Why is the moon not a satellite of the earth? Why is the Moon called “moon”, “satellite of the earth” and “month”. Composition and surface of the Moon

In astronomy, a satellite is a body that revolves around a larger body and is held by the force of its gravity. The Moon is the Earth's satellite. The Earth is a satellite of the Sun. All planets of the solar system, with the exception of Mercury and Venus, have satellites.

Artificial satellites are man-made spacecraft orbiting the Earth or another planet. They are launched for various purposes: for scientific research, for studying weather, for communication.

The Earth-Moon system is unique in the solar system, since no planet has such a large satellite. The Moon is the only satellite of the Earth, but it is so big and close!

It is visible to the naked eye better than any planet through a telescope. Telescopic observations and close-up photographs show that its beautiful surface is uneven and extremely complex. Active study of the Earth's natural satellite began in 1959, when in our country and in the United States space probes and automatic interplanetary stations were launched towards the Moon for a comprehensive study, delivering samples of lunar rocks. And to this day, spacecraft bring a lot of information for the work of selenologists (scientists studying the Moon). Our satellite hides many mysteries. For a long time, people did not see its reverse side until 1959, when the Luna-3 automatic station photographed the invisible side of the lunar surface. Later, based on images obtained using the domestic Zond-3 station and the American Lunar Orbiter spacecraft, maps of the lunar surface were compiled. Flights of lunar automatic stations and landings of lunar expeditions helped to obtain answers to a number of unclear questions that worried astronomers. But, in turn, they posed new challenges for astronomers.

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Russian folk wisdom says: “Place a house where the sheep lie down.” And in China there is a custom not to start building a house until you are sure that the building site is free from “deep demons.” That is why most ancient cities and villages, both in Rus' and in many other countries, are located very well. Although there is, of course,...

The need to measure time arose among people already in ancient times. The first calendars appeared many thousands of years ago at the dawn of human civilization. People learned to measure periods of time, compare them with phenomena that were repeated periodically (the change of day and night, the change of phases of the moon, the change of seasons). Without the use of time units, people could not live, communicate with each other,...

In this constellation, two bright stars are very close to each other. They received their name in honor of the Argonauts Dioscuri - Castor and Pollux - twins, sons of 3eus, the most powerful of the Olympian gods, and Leda, a frivolous earthly beauty, brothers of Helen the beautiful - the culprit of the Trojan War. Castor was famous as a skilled charioteer, and Pollux as an unsurpassed fist fighter...

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We often have to observe how, on a clear sunny day, the shadow of a cloud, driven by the wind, runs across the Earth and reaches the place where we are. The cloud hides the Sun. During a solar eclipse, the Moon passes between the Earth and the Sun and hides it from us. Our planet Earth rotates around its axis during the day, and at the same time moves around...

Our Sun is an ordinary star, and all stars are born, live and die. Any star goes out sooner or later. Unfortunately, our Sun will not shine forever. Scientists once believed that the Sun was slowly cooling or “burning out.” However, we now know that if this had actually happened, then his energy would have been enough...

For a long time, almost until the end of the 18th century, Saturn was considered the last planet of the solar system. What distinguishes Saturn from other planets is its bright ring, discovered in 1655 by the Dutch physicist H. Huygens. Through a small telescope, two rings are visible, separated by a dark slit. There are actually seven rings. They all revolve around the planet. Scientists have proven through calculations that the rings are not solid, but...

In 1609, after the invention of the telescope, humanity was able to examine its space satellite in detail for the first time. Since then, the Moon has been the most studied cosmic body, as well as the first one that man managed to visit.

The first thing we have to figure out is what our satellite is? The answer is unexpected: although the Moon is considered a satellite, technically it is the same full-fledged planet as the Earth. It has large dimensions - 3476 kilometers across at the equator - and a mass of 7.347 × 10 22 kilograms; The Moon is only slightly inferior to the smallest planet in the Solar System. All this makes it a full participant in the Moon-Earth gravitational system.

Another such tandem is known in the Solar System, and Charon. Although the entire mass of our satellite is a little more than a hundredth of the mass of the Earth, the Moon does not orbit the Earth itself - they have a common center of mass. And the proximity of the satellite to us gives rise to another interesting effect, tidal locking. Because of it, the Moon always faces the same side towards the Earth.

Moreover, from the inside, the Moon is structured like a full-fledged planet - it has a crust, a mantle and even a core, and in the distant past there were volcanoes on it. However, nothing remains of the ancient landscapes - over the course of four and a half billion years of the Moon’s history, millions of tons of meteorites and asteroids fell on it, furrowing it, leaving craters. Some of the impacts were so strong that they tore through its crust all the way to its mantle. The pits from such collisions formed lunar maria, dark spots on the Moon that are easily visible from. Moreover, they are present exclusively on the visible side. Why? We will talk about this further.

Among cosmic bodies, the Moon influences the Earth the most - except, perhaps, the Sun. Lunar tides, which regularly raise water levels in the world's oceans, are the most obvious, but not the most powerful, impact of the satellite. Thus, gradually moving away from the Earth, the Moon slows down the rotation of the planet - a solar day has grown from the original 5 to the modern 24 hours. The satellite also serves as a natural barrier against hundreds of meteorites and asteroids, intercepting them as they approach the Earth.

And without a doubt, the Moon is a tasty object for astronomers: both amateurs and professionals. Although the distance to the Moon has been measured to within a meter using laser technology, and soil samples from it have been brought back to Earth many times, there is still room for discovery. For example, scientists are hunting for lunar anomalies - mysterious flashes and lights on the surface of the Moon, not all of which have an explanation. It turns out that our satellite hides much more than is visible on the surface - let's understand the secrets of the Moon together!

Topographic map of the Moon

Characteristics of the Moon

Scientific study of the Moon today is more than 2200 years old. The motion of a satellite in the Earth's sky, its phases and distance from it to the Earth were described in detail by the ancient Greeks - and the internal structure of the Moon and its history are studied to this day by spacecraft. Nevertheless, centuries of work by philosophers, and then physicists and mathematicians, have provided very accurate data about how our Moon looks and moves, and why it is the way it is. All information about the satellite can be divided into several categories that flow from each other.

