Why is the Moon moving away from us? What is the maximum distance the Moon can move from the Earth? Why did the moon move away from the sun?

Origin of the Moon. It was a long time ago. So long ago that it’s hard to even imagine. To determine the number of years that have passed, you would have to write a number with nine zeros.

At that time, the Moon and Earth were one. The huge molten ball made one revolution around its axis in just four hours. The centrifugal force at the equator and the tides that the Sun caused in this ball elongated in its direction came into resonance with the ball’s own vibration and tore off a piece from it, which eventually became the Moon.

At the site of this detachment, the greatest depression on Earth, now occupied by the Pacific Ocean, has remained to this day.

This is what the famous English astronomer believed George Darwin(1845–1912), son Charles Darwin(1809–1882). And, despite the fact that his hypothesis about the origin of the Moon is not now generally accepted, observations and calculations show that two billion years ago our natural satellite was at a very close distance from the Earth.

But our planet and the Moon are 4.5 billion years old (this is also evidenced by the age of the oldest lunar rocks). If the Earth and Moon had appeared together at that moment, they would have moved significantly further away from each other than they do now.

What happened during the first half of their existence? Where was the moon? Maybe they formed together, but earlier the Moon was moving away from our planet less intensely than it is now? Or maybe somewhere it revolved around the Sun as a planet, and then, due to some circumstances, was captured into low-Earth orbit and became a satellite of the Earth?

These questions, together with Darwin’s version, reflect three hypotheses of the origin of the Moon, which have been quite popular in science for a long time: 1) separation from the Earth, 2) its formation at the same time as our planet, and 3) capture of a ready-made satellite.

In 1975, another, catastrophic hypothesis appeared, which connects the origin of the Moon with the collision of the Earth with a large cosmic body comparable in mass to the planet Mars.

Let us briefly dwell on these hypotheses and analyze them, taking into account the main physical characteristics of our natural satellite. Along with the size and mass, the most important parameter of a planet is its average density, which allows us to determine its chemical composition. For the Moon it is 3.3 g/cm 3 (for the Earth 5.5 g/cm 3). The lunar density is close to the density of the Earth mantle, lithosphere The Earth, its rocky shell, which occupies 70% of the planet’s mass - from the iron-nickel core (half the Earth’s radius) to the surface. As for the Moon, it has a very small iron-nickel core, only 2–3% by mass (Fig. 2).

1) It would seem that if the lunar substance is similar to the substance of the earth’s mantle, then this is a convincing argument that the Moon at one time broke away from the Earth. Based on this, the hypothesis of the separation of the Moon from the Earth (jokingly called “daughter”) was very popular at one time and was generally accepted at the beginning of the twentieth century.

In favor of this version of the origin of the Moon, a similar ratio of oxygen isotopes 16 O, 17 O and 18 O was obtained relatively recently in lunar rocks and rocks of the Earth’s mantle. However, in addition to the similarity of the lunar substance with the substance of the earth's mantle, there are also significant differences.

Indeed, the so-called volatile (low-melting) and siderophilic There are significantly fewer elements in lunar rocks than in terrestrial rocks. In addition, for centrifugal force and tide to tear off a piece of the globe, a period of its rotation of at least 2 hours is required so that the half-period of rotation would resonate with the period of natural oscillations of this ball (about an hour), and the mass of the torn piece, as calculations show, should make up 10–20% of the Earth's mass.

In fact, the mass of the Moon is 81 times less than the mass of the Earth, and the mass of the mantle material in the volume of the Pacific Trench would be only a small fraction of the mass of the Moon. In addition, the age of the Pacific Ocean is estimated to be about 500 million years, while the age of the Moon and Earth is 4.5 billion years. Thus, the hypothesis of the separation of the Moon from the Earth does not withstand the strict criticism of specialists.

2) If the Moon and Earth were simultaneously formed from the same ring protoplanetary clouds (jokingly - a “sister” hypothesis), this easily explains the identity of the oxygen-isotopic ratio of their substance, but does not agree with its difference in density and with a deficiency of iron and siderophile and volatile elements.

One of the authors of the impact hypothesis V. Hartman wrote: " It is difficult to imagine that two celestial bodies grow side by side from the same orbital layer of matter, but at the same time one of them takes all the iron, while the other remains practically without it».

