A detailed map of the location of lunar craters has been compiled. Sizes of the Moon How to measure the sizes of various formations on the moon

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What size is the moon- satellite of the Earth. Description of mass, density and gravity, real and apparent size, supermoon, illusion of the Moon and comparison with the Earth in the photo.

The Moon is the brightest object in the sky (after the Sun). To an earthly observer it seems gigantic, but this is only because it is located closer to other objects. In size it occupies 27% of the earth's (ratio 1:4). When compared with other satellites, ours is in 5th place in terms of size.

The average lunar radius is 1737.5 km. The value multiplied by two will be the diameter (3475 km). The equatorial circumference is 10917 km.

The area of ​​the Moon is 38 million km2 (this is less than any total area of ​​the continent).

Mass, density and gravity

• Weight – 7.35 x 10 22 kg (1.2% earthly). That is, the Earth exceeds the lunar mass by 81 times.
• Density – 3.34 g/cm 3 (60% earthly). According to this criterion, our satellite takes second place, losing to Saturn’s moon Io (3.53 g/cm3).
• The force of gravity increases only to 17% of the earth's, so 100 kg there will turn into 7.6 kg. This is why astronauts can jump so high on the lunar surface.

Supermoon

The Moon revolves around the Earth not in a circle, but in an ellipse, so sometimes it is located much closer. The closest distance is called perigee. When this moment coincides with a full moon, we get a supermoon (14% larger and 30% brighter than normal). It repeats every 414 days.

Horizon illusion

There is an optical effect that makes the apparent size of the Moon appear even larger. This happens when it rises behind distant objects on the horizon. This trick is called the moon illusion or the Ponzo illusion. And although it has been observed for many centuries, there is no exact explanation yet. In the photo you can compare the size of the Moon and the Earth, as well as the Sun and Jupiter.

One theory says that we are used to watching clouds at altitude and understand that on the horizon they are kilometers away from us. If the clouds on the horizon reach the same size as those overhead, then, despite the distance, we remember that they must be huge. But since the satellite appears at the same size as overhead, the brain automatically aims to zoom in.

Not everyone agrees with this formulation, so there is another hypothesis. The moon appears close to the horizon because we cannot compare its size with trees and other earthly objects. Without comparison, it seems larger.

To check for the moon illusion, you need to put your thumb on the satellite and compare the size. When it returns to height again, repeat this method again. It will be the same size as before. Now you know what size the Moon is.

Brief information The Moon is the Earth's natural satellite and the brightest object in the night sky. The gravity on the Moon is 6 times less than on Earth. The difference between day and night temperatures is 300°C. The Moon rotates around its axis at a constant angular velocity in the same direction in which it revolves around the Earth, and with the same period of 27.3 days. That is why we see only one hemisphere of the Moon, and the other, called the far side of the Moon, is always hidden from our eyes.


Moon phases. The numbers are the age of the Moon in days. Details on the Moon depending on equipment Thanks to its proximity, the Moon is a favorite object for astronomy enthusiasts, and deservedly so. Even the naked eye is enough to get a lot of pleasant impressions from contemplating our natural satellite. For example, the so-called “ash light” that you see when observing the thin crescent Moon is best visible in the early evening (at dusk) on a waxing Moon or early in the morning on a waning Moon. Also, without an optical instrument, you can make interesting observations of the general outlines of the Moon - seas and land, the ray system surrounding the Copernicus crater, etc. By pointing binoculars or a small low-power telescope at the Moon, you can study the lunar seas, largest craters and mountain ranges in more detail. Such an optical device, not too powerful at first glance, will allow you to get acquainted with all the most interesting sights of our neighbor. As the aperture increases, the number of visible details increases, which means there is additional interest in studying the Moon. Telescopes with an objective diameter of 200 - 300 mm allow you to examine fine details in the structure of large craters, see the structure of mountain ranges, examine many grooves and folds, and also see unique chains of small lunar craters. Table 1. capabilities of various telescopes

The Moon is a very bright object, which when observed through a telescope often simply blinds the observer. To reduce brightness and make viewing more comfortable, many amateur astronomers use a neutral gray filter or a variable density polarizing filter. The latter is more preferable, as it allows you to change the level of light transmission from 1 to 40% (Orion filter). How is this convenient? The fact is that the amount of light coming from the Moon depends on its phase and the magnification used. Therefore, when using a regular neutral density filter, you will now and then encounter a situation where the image of the Moon is either too bright or too dark. A filter with variable density does not have these disadvantages and allows you to set a comfortable brightness level if necessary.