Orbital characteristics of the Moon

How does the Moon move around the Earth? If our planet were stationary, the satellite would rotate in an almost perfect circle, from time to time slightly approaching and moving away from the planet. But the Earth itself is around the Sun - the Moon has to constantly “catch up” with the planet. And our Earth is not the only body with which our satellite interacts. The Sun, located 390 times farther than the Earth from the Moon, is 333 thousand times more massive than the Earth. And even taking into account the inverse square law, according to which the intensity of any energy source drops sharply with distance, the Sun attracts the Moon 2.2 times stronger than the Earth!

Therefore, the final trajectory of our satellite’s motion resembles a spiral, and a complex one at that. The axis of the lunar orbit fluctuates, the Moon itself periodically approaches and moves away, and on a global scale it even flies away from the Earth. These same fluctuations lead to the fact that the visible side of the Moon is not the same hemisphere of the satellite, but its different parts, which alternately turn towards the Earth due to the “swaying” of the satellite in orbit. These movements of the Moon in longitude and latitude are called librations, and allow us to look beyond the far side of our satellite long before the first flyby by spacecraft. From east to west, the Moon rotates 7.5 degrees, and from north to south - 6.5. Therefore, both poles of the Moon can be easily seen from Earth.

The specific orbital characteristics of the Moon are useful not only to astronomers and cosmonauts - for example, photographers especially appreciate the supermoon: the phase of the Moon in which it reaches its maximum size. This is a full moon during which the Moon is at perigee. Here are the main parameters of our satellite:

• The Moon's orbit is elliptical, its deviation from a perfect circle is about 0.049. Taking into account orbital fluctuations, the minimum distance of the satellite to the Earth (perigee) is 362 thousand kilometers, and the maximum (apogee) is 405 thousand kilometers.
• The common center of mass of the Earth and the Moon is located 4.5 thousand kilometers from the center of the Earth.
• A sidereal month - the complete passage of the Moon in its orbit - takes 27.3 days. However, for a complete revolution around the Earth and a change in lunar phases, it takes 2.2 days more - after all, during the time that the Moon moves in its orbit, the Earth flies a thirteenth part of its own orbit around the Sun!
• The Moon is tidally locked into the Earth - it rotates on its axis at the same speed as around the Earth. Because of this, the Moon is constantly turned to the Earth with the same side. This condition is typical for satellites that are very close to the planet.

• Night and day on the Moon are very long - half the length of an earthly month.
• During those periods when the Moon comes out from behind the globe, it is visible in the sky - the shadow of our planet gradually slides off the satellite, allowing the Sun to illuminate it, and then covers it back. Changes in the illumination of the Moon, visible from the Earth, are called ee. During the new moon, the satellite is not visible in the sky; during the young moon phase, its thin crescent appears, resembling the curl of the letter “P”; in the first quarter, the Moon is exactly half illuminated, and during the full moon it is most noticeable. Further phases - the second quarter and the old moon - occur in the reverse order.

Interesting fact: since the lunar month is shorter than the calendar month, sometimes there can be two full moons in one month - the second is called a “blue moon”. It is as bright as an ordinary light - it illuminates the Earth by 0.25 lux (for example, normal lighting inside a house is 50 lux). The Earth itself illuminates the Moon 64 times stronger - as much as 16 lux. Of course, all the light is not our own, but reflected sunlight.

• The Moon's orbit is inclined to the Earth's orbital plane and regularly crosses it. The satellite's inclination is constantly changing, varying between 4.5° and 5.3°. It takes more than 18 years for the Moon to change its inclination.
• The Moon moves around the Earth at a speed of 1.02 km/s. This is much less than the speed of the Earth around the Sun - 29.7 km/s. The maximum speed of the spacecraft achieved by the Helios-B solar probe was 66 kilometers per second.

Physical parameters of the Moon and its composition

It took people a long time to understand how big the Moon is and what it consists of. Only in 1753, the scientist R. Bošković was able to prove that the Moon does not have a significant atmosphere, as well as liquid seas - when covered by the Moon, the stars disappear instantly, when their presence would make it possible to observe their gradual “attenuation”. It took another 200 years for the Soviet station Luna 13 to measure the mechanical properties of the lunar surface in 1966. And nothing was known at all about the far side of the Moon until 1959, when the Luna-3 apparatus was able to take its first photographs.

The Apollo 11 spacecraft crew returned the first samples to the surface in 1969. They also became the first people to visit the Moon - until 1972, 6 ships landed on it and 12 astronauts landed. The reliability of these flights was often doubted - however, many of the critics' points were based on their ignorance of space affairs. The American flag, which, according to conspiracy theorists, “could not have flown in the airless space of the Moon,” is in fact solid and static - it was specially reinforced with solid threads. This was done specifically in order to take beautiful pictures - a sagging canvas is not so spectacular.

Many distortions of colors and relief shapes in the reflections on the helmets of the spacesuits in which they were looking for counterfeit were due to gold plating on the glass, which protects from ultraviolet. Soviet cosmonauts who watched the live broadcast of the astronaut landing also confirmed the authenticity of what was happening. And who can deceive an expert in his field?

And complete geological and topographic maps of our satellite are being compiled to this day. In 2009, the Lunar Reconnaissance Orbiter (LRO) space station not only delivered the most detailed images of the Moon in history, but also proved the presence of large amounts of frozen water on it. He also put an end to the debate about whether people were on the Moon by filming traces of the activities of the Apollo team from low lunar orbit. The device was equipped with equipment from several countries, including Russia.