3) Legends of some peoples (for example, Dogon, West Africa) tell about the time when there was no Moon in the sky, and about the appearance of a new star. Contrary to this, the results of computer simulations of the capture of the Moon by the Earth (jokingly called the “marital” hypothesis) show that the likelihood of such a capture is very small.

Much more likely is a collision or ejection of the proto-moon by Earth's gravity beyond the Earth's orbit. The Moon's low density and small iron core could be explained by the assumption that it formed outside the terrestrial planets (Mercury, Venus, Earth and Mars), but in this case it is impossible to explain the deficiency of volatile elements, which are abundant there. It is difficult to find a place in the solar system with both a low content of one and the other.

4) One of the main goals of the American space missions to the Moon in the 1960s and 70s was to find evidence in favor of one or another of the three above

named hypotheses of the origin of the Moon. During the Apollo program, 385 kg of lunar material was delivered to Earth. Already his first analyzes revealed significant disagreements between the results obtained and all three hypotheses.

Most experts believe that the available currently facts testify in favor of a hypothesis that did not yet exist before the flight spaceships to the Moon - hypotheses of a catastrophic collision. To explain the iron deficiency on the Moon, we had to make the assumption that at the time of the collision (4.5 billion years ago) gravitational pull had already occurred in the depths of both bodies. differentiation substances when heavy chemical elements sank down and formed the core, and the lighter ones floated to the surface and formed the mantle, crust, hydrosphere And atmosphere.

This assumption has no geological justification, but, nevertheless, the catastrophic hypothesis of the origin of the Moon is now considered the most acceptable.

Evolution of the Earth-Moon system. Let us now consider how the Earth and the Moon have coexisted since fate brought them together. Home driving force their interaction was and remains tidal friction. The tidal force on Earth is the resultant of two forces: the attraction of the Moon or Sun and the centrifugal force of the Earth's rotation around the common Earth-Moon center (called barycenter system and is located in the Earth’s mantle at a depth of 1700 km) or Earth-Sun (Fig. 3).

At the center of the Earth these forces balance each other, but at the point A attraction prevails, and at the point IN- centrifugal force. These are the points of maximum tide on the surface of the planet.

Due to the daily rotation of the Earth in places of tidal protrusions A And IN visits the same point on the earth's surface twice a day. Residents of coasts and islands are well aware of the tides, when the water rises and falls twice a day. In some places, due to a combination of circumstances (current direction, narrow bays and river mouths), the height of the sea tide reaches 10 m, and, for example, at the mouth of the Severn River or in the Bay of Fundy (England) it reaches 16 m.

But tides are not only observed in the ocean. The solid Earth, attracted by the Moon and the Sun, behaves like a spring and is deformed, i.e. the solid body of the Earth also experiences a tide. These phenomena are called earth tides . The highest height of the earth's tide at the equator is 55 cm, and at the latitude of Kyiv - about 40 cm. It is to this height that we rise and fall twice a day, slowly and continuously, 6 hours up, 6 hours down.

Since there is no fixed reference point against which such movements could be observed, this phenomenon remains unknown to many. But high-precision instruments (gravimeters, tiltmeters) reliably record the earth's tides. In this case, the observation point moves away from the center of the Earth by only one ten-millionth of the Earth’s radius (Earth’s radius ≈ 6400 km).

Gravimeters record this movement as a decrease in gravity, because gravity decreases with increasing distance from the center of the Earth.

During tides, both in the ocean and in the earth's firmament, due to the viscosity of the substance and the friction of water along the bottom and shores of reservoirs, part of the energy of the rotational movement of the Earth is dissipated in the form of heat. Tidal protrusions from friction A And IN do not have time to fall quickly and are carried forward by the Earth in the course of its rotation (Fig. 3). Moon's attraction to the ledge A(more than protrusion IN) slows down the daily rotation of the Earth, and gravity protrudes A Moon (more than a ledge IN) spins our natural satellite in orbit.

