The main indicators of the Earth's satellite: the mass of the Moon, diameter, features of movement and research. Our natural satellite is the moon

The sizes of objects in the Universe in comparison (photo)

1. This is the Earth! We live here. At first glance, it looks very large. But, in fact, compared to some objects in the Universe, our planet is negligible. The following photos will help you at least roughly imagine something that simply does not fit in your head.

2. Location of planet Earth in Solar system.

3. The scaled distance between the Earth and the Moon. Doesn't look too far, does it?

4. Within this distance, you can place all the planets of our solar system, beautifully and neatly.

5. This small green spot is the continent of North America, on the planet Jupiter. One can imagine how much larger Jupiter is than Earth.

6. And this photo gives an idea of ​​the size of the planet Earth (that is, six of our planets) in comparison with Saturn.

7. This is how the rings of Saturn would look if they were around the Earth. Beauty!

8. Hundreds of comets fly between the planets of the solar system. This is how comet Churyumov-Gerasimenko looks like, on which the Philae probe landed in the fall of 2014, in comparison with Los Angeles.

9. But all objects in the solar system are insignificant small in comparison with our sun.

10. This is how our planet looks from the surface of the Moon.

11. This is how our planet looks from the surface of Mars.

12. And this is us from Saturn.

13. If you fly to the border of the solar system, you will see our planet like this.

14. Let's go back a little. This is the size of the Earth compared to the size of our Sun. Impressive, isn't it?

15. And this is our Sun from the surface of Mars.

16. But our Sun is only one of the stars in the Universe. Their number is more than grains of sand on any beach on Earth.

17. This means that there are stars much larger than our Sun. Just look how tiny the Sun is compared to the largest star known to date, VY, in the constellation Canis Major.

18. But no star can match the size of our Milky Way Galaxy. If we reduce our Sun to the size of a white blood cell and reduce the entire Galaxy by the same factor, then the Milky Way will be the size of Russia.

19. Our Milky Way Galaxy is huge. We live somewhere here.

20. Unfortunately, all objects that we can see with the naked eye in the sky at night are placed in this yellow circle.

21. But the Milky Way is far from the largest galaxy in the Universe. This is the Milky Way compared to Galaxy IC 1011, which is 350 million light-years from Earth.

22. But that's not all. This Hubble telescope image captures thousands and thousands of galaxies, each containing millions of stars with their own planets.

23. For example, one of the galaxies in the photo, UDF 423. This galaxy is located ten billion light years from Earth. When you look at this photo, you are looking back billions of years.

24. This dark piece of the night sky looks completely empty. But when zoomed in, it turns out to contain thousands of galaxies with billions of stars.

25. And this is the size of the black hole compared to the size of the Earth's orbit and the orbit of the planet Neptune.

One such black abyss can easily suck in the entire solar system.

In 1609, after the invention of the telescope, mankind was able to examine its space satellite in detail for the first time. 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 full-fledged 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 is known in the solar system, 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 a common center of mass. 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 there were volcanoes 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 on the 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 most powerful, 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 current 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 to Earth many times, there is still room for discovery. For example, scientists are hunting for lunar anomalies - mysterious flares and auroras on the surface of the Moon, 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 the 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 yet 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 the fluctuations of the orbits, 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 full turnover around the Earth and the change of lunar phases requires 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 on 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, resembling 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. 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 forest - 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 - a whopping 16 lux. Of course, all light is not own, but reflected from the sun.

• 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

It took people a long time to understand how big the moon is and what it is made of. 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 the Moon is covered, the 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. The Soviet cosmonauts, who watched the broadcast of the astronauts' landing in real time, also confirmed the accuracy of what was happening. And who can deceive an expert in his field?

And complete geological and topographic maps of our satellite are being compiled to this day. In 2009, the LRO space station (Lunar Reconnaissance Orbiter) not only delivered the most detailed images of the Moon in history, but also proved the presence of a large amount of frozen water on it. 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 impacts of meteorites, the density of which is lower than 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: a fall in a vacuum was quite dangerous. Below is a video of the astronaut jumping from the live broadcast.

