Why are other satellites of the planets called moons. Why is the moon a satellite? You may be interested

The universe was left without a phenomenon! The "dark energy" that has been searched for for 20 years does not exist at all! Such sensational reports came from the Congress of the American Astronomical Society. It was not only the famous "dark energy" that was rejected.

Much stronger was the statement that the universe does not scatter with acceleration, as physicists claimed. By the way, in 2011 it was for this discovery that the Australian and two Americans were awarded the Nobel Prize. And now everything is turning upside down: it is necessary to revise the generally accepted model of the Universe. This conclusion follows from the work of astronomers from the South Korean University of Yonse and the University of Lyon.

Recall that the "dark energy" long history... The great Einstein stood at its origins, and supposedly it was the most main mistake his life.

He tried in 1917 to apply the newly created by him General theory relativity to describe the universe. And suddenly I ran into an unsolvable problem. According to centuries-old concepts, the Universe was considered eternal and unchanging, in a word, static. But in Einstein's formulas, she suddenly came to life, moved. How to bring her peace back? The scientist introduced a new element into his equations, the so-called cosmological constant. And everything returned to its place. Peace reigned.

However, not for long. In 1929, the American astronomer Hubble discovered that the universe is expanding, and in it the Einstein constant is simply superfluous. She left the stage. It seemed like forever. Many years passed, and she suddenly returned from almost nothing. Everything changed after observing supernovae, scientists made one of the most sensational discoveries of the 20th century: the Universe is scattering with acceleration. This phenomenon was called universal antigravitation.

He changed the picture of the scientific world. Until recently, she seemed so slender. The Big Bang spawned a universe with many galaxies. Having received a powerful initial impulse, they scatter, but due to mutual attraction this happens with a slowdown. And now, it turns out, everything is completely different, but exactly the opposite.

What drives them? Does it make you fly with acceleration, overcome the force of gravity? Physicists today believe that this is a phenomenon that they call "dark energy" associated with the very same Einstein's constant. The most amazing thing is that in the first 7-8 billion years of its existence, the Universe really expanded with a deceleration, and then, for more than 7 billion years, there has been an acceleration. And then it will only intensify, and for an indefinitely long time.

Scientists estimate that "dark energy" accounts for about 67 percent of the world's energy, while the so-called dark or invisible matter - 30 percent and the usual visible - all stars and planets - only 3 percent. And so a team of astronomers from Yonsei University, together with colleagues from the University of Lyon and KASI, took aim at the formed picture of the world. After analyzing large databases, the scientists stated that astrophysicists made the conclusion about the expansion of the Universe on the basis of a serious measurement error. This means that there is no need to introduce the concept of "dark energy". It turns out that science has been looking for a phenomenon for more than 20 years, which in fact does not exist at all. By the way, in this case, Einstein's constant is still superfluous.

Note that this is not the first attack on "dark energy". And earlier there were works where its existence was questioned. But the latest study, in the opinion of many experts, seems to be the most reasoned. "Our results show that the" dark energy "hypothesis based on supernova cosmology, awarded Nobel Prize, may be based on an unreliable and simply erroneous assumption, "- said study leader Yong Wook Lee. However, critics of this work point to its weakness: a small database, on the basis of which revolutionary conclusions are made.

Today, there are several experimental installations in the world that try to catch "dark energy", but it has never fallen into the grid. However, the scientists themselves admit that they are looking almost blindly, because they still do not know exactly what to catch. What is the material carrier of this phenomenon. Candidates are considered to be WIMP particles that have appeared in theorists' formulas. But so far the theory has not been confirmed by experiment.

The term "dark energy" originated at the end of the 20th century. It is associated with observations of supernovae, which from time to time flare up brightly in the sky. These stars are used to determine cosmological distances. In 1998, scientists in the United States and Australia almost simultaneously discovered one oddity: the most distant supernovae do not shine as brightly as the formulas prescribed. This means that they are located farther from us than they should be if the Universe expanded in the field of ordinary gravitational forces. Hence the sensational conclusion: with a certainty of 99 percent, it can be argued that there must be some additional energy in the Universe that is opposed to gravity. This is how "dark energy" appeared.

