Features of the earth. Earth is a unique planet

Characteristics of the planet:

Distance from the Sun: 149.6 million km
Planet diameter: 12,765 km
Day on the planet: 23h 56min 4s*
Year on the planet: 365 days 6h 9min 10s*
t° on the surface: global average +12°C (In Antarctica up to -85°C; in the Sahara Desert up to +70°C)
Atmosphere: 77% Nitrogen; 21% oxygen; 1% water vapor and other gases
Satellites: Moon

* period of rotation around its own axis (in Earth days)
**period of orbit around the Sun (in Earth days)

From the very beginning of the development of civilization, people were interested in the origin of the Sun, planets and stars. But the planet that is of most interest is ours. common house, Earth. Ideas about it have changed along with the development of science; the very concept of stars and planets, as we understand it now, was formed only a few centuries ago, which is negligible compared to the very age of the Earth.

Presentation: Planet Earth

The third planet from the Sun, which has become our home, has a satellite - the Moon, and is part of the group of terrestrial planets such as Mercury, Venus and Mars. Giant planets differ significantly from them in physical properties and structure. But even such a tiny planet in comparison with them, like the Earth, has an incredible mass in terms of comprehension - 5.97x1024 kilograms. It revolves around the star in an orbit at an average distance from the Sun of 149.0 million kilometers, rotating around its axis, which causes the change of days and nights. And the ecliptic of the orbit itself characterizes the seasons.

Our planet plays a unique role in the solar system, because Earth is the only planet that has life! The Earth was positioned in an extremely fortunate way. It travels in orbit at a distance of almost 150,000,000 kilometers from the Sun, which means only one thing - It’s warm enough on Earth for water to remain in liquid form. Given hot temperatures, the water would simply evaporate, and in the cold it would turn into ice. Only on Earth is there an atmosphere in which humans and all living organisms can breathe.

The history of the origin of planet Earth

Starting from the Big Bang Theory and based on the study of radioactive elements and their isotopes, scientists have found out the approximate age of the earth's crust - it is about four and a half billion years, and the age of the Sun is about five billion years. Just like the entire galaxy, the Sun was formed as a result of gravitational compression of a cloud of interstellar dust, and after the star, the planets included in the Solar System were formed.

As for the formation of the Earth itself as a planet, its very birth and formation lasted hundreds of millions of years and took place in several phases. During the birth phase, obeying the laws of gravity, a large number of planetesimals and large cosmic bodies fell onto its ever-growing surface, which subsequently made up almost the entire modern mass of the earth. Under the influence of such bombardment, the planet's substance warmed up and then melted. Under the influence of gravity heavy elements, such as ferrum and nickel, created the core, and from lighter compounds formed the earth's mantle, the crust with its continents and oceans lying on its surface, and an atmosphere that was initially very different from the present one.

Internal structure of the Earth

Of the planets of its group, the Earth has the greatest mass and therefore has the greatest internal energy - gravitational and radiogenic, under the influence of which processes in the earth's crust still continue, as can be seen from volcanic and tectonic activity. Although igneous, metamorphic and sedimentary rocks have already formed, forming the outlines of landscapes that are gradually changing under the influence of erosion.

Beneath our planet's atmosphere is a solid surface called the earth's crust. It is divided into huge pieces (slabs) of solid rock, which can move and, when moving, touch and push each other. As a result of this movement, mountains and other features appear earth's surface.

The earth's crust has a thickness of 10 to 50 kilometers. The crust “floats” on the liquid earth’s mantle, the mass of which is 67% of the mass of the entire Earth and extends to a depth of 2890 kilometers!

The mantle is followed by an outer liquid core, which extends further into the depths for another 2,260 kilometers. This layer is also mobile and capable of emitting electric currents, which create the planet’s magnetic field!

At the very center of the Earth is the inner core. It is very hard and contains a lot of iron.

Atmosphere and surface of the Earth

The Earth is the only one of all the planets in the solar system that has oceans - they cover more than seventy percent of its surface. Initially, water in the atmosphere in the form of steam played a big role in the formation of the planet - the greenhouse effect raised the temperature on the surface by those tens of degrees necessary for the existence of water in the liquid phase, and in combination with solar radiation gave rise to photosynthesis of living matter - organic matter.

From space, the atmosphere appears as a blue border around the planet. This thin dome consists of 77% nitrogen, 20% oxygen. The rest is a mixture of various gases. Earth's atmosphere contains much more oxygen than any other planet. Oxygen is vital for animals and plants.

This unique phenomenon can be regarded as a miracle or considered an incredible coincidence of chance. It was the ocean that gave rise to the origin of life on the planet, and, as a consequence, the emergence of homo sapiens. Surprisingly, the oceans still hold many secrets. Developing, humanity continues to explore space. Entering low-Earth orbit has made it possible to gain a new understanding of many of the geoclimatic processes occurring on Earth, the mysteries of which are still to be further studied by more than one generation of people.

Earth's satellite - Moon

Planet Earth has its only satellite - the Moon. The first to describe the properties and characteristics of the Moon was the Italian astronomer Galileo Galilei, he described the mountains, craters and plains on the surface of the Moon, and in 1651 the astronomer Giovanni Riccioli wrote a map of the visible side of the lunar surface. In the 20th century, on February 3, 1966, the Luna-9 lander landed on the Moon for the first time, and a few years later, on July 21, 1969, a person set foot on the surface of the Moon for the first time.