• Lunar seas cover about 17% of the entire Moon - mainly it visible side, which is almost a third covered by them. They are traces of the impacts of especially heavy meteorites, which literally ripped off its crust from the satellite. In these places, the surface is separated from the lunar mantle only by a thin, half-kilometer layer of solidified lava - basalt. Since the concentration of solids increases closer to the center of any large cosmic body, 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 hugely 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 affected 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 duration of the 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 collision was reflected in the further development of the 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 high temperature and absence magnetic field... However, some processes are still taking place inside - because of the movements in the lithosphere of the Moon, moonquakes sometimes occur. 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 orbiting 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 rather 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 moved away. However, it will not be able to completely crash into it. 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 a nuclear one, and the rest will form a ring around the planet. However, it will not be so bright - the rings of the gas giants are composed 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 "exploration of 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 - finding valuable resources, mining them, and then bringing them back home. However, this does not apply to space - in the next couple of hundred years, delivering a kilogram of gold even from the nearest asteroid will cost more than 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 in astronautics today is spacecraft weight restrictions. 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 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, assembled from parts delivered from Earth. And the assembly on the moon will be much easier than in low-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 people of the whole world to achieve such a valuable unity. For in the unity of humanity lies the true strength of the Earth.

Apart from the scattering of stars, the moon is undoubtedly the decoration of the night sky. Due to the combination of its size and distance from Earth, it is the second brightest celestial object and can completely obscure the solar disk during an eclipse. It is not surprising that the night star has been attracting the attention of mankind for more than one millennium.

If the Earth did not have the Moon, many things would have turned out differently:

• the day would be much shorter;
• the change of seasons and the climate would be characterized by instability;
• less pronounced ebb and flow would occur;
• the appearance on the planet of life in its present form would be questionable.

The average value of the moon's diameter is not too large by cosmic standards - 3474.1 km. This is approximately half the distance from Moscow to Vladivostok.

However, the Moon is ranked fifth place in size among the natural satellites of the planets of the solar system:

1. Ganymede.
2. Titanium.
3. Callisto.
4. Moon.

But even when comparing the sizes of satellites in relation to their planets, the moon has no equal. With a diameter of a quarter of the earth, it ranks first. In addition, it is larger than Pluto.

What is the distance from the Earth to the Moon

The quantity is not constant. On average, the distance between the centers of the planet and its natural satellite is 384,400 kilometers. In this space, about 30 more Earths would fit, and light needs 1.28 seconds to overcome this distance.

What if the nearest celestial body could be reached by car at a speed of 95 km / h? Considering that the entire distance is about 10 circles of the Earth, the journey would take the same amount of time as 10 detours of the planet along the equator. That is, a little less than six months. So far, the fastest way to the Moon was covered by the New Horizons interplanetary station, which on its way to Pluto crossed the satellite's orbit eight and a half hours after launch.

The moon's orbit is not a perfect circle, and an oval (ellipse), inside which is the Earth. At different points, it is located closer to or further from the planet. Because of this, when rotating around a common center of mass with the Earth, the satellite either approaches or moves away. So, the least kilometers are separated by celestial bodies when the night star is in the place of the orbit called perigee. At the point designated as the apogee, the satellite is farthest from the planet. The minimum distance is 356 400 km, and the maximum is 406 700 km. So the distance fluctuates from 28 to 32 earth diameters.

The first close to correct estimates of the distance to the "neighbor" of the Earth were obtained in the II century. n. e. Ptolemy. Nowadays, thanks to modern reflective devices installed on the satellite, it was possible to measure the distance most accurately (with an error of several cm). To do this, a laser beam is directed at the moon. Then they note during what period it will return to the Earth, being reflected. Knowing the speed of light and the time it took for it to reach the sensors, it’s easy to calculate the distance.

