Area of the moon in sq km. Basic indicators of the Earth's satellite: mass of the Moon, diameter, features of movement and research
After establishing the size of the Earth, the next logical question was determining the size of the Moon and the distance to it. This problem was apparently first solved by Aristarchus in the 3rd century BC.
Lunar and solar eclipses always attracted people's attention - of course! - such events are hard to miss! But in addition to the unusualness and beauty of these phenomena, they also carried the most important information about the structure of our world. Let's try, repeating Aristarchus' reasoning, to determine the relative sizes of the Earth and the Moon from the shadow.
Look at the photo - this is a montage of three photographs of the partial lunar eclipse of August 16-17, 2008.
In this image, the shape of the Earth's shadow is very clearly visible and you can quite accurately determine its size at the distance of the Moon. Of course, to determine the size of the shadow it is not at all necessary to photograph it - it is enough to just determine the duration of the total phase of the eclipse, and this can easily be done visually even without the use of any optical instruments. (Alas, Aristarchus could not use this method - there were no exact clocks then...) In fact, the period of revolution of the Moon relative to the Sun (synodic month) is well known (by the way, it is also most accurately determined from observations of eclipses) and is 29. 53 days. The average speed of the Moon relative to the Sun (and the Earth's shadow) will be 0.508°/hour, or approximately the apparent diameter of the Moon per hour. Knowing the duration of the total phase of a lunar eclipse, we can determine the size of the earth's shadow. True, in order to avoid cumbersome calculations, measurements must be carried out during an eclipse when the center of the Moon passes as close as possible to the center of the earth's shadow. This will be the case, for example, with the eclipse on June 15, 2011.
Having determined the size of the Earth's shadow (expressed in diameters of the lunar disk) using one of these methods, we only have to take into account that the shadow has the shape of a cone and its cross-section decreases with distance. The cross-section of the penumbra cone increases and, at the distance of the Moon, the penumbra region has a width approximately equal to the diameter of the lunar disk (see figure), this is explained by the fact that the apparent angular sizes of the Moon and the Sun are equal (this is especially noticeable when observing solar eclipses).
The diagram shows that the diameter of the Earth is greater than the diameter of its shadow by approximately one diameter of the Moon. Well, knowing the real size of the Earth, you can calculate the diameter of the Moon and the distance to it.
So, having printed the above photograph, I measured that the diameter of the earth's shadow d shadow = 180 mm, and the diameter of the Moon's image d l = 65 mm.
then the ratio of the diameters of the Earth and the Moon
D Earth/D Moon =(d shadow +d l)/d l =(180/65)+1=3.77
taking the diameter of the Earth D Earth = 12760 km, we get
D Moon =12750/3.77=3382 km.
Now we can easily determine the distance to our satellite. True, here we will deviate from the methods of ancient Greek astronomers, taking advantage of things unknown in the time of Aristarchus trigonometric expressions. The ratio of the Moon's diameter to its distance is the tangent of the Moon's apparent angular size. Since this angle is small and equal to approximately 1/2 °, we can consider that the tangent of the angle is equal to the magnitude of the angle expressed in radians. Then the distance to the moon
L=D Moon /tan(1/2°)=D Moon *57.3*2=
=114.6*D Moon =30.4* D Earth =30.4*12750=387.6 thousand km
(If we wanted to get even greater accuracy, then we would need to accurately determine the angular size of the Moon - this is not difficult to do, knowing the characteristics of the telescope and camera, and taking into account that the observer is not in the center of the Earth, but in this example some deterioration in accuracy is deliberate allowed to simplify calculations)
Aristarchus, performing the same calculations, believed that the Earth's shadow was exactly twice the size of the Moon, so his estimate was not very accurate. He overestimated the size of the Moon and, accordingly, the distance to it by about 25%, but this result was a great achievement if only because it was obtained scientific methods- as a result of observations and calculations. By the way, just determining the apparent size of the Moon (and we used this value to calculate the distance to it) in ancient times was a difficult task...
Of course, this method is only suitable for an approximate assessment, because the orbits of the Moon and the Earth are elliptical and the distances between celestial bodies change noticeably, but do not forget that we were able to determine the structure of the Earth-Moon system practically without trigonometric calculations and without using any astronomical instruments except the gnomon !
ARISTARCH OF SAMOS
(c.310-230 BC)
Ancient Greek philosopher, mathematician and astronomer of the Alexandrian school. Aristarchus, as is commonly believed, was the first to put forward the hypothesis that the Sun is motionless and is at the center of the universe, and the Earth revolves around it and rotates on its axis. This brought upon him an accusation of impiety from the poet and philosopher Cleanthes, and he was forced to flee from Athens.
