This layer rests on the upper mantle, the density of which is significantly higher.

The density and chemical composition of the mantle, according to seismic waves, differ sharply from the corresponding characteristics of the nucleus. The mantle is formed by various silicates (compounds based on silicon). It is assumed that the composition of the lower mantle is similar to the composition of stone meteorites, chondrites.

The upper mantle is directly connected with the outermost layer – the bark. It is considered to be a kitchen where many bark-forming rocks and their semi-finished products are prepared. It is believed that the upper mantle consists of olivine (60%), pyroxene (30%) and feldspar (10%). In certain areas of this layer there is a partial melting of minerals, and alkaline basalts are formed – the basis of the oceanic crust. Through the rift faults of the mid-ocean ridges, basalts come from the mantle to the Earth’s surface.

But this does not limit the interaction of the crust and mantle. The fragile crust, which has a high degree of rigidity, together with part of the underlying mantle forms a special layer about 100 km thick, called the lithosphere. This layer rests on the upper mantle, the density of which is significantly higher. The upper mantle has a feature that determines the nature of its interaction with the lithosphere: in relation to short-term loads, it behaves as a rigid material, and in relation to long-term loads – as plastic. The lithosphere creates a constant load on the upper mantle and under its pressure, the underlying layer, called the asthenosphere, exhibits plastic properties, the lithosphere “floats” in it. This effect is called isostasis.

The asthenosphere, in turn, relies on the deeper layers of the mantle, the density and viscosity of which increase with depth. The reason for this is rock compression, which causes structural rearrangement of some chemical compounds. Silicates that make up this modification of silicon have a very compact structure, they predominate in the lower mantle. In general, the lithosphere, asthenosphere and the rest of the mantle can be considered as a three-layer system, each of the parts of which is movable relative to the other components. The light lithosphere, which relies on a not very viscous and plastic asthenosphere, has a special mobility.

The Earth’s crust, which forms the upper part of the lithosphere, consists mainly of eight chemical elements: oxygen, silicon, aluminum, iron, calcium, magnesium, sodium and potassium. Half of the total mass of the crust is accounted for by oxygen, which is contained in it in bound states, mainly in the form of metal oxides. The geological features of the crust are determined by the combined action of the atmosphere, hydrosphere and biosphere – these three outermost shells of the planet.

The composition of the cortex and outer shells is constantly updated, which will illustrate the following data. Due to weathering and wear, the matter of the continental surface is completely renewed in 80-100 million years. The decline of the matter of the continents is filled by age-old raised crusts. The activity of bacteria, plants and animals is accompanied by a complete change in the carbon dioxide contained in the atmosphere in 6-7 years, oxygen – in 4000 years. The entire mass of water in the hydrosphere (1.4 * 1018 tons) is completely renewed in 10 million years. An even more fundamental cycle of matter on the surface of the planet takes place in the processes that connect all the inner shells into a single system.

There are stationary vertical flows, called mantle jets, they rise from the lower mantle to the upper and deliver there a hotter substance. The phenomena of the same nature include inside the plate “hot fields” with which, in particular, are associated the largest anomalies in the form of the terrestrial geoid. In such places there is a rise in the ocean surface by 50-70 m from the strict line of the geoid. So the way of life of the earth’s interior is extremely complex. Deviations from the mobilist positions do not undermine the idea of ​​tectonic plates and their horizontal movements. But it is possible that in the near future there will be a more general theory of the planet, which takes into account the horizontal motions of the plates and the open vertical transfer of hot matter in the mantle.

The uppermost shells of the Earth – the hydrosphere and atmosphere – are markedly different from other shells, creating a solid body of the planet. By weight it is a very small part of the globe, no more than 0.025% of its total mass. But the importance of these shells in the life of the planet is huge. The hydrosphere and atmosphere emerged at an early stage in the formation of the planet, and perhaps simultaneously with its formation. There is no doubt that the ocean and atmosphere existed 3.8 billion years ago.

The formation of the Earth was in line with a single process that caused the chemical differentiation of the subsoil and the emergence of the predecessors of modern hydrosphere and atmosphere. First, the protonucleus of the Earth formed from the grains of heavy non-volatile substances, then it very quickly joined the substance, which later became a mantle. And when the Earth reached about the size of Mars, the period of its bombardment by planetosimals began. The shocks were accompanied by strong local warming and melting of terrestrial rocks and planetosimals.

