The moon is farthest from the earth. What is the maximum distance the moon can be from the earth? Evolution of Methods for Measuring the Distance to the Moon
We know the structure of the solar system, where in the center is our Sun, the source of energy and life on Earth. The sun is huge, in terms of mass it is approximately equal to 333,000 Earth masses, in a radius of 109 Earth radii. All planets revolve around the Sun and almost every planet has its own satellites. Our Earth is the third planet from the Sun and has one natural satellite - the Moon. This Earth-Moon pair formed approximately 4.5 billion years ago.
There are three hypotheses of the origin and origin of the Moon:
1 Hypothesis:
It was put forward by J. Darwin at the end of the century. According to this hypothesis, the Moon and the Earth initially made up one common molten mass, the rotation speed increased as it cooled and compressed, as a result, this mass was divided into two parts. Small - the Moon, large - the Earth. This hypothesis explains the low density of the Moon, formed from the outer layers of the original mass. But there is a serious objection from the point of view of the existing geochemical differences between the rocks of the Earth's shell and the lunar rocks.
2 Hypothesis:
The capture hypothesis, developed by the German scientist K. Weizsacker, the Swedish scientist H. Alfven and the American scientist G. Urey, assumes that the Moon was originally a small planet, which, when passing near the Earth, became a satellite of the Earth as a result of the influence of the Earth's gravity.
The probability of such an event is very small, and, moreover, in this case one would expect a greater difference between terrestrial and lunar rocks.
3 Hypothesis:
According to the third hypothesis, developed by Soviet scientists - O. Yu. Schmidt and his followers in the middle of the 20th century, the Moon and the Earth were formed simultaneously by combining and compacting a large swarm of small particles. But the Moon as a whole has a lower density than the Earth, so the substance of the protoplanetary cloud should have been separated with a concentration heavy elements in the earth. In connection with this, an assumption arose that the Earth was the first to form, surrounded by a powerful atmosphere enriched in relatively volatile silicates; during subsequent cooling, the substance of this atmosphere condensed into a ring of planetesimals, from which the Moon was formed.
The last hypothesis at the current level of knowledge (70s of the 20th century) seems to be the most preferable.
At present, the Moon is at a distance of 3.844 * 108 m from us. The measurement results show that the Moon is moving away by an average of 4 cm annually, and this leads to a slowdown of the Moon around the Earth. Therefore, it can already be assumed that over time the Moon will become closer to the Sun and the first to fall into its hot embrace.
An astronomer from the United States, Lee Anna Wilson from the University of Iowa, studying the fate of the Moon, calculated that over time, she would make one revolution around the Earth not 27.32 days, as it is now, but for a long time. The orbit of the Moon will be disturbed, it will be attracted faster by the Sun, weaker by the Earth until it hits a point where the forces of gravity and the forces of attraction of the Sun will tear it apart. The moon will crack and fall apart, i.e., our satellite will end its existence in the form of a ring of debris revolving around the Earth. This ring will be similar to the ring of Saturn.
According to preliminary estimates of scientists, this ring will not live long and at the end it will “rain”, that is, it will fall on our Earth - first small particles, and then those that are larger.
If it really comes to this, then our Earth will follow the Sun, but others are possible. alternatives. The Earth, having lost its satellite - the Moon, will revolve around the Sun for years alone. And much depends on the luminary itself - the Sun, because it will also change all the time. All these options are hypothetical, and we suppose to look at this fact from the other side.
Let's start with the fact that back in 1695, the great scientist Edmund Halley noticed that the records that were left by earlier scientists about the time and place of solar eclipses did not match the calculated ones. Halley, using modern information about eclipses, the movement of the Moon and the Sun, referring to the new universal law of gravitation by Isaac Newton (1687), calculated
the exact places and times where eclipses should have occurred in antiquity, and then compared the results with data on eclipses that were actually observed more than 2000 years earlier. As it turns out, they didn't match. Halley had no doubts about the validity of Newton's law of gravity and resisted the temptation to conclude that the force of gravity had changed over time. Instead, he made the assumption that the length of the Earth's day must have increased slightly since then.
If the rotation of the Earth really slowed down a little, then in order to maintain the total angular momentum in the Earth-Moon system, it is necessary for the Moon to receive an additional angular momentum. Such a transfer of angular momentum to the Moon corresponds to its movement along a weakly unwinding spiral with a gradual removal from the Earth and with a corresponding deceleration of the orbital motion. If 2000 years ago the Earth's day was indeed a little shorter, the Earth rotated a little faster around its axis, the Moon's orbit was a little closer, and the Moon moved along it a little faster, then the theoretical predictions and historical observations of the replacements coincide. Scientists soon realized that Halley was right.