Since new space states like China and private companies are joining the lunar exploration, new data is arriving every day. We have collected the main parameters of our satellite:

• The surface area of ​​the Moon occupies 37.9x10 6 square kilometers - about 0.07% of the total area of ​​the Earth. Incredibly, this is only 20% greater than the area of ​​all human-inhabited areas on our planet!
• The average density of the Moon is 3.4 g/cm 3 . It is 40% less than the density of the Earth - primarily due to the fact that the satellite is devoid of many heavy elements like iron, which our planet is rich in. In addition, 2% of the Moon's mass is regolith - small crumbs of rock created by cosmic erosion and meteorite impacts, the density of which is lower than normal rock. Its thickness in some places reaches tens of meters!
• Everyone knows that the Moon is much smaller than the Earth, which affects its gravity. The acceleration of free fall on it is 1.63 m/s 2 - only 16.5 percent of the entire gravitational force of the Earth. The astronauts' jumps on the Moon were very high, even though their spacesuits weighed 35.4 kilograms - almost like knight's armor! At the same time, they were still holding back: a fall in a vacuum was quite dangerous. Below is a video of the astronaut jumping from the live broadcast.

• Lunar maria cover about 17% of the entire Moon - mainly its visible side, which is covered by almost a third. They are traces of impacts from particularly heavy meteorites, which literally tore the crust off the satellite. In these places, only a thin, half-kilometer layer of solidified lava—basalt—separates the surface from the lunar mantle. Because the concentration of solids increases closer to the center of any large cosmic body, there is more metal in the lunar maria than anywhere else on the Moon.
• The main form of relief of the Moon is craters and other derivatives of impacts and shock waves from steroids. Huge lunar mountains and circuses were built and changed the structure of the surface of the Moon beyond recognition. Their role was especially strong at the beginning of the history of the Moon, when it was still liquid - the falls raised whole waves of molten stone. This also caused the formation of lunar seas: the side facing the Earth was hotter due to the concentration of heavy substances in it, which is why asteroids influenced it more strongly than the cool back side. The reason for this uneven distribution of matter was the gravity of the Earth, which was especially strong at the beginning of the Moon’s history, when it was closer.

• In addition to craters, mountains and seas, there are caves and cracks in the moon - surviving witnesses of the times when the bowels of the Moon were as hot as , and volcanoes were active on it. These caves often contain water ice, just like the craters at the poles, which is why they are often considered as sites for future lunar bases.
• The real color of the Moon's surface is very dark, closer to black. All over the Moon there are a variety of colors - from turquoise blue to almost orange. The light gray tint of the Moon from the Earth and in the photographs is due to the high illumination of the Moon by the Sun. Due to its dark color, the surface of the satellite reflects only 12% of all rays falling from our star. If the Moon were brighter, during full moons it would be as bright as day.

How was the Moon formed?

The study of lunar minerals and its history is one of the most difficult disciplines for scientists. The surface of the Moon is open to cosmic rays, and there is nothing to retain heat at the surface - therefore, the satellite heats up to 105 ° C during the day, and cools down to –150 ° C at night. The two-week duration of day and night increases the effect on the surface - and as a result, the minerals of the Moon change beyond recognition with time. However, we managed to find out something.

Today it is believed that the Moon is the product of a collision between a large embryonic planet, Theia, and the Earth, which occurred billions of years ago when our planet was completely molten. Part of the planet that collided with us (and it was the size of ) was absorbed - but its core, along with part of the surface matter of the Earth, was thrown into orbit by inertia, where it remained in the form of the Moon.

This is proven by the deficiency of iron and other metals on the Moon, already mentioned above - by the time Theia tore out a piece of earthly matter, most of the heavy elements of our planet were drawn by gravity inward, to the core. This collision affected the further development of the Earth - it began to rotate faster, and its axis of rotation tilted, which made the change of seasons possible.

Then the Moon developed like an ordinary planet - it formed an iron core, mantle, crust, lithospheric plates and even its own atmosphere. However, the low mass and composition poor in heavy elements led to the fact that the interior of our satellite quickly cooled, and the atmosphere evaporated from the high temperature and lack of a magnetic field. However, some processes inside still occur - due to movements in the lithosphere of the Moon, moonquakes sometimes occur. They represent one of the main dangers for future colonizers of the Moon: their scale reaches 5.5 points on the Richter scale, and they last much longer than those on Earth - there is no ocean capable of absorbing the impulse of movement of the Earth’s interior.

The main chemical elements on the Moon are silicon, aluminum, calcium and magnesium. The minerals that form these elements are similar to those on Earth and are even found on our planet. However, the main difference between the minerals of the Moon is the absence of exposure to water and oxygen produced by living beings, a high proportion of meteorite impurities and traces of the effects of cosmic radiation. The Earth's ozone layer was formed quite a long time ago, and the atmosphere burns most of the mass of falling meteorites, allowing water and gases to slowly but surely change the appearance of our planet.

Future of the Moon

The Moon is the first cosmic body after Mars that claims priority for human colonization. In a sense, the Moon has already been mastered - the USSR and the USA left state regalia on the satellite, and orbital radio telescopes are hiding behind the far side of the Moon from the Earth, a generator of a lot of interference on the air. However, what awaits our satellite in the future?

The main process, which has already been mentioned more than once in the article, is the moving away of the Moon due to tidal acceleration. It happens quite slowly - the satellite moves away no more than 0.5 centimeters per year. However, something completely different is important here. Moving away from the Earth, the Moon slows down its rotation. Sooner or later, a moment may come when a day on Earth will last as long as a lunar month - 29–30 days.

However, the removal of the Moon will have its limit. After reaching it, the Moon will begin to approach the Earth in turns - and much faster than it was moving away. However, it will not be possible to completely crash into it. 12–20 thousand kilometers from the Earth, its Roche lobe begins - the gravitational limit at which a satellite of a planet can maintain a solid shape. Therefore, the Moon will be torn into millions of small fragments as it approaches. Some of them will fall to Earth, causing a bombardment thousands of times more powerful than nuclear, and the rest will form a ring around the planet like . However, it will not be so bright - the rings of gas giants consist of ice, which is many times brighter than the dark rocks of the Moon - they will not always be visible in the sky. The ring of the Earth will create a problem for astronomers of the future - if, of course, by that time there is anyone left on the planet.

Colonization of the Moon

However, all this will happen in billions of years. Until then, humanity views the Moon as the first potential object for space colonization. However, what exactly is meant by “lunar exploration”? Now we will look at the immediate prospects together.

