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 man’s desire for knowledge reveals all the secrets of our world.

General information about planet Earth

Let's remember what we know about planet Earth. Earth is the only inhabited planet in our solar system, even moreover, the only one on which there is life. Earth is the third planet, counting from the Sun, before Earth there are two more planets Mercury and Venus. The Earth rotates around the Sun and the inclination of the rotation axis relative to the Sun is 23.439281°, thanks to this inclination we can observe the change of seasons throughout the year. The distance from the earth to the sun is 149,600,000 km; for a stream of light to cover 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 384,400 km. The speed of the Earth's movement in its orbit is 29.76 km/sec. The Earth makes a complete rotation on its axis in 23 hours 56 minutes and 4.09 seconds. For convenience, it is generally accepted that there are 24 hours in a day, but to compensate for the remaining time, another day is added to the calendar 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; a leap year has 29 days. There are 365 days in a year and 366 days in a leap year, this is a complete cycle of changing seasons (winter, spring, summer, autumn).

Earthly dimensions and parameters

Now let's move from space to planet Earth itself. In order for life to arise on the planet, there must be many factors and conditions that create a favorable 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 an organism the planet Earth is. There is nothing superfluous, everything has its place, and everyone has their own important role to play.

The structure of planet Earth

There are a total of 8 planets in our solar system, 4 of which belong to the terrestrial planets and 4 to the gas group. Planet Earth is the largest terrestrial planet and has the greatest mass, density, magnetic field and gravity. The structure of the Earth is not homogeneous, and it can be conditionally divided into layers (levels): the earth's crust; mantle; core.
Earth's crust – the uppermost layer of the Earth’s solid shell, 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 range from 5 - 75 km deep into the Earth. This range depends on the location of measurements, for example, on the ocean floor the thickness is minimal, and on continents and mountain ranges it is 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 on the ocean floor, and the uppermost sedimentary layer. The sedimentary layer is constantly being formed and modified, and humans play an important role in this.
Mantle - the layer next after 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 thickness of the mantle reaches 2900 km. The upper layer of the mantle, which is 900 km, is called magma. Magma is molten minerals, and the output of liquid magma is called lava.
Core - This is the center of planet Earth, consists mainly of iron and nickel. The radius of the earth's core is approximately 3500 km. The core is also divided into an outer core with a thickness of 2200 km, which has a liquid structure and an inner core with a radius of about 1300 km. The temperature in the center of the core is close to 10,000 °C; on the surface of the core, the temperature is significantly lower than 6,000 °C.

Shape of the Earth. Diameter of the Earth. Earth's mass. Age of the Earth.

If you ask the question, “What is the shape of the Earth?”, we will hear possible answers: round, sphere, ellipsoid, but this is not entirely true; a special term Geoid was introduced to denote the shape of the Earth. A geoid is essentially an ellipsoid of revolution. Determining the shape of the planet made it possible to accurately determine the diameters of planet Earth. Yes, it is precisely the diameters of the Earth that, due to its irregular shape, 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 it is slightly less than 40,007.86 km.
The mass of the Earth is a rather relative quantity that 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 increases annually by approximately 40,000 tons. But due to the dispersion of gases into outer space, the mass of the Earth decreases by about 100,000 tons per year. Also, the loss of Earth's mass is affected by an increase in temperature on the planet, which contributes to more intense thermal movement and the leakage of gases into space. The smaller the Earth's mass becomes, the weaker its gravity and the more difficult it becomes to maintain an atmosphere around the planet.
Thanks to the radioisotope dating method, scientists were able 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, and was subsequently slightly adjusted with the development of technology and measurement methods.

Other information about planet Earth

The Earth's surface area is 510,072,000 km², of which water spaces occupy 361,132,000 km², 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 name 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, whose height is 8848 m, and the deepest place in the world's oceans is considered to be 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.
The acceleration of gravity, also known as the acceleration of gravity, will be slightly different in different parts of the planet. 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 acceleration due to gravity is taken to be g = 9.80665 m/s²
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 quantities.
Planet Earth is so large and interesting that, despite how much we already know about the Earth, it never ceases to amaze us with the secrets and unknowns that we continue to encounter.