What can cause such a slowdown in the Earth's rotation? These are the ebb and flow. Ebb and flow
The gravitational influence of the Earth on the Moon and vice versa is quite large. Different parts of, say, the Earth are subjected to the attraction of the Moon in different ways: the side turned towards the Moon is to a greater extent, the reverse side is to a lesser extent, since it is farther from our satellite. As a result, different parts of the Earth tend to move towards the Moon at different speeds. The surface facing the Moon swells, the center of the Earth shifts less, and the opposite surface lags behind altogether, and a bulge also forms on this side - due to "lag". The earth's crust is reluctant to deform; we do not notice tidal forces on land. But about the change in sea level, about the ebb and flow, everyone heard. Water succumbs to the influence of the moon, forming tidal humps on two opposite sides of the planet. Rotating, the Earth "substitutes" the Moon with its different sides, and the tidal hump moves along the surface. Such deformations earth's crust cause internal friction, which slows down the rotation of our planet. It used to spin much faster. The moon is even more affected by tidal forces, because the Earth is much more massive and larger. The speed of rotation of the Moon has slowed down so much that it obediently turned to our planet on one side, and the tidal hump no longer runs along the lunar surface.
The impact of these two bodies on each other will lead in the distant future to the fact that the Earth, in the end, will turn to the Moon with one side. In addition, tidal forces caused by the proximity of the Earth, as well as the influence of the Sun, slow down the movement of the Moon and its orbit around the Earth. The slowdown is accompanied by the removal of the Moon from the center of the Earth. As a result, this can lead to the loss of the moon ...
During the expeditions of the Apollo mission to the Moon in 1969-1972, 3 laser reflectors were placed on the surface of the moon. Since then, scientists have become available a way to very exact definition distance to our satellite. If we send a powerful laser signal from the earth to the lunar reflector and measure the time after which it will return with sufficient accuracy, then we can determine the distance to the Moon with an error not exceeding one centimeter. According to such experiments, the Moon is moving away from the Earth by 3.8 centimeters per year. Like this.
The ancient age of the Moon also raises doubts in connection with another parameter of its orbit - the inclination. Currently, it varies from 18 to 28 degrees. And what was the initial inclination of the lunar orbit in the case of the removal of the Moon from the Earth within 4.6 billion years? To simplify the problem, we assume that the Moon simultaneously rotates around two mutually perpendicular axes - the axis of rotation of the Earth (equatorial rotation) and the axis coinciding with the Earth's equatorial diameter (polar rotation). Tidal friction affects the change in these orbits in different ways - the radius of polar rotation, unlike the radius of equatorial rotation, does not increase, but decreases (about 30 times slower). This means that while the equatorial rotation radius has increased by more than 300 thousand km, the polar radius has decreased by almost 10 thousand km and initially was about 130-190 thousand km. If the Moon had formed 4.6 billion years ago, it would have originally been in a very high polar orbit around the Earth.
The launch of an artificial satellite of the Earth into a polar orbit requires much more energy than a similar launch into an equatorial orbit (which is why they try to build spaceports closer to the equator), because. high equatorial speed somewhat reduces the speed at which it is necessary to accelerate the launched object.
In the case assumed by the official version of the formation of the Moon, the equatorial velocity of the Earth was 6 times higher than now (the angular momentum of the Moon is tens of times greater than that of the Earth, which gives the duration of the Earth's day at the time of the formation of the Moon about 4 hours). This allowed the authors of the hypothesis to significantly reduce the mass of the impactor, and, accordingly, its size to a Mars-like level. If 4.6 billion years ago the Moon's orbit was polar, then the advantages of the high equatorial velocity of the Earth disappear, and again there is a need for a significant increase in the mass of the impactor. To avoid this, the authors of the hypothesis significantly increase the initial inclination of the Earth's axis of rotation, as a result of which the ejection of matter occurs in the equatorial plane, and the Moon is in a high polar orbit. However, at the same time, it remains unclear what subsequently forced the Earth to change the angle of inclination of its rotation axis so drastically.
However, the problems with the polar orbit of the Moon do not end there. Such an orbit also implies the Moon's own rotation immediately after its formation around a completely different axis than the one around which it now rotates! The moon should have rotated almost perpendicular to the current axis of its rotation. What forces forced it to stop rotating around this axis? Even if we assume that in the future it changed the inclination of the axis of rotation due to tidal friction, then, all the same, there should have been a significant inclination of the axis of rotation of the Moon with respect to the modern orbit of the Moon, which is not there, otherwise we would have been able to observe the Moon from all sides .