The Moon always faces planet Earth with only one side. On this visible side The moon shows flat "seas", chains of mountains and multiple craters of the most different sizes. The other side, invisible from Earth, has a large cluster of mountains and even more craters on the surface, and the light reflecting from the Moon, thanks to which at night we can see it in a pale lunar color, is weakly reflected rays from the Sun.

Planet Earth and its satellite the Moon are very different in many properties, while the ratio of stable oxygen isotopes of planet Earth and its satellite the Moon is the same. Radiometric studies have shown that the age of both celestial bodies is the same, approximately 4.5 billion years. These data give rise to the assumption of the origin of the Moon and the Earth from one substance, which gives rise to several interesting hypotheses about the origin of the Moon: from its origin from one protoplanetary cloud, the capture of the Moon by the Earth, and to the formation of the Moon from the collision of the Earth with a large object.

The Earth is the object of study for a significant amount of geosciences. Exploring the Earth How celestial body belongs to the field, the structure and composition of the Earth is studied by geology, the state of the atmosphere - meteorology, the totality of manifestations of life on the planet - biology. Geography describes the relief features of the planet's surface - oceans, seas, lakes and waters, continents and islands, mountains and valleys, as well as settlements and societies. education: cities and villages, states, economic regions, etc.

Planetary characteristics

The Earth revolves around the star Sun in an elliptical orbit (very close to circular) with average speed 29,765 m/s at an average distance of 149,600,000 km over a period, which is approximately equal to 365.24 days. The Earth has a satellite, which revolves around the Sun at an average distance of 384,400 km. The inclination of the earth's axis to the ecliptic plane is 66 0 33 "22". The period of revolution of the planet around its axis is 23 hours 56 minutes 4.1 s. Rotation around its axis causes the change of day and night, and the tilt of the axis and revolution around the Sun causes a change of times year.

The shape of the Earth is geoid. The average radius of the Earth is 6371.032 km, equatorial - 6378.16 km, polar - 6356.777 km. Surface area globe 510 million km², volume - 1.083 10 12 km², average density - 5518 kg/m³. The mass of the Earth is 5976.10 21 kg. The earth has a magnetic field and a closely related electric field. The Earth's gravitational field determines its close to spherical shape and the existence of an atmosphere.

According to modern cosmogonic concepts, the Earth was formed approximately 4.7 billion years ago from gaseous matter scattered in the protosolar system. As a result of the differentiation of the Earth's substance, under the influence of its gravitational field, in the conditions of heating the earth's interior, various types arose and developed. chemical composition, state of aggregation and physical properties of the shell - the geosphere: core (in the center), mantle, earth's crust, hydrosphere, atmosphere, magnetosphere. The composition of the Earth is dominated by iron (34.6%), oxygen (29.5%), silicon (15.2%), magnesium (12.7%). The Earth's crust, mantle, and inner core are solid (the outer core is considered liquid). From the surface of the Earth towards the center, pressure, density and temperature increase. The pressure at the center of the planet is 3.6 10 11 Pa, the density is approximately 12.5 10³ kg/m³, and the temperature ranges from 5000 to 6000 °C. The main types of the earth's crust are continental and oceanic; in the transition zone from the continent to the ocean, crust of an intermediate structure is developed.

Shape of the Earth

The figure of the Earth is an idealization that is used to try to describe the shape of the planet. Depending on the purpose of the description, various models of the shape of the Earth are used.

First approximation

The roughest form of description of the figure of the Earth at the first approximation is a sphere. For most problems of general geoscience, this approximation seems sufficient to be used in the description or study of certain geographical processes. In this case, the oblateness of the planet at the poles is rejected as an insignificant remark. The Earth has one axis of rotation and an equatorial plane - a plane of symmetry and a plane of symmetry of meridians, which characteristically distinguishes it from the infinity of sets of symmetry of an ideal sphere. The horizontal structure of the geographic envelope is characterized by a certain zonality and a certain symmetry relative to the equator.

Second approximation

At a closer approach, the figure of the Earth is equated to an ellipsoid of revolution. This model, characterized by a pronounced axis, an equatorial plane of symmetry and meridional planes, is used in geodesy for calculating coordinates, constructing cartographic networks, calculations, etc. The difference between the semi-axes of such an ellipsoid is 21 km, the major axis is 6378.160 km, the minor axis is 6356.777 km, the eccentricity is 1/298.25. The position of the surface can easily be theoretically calculated, but it cannot be determined experimentally in nature.

Third approximation

Since the equatorial section of the Earth is also an ellipse with a difference in the lengths of the semi-axes of 200 m and an eccentricity of 1/30000, the third model is a triaxial ellipsoid. This model is almost never used in geographical studies; it only indicates the complexity internal structure planets.

Fourth approximation

The geoid is an equipotential surface that coincides with the average level of the World Ocean; it is the geometric locus of points in space that have the same gravitational potential. Such a surface has an irregular complex shape, i.e. is not a plane. The level surface at each point is perpendicular to the plumb line. Practical significance and the importance of this model lies in the fact that only with the help of a plumb line, level, level and other geodetic instruments can one trace the position of level surfaces, i.e. in our case, the geoid.

