Home Roses The structure of the moon of the satellite of the earth. Description of the moon. Lunar surface - explanation for children

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The structure of the moon of the satellite of the earth. Description of the moon. Lunar surface - explanation for children

The average distance between the centers of the Earth and the Moon is 384 467 km (0.002 57 AU, ~ 30 Earth diameters).

The apparent magnitude of the full moon in the earth's sky is −12.71m. The illumination created by the full moon near the surface of the Earth in clear weather is 0.25 - 1 lux.

The moon is the only astronomical object outside the Earth that has been visited by humans.

Name

The word moon goes back to prasslav. * luna< пра-и.е. *louksnā́ «светлая» (ж. р. прилагательного *louksnós), к этой же индоевропейской форме восходит и лат. lūna «луна». Греки называли спутник Земли Селеной (др.-греч. Σελήνη), древние египтяне - Ях (Иях).

Moon as a celestial body

Orbit

Since ancient times, people have tried to describe and explain the movement of the moon. Over time, more and more accurate theories appeared.

The basis of modern calculations is Brown's theory. Created at the turn of the XIX-XX centuries, it described the movement of the moon with the accuracy of the measuring instruments of that time. At the same time, more than 1400 terms (coefficients and arguments for trigonometric functions) were used in the calculation.

Modern science can calculate the motion of the moon and test those calculations with even greater precision. Using laser ranging methods, the distance to the moon is measured with an error of several centimeters. Not only measurements, but also theoretical predictions of the position of the moon have such an accuracy; for such calculations, expressions with tens of thousands of terms are used and there is no limit to their number if even higher precision is required.

As a first approximation, we can assume that the Moon is moving in an elliptical orbit with an eccentricity of 0.0549 and a semi-major axis of 384 399 km. The actual motion of the moon is quite complex, and many factors must be taken into account when calculating it, for example, the flattening of the earth and the strong influence of the sun, which attracts the moon 2.2 times stronger than the earth. More precisely, the movement of the Moon around the Earth can be represented as a combination of several movements:

revolution around the Earth in an elliptical orbit with a period of 27.32166 days, this is the so-called sidereal month (that is, the movement is measured relative to the stars);

rotation of the plane of the lunar orbit: its nodes (points of intersection of the orbit with the ecliptic) are shifted to the west, making a complete revolution in 18.6 years. This movement is precessional;

rotation of the major axis of the lunar orbit (line of apses) with a period of 8.8 years (occurs in the opposite direction than the above movement of the nodes, that is, the longitude of the perigee increases);

periodic change in the inclination of the lunar orbit in relation to the ecliptic from 4 ° 59 ′ to 5 ° 19 ′;

periodic change in the size of the lunar orbit: perigee from 356.41 to 369.96 thousand km, apogee from 404.18 to 406.74 thousand km;

the gradual removal of the Moon from the Earth due to tidal acceleration (by about 4 cm per year), thus, its orbit is a slowly unwinding spiral.

General structure

The moon consists of the crust, the upper mantle (asthenosphere), the middle mantle, the lower mantle, and the core. The atmosphere is practically absent. The lunar surface is covered with so-called regolith - a mixture of fine dust and rocky debris formed as a result of collisions of meteorites with the lunar surface. Impact-explosive processes accompanying meteorite bombardment contribute to loosening and mixing of the soil, simultaneously sintering and compacting soil particles. The thickness of the regolith layer ranges from fractions of a meter to tens of meters.

The thickness of the lunar crust varies widely from 0 to 105 km. According to data from the gravity reconnaissance satellites GRAIL, the thickness of the lunar crust is greater in the hemisphere that faces the Earth.

Conditions on the lunar surface

The atmosphere of the moon is extremely rarefied. When the surface is not illuminated by the Sun, the gas content above it does not exceed 2.0 · 10 5 particles / cm³ (for the Earth this figure is 2.7 · 10 19 particles / cm³), and after sunrise it increases by two orders of magnitude due to soil degassing ... The thinness of the atmosphere leads to a high temperature drop on the lunar surface (from −160 ° C to +120 ° C), depending on the illumination; the temperature of rocks at a depth of 1 m is constant and equal to -35 ° C. Due to the virtual absence of an atmosphere, the sky on the moon is always black, with stars, even when the sun is above the horizon.

