How did the planets appear?
It would seem scientific and technological progress is able to give answers to many questions concerning the world around us. But scientists still have many mysteries and inaccuracies. After all, sometimes, even the most logical and coherent theory remains only at the level of assumptions, because there are simply no facts to support it, and sometimes it is extremely difficult to obtain evidence. How the planets came to be is one of those open questions, although there are quite a lot of theories and assumptions about this. Let's look at what hypotheses exist regarding the origin of planets.
Main scientific theory
Today there are many different scientific hypotheses, proving where the planets came from, however, in modern natural science adhere to the gas-dust cloud theory.
It lies in the fact that the solar system with all the planets, satellites, stars and other celestial bodies appeared as a result of compression of the gas and dust cloud. In its center the most big star- Sun. And all other bodies appeared from the Kuiper belt and the Oort cloud. If we talk in simple language, then the planets appeared as follows. There was some matter in space that consisted only of gas and dust dissolved in it. After strong exposure to atmospheric pressure, the gas began to compress, and the dust began to turn into large and heavy objects, which later became planets.
Kuiper Belt and Oort Cloud
We have already mentioned the Kuiper belt and the Oort cloud earlier. Scientists say that it was these two objects that became the building material from which the planets emerged.
The Kuiper Belt is a zone in the Solar System that begins from the orbit of Neptune. It is believed that this is an asteroid belt, but this is not entirely true. It is several times larger and more massive than it. In addition, the Kuiper belt differs from the asteroid belt in that it consists of volatile substances such as ammonia and water. Today it is believed that it was in this belt that three dwarf planets arose - Pluto, Huamea, Makemake, as well as their satellites.
The second object that contributed to the formation of planets, the Oort cloud, has not yet been found, and its existence has only been confirmed hypothetically. It is an internal and external cloud consisting of isotopes of carbon and nitrogen with solid bodies moving in it. It is believed that this is a certain spherical region of the solar system, which is the source of the emergence of comets, which are also the building material for the emergence of other planets. If you imagine how the planets appeared externally, then you can imagine how dust and other solid bodies were compressed, as a result of which they acquired the spherical shape in which we know them today.
Alternative scientific hypotheses
- So, the first of such researchers was Georges-Louis Buffon. In 1745, he suggested that all planets appeared as a result of the ejection of matter after the collision of the Sun with a passing comet. The comet broke up into many parts, which, under the influence of the centrifugal and centripetal forces of the Sun's energy, formed planets solar system.
- A little later, in 1755, a researcher named Kant suggested that all planets were formed due to the fact that dust particles under the influence of gravity formed the planets.
- In 1706, French astronomer Pierre Laplace put forward his alternative theory of the appearance of planets. He believed that initially a huge hot nebula consisting of gas formed in space. She slowly rotated in outer space, but the centrifugal force increasing as a result of movement was the basis for the emergence of planets. The planets appeared at certain points, which were located in rings left along the path. In total, Laplace said, 10 rings separated, which broke up into 9 planets and an asteroid belt.
- And in the 20th century, Fred Hoyle put forward his hypothesis about how the planets appeared. He believed that the Sun had a twin star. Fred argued that this star exploded, resulting in the formation of planets.
- But not only science tries to understand where the planets came from, religion also tries to explain this interesting question. So, there is the theory of creationism. It says that all space objects, including the planets of the solar system, were created by the creator, God.
And these are not all the hypotheses that exist today. If you want to see with your own eyes how the planets came into being, videos can be found on the Internet, as well as in some electronic astronomy textbooks.
We all live on planet Earth, I think each of us is interested in how our planet was formed. Scientists have hypotheses on this issue.
How did planet earth appear?
The earth was formed approximately 4.5 billion years ago. It is believed that this the only planet in the Universe, which is inhabited by living beings. Astronomy researchers claim that the Earth emerged from cosmic dust and gas that remained after the formation of the Sun. They also claim that the Earth was originally a molten mass without any life. But then water began to accumulate and the surface began to harden. Asteroids, comets and the energy of the Sun formed the relief and climate of the Earth that we know today.