In astronomy, a satellite is a body that revolves around a larger body and is held by its gravity. The Moon is the Earth's satellite. The Earth is a satellite of the Sun. All planets 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 the 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 so big and close!

It is visible to the naked eye better than any planet through a telescope. Telescopic observations and large photographs show that its beautiful surface is uneven and extremely complex. An active study of the natural satellite of the Earth began in 1959, when space probes and automatic interplanetary stations that delivered samples of lunar rocks were launched in our country and in the United States towards the Moon for its comprehensive study. And to this day, spacecraft bring a lot of information for the work of selenologists (scientists who study the moon). Our satellite conceals many mysteries. For a long time, people did not see its reverse side until 1959, when the automatic station "Luna-3" photographed the invisible side of the lunar surface. Later, maps of the lunar surface were compiled on the basis of images obtained with the help of the domestic probe "Zond-3" and the American spacecraft "Lunar Orbiter". Lunar automatic stations flights and landings lunar expeditions helped to answer a number of unclear questions that worried astronomers. But, in turn, they set new challenges for astronomers.

The sun, moon, large planets, their rather large satellites and the overwhelming number of distant stars have the shape of a ball. In all cases, the reason for this is gravity. The forces of gravity act on all bodies in the universe. Any mass attracts another mass to itself the stronger, the smaller the distance between them, and in no way can you change (strengthen or weaken) this attraction ....

The world of stone is diverse and amazing. In deserts, on mountain ranges, in caves, under water and on plains, stones processed by the forces of nature resemble Gothic temples and outlandish animals, harsh warriors and fantastic landscapes. Nature everywhere and in everything manifests its violent imagination. The stone chronicle of the planet was written over billions of years. It was created by streams of hot lava, dunes ...

All over our planet, among fields and meadows, forests and mountain ranges, blue spots of various sizes and shapes are scattered. These are lakes. Lakes appeared for various reasons. The wind blew out a depression, the water washed out the hollow, a glacier plowed out a hollow or a mountain avalanche dammed the river valley - that is why a reservoir was formed in such a depression in the relief. There are about ...

From time immemorial in Russia, they knew that there are ruinous places in which it is impossible to settle. The role of environmental inspectors was played by “knowledgeable people” - monks, schemniks, dowsers. Of course, they did not know anything about geological faults or underground drains, but they had their own professional signs. The benefits of civilization have gradually weaned us off responsive to changes in environment,…

The custom of measuring the time of a seven-day week came to us from Ancient Babylon and was associated with a change in the phases of the moon. The number "seven" was considered exceptional, sacred. At one time, ancient Babylonian astronomers discovered that, in addition to fixed stars, seven wandering luminaries are visible in the sky, which were called planets. Ancient Babylonian astronomers believed that every hour of the day is under the auspices of a certain planet….

The countdown of the signs of the zodiac along the ecliptic begins from the point of the vernal equinox - March 22. The ecliptic and the celestial equator intersect at two equinox points: spring and autumn. On these days all over the globe, the day is equal in duration to the night. Strictly speaking, this is not entirely correct, since due to displacements earth axis(precession) constellations and signs of the zodiac are not ...

I am dying - because I want to. Scatter, executioner, scatter my despicable ashes! Hello Universe, Sun! To the executioner He will scatter my thought throughout the Universe! I. Bunin The Renaissance era was marked not only by the flourishing of sciences and art, but also by the creative personalities... One of them is a scientist and philosopher, a master of logical proofs, who won disputes among professors in England, Germany, ...

Solar and lunar eclipses have been familiar to man since ancient times. When a person did not yet know why these phenomena were occurring, the extinction of the Sun in broad daylight caused him a panic. It is truly a mysterious and majestic sight. The bright sun shines on the blue sky and gradually sunlight begins to weaken. Damage appears at the right edge of the Sun. It is slowly increasing ...