The only work of Aristarchus that has reached us is the treatise “On the Sizes of the Sun and the Moon and the Distances to Them.” It sets out a geometric method for estimating the relative distances to the Sun and Moon, however, due to the primitiveness of the instruments that Aristarchus used, the results he obtained were far from actual. In this treatise, Aristarchus proceeds from the traditional idea of the geocentric structure of the world, however, Archimedes in his treatise “On the Calculation of Grains of Sand” and Plutarch in his treatise “On the Face on the Disk of the Moon” contain references to his heliocentric views.
The title is shocking. Understand. Everyone knows that “this is not so.” But let's figure out whether this is true or not.
Can we determine the size of the Moon based on the data that we can obtain from direct observations? It turns out that we can. And here's how.
During a solar eclipse, the Moon covers the Sun with its body - this is an eclipse. On the other hand, under the illumination of the Sun, the Moon casts a shadow on the surface of the Earth. Being in the zone of this shadow, the observer sees a total solar eclipse.
The direction of the sun's rays that illuminate the Moon during a solar eclipse is easy to determine. The angular dimensions of the Sun and the Moon are almost the same, which is what ensures a total eclipse of the Sun: the disk of the Moon exactly matches the disk of the Sun and covers it.
This means that the rays from the Sun hit the Moon, firstly, in a parallel flow and, secondly, exactly perpendicular to the cross section of the Moon.
From this, in turn, it follows that the shadow of the Moon is the same size as the Moon itself.
The shadow of the Moon on the surface of the Earth during a solar eclipse has long been measured - it has a diameter of approximately 270 kilometers.
This means that the size of the Moon should be the same - that is, 270 kilometers.
If I'm wrong, try to find the mistake in these "three pines". In the meantime, the skeptics are looking, I will remind you of the following.
Modern ideas about space as a space filled with stars and planets were formed quite recently - starting with Copernicus. Before him, the Earth was flat, and the stars were just sparkling lamps suspended on crystal spheres.
It is not at all necessary that Copernicus is right. There may be other versions of the space model. Here, for example, important question, which I asked readers interested in science about the strange trajectory of the Moon -
Rice. 1. Movement of the Moon relative to the Earth: smooth top - section of the upper (according to the picture) part of the trajectory; breaking points are the lower (according to the figure) inflection points of the trajectory.
In the earlier article “The Earth Doesn’t Revolve Around the Sun at All,” we looked at the situation related to the trajectory of the Moon. According to the generally accepted scientific version, the Moon should move along an epicycloid.
At inflection points, the Moon slows down to zero, and then picks it up again to its maximum value. We know from school: a change in speed is an acceleration. From the same school we also know: acceleration multiplied by mass gives birth to force.
So a logical conclusion arises: with such colossal forces that are formed at the inflection points of the epicycloid, not a single material can withstand such loads.
And this, in turn, means: either the Moon does not move in the way that is prescribed to it by generally accepted ideas of science, or the Moon has no mass.
It’s clear that you can’t understand such a situation at once, so we are moving forward gradually - from article to article. But I had to deal with the necessary elements of revising the old principles of physics when constructing the Unified Field Theory, the first provisions of which were formed in the monographs “” and “”.
Our projects in the field of physics: “Unified field theory // Theory of everything”; “Vacuum: (concept, structure, properties)”; "Periodic Table of Elementary Particles". And here: a review of the Institute of General Physics of the Russian Academy of Sciences and a description of the Computing Center of the Russian Academy of Sciences.
And here is our hypothesis: the formation of cosmic bodies using the example of Mars and Earth (based on modern ideas about vacuum). The corresponding report was made in 2013 at the Gordin Readings at the Institute of Earth Physics of the Russian Academy of Sciences.
Rice. 1. Dikusar V.V., Tyunyaev A.A. Vacuum: concept, structure, properties // Rep. editor corresponding member RAS Yu.A. Flerov. Federal State Budgetary Institution Computer Center named after. A.A. Dorodnitsyna Russian Academy Sci. 2013. Buy.
In my opinion, the problem of description real world is a time-varying problem that depends on our current knowledge of the world around us. If the day before yesterday the Earth lay calmly on three pillars, yesterday there was a choice between the concepts of Descartes and Newton, then today many questions have arisen about Newton’s “laws”.
