Moon: description, characteristics, interesting facts. Moon mass Moon mass in tons

From time immemorial, the moon has been a constant satellite of our planet and the closest celestial body to it. Naturally, a person always wanted to go there. But how far is to fly there and how far is it?

The distance from the Earth to the Moon is theoretically measured from the center of the Moon to the center of the Earth. It is impossible to measure this distance by the usual methods used in everyday life. Therefore, the distance to the earth's satellite was calculated using trigonometric formulas.

Like the Sun, the Moon experiences constant motion in the earth's sky near the ecliptic. However, this movement is significantly different from the movement of the Sun. So the planes of the orbits of the Sun and the Moon differ by 5 degrees. It would seem that as a result of this, the trajectory of the moon in the earth's sky should be similar in general terms to the ecliptic, differing from it only in a shift of 5 degrees:

In this, the movement of the Moon resembles the movement of the Sun - from west to east, in the opposite direction to the daily rotation of the Earth. But in addition, the moon moves across the earth's sky much faster than the sun. This is due to the fact that the Earth revolves around the Sun in about 365 days (Earth year), and the Moon around the Earth in only 29 days (lunar month). This difference became the incentive to break down the ecliptic into 12 zodiacal constellations (in one month the Sun shifts along the ecliptic by 30 degrees). During the lunar month, there is a complete change in the phases of the moon:

In addition to the trajectory of the Moon, the factor of strong elongation of the orbit is also added. The eccentricity of the Moon's orbit is 0.05 (for comparison, for the Earth, this parameter is 0.017). The difference from the circular orbit of the Moon leads to the fact that the apparent diameter of the Moon is constantly changing from 29 to 32 arc minutes.

In a day, the Moon is shifted relative to the stars by 13 degrees, in an hour by about 0.5 degrees. Modern astronomers often use the lunar coverings to estimate the angular diameters of stars near the ecliptic.

What determines the movement of the moon

An important point in the theory of the motion of the moon is the fact that the orbit of the moon in outer space is not unchanging and stable. Due to the relatively small mass of the Moon, it is subject to constant disturbances from more massive objects in the Solar System (primarily the Sun and the Moon). In addition, the Moon's orbit is influenced by the flattening of the Sun and the gravitational fields of other planets in the Solar System. As a result, the magnitude of the eccentricity of the Moon's orbit fluctuates between 0.04 and 0.07 with a period of 9 years. The result of these changes was such a phenomenon as a supermoon. Supermoon is an astronomical phenomenon during which the full moon is several times larger in angular size than usual. So during the full moon on November 14, 2016, the moon was at a record close distance since 1948. In 1948, the Moon was 50 km closer than in 2016.

In addition, fluctuations in the inclination of the lunar orbit to the ecliptic are observed: by about 18 arc minutes every 19 years.

What is equal

Spacecraft will have to spend a lot of time on the flight to the earth's satellite. You cannot fly to the moon in a straight line - the planet will orbit away from the destination point, and the path will have to be corrected. At a second cosmic speed of 11 km / s (40,000 km / h), the flight will theoretically take about 10 hours, but in reality it will take longer. This is because the ship at the start gradually increases its speed in the atmosphere, bringing it to a value of 11 km / s in order to escape from the Earth's gravitational field. Then the ship will have to slow down when approaching the moon. By the way, this speed is the maximum that modern spacecraft have managed to achieve.

The notorious 1969 flight of the Americans to the moon took 76 hours, according to official figures. NASA's New Horizons spacecraft managed to reach the Moon the fastest - in 8 hours 35 minutes. True, he did not land on the planetoid, but flew past - he had another mission.

Light from Earth will reach our satellite very quickly - in 1.255 seconds. But flying at light speeds is still out of the realm of fantasy.

You can try to imagine the path to the moon in the usual values. On foot at a speed of 5 km / h, the road to the Moon will take about nine years. If you go by car at a speed of 100 km / h, then it will take 160 days to get to the earth's satellite. If planes flew to the moon, the flight to it would last about 20 days.

