Modern knowledge about planet earth. Structure and composition of the earth

Earth is the third planet from the Sun and the largest of the terrestrial planets. However, it is only the fifth largest planet in terms of size and mass in the Solar System, but surprisingly, it is the densest of all the planets in the system (5.513 kg/m3). It is also noteworthy that the Earth is the only planet in the solar system that people themselves did not name after a mythological creature - its name comes from the old English word"ertha" which means soil.

It is believed that the Earth was formed somewhere around 4.5 billion years ago, and is currently the only known planet where the existence of life is possible in principle, and the conditions are such that life is literally teeming on the planet.

Throughout human history, people have sought to understand their home planet. However, the learning curve turned out to be very, very difficult, with many mistakes made along the way. For example, even before the existence of the ancient Romans, the world was understood as flat, not spherical. Second a clear example is the belief that the Sun revolves around the Earth. It was only in the sixteenth century, thanks to the work of Copernicus, that people learned that the Earth was actually just a planet orbiting the Sun.

Perhaps the most important discovery about our planet during the last two centuries is that the Earth is both ordinary and a unique place in the Solar System. On the one hand, many of its characteristics are rather ordinary. Take, for example, the size of the planet, its internal and geological processes: its internal structure is almost identical to the three other terrestrial planets in the solar system. On Earth, almost the same geological processes occur that form the surface, which are characteristic of similar planets and many planetary satellites. However, with all this, the Earth has simply a huge amount of absolutely unique characteristics, which strikingly distinguish it from almost all currently known terrestrial planets.

One of necessary conditions for the existence of life on Earth, without a doubt, is its atmosphere. It consists of approximately 78% nitrogen (N2), 21% oxygen (O2) and 1% argon. It also contains very small amounts of carbon dioxide (CO2) and other gases. It is noteworthy that nitrogen and oxygen are necessary for the creation of deoxyribonucleic acid (DNA) and the production of biological energy, without which life cannot exist. In addition, oxygen present in the ozone layer of the atmosphere protects the planet's surface and absorbs harmful solar radiation.

What's interesting is that a significant amount of the oxygen present in the atmosphere is created on Earth. It is formed as a byproduct of photosynthesis, when plants convert carbon dioxide from the atmosphere into oxygen. Essentially, this means that without plants, the amount of carbon dioxide in the atmosphere would be much higher and oxygen levels much lower. On the one hand, if carbon dioxide levels rise, it is likely that the Earth will suffer from a greenhouse effect like this. On the other hand, if the percentage of carbon dioxide became even slightly lower, then the reduction in the greenhouse effect would lead to a sharp cooling. Thus, the current level of carbon dioxide contributes to the ideal range comfortable temperatures from -88 °C to 58 °C.

When observing the Earth from space, the first thing that catches your eye is oceans of liquid water. In terms of surface area, oceans cover approximately 70% of the Earth, which is one of the most unique properties of our planet.

Like the Earth's atmosphere, the presence of liquid water is a necessary criterion for supporting life. Scientists believe that life on Earth first appeared 3.8 billion years ago in the ocean, and the ability to move on land appeared in living creatures much later.

Planetologists explain the presence of oceans on Earth for two reasons. The first of these is the Earth itself. There is an assumption that during the formation of the Earth, the planet's atmosphere was able to capture large volumes of water vapor. Over time, the planet's geological mechanisms, primarily its volcanic activity, released this water vapor into the atmosphere, after which in the atmosphere, this vapor condensed and fell to the surface of the planet in the form of liquid water. Another version suggests that the source of water was comets that fell to the surface of the Earth in the past, ice which predominated in their composition and formed the reservoirs that exist on Earth.

Ground surface

Despite the fact that most of the Earth's surface is located under its oceans, the "dry" surface has many distinctive features. When comparing the Earth to other solid bodies in the solar system, its surface is strikingly different because it does not have craters. According to planetary scientists, this does not mean that the Earth has escaped numerous impacts from small cosmic bodies, but rather indicates that evidence of such impacts has been erased. There may be many geological processes responsible for this, but scientists identify the two most important - weathering and erosion. It is believed that in many ways it was the dual impact of these factors that influenced the erasure of traces of craters from the face of the Earth.

So weathering breaks surface structures into smaller pieces, not to mention chemical and physical methods of atmospheric exposure. An example of chemical weathering is acid rain. An example of physical weathering is the abrasion of river beds caused by rocks contained in flowing water. The second mechanism, erosion, is essentially the effect on the relief of the movement of particles of water, ice, wind or earth. Thus, under the influence of weathering and erosion, the impact craters on our planet were “erased”, due to which some relief features were formed.

Scientists also identify two geological mechanisms that, in their opinion, helped shape the Earth's surface. The first such mechanism is volcanic activity - the process of release of magma (molten rock) from the interior of the Earth through breaks in its crust. Perhaps it was due to volcanic activity that the earth's crust was changed and islands were formed (the Hawaiian Islands are a good example). The second mechanism determines mountain building or the formation of mountains as a result of compression of tectonic plates.