If you are seriously interested in the question of how planet Earth came to be, a video that is quite easy to find will clearly tell you about this issue.
Now you know how the planets of the solar system appeared. Astronomers have not yet reached a consensus on this issue, but I would like to believe that the development of science and technology in the near future will allow us to collect evidence and say exactly how the planets appeared.
When a star is young, it is always surrounded by a primary rotating disk of gas and dust from which cosmic objects are formed. Astronomers are always hunting for such structures because they can capture the moment not only of the formation of a star, but also record the process of planet formation.
However, finding such disks around brown dwarfs or very low-mass stars is extremely difficult. But this time, scientists discovered four (!) new objects with low mass, surrounded by disks.
Three of them are extremely small - only 13 or 18 times the mass of Jupiter. The fourth is approximately 120 times the mass of Jupiter (For comparison: the Sun is 1000 times larger than Jupiter).
What's even more interesting is that the two stars are approximately 42 and 45 million years old. It turns out that these are the youngest objects ever found surrounded by active planet-forming disks.
Finding a cloud of gas and dust belonging to a brown dwarf with an extremely low mass is even more interesting, because its further development will allow us to learn a lot about the evolution of stars and planets.
How does the formation and development of celestial structures occur?
In a gas-dust disk, grains of dust collide, combine, forming larger fragments that grow into rocks, then the stage of planetesimals, planetary embryos begins, and finally the stage of transformation into rocky terrestrial planets begins (some of which become the core of gas giants).
Astronomers typically identify clouds of gas and dust this way: the star heats up the surrounding dust, which acquires properties that make it visible through telescopes with infrared cameras.
How to understand whether the formation of planets is complete?
However, some disks show that the formation of celestial bodies is not ongoing, but has already been completed. These disks are formed from fragments remaining after the process of planet formation and as a result of subsequent collisions of already created celestial objects. Ultimately, these remaining dust disperse into interplanetary space.
Some disks even represent a transitional stage between the phases of planet formation and its end.
It is important for scientists to distinguish between these types of disks because as a result they will be able to better chart the birth and changes over time of planetary systems, including the Solar System.
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This space object has long attracted the attention of science fiction writers, scientists, and researchers. It rains here, numerous rivers flow into the seas and oceans. Scientists believe that a person can easily walk on its surface without much risk to life (if he takes with him a very thick waterproof suit and does not forget to put on an oxygen mask). To[…]
The origin of life on Earth occurred about 3.8 billion years ago, when the formation of the earth's crust ended. Scientists have found that the first living organisms appeared in aquatic environment, and only a billion years later the first creatures appeared on the surface of the land.
The formation of terrestrial flora was facilitated by the formation of organs and tissues in plants and the ability to reproduce by spores. Animals also evolved significantly and adapted to life on land: internal fertilization, the ability to lay eggs, and pulmonary respiration appeared. An important stage in development was the formation of the brain, conditioned and unconditioned reflexes, survival instincts. The further evolution of animals provided the basis for the formation of humanity.
Dividing the history of the Earth into eras and periods gives an idea of the features of the development of life on the planet in different time periods. Scientists highlight significant events in the formation of life on Earth in separate periods of time - eras, which are divided into periods.
There are five eras:
- Archean;
- Proterozoic;
- Paleozoic;
- Mesozoic;
- Cenozoic.
Archean era began about 4.6 billion years ago, when planet Earth was just beginning to form and there were no signs of life on it. The air contained chlorine, ammonia, hydrogen, the temperature reached 80°, the level of radiation exceeded permissible limits, under such conditions the origin of life was impossible.
It is believed that about 4 billion years ago our planet collided with celestial body, and the consequence was the formation of the Earth’s satellite, the Moon. This event became significant in the development of life, stabilized the planet’s rotation axis, and contributed to the purification of water structures. As a result, the first life arose in the depths of the oceans and seas: protozoa, bacteria and cyanobacteria.