How astronomers in ancient Greece calculated the distance to the moon

The moon became the first celestial body to which it was possible to calculate the distance from the Earth. It is believed that astronomers were the first to do this in ancient Greece.

They have tried to measure the distance to the moon since time immemorial - the first to try to do this was Aristarchus of Samos. He estimated the angle between the Moon and the Sun at 87 degrees, so it turned out that the Moon is 20 times closer than the Sun (the cosine of an angle equal to 87 degrees is 1/20). The angle measurement error resulted in a 20-fold error, today it is known that this ratio is actually 1 in 400 (the angle is approximately 89.8 degrees). The large error was caused by the difficulty of estimating the exact angular distance between the Sun and the Moon using primitive astronomical instruments of the Ancient World. Regular solar eclipses by this time had already allowed ancient Greek astronomers to conclude that the angular diameters of the Moon and the Sun were approximately the same. In this regard, Aristarchus concluded that the Moon is 20 times smaller than the Sun (in fact, about 400 times).

Aristarchus used a different method to calculate the size of the Sun and Moon relative to the Earth. We are talking about observing lunar eclipses. By this time, ancient astronomers had already guessed the reasons for these phenomena: the Moon is eclipsed by the shadow of the Earth.

The diagram above clearly shows that the difference in the distances from the Earth to the Sun and to the Moon is proportional to the difference between the radii of the Earth and the Sun and the radii of the Earth and its shadow at the distance of the Moon. At the time of Aristarchus, it was already possible to estimate that the radius of the moon is approximately 15 arc minutes, and the radius of the earth's shadow is 40 arc minutes. That is, the size of the moon turned out to be about 3 times smaller than the size of the earth. From here, knowing the angular radius of the Moon, it was easy to estimate that the Moon is about 40 Earth diameters from the Earth. The ancient Greeks could only roughly estimate the size of the Earth. So Eratosthenes of Cyrene (276 - 195 BC), based on the differences in the maximum height of the Sun above the horizon in Aswan and Alexandria during the summer solstice, determined that the Earth's radius is close to 6287 km (the current value is 6371 km). If we substitute this value into Aristarchus's estimate of the distance to the Moon, then it will correspond to about 502 thousand km (the modern value of the average distance from the Earth to the Moon is 384 thousand km).

A little later, a mathematician and astronomer of the 2nd century BC. e. Hipparchus of Nicaea calculated that the distance to the earthly satellite is 60 times greater than the radius of our planet. His calculations were based on observations of the movement of the moon and its periodic eclipses.

Since at the time of the eclipse the Sun and the Moon will have the same angular dimensions, then according to the rules of similarity of triangles, the ratio of the distances to the Sun and the Moon can be found. This difference is 400 times. Applying these rules again, only in relation to the diameters of the Moon and the Earth, Hipparchus calculated that the diameter of the Earth is 2.5 times the diameter of the Moon. That is, R l \u003d R s / 2.5.

At an angle of 1 ', one can observe an object whose dimensions are 3483 times smaller than the distance to it - this information was known to everyone in the time of Hipparchus. That is, with an observed radius of the Moon of 15 ′, it will be 15 times closer to the observer. Those. the ratio of the distance to the moon to its radius will be 3483/15 \u003d 232 or S l \u003d 232R l.

Accordingly, the distance to the Moon is 232 * R s / 2.5 \u003d 60 Earth radii. This turns out to be 6 371 * 60 \u003d 382 260 km. The most interesting thing is that the measurements made with modern instruments confirmed the correctness of the ancient scientist.

Now the measurement of the distance to the moon is carried out using laser devices, which can be measured with an accuracy of several centimeters. In this case, measurements take place in a very short time - no more than 2 seconds, during which the Moon moves away in orbit about 50 meters from the point of sending the laser pulse.

The evolution of methods for measuring the distance to the moon

Only with the invention of the telescope, astronomers were able to obtain more or less accurate values \u200b\u200bof the parameters of the Moon's orbit and the correspondence of its size to the size of the Earth.