Structure of planet earth

Like other terrestrial planets, the Earth consists of three components: the core, mantle and crust. Science now believes that the core of our planet consists of two separate layers: an inner core of solid nickel and iron and an outer core of molten nickel and iron. At the same time, the mantle is a very dense and almost completely solid silicate rock - its thickness is approximately 2850 km. The bark also consists of silicate rocks and varies in thickness. While continental crust ranges from 30 to 40 kilometers in thickness, oceanic crust much thinner - only from 6 to 11 km.

Another distinctive feature of Earth relative to other terrestrial planets is that its crust is divided into cold, rigid plates that rest on a hotter mantle below. In addition, these plates are in constant motion. Along their boundaries, as a rule, two processes occur simultaneously, known as subduction and spreading. During subduction, two plates come into contact producing earthquakes and one plate rides on the other. The second process is separation, where two plates move away from each other.

Earth's orbit and rotation

It takes the Earth approximately 365 days to complete its orbit around the Sun. The length of our year is related largely to the average orbital distance of the Earth, which is 1.50 x 10 to the power of 8 km. At this orbital distance, it takes on average about eight minutes and twenty seconds for sunlight to reach the Earth's surface.

At an orbital eccentricity of .0167, the Earth's orbit is one of the most circular in the entire solar system. This means that the difference between Earth's perihelion and aphelion is relatively small. As a result of such a small difference, the intensity of sunlight on Earth remains virtually unchanged all year round. However, the position of the Earth in its orbit determines one season or another.

The Earth's axial tilt is approximately 23.45°. In this case, the Earth takes twenty-four hours to complete one rotation around its axis. This is the fastest rotation among the terrestrial planets, but slightly slower than all the gas planets.

In the past, the Earth was considered the center of the Universe. For 2000 years, ancient astronomers believed that the Earth was static and that other celestial bodies traveled in circular orbits around it. They came to this conclusion by observing the obvious movement of the Sun and planets when observed from Earth. In 1543, Copernicus published his heliocentric model of the solar system, which places the Sun at the center of our solar system.

Earth is the only planet in the system that was not named after mythological gods or goddesses (the other seven planets in the solar system were named after Roman gods or goddesses). This refers to the five planets visible to the naked eye: Mercury, Venus, Mars, Jupiter and Saturn. The same approach with the names of the ancient Roman gods was used after the discovery of Uranus and Neptune. The word “Earth” itself comes from the old English word “ertha” meaning soil.

Earth is the densest planet in the solar system. The density of the Earth differs in each layer of the planet (the core, for example, is denser than the crust). The average density of the planet is about 5.52 grams per cubic centimeter.

The gravitational interaction between the Earth causes tides on Earth. It is believed that the Moon is blocked by the Earth's tidal forces, so its rotation period coincides with the Earth's and it always faces our planet with the same side.

BASIC DATA ABOUT PLANET EARTH

Planet Earth formed about 4.5 billion years ago.

The Earth is the third planet from the Sun.

Earth is the fifth largest planet in the world and the largest in diameter, mass and density among the terrestrial planets.

Earth's surface area: 510,072,000 km2

Earth mass: 5.9726 1024 kg

The length of the Earth's equator is 40,075 km.

The density of the Earth is higher than any other planet (5.515 g/cm3).

The distance from the Earth to the Sun is almost 150 million km.

It takes planet Earth about 23 hours, 56 minutes and 4.091 seconds to turn around its axis. Recently, the day has shortened by hundredths of a second, indicating that angular velocity the planet has grown. The factors causing this increase have not been established.

The Earth's rotation speed is 107,826 km/h.

The Earth's rotation axis is inclined at an angle of 23.44° relative to the ecliptic plane. It is because of this tilt that we have a change of seasons on planet Earth: summer, winter, spring and autumn.

The Earth is not a perfect sphere; due to the force of rotation, the Earth is actually convex at the equator.

The Earth's core contains hot magma. Not a single drilling rig will be able to reach the core of our planet for at least the next few hundred years.

Our planet's molten iron core creates the Earth's magnetic field. For continuous work magnetic field The Earth is influenced by two factors: its rotation and the impact of the core, the molten mass of which includes nickel and iron.

SATELLITES

Our planet has one natural satellite - .

The fate of the Moon has not yet been clarified. It is not known exactly how it was formed.

The ebb and flow of tides on Earth occur due to the activity of the Moon.

Earth has 2 additional asteroids. They are called 3753 Cruithne and 2002 AA29.

All the planets of the Solar System can be placed between the Earth and the Moon.

PRESENCE OF LIFE

Earth is the only planet where complex life forms exist. It has the necessary amount of water and other conditions that are extremely important for the existence of any form of life.

Throughout the history of the Earth, about 108 billion people have lived on it. Seven billion live here now. And you are one of them.

Only on Earth can we observe three states of water (solid, gaseous, liquid).

ATMOSPHERE

The Earth's atmosphere reaches up to 10,000 kilometers.

Thanks to the Earth's atmosphere, which consists of oxygen, nitrogen and other gases, we are not constantly exposed to falling and radioactive radiation from the sun.

In 2006, an ozone hole was discovered over Antarctica, which is the largest hole previously discovered.

Every year, about 30,000 tons of interplanetary dust reach the Earth's surface.

CONTINENTS AND ISLANDS

Currently, planet Earth has 6 continents.