Ocean and land

A general feature of the structure of the earth's surface is its distribution into continents and oceans. Most of the Earth is occupied by the World Ocean (361.1 million km² 70.8%), land is 149.1 million km² (29.2%), and forms six continents (Eurasia, Africa, North America, South America, and Australia) and islands. It rises above sea level by an average of 875 m ( highest height 8848 m - Mount Chomolungma), mountains occupy over 1/3 of the land surface. Deserts cover approximately 20% of the land surface, forests - about 30%, glaciers - over 10%. The height amplitude on the planet reaches 20 km. The average depth of the world's oceans is approximately 3800 m (the greatest depth is 11020 m - the Mariana Trench (trench) in the Pacific Ocean). The volume of water on the planet is 1370 million km³, the average salinity is 35 ‰ (g/l).

Geological structure

Geological structure of the Earth

The inner core is thought to be 2,600 km in diameter and composed of pure iron or nickel, the outer core is 2,250 km thick of molten iron or nickel, and the mantle, about 2,900 km thick, is composed primarily of hard rock, separated from the crust by the Mohorovic surface. The crust and upper mantle form 12 main moving blocks, some of which support continents. Plateaus are constantly moving slowly, this movement is called tectonic drift.

Internal structure and composition of the “solid” Earth. 3. consists of three main geospheres: the earth's crust, mantle and core, which, in turn, is divided into a number of layers. The substance of these geospheres differs in physical properties, condition and mineralogical composition. Depending on the magnitude of the velocities of seismic waves and the nature of their changes with depth, the “solid” Earth is divided into eight seismic layers: A, B, C, D ", D ", E, F and G. In addition, a particularly strong layer is distinguished in the Earth the lithosphere and the next, softened layer - the asthenosphere. Ball A, or the earth's crust, has a variable thickness (in the continental region - 33 km, in the oceanic region - 6 km, on average - 18 km).

The crust thickens under the mountains and almost disappears in the rift valleys of mid-ocean ridges. At the lower boundary of the earth's crust, the Mohorovicic surface, the velocities of seismic waves increase abruptly, which is mainly associated with a change in the material composition with depth, the transition from granites and basalts to ultrabasic rocks of the upper mantle. Layers B, C, D", D" are included in the mantle. Layers E, F and G form the Earth's core with a radius of 3486 km. At the border with the core (Gutenberg surface), the speed of longitudinal waves sharply decreases by 30%, and transverse waves disappear, which means that the outer core (layer E, extends to a depth of 4980 km) liquid Below the transition layer F (4980-5120 km) there is a solid inner core (layer G), in which transverse waves again propagate.

The following chemical elements predominate in the solid crust: oxygen (47.0%), silicon (29.0%), aluminum (8.05%), iron (4.65%), calcium (2.96%), sodium (2.5%), magnesium (1.87%), potassium (2.5%), titanium (0.45%), which add up to 98.98%. The rarest elements: Po (approximately 2.10 -14%), Ra (2.10 -10%), Re (7.10 -8%), Au (4.3 10 -7%), Bi (9 10 -7%) etc.

As a result of magmatic, metamorphic, tectonic and sedimentation processes, the earth's crust is sharply differentiated, complex processes of concentration and dispersion occur in it chemical elements, leading to the formation of various types of rocks.

The upper mantle is believed to be similar in composition to ultramafic rocks, dominated by O (42.5%), Mg (25.9%), Si (19.0%) and Fe (9.85%). In mineral terms, olivine reigns here, with fewer pyroxenes. The lower mantle is considered an analogue of stony meteorites (chondrites). The Earth's core is similar in composition to iron meteorites and contains approximately 80% Fe, 9% Ni, 0.6% Co. Based on the meteorite model, the average composition of the Earth was calculated, which is dominated by Fe (35%), A (30%), Si (15%) and Mg (13%).

Temperature is one of the the most important characteristics of the earth's interior, allowing us to explain the state of matter in various layers and build an overall picture global processes. According to measurements in wells, the temperature in the first kilometers increases with depth with a gradient of 20 °C/km. At a depth of 100 km, where the primary sources of volcanoes are located, the average temperature is slightly lower than the melting point of rocks and is equal to 1100 ° C. At the same time, under the oceans at a depth of 100-200 km the temperature is 100-200 ° C higher than in the continents. The density of matter in layer C at 420 km corresponds to a pressure of 1.4 10 10 Pa and is identified with the phase transition to olivine, which occurs at a temperature of approximately 1600 ° C. At the boundary with the core at a pressure of 1.4 10 11 Pa and temperature At about 4000 °C, silicates are in a solid state, and iron is in a liquid state. In the transition layer F, where iron solidifies, the temperature can be 5000 ° C, in the center of the earth - 5000-6000 ° C, i.e., adequate to the temperature of the Sun.

Earth's atmosphere

The Earth's atmosphere, the total mass of which is 5.15 10 15 tons, consists of air - a mixture of mainly nitrogen (78.08%) and oxygen (20.95%), 0.93% argon, 0.03% carbon dioxide, the rest is water vapor, as well as inert and other gases. Maximum temperature land surface 57-58 ° C (in tropical deserts Africa and North America), minimum - about -90 ° C (in central regions Antarctica).