And tomorrow a post-information society will be formed, in which completely new technologies will become a reality. Their meaning was clearly explained by Malysh and Carlson - when Carlson was trying to find his butt near the TV. We, who know how television works, laughed at the unlucky fairy-tale hero.
The Moon is the largest object at night starry sky. The ancient Greeks were able to calculate the approximate diameter of the Moon.
- the fifth largest natural satellite in the Solar System, second in size only to three satellites of Jupiter and one satellite of Saturn. The Moon is not much smaller than Mercury, the smallest of the planets, and half the size of Mars. In relation to the size of its planet, the Moon ranks first among satellites.
Dimensions
Due to rotation around its axis, it is slightly “flattened” at the poles, its diameter at the pole line is 3471.94 km, and at the equator line – 3476.28 km, which is about a quarter of the Earth’s diameter. Since our satellite has a spherical shape, other geometric dimensions can be calculated: the length of the Moon’s equator is 10920 km, the volume of our satellite is 1/50 of the Earth’s, and the surface area is 13 times less than the Earth’s.
Angular diameter
Since the lunar orbit is an ellipse, the angular diameter of the Moon varies from 33'40" at its closest point, the apogee, to 29'24" at its farthest point, the perigee. When low above the horizon, it appears larger than at the zenith, due to an optical illusion that has not yet been explained. The angular dimensions of the satellite almost coincide with the angular dimensions, which is why total solar eclipses are possible when the disk of the Moon completely covers the solar one.
How they measured it
The first to try to determine the diameter of the Moon was Aristarchus of Samos in the 3rd century BC. e. based on measurements taken during a solar eclipse and subsequent calculations based on Euclidean geometry. Due to measurement errors, the calculations turned out to be inaccurate. One hundred years later
MOON- natural satellite of the Earth. L. revolves around the Earth in an elliptical manner. orbit with an eccentricity of 0.05490 and a semimajor axis equal to av. distance from Earth - 384,400 km. Naib. the distance from the Earth at apogee is 405,500 km, the smallest at perigee is 363,300 km.
The barycenter of the Earth-Moon system is located at a distance of 4670 km from the Earth's center of mass. The plane of L.'s orbit is inclined to the plane of the ecliptic at an angle. Wed. the orbital speed of the aircraft is 1.023 km/s (3683 km/h). Daily speed of apparent movement of light among stars. The period of L.'s orbital motion is 27.32166 days (sidereal month) and is equal to the period of axial rotation. Thanks to this equality, the same hemisphere of the light is constantly facing the Earth. The phase change of the light occurs with a period of 29.53059 days (synodic month). The equator of L. has a post. inclination to the ecliptic plane. Unevenness of orbital motion at constant. speed of axial rotation of the plane leads to the phenomenon of libration in longitude with highest value. The inclination of the equatorial plane of the planet to the plane of its orbit causes librations in latitude from the maximum. meaning. Thanks to librations from the Earth, the surface of the moon is observed. Periodically, near the full moon phase, the moon appears partially or completely in the cone of the earth's shadow and lunar eclipses occur.
Geom. L.'s figure is close to a sphere, cf. the radius of the swarm is 1738.0 km. Angle radius of the visible disk of the Earth (at an average distance from the Earth). The surface area and volume of the light, respectively, and the mass of the light are equal, i.e. g. Avg. lunar rocks. Heterogeneities in the density of the lunar interior manifest themselves through anomalies in gravity. field L. With general non-centrality of gravitational the L. field has local anomalies that cause deformation of equipotential surfaces. Naib. large anomalies - mascons - have a local excess mass of approx. mass L.
Dark areas on the surface of the light are conventionally called. seas, light ones - continents. Total area marine formations on the surface of L. Basic the seas are concentrated within the visible hemisphere of the continent, which is consistent with the different thickness of the crust on the visible and reverse hemispheres. On the scale of the entire Latvia, the difference is avg. levels of continents and seas reaches 2.3 km; within the visible hemisphere this value is 1.4 km. The circular seas associated with the Mascones are located on average 1.3 km below sea level irregular shape and 4.0 km below avg. continental level. Basic The relief form is ring structures decomposed. sizes - impact craters. The general size distribution of the number of craters (per unit area) is described by a power law function. Tectonic traces processes are recorded in the form of linear structures in the main. such as faults, grooves and folds. The surface layer of the substance of L. - regolith - is a loose cover of crushed rocks, consisting of fragments of various sizes (sizes), including a fine dusty fraction. The average thickness of the regolith layer is 2-3 m.
