There are inner and outer shells interacting with each other.
The internal structure of the Earth
To study the internal structure of the Earth, drilling of ultra-deep wells is used (the deepest Kola - 11,000 m. has passed less than 1/400 of the earth's radius). But most of the information about the structure of the Earth was obtained using the seismic method. Based on the data obtained by these methods, a general model of the Earth's structure was created.
In the center of the planet is the earth's core - (R = 3500 km) presumably consists of iron with an admixture of lighter elements. There is a hypothesis that the core consists of hydrogen, which under high can go into a metallic state. The outer layer of the core is a liquid, molten state; the inner core with a radius of 1250 km is solid. The temperature in the center of the core, apparently, is up to 5 - 6 thousand degrees.
The core is surrounded by a shell - the mantle. The mantle has a thickness of up to 2900 km, the volume is 83% of the planet's volume. It consists of heavy minerals rich in magnesium and iron. Despite the high temperature (above 2000?), most of the mantle substance is in a solid crystalline state due to the enormous pressure. The upper mantle at a depth of 50 to 200 km has a mobile layer called the asthenosphere (weak sphere). It is characterized by high plasticity, due to the softness of the substance that forms it. It is with this layer that other important processes on Earth are associated. Its thickness is 200-250 km. The substance of the asthenosphere, penetrating into the earth's crust and pouring out to the surface, is called magma.
The Earth's crust is a hard layered outer shell of the Earth with a thickness of 5 km under the oceans to 70 km under the mountain structures of the continents.
- Continental (mainland)
- Oceanic
The continental crust is thicker and more complex. It has 3 layers:
- Sedimentary (10-15 km, mostly sedimentary)
- Granite (5-15 km., the rocks of this layer are mostly metamorphic, similar in properties to granite)
- Balsat (10-35 km., the rocks of this layer are igneous)
The oceanic crust is heavier, there is no granite layer in it, the sedimentary layer is relatively thin, it is mostly balsatic.
In the areas of transition from the mainland to the ocean, the crust has a transitional character.
The earth's crust and the upper part of the mantle form a shell, which is called (from the Greek litos - stone). The lithosphere is a solid shell of the Earth, including the earth's crust and the upper layer of the mantle, lying on the hot asthenosphere. The thickness of the lithosphere is on average 70–250 km, of which 5–70 km falls on the earth's crust. The lithosphere is not a continuous shell, it is divided into giant faults. Most plates include both continental and oceanic crust. There are 13 lithospheric plates. But the largest are: American, African, Indo-Australian, Pacific.
Under the influence of processes occurring in the bowels of the earth, the lithosphere makes movements. Lithospheric plates slowly move relative to each other at a speed of 1 - 6 cm per year. In addition, their vertical movements are constantly occurring. The set of horizontal and vertical movements of the lithosphere, accompanied by the occurrence of faults and folds of the earth's crust, are called. They are slow and fast.
The forces causing the divergence of lithospheric plates arise when the mantle substance moves. Powerful ascending flows of this substance push apart the plates, break the earth's crust, forming deep faults in it. Where this material rises outward, faults appear in the lithosphere, and the plates begin to move apart. The magma that intrudes along the faults, solidifying, builds up the edges of the plates. As a result, swells appear on both sides of the fault, and . They are found in all oceans and form a single system with a total length of 60,000 thousand km. The height of the ridges is up to 3000 m. Such a ridge reaches its greatest width in the southeastern part, where the rate of plate expansion is 12 - 13 cm / year. It does not occupy a middle position and is called the Pacific Rise. At the fault site, in the axial part of the mid-ocean ridges, there are usually gorges - rifts. Their width varies from several tens of kilometers in the upper part to several kilometers at the bottom. At the bottom of the rifts are small volcanoes and hot springs. In rifts, rising magma creates new oceanic crust. The farther from the rift, the older the crust.
Collision of lithospheric plates is observed along other plate boundaries. It happens in different ways. When a plate collides with the oceanic crust and the plate with the continental crust, the first subsides under the second. In this case, deep-sea trenches, island arcs, and mountains on land appear. If two plates collide with the continental crust, then collapse occurs, volcanism and the formation of mountainous regions (for example, these are complex processes that occur during the movement of magma, which forms in separate chambers and at different depths of the asthenosphere. Very rarely it forms in the earth's crust. There are two main types of magmas - basaltic (basic) and granitic (acidic).
As magma erupts on the Earth's surface, it forms volcanoes. Such magmatism is called effusive. But more often, magma is introduced into the earth's crust along cracks. Such magmatism is called intrusive.
The bowels of the Earth are very mysterious and practically inaccessible. Unfortunately, there is still no such apparatus with which you can penetrate and study the internal structure of the Earth. The researchers found that at the moment the deepest mine in the world has a depth of 4 km, and the deepest well is located on the Kola Peninsula and is 12 km.
However, certain knowledge about the depths of our planet is still established. Scientists have studied its internal structure using the seismic method. The basis of this method is the measurement of vibrations during an earthquake or artificial explosions produced in the bowels of the Earth. Substances with different density and composition passed vibrations through themselves at a certain speed. This made it possible to measure this speed with the help of special instruments and analyze the results obtained.