List of continents of our planet: Eurasia, North America, South America, .

It is extremely difficult to calculate the exact number of islands on our land, because some islands appear, while others, on the contrary, disappear. There is an approximate figure - about 500,000, but this is only a hypothesis, perhaps there are a little more, and perhaps a little less. But you can name, for example, the 4 largest islands on Earth and these are: New Guinea, borneo island and Madagascar.

Antarctica contains 2/3 of reserves fresh water planets.

In the distant future, Africa will “stumble” into Europe, resulting in the formation of a giant Mountain chain.

The plates of the Earth's crust move at a rate of several inches per year, which is approximately equal to the length of a human fingernail growing in a year. On this basis, it can be argued that in 250 million years a new supercontinent will appear on Earth.

The Himalayas are a pattern of tectonic plates moving towards each other.

90% earth ice stored on one single continent - Antarctica. 2/3 of the planet’s freshwater reserves are “hidden” there.

Over 500 thousand earthquakes occur on our planet every year! But only 20% of them can be felt by people.

OCEANS

About 70% of the Earth's surface is occupied by oceans.

All oceans on earth are connected to each other, so we can assume that there is one World giant ocean, consisting of four or five parts.

The existence of four oceans on earth is officially recognized: the Pacific Ocean, the Atlantic Ocean, Indian Ocean and the fourth - Arctic.

At the beginning of the 21st century, the International Hydrographic Organization adopted a division into five parts (adds South ocean), however at the moment this document still does not have legal force.

Most big ocean on Earth - the Pacific Ocean. Its area is so large that it could easily fit all the continents.

Man has not yet explored 95 percent of the world's oceans.

The longest mountain range on Earth is not on land, but in the oceans. It almost completely encircles the planet.

THE BEST

The most high point on Earth - rising above the Earth's surface by almost 9 kilometers (8848 meters). It is located in the Himalayas.

The deepest place on Earth is considered to be located in Pacific Ocean. It is located 10911 meters below sea level.

The lowest temperature recorded on the Earth's surface is -89.2 degrees Celsius. It was registered on July 21, 1983 at Vostok station in Antarctica.

The most heat on the surface of the Earth +56.7 Celsius on July 10, 1913 in Death Valley, USA.

The driest hot place on Earth is not the Sahara, but the Atacama Desert. Rain has never been observed in its central part.

A FEW MORE FACTS

According to one popular hypothesis, the Earth once shared its orbit with another planet, which scientists called Theia. Many billions of years ago, these planets collided, and as a result of the greatest catastrophe in its history, the Earth acquired additional mass and received its own satellite.

Earth is the only planet whose name did not come to us from the Roman or Greek mythology. It comes from the 8th century Anglo-Saxon word "Erda", meaning "ground" or "soil".

Unlike other planets, the word Earth has its own name in every nation.

One of the most beautiful natural phenomena on our planet arises due to the interaction of charged particles coming from the Sun with the Earth’s magnetic field.

Contrary to popular belief, it is not visible from. However, air pollution in China can be seen from space. In addition, you can see from space.

> Planet Earth

Everything about the planet Earth for children: how it appeared and was formed, interesting facts, what the structure is made of in photos and drawings, the rotation of the Earth, the Moon and life.

Start a story about Earth for the little ones It’s possible because we live on the third planet from the Sun. Parents or teachers At school should be explain to the children that they were very lucky. After all, the Earth is so far the only known planet in the solar system that contains an atmosphere with oxygen, liquid oceans on the surface and life.

If we consider by size, then we occupy fifth place (less than , and , but greater than and ).

The diameter of planet Earth is 13,000 km. It is circular in shape because gravity pulls in matter. Although this is not a perfect circle, because rotation causes the planet to compress at the poles and expand at the equator.

Water occupies approximately 71% (most of it is oceans). 1/5 of the atmosphere consists of oxygen, which is produced by plants. While scientists have been studying the planet for centuries, spacecraft have made it possible to look at it from space. Below, schoolchildren and children of all ages will be able to consider interesting facts about the Earth and receive a full description of the third planet from the Sun with photos and pictures. But it should be recalled that the Earth has a class, or rather a planetary type - a rocky body (there are also ice and gas giants that differ in characteristics).

Characteristics of the Earth's orbit - explanation for children

To give full explanation for children, parents must reveal the concept of an axis. This is an imaginary line running through the center from the North to the South Pole. It takes 23.934 hours to complete one revolution, and 365.26 days (Earth year) to orbit around the Sun.

Children should know that the earth's axis is tilted relative to the plane of the ecliptic (the imaginary surface of the earth's orbit around the sun). Because of this, the northern and southern hemispheres sometimes rotate and face away from the Sun. This leads to a change in seasons (the amount of light and heat received changes).

The Earth's orbit is not a perfect circle, but an oval ellipse (this is common to all planets). It approaches the Sun in early January and moves away in July (although this has less effect on heating and cooling than the tilt of the Earth's axis). Should explain to the children the value of having a planet in the habitable zone. This is the distance that allows the temperature to maintain water in a liquid state.

