Today, any student who has not skipped geography lessons will be able to answer the question posed in the title of the article. The length of the equator is just over forty thousand kilometers. But far from always people possessed this information, so first we will plunge into history.

The earth stands on three pillars...

Even at the very dawn of human civilization, in the Neolithic era, people began to think about the structure of the world around them, the structure of the Earth. In many ways, their ideas were based on mythology, with the help of which attempts were made to explain the phenomena of nature and the movement of heavenly bodies. In the absence of written sources modern historians they cannot say with accuracy what Neolithic people thought about the structure of the Earth. However, later, after the invention of signs that allow the preservation of ancient wisdom, it became possible to create entire scientific treatises. And in one of the ancient Indian texts, the theory was reflected, according to which the flat Earth rests on three giant whales, and the whales swim in the ocean. What the ocean rests on is not reported in the treatise. But what can we say about ancient people, if even today in the USA, as if confirming the words of Mikhail Zadornov, there is a “Society flat earth”, whose members defend their point of view, and explain the entire space program as a global conspiracy!

From geocentric...

However, with the development of science, three whales ceased to satisfy scientists, and in ancient Greece a theory appeared according to which the Earth, which has the shape of a ball, is at the center of the universe, and the Sun, Moon and stars revolve around it. The outstanding astronomer of antiquity, Ptolemy, also adhered to this point of view.

... to the heliocentric theory of the structure of the solar system

Although this theory was a big step forward, it could not explain all the visible changes in the starry sky, so the heliocentric theory was developed in parallel with the geocentric one, but many more years passed until the Polish astronomer Nicolaus Copernicus was able to prove its validity.

Equator

The adoption of the heliocentric theory made it possible to define such a concept as the "equator". This is an imaginary line that runs along the surface of the Earth in a plane passing through its center and perpendicular to the axis of rotation of the planet. But if we figured out the definition, then the debate has not subsided so far about how long the equator is. To measure this value, without modern instruments, people had to at least reach this line.

The first sailors

For the first time, navigation arose in the Mediterranean Sea and was a coastal navigation, that is, along the coast, without losing sight of it. However, the Phoenicians soon learned to determine the position of their ship by the stars and were able to break away from the coast. After passing through the Pillars of Hercules (Strait of Gibraltar), they entered the Atlantic Ocean, crossed the equator and circled Africa. One of the proofs of such voyages is the famous White Lady of Brandberg, a cave drawing in Namibia. However, reaching the border between the Northern and southern hemispheres still did not allow to determine what the length of the equator is.

Age of Discovery

Soon people became so friendly with the sea-ocean that they began to swim farther and farther away from their native shores. Loud discoveries of new lands and sea routes followed: America, the waterway to India, Australia. And finally, Magellan's first circumnavigation of the world. This Portuguese navigator was the first to decide to find out what the length of the equator really is. And he led the expedition, which set itself the task of circumnavigating the globe. But it's all a joke. Ferdinand Magellan really made a trip around the world, but not strictly along the equator, but as the geography of the oceans allowed.

From travelers to scientists

Since it is rather difficult to determine such a value as the length of the equator by direct measurement "on the ground", some scientists decided to find the desired number using mathematical calculations. The ancient Greek mathematician Eratosthenes was the first to undertake such work. At the invitation of the Egyptian king Ptolemy III, he moved to Alexandria, where he soon became the keeper of her library. After a series of complex experiments and calculations, he determined that the length of the Earth's equator is 252,000 stadia. Since Eratosthenes lived and worked in Alexandria, he used Egyptian stages. If we translate them into kilometers familiar to us, then the length of the equator will be 39,690 kilometers, which is quite close to the true value. The error is less than 1 percent, for those times simply amazing accuracy of calculations.

The length of the Earth at the equator through the eyes of modern scientists

Years passed, centuries. Improved measuring instruments and techniques. Mankind went into space and was able to create detailed maps earth's surface. Accordingly, the length of the equator was determined more accurately. The line of zero latitude runs along the earth's surface, which has a height difference relative to the level of the world ocean from 10,994 meters (Challenger Abyss, Mariana Trench), up to 8,848 meters (Mount Chomolungma). And although such sharp changes in heights are not observed directly at the equator, it still makes it very difficult to measure its length. Therefore, for calculations, the average Earth radius, which, according to the WGS-84 geophysical standard, is 6378 kilometers 137 meters, which gives an equator length of 40,075 km.

