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.
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).
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.
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.
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.
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 ocean depth 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.
Therefore, I will talk about the magnitude of the earth's diameter and the equator. Considering, as I said earlier, that the earth's shape is not perfectly spherical, it is customary to consider the equator to be a circle. At the equator, the diameter is 12 thousand 756 kilometers, and at the poles, naturally, it is slightly less - 43 kilometers. For example, in 2007 it turned out that since 2000, the diameter of the planet has become smaller by five millimeters.
It was thanks to the rotation that the bulge around the equator was formed. Based on the premise that the Earth is spherical and the circumference is 360 degrees, we find the distance (chord) between two points located at a distance of a degree and multiply by 360. Simple? Scientists calculated the length of the equator 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).
40,075 kilometers is the length of the equator. The equator divides the surface of the globe into the Northern and Southern Hemispheres and serves as the origin of geographic latitude. 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. However, reaching the border between the Northern and Southern Hemispheres still did not make it possible to determine the length of the equator. By measuring the time during which the sun's rays reached the bottom of the well, the scientist was able to calculate the radius of the globe and find out how long the equator is.
As a result of internal processes in the bowels of the planet, the core gradually warms up and hydrogen is released. 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. So over time the length of the equator will increase.
What is the circumference of the Earth in kilometers - how was this value calculated? What is the circumference of the earth along the equatorial line or along the meridian? This is a circular line encircling the planet and passing through its center. The equator is perpendicular to the earth's axis of rotation. The scientist measured the angle and found that its value was 1/50 of the whole circle, equal to 360 degrees. It turned out that at the equator the degree has a shorter length. Thus, it was found that the polar circumference of the Earth is 21.4 kilometers smaller than the equator circumference.
Which of us can remember from memory how many kilometers the circumference of the Earth is at the equator? Who knows when and how the circumference of the earth was first measured? Having measured this angle using astronomical instruments, the scientist found that it was 1/50 of a full circle. 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).
The equator line is perpendicular to the axis of rotation of our planet and is located at an equal distance from both poles. This helped him calculate the length of the radius of the Earth and, accordingly, the equator thanks to the formula for circumference. In addition, in other articles, Eratosthenes calculated the Equator using the angle of inclination of the shadow when the Sun illuminated the bottom of the well!! 1. A line passing along the surface of the Earth (equator) cannot pass through the center of the Earth, as you wrote.
Eratosthenes allegedly measured angles with an accuracy of arc seconds and the difference in latitudes of Alexandria was 7° 6.7′, that is, 7x60 = 420 + 6.7 = 426.7 nautical miles (arc minutes). It is not clear what stage Eratosthenes used to measure distances, etc. The first angle rests on an arc from the end of the shadow of the gnomon to its base, and the second on an arc with its center at the center of the Earth, drawn from Siena to Alexandria. These arcs are similar to each other because they have equal angles. And what relation does the arc on the bowl have to its circle, the same relation does the arc from Siena to Alexandria have.
Here's a simple way to measure the circumference (and diameter) of the Earth that was most likely used by ancient astronomers. The ideal choice would be a Star that is close to the celestial axis of the North Pole (indicating the center of the Earth's axis of rotation). The angular diameter of the Moon and the Sun is almost the same: 0.5 degrees. If one of our astronomers made this measurement from a location at point (A) near Giza (30 0 C), the star Mizar should have appeared about 41 degrees above the local horizon.
The total length of this arc exceeded 2800 km. It covered more than 25 degrees, which is almost 1/14 of the earth's circumference. Clairaut's theorems establish a connection between the shape of the Earth, its rotation and the distribution of gravity on its surface, thereby laying the foundations for a new branch of science - gravimetry. Geoid is a conditional surface of equal potential (equilibrium surface), coinciding with the surface of freely resting water in the open ocean. It is obvious that the relief of the lithosphere in the oceans is located below the surface of the geoid, and on the continents it is higher (they say: “height above sea level”).
More recently, in 1862, the German scientist P. Ioseliani, determining the “depth of the thickness of the globe,” received 4536.8 km, which is 11/2 times less than the actual value. It’s hard to believe, but back in 1876, a brochure was published in St. Petersburg entitled: “The Earth is Stationary, a popular lecture proving that the globe does not rotate either around its axis or around the Sun. In 1841, the German astronomer F. Bessel, using degree measurements, calculated the radius of the Earth and its compression at the poles, i.e., he obtained figures characterizing the main elements of the Earth's ellipsoid. We also have to assume that the northern and southern hemispheres, as shown by the Russian scientist A. A. Ivanov, are not completely symmetrical relative to the equatorial plane.