A more accurate method for measuring the distance to the moon appeared in connection with the development of radar. The first radar of the Moon was carried out in 1946 in the USA and Great Britain. Radar made it possible to measure the distance to the moon with an accuracy of several kilometers.

An even more accurate method of measuring the distance to the moon has become laser ranging. For its implementation in the 1960s, several corner reflectors were installed on the Moon. It is interesting to note that the first experiments on laser ranging were carried out even before the installation of corner reflectors on the lunar surface. In 1962-1963, several experiments were carried out at the Crimean Observatory of the USSR on laser ranging of individual lunar craters using telescopes with a diameter of 0.3 to 2.6 meters. These experiments were able to determine the distance to the lunar surface with an accuracy of several hundred meters. In 1969-1972, the Apollo astronauts delivered three corner reflectors to the surface of our satellite. Among them, the most perfect was the reflector of the Apollo 15 mission, since it consisted of 300 prisms, while the other two (the Apollo 11 and Apollo 14 missions) had only one hundred prisms each.

In addition, in 1970 and 1973, the USSR delivered to the lunar surface two more French corner reflectors on board the self-propelled vehicles Lunokhod-1 and Lunokhod-2, each of which consisted of 14 prisms. The first of these reflectors has an extraordinary history. During the first 6 months of operation of the Lunokhod with a reflector, it was possible to carry out about 20 sessions of laser ranging. However, then, due to the unfortunate position of the lunar rover, it was not possible to use the reflector until 2010. Only the images of the new LRO spacecraft helped to clarify the position of the lunar rover with the reflector, and thus resume the sessions of work with it.

In the USSR, the largest number of laser ranging sessions was carried out with the 2.6-meter telescope of the Crimean Observatory. Between 1976 and 1983, 1400 measurements were made with this telescope with an error of 25 centimeters, then observations were stopped due to the curtailment of the Soviet lunar program.

In total, from 1970 to 2010, approximately 17 thousand high-precision laser ranging sessions were conducted in the world. Most of them were associated with the Apolonna 15 corner reflector (as mentioned above, it is the most perfect - with a record number of prisms):

Of the 40 observatories that are capable of laser ranging of the moon, only a few can perform high-precision measurements:

Most of the ultra-precise measurements were made with a 2-meter telescope at the McDonald Observatory in Texas:

At the same time, the most accurate measurements are performed by the APOLLO instrument, which was installed on the 3.5-meter telescope of the Apache Point Observatory in 2006. The accuracy of its measurements reaches one millimeter:

Evolution of the Moon and Earth system

The main goal of increasingly accurate measurements of the distance to the Moon is to try to better understand the evolution of the Moon's orbit in the distant past and in the distant future. To date, astronomers have come to the conclusion that in the past the Moon was several times closer to the Earth, and also had a much shorter rotation period (that is, it was not tidally captured). This fact confirms the impact version of the formation of the Moon from the ejected matter of the Earth, which prevails in our time. In addition, the tidal effect of the moon leads to the fact that the speed of rotation of the earth around its axis gradually slows down. The rate of this process is an increase in the Earth's day every year by 23 microseconds. In one year, the Moon moves away from the Earth by an average of 38 millimeters. It is estimated that if the Earth-Moon system survives the transformation of the Sun into a red giant, then in 50 billion years the Earth's day will be equal to the lunar month. As a result, the Moon and Earth will always be turned to each other by only one side, as is now observed in the Pluto-Charon system. By this time, the Moon will move away to about 600 thousand kilometers, and the lunar month will increase to 47 days. In addition, it is assumed that the evaporation of the Earth's oceans in 2.3 billion years will lead to an acceleration of the Moon's removal process (Earth's tides significantly slow down the process).

In addition, calculations show that in the future the Moon will again begin to approach the Earth due to the tidal interaction with each other. When approaching the Earth by 12 thousand km, the Moon will be torn apart by tidal forces, the fragments of the Moon form a ring like the well-known rings around the giant planets of the Solar System. Other well-known satellites of the Solar System will repeat this fate much earlier. So Phobos is assigned 20-40 million years, and Triton is about 2 billion years old.