Many people think of space colonization as similar to New Age colonization of Earth - finding valuable resources, extracting them, and then bringing them back home. However, this does not apply to space - in the next couple of hundred years, delivering a kilogram of gold even from the nearest asteroid will cost more than extracting it from the most complex and dangerous mines. Also, the Moon is unlikely to act as a “dacha sector of the Earth” in the near future - although there are large deposits of valuable resources there, it will be difficult to grow food there.

But our satellite may well become a base for further space exploration in promising directions - for example, Mars. The main problem of astronautics today is restrictions on the weight of spacecraft. To launch, you have to build monstrous structures that require tons of fuel - after all, you need to overcome not only the gravity of the Earth, but also the atmosphere! And if this is an interplanetary ship, then it also needs to be refueled. This seriously constrains designers, forcing them to choose economy over functionality.

The moon is much better suited as a launch pad for spaceships. The lack of an atmosphere and low speed to overcome the Moon's gravity - 2.38 km/s versus 11.2 km/s on Earth - make launches much easier. And the satellite's mineral deposits make it possible to save on the weight of fuel - a stone around the neck of astronautics, which occupies a significant proportion of the mass of any apparatus. If the production of rocket fuel were developed on the Moon, it would be possible to launch large and complex spacecraft assembled from parts delivered from Earth. And assembly on the Moon will be much simpler than in low-Earth orbit - and much more reliable.

The technologies existing today make it possible, if not completely, then partially, to implement this project. However, any steps in this direction require risk. The investment of huge amounts of money will require research for the necessary minerals, as well as the development, delivery and testing of modules for future lunar bases. And the estimated cost of launching even the initial elements alone can ruin an entire superpower!

Therefore, the colonization of the Moon is not so much the work of scientists and engineers, but of the people of the whole world to achieve such valuable unity. For in the unity of humanity lies the true strength of the Earth.

The Moon is a natural satellite of our planet. Its influence is so great that astronomers often speak of the Earth-Moon conjunction not as a planet and a satellite, but as a double planet. Disputes about its origin still rage. Let's try to figure them out.

What is this strange “planet”?

The Moon influences almost every aspect of life on Earth, and the history of human civilization was no exception. Mammoth hunters also counted days using the phases of the moon. For the first civilizations, the Earth's satellite was a deity who controlled the most important thing - the agricultural cycle. In most ancient civilizations, the Moon was considered a powerful goddess to whom temples were built and sacrifices (sometimes human) were made. Eclipses of the Moon caused horror - the deity covered his face in anger, disasters were coming! In the Middle Ages, the Moon was considered the habitat of angels; in the Age of Enlightenment, people indulged in dreams of a race of Selenites living on the night luminary. Scientific progress quickly destroyed these naive ideas. The Moon turned out to be a small planet, lifeless and unattractive (from a human point of view). But it also turned out that the influence of our satellite on the processes occurring on Earth is very great - probably, without the Moon, the biosphere could not exist on Earth, and our planet would be similar to Mars or Venus. After all, it is the presence of the Moon that determines the most important climatic parameter - the inclination of the planet’s rotation axis relative to the plane of its orbit, which determines the nature of the change of seasons.

From the laws of celestial mechanics it is known that the inclination of the axis of rotation of planets is subject to fluctuations, an example of which is our neighbor Mars. As calculations performed by astronomers show, the angle between the equator of Mars and the plane of its orbit changed significantly. But the surface of the Red Planet contains numerous signs of a different past - channels, channels, sedimentary rocks (traces of ancient seas!). In the distant past, the planet's climate was warmer, and liquid water, and possibly life, existed on its surface. But some kind of catastrophe occurred, and Mars turned into an icy desert. Research shows that the most likely reason for the “freezing” of Mars was a change in the angle of the Martian axis. For the Earth, even an insignificant change in the angle of inclination of the axis to the ecliptic plane (by an amount of the order of a degree) can lead to an ice age. Meanwhile, Mars was rotating by tens of degrees, so grandiose climate disasters on it were inevitable. But on Earth, the angle of inclination of the axis relative to the orbital plane varied by no more than one or two degrees, which ensured amazing (by the standards of other planets) climate stability. A natural question arises - what is the reason for the unique stability of our planet?

How the Moon helps us

Most scientists believe that we should thank the Moon for the stability of the Earth’s rotation (and, accordingly, the climate) - it is thanks to it that chaotic fluctuations in the angle of inclination do not threaten the Earth. The hypothetical absence of a large satellite near the Earth would create conditions for very strong fluctuations in the angle between the equator and the orbit, which would make the climate on Earth unsuitable for life.

The beneficial role of the Moon was not limited to this, contributing to the emergence of life: it caused tides that contributed to the aeration of the seas. Perhaps even life itself first began in the intertidal zone! The movement of the Moon across the sky affects the life cycles of many organisms - a prime example is horseshoe crabs (marine arthropods distantly related to crayfish and crabs), which spawn only during a certain phase of the Moon.

It undoubtedly influenced the history of mankind. As an ideal celestial chronometer, the Earth's satellite significantly accelerated the appearance of the first calendars. Observations of the Moon (the closest celestial body) played a huge role in the development of astronomy. From them, ancient scientists concluded that the planets were spherical, and the movement of the Moon and its connection with sea tides made it possible in the 17th century to formulate the laws of universal gravitation.

Later, observations of the Moon contributed to the development of planetary science - after all, no other planet (except the Earth) has been studied in such detail! However, as knowledge about the Moon accumulated, a number of questions arose. The biggest mystery remained the origin of the Moon - many hypotheses for the origin of the night star were put forward, but none of them could explain all the facts. What are the main features of our satellite that caused such difficulties for scientists?

We list the main ones:

• the average density of the Moon is much less than the average density of the Earth, since the Moon has a very small core (if the Earth has about 30% of the mass of the planet, then the Moon has no more than 2-3%);
• on the Moon the content of heavy elements (thorium, uranium, titanium) is increased;
• but the ratio of oxygen isotopes in the earth’s and lunar crust is almost the same (but it varies greatly among different planets and meteorites from different parts of the solar system);
• the lunar crust is much thicker than the earth’s, which presumably indicates that all the matter composing it was once molten (but the Earth is believed to have never been completely molten);
• finally, the plane of the Moon’s orbit does not coincide with the equatorial plane of the Earth.