In size it surpasses only Mercury, Mars and Pluto. When the area around the North Pole faces the Sun, it is summer in the Northern Hemisphere and winter in the Southern Hemisphere. When the area around the South Pole faces the Sun, it is the other way around. Meredian is half a circle, corresponds to _______ degrees and ________”, category “geography”.
Of course, as a result of such studies, Eratosthenes calculated the approximate length of the radius of the Earth, and therefore the equator. To calculate the Earth's equator, you need to know the radius of the planet. At the equator, latitude is zero. The length of the equator is one of the main characteristics of any planet.
To a first approximation, the Earth's magnetic field is a dipole, the poles of which are located next to the geographic poles of the planet.
21.3 kilometers - the equator is so farther from the center of the Earth than its poles. Due to rotation, the globe is flattened at the poles by 1/298 of its diameter. 35,786 kilometers - at this altitude above the equator the geostationary orbit is located, on which communication satellites “hang”. The signal travels back and forth at the speed of light in just a quarter of a second.
Due to the tilt of the earth's axis, the height of the Sun above the horizon changes throughout the year. For the Earth, the radius of the Hill sphere (sphere of influence of Earth's gravity) is approximately 1.5 million km [comm. 5]. This is the maximum distance at which the influence of the Earth's gravity is greater than the influence of the gravity of other planets and the Sun.
To measure the zenith distance of the Sun, Eratosthenes used a sundial - scaphis - as a goniometric instrument. The sun is 47 degrees 42 minutes.
In other words, the meter was defined as 1/10.000000 of the distance from the Earth's equator to the North Pole measured along the surface of the Earth's circumference (ellipsoid) through the longitude of Paris.
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.
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.
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:
These facts will be interesting to know:
You will learn a lot of useful information about the Earth from this video.
Where does the equator lie and what is it, what is its duration, and why did scientists even need to come up with this imaginary line? Let's talk about all this in more detail.
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The equator is a conventional line that runs exactly through the center of our planet. Geographical latitude of the equator- 0 degrees. It serves as a reference point and allows 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, night is always equal to day, without deviation even for a split second.
The equatorial zone receives the greatest amount of ultraviolet rays. Consequently, the further a point is from the conditional line, the less heat and light it receives. That is why the highest temperatures were recorded in the area of the conventional line.
To carry out various calculations, scientists need to identify special dividers of the planet, which are the equator, parallels and meridians.
These conditional lines make it possible to determine the position of various objects, enable planes to navigate in, and ships - to.
In addition, it is this strip 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 sciences such as geodesy or elementary geography, but also in astrology and astronomy.
The territories of fourteen states are currently located on the equator. The political map of the world is constantly changing: countries appear and disappear, their borders can expand or contract. Which states are we talking about:
According to the most accurate calculations, the length of the equator in kilometers is 40075 km. But the length of the Earth's equator in miles reaches 24901 miles.
As for such a concept as radius, it can be polar and equatorial. The dimensions of the first in kilometers reach 6356, and the second - 6378 km
All areas located in close proximity to this imaginary line have a warm and humid climate.
It is no coincidence that life is simply bustling in these areas. This is where the greatest concentration is concentrated variety of plant and animal species.
Equatorial forests are considered the densest in the world, and some of them are even impenetrable wilds, even taking into account all modern scientific achievements.
Precipitation in the equatorial zone is almost daily and very heavy. It is precisely because everything that is located and grows here shines with a wide variety of colors.
On the planet there is a volcano called Wolf. So, the fact is that it is currently active and, interestingly, is on both sides of the conventional line.
Attention! The average annual temperature in this zone reaches 25-30 degrees Celsius.
High temperatures all year round make the countries that are in this region an ideal holiday destination for tourists. This is especially true for popular resorts located in the Maldives, where millions of vacationers 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 conventional line reaches more than 460 meters per second.
The speed of sound reaches only 330 meters per second. Consequently, any spacecraft that are launched from here already seem to launch at supersonic speed.
We talked about the extent of the equator, what role it plays in modern human life. As many as three countries are named as part of it.
Without this conditional line, people would not be able to accurately determine the location of the island or even famous city. All planes and ships are guided by a conventional map of latitudes and parallels, where the key place is played by a line that crosses the Earth in exactly two halves.
The Congo River crosses the Earth's midline twice.
What is the equator, its characteristics
Calculate the length of the Earth's equator
The length of the equator is 40,075 kilometers. So that you can appreciate how huge this is, let’s compare it with the mileage of a regular passenger car. On average, a regular Nissan Juke needs three years to cover a similar 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 are accustomed to call exotic, are concentrated. It is here, in countries with a very warm climate, that the largest number of tourists come.