Orion variable density filter. Demonstration of the possibility of selecting filter density depending on the phase of the moon

When is the best time to watch the Moon?
At first glance it seems absurd, but a full moon is not the best time to observe the Moon. The contrast of lunar features is minimal, making them almost impossible to observe. During the "lunar month" (the period from new moon to new moon) there are two most favorable periods for observing the Moon. The first begins shortly after the new moon and ends two days after the first quarter. This period is preferred by many observers, since the visibility of the Moon occurs in the evening hours.

The second favorable period begins two days before the last quarter and lasts almost until the new moon. These days, the shadows on the surface of our neighbor are especially long, which is clearly visible on the mountainous terrain. Another advantage of observing the Moon in the last quarter phase is that in the morning hours the atmosphere is calmer and cleaner. Thanks to this, the image is more stable and clear, which makes it possible to observe finer details on its surface.

Another important point is the height of the Moon above the horizon. The higher the Moon, the less dense the layer of air that the light coming from it overcomes. Therefore, there is less distortion and better image quality. However, the height of the Moon above the horizon varies from season to season.

When planning your observations, be sure to open your favorite planetarium program and determine the hours of best visibility.
The Moon moves around the Earth in an elliptical orbit. The average distance between the centers of the Earth and the Moon is 384,402 km, but the actual distance varies from 356,410 to 406,720 km, due to which the apparent size of the Moon ranges from 33" 30"" (at perigee) to 29" 22"" (apogee ).

Of course, you shouldn’t wait until the distance between the Moon and the Earth is minimal, just note that at perigee you can try to see those details of the lunar surface that are at the limit of visibility.

When starting your observations, point your telescope to any point near the line that divides the Moon into two parts - light and dark. This line is called the terminator, being the boundary of day and night. During the waxing Moon, the terminator indicates the place of sunrise, and during the waning Moon, the location of sunset.

Observing the Moon in the terminator area, you will be able to see the tops of the mountains, which are already illuminated by the sun's rays, while the lower part of the surface surrounding them is still in shadow. The landscape along the terminator line changes in real time, so if you spend a few hours at the telescope observing this or that lunar landmark, your patience will be rewarded with an absolutely stunning spectacle.

What to see on the Moon

Craters- the most common formations on the lunar surface. They get their name from the Greek word meaning “bowl.” Most lunar craters are of impact origin, i.e. formed as a result of the impact of a cosmic body on the surface of our satellite.

Lunar Seas- dark areas that stand out clearly on the lunar surface. At their core, seas are lowlands that occupy 40% of the total surface area visible from the Earth.

Look at the Moon at full moon. The dark spots that form the so-called “face on the Moon” are nothing more than the lunar maria.

Furrows- lunar valleys reaching hundreds of kilometers in length. Often the width of the furrows reaches 3.5 km, and the depth is 0.5–1 km.

Folded veins- resemble ropes in appearance and appear to be the result of deformation and compression caused by the subsidence of the seas.

Mountain ranges- lunar mountains, the height of which ranges from several hundred to several thousand meters.

Domes- one of the most mysterious formations, since their true nature is still unknown. At the moment, only a few dozen domes are known, which are small (usually 15 km in diameter) and low (several hundred meters) round and smooth elevations.

How to Observe the Moon
As mentioned above, observations of the Moon should be carried out along the terminator line. It is here that the contrast of lunar details is maximum, and thanks to the play of shadows, unique landscapes of the lunar surface are revealed.