Among the numerous assumptions about the mechanism of the origin of our satellite, three hypotheses at different times gained the greatest popularity among scientists. Let's talk about them too.

Hypotheses for the origin of the Moon

According to one of these hypotheses, our companion was once an “independent” small planet in the solar system, revolving around the Sun. However, at some point, the free Moon came too close to the Earth - and the force of gravity captured it and transferred it to a new orbit, where the Moon was destined to revolve around our planet as a satellite.

Alas, calculations showed that this hypothesis cannot explain the features of the lunar orbit, and the similarity of the elements of the earth’s and lunar crust discovered after flights to the moon put an end to the “capture” version. Another popular hypothesis was the assumption of the joint formation of the Earth and the Moon (this hypothesis was put forward by the great Immanuel Kant). In accordance with it, the Moon and Earth were formed simultaneously - from one gas and dust cloud. The nascent proto-Earth gained such mass that particles of the cloud began to rotate in their orbits around it, gradually forming the proto-Moon.

This hypothesis is partly confirmed by the similarity of the isotopes of the Earth and the Moon, but this model does not explain the features of the lunar orbit at all.

To explain these contradictions, American astronomers Bill Hartmann and Donald Davis in 1975 put forward the impact hypothesis, which is currently considered the main one. According to it, when the Solar system was just in its infancy, two protoplanets were formed from a gas and dust cloud revolving around the Sun in the orbit of the future Earth - one of them was the young Earth, and the other (it was smaller, about the size of Mars) was named Theia. Under the influence of gravity, the planets began to move closer together, and 4.4 billion years ago, a grandiose catastrophe finally occurred - a collision of planets. The blow, fortunately, was tangential. Theia was destroyed, and the molten bowels of the earth splashed out into near-Earth orbit from the impact. The Moon was formed from this substance in about a hundred years. The impact spun the Earth - this is where the rapid (in comparison, for example, with Venus) change of days and nights comes from. This hypothesis well explains the inclination of the lunar orbit, the similarity of oxygen isotopes on Earth and the Moon, and the strange internal structure of the Moon. However, new research published in the journal Nature deals a fatal blow to these views.

After conducting a detailed study of samples of lunar rocks obtained by expeditions of the Apollo series of ships in the 70s of the 20th century, specialists from the University of Washington issued a negative verdict on the impact hypothesis: “If the old theory were correct, then more than half of the lunar rocks would consist of material that struck Planetoid Earth. But instead we see that the isotopic composition of the fragments of the Moon is very specific. The heavy isotopes of potassium found in the samples could only have formed under the influence of incredibly high temperatures. Only a very powerful collision, in which the planetoid and most of the Earth would evaporate on contact, could cause such an effect."

As a result, scientists proposed a new theory: instead of a colossal collision of planets, there were multiple collisions with smaller asteroids. The asteroid bombardment threw enough debris into Earth's orbit to form several small satellites, which eventually merged into one large one. This “Protoluna” continued to absorb objects in orbit until it was left in splendid isolation.

The study authors claim that their hypothesis best fits the data. However, skeptics immediately appeared who pointed out that the new hypothesis of the origin of the Moon does not explain all the oddities of the night star. So it’s too early to put an end to the debate about the Moon - the Earth’s satellite still retains its secret...

The Moon is the only celestial body that orbits planet Earth. This discovery was made in ancient times. At the same time, dark spots of various shapes were discovered on the surface of the Moon, which were later plotted on the map of the Moon. Since the 17th century, such spots began to be called seas.

At that time, it was believed that the satellite of our planet had water, therefore, its surface was covered with seas and oceans. And it occurred to the Italian astronomer Giovanni Riccioli to give them names that have remained to this day. The light parts of the surface belong to land.

Main characteristics of the Moon

The mass of the Moon is 7.3476*1022 kg, which is 81.3 times less than the mass of the Earth. The equatorial radius of the satellite is 1,737 km, which is 3.6 times less than the Earth’s. On average, the distance from the Earth to the Moon is 384,400 km.

Exploring the only satellite of our planet, scientists around the world are still at a loss on two questions:

• Can all space objects be called miraculous?
• Is it a coincidence that the Moon and planet Earth are where they are?

Doubts arise in the ranks of scientific minds for various reasons. So, for example, someone adjusted the diameter of the satellite in such a way, and someone positioned it at such a distance from the Sun that falling between it and the closest planet to the Moon, i.e. It is completely covered with earth. This phenomenon is known to everyone as a solar eclipse. However, at the same time, people would not be able to observe such an event if this “natural” satellite were different - larger or smaller or the size of Mars.

What is included in the Earth's satellite?

The entire Moon is entirely covered with regolith, which consists of dust and small fragments of meteorites. They often bombard the lunar surface, which is not protected by an atmospheric layer. Scientists believe that the thickness of such layers can be several centimeters or even tens of kilometers.

Schematically, the composition of the Moon can be indicated as follows:

1. Crust that can be extremely heterogeneous and vary from zero meters. For example, under the Moscow Sea it is separated from the surface by a basalt layer up to 600 m thick, and up to 105 km on the dark side of the Moon under the Korolev crater;
2. Three layers of mantle, starting with the outer mantle;
3. The core is the metallic center of the earth's satellite.

Interesting facts about the Moon

There is no "dark side"

In fact, both sides of the Moon receive equal amounts of sunlight, but only one of them is visible to Earth. This happens because the period of the Moon’s axial rotation converges with the orbital one. This means that the satellite is constantly facing the Earth one-sidedly. However, the “dark side” is being explored using spacecraft.

The Moon's influence on Earth's tides

The Moon's gravity forms the presence of two bulges on Earth. One is on the side facing the Moon, and the other is on the opposite side. Because of these protrusions, tides occur throughout the planet.

The Moon “escaping” from the Earth

Every year the satellite “runs away” from the Earth by 3.8 cm. Someone thought that in fifty billion years the Moon will simply run away. By then, it will have spent 47 days on its orbital flight.

