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 largest number 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.

There are currently fourteen countries on the equator. The political map of the world is constantly changing: countries appear and disappear, their borders can expand or shrink. 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.

The high temperature 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.

This is an 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. Consequently, any spacecraft that are launched from here will already, as it were, start at supersonic speed.

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

Without this imaginary line, there would be no way for people to pinpoint the location of the island or even famous city. All planes and ships are guided by a conditional map of latitudes, parallels, where the key place is played by a line that crosses the Earth in exactly two halves.

A river called the Congo crosses the median line of the Earth as many as twice.

What is the equator, its characteristics

Calculate the length of the Earth's equator

Conclusion

The equator is 40,075 kilometers long. So that you can appreciate how huge this is, let's compare it with the mileage of an ordinary car. On average, it takes a typical Nissan Juke three years to cover that distance. This line divides the planet into the northern and southern hemispheres. It is here that the wettest regions of the planet are located, where the largest number of species of animals and plants, which we used to call exotic, are concentrated. It is here, in countries with a very warm climate, that the largest number of tourists come.

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 unlimited 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? Unlikely. 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 of various shapes in a dark room (triangle, plate, potato, ball, etc.) and notice what kind of shadow they produce 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 no matter where a person was on the globe, everywhere a stone thrown up will fall down under the influence of the Earth's gravity, that is, on 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 walk normally anywhere on the Earth: the earth's surface is under their feet, and the sky is 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 in such a way that the gnomon takes 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 from artificial satellites of the 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 something people really need.

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, alternately play some other stars (in the future it will be, for example, α Lyra - Vega). 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 ...

Like all planets solar system The earth has a spherical shape. Before talking about its exact dimensions, let's introduce some important geographical concepts.

The earth revolves around an imaginary straight line - the so-called earth's axis. The points of intersection of the earth's axis with the earth's surface are called poles. There are two of them: North and South. The line of intersection of the surface of the globe with a plane passing through the center of the Earth perpendicular to the earth's axis is called equator. Planes intersecting the earth's surface parallel to the plane of the equator form parallels, and the planes passing through two poles - meridians.

Due to rotation around its axis and the resulting centrifugal force, the Earth is slightly flattened at the poles and its semi-major axis (equatorial radius, r c) is almost 21.4 km greater than the distance from the center of the Earth to the poles. Such a ball flattened at the poles is called spheroid or ellipsoid of revolution.

In Russia, F. N. Krasovsky's ellipsoid is used for geodetic and cartographic work (named after the scientist under whose guidance the calculations were carried out). Its dimensions are:

equatorial radius - 6378.2 km,
polar radius - 6356.8,
meridian length - 40008.5 km,
equator length - 40075.7 km,
the surface area of the Earth is 510 million km 2.

In reality, the figure of the Earth is even more complicated. It deviates from the regular shape of a spheroid due to the inhomogeneous structure of the interior and the uneven distribution of mass. True geometric figure The earth is called geoid("earthlike"). A geoid is a figure whose surface is everywhere perpendicular to the direction of gravity, i.e. plumb.

The surface of the geoid coincides with the level surface of the World Ocean (mentally extended under the continents and islands). The rise and fall of the geoid above the spheroid is 500-100 m.

The physical surface of the Earth, complicated by mountains and depressions, does not coincide with the surface of the geoid, retreating from it for several kilometers. Gravity is constantly striving to level the surface of the Earth, to bring it into line with the surface of the geoid.

Earth... Such a sweet, dear planet for all mankind. How much do we know about her? Yes many. Is there a lot we don't know about her? A lot more than what we know. Our planet reveals its secrets quite reluctantly. To a large extent, this is because the secrets of the planet Earth, so to speak, are not only her personal, but these are secrets and cosmic, the secrets of the Universe.

As a cosmic body, the Earth is a planet revolving around the Sun along with other planets (Mercury, Venus, Mars, Jupiter, Saturn, Uranus, Neptune, Pluto).

The main parameters of the planet Earth

The average distance from the Earth to the Sun is 149597870 km.
The average distance from the Earth to the Moon is 384,400 km.
The time of the complete revolution of the Earth around its axis (sidereal day) is 23 hours 56 minutes. 4.09 sec.
The period of revolution of the Earth around the Sun (tropical year) - 365.25 days
The average speed of the Earth's orbit is 29.76 km/sec.
Weight 6,000,000,000,000 billion tons.

Dimensions of the globe (ellipsoid):

Semi-major axis (equatorial radius), a - 6378.2 km.
Semi-minor axis (polar radius), in - 6356.9 km.
Compression c \u003d (a-b) / a - 1: 298.3
The average radius of the Earth taken as a ball is 6371.2 km.
The length of the meridian is 40008.6 km.
The length of the equator is 40075.7 km. (diameter of the equator - 12756 km.)
The surface of the Earth is 510,100,000 sq. km.
The average height of land above ocean level is 875 m.
The average depth of the world ocean is 3800 m.
The highest land height above ocean level is 8848 m. (Mount Everest)
The greatest depth of the world ocean - 11022 m. (Marian Trench)

Distribution of land and water on the globe

surface of the globe	North hemisphere		Southern Hemisphere		Earth as a whole
surface of the globe	million sq. km	%	million sq. km	%	million sq. km	%
Land	100	39	49	19	149	29
Water	155	61	206	81	361	71
Total	255	100	255	100	510	100

*) Data taken from the Small Atlas of the World, Moscow Publishing House, 1980.