When viewing the Moon, experiment with magnification and choose the one that is most appropriate for the given conditions and subject.
In most cases, three eyepieces will be enough for you:

1) An eyepiece that provides a slight magnification, or the so-called search eyepiece, which allows you to comfortably view the full disk of the Moon. This eyepiece can be used for general sightseeing, for observing lunar eclipses, and can also be used to conduct lunar excursions for family members and friends.

2) An eyepiece of medium power (about 80-150x, depending on the telescope) is used for most observations. It will also be useful in unstable atmospheres where high magnification is not possible.

3) A powerful eyepiece (2D-3D, where D is the lens diameter in mm) is used for a detailed study of the lunar surface at the limit of the telescope’s capabilities. Requires good atmospheric conditions and complete thermal stabilization of the telescope.

Your observations will be more productive if they are focused. For example, you can start studying with the list of "" compiled by Charles Wood. Also pay attention to the series of articles “”, telling about lunar attractions.

Another fun activity can be finding tiny craters that are visible at the limits of your equipment.

Make it a rule to keep an observation diary, where you regularly record observation conditions, time, moon phase, atmospheric conditions, magnification used and a description of the objects you saw. Such records can also be accompanied by sketches.

10 most interesting lunar objects

(Sinus Iridum) T (moon age in days) - 9, 23, 24, 25
Located in the northwestern part of the Moon. Available for observation with 10x binoculars. Through a telescope at medium magnification it is an unforgettable sight. This ancient crater, 260 km in diameter, has no rim. Numerous small craters dot the surprisingly flat bottom of Rainbow Bay.










(Copernicus) T – 9, 21, 22
One of the most famous lunar formations can be observed with a small telescope. The complex includes a so-called ray system extending 800 km from the crater. The crater is 93 km in diameter and 3.75 km deep, making for spectacular views of the sun rising and setting over the crater.









(Rupes Recta) T - 8, 21, 22
A tectonic fault 120 km long, easily visible with a 60 mm telescope. A straight wall runs along the bottom of a destroyed ancient crater, traces of which can be found on the eastern side of the fault.











(Rümker Hills) T - 12, 26, 27, 28
A large volcanic dome, visible with a 60 mm telescope or large astronomical binoculars. The hill has a diameter of 70 km and a maximum height of 1.1 km.











(Apennines) T - 7, 21, 22
Mountain range with a length of 604 km. It is easily visible through binoculars, but its detailed study requires a telescope. Some peaks of the ridge rise 5 or more kilometers above the surrounding surface. In some places the mountain range is crossed by furrows.










(Plato) T - 8, 21, 22
Visible even with binoculars, Plato Crater is a favorite site among astronomy enthusiasts. Its diameter is 104 km. Polish astronomer Jan Hevelius (1611 -1687) named this crater “Great Black Lake”. Indeed, through binoculars or a small telescope, Plato looks like a large dark spot on the bright surface of the Moon.









Messier and Messier A (Messier and Messier A) T - 4, 15, 16, 17
Two small craters, which require a telescope with a 100 mm lens diameter to observe. Messier has an oblong shape measuring 9 by 11 km. Messier A is a little larger - 11 by 13 km. To the west of the craters Messier and Messier A there are two bright rays 60 km long.










(Petavius) T - 2, 15, 16, 17
Although the crater is visible through small binoculars, the truly breathtaking picture is revealed through a telescope with higher magnification. The dome-shaped floor of the crater is dotted with grooves and cracks.











(Tycho) T - 9, 21, 22
One of the most famous lunar formations, famous mainly for the gigantic system of rays surrounding the crater and stretching for 1450 km. The rays are perfectly visible through small binoculars.











(Gassendi) T - 10, 23, 24, 25
The oval crater, stretching for 110 km, is accessible for observation with 10x binoculars. Through a telescope it is clearly visible that the bottom of the crater is dotted with numerous crevices, hills, and there are also several central hills. An attentive observer will notice that in some places the walls of the crater are destroyed. At the northern end is the small crater Gassendi A, which, together with its older brother, resembles a diamond ring.