Each year, the distance to the earth's satellite increases by an average of 4 cm. The reasons are the movement of the planetoid in a spiral orbit and the gradually decreasing power of the gravitational interaction of the Earth and the Moon.

Theoretically, all the planets of the solar system can be placed between the Earth and the Moon. If you add up the diameters of all the planets, including Pluto, you get a magnitude of 382,100 km.

The natural satellite of the Earth is the Moon - a non-luminous body that reflects sunlight.

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

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

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

General characteristics of the moon

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

The Moon's mass is 1/81 of the Earth's mass. The position of the Moon in its orbit corresponds to one or another phase (Fig. 1).

Figure: 1. Phases of the Moon

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

The Moon is always facing the Earth with one side.

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

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

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

The intersection of the orbits of the Earth and the Moon are called nodes of the lunar orbit.

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

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

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

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

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

Investigations of spacecraft "Luna-16", "Luna-20", "Luna-24" have shown that the surface clastic rocks of the Moon are similar to terrestrial igneous rocks - basalts.

The meaning of the moon in the life of the earth

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

Due to the gravitational influence of the Moon and the Sun on the Earth, ebb and flow (fig. 2).

Figure: 2. Scheme of the occurrence of ebb and flow on Earth

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

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

On Earth, 2 tides are observed at the point closest and remote from the Moon and 2 ebb tides at points located at an angular distance of 90 ° from the Moon - Earth line. Allocate sigisial tides, which occur on new and full moon and quadrature - in the first and last quarter.

In the open ocean, tidal events are small. Fluctuations in the water level reach 0.5-1 m. In the inland seas (Black, Baltic, etc.), they are almost not felt. However, depending on the latitude and outlines of the coastline of the continents (especially in narrow bays), the water during high tides can rise up to 18 m (Bay of Fundy in the Atlantic Ocean off the coast of North America), 13 m on the western coast of the Sea of \u200b\u200bOkhotsk. In this case, tidal currents are formed.

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

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

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

A solar eclipse occurs when the Moon gets between the observer and the Sun and obscures it. Since the Moon before the eclipse is facing us with its unlit side, there is always a new moon before the eclipse, that is, the Moon is not visible. One gets the impression that the Sun is covered with a black disk; the observer from the Earth sees this phenomenon as a solar eclipse (Fig. 3).

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

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

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

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 Earth satellite, orbiting the Earth for more than 3.5 billion years. That is, the Moon accompanies humanity from the moment of its appearance.

Due to its brightness and accessibility in direct observation, 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 close look at some interesting facts about the moon.

There is no "dark side"

• There are many stories about the other side of the moon. In reality, both sides receive the same amount of sunlight, but only one of them is available for terrestrial viewing. The fact is that the time of the axial lunar rotation coincides with the orbital one, which means that it is always turned to us with one side. But we are exploring the "dark side" with spacecraft.

The moon affects the earth's tides

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

The moon is trying to escape

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

The weight on the moon is much lighter

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

12 astronauts visited the moon

• In 1969, Neil Armstrong was the first to step onto the satellite during the Apollo 11 mission. The last 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 seen in the photo, is devoid of protection from cosmic radiation, meteorite strikes and solar wind. Serious temperature fluctuations are also noticeable. You will not hear sounds, and the sky always looks black.

There are earthquakes

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

The first device arrived in 1959

• The first to visit the moon was the Soviet apparatus Luna-1. It flew past the satellite at a distance of 5995 km, and then went into orbit around the Sun.

Ranked 5th in the system

• In diameter, the earth's satellite extends 3475 km. The Earth is 80 times larger than the Moon, but their age is about the same. The main theory is that at the beginning of 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 people will always be there. Work may begin as early as 2019.

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

• It was a covert Cold War project - Project A119. This would show a significant preponderance of one of the countries.