How to visually estimate the size of the moon and its distance from the earth

Earth's diameter is about 4 times the Lunar diameter, and the volume - 64 times. The distance to the night star is approximately 30 times the planet's diameter. To visually assess the distance from the Earth to its satellite and compare their sizes, you need two balls: a basketball and a tennis one. Diameter ratio:

• Earth (12,742 km) and the Moon (3474.1 km) - 3.7: 1;
• standard basketball (24 cm) and tennis (6.7 cm) - 3.6: 1.

The values ​​are pretty close. Thus, if the Earth were the size of a basketball, then its satellite would be a tennis one.

You can ask people to imagine that the Earth is a basketball, and the Moon is a tennis ball, and to show how far the satellite is from the planet on this scale. Most are likely to assume a distance of 30 cm to a few steps.

In fact, to show the correct distance, you have to move a little more than seven meters. So, between the planet and its satellite, on average, 384 400 km, which is about 30 Earths or, respectively, 30 basketballs. Diameter multiplication sports equipment at 30 gives the result of 7.2 m. This is approximately 9 male or 11 female steps.

The apparent size of the moon from Earth

360 angular degrees- the entire circumference of the celestial sphere. At the same time, the night star occupies about half of one degree on it (on average 31 minutes) - this is the angular (visible) diameter. For comparison: the width of the index finger nail at arm's length is about one degree, that is, two moons.

By a unique coincidence, the apparent sizes of the Sun and the Moon for the inhabitants of the Earth are almost the same. This is possible due to the fact that the diameter of the nearest star 400 times the diameter of the satellite, but the daylight is also located the same number of times further. Due to this coincidence, among all the planets orbiting the Sun, only on Earth can its total eclipse be observed.

Is the size of the moon changing

Of course, the true diameter of the satellite remains the same, but the apparent size can vary. So, The moon appears to be noticeably larger during sunrise and sunset.... When a night star is low above the horizon, the distance to the observer does not decrease, but, on the contrary, slightly increases (by the radius of the Earth). The visual effect, it would seem, should be the opposite. There is no single answer to explain the reason for the illusion. We can only say with certainty that this beautiful phenomenon owes its existence only to the peculiarities of the work of the human brain, and not, for example, to the influence of the Earth's atmosphere.

The distance between the Moon and the Earth periodically changes from maximum (at apogee) to minimum (at perigee). Along with the distance, the apparent diameter of the satellite also varies: from 29.43 to 33.5 arc minutes. Thanks to this, not only total eclipses are possible, but also annular (when the apparent size of the moon at apogee is less than the solar disk). About once every 414 days, the full moon coincides with the passage of the perigee. At this time, you can observe the largest night star. The phenomenon has received the rather loud name of a supermoon, but the apparent diameter at this moment is only 14% larger than usual. The difference is very insignificant, and a simple observer will not notice the difference.

Thanks to precise measurements distance, scientists were able to detect a relatively slow, but constant increase in the distance between the Earth and its satellite. The speed at which the moon is receding - 3.8 cm per year - is too slow to notice a significant decrease in the apparent size of the star. Human nails grow at about the same rate. Nevertheless, after 600 million years, the Moon will be so far away and, accordingly, will decrease for terrestrial observers that total solar eclipses will remain in the past.

It is worth noting, what a satellite of the earth, formed according to modern theory from the collision of a planet with a large object 4.5 billion years ago, was originally 10-20 times closer. However, admire the sky, decorated with a luminary 10-20 times larger diameter than now, then there was no one.

The moon is a natural satellite of planet Earth, which is considered the only celestial body closest to it. Scientists believe that the distance between the Earth and its satellite is about 384 thousand km.

What you need to know about the Earth's satellite?

In order to have a general idea of ​​this celestial body, it is necessary to consider a number of its features: these are the volume of the satellite, its diameter, surface area and the mass of the Moon.

The moon is moving in an elliptical orbit, and its speed is approximately 1.02 km / sec. If you observe the Moon from the side of the North Pole of the Earth, then it turns out that it moves in the same direction as most other visible celestial bodies, that is, counterclockwise. The force of gravity on the moon is 1.622 m / s².

Since ancient times, many scientists and astronomers have been interested in such indicators as the distance of the satellite from the Earth, its influence on the climate, the mass of the Moon and other characteristics. The process of studying celestial bodies, by the way, began a long time ago.