Is the length of the equator a constant value?

And now let's try to answer the question of what is the reason for the discrepancy in the values ​​of the length of the equator between modern scientists and Eratosthenes. Perhaps the whole point is not only in the imperfection of measuring instruments? What if the equator just got longer? Modern scientists adhere to the theory of the structure of the Earth and the drift of continents based on plate tectonics. However, back in 1968, the Soviet geologist Vladimir Larin put forward the theory of the hydride structure of the Earth's core. He suggested that the substance from which our planet was formed contained a large amount of atomic hydrogen. It reacted with iron and nickel, which make up the Earth's core, resulting in the formation of hydrides of these elements. As a result of internal processes in the bowels of the planet, the core gradually warms up and hydrogen is released. This leads to a decrease in density and, accordingly, to an increase in the size of the Earth. This theory not only more fully explains the "drift" of the continents, but also makes it possible to explain the formation of mineral deposits, primarily hydrocarbons. So it is quite possible that oil, gas, coal are of abiogenic origin, and their synthesis in the bowels of the planet is still taking place. Moreover, confirmation of the work of the Soviet scientist was also found in ancient Zoroastrian myths, where it is said that in order to increase the surface of the Earth, the gods increased its size three times by one third. This theory, among other things, makes it possible to explain the mass extinction in a short period of time of many species of ancient animals, the so-called Triassic massacre. The most interesting thing is that the increase in the radius of the planet occurs at the present time, by about two centimeters per year. This is confirmed by regular measurements of scientists, but earlier these results could not be explained, except for the absorption of dust from outer space by the Earth. So over time, the length of the equator will increase.

Where does the equator pass and what is it, what is its duration and why did scientists even need to invent this imaginary line. Let's talk about all this in more detail.

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Concept definition

The equator is a conditional line that runs exactly through the center of our planet. Geographic latitude of the equator- 0 degrees. It serves as a reference point and enables scientists to carry out various calculations, which will be discussed below. The equator divides the globe into two absolutely equal parts.

Important! In the territories along which the equator passes, the night is always equal to the day, without deviation even for a fraction of a second.

The equatorial zone receives the most ultraviolet rays. Therefore, the farther the point is from the conditional line, the less heat and light it receives. That is why the highest temperature indicators were registered in the region of the conditional line.

Purpose

To conduct various calculations, scientists need to designate the special separators of the planet, which are the equator, parallels and meridians.

These conditional lines allow you to determine the position of various objects, enable aircraft to navigate in, and ships - to.

In addition, it is this band that allows scientists to divide the entire territory of the planet into climatic zones or belts.

In fact, the circumference of the equator is a key metric characteristic that is taken into account. It helps not only in such sciences as geodesy or elementary geography, but also in astrology and astronomy.

At the equator at this moment the territories of fourteen states are located. political map The world is constantly changing: countries appear and disappear, their borders can expand or narrow. What states are we talking about?

• Brazil,
• Ecuador,
• Indonesia,
• Maldives and other countries.

What is the circumference of the earth at the equator

According to the most accurate calculations, the length of the equator per kilometer is 40075 km. But the length of the Earth's equator in miles reaches 24901 miles.

As for such a thing as radius, it can be polar and equatorial. The dimensions of the first in kilometers reach 6356, and the second - 6378 km

All areas in close proximity to this imaginary line have a warm and humid climate.

It is no coincidence that life in these areas is simply seething. This is where most of the variety of plant and animal species.

Equatorial forests are considered the densest in the world, and some of them are completely impenetrable wilds, even taking into account all modern scientific achievements.

Precipitation in the equatorial zone is almost daily and very plentiful. That is why everything that is and grows here shines with a wide variety of colors.

On the planet there is a volcano named Wolf. So, the fact is that it is currently active and, interestingly, is located on both sides of the conditional line.

Attention! The average annual temperature in this area reaches 25-30 degrees Celsius.

Heat all year round makes the countries that are in this region an ideal holiday destination for tourists. This is especially true of the popular resorts located in the Maldives, where millions of tourists from all over the world come every year.