Mineralogical the composition of lunar rocks is close to terrestrial rocks such as basalts, norites and anorthosites. The main rock-forming minerals, as on Earth, are pyroxene, plagioclase, ilmenite and olivine. While generally similar to terrestrial lunar rocks, they differ markedly in their content. oxides in basalts, in particular iron (more than ) and titanium (up to ). Some samples of basalt and norite rocks have a high content of potassium, rare earth elements and phosphorus (so-called creep rocks). The seas are composed of basalt-type rocks. The continents consist of rocks of the anorthosite series. Anorthosites differ from marine basalts and norites (non-marine basalts) by a higher content of aluminum oxides (up to ) and calcium (up to ). The content of iron and titanium oxides in these rocks is significantly lower. The density of light continental rocks of anorthositic composition is less than av. density
L. and is approx. 2.9 g/cm3. The density of marine basalts is 3.3 g/cm 3, i.e., it practically coincides with the average. density L. This means that light anorthositic rocks form a thin outer. shell - the lunar crust, and marine basalts have a direct connection with the deep substance of the subsoil.
The natural seismicity of the bowels of Latvia is relatively low. Isolation of complete seismic energy in the body of L. is less than erg per year, which is one time less than on Earth. Wed. the magnitude does not exceed 2 points on the Richter scale. Seismometers on the surface can record from 600 to 3000 moonquakes per year. According to active seismic experiments and studies of the nature of the propagation of body waves during deep-focus moonquakes, the bowels of Leningrad are divided into several. zones The very top. zone having a thickness (thickness) of approx. 60 km, and on the way back - approx. 100 km, identified with the lunar crust. The velocity of longitudinal waves in the second layer with a thickness of approx. 250 km lies in the range from 7.8 to 8.1 km/s. The main components of this layer are the top. mantle - may contain olivine and pyroxene. The third zone - Wed. mantle - has a thickness of approx. 500 km. It is characterized by a decrease in the speed of transverse waves to 3.6-4.0 km/s. The mare basalts appear to have resulted from partial rock formations in this zone. Lower region avg. The mantle at depths of 600-800 km includes sources of deep-focus moonquakes. The fourth zone is lower. mantle - characterized by the complete disappearance of transverse waves, which can be explained by the partially molten state of the rocks. Therefore, at a depth of approx. 800 km the solid shell ends - the lithosphere - and the lunar asthenosphere begins, the probable temperature is upper. parts of the cut are estimated at approx. 1200 K. At a depth of 1380-1570 km, the speed decreases sharply longitudinal waves, which marks the boundary of the fifth zone - the core. Assuming complete melting of the matter in this part of the lunar interior, calculations give a longitudinal wave velocity of approx. 5 km/s. As a preliminary hypothesis, a model of a core consisting of iron sulfide with a mass no more than the mass of the entire L is put forward.
Critical speed for L. 2.38 km/s, first space speed - 1.68 km/s. In most cases, the velocities of thermal motion of gas particles exceed these values, so gases either leave the cislunar space or are scattered over large distances from the surface of the planet. The gas shell - the atmosphere of the planet - is in a highly rarefied state and is physically properties are similar to conditions on earth. Basic the components are hydrogen, helium, neon and argon in a highly ionized state. Naib. the density of the gas shell is observed at night and, in terms of density at the surface, corresponds to the total concentration of gas ions of approx. . During the daytime, the concentration of gases drops to. This value is ~10 -13 concentration of gas molecules in the earth's atmosphere, but three to four orders of magnitude higher than the concentration of particles in solar wind at a distance of 1 a. e. from the Sun.
L. has virtually no global magnetism. field of a dipole nature and is non-magnetic, relatively non-conducting and cold dielectric. a sphere that absorbs solar wind plasma and streams of energetic particles freely falling onto its surface. Flowing around the planet, the solar wind forms a shadow, the extent of which varies depending on the relative orientation of the direction of the solar wind and the lines of force of the interplanetary magnetic field. fields. The magnitude of the global magnet. the field on the surface of the lens does not exceed 0.5 gamma. Local magnetic tension field explained in the main. paleomagnetism, can reach in dept. cases 100-300 gamma on the mainland,
from 43 to 103 gamma in transitional areas and from 40 to 3-6 gamma in marine areas.
