The influence of the Moon on the Earth is difficult to overestimate. In particular, it keeps the Earth at an inclination of 66 degrees from the orbital plane. Thanks to this, the climate in most of our planet is quite good.
It is impossible to predict which side the Earth will turn to the Sun if the Moon leaves to wander through space. Presumably, in the literal sense, it will lie on its side. Glaciers will melt, deserts will freeze, the ebb and flow will be forgotten. To understand how this threatens all living things on the planet, it is enough to watch any apocalyptic film.
Meanwhile, Russian ufologists have already taken the version with the removal of the moon on a pencil and put forward a theory in their own style.
Ufologists have long considered the Moon as the closest base of alien civilizations to us, ufologist Yuri Senkin told Vecherka. - The fact that telescopes, lunar rovers and people who have visited the Moon several times, they were not caught there, is simply explained - we explored only one side of the satellite. The reverse side has not been studied.
It is difficult to say what caused the distance of the Moon, but it is possible that this is the work of hands - or that they have instead of hands - aliens. And even if this is true, it is unlikely that this was done in order to harm our civilization. Alien races may pursue completely different tasks. The moon, for example, is rich in resources, including those that are in terrible shortage on Earth.
The journalists of "Vecherka" were not inspired at all by the prospect of losing the Earth's satellite: firstly, it would be rather boring without it at night, and secondly, they would like to live longer. Therefore, we immediately turned to the State Astronomical Institute named after P.K. Sternberg for clarification.
Head of the Department of the Moon and Planets, Doctor of Physical and Mathematical Sciences Vladislav Shevchenko laughed for a long time after listening to the question. Asked to repeat. And laughed non-stop again.
Oh storytellers! he said breathlessly. - But seriously, the Moon is really moving away from the Earth, but you have to understand that this has been happening for four billion years, since the Moon itself was formed.
According to Shevchenko, the removal of the Earth's satellite is quite natural physical phenomenon- remember school curriculum in physics, called inertia. Imagine that you are riding a carousel. Spinning faster and faster, you feel how you begin to tilt in the direction opposite to the axis of the carousel. And if you do not grab onto something, you can simply be thrown out. But the moon has nothing to cling to. The speed with which it rotates around the Earth sets such inertia that the Earth's gravitational field is powerless to hold this ball. And you need to understand that gravity affects our satellite less and less as it moves away.
According to calculations, the Moon is moving away from the Earth by about 3.8 centimeters per year, continues Vladislav Shevchenko. - Now the distance to it is 384 thousand kilometers. And when the moon was just forming, it was about 60 thousand kilometers. Give a hand! It took about four billion years for this distance to increase six times.
And it will take several million more years for the Moon to move away, ceasing to completely cover the Sun during an eclipse. Therefore, it is too early to worry about this. Just know: when this happens, Vechernyaya Moskva will notify you personally in the first place.
There are several versions of the origin of the Moon, but in recent decades, scientists have leaned towards the theory of a giant collision. It happened about 4.6 billion years ago: the hypothetical planet Theia collided with the Earth at a tangent, tearing a huge piece out of our long-suffering planet. The Earth immediately boiled, almost turning inside out, and the part of it that Theia vomited was captured by the Earth's gravitational field so that, after billions of years, we could lift our heads and say: "The moon is awesome today!"
INTERESTING FACT
Inhabitants of the southern hemisphere see the Moon in reverse: they grow to the left, decrease to the right.
First artificial satellite The sun became the Soviet station "Luna-1" in 1959. Due to an error in the calculations, she is on the second space velocity passed by the satellite of the Earth.
The smartphone that your boy neighbor walks around with is many times more powerful than the computer that controlled the landing of astronauts on the moon.
A natural satellite of our planet and the second brightest object in our sky, the Moon is the most unique of all the moons of the solar system. Due to its size and proximity to the Earth, it provides its stability.
But few people know that the moon is moving away from us. And the further, the faster. And soon the moment may come when it will no longer be able to stabilize the movement of our planet. Without the Moon, an ecological catastrophe will begin on Earth: water will evaporate, and glaciers will melt due to high temperatures. The ocean level will rise by several hundred meters, and people will become accustomed to living in conditions of terrible hurricanes and ferocious storms.
Without the Moon protecting us, life on the planet will simply disappear.
If the Moon moves away only ten percent from its current distance to the Earth, and this is forty thousand kilometers, then there will be no way back. The rotation of our planet will become unpredictably chaotic, which, in turn, will lead to the death of many life forms on it.