In every this moment 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 revolves around the Earth not in a circle, but in an ellipse. In addition, the Moon is little by little moving away from the Earth by an average of 5 centimeters per year. People have been observing the gradually decreasing moon for many centuries. A day may come when the Moon will break away from the Earth and fly away into space, becoming an independent celestial body. But this may not happen. The balance of gravitational forces keeps the Moon firmly in 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 at the playground, on the high-speed swings, or when the car swerves sharply and pushes you against the door.
The word "centrifugal" means "running away from the center". The moon also strives to follow this force, but it is kept in orbit by the force of the earth's gravity. The moon stays in orbit because the centrifugal force is balanced by the earth's gravity. The closer to the planet its satellite is, the faster it revolves around it.
MOSCOW, June 22 - RIA Novosti. Assumptions that the Moon in the future may leave the orbit of the Earth's satellite contradicts the postulates of celestial mechanics, Russian astronomers interviewed by RIA Novosti say.
Earlier, many Internet media, citing the words of Gennady Raikunov, director general of the "space" Central Research Institute of Mechanical Engineering, 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, the conditions on Earth may become similar to those of Venus and will be unsuitable for life.
"It sounds like some kind of nonsense," Sergei Popov told RIA Novosti. Researcher State Astronomical Institute named after Sternberg Moscow State University (GAISh).
According to him, the Moon is really moving away from the Earth, but very slowly - at a speed of about 38 millimeters per year. "In a few billion years, the period of the Moon's revolution will simply increase by a factor of one and a half, and that's all," Popov said.
"The moon cannot completely leave. She has nowhere to get energy in order to escape," he said.
Five week day
Another employee of the SAI Vladimir Surdin said that the process of moving the Moon away from the Earth would not be endless, eventually it would 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 the tides causes a gradual decrease in the speed of rotation of our planet, and the speed of the departure of the satellite will gradually decrease.
In about 5 billion years, the radius of the lunar orbit will reach 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 speeds of rotation of the Earth around its axis and the Moon in orbit will become equal: the Earth will look at the Moon on one side, just as the Moon is now looking at the Earth.
“It would seem that tidal friction (the deceleration of its own rotation under the influence of lunar gravity) should disappear in this case. However, solar tides will continue to slow down the Earth. But now the Moon will be ahead of the Earth’s rotation and tidal friction will begin to slow down its movement. The Earth, however, is very slow, since the strength of solar tides is small," the astronomer said.
“Such a picture is drawn to us by celestial-mechanical calculations, which no one, I think, will dispute today,” Surdin noted.
The loss of the moon will not turn the Earth into Venus
Even if the Moon disappears, this will not turn the Earth into a copy of Venus, Alexander Bazilevsky, head of the laboratory for comparative planetology at the Vernadsky Institute of Geochemistry and Analytical Chemistry of the Russian Academy of Sciences, told RIA Novosti.
"On the conditions on the surface of the Earth, the departure of the moon will have little effect. There will be no ebb and flow (they are mostly lunar) and the nights will be moonless. We will survive," the agency's source said.
“On the path of Venus, with a terrible warming up, the Earth can go because of our stupidity - if we bring it with greenhouse gas emissions to a very strong warming up. 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 orbit of the satellite and became an independent planet, was really 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 works have practically rejected it (this hypothesis)."
Since 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 is it far to fly there and what is the distance to 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 with the usual methods used in ordinary life. Therefore, the distance to the earth's satellite was calculated using trigonometric formulas.
Like the Sun, the Moon experiences constant motion in 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 in general terms on the ecliptic, differing from it only by 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 daily rotation Earth. But besides that, the Moon moves through 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 just 29 days (lunar month). This difference became the stimulus for breaking down the ecliptic into 12 zodiac constellations (in one month the Sun moves 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's motion, the factor of the strong elongation of the orbit is also added. The eccentricity of the Moon's orbit is 0.05 (for comparison, this parameter for the Earth 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.
During the day, the Moon shifts relative to the stars by 13 degrees, and by about 0.5 degrees per hour. Modern astronomers often use lunar occultations 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 constant and stable. Due to the relatively small mass of the Moon, it is subject to constant perturbations from more massive objects in the Solar System (primarily the Sun and the Moon). In addition, the Moon's orbit is affected by the oblateness of the Sun and the gravitational fields of other planets in the Solar System. As a result, 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. A supermoon is an astronomical phenomenon in 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 also observed: by about 18 arc minutes every 19 years.
What is equal to
Spacecraft will have to spend a lot of time flying to the earth's satellite. You cannot fly to the Moon in a straight line - the planet will orbit away from the destination, and the path will have to be corrected. At an escape velocity 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 the 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 been able to achieve.