According to estimates based on ground-based observations of meteorite matter in near-Earth space, the total flux falling on L. solids with masses from g (micrometeorites) to g (large meteorites and asteroids) is approx. Basic the mass consists of micrometeorites falling constantly at a speed of approx. 25 km/s. According to direct measurements on the surface of the light, the flux density of these particles is Presence of constant. The background of excess brightness in the UV and visible regions of the spectrum, detected from observations directly on the surface, indicates the existence of a rarefied dust cloud with a thickness of approx. km, with a particle size of 70 microns and a concentration of the order of , which is several times higher than the concentration of dust particles in interplanetary space.
The reflective surface of the coating substance has unique optical properties. properties. The reflection indicatrix of L. is strongly elongated towards the light source. The maximum brightness of a light's surface is achieved when the directions of the incident and reflected observed rays coincide. For observation conditions from Earth, this corresponds to the full moon phase. The visual magnitude of the moon during a true full moon is approx. . Geom. albedo 0.147, spherical albedo 0.075, Avg. reflectivity of the entire lunar surface, continental areas, marine areas. The surface layer of L. in its optical properties. properties are largely homogeneous. The reflected radiation flux is partially polarized. The maximum of lunar light occurs at phase angles and reaches a degree of polarization for the entire illuminated disk of approximately . The maximum of reflected light radiation occurs at a wavelength of approximately 0.6 microns, i.e., compared to sunlight has a somewhat reddish tint. The degree of redness varies depending on the type of surface. The maximum of intrinsic light falls in the region of 7 microns. The surface temperature at the subsolar point reaches 400 K. By the end of the lunar night, the surface cools down to 100 K.
The issues of education and early history of Latvia have not yet been finally resolved. There is no complete clarity as to where L. was formed as an independent celestial body. Certain chemical features. The composition of lunar rocks suggests that the moon and the Earth were formed in the same zone solar system, but were not a single whole in the past. The hypothesis of the separation of light from the Earth and the hypothesis of the capture of light by the Earth encounter many difficulties. At the earliest stage of the existence of L. (4.3-4.6 billion years ago), a global magmatic event occurred. differentiation, as a result of which the bark and top were formed. the mantle of Latvia under very intense meteorite bombardment. Most of the large continental craters and huge depressions - lunar basins - appeared during this era. The final stage of the formation of giant depressions, which later became seas on the visible hemisphere, coincided with the melting and crystallization of rocks of norite composition on the surface. The process of early lunar volcanism that gave rise to the basalt cover lunar seas, had two bursts of subsurface activity. The first ended with the melting of basalts from cf. 3.7 billion years old. The second is associated with the melting of basalts from the depths of the cf. 3.2 billion years old. The next two billion years are a time of complete gradual attenuation of lunar volcanism and solidification of the upper rocks. and Wed mantle to a depth of several hundred km. Meteor bombardment has become the main thing. factor in the formation of modern relief L.
Lit.: Ruskol E. L., Origin of the Moon, M., 1975; Galkin I.N., Geophysics of the Moon, M., 1978; Sagitov M.U., Lunar gravimetry, M., 1979; Shevchenko V.V., Modern selenography, M., 1980; him, The Moon and Its Observation, M., 1983. V. V. Shevchenko.
In addition to the scattering of stars, the decoration of the night sky is, of course, the Moon. The combination of its size and distance from Earth makes it the second brightest celestial object and can completely obscure the sun's disk during an eclipse. It is not surprising that the night star has attracted the attention of mankind for more than one millennium.
If the Earth did not have a Moon, many things would have turned out differently:
- the day would be much shorter;
- the seasons and climate would be characterized by instability;
- there would be less pronounced ebbs and flows;
- the appearance of life on the planet in its current form would be in question.
Moon diameter
The average diameter of the Moon is not too large by cosmic standards - 3474.1 km. This is approximately two times less than the distance from Moscow to Vladivostok.
Still, Luna ranks fifth place in size among the natural satellites of the planets of the Solar System:
- Ganymede.
- Titanium.
- Callisto.
- Moon.
But when comparing the sizes of satellites in relation to their planets, the Moon has no equal. With a diameter a quarter of the Earth's, it ranks first. In addition, its size is larger than that of Pluto.
What is the distance from the Earth to the Moon
The value is not constant. On average between the centers of the planet and its natural satellite 384,400 kilometers. This space would fit about 30 more Earths, and it takes light 1.28 seconds to travel that distance.
What if the nearest celestial body could be reached by car at a speed of 95 km/h? Considering that the entire distance is approximately 10 circles of the Earth, the journey would take the same amount of time as 10 trips around the planet along the equator. That is a little less than six months. So far, the fastest distance to the Moon has been covered by the interplanetary station New Horizons, which on its way to Pluto crossed the satellite’s orbit eight and a half hours after launch.