It cannot be said that for scientists the distance of the moon was a surprise. For the past more than four decades, they have been watching the satellite very closely. In 1968, the Apollo astronauts left the first instrument equipped with reflectors on the moon. This was done to more accurately measure the distance to the moon using lasers. And it turned out to be very helpful.
So, at present, in the state of New Mexico, there is modern equipment that easily calculates the distance from the Earth to the Moon. It is more difficult to determine how fast the Moon is receding. But this was also found out. Decades of tireless work have shown that the satellite is leaving at a rate of four centimeters per year. It would seem that this is a very small amount, but it is growing year after year.
Many underestimate what the Moon is for our planet, and what its gravity does for us.
Our satellite has the most large mass relative to its planet in the solar system, and thanks to such a mass, it can ensure the stability of our planet. The rotation of the Earth is determined by its gravity - the force that attracts objects. Its value depends not only on the distance between the planet and its satellite, but also on their masses, and since the mass of the Moon is very large, then, accordingly, gravity is also large. At a distance of 800 thousand kilometers, lunar gravity keeps our planet in its orbit. And this is very important for her: the Earth has a stable axis located at an angle of 23 degrees, and therefore, thanks to such a slight tilt, the rays of the Sun spread evenly throughout the globe, maintaining a relatively narrow temperature spectrum on Earth, which is ideal for life.
And as long as the angle of inclination of the earth's axis exists in this value, earthlings will have a comfortable and constant climate system. And it is this stability that makes it possible for all living things on the planet to live and develop.
The change of seasons, which is habitual for a person, is also connected with the tilt of the axis.
And if it weren't for the Moon, the angle of the planet would be unstable, which means that there would be no stable sunsets and sunrises, there would be no summer and winter.
Periodically, the angle of the earth's axis changes by two or three degrees in one direction or another, and as a result, we observe many natural disasters. And what happens when, as a result of a change in the magnitude of gravity, the angle of inclination also begins to change steadily.
About a hundred thousand years ago, a slight drop in the angle of the axis changed the angle of incidence of the sun's rays on Earth, turning our lush forests into a desert. And, probably, this was the reason for the migration of ancient people to the north from Africa, and in North America and Europe, this shift provoked an ice age that stretched for millennia.
And if scientists consider this ice age global event for our planet, it is hard to imagine what will happen to it without the moon. The earth will change beyond recognition, and climates will become unpredictable, presenting people with sharp jumps in temperature.
Lunar gravity also affects the tides. Tidal cycles are repeated twice a day: that is how many times the Earth passes through the expansion zone directed towards the Moon. After all, it is lunar gravity, acting on the surface of the sea, that causes a tide.
Without lunar influence, the four-meter rise in the water level at the equator will disappear, and the water will move deep into the planet, to the continents, which will naturally lead to a rise in sea level. And first of all, New York and Rio de Janeiro will be under attack. Floods will devastate both cities, leaving millions homeless, some of whom will inevitably perish. That's how big the impact of the moon on its planet.
And all of this is not science fiction at all.
The moon, however, is moving away, and when it leaves completely, we - the inhabitants of the planet - will be doomed.
According to the conclusions of the researcher, the Earth and the Moon did not always exist. The moon was created by a cataclysm four and a half billion years ago.
Earth was formed from a protoplanet formed in the solar system. Then it half consisted of a molten mass. One fine day, the still young Earth collided with another planet, close in size to Mars. The impact hit exactly at an angle of 45 degrees,
And when both planets collided, a giant cloud of hard rock fragments formed. The cloud has taken away from the Earth at such a distance that it could move around it in an orbit. Some fragments of the smaller planet did not fall to Earth, but remained in orbit around the Earth, sometimes merging with each other. And as a result, our own Moon began to form very slowly.
Four and a half billion years ago, the Earth rotated four times faster than it does today. A day lasted six hours, and the Earth's axis was tilted only ten degrees.
But in the intervening time everything has changed. And since the Moon used to be much closer to the Earth, it had a stronger gravitational effect on the tides, so the strength of the tides also changed.
The moon formed twelve thousand times closer than it is today. Soon an ocean formed on the planet, and the Moon began to cause friction four times more often. Water was distributed among small volcanic islands, and tidal friction began to reduce the speed of the Earth's rotation.
