy to imprint his name on the eternal tablet of the lunar disk. Hevelius gave earthly names to the mountains discovered on the surface of the Moon: Carpathians, Alps, Apennines, Caucasus, Riphean (i.e. Ural) mountains.

Much knowledge about the Moon has been accumulated by science. We know that the Moon shines by sunlight reflected from its surface. The moon is constantly turned to the Earth on one side, because its complete revolution around its own axis and the revolution around the Earth are the same in duration and equal to 27 Earth days and eight hours. But why, for what reason, did such synchronicity arise? This is one of the mysteries.

Moon phases

When the Moon rotates around the Earth, the lunar disk changes its position relative to the Sun. Therefore, an observer on Earth sees the Moon successively as a full bright circle, then as a crescent, becoming a thinner crescent until the crescent completely disappears from view. Then everything repeats itself: the thin crescent of the Moon reappears and increases to a crescent, and then to a full disk. The phase when the moon is not visible is called the new moon. The phase during which a thin "crescent", appearing on the right side of the lunar disk, grows to a semicircle, is called the first quarter. The illuminated part of the disk grows and captures the entire disk - the full moon phase has come. After that, the illuminated disk decreases to a semicircle (the last quarter) and continues to decrease until the narrow "crescent" on the left side of the lunar disk disappears from the field of view, i.e. the new moon comes again and everything repeats.

A complete change of phases occurs in 29.5 Earth days, i.e. within about a month. That is why in popular speech the moon is called the month.

So, there is nothing miraculous in the phenomenon of changing the phases of the moon. It is also not a miracle that the Moon does not fall to the Earth, although it experiences the powerful gravitation of the Earth. It does not fall because the gravitational force is balanced by the inertia force of the Moon's motion in orbit around the Earth. The law of universal gravitation, discovered by Isaac Newton, operates here. But ... why did the movement of the Moon around the Earth, the movement of the Earth and other planets around the Sun arise, what was the reason, what force initially made these celestial bodies move in this way? The answer to this question must be sought in the processes that took place when the Sun and the entire solar system arose. But where can one get knowledge about what happened many billions of years ago? The human mind can look both into the unimaginably distant past and into the future. This is evidenced by the achievements of many sciences, including astronomy and astrophysics.

Landing a man on the moon

The most impressive and, without exaggeration, epochal achievements of scientific and technical thought in the 20th century were: the launch in the USSR of the first artificial satellite of the Earth on October 7, 1957, the first manned flight into space, performed by Yuri Alekseevich Gagarin on April 12, 1961, and the landing of a man on the Moon, carried out by the United States of America July 21, 1969.

To date, 12 people have already walked on the moon (they are all US citizens), but the glory always belongs to the first. Neil Armstrong and Edwin Aldrin were the first people to walk on the moon. They landed on the moon from the Apollo 11 spacecraft, which was piloted by astronaut Michael Collins. Collins was on a spacecraft that was in orbit around the moon. After completing work on the lunar surface, Armstrong and Aldrin launched from the Moon on the lunar compartment of the spacecraft and, after docking in lunar orbit, transferred to the Apollo 11 spacecraft, which then headed for Earth. On the Moon, the astronauts made scientific observations, took pictures of the surface, collected samples of lunar soil and did not forget to plant the national flag of their homeland on the Moon.

Left to right: Neil Armstrong, Michael Collins, Edwin "Buzz" Aldrin.

The first astronauts showed courage and real heroism. These words are standard, but they fully apply to Armstrong, Aldrin and Collins. Danger could await them at every stage of the flight: when starting from the Earth, when entering the orbit of the Moon, when landing on the Moon. And where was the guarantee that they would return from the Moon to the ship piloted by Collins, and then safely reach the Earth? But that's not all. No one knew in advance what conditions would meet people on the Moon, how their space suits would behave. The only thing that the astronauts could not be afraid of was that they would not drown in lunar dust. The Soviet automatic station "Luna-9" in 1966 landed on one of the plains of the Moon, and its instruments reported: there is no dust! By the way, the general designer of Soviet space systems, Sergei Pavlovich Korolev, even earlier, in 1964, based solely on his scientific intuition, stated (and in writing) that there is no dust on the Moon. Of course, this does not mean the complete absence of any dust, but the absence of a layer of dust of a noticeable thickness. Indeed, earlier, some scientists assumed the presence on the Moon of a layer of loose dust up to 2-3 meters deep or more.

But Armstrong and Aldrin were personally convinced of the correctness of Academician S.P. Koroleva: There is no dust on the Moon. But this was already after landing, and when entering the surface of the moon, the excitement was great: Armstrong's pulse rate reached 156 beats per minute, the fact that the landing took place in the "Sea of ​​​​calm" was not very reassuring.

An interesting and unexpected conclusion based on the study of the features of the surface of the Moon was made quite recently by some Russian geologists and astronomers. In their opinion, the relief of the side of the Moon facing the Earth is very similar to the surface of the Earth, as it was in the past. The general outlines of the lunar "seas" are, as it were, an imprint of the contours of the earth's continents, which they were 50 million years ago, when, by the way, almost the entire land of the Earth looked like one huge continent. It turns out that for some reason the "portrait" of the young Earth was imprinted on the surface of the Moon. This probably happened when the lunar surface was in a soft, plastic state. What was this process (if there was one, of course), as a result of which such a "photographing" of the Earth by the Moon occurred? Who will answer this question?