But what if our star - the Sun - suddenly explodes into a supernova? Disappear by itself and erase us from the Universe forever? Scientists say that although this event is possible, its probability is very small. The star receives its energy by gradually converting hydrogen into helium, then into heavier elements (carbon, oxygen, neon and others) with the help of a chain ...

The largest planet is named after the supreme god Olympus. In terms of volume, Jupiter is 1310 times larger than the Earth, and 318 times larger in mass. In terms of distance from the Sun, Jupiter is in fifth place, and in terms of brightness, it occupies fourth place in the sky after the Sun, Moon and Venus. A telescope shows a planet compressed at the poles with a noticeable row ...

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

The first thing to be dealt with is what is our satellite? The answer is unexpected: although the Moon is considered a satellite, it is technically as complete a planet as the Earth. It is large - 3476 kilometers across at the equator - and weighs 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-fledged participant in the Moon-Earth gravitational system.

Another such tandem in the solar system is known, and Charon. Although the entire mass of our satellite is slightly more than a hundredth of the mass of the Earth, the Moon does not revolve around the Earth itself - they have common center masses. And the closeness of a satellite to us gives rise to another interesting effect, tidal capture. Because of him, the Moon is always turned to the Earth by the same side.

Moreover, from the inside, the Moon is arranged like a full-fledged planet - it has a crust, a mantle and even a core, and in the distant past, volcanoes existed on it. However, nothing remained 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, which furrowed it, leaving craters. Some of the blows were so strong that they broke through her bark right down to her mantle. The pits from such collisions formed lunar seas, dark spots on the moon, which are easily distinguishable from. Moreover, they are present exclusively at visible side... Why? We will talk about this further.

Among cosmic bodies, the Moon affects the Earth the most - except, perhaps, the Sun. Lunar tides, which regularly raise the water level in the world's oceans, are the most obvious, but not the strongest, impact of the satellite. So, gradually moving away from the Earth, the Moon slows down the rotation of the planet - the solar day has grown from the original 5 to the modern 24 hours. And the satellite also serves as a natural barrier against hundreds of meteorites and asteroids, intercepting them on their way to 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 flares and auroras on the lunar surface, not all of which can be explained. It turns out that our satellite hides much more than is visible on the surface - let's figure out the secrets of the Moon together!

Topographic map of the Moon

Moon characteristics

The scientific study of the moon is now over 2,200 years old. The movement of a satellite in the sky of the Earth, the phases and distance from it to the Earth were described in detail by the ancient Greeks - and internal structure The moon and its history are explored to this day by spacecraft. Nevertheless, centuries of work by philosophers and then by physicists and mathematicians have provided very accurate data on how our moon looks and moves, and why it is exactly like that. All information about a satellite can be divided into several categories, mutually flowing 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 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, which is 390 times farther from 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 the movement of our satellite resembles a spiral, and even difficult. The axis of the lunar orbit fluctuates, the Moon itself periodically approaches and moves away, and on a global scale it completely flies away from the Earth. The same fluctuations lead to the fact that the visible side of the Moon is not the same hemisphere of the satellite, but different parts of it, which alternately rotate towards the Earth due to the "rocking" of the satellite in orbit. These movements of the Moon in longitude and latitude are called librations, and they allow you to look behind the reverse side of our satellite long before the first flyby by spacecraft. The moon rotates 7.5 degrees from east to west, and 6.5 degrees from north to south. Therefore, from the Earth, you can easily see both poles of the Moon.

The specific orbital characteristics of the Moon are useful not only for astronomers and astronauts - for example, photographers especially value 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 the ideal 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 4.5 thousand kilometers from the center of the Earth.
The sidereal month - the full passage of the Moon in its orbit - takes 27.3 days. However, for a complete revolution around the Earth and a change lunar phases it takes 2.2 days more - after all, during the time that the Moon is in its orbit, the Earth flies through the thirteenth part of its own orbit around the Sun!
The Moon is in tidal grip of the Earth - it rotates around its axis at the same speed as around the Earth. Because of this, the Moon is constantly turned to the Earth by 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 an earth month.
In 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 closes it back. The changes in the illumination of the Moon, visible from the Earth, are called it. During the new moon, the satellite is not visible in the sky, in the phase of the young moon, its thin crescent appears, reminiscent of the curl of the letter "P", in the first quarter the moon is exactly half illuminated, and during the full moon it is noticeably best of all. Further phases - the second quarter and the old moon - occur in reverse order.