The notorious American moon flight in 1969, according to official figures, took 76 hours. NASA's New Horizons spacecraft was the fastest to reach the moon in 8 hours and 35 minutes. True, he did not land on the planetoid, but flew past - he had a different mission.
Light from the Earth to our satellite will get very quickly - in 1.255 seconds. But flying at light speeds is still in 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 drive a 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, then the flight to it would last about 20 days.
How ancient Greek astronomers calculated the distance to the moon
The Moon was the first celestial body to which it was possible to calculate the distance from the Earth. It is believed that astronomers in ancient Greece were the first to do this.
They tried to measure the distance to the moon from 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 closer to the sun 20 times (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 to 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. ancient world. Regular solar eclipses by this time, they 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 (actually, about 400 times).
To calculate the size of the Sun and Moon relative to the Earth, Aristarchus used a different method. We are talking about observations of 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 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 by 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 differences in the maximum height of the Sun above the horizon in Aswan and Alexandria during the summer solstice, determined that the radius of the Earth is close to 6287 km (the modern value is 6371 km). If we substitute this value into Aristarchus' estimate of the distance to the Moon, then it will correspond to approximately 502 thousand km (the modern value of the average distance from the Earth to the Moon is 384 thousand km).
A little later, the mathematician and astronomer of the 2nd century BC. e. Hipparchus of Nicaea calculated that the distance to the earth's 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, you can find the ratio of the distances to the Sun and to the Moon. 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 greater than 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 3,483 times smaller than the distance to it - this information was known to everyone at 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= 232 or S l = 232R l.
Accordingly, the distance to the Moon is 232 * R s / 2.5 = 60 radii of the Earth. It turns out 6 371 * 60 = 382 260 km. Most interestingly, 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 with the help of laser instruments, which make it possible to measure it with an accuracy of several centimeters. In this case, the measurements take place in a very short time - no more than 2 seconds, during which the Moon moves away in orbit by about 50 meters from the point where the laser pulse was sent.
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 for the parameters of the Moon's orbit and the correspondence of its size to the size of the Earth.
A more accurate method of measuring the distance to the moon appeared in connection with the development of radar. The first radiolocation 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 location. To implement it, several corner reflectors were installed on the Moon in the 1960s. It is interesting to note that the first experiments on laser ranging were carried out even before the installation of corner reflectors on the surface of the Moon. 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, astronauts of the Apollo program delivered three corner reflectors to the surface of our satellite. Among them, the reflector of the Apollo 15 mission was the most perfect, since it consisted of 300 prisms, while the other two (the Apollo 11 and Apollo 14 missions) only had a hundred prisms each.
In addition, in 1970 and 1973, the USSR delivered two more French corner reflectors to the lunar surface aboard the Lunokhod-1 and Lunokhod-2 self-propelled vehicles, each of which consisted of 14 prisms. The use of the first of these reflectors has a remarkable history. During the first 6 months of operation of the lunar rover with a reflector, it was possible to conduct about 20 sessions of laser location. However, then, due to the unfortunate position of the lunar rover, it was not possible to use the reflector until 2010. Only pictures of the new LRO apparatus helped to clarify the position of the lunar rover with the reflector, and thereby resume work sessions with it.
In the USSR, the largest number of laser ranging sessions were carried out on 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 the observations were discontinued due to the curtailment of the Soviet lunar program.
In total, from 1970 to 2010, approximately 17,000 high-precision laser location sessions were conducted in the world. Most of them were associated with the Apollo 15 corner reflector (as mentioned above, it is the most advanced - with a record number of prisms):
Of the 40 observatories capable of performing laser ranging of the Moon, only a few can perform high-precision measurements:
Most of the ultra-precise measurements were made with the 2-meter telescope at the Texas MacDonald Observatory:
At the same time, the most accurate measurements are made by the APOLLO instrument, which was installed on the 3.5-meter telescope at 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. By now, 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 trapped). 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 the Earth's rotation around its axis gradually slows down. The speed 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 day will be equal to the lunar month. As a result, the Moon and Earth will always face each other with only one side, as is now observed in the Pluto-Charon system. By this time, the Moon will move away to approximately 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 accelerate the process of the Moon's removal (the 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 tidal interaction with each other. When approaching the Earth at 12 thousand km, the Moon will be torn apart by tidal forces, the debris of the Moon will form a ring like the known rings around the giant planets of the Solar System. Other known satellites of the Solar System will repeat this fate much earlier. So Phobos is given 20-40 million years, and Triton is about 2 billion years.
Every 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 between the Earth and the Moon.
Between the Earth and the Moon, theoretically, you can place all the planets solar system. If you add up the diameters of all the planets, including Pluto, you get a value of 382,100 km.