Earth's orbit and rotation - explanation for children

• Average distance from the Sun: 149,598,262 km.
• Perihelion (closest distance to the Sun): 147,098,291 km.
• Aphelion (farthest distance from the Sun): 152,098,233 km.
• Duration sunny day(one axial rotation): 23.934 hours.
• Length of year (one round the Sun): 365.26 days.
• Equatorial inclination to orbit: 23.4393 degrees.

Formation and evolution of the Earth - explanation for children

Explanation for children will remain incomplete if description of the Earth will bypass the background. Researchers believe that the Earth formed along with the Sun and other planets 4.6 billion years ago. Then it reunited with a huge cloud of gas and dust - the solar nebula. Gravity gradually destroyed it, giving more speed and disk shape. Most of the material was drawn to the center and began to form.

Other particles collided and combined to form larger bodies. The solar wind was so powerful that it managed to dislodge lighter elements (hydrogen and helium) from the most distant worlds. This is why the Earth and other planets became rocky.

In early history, planet Earth may seem like a lifeless piece of rock to children. Radioactive materials and pressure rising from the depths provided enough heat to melt the interior. This caused some chemicals to splash out to form water, while others became atmospheric gases. According to recent data, the crust and oceans could have appeared 200 million years after the formation of the planet.

Children should know that earthly history They are divided into 4 eons: Hadean, Archean, Proterozoic and Phanerozoic. The first three took almost 4 billion years and are collectively called the Precambrian. Evidence of life was discovered in the Archean about 3.8 billion years ago. But life was not rich until the Phanerozoic.

The Phanerozoic period is divided into 3 eras: Paleozoic, Mesozoic and Cenozoic. The first demonstrated the emergence of many varieties of animals and plants in the seas and on land. The Mesozoic provided dinosaurs, but the Cenozoic is literally our era (mammals).

Most fossils from the Paleozoic are invertebrate animals (corals, trilobites and mollusks). Fish fossils have been dated back to 450 million years ago, and amphibians to 380 million years old. Vast forests, swamps and early reptiles inhabited the Earth 300 million years ago.

The Mesozoic was the period in which dinosaurs lived. Although mammal fossils were also 200 million years old. During this period, power was seized flowering plant(and continue to hold it today).

The Cenozoic era began about 65 million years ago, when the dinosaurs became extinct (scientists attribute this to cosmic influences). Mammals managed to survive, and they became the main creatures on the planet.

Composition and structure of the Earth - explanation for children

Atmosphere

Composition: 78% nitrogen and 21% oxygen with small admixtures of water, carbon dioxide, argon and other gases. Nowhere else in the solar system will you find an atmosphere filled with free oxygen. But this is exactly what turned out to be important for our lives.

The earth is surrounded by air, becoming thin as it moves away from the surface. At an altitude of 160 km, it is so thin that satellites have to overcome only minor resistance. But traces of the atmosphere are still found at an altitude of 600 km.

Most bottom layer atmosphere - troposphere. She does not stop her movement and is responsible for weather. Sunlight heats the atmosphere, creating a warm air current. It expands and cools as pressure decreases. Children must understand that cold air becomes denser, so it sinks down to warm the lower layers.

The stratosphere is located at an altitude of 48 km. It's motionless ozone layer, created by ultraviolet light causing a trio of oxygen atoms to form the ozone molecule. For the little ones It will be interesting to know that it is ozone that protects us from most of the dangerous ultraviolet radiation.

Carbon dioxide, water vapor and other gases trap heat and warm the Earth. If it were not for this “greenhouse effect,” the surface would be too cold and would not allow life to develop. Although the wrong greenhouse could turn us into a hellishly hot version of Venus.

Satellites in Earth orbit have shown that upper atmosphere expands during the day and decreases at night due to heating and cooling processes.

A magnetic field

The Earth's magnetic field is created by currents emanating from the outer layer of the earth's core. Magnetic poles always moving. The magnetic north pole accelerates movement up to 40 km per year. In a few decades he will leave North America and will reach Siberia.

NASA believes the magnetic field changes in other directions as well. Globally it has weakened by 10%, measured since the 19th century. Although these transformations are insignificant if you delve into the distant past. Sometimes the field was completely turned over, changing the north and south pole in some places.

When particles charged by the Sun find themselves in a magnetic field, they break up into air molecules above the poles and create the northern and southern lights.

Chemical composition

The most common element in the earth's crust is oxygen (47%). Next come silicon (27%), aluminum (8%), iron (5%), calcium (4%), and 2% each of potassium, sodium and magnesium.

The Earth's core consists mainly of nickel, iron and lighter elements (sulfur and oxygen). The mantle is made of silicate rocks rich in iron and magnesium (a combination of silicon and oxygen called silica, and materials containing it are called silicate).

Internal structure

Schoolchildren and children of all ages should remember that the Earth's core is 7,100 km wide (a little more than half the Earth's diameter and roughly the size of Mars). The outermost layers (2250 km) are liquid, but the inner one is a solid body and reaches 4/5 the size of the Moon (2600 km in diameter).

Above the core is a mantle 2900 km thick. Children could hear At school that it is not completely rigid, but can flow very slowly. The Earth's crust floats across it, causing the continents to shift almost imperceptibly. True, people realize this in the form of earthquakes, erupting volcanoes and the formation of mountain ranges.