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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 problem about coins 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 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 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 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, using 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 not clear whether Dennis Hope really does not understand the wording of the treaty, or whether he is trying to force the legislative forces 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 Earth and the Moon are in continuous rotation around their own axis and around the Sun. The moon also revolves around our planet. In this regard, we can observe in the sky numerous phenomena associated with celestial bodies.

nearest space body

The Moon is a natural satellite of the Earth. We see it as a luminous ball in the sky, although by itself it does not emit light, but only reflects it. The source of light is the Sun, whose radiance illuminates the lunar surface.

Each time you can see a different moon in the sky, its different phases. This is a direct result of the rotation of the Moon around the Earth, which, in turn, revolves around the Sun.

Moon exploration

Many scientists and astronomers have been observing the Moon for many centuries, but the study of the Earth’s satellite began in 1959 in a truly, so to speak “live” way. Then the Soviet interplanetary automatic station "Luna-2" reached this celestial body. At that time, this device was not able to move on the surface of the Moon, but could only record some data with the help of instruments. The result was a direct measurement of the solar wind, a stream of ionized particles emanating from the Sun. Then a spherical pennant with the emblem of the Soviet Union was delivered to the Moon.

The Luna-3 spacecraft, launched a little later, took from space the first photograph of the far side of the Moon, which is not visible from Earth. A few years later, in 1966, another automatic station called "Luna-9" landed on the earth's satellite. She was able to make a soft landing and transmit telepanoramas to Earth. For the first time, earthlings saw a television show directly from the moon. Prior to the launch of this station, there were several unsuccessful attempts at a soft "lunar landing". With the help of studies carried out with this apparatus, the meteor-slag theory about the external structure of the Earth's satellite was confirmed.

The journey from Earth to the Moon was carried out by the Americans. The first people to walk on the moon were Armstrong and Aldrin. This event took place in 1969. Soviet scientists wished to explore the celestial body only with the help of automation, they used lunar rovers.

Characteristics of the Moon

The average distance between the Moon and the Earth is 384,000 kilometers. When the satellite is closest to our planet, this point is called Perigee, the distance is 363 thousand kilometers. And when there is a maximum distance between the Earth and the Moon (this state is called apogee), it is 405 thousand kilometers.

The Earth's orbit has an inclination with respect to the orbit of its natural satellite - 5 degrees.

The moon moves in its orbit around our planet at an average speed of 1.022 kilometers per second. And in an hour it flies approximately 3681 kilometers.

The radius of the Moon, unlike the Earth (6356), is approximately 1737 kilometers. This is an average value, since it can vary at different points on the surface. For example, at the lunar equator, the radius is slightly larger than average - 1738 kilometers. And in the region of the pole, it is slightly less - 1735. The moon is also more of an ellipsoid than a ball, as if it had been "flattened" a little. The same feature exists in our Earth. The shape of our home planet is called the geoid. It is a direct consequence of rotation around the axis.

The mass of the Moon in kilograms is approximately 7.3 * 1022, the Earth weighs 81 times more.

Moon phases

The phases of the moon are the different positions of the Earth's satellite relative to the Sun. The first phase is the new moon. Then comes the first quarter. After that comes the full moon. And then the last quarter. The line separating the illuminated part of the satellite from the dark part is called the terminator.

The new moon is the phase when the Earth's satellite is not visible in the sky. The moon is not visible because it is closer to the Sun than our planet, and accordingly, its side facing us is not illuminated.

The first quarter - half of the heavenly body is visible, the star illuminates only its right side. Between the new moon and the full moon, the moon "grows". It is at this time that we see a shining crescent in the sky and call it the "growing month."

Full Moon - The moon is visible as a bright circle that illuminates everything with its silver light. The light of the heavenly body at this time can be very bright.

The last quarter - the Earth's satellite is only partially visible. In this phase, the Moon is called "old" or "waning", because only its left half is illuminated.

It is easy to distinguish a growing month from a waning moon. When the moon is waning, it resembles the letter "C". And when it grows, if you put a stick on the month, you get the letter "P".

Rotation

Since the Moon and Earth are close enough to each other, they form a single system. Our planet is much larger than its satellite, so it affects it with its force of attraction. The moon faces us with one side all the time, so before space flights in the twentieth century, no one saw the other side. This is because the Moon and the Earth rotate around their axis in the same direction. And the rotation of the satellite around its axis lasts the same time as the rotation around the planet. In addition, together they make a revolution around the Sun, which lasts 365 days.

But at the same time, it is impossible to say in which direction the Earth and the Moon rotate. It would seem that this is a simple question, either clockwise or counterclockwise, but the answer can only depend on the point of reference. The plane on which the Moon's orbit is located is slightly inclined relative to that of the Earth, the angle of inclination is approximately 5 degrees. The points where the orbits of our planet and its satellite intersect are called nodes of the lunar orbit.

Sidereal and Synodic

A sidereal or stellar month is the length of time it takes for the Moon to revolve around the Earth, returning to the same place it started from, relative to the stars. This month lasts 27.3 days flowing on the planet.

The synodic month is the period during which the Moon makes a full revolution, only relative to the Sun (the time during which the lunar phases change). Lasts 29.5 Earth days.

The synodic month is two days longer than the sidereal month due to the rotation of the Moon and the Earth around the Sun. Since the satellite revolves around the planet, and that, in turn, revolves around the star, it turns out that in order for the satellite to go through all its phases, additional time is needed in excess of a full revolution.