Due to the first effect, the Earth slows down its rotation around its axis, and due to the second, the Moon moves away from the Earth. True, the figures that describe the increase in the day and the lengthening of the radius of the Lunar orbit are extremely small: the day increases by 0.002 s per 100 years, and the Moon moves away from the Earth by 3 cm/year. Laser determinations of the distance to the Moon, carried out in 1969–2001 using corner reflectors installed on the Moon, give a value of 3.81 ± 0.07 cm/year for increasing the radius of the lunar orbit.

These seemingly insignificant quantities cause significant changes on a cosmological time scale. In addition, when the Moon was closer to our planet, their interaction was more intense: the days on Earth increased more significantly, and our natural satellite moved away faster (Fig. 4).

This is confirmed not only by the results of astronomical observations. There are also paleontological, fossil evidence suggests that days on Earth were previously shorter.

During the growth process, some corals and mollusks, as well as algae, form not only annual rings, as is the case with trees, but also daily rings. Using these data, you can calculate the number of days throughout the year. Modern organisms produce 365 diurnal rings in one annual, while fossils produce more.

Thus, organisms living in Devonian period Paleozoic era (400 million years ago, when the first vertebrates—fish) just appeared—accumulated 400 daily layers per year, and those who lived in Proterozoic(670 million years ago) – 435.

Astronomers do not know the reasons that, throughout the history of the Earth, could significantly influence the length of the year - the period of the Earth’s revolution around the Sun. Thus, the year did not change noticeably during this long period of time, only the length of the day changed.

It is easy to calculate from these observations that in Devon the day lasted 22 modern hours, and 670 million years ago ( Proterozoic era) were equal to only 20 modern hours. Previously, the days were even shorter, but there is no paleontological evidence of this at this time.

According to calculations by astronomers who study the origin of planets and the past solar system, the initial period of rotation of the Earth around its axis (day) was 10 hours. The day on the giant planets Jupiter and Saturn is close to this value, the enormous inertia of which and numerous satellites that act inconsistently contributed to the preservation of their primary daily rotation. Uranus and Neptune have slowed down their axial rotation slightly: a day on Uranus lasts about 17 hours, and on Neptune - about 16.

The Earth will slow down its rotation until the day is equal to the period of revolution of the Moon around our planet. Their total rotation period will then be 47 current days. The Earth and the Moon will rotate facing each other with tidal protrusions, on the same side, as if connected by a bridge, like a dumbbell.

By the way, the Moon used to rotate around its axis much faster, and then it was possible to admire not only one side of our satellite. However, the tides that Earth’s gravity causes on the Moon are significantly greater than those caused by the Moon on Earth, since the mass of our planet is 81 times greater, and the force of gravity on the surface of our satellite is 6 times less.

Lunar tides have long slowed down the rotation of the Moon, and its tidal protrusion is now always directed towards the Earth. Such a rotation of the satellite around the central planet and around its axis, when one side of the satellite is always facing the planet, and the period of rotation around the central body and around the axis coincide, is called synchronous.

Surprising in this regard is the foresight of the famous German philosopher Immanuel Kant(1724–1804) at a time when there was no scientific data on this issue yet.

In his work “General History and Theory of Heaven” in 1754, he wrote: “ If the Earth is steadily approaching the moment of suspension of its rotational motion, then the period during which this change occurs will be completed when the surface of the Earth is at rest in relation to the Moon, that is, when the Earth begins to rotate around its axis at that the very time at which the Moon makes a revolution around the Earth, therefore, when the Earth will always face the same side to the Moon. The reason for this state is the movement of a liquid substance covering part of its surface only to a very small depth. This immediately shows us the reason why the Moon, in its rotation around the Earth, always faces it with the same side».

It is curious that the height of the tidal ridge on the Moon is now 2 km. This is 100 times more than the tide that our planet would cause at its current distance from the Moon. Obviously, at the time when such a high tide formed, our natural satellite was significantly closer to the Earth. For such a huge tide, the distance would not be 380 thousand km, as it is now, but 5 times less.

The moon then had molten interiors, which, cooling, hardened and retained this huge tidal protrusion in its body, as a memory of that long-ago era. This also indicates that the Moon began to rotate synchronously with its revolution around the Earth already when the distance between them was only 75 thousand km. This happened less than two billion years ago.