The earth's disk hangs almost motionless in the sky of the moon. The reasons for the small monthly fluctuations of the Earth in height above the lunar horizon and in azimuth (approximately 7 °) are the same as those of librations. The angular size of the Earth when observed from the Moon is 3.7 times larger than the lunar when viewed from the Earth, and the area of the celestial sphere covered by the Earth is 13.5 times larger than that covered by the Moon. The degree of illumination of the Earth, visible from the Moon, is the opposite of the lunar phases visible on the Earth: at a full moon, an unlit part of the Earth is visible from the Moon, and vice versa. Illumination by reflected light from Earth is about 50 times stronger than illumination by moonlight on Earth, with Earth's maximum apparent magnitude on the Moon being approximately −16 m.

Gravitational field

The gravitational potential of the Moon is traditionally written as the sum of three terms:

where δ W- tidal potential, Q- centrifugal potential, V- the potential of attraction. The attraction potential is usually decomposed into zonal, sectoral and tesseral harmonics:

where P n m- the associated Legendre polynomial, G- gravitational constant, M- the mass of the moon, λ and θ - longitude and latitude.

Ebb and flow

The moon's gravitational influence has some interesting effects on Earth. The most famous of these is the ebb and flow of the sea. On opposite sides of the Earth, two bulges are formed (in the first approximation) - on the side facing the Moon and on the opposite to it. In the world's oceans, this effect is much more pronounced than in the solid crust (the water bulge is greater). The amplitude of the tides (the difference in high and low tide levels) in the open spaces of the ocean is small and amounts to 30-40 cm. However, near the coast, due to the onslaught of the tidal wave on the solid bottom, the tidal wave increases the height in the same way as ordinary wind waves of the surf. Taking into account the direction of the Moon's revolution around the Earth, it is possible to form a picture of the following of a tidal wave in the ocean. The eastern coasts of the continents are more susceptible to strong tides. The maximum amplitude of the tidal wave on Earth is observed in the Bay of Fundy in Canada and is 18 meters.

Although for the earth the magnitude of the sun's gravitational force is almost 200 times greater than that of the moon, the tidal forces generated by the moon are almost twice as large as those generated by the sun. This is due to the fact that tidal forces depend not only on the magnitude of the gravitational field, but also on the degree of its inhomogeneity. With increasing distance from the source of the field, the inhomogeneity decreases faster than the magnitude of the field itself. Since the Sun is almost 400 times farther from the Earth than the Moon, the tidal forces caused by solar attraction are weaker.

A magnetic field

It is believed that tectonic activity is the source of the planet's magnetic fields. For example, the Earth's field is created by the movement of molten metal in the core, y - by the consequences of past activity.

"Luna-1" in 1959 established the absence of a uniform magnetic field on the moon. The results of research by scientists at the Massachusetts Institute of Technology support the hypothesis that it had a liquid core. This fits into the framework of the most popular hypothesis of the origin of the Moon - the collision of the Earth about 4.5 billion years ago with a space body the size of Mars "knocked out" a huge piece of molten matter from the Earth, which later turned into the Moon. Experimentally, it was possible to prove that at the early stage of its existence, the Moon had a magnetic field similar to that of the Earth.

Observing the Moon from Earth

The relationship between the phases of the moon and its position relative to the sun and the earth. The angle by which the Moon will rotate from the end of the sidereal month to the end of the synodic month is highlighted in green.

In the southern hemisphere, the moon is inverted, as in this Australian image.