There are two types of earth's crust. The landmass of the continents consists mostly of granite and other light silicate minerals. The ocean floors are dark and dense volcanic rock - basalt. The continental crust is up to 40 km thick, although it may vary depending on the specific area. The oceanic one grows to only 8 km. Water fills low areas of basalt and forms the world's oceans. The Earth has a lot of water, so it completely fills the ocean basins. The rest reaches the edges of the continents - the continental plume.

The closer to the core, the warmer it is. At the very bottom of the continental crust, temperatures reach 1000 °C and increase by 1 °C with every kilometer down. Geologists suggest that the outer core is heated to 3700-4300 °C, and the inner core - 7000 °C. This is even hotter than the surface of the Sun. Only enormous pressure allows its structure to be preserved.

Recent exoplanet studies (such as NASA's Kepler mission) suggest that Earth-like planets are found throughout our galaxy. Almost a quarter of observed solar stars may have potential habitable Earths.

Earth's Moon - explanation for children

Children should not forget that the Earth has a faithful satellite - the Moon. It reaches a width of 3474 km (about a quarter of the Earth's diameter). Our planet has only one satellite, although Venus and Mercury do not have them at all, and some have two or more.

The moon was formed after a giant object crashed into the Earth. The torn off debris became the constituent material of the Moon. Scientists believe the object was roughly the size of Mars.

It is currently known that Earth is the only planet in the Universe inhabited by life. Numbers several million known species from the deepest ocean floor to the highest levels of the atmosphere. But researchers say not everything has been discovered yet (estimated at 5-100 million, of which only about 2 million have been found).

Scientists suspect that there are other habitable planets. Among them, Saturn's moon Titan or Jupiter's Europa are being considered. While researchers are still understanding the processes of evolution, it seems that Mars has every chance of having organisms. Some people think that it was from Martian meteorites that fell to Earth that our life originated.

It is important to remind children that our planet is considered the most studied, because the exploration of the Earth has been carried out from primitive tribes to today. A bunch of interesting sciences offer characteristics of the planet from all sides. Geography of the Earth reveals countries, geology studies the composition and movement of plates, and biology examines living organisms. To make it more interesting for your child to explore the Earth, use printed or Google maps, as well as our online telescopes. Do not forget that planet Earth is a unique system and so far the only world with life. Therefore, it must not only be studied comprehensively, but also protected.

Earth- the third planet of the solar system. Find out the description of the planet, mass, orbit, size, interesting facts, distance to the Sun, composition, life on Earth.

Of course we love our planet. And not only because it native home, but also because this is a unique place in the Solar System and the Universe, because so far we only know life on Earth. Lives in the inner part of the system and occupies a place between Venus and Mars.

Planet Earth also called the Blue Planet, Gaia, World and Terra, which reflects its role for each people in historical terms. We know that our planet is rich in many various forms life, but how exactly did she manage to become like this? First, consider some interesting facts about Earth.

Interesting facts about planet Earth

Rotation gradually slows down

• For earthlings, the entire process of slowing down the rotation of the axis occurs almost imperceptibly - 17 milliseconds per 100 years. But the nature of the speed is not uniform. Because of this, the length of the day increases. In 140 million years, a day will cover 25 hours.

Believed that the Earth was the center of the Universe

• Ancient scientists could observe celestial objects from the position of our planet, so it seemed that all objects in the sky were moving relative to us, and we remained at one point. As a result, Copernicus declared that the Sun is at the center of everything ( heliocentric system world), although now we know that this does not correspond to reality, if we take the scale of the Universe.

Endowed with a powerful magnetic field

• The Earth's magnetic field is created by the nickel-iron planetary core, which rotates rapidly. The field is important because it protects us from the influence of the solar wind.

Has one satellite

• If you look at the percentage, the Moon protrudes largest satellite in system. But in reality it is in 5th position in size.

The only planet not named after a deity

• Ancient scientists named all 7 planets in honor of the gods, and modern scientists followed the tradition when discovering Uranus and Neptune.

First in density

• Everything is based on the composition and specific part of the planet. So the core is represented by metal and bypasses the crust in density. The average density of the earth is 5.52 grams per cm 3.

Size, mass, orbit of planet Earth

With a radius of 6371 km and a mass of 5.97 x 10 24 kg, the Earth ranks 5th in size and massiveness. It is the largest terrestrial planet, but it is smaller in size than the gas and ice giants. However, in terms of density (5.514 g/cm3) it ranks first in the Solar System.

There is a slight eccentricity in the orbit (0.0167). The distance from the star at perihelion is 0.983 AU, and at aphelion – 1.015 AU.

One passage around the Sun takes 365.24 days. We know that due to existence leap year, we add a day every 4 passes. We are used to thinking that a day lasts 24 hours, but in reality this time takes 23 hours 56 minutes and 4 seconds.

If you observe the rotation of the axis from the poles, you can see that it occurs counterclockwise. The axis is inclined at 23.439281° from the perpendicular to the orbital plane. This affects the amount of light and heat.

If North Pole turned towards the Sun, then summer sets in in the northern hemisphere, and winter in the southern hemisphere. At a certain time, the Sun does not rise at all over the Arctic Circle, and then night and winter last there for 6 months.