11 WORK 2 PHYSICAL NATURE OF THE MOON Purpose of the work: Studying the topography of the Moon and determining the size of lunar objects. Benefits: Photograph of the lunar surface, schematic maps of the visible reverse hemispheres of the Moon, lists of lunar objects (Tables 3 and 4 in the Appendix). The Moon is a natural satellite of the Earth. Its surface is covered with mountains, cirques and craters, long mountain ranges. It has wide depressions and is cut by deep cracks. Dark spots on the surface of the Moon (lowlands) were called “seas.” Most of the surface of the Moon is occupied by “continents” - lighter hills. The lunar hemisphere visible from earth has been very well studied. The far hemisphere of the Moon is not fundamentally different from the visible one, but there are fewer “marine” depressions on it and small, light, flat areas called galassoids have been discovered. About 200,000 features have been recorded on the lunar surface, of which 4,800 have been cataloged. The relief of the Moon was formed in a complex process of evolution with the participation of internal and external forces. The study of the lunar surface is carried out using photographs and maps compiled on their basis. It should be remembered that photographs and maps reproduce a telescopic image of the Moon, in which its north pole is located below. Determination of the linear dimensions of lunar formations. Let d1 be the linear diameter of the Moon, expressed in kilometers; d2 is the angular diameter of the Moon, expressed in minutes; D is the linear diameter of the photographic image of the Moon in millimeters. Then the scales of the photograph will be: linear scale: l = d1/D, (1) angular scale: ρ = d2/D. (2) The apparent angular diameter of the Moon varies depending on its parallax, and its values ​​for each day of the year are given in astronomical yearbooks. However, approximately d2 = 32’ can be taken. Knowing the distance to the Moon (r = 380000 km) and its angular diameter, we can calculate the linear diameter d1 = r ⋅ d2. By measuring the size d of a lunar object in a photograph with known scales in millimeters, we obtain its angular dρ and linear d1 12 dimensions: dρ = ρ ⋅ d, (3) d1 = l ⋅ d. (4) Using the known scales l and ρ of a photograph of the full Moon, one can determine the scales l1 and ρ1 of a photograph of a section of the lunar surface. To do this, it is necessary to identify identical objects and measure the dimensions d and d’ of their images in photographs in millimeters. On the scale of a photograph of a section of the lunar surface: dρ = ρ1 ⋅ d’, (5) d1 = l1 ⋅ d. (6) Using formulas (3) and (4), we have: l1 = l ⋅ d/d’, (7) ρ1 = ρ ⋅ d/d’. (8) Using the obtained scales ρ1 and l1, it is possible to determine the angular and linear dimensions of lunar objects with sufficient accuracy. Work progress. 1. Determine the names of lunar objects listed under the numbers indicated by the teacher. 2. Calculate the angular and linear scales of the photographic map of the visible hemisphere of the Moon and determine the angular and linear dimensions of the sea, the length of the mountain range and the diameters of two craters (as instructed by the teacher). 3. Using a photograph of a section of the lunar surface, identify objects on the lunar surface, based on their sizes, calculate the scale of this photograph. Submit a work report using a self-developed form. Test questions. 1. What observations of the Moon prove that there is a change of day and night there? 