Let us now turn to the Earth. As mentioned, the length of the day and month in the distant future will be equal to each other and will be 47 current days. For this process to be completed, it will take a long time - about 50 billion years. Let us recall that the age of the Earth and planets is about 4.5 billion years.

This would have stabilized the process of joint rotation of the Earth and the Moon, if not for the Sun. The fact is that solar tides also slow down the daily rotation of the Earth. Although they are two times smaller than the lunar ones, they do not change over time.

And if the braking effect of the Moon on the daily rotation of the Earth stops at the moment when the day and month become equal, then the influence of the Sun on this process will continue. As a result, the day on Earth will continue to increase, and as a result, our planet will rotate around its axis more slowly than the Moon around it.

In this situation, the tides caused by the Moon on Earth will affect its rotation in the direction opposite to the previously considered case, i.e. the Earth will accelerate in its rotation, and the Moon will slow down in orbit. The reverse process will begin: the day will begin to decrease, and the Moon will begin to approach the Earth, and this will continue until the Moon approaches the so-called Roche limit.

For a satellite with zero strength (liquid, individual fragments solid) this limit is approximately 1.5 radii from the surface of the central planet. Here, the centrifugal force of the Moon's revolution and the gravity of the planet, acting in opposite directions (their resultant is the tidal force), will prevail over the force of gravity on the surface of the satellite and tear it apart. A ring of many small satellites forms around the Earth.

Such examples are known in our solar system: the giant planets Jupiter, Saturn, Uranus and Neptune all have rings near the surface, although the origin of these rings is not necessarily related to tides. Obviously, the satellites of these planets could not form near the Roche limit.

In the Earth-Moon system, tidal processes occur extremely slowly. It has already been mentioned: for a day on Earth to become equal to the length of a month, it takes about 50 billion years. And for the Moon to return back to the Earth, it takes too long, even in cosmological scale.

In the Solar System there are many examples of the effective effect of tides on the rotational motion of celestial bodies. The planets Mercury and Venus have slowed down significantly as a result of the influence of solar tides on them, and their day (period of rotation around their axis) lasts 58.6 and 243 Earth days, respectively.

The synchronous rotation is followed by the small satellites of Mars Phobos and Deimos. On the large satellite Io, closest to Jupiter, the height of the tide, frozen during synchronous rotation, is 3 km. Only as a result of the satellite moving along an elongated (eccentric) orbit does this height change by 84 meters. Moreover, due to the deformation of the satellite’s body, 10 times more heat is released than on the Moon from the decay of radioactive substances. As a result, Io has volcanoes that are more powerful than those on Earth (Fig. 5).

The large moons of Jupiter, Saturn and Uranus, and Neptune's largest moon Triton, rotate synchronously. Pluto and Charon - shining example tidal capture. In this system, not only Charon rotates synchronously, but Pluto also faces Charon with one side all the time, they rotate with a period of 6.4 days, as if connected by a jumper.

As a result, we emphasize that tidal friction is an important factor in the evolution of cosmic systems, not only planets and satellites, but also multiple star clusters and even galaxies.

Dictionary
Atmosphere(from the Greek ατμος - steam and σφαϊρα - ball) - the air shell of the Earth.
Hydrosphere(from the Greek υδωρ - water and σφαϊρα - ball) - the water shell of the Earth.
Gravimeter(from Latin gravis - heavy and Greek μετρεω - to measure) - a device for measuring the magnitude of gravity.
Devonian(from the name of the English county of Devonshire) – fourth period Paleozoic era from 419 to 359 million years ago.
Differentiation(from Latin differentia - difference) - division of the whole into qualitatively different parts.
Cosmological(from the Greek κοσμοζ - space, universe) - everything that relates to the Universe.
Climax(from Latin culmen – top) – here maximum height luminaries
Lithosphere(from the Greek λιτος - stone and σφαϊρα - ball) - the stone shell of the Earth.
Mantle(from the Greek μαντιον - cover) - the stone shell of the Earth from the core to earth's crust.
Paleozoic(from the Greek παλαιος - ancient ςωη - life) - the third geological era in the history of the Earth from 541 to 251 million years ago.
Paleontology(from the Greek παλαιος - ancient, οντος - essence and λογος - teaching) - the science of the fossil remains of living organisms.
Proterozoic(from the Greek προτερος - previous) - the second geological era in the history of the Earth from 2500 to 541 million years ago.
Protoplanetary, protosolar(from the Greek πρωτος - first) - the primary nebula from which the Sun and planets were formed at one time.
Siderophiles(from the Greek σίδηρος - iron and φίλεω - love) - chemical elements adjacent to iron in the periodic table.
Synchronous(from the Greek συγχρονο - simultaneously) - coincidence in the period of oscillation of two or more processes.
Tectonics(from the Greek τεκτονικη - construction) - the science of the structure and movements of the earth's crust and the masses located under it (lithospheric plates).