The angular diameter of the Moon is very close to that of the Sun and is about half a degree. The moon looks white and yellow from Earth, although it reflects only 7% of the incident sunlight (roughly like charcoal). Since the Moon does not shine by itself, but only reflects sunlight, only the part of the lunar surface illuminated by the Sun is visible from the Earth (in the phases of the Moon close to the new moon, that is, at the beginning of the first quarter and at the end of the last quarter, with a very narrow crescent, one can observe “ ash light of the Moon "- weak illumination of it by the rays of the Sun, reflected from the Earth). The moon revolves in an orbit around the earth, and thus the angle between the earth, the moon and the sun changes; we observe this phenomenon as a cycle of lunar phases. The time period between successive new moons averages 29.5 days (709 hours) and is called a synodic month. The fact that the duration of the synodic month is longer than the sidereal month is explained by the movement of the Earth around the Sun: when the Moon, relative to the stars, makes a full revolution around the Earth, the Earth has already passed 1/13 of its orbit, and so that the Moon again finds itself between the Earth and the Sun, she needs an additional two days.

Lunar librations

Although the Moon rotates around its axis, it always faces the Earth with the same side, that is, the Moon's rotation around the Earth and rotation around its own axis is synchronized. This synchronization is caused by the friction of the tides that the Earth produced in the lunar shell. According to the laws of mechanics, the Moon is oriented in the Earth's gravitational field so that the semi-major axis of the lunar ellipsoid is directed to the Earth.

The phenomenon of libration, discovered by Galileo Galilei in 1635, makes it possible to observe about 59% of the lunar surface. The fact is that the Moon revolves around the Earth with a variable angular velocity due to the eccentricity of the lunar orbit (near perigee it moves faster, near the apogee more slowly), while the rotation of the satellite around its own axis is uniform. This allows you to see from the Earth the western and eastern edges of the far side of the Moon (optical libration in longitude). In addition, due to the inclination of the Moon's rotation axis to the plane of the Earth's orbit, one can see the northern and southern edges of the far side of the Moon from the Earth (optical libration in latitude). There is also physical libration due to the oscillation of the satellite around the equilibrium position in connection with the displaced center of gravity, as well as in connection with the action of tidal forces from the Earth. This physical libration has a magnitude of 0.02 ° in longitude with a period of 1 year and 0.04 ° in latitude with a period of 6 years.

Due to refraction in the Earth's atmosphere, when observing the Moon low above the horizon, its disk is flattened.

The time (1.255 seconds) it takes for light from the Earth to reach the Moon. The drawing is drawn to scale.

Due to the unevenness of the relief on the surface of the Moon, Bailey's rosary can be observed during a total solar eclipse. When, on the contrary, the Moon falls into the Earth's shadow, another optical effect can be observed: it turns red, being illuminated by light scattered in the Earth's atmosphere.

Selenology

Radial gravity anomaly on the lunar surface.

Due to its size and composition, the Moon is sometimes referred to as the terrestrial planets along with Mercury, Venus, Earth and Mars. By studying the geological structure of the Moon, you can learn a lot about the structure and development of the Earth.

The thickness of the lunar crust is on average 68 km, varying from 0 km under the lunar sea of Crises to 107 km in the northern part of the Korolev crater on the reverse side. Beneath the crust is a mantle and possibly a small iron sulphide core (about 340 km in radius and 2% of the Moon's mass). It is curious that the center of mass of the Moon is located about 2 km from the geometric center towards the Earth. According to the results of the Kaguya mission, it was found that in the Moscow Sea, the thickness of the crust is the smallest for the entire Moon - almost 0 meters under a layer of basalt lava 600 meters thick.

Measurements of the speed of the satellites "Lunar Orbiter" made it possible to create a gravitational map of the moon. With its help, unique lunar objects were discovered, called mascons (from the English mass concentration) - these are masses of matter of increased density.

The Moon does not have a magnetic field, although some of the rocks on its surface show residual magnetism, which indicates the possibility of the existence of a magnetic field of the Moon in the early stages of development.

With no atmosphere or magnetic field, the lunar surface is directly exposed to the solar wind. For 4 billion years, hydrogen ions from the solar wind were introduced into the lunar regolith. Thus, the samples of regolith delivered by the Apollo missions proved to be very valuable for the study of the solar wind.

In February 2012, American astronomers discovered several geological formations on the far side of the moon. This indicates that lunar tectonic processes continued for at least another 950 million years after the supposed date of the geological "death" of the Moon.