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

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

Physical parameters of the moon and its composition

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

The Apollo 11 crew brought 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 proceeded from their ignorance in space affairs. The American flag, which, according to the assurances of the conspiracy theorists, “could not fly in the airless space of the moon,” is actually solid and static - it was specially reinforced with solid threads. This was done specifically in order to take beautiful pictures - the sagging canvas is not so spectacular.

Many color and shape distortions in the reflections on the helmets of the spacesuits in which the fake was sought were due to gold plating on the UV-resistant glass. Soviet cosmonauts who watched the broadcast of the astronauts' landing in real time, also confirmed the accuracy of what is 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 space station LRO (English "Lunar Reconnaissance Orbiter", Lunar Orbital Probe) not only delivered the most detailed images of the Moon in history, but also proved the presence on it a large number frozen water. He also put an end to the discussion about whether people were on the moon by filming the traces of the Apollo team from the low orbit of the moon. The device was equipped with equipment from several countries of the world, including Russia.

Since new space states like China and private companies are joining the exploration of the moon, fresh data comes in every day. We have collected the main parameters of our satellite:

The lunar surface area occupies 37.9x10 6 square kilometers - about 0.07% of the entire Earth's area. Incredibly, this is only 20% larger than the area of all human-populated 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 falls on regolith - a small crumb of stone created by cosmic erosion and meteorite impacts, the density of which is lower than that of ordinary 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. Acceleration of free fall on it is 1.63 m / s 2 - only 16.5 percent of the entire gravity of the Earth. The astronauts' jumps on the moon were very high, even though their suits weighed 35.4 kilograms - almost like knightly armor! At the same time, they were still restrained: falling in a vacuum was quite dangerous. Below is a video of the astronaut's jumps from the live broadcast.

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

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

How did the moon form?

The study of the minerals of the moon 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 trap the 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 length of day and night intensifies 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, the Moon is believed to be the product of a collision of a large planetary embryo, Theia, with 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 Earth's surface matter, was thrown by inertia into orbit, where it remained in the form of the Moon.

This is proved by the aforementioned deficiency of iron and other metals on the Moon - by the time Theia pulled out a piece of terrestrial matter, most of the heavy elements of our planet were pulled inward by gravity, to the core. This clash affected further development Earth - it began to rotate faster, and its axis of rotation tilted, which made it possible to change the seasons.

Further, the Moon developed as an ordinary planet - it formed an iron core, mantle, crust, lithospheric plates and even its own atmosphere. However, the low mass and the composition poor in heavy elements led to the fact that the bowels of our satellite quickly cooled down, and the atmosphere evaporated from the high temperature and lack of magnetic field... However, some processes are still taking place inside - moonquakes sometimes occur due to movements in the lithosphere of the Moon. They represent one of the main dangers for the future colonizers of the Moon: their scope reaches 5 and a half points on the Richter scale, and they last much longer than the earth's - there is no ocean that can absorb the momentum of the earth's interior.

The main chemical elements on the moon, these 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 things, a high proportion of meteorite impurities and traces of the effects of cosmic radiation. The ozone layer of the Earth was formed 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 face of our planet.

The future of the moon

The moon is the first space body after Mars, which claims to be the primary human colonization. In a sense, the Moon has already been mastered - the USSR and the USA have 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 in 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 receding of the Moon due to tidal acceleration. It happens quite slowly - the satellite flies 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 the lunar month - 29-30 days.