From these data follows the long-recognized fact that the Earth is slightly compressed at the poles. However, there is evidence that the Earth has a melon-like shape, i.e. compressed along the equator so that along the vertical axis it is several tens of kilometers larger than along the equatorial axis. But we do not consider this hypothesis of scientists from the California Institute of Technology and we present it here solely for the information of exotic lovers.

What is the actual shape of the Earth according to modern ideas of official science? From the given data (Small Atlas of the World) it follows that the Earth is a ball with deviations from the mathematically exact form. The hand does not rise to call the Earth an ellipsoid: the difference between the major and minor axes of the ellipsoid is too tiny for the size of the Earth. Therefore, in science, the shape of the Earth is called the geoid. This should be understood in such a way that the Earth has the shape of the Earth.

True, for people who day after day observe the objects and phenomena of nature around them and do not think about their essence, causes, and, moreover, origin, it does not matter what shape the planet Earth has. They do not see the amazing beauty and great wisdom of the world around them, they do not have questions about why everything is so arranged on Earth, and there is no desire to learn anything about the planet on which they live. Their interests are limited to the circle of everyday worldly concerns. There are many such people, they are with us. I want to say right away: our story is not for them. Our story is for those people who are interested in everything about the Earth: its origin and age, its beauty and richness, its uniqueness as a cosmic body and as a place of origin of life and the stay of our human civilization. Our story is for people who are not just interested, but deeply concerned about the future of the Earth, its ecology, its entire biosphere, and, therefore, the future of mankind.

Origin of the Earth

At the beginning of our story about the Earth and the geospheres, it is necessary to say how the Earth came into being. The question of the origin of the Earth is very complicated, because here we can talk about the origin of the entire solar system and even the entire galaxy, called the Milky Way. There are many scientific hypotheses and just assumptions on this topic. Suffice it to mention the hypothesis of the so-called big bang. We note right away that there is still no single coherent theory of the origin of the Universe and the Solar System. Various hypotheses put forward by different scientific schools and individual scientists often contradict each other. You can dwell, for example, on the following hypothesis of the origin of the solar system and the Earth:

Formation of the Sun and the planets of the solar system. and the planets formed about five billion years ago from a huge cosmic cloud of gas and dust (1). This cloud had a flattened, lenticular shape - the shape of a disk. Scientists believe that both this disk and the Sun were formed from the same rotating mass of interstellar gas - the protosolar nebula. The least studied is the earliest stage in the origin of the solar system - the separation of the protosolar nebula from the giant parent molecular cloud belonging to the Galaxy.

Under the influence of gravitational forces of attraction, the cloud began to shrink, and a rotating disk of substances was formed, the main part of which gathered in the center (2). The central core was shrinking, attracting more and more matter, and at some point in its depths, under the influence of huge compression pressure, a nuclear reaction (3) started - a star lit up, the Sun arose. The rest of the matter churned into smaller formations of stones and clots of gas - this is how the planets were formed. The solar system has taken modern look (4).

At the initial stage of its formation, the Sun was very hot, which caused the evaporation of a large part of the light volatile substances (mainly hydrogen and helium) into space, which were in the region where the Earth was formed. In other words, the protoplanetary nebula around the Sun was divided into two parts that were different in composition and temperature: the one closest to the Sun contained fewer light elements and had sufficient saturation in heavy elements, in contrast to the more distant one, depleted in heavy elements and consisting mainly of light gases. In the more distant and colder regions of the future solar system, light matter could condense to form, under the influence of gravity, giant gaseous planets - "gas giant planets", such as Jupiter and Saturn.

Under the action of gravitational forces, the matter of the solar nebula also accumulated in the inner part of the nebula - here the formation of the Earth and other terrestrial planets took place. But because of the enormous temperature, the matter was in a molten state; denser substances, such as iron, nickel and their compounds, rushed to the center of the planet, while lighter substances, such as silicates of various metals, from which rocks subsequently formed, remained on the surface. This process is called gravitational differentiation. At the end of this process, the temperature on the Earth gradually dropped so much that the process of solidification began.

It should be noted that this scenario is only one of the theoretical scenarios for the formation of the Earth. For example, in the 1940s, Academician O.Yu. Schmidt put forward a hypothesis that has become generally accepted about the formation of the Earth and other planets from cold solid pre-planetary bodies - planetesimals. Planetesimal (from the English planet - planet and infinitesimal - infinitesimal) - a body representing an intermediate step in the formation of a planet from a protoplanetary gas-dust cloud. We will consider in more detail the main points of the theories of the formation of planets in a separate chapter devoted to the origin of the solar system.

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Equator in Latin means "to equalize". It is generally accepted that the equator is a conditional circle dividing the globe into northern and southern hemisphere, and the longest circle (or parallel) of the Earth that is perpendicular to its axis of rotation.