Caves

The Japanese Kaguya probe discovered a hole in the lunar surface near the Marius Hills volcanic plateau, presumably leading into a tunnel below the surface. The hole is about 65 meters in diameter and is believed to be 80 meters deep.

Scientists believe that such tunnels are formed by solidification of flows of molten rock, where lava has frozen in the center. These processes took place during the period of volcanic activity on the Moon. Confirmation of this theory is the presence of winding grooves on the surface of the satellite.

Such tunnels can serve for colonization, thanks to the protection from solar radiation and the enclosure of space, in which it is easier to maintain life support conditions.

There are similar holes on Mars.

Seismology

The four seismographs left on the moon by the Apollo 12, Apollo 14, Apollo 15 and Apollo 16 expeditions showed the presence of seismic activity. Based on the latest calculations of scientists, the lunar core consists mainly of red-hot iron. Due to the lack of water, fluctuations of the lunar surface are long in time, can last more than an hour.

Moonquakes can be divided into four groups:

tidal, occurring twice a month, caused by the influence of the tidal forces of the Sun and Earth;
tectonic - irregular, caused by movements in the soil of the Moon;
meteorite - due to falling;
thermal - they are caused by the sharp heating of the lunar surface with the rising of the Sun.

Tectonic moonquakes pose the greatest danger to possible habitable stations. For 5 years of research, NASA seismographs have registered 28 such moonquakes. Some of them reach 5.5 on the Richter scale and last more than 10 minutes. For comparison, on Earth, such earthquakes last no more than two minutes.

Water on the moon

For the first time, information about the discovery of water on the Moon was published in 1978 by Soviet researchers in the journal Geochemistry. The fact was established as a result of analysis of samples delivered by Luna-24 in 1976. The percentage of water found in the sample was 0.1.

In July 2008, a group of American geologists from the Carnegie Institution and Brown University discovered traces of water in the lunar soil samples, which were released in large quantities from the bowels of the satellite in the early stages of its existence. Most of this water later evaporated into space.

Russian scientists, with the help of the LEND device they created, installed on the LRO probe, have identified the regions of the Moon that are richest in hydrogen. Based on this data, NASA selected a site for the LCROSS bombardment of the moon. After the experiment, on November 13, 2009, NASA reported the discovery of water in the form of ice in the Cabeus crater near the South Pole.

According to the data transmitted by the Mini-SAR radar installed on the Indian lunar apparatus Chandrayan-1, at least 600 million tons of water have been found in the North Pole region, most of which is in the form of ice blocks resting on the bottom of lunar craters. In total, water has been found in more than 40 craters, the diameter of which varies from 2 to 15 km. Now scientists no longer have any doubts that the ice found is precisely water ice.

Lunar rock chemistry

Thorium concentration map on the lunar surface according to Lunar Prospector data.

The composition of the lunar soil differs significantly in the marine and continental regions of the Moon. Lunar rocks are depleted in iron, water and volatiles.

There is a metal core in the bowels of the moon! This is the conclusion reached by Rene Weber of NASA's Marshall Space Flight Center and Rafael Garcia of the University of Toulouse after re-examining the data obtained during the Apollo lunar mission in the late 60s and early 70s. Perhaps the discovery will shed new light on the evolution of the Earth's satellite.

As part of the Apollo space program, four seismometers were delivered to the moon, which recorded the seismic activity of a celestial body until 1977. It turned out that seismic shocks on the Moon occur much less frequently than on Earth. At the same time, since the surface of the earth's satellite is dotted with craters left over from collisions with small cosmic bodies, this distorts the signals of the instruments and makes the oscillations of the lunar crust not so noticeable.

For a long time, information obtained from the moon through seismic sensors was considered practically useless for scientists. However, over the past forty years, the methods for analyzing seismic data have changed significantly. In addition, Weber and Garcia were able to account for the "error" arising from the craters. As a result, they came to the conclusion that the Moon, like the Earth, has a red-hot metal core. Its diameter is about 330-360 kilometers, it is surrounded by a partially molten shell with a diameter of about 480 kilometers. Inside the core, in turn, is a solid iron core with a diameter of about 240 kilometers.