The mass on the Moon is much less

The gravity of the Moon is less than that of the Earth, which is why the weight of people on the satellite will be 1/6 less. Actually, because of this, the astronauts jumped on it.

People on the Moon: 12 astronauts visited the satellite

Since 1969, Neil Armstrong was the first to set foot on the satellite during the Apollo 11 mission, and Eugene Cernan was the last to visit it in 1972. After that, there were only robots on the moon.

Lack of atmosphere on the Moon

On the lunar surface there is no protection from a wide variety of cosmic radiation, solar winds and meteorite bombardment. In addition, there are severe temperature fluctuations, no sounds can be heard, and the sky is always black.

Scientists claim lunar earthquakes

They claim that this is due to Earth's gravity. The astronauts used seismographs and calculated that there were cracks and breaks a couple of kilometers below the surface. It is believed that the satellite has a molten core.

The first artificial satellite on the Moon

It was a Soviet satellite of the Luna 1 program. In 1959, it flew next to the Moon at a distance of up to 6000 km, after which it entered solar orbit.

Is the Moon an artificial satellite?

In the early 1960s, Mikhail Vasin and Alexander Shcherbakov from the USSR Academy of Sciences stated that the Moon could have appeared unnaturally. This hypothesis has eight main postulates. Scientists have analyzed some mysterious nuances of everything connected with the satellite.

Eight lunar secrets

First secret: Is the moon a spaceship?

In reality, the orbit and size of the Moon at the physical level are not entirely possible. If everything were natural, then one would think that these are very unusual “quirks” of the cosmos. This is based on the fact that the Moon occupies a quarter of the size of the Earth, and the ratio of the sizes of satellites and planets is usually much smaller.

The distance between the Moon and the Earth is such that the visible dimensions are equivalent to those of the sun. Because of this, such a common phenomenon for earthlings as a total solar eclipse is observed. The same mathematical impossibility explains the location and mass ratio of two celestial objects. If the Moon had once been pulled by the Earth, it would have acquired a natural orbit. This orbit should have been elliptical, but it is surprisingly round.

The second secret: the presence of surface curvature

Scientists cannot explain the incredible curvature that the surface of the Moon has. The Moon's body is not round. After conducting geological studies, scientists decided that it is a planetoid, almost a hollow ball. At the same time, it is not clear how it can have such a strange structure and not collapse.

According to one of the versions proposed by the above-mentioned scientists, the lunar crust was made artificially. Supposedly it has a solid titanium frame. Russian scientists Vasin and Shcherbakov proved that the lunar crust and rocks contain an extraordinary level of titanium, in some places a layer of titanium at least 30 km thick.

The third secret: the presence of lunar craters

Scientists explain the huge number of meteorite craters on the lunar surface by the lack of an atmosphere. Cosmic bodies trying to make their way to Earth encounter kilometers of its atmosphere, where they burn up or disintegrate. The Moon does not have protective layers of atmosphere, so its surface is covered with all the traces left in it by meteorites. These are craters of various sizes.

However, no one explains why they have such little depth. And it looks as if the extremely durable material does not allow meteorites to penetrate deep into the satellite. Moreover, even for craters with a diameter of more than 150 km, the depth does not exceed four kilometers. This is inexplicable in terms of anything that has to do with science. Logically, there should be craters at least fifty kilometers deep.

The fourth secret: the presence of “lunar seas”

Scientists are still debating how the lunar oceans and seas could have formed. According to one version, hardened lava could have leaked out after a meteorite bombardment if it had been a hot planetoid.

However, based on physical characteristics, it is much more likely that the Moon, based on its size, is a cold body. In addition, questions also arise about where the “lunar seas” are located. Thus, it turned out that 80% of these objects are located on the side of the satellite visible to the Earth.

Fifth secret: the presence of mascons

Gravity on the lunar surface is not uniform. This was already noted by the crew of Apollo VIII when flying over the lunar seas. Mascons (from the English “Mass Concentration” - mass accumulation) are places where substances are concentrated with greater density or in large quantities. In the case of the Moon, this principle is closely related to the lunar maria, because the mascons are located under them.

The sixth secret: the presence of geographical asymmetry

A shocking fact for science, which has not yet been explained, is the presence of geographic asymmetry on the lunar surface. So, on the legendary “dark” side of the Moon there are many more mountains, craters, and other features in the relief. While most of the seas, on the contrary, are located on the side visible from the Earth.

The seventh secret: the presence of low density

The density of the Moon is no higher than 60% of the Earth's density. This fact proves why the Moon is not a planet, but a hollow object. In addition, some scientists believe that such a cavity may be of unnatural origin. However, given the location of the surface layers that have been identified, scientists dare to say that the Moon may look like a planet that could have formed “inside out.” And this is used as an argument in favor of the “artificial casting” version.

The Eighth Secret: Origin

In the last century, over a long period, three theories about the origin of the earth's satellite were accepted. Nowadays, the majority in the scientific community has accepted the hypothesis about the artificial origin of the Moon as not unfounded.

One theory suggests that the Moon is a fragment of the Earth. However, the differences in the characteristics of these two objects indicate the inconsistency of this theory. According to another theory, the presented celestial object was formed at the same time as our planet. Moreover, the material for their formation was the same cloud of cosmic gases. However, the previous conclusion is also valid regarding this judgment. Both objects should have at least similar structures.

The third theory suggests that the Moon, wandering through space, was attracted by the Earth's gravity. The big disadvantage of this theory is that the Moon's orbit is circular and cyclical. The proof would be an off-center or elliptical orbit.

However, there is another theory, the most incredible of all. With its help, many anomalies that are associated with the earth's satellite can be explained. If the Moon was constructed by intelligent beings, then the physical laws to which it is subject would not be equally applicable to other celestial objects.

There are many more interesting things in the versions about the origin of the Moon put forward by Soviet scientists. So far, this is only a small part of the real physical assessments of lunar anomalies. In addition, there are many other videos, photographs and research that prove that our “natural” satellite is not like that at all.

If you have any questions, leave them in the comments below the article. We or our visitors will be happy to answer them

Moon– satellite of planet Earth in the solar system: description, history of research, interesting facts, size, orbit, dark side of the Moon, scientific missions with photos.