Important! There is a glacier at the equator. It is located at an altitude of 4690 meters on the slope of a volcano called Cayambe.

it amazing place, especially for . The fact is that the speed of rotation of the Earth on this conditional line reaches more than 460 meters per second.

The speed of sound at the same time reaches only 330 meters per second. Therefore, any spacecraft, which are launched from here, already, as it were, start at supersonic speed.

We talked about how long the equator is, what role it plays in modern life person. As many as three countries are named in his part.

We all live on the beautiful planet Earth, about which humanity has already learned a lot, but even more is still hidden from us and is waiting in the wings until a person’s desire for knowledge reveals all the secrets of our world.

General information about the planet Earth

Let's remember what we know about planet Earth. Earth is the only inhabited planet in our solar system, even more so, the only one on which there is life. The Earth is the third planet in a row, if you count from the Sun, before the Earth there are two more planets Mercury and Venus. The Earth rotates around the Sun and the tilt of the axis of rotation relative to the Sun is 23.439281 °, thanks to this tilt we can observe the change of seasons throughout the year. The distance from the earth to the sun is 149,600,000 km, in order for a stream of light to overcome the distance from the Sun to the Earth, it needs 500 seconds or 8 minutes. Our planet also has a satellite, the Moon, which revolves around the Earth, just as the Earth revolves around the sun. The distance from the Earth to the Moon is 384400 km. The speed of the Earth in its orbit is 29.76 km/sec. earth does full turn around its axis in 23 hours 56 minutes and 4.09 seconds. For convenience, it is considered that there are 24 hours in a day, but in order to compensate for the remaining time in the calendar, one more day is added every 4 years and this year is called a leap year. A day is added in the month of February, which usually has 28 days, in a leap year 29 days. There are 365 days in a year and 366 days in a leap year, this is a full cycle of seasons (winter, spring, summer, autumn).

Earth dimensions and parameters

Now let's fast forward from space to the planet Earth itself. In order for life to arise on the planet, there must be many factors and conditions that create favorable environment habitat for countless living organisms inhabiting the Earth. In fact, the more we learn about our common home, the more clearly we understand how complex and perfect the planet Earth is. There is nothing superfluous, everything has its place, and everyone has an important role to play.

The structure of the planet Earth

There are 8 planets in our solar system, 4 of which are planets terrestrial group and 4 to the gas group. Planet Earth is the largest terrestrial planet and has the largest mass, density, magnetic field and gravity. The structure of the Earth is not homogeneous, and conditionally it can be divided into layers (levels): the earth's crust; mantle; nucleus.
Earth's crust - the uppermost layer of the solid shell of the Earth, it, in turn, is divided into three layers: 1) sedimentary layer; 2) granite layer; 3) basalt layer.
The thickness of the earth's crust can be in the range of 5 - 75 km deep into the Earth. Such a run-up depends on the places of measurements, for example, at the bottom of the ocean, the thickness is minimal, and on the continents, on mountain ranges, the maximum. As we have already said, the earth's crust is divided into three parts, the basalt layer was formed first, therefore it is the lowest, followed by the granite layer, which is absent from the ocean floor, and the uppermost sedimentary layer. The sedimentary layer is constantly formed and modified, and man plays an important role in this.
Mantle - the layer following the earth's crust, which is the most voluminous, about 83% of the total volume of the Earth and approximately 67% of its mass, the mantle thickness reaches 2900 km. The upper layer of the mantle, which is 900 km, is called magma. Magma is molten minerals, also the output of liquid magma is called lava.
Nucleus - this is the center of the planet Earth, it consists mainly of iron and nickel. The radius of the earth's core is about 3500 km. The core is also divided into an outer core with a thickness of 2200 km, it has a liquid structure and an inner core with a radius of about 1300 km. The temperature in the center of the nucleus is close to 10,000 °C; on the surface of the nucleus, the temperature is well below 6,000 °C.

Earth shape. Earth diameter. The mass of the earth. Age of the Earth.