“We applied robust seismological techniques to process this dataset, resulting in the first direct evidence of a lunar core,” said cosmologist René Weber.

The researchers also analyzed the seismograms by processing the data in groups, which made it possible to determine the source of the seismic activity. Having determined the trajectories of seismic waves and the features of their reflection from the inner layers of the moon, they were able to identify the composition and structure of the layers of the lunar core at different depths.

Scientists believe that due to the large amount of iron in the interior, the moon has a powerful magnetic field. Although the lunar core is in many ways similar to that of the earth, their structure is still different. As we know, the earth's core has a solid inner and outer liquid layer. And in the core of the Moon there is also a solid third layer, bordering between the mantle and the outer liquid nuclear envelope.

The moon is believed by astrophysicists to have formed about 4.5 billion years ago as a result of the collision of the Earth with a large space object the size of the planet Mars. Hypothetically, this shock "knocked out" from the Earth a piece consisting of the crust of the molten mantle, which later turned into the Moon. Moreover, studies carried out at the Kola superdeep well have established that the composition of the rocks of the peninsula is almost 90 percent the same as that of the lunar rocks. It turns out that this happened in the place where the layers of the crust were located, which later made up the Kola Peninsula.

Until recently, it was believed that the Moon is a "cold" celestial body, but the mystery for scientists was the presence of a weak (residual) magnetic field on it. The fact is that, as scientific theories say, tectonic activity is its source in planets. For example, on the Earth, it is created by the movement of molten metal in the core.

In 1959, it was found that the moon's magnetic field is inhomogeneous. As studies by scientists from the Massachusetts Institute of Technology have shown, the Moon had a liquid core at an early stage of its existence, and its magnetic field was similar to that of the Earth.

Now this phenomenon seems to be clarified. In addition, since the mantle of the Moon, apparently, is also red-hot and convection of matter occurs in it (for more details, see the article "Volcanoes - the level of anxiety is rising"), then our satellite may have volcanic activity. Indeed, the Japanese probe Kaguya discovered on the surface of the moon, not far from the Marius Hills plateau, a hole with a diameter of about 65 meters and a depth of about 80 meters. According to scientists, this may indicate the existence of tunnels on the Earth's satellite, paved by solidified flows of volcanic lava. This hypothesis is also confirmed by the presence of winding furrows of unknown origin on the satellite's surface.

The research results were presented at a recent conference of the American Astrophysical Union. Its participants noted that knowledge about the composition of the lunar core will also help to better understand how our Earth was formed and how it will evolve in the future.

Let's take a look at how the moon works.

The shape and composition of the moon

The moon, in contrast to the Earth, has a more regular spherical shape.

Its radius is approximately 1738 km, which is 0.272 of the earth's radius in the equatorial region.
The mass of the Moon is 81 times less than the mass of the Earth.
The attraction is 6 times less than that of the earth.

Because of this feature (too weak gravity), the Moon is not able to hold the atmosphere around itself (the atmosphere will be captured by the Earth), so projects to create an artificial atmosphere around the Moon are doomed to failure in advance. On the moon, it is only possible to create domes filled with breathing air.

The average distance from the Moon to the Earth is 384 400 km. The largest distance is 405,500 km, the smallest - 363,300 km. The part of the Moon invisible from Earth makes up 41 percent of the entire lunar surface. The temperature of the moon at the sunflower point is +130 degrees Celsius. The temperature of the moon on the night side is -160 degrees Celsius.

What the moon is made of

The lunar soil, which was brought to Earth by lunar expeditions, consists, as shown by the analysis, of a debris-dust layer called rigolite. This layer was formed on the rocky outcrops of the lunar surface under the influence of meteorite impacts (the moon is constantly bombarded by meteorites), the processes of heating and cooling, crushing, mixing and sintering.

And due to the fact that the solar wind affects the lunar soil, the rigolite is saturated with neutral gases. In general, lunar rocks have a twofold origin: some of them belong to the cosmos, while others have a lunar pedigree.