The Earth's atmosphere protects all living things from the harmful effects of cosmic radiation.

Chemical composition of the Earth's atmosphere: 78.1% - nitrogen, 20 - oxygen, 0.9 - argon, the rest - carbon dioxide, water vapor, hydrogen, helium, neon.

The Earth's atmosphere includes :

troposphere (up to 15 km)
stratosphere (15-100 km)
ionosphere (100 - 500 km).

Between the troposphere and stratosphere there is a transition layer - the tropopause. In the depths of the stratosphere under the influence sunlight an ozone shield is created that protects living organisms from cosmic radiation. Above are the meso-, thermo- and exospheres.

Weather and climate

The lower layer of the atmosphere is called the troposphere. Phenomena that determine the weather occur in it. Due to the uneven heating of the Earth's surface by solar radiation, large masses of air constantly circulate in the troposphere. The main air currents in the Earth's atmosphere are the trade winds in a band of up to 30 ° along the equator and westerly winds temperate zone in the band from 30° to 60°. Another factor in heat transfer is the ocean current system.

Water has a constant cycle on the surface of the earth. Evaporating from the surface of water and land, under favorable conditions, water vapor rises up in the atmosphere, which leads to the formation of clouds. Water returns to the surface of the earth in the form atmospheric precipitation and flows down to the seas and oceans throughout the year.

The amount of solar energy that the Earth's surface receives decreases with increasing latitude. The farther from the equator, the smaller the angle of incidence sun rays to the surface, and the greater the distance that the beam must travel in the atmosphere. As a result average annual temperature at sea level it decreases by about 0.4°C per degree of latitude. The surface of the Earth is divided into latitudinal zones with approximately the same climate: tropical, subtropical, temperate and polar. The classification of climates depends on temperature and precipitation. The most widely recognized is the Köppen climate classification, which distinguishes five broad groups - humid tropics, desert, humid mid-latitudes, continental climate, cold polar climate. Each of these groups is divided into specific groups.

Human influence on the Earth's atmosphere

The Earth's atmosphere is significantly influenced by human activity. About 300 million cars annually emit 400 million tons of carbon oxides, more than 100 million tons of carbohydrates, and hundreds of thousands of tons of lead into the atmosphere. Powerful producers of atmospheric emissions: thermal power plants, metallurgical, chemical, petrochemical, pulp and other industries, motor vehicles.

Systematic inhalation of polluted air significantly worsens people's health. Gaseous and dust impurities can cause air unpleasant odor, irritate the mucous membranes of the eyes, upper respiratory tract and thereby reduce their protective functions, causing chronic bronchitis and lung diseases. Numerous studies have shown that against the background of pathological abnormalities in the body (diseases of the lungs, heart, liver, kidneys and other organs), the harmful effects of atmospheric pollution are more pronounced. Important environmental problem Acid rain began to fall. Every year, when burning fuel, up to 15 million tons of sulfur dioxide enters the atmosphere, which, when combined with water, forms a weak solution of sulfuric acid, which falls to the ground along with rain. Acid rain negatively affect people, crops, buildings, etc.

Ambient air pollution can also indirectly affect the health and sanitary living conditions of people.

The accumulation of carbon dioxide in the atmosphere can cause climate warming as a result of the greenhouse effect. Its essence lies in the fact that a layer of carbon dioxide that freely passes solar radiation to the Earth, will delay the return of thermal radiation to the upper atmosphere. In this regard, the temperature in the lower layers of the atmosphere will increase, which, in turn, will lead to the melting of glaciers, snow, rising levels of oceans and seas, and the flooding of a significant part of the land.

Story

The Earth formed approximately 4540 million years ago from a disk-shaped protoplanetary cloud along with the other planets of the solar system. The formation of the Earth as a result of accretion lasted 10-20 million years. At first the Earth was completely molten, but gradually cooled, and a thin solid shell formed on its surface - the earth's crust.

Shortly after the formation of the Earth, approximately 4530 million years ago, the Moon formed. Modern theory the formation of a single natural satellite of the Earth claims that this occurred as a result of a collision with a massive celestial body, which was called Theia.
The Earth's primary atmosphere was formed as a result of degassing of rocks and volcanic activity. Water condensed from the atmosphere to form the World Ocean. Despite the fact that the Sun by that time was shining 70% weaker than now, geological data shows that the ocean did not freeze, which may be due to greenhouse effect. About 3.5 billion years ago, the Earth's magnetic field formed, protecting its atmosphere from the solar wind.

The formation of the Earth and the initial stage of its development (lasting approximately 1.2 billion years) belong to pre-geological history. The absolute age of the oldest rocks is over 3.5 billion years and, starting from this moment, the geological history of the Earth begins, which is divided into two unequal stages: the Precambrian, which occupies approximately 5/6 of the entire geological chronology (about 3 billion years), and Phanerozoic, covering the last 570 million years. About 3-3.5 billion years ago, as a result of the natural evolution of matter, life arose on Earth, the development of the biosphere began - the totality of all living organisms (the so-called living matter Earth), which significantly influenced the development of the atmosphere, hydrosphere and geosphere (at least in part of the sedimentary shell). As a result of the oxygen catastrophe, the activity of living organisms changed the composition of the Earth's atmosphere, enriching it with oxygen, which created the opportunity for the development of aerobic living beings.