I.A. Dychko, candidate of physical and mathematical sciences, Poltava

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Our planet has only one satellite - this. And gradually this celestial body becomes further and further from the Earth. The distance between the Moon and Earth is increasing by about 3.8 centimeters per year. Immediately after its birth, the Moon was much closer to our planet. Scientists estimate this distance at 60,000 kilometers. For clarity, recall that geostationary satellites are in orbit at an altitude of 35,786 kilometers.

If the difference in mass between bodies orbiting each other is very large, another interesting phenomenon arises: orbital resonance. Most clear example- rotation. Because the Sun is much larger, instead of being in a synchronous orbit, Mercury has an orbital resonance of 3:2 (i.e., spins 3 times on its axis for every two revolutions around the Sun).

In the case of Saturn, some of its moons are also in orbital resonance with each other. Titan is in a 3:4 orbital resonance with Hyperion (for every 3 orbits around Saturn, Hyperion makes 4). Ganymede and Europa are in orbital resonance with Jupiter with parameters of 1:2:4 (that is, for every 2 and 4 revolutions of Jupiter, Europa and Ganymede make 1, respectively).

Can the Moon escape from the Earth?

The answer is no. No matter how much she didn't want it. Eventually the Moon will move so far away from the Earth that gravity's deformation can no longer affect our planet's rotation rate. Our satellite will seem to hover over one point on the earth's surface. And it can only be observed from one side of the Earth. Some believe that this will happen only in 50 billion years. It is unlikely that any of us will live to see this event...

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Among all the moons of the solar system, the Earth's satellite is the most unique. Due to its close location to the Earth, as well as its size, the Moon gives our planet a stable and stable position in its eternal path in orbit. That is, it must be said that the Earth-Moon connection maintains its position in outer space in a more or less uniform rotation.

The formation of the Moon occurred approximately 4.5 billion years ago; according to the latest information from scientists, the Moon has become younger, shedding several million years. I must say that the history of the formation of the Moon is amazing. And the Earth’s satellite itself is extremely important for the existence of life on the planet. However, the Earth is also important for finding the Moon in its orbit.

As has been described more than once, billions of years ago, a cosmic object of no less smaller size crashes into a huge protoplanetary substance. It was then, from the molten mass - and this was the Earth - that huge pieces of matter were pulled out from the mass of the planet. Thrown into space, solid rocks are retained by the Earth's gravity.

Trying to escape the captivity of the Earth's gravity, but not having the strength to do this, they begin to gather into one large object. And under the influence of rotational forces, they turn into a ball. So, our Blue Planet has acquired an important component for the education and preservation of life.

It's amazing how precisely in time the space object arrived. No less surprising is the fact that someone’s hand placed both space objects in exactly the position and points where it was necessary for the flourishing of life on Earth.

Before the impact and formation of the Moon, our planet was not yet blue, and rotated 4 times faster than it does now. The Earth's axis stood at an inclination of 10 degrees, and the Earth's day at that time was very short - only 6 hours. And the angle of inclination affected the average temperature on Earth.

At this time, the Moon had not yet entered its current orbit, and was 12 thousand times closer to the Earth. Exerting a strong influence on the planet by powerful gravity. Soon, oceans began to form, and tidal friction began to slow the Earth's rotation. Over the course of 3 billion years, the formation of continents continued, and the speed of rotation of the planet continued to decrease, reaching 18 hours a day. After another half a billion years, the earth's day reaches 222 hours, and by adding seconds per year, it reaches 24 hours.

Why is the Moon so necessary for the Earth?