The lunar soil itself often bears traces of melting as a result of meteorite falls or is represented by volcanic (lava) rocks like earth's basalt, and the other part of rigolite is meteorites. There are a lot of them on the moon.

There are also breeds that are similar to terrestrial ones. Some rocks are enriched in potassium, phosphorus and rare earth metals. According to scientists, volcanic rocks are characteristic of the lunar seas, and similar to the terrestrial ones - for the lunar continents.

In general, the difference from terrestrial rocks is associated with the absence of water in the rocks, a low content of sodium and potassium, and an increased content of iron and titanium. In other words, the Moon is a mining paradise.

How the moon works

Lunar rocks are very ancient - their age is about 4 billion years, and the "youngest" (more than 3 billion years) were samples brought from the regions of the lunar seas.

The era of active volcanism on the Moon ended long ago.

Over time, the intensity of the meteorite bombardment of its surface also decreased. Due to this, over the past 2-3 billion years, the appearance of the lunar surface has not changed. (On Earth, under the influence of water and air, the ancient relief could not be preserved.)

However, even now there are moonquakes on the Moon (reminiscent of weak earthquakes), which are recorded by seismographs installed on the Moon by astronauts. The data from these devices made it possible to study the internal structure of the Moon, highlighting the crust (about 60 km thick), the mantle (up to 1000 km) and a core with a radius of about 750 km.

Lunar relief

Dry seas of the moon. They were called seas and oceans by terrestrial observers back in the era when it was believed that there are real seas with water on the moon. This was facilitated by the fact that people simply could not imagine their neighbor in another way, and the fact that, against the general background, the seas and oceans look like dark spots.

Only later it became clear that these seas and oceans are dry. And today we know that the color of the seas of the Moon, in contrast to the lunar "continents", is associated with the darker color of the rocks that compose them.

The sun's rays illuminate the lunar landscape unequally, they are more strongly reflected from the high and light "continents" and weaker - from the deeper and dark seas, therefore we see them on the surface of our satellite as spots.

Lunar seas occupy about 40 percent of the surface of the Earth-facing side of the planet. These lunar troughs are practically devoid of circuses, but there are many deep cracks and low smoothed shafts in them. Many lunar seas are surrounded by chains of lunar mountains.

Smaller depressions on the moon are called lakes and bays.

The names of the seas of the Moon show well how the Moon appeared to people: Sea of Rains, Sea of Tranquility, Sea of Crises, Ocean of Storms ... The first names of the moon seas were received in the 17th century. They were given to the lunar lowlands by the Italian astronomer Giovanni Batista Riccioli in 1651.

The largest seas of the Moon are the Sea of Cold, the Sea of Rains, the Sea of Fertility, and the Sea of Tranquility.

Lunar mountains

The mainland areas are represented by mountains and mountain ranges. It is very difficult to determine the height of the lunar mountains from Earth, since the satellite is turned to us on one side and we see a rather flat picture all the time. In addition, to determine the height, you need to have at least some kind of reference point.

On Earth, we calculate the height of mountains in relation to sea level. The moon is a dry planet. It has no water, and therefore no ocean level.

Therefore, the complex cartography of the Moon with the determination of the depth of the depressions and the height of the mountains is a task for future selenographers. Obviously, this work will require their presence on the planet itself. After all, images of the moon, even from satellites, do not provide accurate data on the height of the mountains. The first lunar mountains discovered by astronomers were named terrestrial - the Caucasus, the Apennines, the Alps, the Carpathians ...

Mountain ranges were formed as a result of meteorite bombing or volcanic activity on the moon itself. They vary greatly in height - from a couple of hundred meters to several kilometers. For example, the famous mountain range of the Apennines has peaks up to 6 km high.

The moon is also characterized by folded veins or mountain folds. They are not of meteoric origin, but were formed as a result of the subsidence and uplift of the lunar crust. Folded formations are observed only in areas adjacent to the seas or mountain systems.

Lunar craters

The surface of the moon is dotted with craters, or, as they are called, lunar circuses. Basically, lunar circuses were formed as a result of meteorites falling on it or the collision of the Moon with other large cosmic bodies. But not all lunar circuses are the result of the bombing of the moon.