The study of the moon in antiquity

The moon is a very bright celestial body, which simply could not fail to attract the attention of scientists in ancient times. Astronomers, thousands of years ago, were interested in what the mass of the moon is equal to, how there were changes in its phases.

It's no secret that many nations even worshiped this heavenly body. Astronomers of Ancient Babylon were able to calculate the change in lunar phases with great accuracy. Scientists of the twentieth century, equipped with the most modern instruments, corrected this number by just 0.4 seconds. But then it was not yet known what the mass of the Moon and the Earth was.

More recent research

The moon is the most studied body in the sky. Scientists different countries about a hundred satellites were launched to study it. The first in the world research apparatus was launched by the Soviet satellite "Luna-1". This event took place in 1959. Then the research complex was able to descend to the lunar surface, take soil samples, transfer photographs to Earth, and roughly calculate what is the mass of the moon. In addition to this satellite, the Soviet Union also delivered two lunar rovers to the lunar surface. One of them functioned for almost 10 months, having covered a distance of 10 km, and the second - 4 months, having covered 37 km.

The main indicators of the moon

The diameter of the moon is 3474 km. Moreover, the diameter of the Earth is 12,742 km. In other words, the circumference of the moon is only 3/11 of the diameter of our planet.

The surface area of ​​the Earth's satellite is 37.9 million square meters. km. In comparison with the indicators of the planet, this is also much less, because the surface area of ​​the Earth is 510 million square meters. km. Even if we compare the lunar surface only with the terrestrial continents, it turns out that the area of ​​the moon is 4 times less. The volume that the Earth occupies is 50 times that of the lunar.

A little more about the mass of the moon

The mass of the moon was most accurately determined using artificial satellites. It is 7.35 * 10 22 kilograms. For comparison, the mass of the Earth is 5.9742 × 10 24 kilograms.

The mass of the Moon and Earth is constantly changing slightly. For example, the Earth is subject to a small meteorite bombardment. About 5-6 tons of meteorites fall on the earth's surface per day. But at the same time, the Earth loses more mass due to the evaporation of helium and hydrogen from the atmosphere into outer space. These losses already amount to about 200-300 tons per day. The Moon, of course, has no such losses. The average density of matter on the moon is about 3.34 g per 1 cm 3.

Such a value as the acceleration of gravity on a satellite of the Earth is 6 times greater than on the Earth itself. The density of those rocks that make up the moon is about 60 times less than the density of the earth. Therefore, the mass of the Moon is 81 times less than the mass of the Earth.

Since the Moon has a very small attraction, there is practically no atmosphere around it - there is no gas shell and water in a free state. The period of the Moon's revolution around the earth is called sidereal, or stellar. It is 27.32166 days. But this number is subject to minor changes over time.

Lunar phases

The moon does not glow on its own. A person can see only those parts of it, which are exposed to the rays of the Sun, reflected from the surface of the Earth. In this way, the lunar phases can be explained. The moon, moving in its orbit, passes between the sun and the earth. At this time, it is facing the Earth with its unlit side. This period is called the new moon. 1-3 days after that, in the western part of the sky, you can see a small narrow crescent - this is the visible part of the moon. About a week later, the second quarter begins, when exactly half of the Earth's satellite is illuminated.

The moon is the only satellite of the earth. The first person to investigate it was Galileo. The same scientist also made the first discoveries about the Earth's satellite: its approximate dimensions, craters and valleys on the surface. Now anyone can make Galileo's discoveries by simply using binoculars.

Moon and planets of the solar system: comparison

The volume of the Moon is 21.99 * 10 9 km 3. Its mass is 7.35 * 10 22 kg. Knowing these values, one can compare the sizes of the Moon and the Earth. The volume of the Earth is 10.8321 * 10 11 km 3. Its mass is 5.9726 * 10 24 kg. Thus, the volume of the Moon is 0.020 and its mass is 0.0123. You can also compare the size of the Moon and Mars. The volume of the red planet is 6.083 * 10 10 km, its mass is 3.33022 * 10 23 kg. Consequently, Mars is approximately twice as large.