The equator is the starting point for determining the coordinates of any place on the planet. Without it, it would be impossible to determine the exact position in space of any geographical objects or it was extremely difficult.

Everyone has long known that, to be academically accurate, the Earth is actually not a sphere, but a geoid. Geoid- a body, in its proportions resembling a sphere, but not being one. Indeed, at the highest point on the planet, the height is 8,848 m (Mount Everest) and at the lowest - 10,994 m (Marian Trench) relative to sea level.

That is, if you take into account all the differences in height, then any calculation will cause a lot of problems. Therefore, in the international community, for ease of calculation, our planet is considered to be a sphere. Including the equator is considered a circle, although in fact it is not.

According to the international standard WGS-84 the radius of the earth is 6,378,137 m. According to another standard, IAU-1976 and IAU-2000, the radius of the Earth is 6,378,140 m. The difference of three meters is due to the difference in approaches and methods of calculation. However, the length of the equator is 40,075 km, whichever of the standards we take, because after calculating the circumference using the formula l=2πR, the difference will be only in the second decimal place.

History of calculations

The first attempts to calculate the length of the equator were made in ancient Greece by Eratosthenes. Although, in fact, if we take the world known at that time, he considered not the equator, but the radius of the Earth in the region of Europe, which is tied to the circumference through 2πR. At that time there was no scientific concept about the earth as a planet.

In order not to go into the details of the experiment, we will explain its essence. Eratosthenes determined that at the moment when in the city of Siena (now Aswan) the Sun is at its zenith and illuminates the bottom of the well, at the same time in Alexandria it "lags behind" by about 7 degrees and does not illuminate the bottom of the well. Which, in turn, is approximately 1/50 of the circle. Now, knowing the distance from Syene to Alexandria (it was about 5000 stadia), it was possible to determine the circumference.

The more surprising are the results of the calculations. Eratosthenes considered the length of the equator to be 252,000 stadia. But since during his life he lived both in Alexandria (Egypt) and in Athens (Greece), historians and geographers still cannot say with certainty which stages Eratosthenes used in the calculations. If Greek, then according to Eratosthenes, the radius was 7,082 km, if Egyptian - 6,287 km. Whatever result you took for your time, it was an incredibly accurate radius calculation.

Later attempts to calculate the length of the equator were adopted by many European scientists. For the first time, he spoke about the possible averaging of the radius for the convenience of calculations in the calculations Dutchman Snellius. In the 17th century, he proposed to calculate the radius without taking into account natural barriers. In the XVIII century, France (the first of the countries) switched to the metric system of measurement. Moreover, when calculating the length standard, French scientists tied it to the radius of the Earth.

The calculation was tied to the length of a mathematical pendulum, the half-period of which is one second. For its time, the idea was groundbreaking. However, when traveling to the southern latitudes, the French cartographer Jean Richet noticed that the oscillation period increased. The reason was that the Earth is a geoid and the force of gravity drops closer to the equator.

Research in Russia

AT Russian Empire studies were also carried out to determine the shape, length and other parameters of the Earth. Perhaps the largest and most important of these was project "Russian arc" or "Arc Struve" under the leadership of Friedrich Georg Wilhelm Struve (Vasily Yakovlevich Struve). To carry out measurements, 265 triangulation points were built, which were 258 triangles with a common side. The length of the arc was 2820 km, which is 1/14 of the circumference of the globe. The arc at that time passed through the territory of Norway, Sweden and the Russian Empire. The study was financed personally by Emperor Alexander I, and then by Nicholas I.

This project was the first of the measurements of the Earth, which accurately determined its shape and parameters. When measuring the parameters of the Earth by satellite methods in the 20th century, the Struve measurement error was 2 cm.

In the Soviet Union, the geodetic school also made attempts to calculate the parameters of the Earth's ellipsoid. In 1940, thanks to the work of A.N. Izotov and F.N. Krasovsky was calculated and adopted as the standard for geodetic work in the USSR, the Krasovsky ellipsoid, which determines all the main parameters of the Earth's ellipsoid. According to Krasovsky, the following parameters are accepted:

The small radius of the Earth (polar radius) is 6,356.863 km.
Large radius (equatorial) 6,378.245 km.
The length of the equator is 40,075.696 km.
The surface area of the Earth is 510,083,058 km2.

These facts will be interesting to know:

A length of 40,075 km, on average, is covered by a car in Russia in two years.
The earth's rotational speed at the equator is 465 meters per second. faster speed sound. Related to this is the launch preference spaceships closer to the equator. At launch, the rocket is already moving at supersonic speed relative to the Earth. This saves a lot of fuel.
The only glacier on the equator is the Cayamba volcano cap in Ecuador.
When moving from the pole to the equator, objects and bodies lose 0.53% of their mass. This is due to the distance from the center of mass of the Earth.
Not a single traveler has yet managed to pass along the earth's part of the equator.
In Brazil, in the city of Macapa, there is a football stadium, in the middle of which the equator line runs.

Video

You will learn a lot of useful information about the Earth from this video.