There is a whole group of craters that have a different, volcanic origin. The craters are not as deep as seen from Earth. Basically, they have a depth of 10 m to 10 km, and the latter are not so common.

In general, scientists divide all circuses into five categories.

The first includes large single craters,
the other three types are distinguished by a lighter color of the adjacent areas and a later time of formation,
the fifth group of craters are circuses filled with lava (therefore, they are often called submerged).

Flooded craters are characterized by the fact that they do not have depressions and look smooth, as if they were closed by a lid on top. All craters have a rounded shape and specific grooves on the slopes. As a rule, young craters are surrounded by light rays. Sometimes they overlap existing ancient circuses.

Some craters are collected in chains. These circuses have a clear volcanic origin, because even with active bombardment by meteorites, such long and clear patterns on the moon could not form. Crater chains stretch for more than 150 km.

Cracks, faults and domes on the Moon

In addition to the seas, mountains and circuses on the moon, there are other interesting features of the relief. It is all riddled with cracks and furrows. It is believed that these grooves were formed as a result of the shearing of the lunar faults. Some appeared as a trail of bombardment by meteorites, when colliding with large objects.

And part is of lunar volcanic origin. Furrows stretch for considerable distances, sometimes not for one hundred kilometers. The depth of the furrows is relatively small - from 500 m to 1 km, and what is very characteristic - the width of the furrows does not change throughout its length.

An interesting feature of the lunar landscape is the faults. These are formations in the form of straight sheer walls, which can take up to several hundred kilometers. The most famous is the Straight Wall in the Sea of Clouds. Its length is about 100 km, and its depth is up to 400 m.

Another interesting detail of lunar geography is the domes. These are curved shields, which, according to scientists, were formed as a result of volcanic activity, that is, lava formations. Some of these domes have gaps that could appear when the lava subsided and voids formed inside the shields, like our karst ones. Ufologists often place secret alien factories in domes. There are not many domes on the moon, literally several dozen.

The moon is the most accessible body in, if you suddenly want to look at some space object with the naked eye. People were very interested in the history of the appearance of dark and light spots on its surface throughout the history of mankind. What caused the formation of these strange features?

Children's stories tell us about what is made of cheese. But, which is also true for other bodies in the solar system, the stone is a more realistic candidate for this. The lunar surface has dead volcanoes, impact craters, and solidified lava flows. Some of them can be seen without special devices.
Ancient scientists believed that the dark regions of the moon could be oceans. And that's why they called them in Latin "mare", which means "sea". These areas are indeed oceans in a sense. Instead of water, the lunar seas contain solidified lava. During the youth of the Moon, its crust was warmed up enough to form volcanoes. Although at the same time it quickly cooled and hardened. Lava could break through the crust when large enough asteroids fell on the moon.

On the lunar surface, there is a lot of evidence of the fall of such asteroids. At the beginning of the solar system's history, all planets and moons were affected by them. This was the so-called period of heavy bombing. Plate tectonics and surface erosion obscured much of the evidence from this period. In addition, the atmosphere helped burn some small meteorites, preventing them from reaching the surface. However, the Moon lacks all of these factors. Therefore, the history of the solar system remains unchanged on the lunar surface.

The thickness of the lunar crust is 60-100 km. The regolith on the surface can be shallow - up to 3 meters in the seas, and up to a depth of 20 meters at higher elevations.

Under the surface

Like the Earth, the Moon boasts the Earth's crust, mantle, and core. Deep within its bowels, the Moon may have a solid iron core surrounded by molten metal. The outer core of the Moon can be up to 500 km in size. However, the small inner core is only about 20 percent of the Moon, compared to 50 percent of other rocky bodies.

Most of the inner structure of the Moon consists of the lithosphere, which is about 1000 km thick. Since this area melted at the beginning of the Moon's evolution, it supplied magma to the lava plains on its surface. However, over time, the magma cooled and solidified, thereby ending volcanism on the Moon.

The moon is the second most dense body in the solar system after the satellite. The separation of its inner layers was probably caused by the crystallization of the magma ocean shortly after its formation.