Earth, with an average distance of 149,597,890 km from the Sun, is the third and one of the most unique planets in the solar system. It formed about 4.5-4.6 billion years ago and is the only planet known to support life. This is due to a number of factors, such as atmospheric composition and physical properties such as the presence of water, which occupies about 70.8% of the planet's surface, allowing life to flourish.

Earth is also unique in that it is the largest of the terrestrial planets (Mercury, Venus, Earth and Mars), which are composed of a thin layer of rock, compared to the gas giants (Jupiter, Saturn, Neptune and Uranus). Based on mass, density, and diameter, Earth is the fifth largest planet in the entire solar system.

Dimensions of the earth: mass, volume, circumference and diameter

Terrestrial planets (Mercury, Venus, Earth and Mars)

As the largest of the terrestrial planets, Earth has an estimated mass of 5.9722±0.0006×10 24 kg. Its volume is also the largest of these planets at 1.08321×10¹² km³.

In addition, our planet is the densest of the terrestrial planets, as it consists of a crust, mantle and core. The Earth's crust is the thinnest of these layers, while the mantle makes up 84% of the Earth's volume and extends 2,900 km below the surface. The core is the component that makes the Earth the densest. It is the only terrestrial planet with a liquid outer core surrounding a solid, dense inner core.

The average density of the Earth is 5.514×10 g/cm³. Mars, the smallest of the Earth-like planets in the solar system, has only about 70% of the density of Earth.

Earth is also classified as the largest of the terrestrial planets in terms of circumference and diameter. The equatorial circumference of the Earth is 40,075.16 km. It is slightly smaller between the North and South Poles - 40,008 km. The diameter of the Earth at the poles is 12,713.5 km, and at the equator - 12,756.1 km. By comparison, the largest planet in the solar system, Jupiter, has a diameter of 142,984 km.

Shape of the Earth

Hammer-Aitov projection

The circumference and diameter of the Earth are different because its shape is an oblate spheroid or ellipsoid instead of a true sphere. The planet's poles flatten slightly, resulting in a bulge at the equator and therefore a larger circumference and diameter.

The Earth's equatorial bulge is 42.72 km and is caused by the planet's rotation and gravity. Gravity itself causes planets and other celestial bodies to collapse and form a sphere. This is due to the fact that it pulls the entire mass of the object as close as possible to the center of gravity (the earth's core in this case).

As the planet rotates, the sphere is distorted by centrifugal force. It is the force that causes objects to move outward from their center of gravity. When the Earth rotates, the centrifugal force is greatest at the equator, so it causes a slight outward bulge, giving that area a larger circumference and diameter.

Local topography also plays a role in the shape of the Earth, but on a global scale it is minor. The greatest differences in local topography around the world are Mount Everest, the highest point above sea level at 8,848 m, and the Mariana Trench, the lowest point below sea level at 10,994±40 m. This difference is only about 19 km, which is very insignificant on a planetary scale. If we consider the equatorial bulge, the highest point in the world and the place farthest from the center of the Earth is the summit of the Chimborazo volcano in Ecuador, which is the highest peak near the equator. Its height is 6,267 m.

Geodesy

To properly study the size and shape of the Earth, geodesy is used, a branch of science responsible for measuring the size and shape of the Earth through surveys and mathematical calculations.

Throughout history, geodesy has been an important branch of science as early scientists and philosophers attempted to determine the shape of the Earth. Aristotle is the first person credited with attempting to calculate the size of the Earth and is therefore an early surveyor. This was followed by the Greek philosopher Eratosthenes, who estimated the circumference of the Earth at 40,233 km, which is only slightly larger than the current measurement.

To explore the Earth and use geodesy, researchers often refer to the ellipsoid, geoid, and reference ellipsoid. An ellipsoid is a theoretical mathematical model that shows a smooth, simplified representation of the Earth's surface. It is used to measure distances on a surface without taking into account factors such as changes in elevation and landform. Given the reality of the earth's surface, surveyors use the geoid, a model of the planet that is constructed using global mean sea level and therefore takes elevation differences into account.

The basis of geodesy today is data that acts as guidelines for global geodetic work. Today, technologies such as satellites and global positioning systems (GPS) allow surveyors and other scientists to make extremely accurate measurements of the Earth's surface. In fact, they are so precise that they can measure the Earth's surface down to centimeters, providing the most accurate measurements of the Earth's size and shape.