The moon differs in many respects from other satellites of the planets of the solar system, not only in size, but also in other parameters. It is believed that the "moons" of other planets may have formed as a result of one of two processes. The first way is their collection from the distributed dust and gas and their further attraction to the planet by its gravitational field. The second way - our other systems could simply be celestial bodies flying by, accidentally caught in the field of attraction. Scientists believe that this is how Mars had two satellites called

How was the moon formed?

But the characteristics of the moon cannot be explained by these two options. Astronomers are sure that it appeared as a result of a powerful cataclysm in the solar system. As a result, a huge amount of space debris and young planets were formed, which were worn in space. And one of these celestial bodies collided with the Earth. Several debris of the Earth was thrown into the surrounding space. Some of them gradually began to gravitate and formed the moon.

Moon compared to satellites of other planets

The moon is a fairly large satellite. Only such satellites of other planets as Io, Callisto, Ganymede, Titan surpass it in size. Thus, the size of the moon allows this celestial body to take fifth place among 91 satellites of the entire solar system.

The appearance of the moon and its surface

The lunar surface is subject to very little change. After all, the era of active meteor showers remained for her in the distant past. There is also no tectonic or volcanic activity on the surface of the Earth's satellite. The moon does not have a dense atmosphere and water, which are also two more reasons why the lunar appearance remains unchanged for humans. Continental areas on the lunar surface differ more light color... They are a large number of craters. It used to be thought that they could be of volcanic origin, but now the theory of meteorites prevailed. On the moon were found their mountains, crevices, gorges.

The lunar mountains are called the same as the terrestrial ones. Here you can see the Carpathians, the Alps, and the Caucasus. Such names were also given to them by Galileo. And the seas are named after the old belief that the Moon rules human emotions and the weather on Earth. For example, on the satellite map, you can see the Sea of ​​Tranquility, Crises, Rains, Clarity, as well as the Ocean of Storms.

Amazing coincidences

In the structure of the solar system, scientists have found many amazing coincidences. One of them is the following: all other planets of the system can fit between the Earth and the Moon. The distance from the satellite to the Earth is about 384,400 km. In other words, the Moon is not that far from the Earth. NASA specialists decided to figuratively "push" all the remaining planets into the gap between the Moon and the Earth. To the surprise of astronomers, they fit there almost exactly, with only small gaps.

Now scientists can only guess whether this fact is a coincidence or not. Moreover, this wonderful case is not the only one. The size of the moon is chosen in a very special way, and the distance from the sun, it would seem, is measured with an accuracy of a centimeter. After all, if the Moon is between the Earth and the Sun, then it completely blocks it. So it turns out solar eclipse... If the size of the moon were slightly larger or, conversely, smaller, people would not be able to observe this amazing natural phenomenon.

Angular size of the moon

It is, simply, its apparent size from the surface of the Earth. For example, the angular size of the satellite of our planet and the Sun is about the same, because it seems to people that these celestial bodies are equal. But in fact, the linear dimensions of the Moon and the Sun differ by almost 400 times. Another surprising coincidence can be observed here.

The sun is about 400 times the size of the Earth's satellite. But the Moon is 400 times closer to the Earth than the Sun. The radius of the solar system luminary is about 696 thousand km. The size of the moon, more precisely, its radius is 1737 km. This situation is the only one in the entire solar system. This fact is especially surprising when you consider that there are 8 planets and 166 satellites in the solar system. As a result of this coincidence, the apparent sizes of the Moon and the Sun are practically the same.

The moon and life on earth

The moon not only made the appearance of the starry sky different for the inhabitants of the Earth. This celestial body also made the emergence of life on our planet most likely. The fact is that each planet oscillates during rotation, because of this, the climate on other planets is constantly subject to changes. With any unstable climate of nascent life, it is very difficult to gain a foothold on a celestial body. The size of the moon is not small enough to have no effect on the climate. The moon helps to soften the vibrations of the Earth as it rotates.