In fact, the Moon plays a very important role in the life of our planet. Firstly, it is necessary to note the gravitational force of the satellite, acting in conjunction with the Moon-Earth, our planet is in a stable orbit. And also, thanks to the Moon, our Blue Planet received an inclination angle of 23 degrees.

This degree of inclination can be called optimal; nature, as if specially took care of the comfort of human life on Earth. Indeed, thanks to this angle, the planet maintains a rather narrow range of temperatures. The sun's rays emitted by our luminary spread evenly across the globe, which creates for life on Earth good conditions. The stability of sunrises and sunsets is also associated with the Moon on Earth, supporting the changes of seasons that are familiar to us.

The Moon also has a strong influence on the Earth's water basins. The tides ebb and flow, all this passes under the watchful eye of our companion. The Moon also maintains a 4-meter rise in water level at the equator.

What will happen if the Moon moves away from the Earth? What does the Moon's distance threaten the Earth with?

It is impossible to say that the Moon is eternal above the Earth, and it may happen that the Earth’s satellite will occupy a more distant orbit relative to our planet. Or he will completely go on a free voyage through outer space. After all, as you know, the Moon, although by a small amount, is still moving away from the Earth.

Experts have been observing the Moon for almost half a century. The first American astronauts left a reflector on the satellite. This helped to accurately measure the distance between the Moon and the Earth. And on Earth, the satellite was monitored by modern technology.

And experts were able to answer the question of how far the Moon is moving away from the Earth. It turned out that this is about 4 centimeters per year - not such a small amount, considering that the distance is increasing every year. However, this is not a constant amount of removal. As we know, the distance between the satellite and our planet is not constant. Hence the amount of removal is inaccurate.

Periodically, as the Moon moves away, the Earth's axis changes its tilt angle by 2-3 degrees, in one direction or another from the axis. But even this small value of a couple of degrees responds to natural disasters on Earth. And if the chain connecting the Earth and the Moon is broken, then the two space objects, having lost their buoyant attractive force, will simply scatter in the vastness of space. Released as if from a sling.

About 100 thousand years ago, a slight change in the angle of the axis led to the fact that Sun rays began to fall differently. This led to an environmental catastrophe - where forests once flourished, sun-scorched wastelands formed. And as scientists suggest, it could have been the reason for the migration of the ancient inhabitants of the planet from Africa to the North. And in Europe and North America this led to the beginning of an ice age that lasted for millennia.

And if the Moon breaks the Moon-Earth chain, then a time of catastrophe will come on the planet. The truth is very fleeting. Huge masses of water, held by the Moon, will immediately break free and move deep into the planet with a powerful, unrestrained force. Sweeping away and destroying everything in its path, the first to experience this will be the residents of New York and Rio de Janeiro.

In addition, having lost lunar protection, the Earth may fall under the gravitational influence of another planet. And then there is no need to talk about stability on Earth. The planet will have a different inclination, and a changeable one at that. Which will lead to strong temperature changes. There will also be a redistribution of water basins; the level may increase by hundreds of meters.

However, the Earth also has an impact on the Moon, for example, the rotation of our satellite has slowed down to one revolution per month. The Earth also slows down its rotation, this is influenced by the enormous frictional forces of ocean waves on the bottom. In this case, the tidal wave shifts from the point directly facing the Moon.

Much in the life of our planet is connected with the Moon. A lot can be explained from a scientific point of view. However, to answer the curious question - who so accurately adjusted the celestial mechanism, and placed all the cosmic bodies strictly in their places, on this moment no one can.

MOSCOW, June 22 - RIA Novosti. Assumptions that the Moon may leave the orbit of the Earth’s satellite in the future contradict the postulates of celestial mechanics, say Russian astronomers interviewed by RIA Novosti.

Earlier, many online media, citing the words of the general director of the “space” Central Research Institute of Mechanical Engineering, Gennady Raikunov, reported that in the future the Moon could leave the Earth and become an independent planet moving in its own orbit around the Sun. According to Raikunov, in this way the Moon can repeat the fate of Mercury, which, according to one hypothesis, was a satellite of Venus in the past. As a result, according to the general director of TsNIIMash, conditions on Earth may become similar to those on Venus and will be unsuitable for life.