A new factor that has a powerful influence on the biosphere and even the geosphere is the activity of mankind, which appeared on Earth after the appearance of man as a result of evolution less than 3 million years ago (unity regarding dating has not been achieved and some researchers believe - 7 million years ago). Accordingly, in the process of development of the biosphere, formations and further development noosphere - the shell of the Earth on which great influence exerts human activity.

High growth rate of the world population (number earth's population was 275 million in 1000, 1.6 billion in 1900 and approximately 6.7 billion in 2009) and the increasing influence of human society on natural environment raised problems rational use all natural resources and nature conservation.

The Earth is in third place in terms of distance from the Sun. It belongs to the class of terrestrial planets and is the largest in this group. As far as we currently know, what makes Earth unique is that it has life. It was found that age of the earth is about 4.54 billion years old. It was formed from cosmic dust and gas - these were substances left after the Sun was formed.

In the initial period of its existence, our planet was in liquid state. But over time, the reactions slowed down, the temperature dropped, and the Earth's surface began to take a solid form. Gradually an atmosphere began to form. Water appeared on the surface - it entered the atmosphere in the form of ice along with asteroids and other small celestial bodies. The impact of falling comets and asteroids influenced geographical relief Earth, temperature and others climatic conditions on its surface.

How did the satellite of our planet appear? Scientists believe that the Moon was formed as a result of a global astronomical catastrophe, when the Earth tangentially collided with a huge celestial body, not inferior in size to itself. From the fragments of this asteroid, a ring was formed around the Earth, which gradually transformed into the Moon. The Moon has a noticeable influence on our planet; it causes the ebb and flow of the world's oceans, and even leads to a slowdown in the movement of the Earth.

After the emergence of oceans, oxygen began to accumulate in the atmosphere of our planet. There is still no unambiguous theory of the origin of life on earth, but it is believed that as a result of various chaotic interactions of cells with each other, more and more complexly organized cells were formed, which gave rise to the simplest multicellular creatures. Gradually life developed, and over time ozone layer allowed living organisms to reach land.

The surface of the Earth is not static. Continents are in motion, and what can now be seen on the map is the result of constant change. It is believed that the first supercontinent, as a result of some internal or external influences, split into parts and about 550 million years ago formed a new supercontinent Pannotia, and later Pangea, which also began to split about 200 million years ago.

Coastal areas often have a milder climate than areas further inland. For example, climate can be influenced by sea and coastal breezes. The surface of the Earth is heating up many times faster than the waters of the sea. During the daytime, warm air rises from bottom to top, at the same time cold air, which comes from the sea, takes the place of the departed warmer one. As night falls, the reverse process begins to occur. Due to the fact that the water in the sea cools much slower than the land, breezes from the land blow to the sea.

On temperature regime also influenced by numerous ocean currents. Atlantic Ocean intersects diagonally warm current The Gulf Stream begins its crossing in the Gulf of Mexico and ends at the northwestern European coast. Sea winds, which blow over the Gulf Stream towards the coast, create a rather mild climate for this part of Europe, milder than on the coasts of North America, located at the same latitudes. Cold ocean currents also influence the climate. Let’s say that the Benguela Current off the African coasts of the southwestern regions and the western South American coasts cools the tropical zones, otherwise it would be much hotter there.

IN central parts continents, far from the moderating influences of the sea, one can observe a harsh continental climate, which has both hot summers and cold winters.

The word “continent” has Latin roots and if we literally translate the word “continere”, we get the phrase “to stick together”, this word is not always applied to land, but at the same time it implies unity in structure.

The largest continent on Earth is Eurasia. Eurasia includes Europe and Asia, these are two parts of the world in which most of the earth's population lives.

Africa is the Earth's second largest continent, stretching on both sides of the equator.

South America, together with North America, are located in the western part of the Earth, as well as Africa on both sides of the equator. Since these two continents are connected by the narrow Isthmus of Panama, then, in fact, this continent should be considered one large one.

The smallest continent on Earth is Australia. It is almost 100% located in the hot zone in the southern hemisphere.

The highest continent on Earth is Antarctica. This continent is also the most severe in terms of all biological living conditions.

As for countries, they are classified in a variety of ways. For example, they can be classified depending on the size of the territory (the area of Russia is 17 million square kilometers). Countries are also classified according to their characteristics natural world and location, such as tropical European or, for example, mountainous countries. Classification takes place, taking into account the diversity and national composition population (Slavic, mono, Roman, multinational countries), taking into account the forms of government and type political regime. Also classified by degree of independence. The largest countries in the world are identified by various criteria, most often the countries that occupy the largest area are called the largest.

The most major countries of the world by area are considered:

1. Russian Federation – 17,075,400 sq. km.

2. Canada – 9,984,670 sq. km.

3. China – 9,596,960 sq. km.

It's rare to hear that big country on Earth is considered to be China. This option is also correct, because here is the largest population. Finally, there are eight countries in the world that are the largest in terms of their economic achievements.

These countries form " Big Eight": Russia, Japan, Italy, Canada, Germany, France, Great Britain and the leader of the entire chain is the USA, which usually stays out of competition, because it has the highest global GDP. India is a country with the most diverse ethnicity. There are more than five thousand nationalities, peoples and tribes on the territory of India.