The Proterozoic era lasted from approximately 2.5 billion years ago to 540 million years ago. Residues discovered unicellular algae, shellfish, annelids. Soil begins to form.
The air at the beginning of the era was not yet saturated with oxygen, but in the process of life, bacteria inhabiting the seas began to increasingly release O 2 into the atmosphere. When the amount of oxygen was at a stable level, many creatures took a step in evolution and switched to aerobic respiration.
The Paleozoic era includes six periods.
Cambrian period(530 – 490 million years ago) is characterized by the emergence of representatives of all species of plants and animals. The oceans were inhabited by algae, arthropods, and mollusks, and the first chordates (haikouihthys) appeared. The land remained uninhabited. The temperature remained high.
Ordovician period(490 – 442 million years ago). The first settlements of lichens appeared on land, and megalograptus (a representative of arthropods) began to come ashore to lay eggs. In the depths of the ocean, vertebrates, corals, and sponges continue to develop.
Silurian(442 – 418 million years ago). Plants come to land, and the rudiments of lung tissue form in arthropods. The formation of the bone skeleton in vertebrates is completed, and sensory organs appear. Mountain building is underway and different climatic zones are being formed.
Devonian(418 – 353 million years ago). The formation of the first forests, mainly ferns, is characteristic. Bone and cartilaginous organisms appear in reservoirs, amphibians began to come to land, and new organisms—insects—are formed.
Carboniferous period(353 – 290 million years ago). The appearance of amphibians, the subsidence of the continents, at the end of the period there was a significant cooling, which led to the extinction of many species.
Permian period(290 – 248 million years ago). The earth is inhabited by reptiles; therapsids, the ancestors of mammals, appeared. The hot climate led to the formation of deserts, where only hardy ferns and some conifers could survive.
The Mesozoic era is divided into 3 periods:
Triassic(248 – 200 million years ago). Development of gymnosperms, appearance of the first mammals. The split of land into continents.
Jurassic period(200 - 140 million years ago). Emergence angiosperms. The appearance of the ancestors of birds.
Cretaceous period(140 – 65 million years ago). Angiosperms (flowering plants) became the dominant group of plants. Development of higher mammals, true birds.
The Cenozoic era consists of three periods:
Lower Tertiary period or Paleogene(65 – 24 million years ago). The disappearance of most cephalopods, lemurs and primates appear, later parapithecus and dryopithecus. Development of ancestors modern species mammals - rhinoceroses, pigs, rabbits, etc.
Upper Tertiary period or Neogene(24 – 2.6 million years ago). Mammals inhabit land, water, and air. The appearance of Australopithecines - the first ancestors of humans. During this period, the Alps, Himalayas, and Andes were formed.
Quaternary or Anthropocene(2.6 million years ago – today). Significant event period - the appearance of man, first the Neanderthals, and soon Homo sapiens. Vegetable and fauna acquired modern features.
It arose about 4600 million years ago. Since then, its surface has constantly changed under the influence of various processes. The earth apparently formed several million years after a colossal explosion in space. The explosion created a huge amount of gas and dust. Scientists believe that its particles, colliding with each other, united into giant clumps of hot matter, which over time turned into the existing planets.
According to scientists, the Earth arose after a colossal cosmic explosion. The first continents probably formed from molten rock flowing to the surface from vents. As it solidified, it made the earth's crust thicker. Oceans could have formed in the lowlands from droplets contained in volcanic gases. The original one probably consisted of the same gases.
It is thought that the Earth was at first incredibly hot, with a sea of molten rocks on the surface. About 4 billion years ago, the Earth began to slowly cool and split into several layers (see right). The heaviest rocks sank deep into the bowels of the Earth and formed its core, remaining unimaginably hot. Less dense matter formed a series of layers around the core. On the surface itself, molten rocks gradually hardened, forming a solid crust covered with many volcanoes. The molten rock, bursting to the surface, froze, forming the earth's crust. Low areas filled with water.