However, the Moon's removal 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 able to completely crash into it. At 12-20 thousand kilometers from the Earth, its Roche lobe begins - the gravitational limit at which the satellite of any planet can maintain a solid shape. Therefore, the Moon on approach will be torn into millions of small fragments. Some of them will fall to Earth, setting up a bombardment thousands of times more powerful than nuclear, and the rest will form a ring around the planet. However, it will not be so bright - the rings of the gas giants are made 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 pose a problem for astronomers of the future - if, of course, by that time someone will remain on the planet.

Colonization of the Moon

However, all this will happen in billions of years. Until then, humanity considers the moon as the first potential object for space colonization. However, what exactly is meant by "conquering the moon"? Now we will look at the nearest prospects together.

Many people imagine the colonization of space is like the colonization of the Earth during the New Age - searching for valuable resources, obtaining them, and then bringing them back home. However, this does not apply to space - in the next couple of hundred years, shipping a kilogram of gold even from the nearest asteroid will cost more than mining it from the most difficult 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, 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, the same Mars. the main problem cosmonautics today are restrictions on the weight of spacecraft. To launch, you have to build monstrous structures that need tons of fuel - after all, you need to overcome not only the Earth's gravity, but also the atmosphere! And if this is an interplanetary ship, then you also need to refuel it. This seriously constrains designers, forcing them to prefer parsimony to functionality.

The moon is much better suited for a launch pad for spaceships. The lack of an atmosphere and the low speed to overcome the moon's gravity - 2.38 km / s versus 11.2 km / s from Earth - make launches much easier. And the satellite's mineral deposits make it possible to save on fuel weight - a stone around the neck of astronautics, which takes up a significant proportion of the mass of any vehicle. If we expand the production of rocket fuel on the moon, it will be possible to launch large and complex spaceships collected from parts delivered from Earth. And assembly on the moon will be much easier than on near-earth orbit- and much more reliable.

The technologies existing today allow, if not completely, then partially, to implement this project. However, any steps in this direction require risk. An enormous investment of money will require research for the required fossils, 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 as the people of the whole world to achieve such a valuable unity. For in the unity of humanity lies the true strength of the Earth.

The moon is the only natural satellite in Earth's orbit and the most studied extraterrestrial body. It is unique in many ways: its brightness in the sky, tidal effect on our planet, poorly studied back side and the possibility of colonizing its surface. In this article, we will describe in detail and tell you a lot interesting facts about the closest neighbor of our planet.

Our neighbor

Why is it called a satellite of the Earth?

The definition of the concept says that this is a natural or artificial object that in outer space moves in a certain orbit around another object under the action of gravitational forces.

The fact that the moon is a satellite was still proved by the ancient Greeks. Famous ancient astronomers and physicists such as Aristarchus, Hipparchus, Archimedes calculated the size of the brightest object in the night sky. You can calculate its orbit and distance to our planet. The invention of the telescope, and later on the spacecraft, helped to make sure of the correctness of the judgments and calculations of the ancient Greek researchers.

In addition to revolving around our planet, the Moon has a direct impact on the waters of the world's oceans. This phenomenon is called tidal interaction, and it once again confirms the fact that the Moon is a natural satellite of the Earth.

Research history

The movements of the moon in the sky were observed by astronomers Ancient World... In the 2nd century BC, its size and distance to the Earth were already calculated. Medieval explorers with the help of a telescope were able to identify individual areas of the relief and draw up the first lunar map. In the 19th century, the first images of the lunar surface appeared, from which a photographic atlas was compiled.

The invention of spacecraft helped expand knowledge of the moon. Beginning in 1958, Soviet and American researchers launched several dozen automatic and manned vehicles towards it, artificial satellites and lunar rovers, which got its name in history known as the Moon Race. One of major events in the history of human civilization, the first people landed on its surface - American astronauts Neil Armstrong and Buzz Aldrin. It happened on July 20, 1969. Five more moon landings took place between November 1969 and December 1972.

Currently, the Moon is being explored by American and Chinese stations in a circumlunar orbit, as well as those that have descended to the surface of the far side of the Earth's satellite.