Currently, the surface of the Earth, in addition to Antarctica and its islands, is shared by about two hundred states.

Antarctica is the largest geographical area, which does not belong to any country on planet Earth. The international treaty states that only scientific activities can be carried out in Antarctica and the unique nature of this continent must always be preserved.

On our website you can watch from the International space station, and also view it completely free.

Earth - unique planet! Of course, this is true in our solar system and beyond. Nothing that scientists have observed leads to the idea that there are other planets like Earth.

Earth is the only planet orbiting our sun on which we know life exists.

Like no other planet, ours is covered with green vegetation, a vast blue ocean containing more than a million islands, hundreds of thousands of streams and rivers, vast masses of land called continents, mountains, glaciers and deserts that produce a wide variety of colors and textures.

Some forms of life can be found in almost every ecological niche on the surface of the Earth. Even in the very cold of Antarctica, hardy microscopic creatures thrive in ponds, tiny wingless insects live in patches of moss and lichen, and plants grow and bloom annually. From the top of the atmosphere to the bottom of the oceans, from the cold part of the poles to the warm part of the equator, life flourishes. To this day, no signs of life have been found on any other planet.

The Earth is enormous in size, about 13,000 km in diameter, and weighing approximately 5.98 1024 kg. The Earth is on average 150 million km from the Sun. If the Earth goes much faster on its 584 million kilometer journey around the Sun, its orbit will become larger and it will move further away from the Sun. If it is too far from the narrow habitable zone, all life will cease to exist on Earth.

If this ride gets any slower in its orbit, the Earth will move closer to the Sun, and if it moves too close, all life will die as well. The Earth travels around the Sun in 365 days, 6 hours, 49 minutes and 9.54 seconds (a sidereal year), equivalent to more than a thousandth of a second!

If the average annual temperature on the Earth's surface changes by just a few degrees or so, most of the life on it will eventually become fried or frozen. This change will disrupt water-glacier relations and other important balances, with catastrophic results. If the Earth rotates slower than its axis, all life will die in time, either by freezing at night from lack of heat from the Sun or by burning during the day from too much heat.

Thus, our "normal" processes on Earth are undoubtedly unique among our Solar System, and, according to what we know, in the entire Universe:

1. It is a habitable planet. It is the only planet in the solar system that supports life. All forms of life right from the smallest microscopic organisms to huge land and sea animals.

2. Its distance from the Sun (150 million kilometers) is advisable to give it average temperature from 18 to 20 degrees Celsius. It's not as hot as Mercury and Venus, nor as cold as Jupiter or Pluto.

3. It has an abundance of water (71%) that is not found on any other planet. And which is not found on any of the planets known to us in a liquid state so close to the surface.

4. Has a biosphere that provides us with food, shelter, clothing and minerals.

5. Does not have poisonous gases like helium or methane as Jupiter.

6. It is rich in oxygen, which makes life on Earth possible.

7. Its atmosphere acts as a blanket of protection for the Earth from extreme temperatures.

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Earth is the third planet from the Sun. Largest planet terrestrial group by density, diameter, mass. Of all known planets only on Earth there is an oxygen-containing atmosphere, a large amount of water in liquid state of aggregation. The only one known to man a planet on which there is life.

Brief description

The Earth is the cradle of humanity, a lot is known about this planet, but still, all its secrets are at the modern level scientific development we can't figure it out. Our planet is quite small on the scale of the Universe, mass 5.9726 * 10 24 kg, has the shape of a non-ideal ball, its average radius is 6371 km, equatorial radius - 6378.1 km, polar radius - 6356.8 km. The circumference of the great circle at the equator is 40,075.017 km, and at the meridian 40,007.86 km. The volume of the Earth is 10.8 * 10 11 km 3.

The center of rotation of the Earth is the Sun. The movement of our planet occurs within the ecliptic. Rotates in an orbit formed at the beginning of the formation of the solar system. The shape of the orbit is represented as an imperfect circle, the distance from the sun in January is 2.5 million km closer than in June, the average distance from the Sun is considered to be 149.5 million km (astronomical unit).

The Earth rotates from west to east, but the axis of rotation and the equator are tilted relative to the ecliptic. The Earth's axis is not vertical, it is inclined at an angle of 66 0 31' relative to the ecliptic plane. The equator is inclined at 23 0 relative to the Earth's axis of rotation. The Earth's rotation axis does not constantly change due to precession; this change is influenced by the gravitational force of the Sun and Moon, the axis describes a cone around its neutral position, the precession period is 26 thousand years. But in addition to this, the axis also experiences vibrations called nutation, since it cannot be said that only the Earth rotates around the sun, because the Earth-Moon system rotates, they are connected to each other in the form of a dumbbell, the center of gravity of which, called the barycenter, is located inside The Earth is at a distance from the surface of about 1700 km. Therefore, due to nutation, the oscillations superimposed on the precession curve amount to 18.6 thousand years, i.e. The angle of inclination of the earth's axis is relatively constant for a long time, but undergoes minor changes with a periodicity of 18.6 thousand years. The rotation time of the Earth and all solar system around the center of our galaxy - the Milky Way, is 230-240 million years (galactic year).