2. How many revolutions around its axis does the Moon make relative to the Sun during the year? 3. Is it possible to observe lunar auroras while on the Moon? 4. Why does the Moon face the Earth with one side, but is observed in different phases? 5. Why can more than 50% of the Moon’s surface be observed from Earth? 13 WORK 3 STAR SYSTEMS Purpose of the work: To become familiar with some methods for studying galaxies. Benefits: Photographic standards of various types of galaxies, photographs of galaxies. One of the simplest and therefore most used of the currently existing classifications of galaxies is the Hubble classification. Galaxies in this classification are divided into irregular (I), elliptical (E) and spiral (S). Each class of galaxies contains several subclasses or types. By comparing photographs of the galaxies being studied with photographs of their characteristic representatives, according to which the classification was created, the types of these galaxies are determined. If the distance D to the galaxy or the distance module (m−M) is known, where m is the visible and M is the absolute magnitude of the object, then from the measured angular dimensions p one can calculate its linear dimensions: l = D ⋅ Sin(p). (1) Since the apparent sizes of galaxies are very small, then, expressing p in minutes of arc and taking into account that 1 radian = 3438’, we obtain: l = D ⋅ p/3438’. (2) The absolute magnitude of the object is M = m + 5 – 5logD. (3) However, the distance D calculated modulo the distance will be overestimated if the absorption of light in space is not taken into account. To do this, in formula (3) it is necessary to take into account the corrected value of the apparent magnitude: m' = m - γCE, (4) where γ is the coefficient, which for visual rays (using mv) is equal to 3.7, and for photographic rays (using mpg ) is equal to 4. 7. CE = C – C0. (5) C = mpg – mv is the visible color index, and C0 is the true color index, determined by the spectral class of the object (Table 2 in the Appendix). 14 Then, logD = 0.2(m' – M) + 1. (6) The distance to the galaxy can be determined by the red shift of the lines in its spectrum: D = V/H, (7) where H = 100 km/s Mpc is the Hubble constant ; V = с ⋅ ∆λ/λ; c = 300,000 km/sec – speed of light; ∆λ = λ’ - λ; λ’ - wavelength of shifted lines; λ is the normal wavelength of the same lines. Work progress. 1. Determine the names of the constellations in which the star systems are located. 2. Using the scale of the photograph of the star system indicated by the teacher, determine its angular dimensions. 3. Using the angular dimensions and modulus of the distance, calculate the linear dimensions and distance to the same star system. 4. According to the Hubble classification, classify the star systems indicated in Table 11*. 5. Present the results of measurements and calculations in the form of tables and draw conclusions. Test questions. 1. Hubble's law. 2. What is redshift? 3. Main characteristics of galaxies. 4. What is our Galaxy? 15 Table 11. No. Number of stars. Equatorial Visible stars. Spectrum Coordinate system module value Sp dist. NGC M α δ mv mpg mv-Mpg h m m 1 4486 87 12 28 .3 +12°40' 9 .2 10m.7 G5 +33m.2 2 5055 63 13h13m.5 +42°17' 9m.5 10m.5 F8 +30m.0 3 5005 − 13h08m.5 +37°19' 9m.8 11m.3 G0 +32m.9 4 4826 64 12h54m.3 +21°47' 8m.0 8m.9 G7 +26m.9 5 3031 81 9h51m,5 +69°18' 7m,9 8m,9 G3 +28m,2 6 5194 51 13h27m,8 +47°27' 8m,1 8m,9 F8 +28m,4 7 5236 83 13h34m,3 - 29°37' 7m.6 8m.0 F0 +28m.2 8 4565 − 12h33m.9 +26°16' 10m.2 10m.7 G0 +30m.3 * NGC – “New General Catalog of Nebulae and Star Clusters”, compiled by Dreyer and published in 1888; M – “Catalogue of Nebulae and Star Clusters”, compiled by Messier and published in 1771. LITERATURE 1. Vorontsov-Velyaminov B.A. Astronomy: for 11th grade of high school. – M.: Education, 1989. 