Characteristics

Basic physical parameters:

Weight - 7.35 * 10 22 kg.
The average diameter is 3.5 thousand km.
Surface area - 3.79 * 10 7 sq. km.
The average density is 3.35 g / cc. cm.
Free fall acceleration near the equator is 1.62 m / s 2.

The moon has a typical structure for solid objects in the solar system: crust, mantle and core. Its surface is represented by regolith - a mixture of dust particles of various diameters and fragments of lunar rocks, minerals and meteorites. Thickness lunar soil ranges from a couple of centimeters to several tens of meters. Further, to a depth of 50 km, lies a crust containing a high percentage of iron, aluminum and silicon. The mantle, which has a three-layer structure, is presented different kinds silicates. Under it is an iron-nickel core, which occupies 20% of the entire mass of the Earth's satellite.

The Moon has practically no atmosphere. It contains only residual traces of hydrogen and some inert gases. Due to the extreme rarefaction of the gas envelope, the satellite surface is constantly exposed to sharp temperature changes: from + 117 ° С during the day to -173 ° С at night.

Orbit

The average radius of the Moon's orbit is 1.73 thousand km. Moving at a speed of 1.023 km / s, the satellite makes a complete revolution around the Earth in 27 days and 7 hours. This period is called the sidereal or lunar month. The orbital path has an elliptical shape (eccentricity - 0.055), and the trajectory of the earth's satellite itself resembles an unwinding spiral. The angle of inclination of the axis to the orbital plane ranges from 4.5 ° to 5 °.

Influence

The moon and the earth exert a strong gravitational influence on each other. The changes caused by the gravity of a satellite in the world's oceans are called tidal forces. Depending on the relative position of the Earth and its satellite, the height of the sea level changes, which is called the ebb and flow. The maximum amplitude of tidal waves is observed in the Canadian Gulf of Fundy, where they reach a height of 18 meters.

Future

The moon is one of the main contenders for the foundation human colony... It is considered as a transshipment base on the way from Earth to other space objects. It is much easier for interplanetary ships to take off from its surface due to the weak gravitational force and the rarefied atmosphere, and in the subsurface layers there are large deposits of minerals considered as a fuel resource. Roscosmos plans to launch a mission to explore the lunar surface in the period from 2021 to 2040.

The distant future of the Moon as a satellite of our planet is not so rosy. Due to tidal acceleration, it annually moves away from the Earth by 0.38 cm. This slows down the rotation of the blue planet, lengthening the day on it. However, after a gradual and long process of removal, the satellite will begin to return rather quickly, having approached the Earth at the minimum possible distance of 12 thousand km. Gravitational forces will tear it apart into tiny fragments that form a whole ring system around the Earth, similar to the rings of other planets of the solar system.

From Earth, you can see only one side of the moon's surface, or rather only 59%. This is due to the mutual gravitational influence of the planet and its satellite. However, the reverse side of the Moon cannot be considered dark - it receives as much light as the part facing the earthlings. The relief of the reverse side is more dotted with craters, and there are only two lunar seas on it.
According to scientists, the Moon was once part of the Earth. The fragment of the planet that formed the satellite was helped by a collision with a large space object- protoplanet Theia. It happened about 4.6 billion years ago - at the dawn of the formation of the planets of the solar system. Thus, the Moon is almost as old as the Earth.
An unusual gift can be the purchase of an entire acre on a satellite of the Earth. The sale of certificates of ownership of the lunar site is carried out by the Lunar Embassy, organized by the enterprising American Dennis Hope in 1980. In addition to the certificate, the lucky owners of 40 lunar acres can receive a lunar passport, a map and a certificate of ownership. Naturally, all these documents have no legal force and are just a souvenir.
January 3, 2019 at back side satellite of the Earth for the first time landed a mobile lunar rover belonging to the China National Space Administration.
One of unique features lunar relief is considered to be seas covered with volcanic basalt. In total, on the visible side of the moon, there are 1 ocean, 20 seas, 11 bays, 18 lakes and 3 swamps. There are also mountains on the satellite, named after similar mountain formations on Earth.