Get away from the city lights on a dark night and admire the beautiful moonlight. Moon- this is the only earthly satellite that has been rotating around the Earth for more than 3.5 billion years. That is, the Moon has accompanied humanity since its appearance.

Due to its brightness and direct visibility, the satellite has been reflected in many myths and cultures. Some thought it was a deity, while others tried to use it to predict events. Let's take a closer look at the interesting facts about the Moon.

There is no "dark side"

• There are many stories where the far side of the moon appears. In reality, both sides receive the same amount of sunlight, but only one of them is visible to earth. The fact is that the time of the lunar axial rotation coincides with the orbital one, which means it is always turned to us with one side. But we explore the “dark side” with spacecraft.

The Moon influences Earth's tides

• Due to gravity, the Moon creates two bulges on our planet. One is on the side facing the satellite, and the second is on the opposite side. These ridges cause high and low tides throughout the Earth.

Luna tries to escape

• Every year the satellite moves away from us by 3.8 cm. If this continues, then in 50 billion years the Moon will simply run away. At that time, it will spend 47 days on the orbital flyby.

The weight on the Moon is much less

• The moon yields to Earth's gravity, so you'll weigh 1/6 less on the moon. That is why the astronauts had to move by jumping like a kangaroo.

12 astronauts have walked on the moon

• In 1969, Neil Armstrong was the first to set foot on satellite during the Apollo 11 mission. The last one was Eugene Cernan in 1972. Since then, only robots have been sent to the Moon.

No atmospheric layer

• This means that the surface of the Moon, as can be seen in the photo, is devoid of protection from cosmic radiation, meteorite impacts and solar wind. Serious temperature fluctuations are also noticeable. You will not hear any sounds, and the sky always seems black.

There are earthquakes

• Created by earth's gravity. The astronauts used seismographs and found that there were cracks and breaks several kilometers below the surface. The satellite is believed to have a molten core.

The first device arrived in 1959

• The Soviet spacecraft Luna 1 was the first to land on the Moon. It flew past the satellite at a distance of 5995 km, and then entered orbit around the Sun.

It is in 5th position in size in the system

• In diameter, the earth's satellite extends over 3475 km. The Earth is 80 times larger than the Moon, but they are about the same age. The main theory is that at the beginning of its formation, a large object crashed into our planet, tearing material into space.

We'll go to the moon again

• NASA plans to create a colony on the lunar surface so that there will always be people there. Work could begin as early as 2019.

In 1950, they planned to detonate a nuclear bomb on the satellite.

• It was a secret project during the Cold War - Project A119. This would show a significant advantage for one of the countries.

Size, mass and orbit of the Moon

The characteristics and parameters of the Moon should be studied. The radius is 1737 km, and the mass is 7.3477 x 10 22 kg, so it is inferior to our planet in everything. However, if compared with the celestial bodies of the Solar System, it is clear that it is quite large in size (in second position after Charon). The density indicator is 3.3464 g/cm 3 (in second place among moons after Io), and gravity is 1.622 m/s 2 (17% of Earth’s).

The eccentricity is 0.0549, and the orbital path covers 356400 – 370400 km (perihelion) and 40400 – 406700 km (aphelion). It takes 27.321582 days to completely circle the planet. In addition, the satellite is in a gravitational block, that is, it always looks at us from one side.

Composition and surface of the Moon

The Moon replicates the Earth and also has an inner and outer core, mantle and crust. The core is a solid iron sphere extending over 240 km. An outer core of liquid iron (300 km) is concentrated around it.

You can also find igneous rocks in the mantle, where there is more iron than ours. The crust extends for 50 km. The core covers only 20% of the entire object and contains not only metallic iron, but also small impurities of sulfur and nickel. You can see what the structure of the Moon looks like in the diagram.

Scientists were able to confirm the presence of water on the satellite, most of which is concentrated at the poles in shadowed crater formations and subsurface reservoirs. They think that it appeared due to the contact of the satellite with the solar wind.

Lunar geology diverges from Earth's. The satellite lacks a dense atmospheric layer, so there is no weather or wind erosion on it. Small size and low gravity lead to rapid cooling and lack of tectonic activity. You can note a huge number of craters and volcanoes. There are ridges, wrinkles, highlands and depressions everywhere.

The most noticeable contrast is between bright and dark areas. The first ones are called lunar hills, but the dark ones are called seas. The highlands were formed by igneous rocks, represented by feldspar and traces of magnesium, pyroxene, iron, olivine, magnetite and ilmenite.

Basalt rock formed the basis of the seas. Often these areas coincide with lowlands. You can mark channels. They are arcuate and linear. These are lava tubes, cooled and destroyed since volcanic hibernation.

An interesting feature is the lunar domes, created by the ejection of lava into the vents. They have gentle slopes and a diameter of 8-12 km. The wrinkles appeared due to the compression of tectonic plates. Most are found in the seas.

A notable feature of our satellite is impact craters formed when large space rocks fall. The kinetic impact energy forms a shock wave resulting in depression causing a lot of material to be ejected.

The craters range from small pits to 2500 km and a depth of 13 km (Aitken). The largest appeared in early history, after which they began to decrease. You can find approximately 300,000 depressions with a width of 1 km.

In addition, lunar soil is of interest. It was formed by impacts of asteroids and comets billions of years ago. The stones crumbled into fine dust that covered the entire surface.

The chemical composition of regolith differs depending on the position. If the mountains have a lot of aluminum and silicon dioxide, then the seas can boast of iron and magnesium. Geology was studied not only by telescopic observations, but also by analysis of samples.

Atmosphere of the Moon

The Moon has a weak atmosphere (exosphere), which causes its temperature to fluctuate greatly: from -153°C to 107°C. The analysis shows the presence of helium, neon and argon. The first two are created by solar winds, and the last is the decay of potassium. There is also evidence of frozen water reserves in craters.

Formation of the Moon

There are several theories about the appearance of the earth's satellite. Some people think that it’s all about the Earth’s gravity, which attracted the ready-made satellite. They formed together in the solar accretion disk. Age – 4.4-4.5 billion years.