2. Bakulin P.I., Kononov E.V., Moroz V.I. General astronomy course. – M.: Nauka, 1983. 3. Mikhailov A.A. Atlas of the starry sky. – M.: Nauka, 1979. 4. Galkin I.N., Shvarev V.V. Structure of the Moon. – M.: Znanie, 1977. 5. Vorontsov-Velyaminov B.A. Extragalactic astronomy. – M.: Nauka, 1978. Compiled by: Raskhozhev Vladimir Nilovich Leonova Liana Yuryevna Editor Kuznetsova Z.E. 16 APPENDIX Table 1. Information about bright stars Name in Spectrum. Temperature Distance Visible star Name Color of star constellation class 103 K St. g. ps magnitude Aldebaran α Taurus K5 3.5 Orange 64 20 1m.06 Altair α Eagle A6 8.4 Yellowish 16 4.9 0m.89 Antares αScorpio M1 5.1 Red 270 83 1m.22 Arcturus α Bootes K0 4.1 Orange 37 11.4 0m.2 4 Betelgeuse α Orionis M0 3.1 Red 640 200 0m,92 Vega α Lyrae A1 10.6 White 27 8.3 0m,14 Deneb α Cygnus A2 9.8 White 800 250 1m,33 Capella α Auriga G0 5.2 Yellow 52 16 0m,21 Castor α Gemini A1 10.4 White 47 14.5 1m .58 Pollux β Gemini 4.2 Orange 33 10.7 1m.21 Procyon α Canis Minor F4 6.9 Yellowish 11.2 3.4 0m.48 Regulus α Leo B8 13.2 White 80 24 1m.34 Rigel β Orionis B8 12.8 Blue 540 170 0m.34 Siri mustache α Canis Majoris A2 16.8 White 8.7 2.7 -1m.58 Spica α Virgo B2 16.8 Blue 300 90 1m.25 Fomalhaut α Southern Pisces A3 9.8 White 23 7.1 1m.29 Table 2. True color index Spectrum. O5 B0 B5 A0 A5 F0 F5 G0 G5 K0 K5 M0 M5 class True indicator -0m.50 -0m.45 -0m.39 -0m.15 0m.00 +0m.12 +0m.26 +0m.42 +0m, 64 +0m,89 +1m,20 +1m,30 +1m,80 colors, C0 17 Table 3. List of names of lunar seas Russian name International name Ocean of Storms Oceanus Procellarum Central Bay Sinus Medium Bay of Heat (Unrest) Sinus Aestuum Sea of ​​Fertility ( Abundance) Mare Foecunditatis Sea of ​​Nectar Mare Nectaris Sea of ​​Tranquility Mare Tranquillitatis Sea of ​​Crises (Dangers) Mare Crisium Sea of ​​Clarity Mare Serenitatis Sea of ​​Cold Mare Frigoris Bay of Dew Sinus Roris Sea of ​​Rain Mare Imbrium Bay of the Rainbow Sinus Iridum Sea of ​​Vapor Mare Vaporum Sea of ​​Clouds Mare Nubium Sea of ​​Humidity Mare Humorum Smith Sea Mare Smythii Marginal Sea Mare Margins Southern Sea Mare Australe Moscow Sea Mare Mosquae Dream Sea Mare Ingenii Eastern Sea Mare Orientalis Table 4. Ordinal list of lunar cirques and craters. Russian International No. Russian International No. transcription transcription transcription transcription 1 Newton Newton 100 Langren Langrenus 13 Claudius Clavius ​​109 Albategnius Albategnius 14 Scheiner Scheiner 110 Alphonsus Alphonsus 18 Nearchus Nearchus 111 Ptolemy Ptolemaeus 22 Maginus 119 Hipparchus 29 Wilhelm Wilhelm 141 Hevelius Hevelius 30 Tycho Tycho 142 Riccioli Riccioli 32 Stoefler 146 Kepler Kepler 33 Maurolycus 147 Copernicus Copernicus 48 Walter Walter 168 Eratosthenes Eratosthenes 52 Furnerius Furnerius 175 Herodotus Herodotes 53 Stevin Stevinus 176 Aristarchus Aristarchus 69 Vieta 186 Posidonius Posidonius 73 Purbach Purbach 189 Autolycus Autolycus 74 Lacaille La-Caile 190 Aristillus Aristillus 77 Sacrobosco Sacrabosco 191 Archimedes Archimedes 78 Fracastor Fracastor 192 Timocharis Timocharis 80 Petavius ​​Petavius ​​193 Lambert Lambert 84 Arzachel Arzachel 201 Gauss Gauss 86 Bullialdus Bullialdus 208 Eudoxus 88 Cavendish Cavendish 2 09 Aristotle Aristoteles 89 Mersenius Mersenius 210 Plato Plato 90 Gassendi Gassendi 220 Pythagoras Pythagoras 95 Catharina Catharina 228 Atlas Atlas 96 Cyril Cyrillus 229 Hercules Hercules