Composition and surface of planet Earth

The shape of planet Earth is like a spheroid, flattened at the poles and with a convexity at the equatorial line (diameter - 43 km). This happens due to rotation.

The structure of the Earth is represented by layers, each of which has its own chemical composition. It differs from other planets in that our core has a clear distribution between the solid inner (radius - 1220 km) and the liquid outer (3400 km).

Next comes the mantle and crust. The first goes deeper to 2890 km (the most dense layer). It is represented by silicate rocks with iron and magnesium. The crust is divided into lithosphere (tectonic plates) and asthenosphere (low viscosity). You can carefully examine the structure of the Earth in the diagram.

The lithosphere breaks down into solid tectonic plates. These are rigid blocks that move relative to each other. There are points of connection and break. It is their contact that leads to earthquakes, volcanic activity, the creation of mountains and ocean trenches.

There are 7 main plates: Pacific, North American, Eurasian, African, Antarctic, Indo-Australian and South American.

Our planet is notable for the fact that approximately 70.8% of its surface is covered with water. The bottom map of the Earth shows tectonic plates.

The earth's landscape is different everywhere. The submerged surface resembles mountains and has underwater volcanoes, oceanic trenches, canyons, plains and even oceanic plateaus.

During the development of the planet, the surface was constantly changing. Here it is worth considering the movement of tectonic plates, as well as erosion. It also affects the transformation of glaciers, the creation of coral reefs, meteorite impacts, etc.

Continental crust is represented by three varieties: magnesium rocks, sedimentary and metamorphic. The first is divided into granite, andesite and basalt. Sedimentary makes up 75% and is created by burying accumulated sediment. The latter is formed during the icing of sedimentary rock.

From the lowest point, the surface height reaches -418 m (at the Dead Sea) and rises to 8848 m (the top of Everest). Average height land above sea level - 840 m. The mass is also divided between the hemispheres and continents.

The outer layer contains soil. This is a certain line between the lithosphere, atmosphere, hydrosphere and biosphere. Approximately 40% of the surface is used for agricultural purposes.

Atmosphere and temperature of planet Earth

There are 5 layers of the earth's atmosphere: troposphere, stratosphere, mesosphere, thermosphere and exosphere. The higher you rise, the less air, pressure and density feel.

The troposphere is located closest to the surface (0-12 km). Contains 80% of the mass of the atmosphere, with 50% located within the first 5.6 km. It consists of nitrogen (78%) and oxygen (21%) with admixtures of water vapor, carbon dioxide and other gaseous molecules.

In the interval of 12-50 km we see the stratosphere. Separated from the first tropopause - a line with a relatively warm air. This is where the ozone layer is located. The temperature rises as the layer absorbs ultraviolet light. The atmospheric layers of the Earth are shown in the figure.

This is a stable layer and is practically free from turbulence, clouds and other weather formations.

At an altitude of 50-80 km there is the mesosphere. This is the coldest place (-85°C). It is located near the mesopause, extending from 80 km to the thermopause (500-1000 km). The ionosphere lives within the range of 80-550 km. Here the temperature increases with altitude. In the photo of the Earth you can admire the northern lights.

The layer is devoid of clouds and water vapor. But it is here that auroras are formed and the International space station(320-380 km).

The outermost sphere is the exosphere. This is a transition layer to outer space, devoid of an atmosphere. Represented by hydrogen, helium and heavier molecules with low density. However, the atoms are so scattered that the layer does not behave like a gas, and particles are constantly being removed into space. Most of the satellites live here.

This mark is influenced by many factors. The Earth makes an axial revolution every 24 hours, which means one side always experiences night and lower temperatures. In addition, the axis is tilted, so the northern and southern hemispheres alternately move away and move closer.

All this creates seasonality. Not every earthly part experiences sharp drops and rises in temperatures. For example, the amount of light entering the equatorial line remains virtually unchanged.

If we take the average, we get 14°C. But the maximum was 70.7°C (Lut Desert), and the minimum of -89.2°C was reached at the Soviet Vostok station on the Antarctic plateau in July 1983.

Moon and asteroids of the Earth

The planet has only one satellite, which affects not only the physical changes of the planet (for example, the ebb and flow of tides), but is also reflected in history and culture. To be precise, the Moon is the only celestial body on which a person has walked. This happened on July 20, 1969 and the right to take the first step went to Neil Armstrong. Overall, 13 astronauts landed on the satellite.

The Moon appeared 4.5 billion years ago due to the collision of the Earth and a Martian-sized object (Theia). We can be proud of our satellite, because it is one of the largest moons in the system, and also ranks second in density (after Io). It is in gravitational locking (one side always faces the Earth).

The diameter covers 3474.8 km (1/4 of the Earth), and the mass is 7.3477 x 10 22 kg. The average density is 3.3464 g/cm3. In terms of gravity it reaches only 17% of the Earth's. The moon influences the earth's tides, as well as the activity of all living organisms.

Don't forget that there are lunar and solar eclipses. The first happens when the Moon falls into the Earth's shadow, and the second happens when a satellite passes between us and the Sun. The satellite's atmosphere is weak, causing temperatures to fluctuate greatly (from -153°C to 107°C).