The main theory is impact. It is believed that a large object (Theia) flew into the proto-Earth 4.5 billion years ago. The torn material began to rotate along our orbital path and formed the Moon. Computer models also confirm this. In addition, the tested samples showed almost identical isotopic compositions to ours.

Connection with the Earth

The Moon revolves around the Earth in 27.3 days (sidereal period), but both objects move around the Sun at the same time, so the satellite spends 29.5 days on one phase for the Earth (known phases of the Moon).

The presence of the Moon has an impact on our planet. First of all, we are talking about tidal effects. We notice this as sea levels rise. The Earth's rotation occurs 27 times faster than the Moon's. Ocean tides are also enhanced by the frictional coupling of water to the earth's rotation through ocean floors, water inertia, and basin oscillation.

Angular momentum accelerates the lunar orbit and lifts the satellite higher over a longer period. Because of this, the distance between us increases, and the earth's rotation slows down. The satellite moves away from us by 38 mm per year.

As a result, we will achieve mutual tidal locking, repeating the situation of Pluto and Charon. But this will take billions of years. So the Sun will most likely become a red giant and swallow us up.

Tides are also observed on the lunar surface with an amplitude of 10 cm for 27 days. Cumulative stress results in moon rays. And they last an hour longer because there is no water to dampen the vibrations.

Let's not forget about such a magnificent event as an eclipse. This happens if the Sun, satellite and our planet line up in a straight line. The lunar one appears if the full Moon appears behind the earth's shadow, and the solar one - the Moon is located between the star and the planet. During a total eclipse, you can see the solar corona.

The lunar orbit is tilted 5° to the Earth's, so eclipses occur at certain moments. The satellite needs to be near the intersection of orbital planes. The periodicity covers 18 years.

History of lunar observations

What does the history of lunar exploration look like? The satellite is located close and visible in the sky, so prehistoric inhabitants could have followed it. Early examples of recording lunar cycles begin in the 5th century BC. e. This was done by scientists in Babylon, who noted the 18-year cycle.

Anaxagoras of Ancient Greece believed that the Sun and satellite were large-scale spherical rocks, where the Moon reflected sunlight. Aristotle in 350 BC believed that the satellite is the boundary between the spheres of the elements.

The connection between the tides and the Moon was stated by Seleucus in the 2nd century BC. He also thought that the height would depend on the lunar position in relation to the star. The first distance from the Earth and size was obtained by Aristarchus. His data was improved by Ptolemy.

The Chinese began predicting lunar eclipses in the 4th century BC. They already knew then that the satellite reflected sunlight and was made in a spherical shape. Alhazen said that the sun's rays are not mirrored, but are emitted from each lunar area in all directions.

Until the advent of the telescope, everyone believed that they were seeing a spherical object, as well as a completely smooth one. In 1609, the first sketch by Galileo Galilei appeared, which depicted craters and mountains. This and observations of other objects helped advance Copernicus' heliocentric concept.

The development of telescopes has led to the detailing of surface features. All craters, mountains, valleys and seas were named in honor of scientists, artists and prominent figures. Until the 1870s all craters were considered volcanic formations. But it was only later that Richard Proctor suggested that they might be impact marks.

Exploring the Moon

The space era of lunar exploration has allowed us to take a closer look at our neighbor. The Cold War between the USSR and the USA caused all technologies to develop rapidly, and the Moon became the main target of research. It all started with spacecraft launches and ended with human missions.

The Soviet Luna program began in 1958, with the first three probes crashing onto the surface. But a year later, the country successfully delivered 15 devices and obtained the first information (information about gravity and images of the surface). The samples were delivered by missions 16, 20 and 24.

Among the models were innovative ones: Luna-17 and Luna-21. But the Soviet program was closed and the probes were limited to just surveying the surface.

NASA started launching probes in the 60s. In 1961-1965. There was a Ranger program that created a map of the lunar landscape. Then in 1966-1968. Rovers landed.

In 1969, a real miracle happened when Apollo 11 astronaut Neil Armstrong took the first step on the satellite and became the first man on the Moon. It was the culmination of the Apollo mission, which had originally aimed for human flight.

There were 13 astronauts on the Apollo 11-17 missions. They managed to extract 380 kg of rock. Also, all participants were engaged in various studies. After this there was a long lull. In 1990, Japan became the third country that managed to install its probe above the lunar orbit.

In 1994, the United States sent a ship to Clementine, who was creating a large-scale topographic map. In 1998, a scout managed to find ice deposits in the craters.

In 2000, many countries became eager to explore the satellite. ESA sent the SMART-1 spacecraft, which analyzed the chemical composition in detail for the first time in 2004. China launched the Chang'e program. The first probe arrived in 2007 and remained in orbit for 16 months. The second device was also able to capture the arrival of asteroid 4179 Toutatis (December 2012). Chang'e-3 launched a rover to the surface in 2013.

In 2009, the Japanese Kaguya probe entered orbit, studying geophysics and creating two full-fledged video reviews. Since 2008-2009, the first mission from the Indian ISRO Chandrayaan has been in orbit. They were able to create high-resolution chemical, mineralogical and photogeological maps.

NASA used the LRO spacecraft and the LCROSS satellite in 2009. The internal structure was examined by two additional NASA rovers launched in 2012.

The treaty between the countries states that the satellite remains a common property, so all countries can launch missions there. China is actively preparing a colonization project and is already testing its models on people who are locked in special domes for a long time. America, which also intends to populate the Moon, is not far behind.

Use the resources of our website to view beautiful and high-quality photos of the Moon in high resolution. Useful links will help you find out the maximum known amount of information about the satellite. To understand what the Moon is like today, just go to the appropriate sections. If you can’t buy a telescope or binoculars, then look at the Moon through an online telescope in real time. The image is constantly updated, showing the crater surface. The site also tracks the phases of the moon and its position in orbit. There is a convenient and fascinating 3D model of the satellite, the solar system and all celestial bodies. Below is a map of the lunar surface.

Earth satellites: from artificial to natural

Astronomer Vladimir Surdin about expeditions to the Moon, the Apollo 11 landing site and the equipment of the astronauts:

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