The 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, therefore it is inferior to our planet in everything. However, if we compare it with the celestial bodies of the solar system, it can be seen that it is rather large in size (in the second position after Charon). The density index is 3.3464 g / cm 3 (in second place among moons after Io), and gravity is 1.622 m / s 2 (17% of the earth).

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 complete a walk around the planet. In addition, the satellite is in the gravitational block, that is, it always looks at us with one side.

Physical characteristics of the moon

Polar compression	0,00125
Equatorial	1738.14 km 0.273 Earth
Polar radius	1735.97 km 0.273 Earth
Average radius	1737.10 km 0.273 Earth
Large circumference	10 917 km
Surface area	3.793 · 10 7 km² 0.074 Earth
Volume	2.1958 · 10 10 km³ 0.020 terrestrial
Weight	7.3477 10 22 kg 0.0123 terrestrial
Average density	3.3464 g / cm³
Speeding up free falls at the equator	1.62 m / s²
The first space speed	1.68 km / s
Second space speed	2.38 km / s
Rotation period	synchronized
Axis tilt	1.5424 °
Albedo	0,12
Apparent magnitude	−2,5/−12,9 −12.74 (full moon)

The composition and surface of the moon

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

Also in the mantle you can find igneous rocks, where iron is more than ours. The crust stretches 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 shaded crater formations and subsurface reservoirs. It is believed that it appeared due to the contact of the satellite with the solar wind.

Lunar geology is at odds with the terrestrial. The satellite is devoid of a dense atmospheric layer, so there is no weather and wind erosion on it. Small size and low gravity result in rapid cooling and lack of tectonic activity. A huge number of craters and volcanoes can be noted. Ridges, wrinkles, highlands and depressions are everywhere.

The contrast between bright and dark areas is most noticeable. The former are called lunar heights, 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 the lowlands. Channels can be marked. They are arched and linear. These are lava tubes, cooled and destroyed since the volcanic hibernation.

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

A notable feature of our satellite is impact craters that form when large space rocks fall. Kinetic shock energy forms a shockwave leading to depression, causing a lot of material to escape.

Craters extend from small pits up to 2500 km and a depth of 13 km (Aitken). The largest appeared in early history, after which they began to decrease. Approximately 300,000 depressions with a width of 1 km can be found.

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

The chemical composition of the regolith differs depending on the position. If the mountains are rich in aluminum and silicon dioxide, then the seas are capable of boasting iron and magnesium. Geology was investigated not only by telescopic observations, but also by the analysis of samples.

Atmosphere of the moon

The Moon has a weak layer of the atmosphere (exosphere), which is why the temperature indicator fluctuates greatly: from -153 ° C to 107 ° C. 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.

Moon formation

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

The main theory is shock. It is believed that a large object (Theia) flew into the proto-Earth 4.5 billion years ago. The torn material began to spin along our orbital path and formed the Moon. This is confirmed by computer models. In addition, the tested samples showed isotopic compositions almost identical to ours.

Earth connection

The moon rotates around the Earth in 27.3 days (stellar period), but both objects move around the Sun at the same time, so the satellite spends 29.5 days for 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 when sea levels rise. The earth's rotation is 27 times faster than the moon. Ocean tides are also amplified by the frictional adhesion of water to the Earth's rotation through ocean floors, water inertia, and basin oscillation.

The angular momentum accelerates the lunar orbit and lifts the satellite higher with 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 blocking, repeating the situation of Pluto and Charon. But it will take billions of years. So rather, the Sun will become a red giant and swallow us.

Tides are also noted on the lunar surface with an amplitude of 10 cm for 27 days. Cumulative stress leads to moonbeams. And they last an hour longer because there is no water to drown out 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 appears if the full moon is shown behind the earth's shadow, and the solar - the moon is located between the star and the planet. With a total eclipse, you can see the solar corona.

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

Moon observation history

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

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

The connection between the tides and the moon was announced 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 the size was obtained by Aristarchus. His data was improved by Ptolemy.