Helium, neon and argon can be found in the atmosphere. The first two are created by the solar wind, and argon is due to the radioactive decay of potassium. There is also evidence of frozen water in craters. The surface is divided into Various types. There is Maria - flat plains that ancient astronomers mistook for seas. Terras are lands, like highlands. Even mountainous areas and craters can be seen.

The Earth has five asteroids. Satellite 2010 TK7 resides at L4, and asteroid 2006 RH120 approaches the Earth-Moon system every 20 years. If we talk about artificial satellites, there are 1265 of them, as well as 300,000 pieces of debris.

Formation and evolution of planet Earth

In the 18th century, humanity came to the conclusion that our terrestrial planet, like the entire solar system, emerged from a nebulous cloud. That is, 4.6 billion years ago, our system resembled a circumstellar disk, represented by gas, ice and dust. Then most of it approached the center and, under pressure, transformed into the Sun. The remaining particles created the planets we know.

The primordial Earth appeared 4.54 billion years ago. From the very beginning, it was molten due to volcanoes and frequent collisions with other objects. But 4-2.5 billion years ago, solid crust and tectonic plates appeared. Degassing and volcanoes created the first atmosphere, and ice arriving on comets formed the oceans.

The surface layer did not remain frozen, so the continents converged and moved apart. About 750 million years ago, the very first supercontinent began to break apart. Pannotia was created 600-540 million years ago, and the last one (Pangea) collapsed 180 million years ago.

The modern picture was created 40 million years ago and took hold 2.58 million years ago. The last one is going on now glacial period, which began 10,000 years ago.

It is believed that the first hints of life on Earth appeared 4 billion years ago (Archean eon). Because of chemical reactions self-replicating molecules appeared. Photosynthesis created molecular oxygen, which, together with ultraviolet rays, formed the first ozone layer.

Then various multicellular organisms began to appear. Microbial life arose 3.7-3.48 billion years ago. 750-580 million years ago, most of the planet was covered with glaciers. Active reproduction of organisms began during the Cambrian explosion.

Since that time (535 million years ago), history includes 5 major extinction events. The last one (the death of dinosaurs from a meteorite) occurred 66 million years ago.

They were replaced by new species. The African ape-like animal stood on its hind legs and freed its forelimbs. This stimulated the brain to use different tools. Then we know about the development of agricultural crops, socialization and other mechanisms that led us to modern man.

Reasons for the habitability of planet Earth

If a planet meets a number of conditions, then it is considered potentially habitable. Now the Earth is the only lucky one with developed life forms. What is needed? Let's start with the main criterion - liquid water. In addition, the main star must provide enough light and heat to maintain the atmosphere. Important factor– location in the habitable zone (distance of the Earth from the Sun).

We should understand how lucky we are. After all, Venus is similar in size, but due to its close location to the Sun, it is a hellishly hot place with acid rain. And Mars, which lives behind us, is too cold and has a weak atmosphere.

Planet Earth Research

The first attempts to explain the origin of the Earth were based on religion and myths. Often the planet became a deity, namely a mother. Therefore, in many cultures, the history of everything begins with the mother and the birth of our planet.

There are also a lot of interesting things in the form. In ancient times, the planet was considered flat, but different cultures added their own characteristics. For example, in Mesopotamia, a flat disk floated in the middle of the ocean. The Mayans had 4 jaguars that held up the heavens. For the Chinese it was generally a cube.

Already in the 6th century BC. e. scientists sewed to round shape. Surprisingly, in the 3rd century BC. e. Eratosthenes even managed to calculate the circle with an error of 5-15%. The spherical shape became established with the advent of the Roman Empire. About changes in earth's surface Aristotle also spoke. He believed that it happens too slowly, so a person is not able to catch it. This is where attempts to understand the age of the planet arise.

Scientists are actively studying geology. The first catalog of minerals was created by Pliny the Elder in the 1st century AD. In 11th century Persia, explorers studied Indian geology. The theory of geomorphology was created by the Chinese naturalist Shen Guo. He identified marine fossils located far from the water.

In the 16th century, understanding and exploration of the Earth expanded. We should thank the heliocentric model of Copernicus, which proved that the Earth is not the universal center (previously they used the geocentric system). And Galileo Galilei for his telescope.

In the 17th century, geology became firmly established among other sciences. They say that the term was coined by Ulysses Aldvandi or Mikkel Eschholt. The fossils discovered at that time caused serious controversy in the age of the earth. All the religious people insisted on 6000 years (as the Bible said).

This debate ended in 1785 when James Hutton declared that the Earth was much older. It was based on the erosion of rocks and the calculation of the time required for this. In the 18th century, scientists were divided into 2 camps. The former believed that the rocks were deposited by floods, while the latter complained about the fiery conditions. Hutton stood in firing position.

First geological maps The lands appeared in the 19th century. The main work is “Principles of Geology”, published in 1830 by Charles Lyell. In the 20th century, age calculations became much easier thanks to radiometric dating (2 billion years). However, the study of tectonic plates has already led to the modern mark of 4.5 billion years.