The Moon's orbit is not a perfect circle, but an oval (ellipse) within which the Earth is located. At different points it is located closer or further from the planet. Because of this, when rotating around a common center of mass with the Earth, the satellite either approaches or moves away. So, the fewest kilometers separate celestial bodies, when the night star is at a place in its orbit called perigee. At the point designated as apogee, the satellite is furthest from the planet. The minimum distance is 356,400 km, and the maximum is 406,700 km. So the distance fluctuates from 28 to 32 earth diameters.
The first close to correct estimates of the distance to the “neighbor” Earth were obtained back in the 2nd century. n. e. Ptolemy. Nowadays, thanks to modern reflective devices installed on the satellite, the distance has been measured most accurately (with an error of several cm). To do this, a laser beam is directed at the Moon. Then they note the period during which it will return to the Earth after being reflected. Knowing the speed of light and the time it took to reach the sensors, it is easy to calculate the distance.
How to visually estimate the size of the Moon and its distance to Earth
The Earth's diameter is approximately 4 times larger than the Moon's, and the volume is 64 times. The distance to the night star is approximately 30 times the diameter of the planet. To visually estimate the distance from the Earth to its satellite and compare their sizes, you will need two balls: a basketball and a tennis ball. Diameter ratios:
- Earth (12,742 km) and Moon (3,474.1 km) - 3.7: 1;
- standard basketball (24 cm) and tennis ball (6.7 cm) - 3.6:1.
The values are quite close. Thus, if the Earth were the size of a basketball, then its satellite would be the size of a tennis ball.
You can ask people to imagine that the Earth is a basketball, and the Moon is a tennis ball, and show how far the satellite is from the planet on this scale. Most will likely guess a distance of 30 cm to a few steps.
In fact, to show the correct distance, you will have to move away a little more than seven meters. Thus, there is an average of 384,400 km between the planet and its satellite, which is approximately 30 Earths or, respectively, 30 basketballs. Multiplying the diameter of the sports equipment by 30 gives the result 7.2 m. This is approximately 9 male or 11 female steps.
Apparent size of the Moon from Earth
360 angular degrees- the entire circumference of the celestial sphere. At the same time, the night star occupies about half of one degree on it (on average 31 minutes) - this is the angular (visible) diameter. For comparison: the width of the nail index finger at arm's length is approximately one degree, that is, two Moons.
By a unique coincidence, the apparent sizes of the Sun and Moon for the inhabitants of the Earth are almost the same. This is possible because the diameter of the nearest star 400 times the diameter of the satellite, but is also located daylight the same number of times further. Thanks to this coincidence, among all the planets revolving around the Sun, only Earth can observe its total eclipse.
Does the size of the moon change?
Of course, the true diameter of the satellite remains the same, but the apparent size may vary. So, The moon appears noticeably larger during sunrise and sunset. When the night star is low above the horizon, the distance to the observer does not decrease, but, on the contrary, increases slightly (by the radius of the Earth). The visual effect, it would seem, should be the opposite. There is no single answer explaining the cause of the illusion. We can only say with confidence that this beautiful phenomenon owes its existence only to the peculiarities of the functioning of the human brain, and not, for example, to the influence of the Earth’s atmosphere.
The distance between the Moon and the Earth periodically changes from maximum (at apogee) to minimum (at perigee). Along with the distance, the apparent diameter of the satellite also varies: from 29.43 to 33.5 arc minutes. Thanks to this, not only total eclipses are possible, but also annular (when the apparent size of the Moon at apogee is smaller than the solar disk). Approximately once every 414 days, the full moon coincides with the passage of perigee. At this time, you can observe the largest night star. The phenomenon has received the rather loud name of a supermoon, but the apparent diameter at this moment is only 14% larger than usual. The difference is very minor, and a casual observer will not notice the differences.
Thanks to precise measurements distances, scientists were able to detect a relatively slow but constant increase in the distance between the Earth and its satellite. The rate at which the Moon is receding - 3.8 cm per year - is too slow to notice a significant decrease in the apparent size of the star. Human nails grow at approximately the same rate. However, in 600 million years, the Moon will be so far away and, accordingly, smaller for observers on Earth that total solar eclipses will be a thing of the past.
It is worth noting that the earth's satellite, formed by modern theory from the collision of the planet with a large object 4.5 billion years ago, was initially 10−20 times closer. However, there was no one then to admire the sky, decorated with a star 10-20 times larger in diameter than now.
Video
You can understand how far the Moon is from the Earth by watching this video.