Over the next three billion years, our continents form, and tidal friction slows the planet down to eighteen hours a day. Half a billion years later, the day is 22 hours long, adding a fraction of a second each year. And as a result, the day reached 24 hours.
In a billion years, lunar gravity could slow down the rotation so much that there would be about thirty hours in a day.
However, gravity also works in the opposite direction. And since the mass of the Earth is greater, then its impact on the Moon is also stronger. The earth in turn slowed down axial rotation Moon up to one rotation per month.
Looking at the moon, we always see the same side facing us. The Earth and the Moon are in the same coupling, bound by gravity.
And it is the gravity of the Earth that has a more tangible effect on the Moon.
As the Earth rotates, friction on the ocean floor slightly shifts the daily tidal wave from the point facing the Moon directly to the east. This volume of water has such an enormous mass that its gravity pushes the Moon forward in its orbit, causing it to move further and further away from the planet. This one is very similar to a pebble tied to a rope: the faster you spin it, the farther it will be from the spinner.
But it is also interesting that the Moon is not only moving away, but also picking up speed. In the Precambrian period, the receding rate was 2 centimeters per year, and today's laser calculations show an increase in speed of up to 3.5 centimeters.
As the moon moves further away, the days will become longer, which means that the change of seasons will be disrupted, which will turn life on Earth into a completely different one.
To more clearly understand what the state of the planet Earth will be like, just look at its close neighbor - Mars.
Mars and Earth have a lot general characteristics: They formed at about the same time. The red color of Mars is due to hematite, a metal that is abundant on Earth. Like Earth, Mars has ice sheets.
In 2004, scientists learned a lot about the Red Planet thanks to the landing on it. Scientists did not find water on the planet, but they found something similar to the former river bed and concretions - small spherical accumulations of intergrown minerals. On our planet, concretions form when water passes through sedimentary rocks, dissolving the minerals, which then form into balls.
Scientists have found large deposits of nodules here on Earth in the desert of southern Utah, trying to understand the past of the planet Mars and the future of our planet. It turned out that the vast desert of Utah was once the bottom of the ocean. And if the concretions on Mars developed similarly, then there was once a lot of water on Mars, which means that life was also possible there. But today Mars is a huge lifeless and waterless space, and scientists do not deny that if water leaves the Earth, it will become the same.
If the gravitational force of the Moon leaves, a new redistribution of ocean water will begin on Earth. True, unlike Mars, the Earth will retain some of its liquid water due to the magnetic poles, but the water will rise hundreds of meters, wreaking havoc throughout the world.
In addition, without the protection of the Moon, the Earth will fall under the gravity of larger planets, such as Jupiter. The stable tilt of the Earth will be a thing of the past. The planet will begin to fill up on its side, and many coastal areas will be flooded. And over time, the situation will only get worse. As the rate of the Moon's receding increases, such a scenario is quite possible.
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Among all moons solar system, Earth's most unique satellite. Due to its proximity to the Earth, as well as its size, the Moon gives our planet a stable and stable position in its eternal journey in orbit. That is, it must be said that the Earth-Moon bond maintains its position in outer space in a more or less uniform rotation.
The formation of the moon occurs approximately 4.5 billion years ago, according to latest information scientists, the moon has become younger, dropping 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 size crashes into a huge protoplanetary substance. That's when, from the molten mass - and it was the Earth - and pulls out huge pieces of matter from the mass of the planet. Thrown into space, solid rocks are held back by the gravity of the Earth.
In an effort to escape from the captivity of the Earth's gravity, but not having the strength to do so, 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 accurately the space object arrived in time. No less surprising is the fact that someone's hand placed both space object exactly in that position and those points where it was necessary for the prosperity of life on Earth.
Prior to the time of the impact and the formation of the Moon, our planet was not yet blue, and rotated 4 times faster than it does now. The Earth's axis was 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 closer to the Earth by 12,000 times. By exerting a strong influence on the planet with powerful gravity. Soon, oceans began to form, and tidal friction began to slow the Earth's rotation. For 3 billion years, the formation of continents continued, and the planet's rotation rate continued to decrease - reaching up to 18 hours a day. After another half a billion years, the Earth's day reaches 222 hours, and adding seconds a year, they reach 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 should be noted the force of gravity of the satellite, acting in conjunction with the Moon-Earth, our planet is in a stable orbit. And also our Blue Planet, thanks to the Moon, received an angle of inclination of 23 degrees.