Earth today
Although the earth's surface seems solid and unshakable, changes are still taking place. They are caused by various kinds of processes, some of which destroy the earth's surface, while others recreate it. Most changes occur extremely slowly and are detected only by special devices. It takes millions of years for the formation of a new mountain range, but a powerful volcanic eruption or a monstrous earthquake can transform the surface of the Earth in a matter of days, hours and even minutes. In 1988, an earthquake in Armenia that lasted about 20 seconds destroyed buildings and killed more than 25,000 people.
Structure of the Earth
In general, the Earth has the shape of a ball, slightly flattened at the poles. It consists of three main layers: crust, mantle and core. Each layer is formed by different types of rocks. The picture below shows the structure of the Earth, but the layers are not to scale. Outer layer called the earth's crust. Its thickness is from 6 to 70 km. Beneath the crust is the upper layer of the mantle, formed by hard rock. This layer, together with the crust, is called and has a thickness of about 100 km. The part of the mantle underlying the lithosphere is called the asthenosphere. It is approximately 100 km thick and is likely composed of partially molten rocks. The mantle varies from 4000°C near the core to 1000°C in the upper part of the asthenosphere. The lower mantle probably consists of solid rock. The outer core is composed of iron and nickel, apparently molten. The temperature of this layer can reach 5500°C. The temperature of the subcore can be above 6000°C. It is solid due to the colossal pressure of all the other layers. Scientists believe that it consists mainly of iron (more about this in the article ““).
The Earth is the object of study for a significant amount of geosciences. The study of the Earth as a 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 the 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 and 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 differentiation of the Earth's substance, under the influence of its gravitational field, under conditions of heating of the earth's interior, various types of chemical composition, state of aggregation And physical properties shells - 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, is locus 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 the level of the world's oceans by an average of 875 m (the highest height is 8848 m - Mount Chomolungma), mountains occupy more than 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 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 speed 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, the Earth is divided into a particularly strong layer, the lithosphere, and the next, softened layer - 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. On lower limit the earth's crust, the Mohorovicic surface, the velocities of seismic waves increase abruptly, which is associated primarily 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.
It is believed that the upper mantle is close 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, making it possible to explain the state of matter in various layers and build a general picture of 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 land surface temperature 57-58 °C (in tropical deserts of Africa and North America), the minimum is about -90 ° C (in the central regions of 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).
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 the band up to 30° along the equator and the westerly winds of the 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 waters and land, when favorable conditions water vapor rises in the atmosphere, leading to the formation of clouds. Water returns to the surface of the earth in the form of 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 further from the equator, the smaller the angle of incidence of the sun's rays on the surface, and the greater the distance that the ray must travel in the atmosphere. As a consequence, the average annual temperature at sea level 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 give the air an unpleasant odor, irritate the mucous membranes of the eyes and upper respiratory tract and thereby reduce their protective functions, and cause 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 fuel is burned, 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.
Pollution atmospheric air may 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 Earth, will delay returns to the upper atmosphere thermal radiation. 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 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 named 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 70% weaker than it is now, geological data shows that the ocean did not freeze, which may be due to the greenhouse effect. About 3.5 billion years ago, the Earth's magnetic field formed, protecting its atmosphere from the solar wind.
Earth Education and initial stage its development (lasting approximately 1.2 billion years) belongs to pre-geological history. The absolute age of the oldest rocks is over 3.5 billion years and, starting from this moment, counts down geological history Earth, which is divided into two unequal stages: the Precambrian, which occupies approximately 5/6 of the entire geological chronology (about 3 billion years), and the 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 of the noosphere are distinguished - the shell of the Earth, which is greatly influenced by human activity.
The high rate of growth of the world's population (the world 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 the natural environment have raised problems rational use everyone natural resources and nature conservation.