“This sounds like some kind of nonsense,” Sergei Popov, a researcher at the Sternberg State Astronomical Institute of Moscow State University (SAISH), told RIA Novosti.

According to him, the Moon is indeed moving away from the Earth, but very slowly - at a speed of about 38 millimeters per year. “Over a few billion years, the Moon’s orbital period will simply increase by one and a half times, and that’s all,” Popov said.

“The moon cannot completely leave. She has nowhere to get the energy to escape,” he noted.

Five week day

Another traffic police officer, Vladimir Surdin, said that the process of the Moon moving away from the Earth will not be endless; it will ultimately be replaced by an approach. “The statement “The Moon can leave the Earth’s orbit and turn into a planet” is incorrect,” he told RIA Novosti.

According to him, the removal of the Moon from the Earth under the influence of tides causes a gradual decrease in the speed of rotation of our planet, and the speed of the satellite’s departure will gradually decrease.

In about 5 billion years, the radius of the lunar orbit will reach its maximum value - 463 thousand kilometers, and the duration of the earth's day will be 870 hours, that is, five modern weeks. At this moment, the speed of rotation of the Earth around its axis and the Moon in orbit will become equal: the Earth will look at the Moon with one side, just as the Moon is now looking at the Earth.

“It would seem that tidal friction (the braking of its own rotation under the influence of lunar gravity) should disappear. However, solar tides will continue to slow down the Earth. But now the Moon will outstrip the Earth’s rotation and tidal friction will begin to slow down its movement. As a result, the Moon will begin to approach On Earth, however, it is very slow, since the strength of solar tides is small,” the astronomer said.

“This is the picture that celestial-mechanical calculations paint for us, which today, I think, no one will dispute,” noted Surdin.

Losing the Moon won't turn Earth into Venus

Even if the Moon disappears, it will not turn the Earth into a copy of Venus, Alexander Bazilevsky, head of the laboratory of comparative planetology at the Vernadsky Institute of Geochemistry and Analytical Chemistry of the Russian Academy of Sciences, told RIA Novosti.

“The Moon’s departure will have little effect on the conditions on the Earth’s surface. There will be no ebbs and flows (they are mostly lunar) and the nights will be moonless. We’ll survive,” the agency’s interlocutor said.

“The Earth may follow the path of Venus, with terrible heating, because of our stupidity - if we bring it with emissions of greenhouse gases to a very strong heating. And even then, I’m not sure that we will be able to ruin our climate so irreversibly,” the scientist said.

According to him, the hypothesis that Mercury was a satellite of Venus, and then left the satellite’s orbit and became an independent planet, was indeed put forward. In particular, American astronomers Thomas van Flandern and Robert Harrington wrote about this in 1976, in an article published in the journal Icarus.

“Calculations have shown that this is possible, which, however, does not prove that it was so,” Bazilevsky said.

In turn, Surdin notes that “later work practically rejected it (this hypothesis).”

At any given moment in time, the Moon is no closer than 361,000 and no further than 403,000 kilometers from the Earth. The distance from the Moon to the Earth changes because the Moon rotates around the Earth not in a circle, but in an ellipse. In addition, the Moon is gradually moving away from the Earth by an average of 5 centimeters per year. People have been observing the gradually decreasing Moon for many centuries. The day may come when the Moon will break away from the Earth and fly into space, becoming an independent celestial body. But this may not happen. The balance of gravitational forces holds the Moon firmly in low Earth orbit.

Interesting fact: The Moon moves away from the Earth by about 5 centimeters every year.

Why is the Moon moving away from the Earth?

Any moving body wants, by inertia, to continue its path in a straight line. A body moving in a circle tends to break away from the circle and fly tangentially to it. This tendency to break away from the axis of rotation is called centrifugal force. You feel the centrifugal force in a children's park, riding on a high-speed swing, or when driving a car, when it turns sharply and pushes you against the door.

The word "centrifugal" means "running from the center." The moon also strives to follow this force, but it is held in orbit by the force of gravity. The Moon remains in orbit because the centrifugal force is balanced by the force of Earth's gravity. The closer to a planet its satellite is, the faster it rotates around it.