Such a degree of inclination can be called optimal, nature, as if specially taken care of the comfort of human life on Earth. Indeed, thanks to this angle, a rather narrow temperature range is kept on the planet. The sun's rays emitted by our luminary are evenly distributed over the globe which creates good conditions for life on Earth. The stability of sunrises and sunsets is also associated with the Moon on Earth, supporting the change of seasons we are used to.
The Moon also has a strong influence on the water basins of the Earth. Ebb and flow, all this passes under the watchful eye of our satellite. And also the Moon keeps at the equator a 4 meter rise in the water level.
What happens if the moon leaves the earth. What threatens the Earth with the distance of the Moon.
It is impossible to assert that the Moon is eternal above the Earth, and it may happen that the Earth's satellite will take a more distant orbit relative to our planet. Or even go into free swimming through the expanses of space. After all, as you know, the Moon, although by a small amount, is still moving away from the Earth.
Specialists have been observing the Moon for almost half a century. Even 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 observed 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 value, given that every year the distance is increasing. However, this is not constant removal. As you know, the distance between the satellite and our planet is not constant. Hence the magnitude of the removal is inaccurate.
Periodically, during the distance of the Moon, the earth's axis changes the angle of inclination by 2-3 degrees, in one direction or another from the axis. But even this, a 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 two space objects, having lost their reciprocal attracting force, will simply scatter in the expanses 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 the sun's rays began to fall differently. This led to an ecological catastrophe - where the forests once raged, wastelands scorched by the Sun formed. And as scientists suggest, it could have caused the migration of the ancient inhabitants of the planet from Africa to the North. And in Europe and North America, this did lead to the beginning of the ice age, lasting for millennia.
And if the Moon breaks the Moon-Earth chain, then the time of catastrophes will come on the planet. The truth is very short. Huge masses of water, held by the Moon, will immediately break free, and with a mighty, unrestrained force, move deep into the planet. Sweeping and destroying everything in its path, the first to experience it for themselves will be the residents of New York and Rio de Janeiro.
In addition, having lost lunar protection, the Earth can 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 slope, and changeable. This will lead to large temperature fluctuations. There will also be a redistribution of water basins - the level may increase by hundreds of meters.
However, the Earth also affects 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 forces of friction of ocean waves on the bottom. In this case, the tidal wave is displaced from the point directly facing the Moon.
A lot of the life of our planet is connected with the Moon. A lot can be explained scientifically. However, to answer the curious question - who so accurately debugged the celestial mechanism, and arranged everything space bodies strictly in their places, at the moment no one is able to.
New research by scientist Matthew Huber of Purdue University has shown that over the past 50 million years, the Moon has been moving away from the Earth at an increasing speed. The main reason for this phenomenon, according to the scientist, are the daily cycles of tides on Earth. This process slows down the rotation of the planet around its axis and moves away from the Earth by about 3.8 centimeters per year. Based on these studies, it can be assumed that, subject to the same rate of removal of the Moon over the entire period of its existence, the age of the satellite should be approximately 1.5 billion years. However, it is quite obvious that these calculations are erroneous, since ongoing studies of lunar rocks have shown that the age of the Moon is much greater - almost 4.5 billion years, which implies that the formation of the Earth and our satellite occurred almost simultaneously.
Based on the calculations of Matthew Hubert, it follows that every year the Moon moves away from the Earth by at least 4 cm
By studying the contours of the continents and the bottom of the oceans that existed as early as 50 million years ago, Matthew Huber and colleagues created an accurate model of the ebb and flow of the distant past and calculated the gravitational interaction of the Earth and the Moon. It turned out that earlier the energy of this interaction was half as much as the current one. Therefore, on this stage the moon is moving away from the earth at an accelerating rate. There is no unequivocal opinion about the causes of this phenomenon yet, one of the versions voiced by scientists is the likelihood of the influence of the expansion of the northern part Atlantic Ocean over the past centuries, as a result of which waves are formed very large sizes and high tides pushing the moon much harder.
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Since time immemorial, the moon has been a constant satellite of our planet and the closest to it. celestial body. 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 general terms to 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 to the daily rotation of the 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 is 20 times closer than the Sun (the cosine of an angle equal to 87 degrees is 1/20). The angle measurement error resulted in a 20-fold error, today it is known that this ratio is actually 1 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. It's about observations. 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 to 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 ( contemporary meaning 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. The most interesting thing is that the measurements made with the help of 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 currently 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 of the solar system. If you add up the diameters of all the planets, including Pluto, you get a value of 382,100 km.