The Chinese began to predict lunar eclipses in the 4th century BC. They already knew then that the satellite reflects sunlight and is made in a spherical shape. Alhazen said that the sun's rays are not mirrored, but radiated from each lunar site in all directions.

Until the advent of the telescope, everyone believed that they saw a spherical object, and also perfectly smooth. In 1609, the first sketch from Galileo Galilei appears, depicting craters and mountains. This and observations of other objects helped advance Copernicus's heliocentric concept.

The development of telescopes has led to the detailing of surface features. All craters, mountains, valleys and seas are named after 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 age of lunar exploration has allowed a closer look at the neighbor. The Cold War between the USSR and the United States became the reason that all technologies developed rapidly, and the Moon became the main target of research. It all started with launches of vehicles, and ended with human missions.

In 1958, the Soviet Luna program was launched, where the first three probes crashed on the surface. But a year later, the country successfully delivers 15 vehicles and obtains the first information (information on gravity and surface images). Samples were delivered on 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 only to surface survey.

At NASA, the launch of probes started in the 60s. In the 1961-1965's. the Ranger program was in operation, which created a map of the lunar landscape. Further in the 1966-1968's. rovers landed.

In 1969, a real miracle happened when Apollo 11 astronaut Neil Armstrong took the first step on a satellite and became the first person on the moon. This was the culmination of the Apollo mission, which was originally aimed at human flight.

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

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

In 2000, many countries were eager to explore the satellite. ESA sent ship SMART-1, which first analyzed the chemical composition in detail in 2004. China launched the Chane program. The first probe arrived in 2007 and spent 16 months in orbit. The second device also managed to capture the arrival of the asteroid 4179 Tutatis (December 2012). Chanye-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. From 2008-2009, the first mission from the Indian ISRO Chandrayan rotated in orbit. They were able to create high-resolution chemical, mineralogical and photogeological maps.

NASA used the LRO and the LCROSS satellite in 2009. The internal structure was reviewed 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 closed for a long time in special domes. America is not lagging behind, which also intends to populate the moon.

Use the resources of our site to view beautiful and high-quality high-resolution photos of the Moon. Useful links will help you find out the maximum known amount of information about a satellite. To understand what the moon is today, just go to the appropriate sections. If you cannot buy a telescope or binoculars, then look at the moon in 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.

Satellites of the Earth: from artificial to natural

Astronomer Vladimir Surdin on expeditions to the moon, the Apollo 11 landing site, and cosmonaut equipment:

Click on the image to enlarge it

The Moon's mass averages about 7.3477 x 10 22 kg.

The moon is the only satellite of the Earth and the celestial body closest to it. The source of the moon's glow is the Sun, therefore we always observe only the lunar part facing the great luminary. The second half of the Moon at this time is immersed in cosmic darkness, waiting for its turn to come out "into the light". The distance between the Moon and the Earth is approximately 384,467 km. So, today we will find out how much the moon weighs in comparison with other "inhabitants" of the solar system, and also learn interesting facts about this mysterious earthly satellite.

Why is the moon called that?

The ancient Romans called the moon the goddess of night light, whose name was eventually named the night star itself. According to other sources, the word "moon" has Indo-European roots and means "bright" - and for good reason, because in terms of brightness, the earth's satellite is in second place after the Sun. In ancient Greek, a star shining with a cold yellowish light in the night sky was named after the goddess Selene.

What is the weight of the moon?

The moon weighs about 7.3477 x 1022 kg.

Indeed, in the physical plane, there is no such thing as "the weight of the planet". After all, the weight is the force of the body's action on a horizontal surface. Alternatively, if the body is suspended on a vertical thread, then its weight is the tensile force of the body of this thread. It is clear that the Moon is not located on the surface and is not in a "suspended" state. So, from a physical point of view, the Moon has no weight. Therefore, it will be more appropriate to talk about the mass of this celestial body.

The weight of the moon and its motion - what is the relationship?