If we ask the question, “What is the shape of the Earth?”, We will hear the answer options: round, ball, ellipsoid, but this is not entirely true, a special term Geoid was introduced to denote the shape of the Earth. The geoid is essentially an ellipsoid of revolution. Determining the shape of the planet made it possible to accurately determine the diameters of the planet Earth. Yes, it is the diameters of the Earth due to the irregular shape that they are distinguished by several:
1) the average diameter of the Earth is 12,742 km;
2) the equatorial diameter of the Earth is 12756.2 km;
3) the polar diameter of the Earth is 12713.6 km.

The circumference along the equator is 40,075.017 km, and along the meridian is slightly less than 40,007.86 km.
The mass of the earth is quite relative value, which is constantly changing. The mass of the earth is 5.97219 × 10 24 kg. The mass increases due to the settling of cosmic dust on the surface of the planet, the fall of meteorites, etc., due to which the mass of the Earth annually increases by about 40,000 tons. But due to the dispersion of gases into outer space, the mass of the Earth is reduced by about 100,000 tons per year. Also, the loss of mass of the Earth is affected by an increase in temperature on the planet, which contributes to more intense thermal movement and leakage of gases into space. The smaller the mass of the Earth becomes, the less its attraction and the more difficult it becomes to keep the atmosphere around the planet.
Thanks to the method of radioisotope dating, scientists managed to establish the age of the Earth, it is 4.54 billion years. The age of the Earth was more or less accurately determined back in 1956, subsequently, with the development of technologies and measurement methods, it was slightly corrected.

Other information about the planet Earth

The surface area of ​​the Earth is 510,072,000 km², of which 361,132,000 km² are covered by water, which is 70.8% of the Earth's surface. The land area is 148,940,000 km², which is 29.2% of the Earth's surface area. Due to the fact that water covers much more of the surface of the planet, it was more logical to call our planet Water.
The volume of the Earth is 10.8321 x 10 11 km³.
The highest point on the earth's surface above sea level is Mount Everest, which is 8848 m high, and the deepest place in the world's oceans is the Mariana Trench, its depth is 11022 m. Well, if we give average values, then the average height of the Earth's surface above sea level is 875 m , and the average depth of the ocean is 3800 m.
Acceleration free fall it is the acceleration of gravity in different parts of the planet will be slightly different. At the equator g= 9.780 m/s² and gradually increases, reaching g=9.832 m/s² at the poles. The average value of the gravitational acceleration is assumed to be g = 9.80665 m/s²
The composition of the atmosphere of planet Earth: 1) 78.08% nitrogen (N2); 2) 20.95% oxygen (O2); 3) 0.93% argon (Ar); 0.039% - carbon dioxide (CO2); 4) 1% water vapor. Other elements from Mendeleev's periodic table are also present in small amounts.
Planet Earth is so big and interesting that, despite how much we already know about the Earth, it never ceases to amaze us with those mysteries and unknowns that we continue to face.

For two halves. In this regard, it is not surprising that people are wondering: what is the equator? The equator is an imaginary line that exactly intersects the surface of our Earth with a plane that is considered perpendicular to the axis of rotation of the planet and passes directly through its center. From Latin, the word "aequator" is translated as "equalizer". This line is a conditional reference point geographical latitude, equal to 0 degrees at the equator.

The length of the equator is 40,075.676 km, the other lines (parallels) are always less than its length. Throughout his line, day is constantly equal to night. It is the equator that divides our planet into two hemispheres, Southern and Northern. Twice a year, on the days of the autumn and spring equinoxes, the sun is at its zenith above it. falls on March 20-21, and autumn - on September 23. These are directly overhead, and objects don't cast shadows.

The length of the equator was calculated by scientists using the formula 2πR, despite the fact that the Earth is not spherical, but elongated in the form of an ellipse (a ball flattened at the poles). Nevertheless, the radius of our planet is conventionally taken as the radius of the ball. The length of the earth at the equator is the longest line encircling the earth. An interesting fact is that it crosses 14 states.

If you move from towards the east, then the equator crosses states such as Sao Tome and Principe in Atlantic Ocean, then Gabon, Congo, Kenya, Uganda, Somalia in Africa. Moving along the Indian Ocean, it passes through the Maldives and Indonesia. In the Pacific Ocean, the equator crosses Kiribati and the Baker Islands, which belong to the United States, then Ecuador, Colombia and Brazil, which are located on the South American continent. These countries are the hottest on the planet.