The average density of the planet is 5.5 g/cm 3 , on the surface the average density is about 2.2-2.5 g/cm 3 , the density inside the Earth is high, its growth occurs spasmodically, the calculation is made using the period of free oscillations, moment of inertia, angular momentum .

Most of the surface (70.8%) is occupied by the World Ocean, the rest is continents and islands.

Gravity acceleration, at ocean level at latitude 45 0: 9.81 m/s 2 .

Earth is a terrestrial planet. Terrestrial planets are characterized by high density and consist predominantly of silicates and metallic iron.

Moon is the only one natural satellite Earth, but there are also a huge number of artificial satellites in orbit.

Education of the planet

The Earth was formed by the accretion of a planetesimal about 4.6 billion years ago. Planetesimals are particles that stick together in a gas and dust cloud. The process of particles sticking together is accretion. The process of contraction of these particles occurred very quickly; for the life of our Universe, several million years are considered an instant. After 17-20 million years from the beginning of formation, the Earth gained the mass of modern Mars. After 100 million years, the Earth has gained 97% of its modern mass.

Initially, the Earth was molten and hot due to strong volcanism and frequent collisions with other celestial bodies. Gradually, the outer layer of the planet cooled and turned into the Earth's crust, which we can now observe.

It is believed that the Moon was formed due to the impact of a celestial body on the surface of the Earth, the mass of which was about 10% of the Earth's mass, as a result of which part of the substance was thrown into low-Earth orbit. Soon the Moon was formed from this material, at a distance of 60 thousand km. As a result of the impact, the Earth received a large impulse, which led to a period of rotation around its axis of 5 hours, and a noticeable tilt of the rotation axis also appeared.

Degassing and volcanic activity created the first atmosphere on Earth. It is assumed that water, i.e. ice and water vapor were carried by comets colliding with the Earth.

Over hundreds of millions of years, the surface of the planet was constantly changing, continents formed and broke apart. They moved along the surface, uniting and forming a continent. This process occurred cyclically. Around 750 million years ago, the earliest known supercontinent Rodinia began to break up. Later, from 600 to 540 million years ago, the continents formed Pannotia and finally Pangea, which broke up 180 million years ago.

We do not have an accurate idea of the age and formation of the Earth; all this data is indirect.

The first photograph taken by Explorer 6.

Observation

Shape and internal structure of the Earth

Planet Earth has 3 different axes: equator, polar and equatorial radii, structurally it is a cardioidal ellipsoid, it has been calculated that the polar regions are slightly elevated relative to other regions and resemble the shape of a heart, the northern hemisphere is elevated 30 meters relative to southern hemisphere. Polar asymmetry of the structure is observed, but nevertheless we believe that the Earth has the shape of a spheroid. Thanks to satellite studies, it was revealed that the Earth has depressions on its surface and a picture of the Earth was presented in the form of a pear, that is, it is a triaxial ellipsoid of rotation. The difference between the geoid and the triaxial ellipsoid is no more than 100 m; this is caused by the uneven distribution of masses both on the surface of the Earth (oceans and continents) and inside it. At each point on the surface of the geoid, the force of gravity is directed perpendicular to it and is an equipotential surface.

The main method for studying the structure of the Earth is the seismological method. The method is based on the study of changes in the velocities of seismic waves depending on the density of matter inside the Earth.

The earth has a layered internal structure. It consists of hard silicate shells (crust and viscous mantle) and a metallic core. The outer part of the core is liquid, and the inner part is solid. The structure of the planet is similar to a peach:

thin crust - the earth's crust, average thickness 45 km (from 5 to 70 km), greatest thickness under large mountains;
layer of the upper mantle (600 km), contains a layer that differs in physical characteristics(decrease in the speed of seismic waves), in which the substance is either heated or slightly melted - a layer called the asthenosphere (50-60 km under the oceans and 100-120 km under the continents).

The part of the Earth that is located together with the earth's crust and the upper part of the mantle, up to the asthenosphere layer, is called the Lithosphere.

The boundary between the upper and lower mantle (depth 660 km) the boundary becomes more and more clear and sharp every year, the thickness is 2 km, the wave speed and composition of the substance changes on it.
The lower mantle reaches a depth of 2700 - 2900 km, thanks to Russian scientists it has been established that there may be another boundary in the lower mantle, i.e. existence of the middle mantle.
The outer core is a liquid substance (depth 4100 km), which does not transmit transverse waves; it is not necessary that this part has the appearance of some kind of liquid, this substance simply has the characteristics of a liquid object.
The inner core is solid, iron with nickel impurities (Fe: 85.5%; Ni: 5.20%), depth 5150 - 6371 km.

All data were obtained indirectly, since wells were not drilled to such a depth, but they are theoretically proven.

The force of gravity at any point on the earth depends on Newtonian gravity, but the placement of density inhomogeneities is important, which explains the inconstancy of gravity. There is an effect of isostasy (balancing), the higher the mountain, the larger the root of the mountain. A striking example of the isostasy effect is an iceberg. There is a paradox in the North Caucasus, there is no balancing, why this happens is still not known.