The future of planet Earth

Our life depends on the behavior of the Sun. However, each star has its own evolutionary path. It is expected that in 3.5 billion years it will increase in volume by 40%. This will increase the flow of radiation, and the oceans may simply evaporate. Then the plants will die, and in a billion years all living things will disappear, and the constant average temperature will be fixed at around 70°C.

In 5 billion years, the Sun will transform into a red giant and shift our orbit by 1.7 AU.

If you look at the entire history of the earth, then humanity is just a fleeting blip. However, the Earth remains the most important planet, home and unique place. One can only hope that we will have time to populate other planets outside our system before critical period solar development. Below you can explore a map of the Earth's surface. In addition, on our website there are many beautiful photos of the planet and places on Earth from space to high resolution. Using online telescopes from the ISS and satellites, you can observe the planet for free in real time.

Click on the image to enlarge it

What could be inside our home planet? Simply put, what is the Earth made of, what is its internal structure? These questions have long troubled scientists. But it turned out that clarifying this issue is not so simple. Even with the help of ultra-modern technologies, a person can only go inside to a distance of fifteen kilometers, and this, of course, is not enough to understand and substantiate everything. Therefore, even today, research on the topic “what the Earth is made of” is carried out mainly using indirect data and assumptions and hypotheses. But in this too, scientists have already achieved certain results.

How to study the planet

Even in ancient times, individual representatives of humanity sought to know what the Earth is made of. People also studied sections of rocks exposed by nature itself and available for viewing. These are, first of all, cliffs, mountain slopes, steep shores of seas and rivers. You can understand a lot from these natural sections, because they consist of rocks that were here millions of years ago. And today scientists are drilling wells in some places on land. Of these, the deepest is 15 km. Also, the study is carried out with the help of mines dug for the extraction of minerals: coal and ore, for example. Rock samples are also extracted from them that can tell people about what the Earth is made of.

Indirect data

But this is what concerns experiential and visual knowledge about the structure of the planet. But with the help of the science of seismology (the study of earthquakes) and geophysics, scientists penetrate into the depths without contact, analyzing seismic waves and their propagation. This data tells us about the properties of substances located deep underground. The structure of the planet is being studied and with the help artificial satellites that are in orbit.

What is planet Earth made of?

The internal structure of the planet is heterogeneous. Today, research scientists have established that the inside consists of several parts. In the middle is the core. Next is the mantle, which is huge and makes up about five-sixths of the entire outer crust is represented by a thin layer covering the sphere. These three components, in turn, are also not entirely homogeneous and have structural features.

Core

What does the earth's core consist of? Scientists put forward several versions of the composition and origin of the central part of the planet. The most popular: the core is an iron-nickel melt. The core is divided into several parts: the inner one is solid, the outer one is liquid. It is very heavy: it makes up more than a third total mass planet (for comparison, its volume is only 15%). According to scientists, it formed gradually over time, and iron and nickel were released from silicates. Currently (in 2015), scientists from Oxford have proposed a version according to which the core consists of radioactive uranium. This, by the way, explains both the increased heat transfer of the planet and the existence of the magnetic field to this day. In any case, information about what the Earth's core consists of can only be obtained hypothetically, since prototypes modern science not available.

Mantle

What it consists of It should immediately be noted that, as in the case of the core, scientists have not yet had a chance to get to it. Therefore, the study is also carried out with the help of theories and hypotheses. IN last years However, Japanese researchers are drilling at the bottom of the ocean, where there will be “only” 3000 km to the mantle. But the results have not yet been announced. And the mantle, according to scientists, consists of silicates - rocks saturated with iron and magnesium. They are in a molten liquid state (temperature reaches 2500 degrees). And, oddly enough, the mantle also contains water. There's a lot of it there (if you throw it all out internal water to the surface, the level of the world's oceans would rise by 800 meters).

Earth's crust

It occupies only a little more than a percent of the planet by volume and a little less by mass. But, despite its light weight, the earth’s crust is very important for humanity, because it is on it that all life on Earth lives.

Spheres of the Earth

It is known that the age of our planet is approximately 4.5 billion years (scientists have found this out using radiometric data). When studying the Earth, several inherent shells, called geospheres, were identified. They differ both in their chemical composition and in physical properties. The hydrosphere includes all the water available on the planet in its various states (liquid, solid, gaseous). The lithosphere is a rocky shell that tightly encircles the Earth (from 50 to 200 km thick). The biosphere is all living things on the planet, including bacteria, plants, and people. The atmosphere (from the ancient Greek “atmos”, which means steam) is airy without which the existence of life would be impossible.

What does the Earth's atmosphere consist of?

The inner part of this shell, which is essential for life, is adjacent to and is a gaseous substance. And the external one borders on the near-Earth space. It determines the weather on the planet, and is also not homogeneous in its composition. What does the Earth's atmosphere consist of? Modern scientists can accurately determine its components. Nitrogen percentage - more than 75%. Oxygen - 23%. Argon - just over 1 percent. Quite a bit: carbon dioxide, neon, helium, methane, hydrogen, xenon and some other substances. The water content ranges from 0.2% to 2.5% depending on the climate zone. The carbon dioxide content is also variable. Some characteristics of the Earth's modern atmosphere directly depend on human industrial activity.