The length of the equator was first calculated by the ancient Greek scientist Eratosthenes, who was not only a great mathematician, geographer, poet, but also an astronomer. By measuring the time it took the sun's rays to reach the bottom of the well, the scientist was able to calculate the radius of the globe and find out how long the equator was. These calculations are very approximate, but they gave much to subsequent generations of scientists to more accurately calculate the length of this imaginary line. Eratosthenes of Cyrene was born in 276 BC. and died in 194 BC.

He was one of the greatest scientists ancient world. He was born in the Greek city of Cyrene and, at the invitation of King Ptolemy III Euergetes, was in charge of the Library of Alexandria. This great scientist died of hunger, in terrible poverty, but went down in history as an insightful researcher with an extraordinary approach to science. The length of the equator according to Eratosthenes was 252 thousand stades, which is 39,690 km. The creator of mathematical and physical geography, Eratosthenes made great discoveries in many areas. Modern man it is very difficult to understand how a scientist, without any instruments, calculated the length of the equator, with an error of only 386 kilometers.

Many mathematicians and astronomers subsequently also tried to calculate the length of the equator. At the beginning of the 17th century, the Dutchman Snellius proposed to calculate this value without taking into account the obstacles encountered. In the XVIII century, scientists from France were seriously engaged in such calculations. The Russians also did not stand aside and made their contribution to science, which made it possible to determine what is the length of the earth along the equator. Director V.Ya. Struve carried out these measurements in degrees in the period from 1822 to 1852, and in 1941 the Soviet geodesist F.N. Krasovsky was able to calculate the length of the earth's ellipse, from which modern scientists around the world start, since it is recognized as a standard.

Now you know that in the fabulous Universe of our distant ancestors, the Earth did not even resemble a ball. The inhabitants of Ancient Babylon represented it as an island in the ocean. The Egyptians saw it as a valley stretched from north to south, in the center of which was Egypt. And the ancient Chinese at one time depicted the Earth as a rectangle ... You smile, imagining such an Earth, but how often have you thought about how people guessed that the Earth is not an infinite plane or a disk floating in the ocean? When I asked the guys about this, some said that people learned about the sphericity of the Earth after the first trips around the world, while others recalled that when a ship appears from behind the horizon, we first see the masts, and then the deck. Do such and some similar examples prove that the Earth is a sphere? Hardly. After all, you can go around and around ... a suitcase, and the upper parts of the ship would appear even if the Earth had the shape of a hemisphere or looked like, say, a ... log. Think about it and try to depict what is said in your drawings. Then you will understand: the examples given show only that The earth is isolated in space and possibly spherical.

How did you know that the Earth is a sphere? Helped, as I already told you, the Moon, or rather - lunar eclipses, during which the round shadow of the Earth is always visible on the Moon. Arrange a small "shadow theater": illuminate objects in a dark room different shapes(triangle, plate, potato, ball, etc.) and notice what kind of shadow they get on the screen or just on the wall. Make sure only the ball always casts a circle shadow on the screen. So, the Moon helped people to know that the Earth is a sphere. To this conclusion, scientists Ancient Greece(for example, the great Aristotle) ​​came as early as the 4th century BC. But for a very long time, the "common sense" of a person could not come to terms with the fact that people live on a ball. They could not even imagine how it is possible to live on the “other side” of the ball, because the “antipodes” located there would have to walk upside down all the time ... But wherever a person is on the globe, a stone thrown up everywhere will be under the influence of force gravity of the Earth to fall down, that is, to the earth's surface, and if it were possible, then to the center of the Earth. In fact, people, of course, nowhere, except for circuses and gyms, do not have to walk upside down and upside down. They go anywhere on the Earth normally: earth's surface under their feet, and the sky above their heads.