For a long time, people have tried to unravel the "mystery" of the motion of the Earth's satellite. The theory of the motion of the moon, first developed by the American astronomer E. Brown in 1895, has become the basis of modern calculations. However, to determine the exact motion of the moon, it was required to know its mass, as well as various coefficients of trigonometric functions.

However, thanks to the achievements of modern science, it became possible to carry out more accurate calculations. Using the laser ranging method, you can determine the size of a celestial body with an error of only a couple of centimeters. So, scientists have revealed and proved that the mass of the Moon is 81 times less than the mass of our planet, and the radius of the Earth is 37 times more than a similar lunar parameter.

Of course, such discoveries became possible only with the advent of the era of space satellites. But the scientists of the epoch of the great "discoverer" of the law of universal gravitation, Newton, determined the mass of the moon by examining the tides caused by periodic changes in the position of a celestial body relative to the Earth.

Moon - characteristics and numbers

• surface - 38 million km 2, which is approximately 7.4% of the Earth's surface
• volume - 22 billion m3 (2% of the value of a similar earth indicator)
• average density - 3.34 g / cm 3 (near the Earth - 5.52 g / cm 3)
• gravity - equal to 1/6 of the earth

The moon is a rather "heavy" celestial satellite, not typical for terrestrial planets. If we compare the mass of all planetary satellites, then the Moon will be in fifth place. Even Pluto, which until 2006 was considered a full-fledged planet, is more than five times less than the Moon in mass. As you know, Pluto consists of rocks and ice, so that its density is low - about 1.7 g / cm 3. But Ganymede, Titan, Callisto and Io, which are satellites of the giant planets of the solar system, exceed the mass of the moon.

It is known that the force of gravity or gravity of any body in the Universe consists in the presence of an attractive force between different bodies. In turn, the magnitude of the force of attraction depends on the mass of the bodies and the distance between them. So, the Earth attracts a person to its surface - and not vice versa, since the planet is much larger in size. In this case, the force of gravity is equal to the weight of a person. Let's try to double the distance between the center of the Earth and a person (for example, we will climb a mountain 6,500 km above the earth's surface). Now a person weighs four times less!

But the Moon is significantly inferior in mass to the Earth, therefore, the lunar gravity is also less than the earth's gravity. So the astronauts, who first landed on the lunar surface, could make unimaginable jumps - even with a weighty spacesuit and other "space" equipment. Indeed, on the moon, a person's weight decreases as much as six times! The most suitable place for setting the "interplanetary" Olympic records in high jump.

So, now we know how much the Moon weighs, its main characteristics, as well as other interesting facts about the mass of this mysterious earthly satellite.

Of all the parameters of celestial bodies, mass is the most difficult to calculate. Therefore, unlike the diameter, the mass of the Moon was calculated relatively recently.

Among the satellites, it is in sixth place in terms of mass. Its mass is 7.34x1022 kg, which is 80 times less than the earth's. You can calculate the average density of the Moon - 3.35 g / cm3, which is 3-4 times more than that of other satellites (except for the satellite), as well as the acceleration of gravity - 1.62 m / s2, and the force of gravity, which is 1/6 of the earth, that is, an object moved from to its satellite, would weigh six times less. Due to weak gravity, the moon has no atmosphere.

Gravitational influence

The moon is an abnormally large and massive satellite, so it has a tangible gravitational effect on the planet. The main manifestation of this effect is the ebb and flow.
Tidal forces arise along the Moon-Earth axis. The closer the area of \u200b\u200bthe Earth is to the Moon, the more it is attracted to it. Different degrees of attraction at different points cause deformation of the globe, resulting in the ebb and flow of the sea.
As a result, the gravity of the Moon affects the Earth's crust, atmosphere and hydrosphere of the Earth, and even its geomagnetic field.
The Earth and the Moon form a single system of mass, the center of which is located at a distance of 4750 km from the center of the Earth.

How measured

Newton was the first to try to calculate the mass of the moon, using measurements taken during sea tides, but got a result that was twice the true value. They were able to correctly calculate the mass of the satellite after Cavendish experimentally determined the exact value of the gravitational constant.