The moon, when we see it high above the horizon, seems very small to us: its apparent dimensions are usually compared to objects 25-30 cm in diameter. When we see the Moon close to the horizon, its size appears much larger. It is often thought that in this case the Moon is closer to us, but this is completely wrong: measurements have established that the Moon has the same apparent dimensions both at the horizon and high above the sky.

When the Moon is low above the horizon, we involuntarily exaggerate its apparent size by comparing the Moon's disk with objects that are visible in the same direction where the Moon is (houses, trees, etc.). Due to their remoteness, these objects also have very small apparent sizes; We unconsciously compare the apparent dimensions of the Moon with the true dimensions of earthly objects.

Determining the apparent size of the Moon in the sky by comparison with objects on earth is done differently by different people. But here is more accurate objective data on this matter: we can approximately compare the visible dimensions of the Moon with the visible dimensions of a bronze penny placed at a distance of one meter from us.

This seems completely incredible. But it is not difficult for anyone to see that this is so. Try to measure the apparent diameter of the Moon yourself using a small strip of paper.

Let's try to make a small cutout on the edge of this strip that would fit the entire visible diameter of the Moon, from edge to edge. Having done this, let's measure the cutout: its size will be approximately equal to the diameter of the bronze penny.

You can imagine the apparent size of the Moon in the sky by doing another experiment. Take a mirror on a moonlit night, stand with your back to the Moon and see how big the Moon is reflected in it. You will see a small bright spot, approximately half a centimeter in size. But, of course, the true size of the Moon is very far from its apparent size: the Moon is very far from us and therefore only seems small.

Knowing the actual distance to the Moon and having the ability to accurately measure its apparent diameter (diameter), one can calculate its true diameter. It turns out that the actual diameter of the Moon (the greatest distance from the edge to the edge) is 3476 km. This is approximately equal to the distance from Moscow to Tomsk.

As you know, the equatorial diameter of the globe is 12,757 km. This means that the diameter of the Moon is four times smaller than the Earth. More precisely, the diameter of the Moon is 0.272 times the diameter of the Earth (7).

But the Moon is a ball, like the Earth. It is calculated that the circumference of this ball is 10,920 km; it is therefore approximately four times smaller than the equatorial circumference of the Earth, equal to 40,077 km. And the surface of the Moon is 37,965,499 square meters. km, that is, it is less than the surface of the globe, which is 510,000,000 square meters. km, almost 14 times.

The surface of the Moon can be compared in area to the space occupied on Earth by North and South America together. Our vast homeland occupies an area exceeding half of the entire surface of the Moon.

Using the now well-known geometry formula for determining the volume of a sphere, it is easy to calculate the volume of the Moon in cubic kilometers. This is how this volume is expressed: 2,210,200,000 cubic meters. km.

Meanwhile, the volume of the globe is determined by the number 1083,000,000,000 cubic meters. km. Consequently, the Moon is 50 times smaller in volume than the Earth; more precisely: the volume of the Moon is 0.0202 that of the Earth.

It is very remarkable, however, that the Moon has a relatively even smaller mass than the Earth.

Let us remind readers that the mass of any body is characterized by the amount of substance contained in it for a given volume. The more substance there is in a given body, the more it weighs; therefore, the more effort must be applied to, say, lift or move a given body.

Careful observations of the movement of the Moon and accurate calculations allow us to conclude that the Moon is almost 82 times lighter than the Earth. And in terms of volume, as we already know, the Moon is approximately fifty times smaller than the Earth. This means that the Moon also has a lower density than the Earth (only 0.6 the density of the Earth). However, we will talk about the density of the Moon later.

These are the main figures characterizing the size of the Moon. We see that the Moon is far from being as small as we previously thought about it, as it was depicted in fairy tales and religious legends, and as it appears to the eye.