Around 250 BC, a Greek scholar Eratosthenes first accurately measured the globe. Eratosthenes lived in Egypt in the city of Alexandria. He guessed to compare the height of the Sun (or its angular distance from a point overhead, zenith, which is called - zenith distance) at the same time in two cities - Alexandria (in northern Egypt) and Syene (now Aswan, in southern Egypt). Eratosthenes knew that on the day of the summer solstice (June 22) the Sun was at noon illuminates the bottom of deep wells. Therefore, at this time the Sun is at its zenith. But in Alexandria at this moment the Sun is not at its zenith, but is separated from it by 7.2 °. Eratosthenes obtained this result by changing the zenith distance of the Sun with the help of his simple goniometric tool - the scaphis. This is just a vertical pole - a gnomon, fixed at the bottom of a bowl (hemisphere). The skafis is installed so that the gnomon assumes a strictly vertical position (directed to the zenith). The pole illuminated by the sun casts a shadow on the inner surface of the skafis divided into degrees. So at noon on June 22 in Siena, the gnomon does not cast a shadow (the Sun is at its zenith, its zenith distance is 0 °), and in Alexandria, the shadow from the gnomon, as can be seen on the scale of the skafis, marked a division of 7.2 °. At the time of Eratosthenes, the distance from Alexandria to Syene was considered equal to 5000 Greek stadia (about 800 km). Knowing all this, Eratosthenes compared an arc of 7.2 ° with the entire circle of 360 ° degrees, and a distance of 5000 stadia - with the entire circumference of the globe (we denote it by the letter X) in kilometers. Then from the proportion

it turned out that X = 250,000 stages, or about 40,000 km (imagine this is true!).

If you know that the circumference of a circle is 2πR, where R is the radius of the circle (and π ~ 3.14), knowing the circumference of the globe, it is easy to find its radius (R):

It is remarkable that Eratosthenes was able to measure the Earth very accurately (after all, even today it is believed that the average radius of the Earth 6371 km!).

But why is it mentioned here average radius of the earth, Aren't all spheres the same radius? The fact is that the figure of the Earth is different from the ball. Scientists began to guess about this back in the 18th century, but what the Earth really is - is it compressed at the poles or at the equator - it was difficult to find out. To understand this, the French Academy of Sciences had to equip two expeditions. In 1735, one of them went to carry out astronomical and geodetic work in Peru and did this in the equatorial region of the Earth for about 10 years, and the other, Lapland, worked in 1736-1737 near the Arctic Circle. As a result, it turned out that the length of the arc of one degree of the meridian is not the same at the poles of the Earth and at its equator. The meridian degree turned out to be longer at the equator than at high latitudes (111.9 km and 110.6 km). This can only happen if the Earth is compressed at the poles and is not a ball, but a body close in shape to spheroid. At the spheroid polar radius less equatorial(for the terrestrial spheroid, the polar radius is shorter than the equatorial one by almost 21 km).

It is useful to know that the great Isaac Newton (1643-1727) anticipated the results of the expeditions: he correctly concluded that the Earth is compressed, because our planet rotates around its axis. In general, the faster the planet rotates, the greater must be its compression. Therefore, for example, the compression of Jupiter is greater than that of the Earth (Jupiter manages to make a revolution around the axis with respect to the stars in 9 hours and 50 minutes, and the Earth only in 23 hours and 56 minutes).

And further. The true figure of the Earth is very complex and differs not only from a ball, but also from a spheroid. rotation. True, in this case we are talking about the difference not in kilometers, but ... meters! Scientists are engaged in such a thorough refinement of the figure of the Earth to this day, using for this purpose specially carried out observations with artificial satellites Earth. So it is quite possible that someday you will have to take part in solving the problem that Eratosthenes took up a long time ago. This is very what people need a business.

What is the best way to remember the figure of our planet? I think that for now it is enough if you imagine the Earth as a ball with an "additional belt" put on it, a kind of "slap" on the equator region. Such a distortion of the figure of the Earth, turning it from a sphere into a spheroid, has considerable consequences. In particular, due to the attraction of the "additional belt" by the Moon, the earth's axis describes a cone in space in about 26,000 years. This movement earth's axis called precessional. As a result, the role of the North Star, which now belongs to α Ursa Minor, is alternately played by some other stars (for example, α Lyra - Vega will become it in the future). In addition, because of this precessional) movements of the earth's axis Zodiac signs more and more do not coincide with the corresponding constellations. In other words, 2000 years after the era of Ptolemy, the "sign of Cancer", for example, no longer coincides with the "constellation of Cancer", etc. However, modern astrologers try not to pay attention to this ...