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The earth is round - this is common knowledge. What else do we know about its shape and size? Which of us can remember from memory how many kilometers the circumference of the Earth is at the equator? What about the meridian? Who knows when and how the circumference of the earth was first measured? Meanwhile, these facts are extremely interesting.

The circumference of the Earth was first measured by Eratosthenes, who lived in the city of Siena. At that time, scientists already knew that the Earth is spherical in shape. Observing the celestial body at different times of the day, Eratosthenes noticed that at the same time the sun, being observed from Syene, is located exactly at the zenith, while in Alexandria on the same day and hour it deviates by a certain angle.

Observations were carried out annually. Having measured this angle using astronomical instruments, the scientist found that it was 1/50 of the full circle.

As you know, a complete circle is equal to 360 degrees. Thus, it is enough to know the chord of an angle of 1 degree (i.e., the distance between points on the Earth’s surface lying on rays with an angular distance between them of 1 degree). Then the resulting value should be multiplied by 360.

Taking the distance between the cities of Alexandria and Syene (5 thousand Egyptian stadia) as the length of the chord and assuming that these cities lie on the same meridian, Eratosthenes made the necessary calculations and named the figure that equaled the circumference of the Earth - 252 thousand Egyptian stadia.

For that time, this measurement was quite accurate, because there were no reliable methods for measuring the distance between cities, and the path from Siena to Alexandria was measured by the speed of the camel caravan.

Subsequently, scientists from different countries repeatedly measured and clarified the value that is the circumference of the Earth. In the 17th century, a Dutch scientist named Sibelius came up with a way to measure distances using the first theodolites - special geodetic instruments. This method was called triangulation and is based on constructing a large number of triangles and measuring the basis of each of them.

The triangulation method is still used today; the entire earth's surface is virtually divided and lined into large triangles.

Russian scientists also contributed to these studies. In the 19th century, the circumference of the Earth was measured by V. Ya. Struve, who led the research.

Until the mid-17th century, the Earth was considered a sphere of regular shape. But later, some facts were accumulated indicating a decrease in the force of gravity from the equator to the pole. Scientists fiercely debated the reasons for this; the most plausible theory was considered to be the compression of the Earth from the poles.

To test this hypothesis, the French Academy organized two independent expeditions (in 1735 and 1736), which measured the length of the equatorial and polar degrees, respectively, in Peru and Lapland. At the equator, the degree, as it turns out, is shorter!

Subsequently, other, more accurate measurements confirmed that the polar circle of the Earth is 21.4 km shorter than the equatorial one.

Currently, high-precision measurements have been made using the latest research methods and modern instruments. In our country, the data obtained by Soviet scientists A. A. Izotov and F. N. Krasovsky have been officially approved. According to these studies, the circumference of our planet along the equator is 40075.7 kilometers, along the meridian - 40008.55 km. The equatorial radius of the globe (the so-called semi-major axis) is equal to 6378245 meters, the polar (semi-minor axis) is 6356863 meters.

510 million sq. kilometers, of which only 29% belongs to land. The volume of the earth's "ball" is 1083 billion cubic meters. kilometers. The mass of our planet is characterized by the figure 6X10^21 tons. Of this, about 7% comes from water resources.

quoted1 > > > How many kilometers will it take to go around the Earth?

Fly around Earth: distance in kilometers for a flight around the third planet of the solar system, spheroidal shape, roundness, equator length and meridian.

Our planet is located in third position in terms of proximity to the Sun and is considered the largest of the terrestrial planets. Its radius is 6371 km, so in front of us is a large house. But is it possible to measure it from end to end? If you decide to bypass it completely, how many kilometers will you have to travel to return to your starting point? That is, what is the circumference of the Earth? In short, a little more than 40,075 km. But in reality everything is more complicated.

Recall that the shape of the planet plays a big role in calculating its size. The Earth is an oblate spheroid. If it were a perfect sphere, then you could go in any direction and cover the same distance.

In our case, the shape of the planet Earth is convex at the equatorial line, which was caused by rapid axial rotation. Its waist coverage is 47 km greater than that at the poles.