Earth's atmosphere

Atmosphere - gas shell surrounding the Earth. Conventionally, it borders on interplanetary space at a distance of 1300 km. It is officially believed that the boundary of the atmosphere is determined at an altitude of 118 km, that is, above this distance aeronautics becomes completely impossible.

Air mass (5.1 - 5.3)*10 18 kg. The air density at the sea surface is 1.2 kg/m3.

The appearance of the atmosphere is determined by two factors:

Evaporation of matter from cosmic bodies as they fall to Earth.
Degassing of the earth's mantle is the release of gas during volcanic eruptions.

With the emergence of the oceans and the advent of the biosphere, the atmosphere began to change due to gas exchange with water, plants, animals and the products of their decomposition in soils and swamps.

Atmospheric structure:

The planetary boundary layer is the lowest layer of the gas shell of the planet, the properties and characteristics of which are largely determined by the interaction with the type of surface of the planet (liquid, solid). The thickness of the layer is 1-2 km.
The troposphere is the lower layer of the atmosphere, the most studied, and has different thicknesses at different latitudes: in the polar regions 8-10 km, in moderate latitudes 10-12 km, at the equator 16-18 km.
Tropopause is a transition layer between the troposphere and stratosphere.
The stratosphere is a layer of the atmosphere located at an altitude of 11 km to 50 km. Minor change temperature in the initial layer with a subsequent increase in the layer 25 – 45 km from -56 to 0 0 C.
Stratopause is the boundary layer between the stratosphere and mesosphere. In the stratopause layer, the temperature remains at 0 0 C.
Mesosphere - the layer begins at an altitude of 50 km with a thickness of about 30-40 km. The temperature decreases by 0.25-0.3 0 C with an increase in altitude by 100 m.
Mesopause is a transition layer between the mesosphere and thermosphere. The temperature in this layer fluctuates at -90 0 C.
The thermosphere is the highest point of the atmosphere at an altitude of about 800 km. The temperature rises to altitudes of 200–300 km, where it reaches values of the order of 1500 K, then fluctuates within this limit with increasing altitude. The region of the ionosphere, the place where air ionization occurs (“aurora”) lies inside the thermosphere. The thickness of the layer depends on the level of solar activity.

There is a limit line that separates the Earth's atmosphere and outer space, called the Karman Line. Altitude 100 km above sea level.

Hydrosphere

The total volume of water on the planet is about 1390 million km 3, it is not surprising that 72% of the total area of the Earth is occupied by oceans. Oceans are a very important part of geological activity. The mass of the hydrosphere is approximately 1.46 * 10 21 kg - this is almost 300 times the mass of the atmosphere, but a very small fraction of the mass of the entire planet.

The hydrosphere is divided into the World Ocean, groundwater and surface waters.

The deepest point in the World Ocean (Mariana Trench) - 10,994 meters, average depth ocean is 3800 m.

Surface continental waters occupy only a small proportion of the total mass of the hydrosphere, but nevertheless play a vital role in the life of the terrestrial biosphere, being the main source of water supply, irrigation and water supply. Moreover, this part of the hydrosphere is in constant interaction with the atmosphere and the earth's crust.

Water in a solid state is called the cryosphere.

The water component of the planet's surface determines the climate.

The earth is represented as a magnet, approximated by a dipole (northern and southern polis). At the north pole the force lines go in, and at the south they go out. In fact, at the north pole (geographical) there should be South Pole, and in the southern (geographical) there should be northern, but it was agreed on the contrary. The Earth's rotation axis and the geographic axis do not coincide; the difference in the center of the divergence is about 420-430 km.

The Earth's magnetic poles are not in one place; they are constantly shifting. At the equator, the Earth's magnetic field has an induction of 3.05 10 -5 T and a magnetic moment of 7.91 10 15 T m 3. Tension magnetic field not large, for example, the magnet on the cabinet door is 30 times larger.

Based on the residual magnetization, it was clear that the magnetic field changed its sign many times, several thousand.

The magnetic field forms the magnetosphere, which blocks harmful radiation from the Sun.

The origin of the magnetic field remains a mystery to us; there are only hypotheses, they are that our Earth is a magnetic hydrodynamo. For example, Mercury has no magnetic field.

The time when the magnetic field appeared also remains a problem; it is known that it was 3.5 billion years ago. But more recently, evidence has emerged that in zircon minerals found in Australia, which are 4.3 billion years old, there remains a remanent magnetization, which remains a mystery.

The deepest place on Earth was discovered in 1875 - the Mariana Trench. Deepest point 10,994.

The highest point is Everest, Chomolungma - 8848 meters.

On Kola Peninsula, 10 km west of the city of Zapolyarny, the most deep well in the world. Its depth is 12,262 meters.

Is there a point on our planet where we will weigh less than a mosquito? Yes, there is, the center of our planet, the force of gravitational attraction there is 0, thus, the weight of a person in the center of our planet is less than the weight of any insect on the surface of the Earth.

One of the most beautiful phenomena observed with the naked eye is the aurora - the glow of the upper layers of the planet’s atmosphere, which have a magnetosphere, due to their interaction with charged particles of the solar wind.

Antarctica contains 2/3 fresh water reserves.

If all the glaciers melt, the water level will rise by about 900 meters.

Hundreds of thousands of tons of cosmic dust fall on us every day, but almost everything burns up in the atmosphere.