At the same time gases and water vapors contained in the rocks were released. And because the average surface temperature of the planet remained low, water vapor condensed to form a growing hydrosphere. In these collisions, the Earth lost hydrogen and helium, but retained heavier gases. The content of isotopes of inert gases in the modern atmosphere allows us to judge the source, their originator. This isotopic composition is consistent with the hypothesis of the shock origin of gases and water, but contradicts the hypothesis of the process of gradual degassing of the earth’s interior as a source of hydrosphere and atmosphere. The ocean and atmosphere, of course, existed not only throughout the history of the Earth as a planet, but also during the main phase of accretion, when the proto-Earth was the size of Mars.

The idea of ​​shock degassing, which is considered the main mechanism of formation of the hydrosphere and atmosphere, is gaining more and more recognition. Laboratory experiments have confirmed the ability of shock processes to emit significant amounts of gases from terrestrial rocks, including molecular oxygen. This means that some oxygen was present in the Earth’s atmosphere before the biosphere appeared on it. Ideas of abiogenic origin of some of the atmospheric oxygen were put forward by other scientists.

Conclusion. Both outer shells – the hydrosphere and atmosphere – interact closely with each other and with the rest of the Earth’s shell, especially with the lithosphere. They are directly affected by the Sun and space. Each of these shells is an open system that has a certain autonomy and its own internal laws of development.

Everyone who studies air or water oceans is convinced that the objects of study find a strange subtlety of organization, the ability to regulate. But none of the terrestrial systems falls out of the general ensemble, and their coexistence demonstrates not just the sum of the parts, but a new quality.

Among the community of the Earth’s crust, a special place is occupied by the biosphere. It captures the upper layer of the lithosphere, almost the entire hydrosphere and the lower atmosphere. The term “biosphere” was introduced into science in 1875 by the Austrian geologist E. Suess (1831-1914). The biosphere was understood as a set of living matter inhabiting the surface of the planet together with the uninhabited environment.

VI Vernadsky added a new meaning to this concept, considering the biosphere as a systemic formation, as a geological shell of the Earth. The significance of this system goes beyond the purely terrestrial world, it is a link on a cosmic scale.

11/14/2011

Earth as a planet in the solar system. Abstract

In a sense, the Earth is distinguished by nature itself: in the solar system only on this planet there are developed life forms, only on it the local ordering of matter has reached an extremely high degree, continuing the general line of matter

The solar system is a group of celestial bodies, very different in size and physical structure. This group includes: the Sun, nine large planets, dozens of satellites, thousands of small planets (asteroids), hundreds of comets, countless meteorite bodies moving in swarms and in the form of individual particles. All these bodies are connected into one system due to the gravitational force of the central body – the Sun.

The solar system is a very complex natural formation, combining the variety of its constituent elements with the highest stability of the system as a whole.

According to E. Tsiolkovsky, the Earth is the cradle of humanity.

In a sense, the Earth is distinguished by nature https://123helpme.me/a-tree-grows-in-brooklyn/ itself: in the solar system only on this planet there are developed life forms, only on it the local ordering of matter has reached an extremely high degree, continuing the general line of development of matter. It is on Earth that the most difficult stage of self-organization has passed, which marks a deep qualitative leap to higher forms of order.

The difference between the planets of the terrestrial group from the giant planets is obvious. But among the nearest neighbors of the Earth there are no two identical planets: they all differ in size, physicochemical parameters, the structure of the subsoil and surfaces, atmospheres and other characteristics. The main differences are determined by the initial conditions of planet formation – chemical composition, density of matter in those parts of the protoplanetary cloud, where these planets formed, the distance from the Sun, resonant interactions with other planetary bodies and the Sun.

Direct research on other nearby planets has only just begun. However, the available information already allows for a comparative study of the outer shells of the Earth and other planets in the solar system. On this basis, a new scientific field called comparative planetology.

Earth is the largest planet in its group. But even such dimensions and mass are minimal, at which the planet is able to maintain its gaseous atmosphere. The Earth is intensively losing hydrogen and some other light gases, which confirm the observations of the so-called Earth’s plume. Venus is almost equal in size and mass to Earth, but it is closer to the Sun and receives more heat from it. Therefore, it has long lost all free hydrogen. The other two planets in this group either do not have an atmosphere (Mercury) or remain in a very depleted state (Mars).

The planets closest to the Sun – Mercury and Venus – rotate very slowly around the axis, with a period of tens to hundreds of Earth days. The slow rotation of these planets is due to their resonant interactions with the Sun and with each other. Earth and Mars rotate with almost equal periods of about 24 hours.

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