They began to believe in sphericity back in the days of Ancient Greece. Pythagoras especially strongly insisted on this. It all started with active trade between countries. They began to note that some stars could be observed in different places, and distant objects on the horizon hinted at planetary curvature. You can see the shape and appearance of the Earth in a photo from space.

In 240 BC. e. Erasophenes decided to measure the circumference of the earth by tracking the angles of shadows created by the Sun. Using trigonometric calculations, he gave indicators with an error of 2-20%.

In the 17th century we could boast better instruments and the idea of ​​a perfect sphere began to crumble. It was Isaac Newton who first suggested that the planet should be wider at the equatorial line. We were able to confirm his ideas with the advent of spacecraft in orbit and the receipt of photographs from space.

Equatorial and meridional path around the Earth

Oblate sphericity is displayed in the equatorial and meridional circles. If we calculate along the equator, we get 40075.017 km, but between the poles – 40007.86 km.

This also applies to calculating the radius. If you take as a basis the indicators from the center to the equatorial line, then the radius is 6378.1 km, and from the center to the pole – 6356.8 km. It seems that the difference is not big. But this still crosses our planet off the list of candidates for ideal spheres. Now you know everything about the circumference of the Earth, its size and shape.

Equator in Latin means "call". It is generally accepted that the equator is a conventional circle dividing the globe into the northern and southern hemispheres, and the longest circle (or parallel) of the Earth, 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 would be extremely difficult.

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

That is, if we take into account all the elevation differences, then any calculation will cause a lot of problems. Therefore, in the international community, for simplicity of calculations, our planet is usually considered a sphere. Including the equator is considered a circle, although in reality it is not one.

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 calculation methods. However, the length of the equator is 40,075 km, whichever standard we take, since after calculating the circumference using the formula l=2πR the difference will only be in the second decimal place.

Calculation history

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 did not calculate 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 of the Earth as a planet.

Without going into details of the experiment, let us 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 moment in time in Alexandria it “lags” 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 Siena to Alexandria (it was about 5000 stadia), it was possible to determine the circumference.

All the more unexpected 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 in both Alexandria (Egypt) and Athens (Greece), historians and geographers still cannot say with certainty which stages Eratosthenes used in his calculations. If Greek, then according to Eratosthenes the radius was 7,082 km, if Egyptian - 6,287 km. Whichever result you take for your time, it was an incredibly accurate calculation of the radius.

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 calculations Dutchman Snellius. In the 17th century, he proposed calculating the radius without taking into account natural obstacles. In the 18th century, France (the first country) switched to the metric measurement system. Moreover, when calculating the standard of length, French scientists were tied precisely to the radius of the Earth.

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

Research in Russia

In the Russian Empire, research was also carried out to determine the shape, length and other parameters of the Earth. Perhaps the largest and most important of them was project "Russian Arc" or "Struve Arc" under the leadership of Friedrich Georg Wilhelm Struve (Vasily Yakovlevich Struve). To carry out measurements, 265 triangulation points were constructed, 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 Earth. The arc at that time passed through the territory of Norway, Sweden and the Russian Empire. The research was personally financed by Emperor Alexander I, and later by Nicholas I.

This project was the first of the measurements of the Earth, which accurately determined its shape and parameters. When measuring Earth parameters using satellite methods in the 20th century, Struve’s 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's ellipsoid was calculated and adopted as a standard for geodetic work in the USSR, which determines all the main parameters of the Earth's ellipsoid. According to Krasovsky, the following parameters are accepted:

1. The Earth's minor radius (polar radius) is 6,356.863 km.
2. Large radius (equatorial) 6,378.245 km.
3. The length of the equator is 40,075.696 km.
4. The surface area of ​​the Earth is 510,083,058 km2.

These facts will be interesting to know:

1. A car in Russia travels 40,075 km on average in two years.
2. The Earth's rotation speed at the equator is 465 meters per second, which is faster than the speed of sound. This is related to the preference for launching spacecraft closer to the equator. At launch, the rocket is already moving at supersonic speed relative to the Earth. This saves fuel significantly.
3. The only glacier on the equator is the cap of the Cayamba volcano in Ecuador.
4. 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 Earth's center of mass.
5. Not a single traveler has yet managed to walk along the earth's part of the equator.
6. 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.