Scientists' opinion
The researchers found that our planet has several shells: the earth's crust, mantle and core. Scientists believe that about 4.6 billion years ago, the stratification of the bowels of the Earth began and continues to stratify to this day. In their opinion, all heavy substances descend to the center of the Earth, joining the planet's core, while lighter substances rise up and become the earth's crust. When the internal stratification ends, our planet will turn into a cold and dead one.
Earth's crust
It is the thinnest shell of the planet. Its share is 1% of the total mass of the Earth. People live on the surface of the earth's crust and extract from it everything necessary for survival. In the earth's crust, in many places, there are mines and wells. Its composition and structure is studied using samples collected from the surface.
Mantle
Represents the most extensive shell of the earth. Its volume and mass is 70 - 80% of the entire planet. The mantle is solid but less dense than the core. The deeper the mantle is located, the greater its temperature and pressure become. The mantle has a partially melted layer. With the help of this layer, solids move to the core of the earth.
Core
It is the center of the earth. It has a very high temperature (3000 - 4000 o C) and pressure. The core consists of the densest and heaviest substances. It is approximately 30% of the total mass. The solid part of the core floats in its liquid layer, thereby creating the earth's magnetic field. It is the protector of life on the planet, protecting it from cosmic rays.
Non-fiction film about shaping our world
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The planet Earth belongs to the terrestrial planets, this indicates that the surface of the Earth is solid and the structure and composition of the Earth is in many ways similar to other terrestrial planets. Earth is the largest terrestrial planet. The Earth has the largest size, mass, strength of gravity and magnetic field. The surface of the planet Earth is still very (by astronomical standards) young. 71% of the planet's surface is occupied by a water shell and this makes the planet unique; on other planets, water on the surface could not be in a liquid state due to inappropriate temperatures of the planets. The ability of the oceans to store the heat of the water, allows you to coordinate the climate, transferring this heat to other places with the help of a current (the most famous warm current is the Gulf Stream in the Atlantic Ocean).
The structure and composition is similar to many other planets, but there are still significant differences. In the composition of the earth, you can find all the elements of the periodic table. Everyone knows the structure of the Earth from an early age: a metal core, a large layer of the mantle and, of course, the earth's crust with a wide variety of topography and internal composition.
The composition of the earth.
By studying the mass of the Earth, scientists came to the conclusion that the planet consists of 32% iron, 30% oxygen, 15% silicon, 14% magnesium, 3% sulfur, 2% nickel, 1.5% of the earth consists of calcium and 1.4 % from aluminum, and the remaining elements account for 1.1%.
The structure of the earth.
The Earth, like all the planets of the terrestrial group, has a layered structure. At the center of the planet is a core of molten iron. The interior of the core is made of solid iron. The entire core of the planet is surrounded by viscous magma (harder than under the surface of the planet). The core also includes molten nickel and other chemical elements.
The planet's mantle is a viscous shell that accounts for 68% of the planet's mass and about 82% of the planet's total volume. The mantle is made up of silicates of iron, calcium, magnesium, and many others. The distance from the Earth's surface to the core is more than 2800 km. and all this space is occupied by the mantle. Usually the mantle is divided into two main parts: upper and lower. Above the mark of 660 km. to the earth's crust is the upper mantle. It is known that, from the time of the formation of the Earth to the present day, it has undergone significant changes in its composition, it is also known that it was the upper mantle that gave rise to the earth's crust. The lower mantle is located, respectively, below the boundary of 660 km. to the core of the planet. The lower mantle has been little studied due to difficult accessibility, but scientists have every reason to believe that the lower mantle has not undergone major changes in its composition over the entire existence of the planet.
The earth's crust is the outermost, hardest shell of the planet. The thickness of the earth's crust remains within the range of 6 km. at the bottom of the oceans and up to 50 km. on the continents. The earth's crust, like the mantle, is divided into 2 parts: the oceanic crust and the continental crust. The oceanic crust consists mainly of various rocks and sedimentary cover. The continental crust consists of three layers: sedimentary cover, granite and basalt.
During the life of the planet, the composition and structure of the Earth underwent significant changes. The relief of the planet is constantly changing, the tectonic plates either shift, forming large mountainous reliefs at the place of their junction, or move apart, creating seas and oceans between them. The movement of tectonic plates is due to changes in the temperatures of the mantle below them and under various chemical influences. The composition of the planet was also subjected to various external influences, which led to its change.
At one point, the Earth reached the point where life could appear on it, which happened. lasted a very long time. Over these billions of years, it has been able to develop or mutate from a single-celled organism into multicellular and complex organisms, which is what a person is.
Our house
The planet on which we live is used by us in absolutely all spheres of our life: we build our cities and dwellings on it; we eat the fruits of plants growing on it; use for our own purposes the natural resources extracted from its bowels. The earth is the source of all the blessings available to us, our home. But few people know what the structure of the Earth is, what are its features and why it is interesting. For people who are specifically interested in this issue, this article is written. Someone, having read it, will refresh the knowledge they already have in their memory. And someone, perhaps, will find out something that he had no idea about. But before moving on to talking about what characterizes the internal structure of the Earth, it is worth saying a little about the planet itself.
Briefly about the planet Earth
Earth is the third planet from the Sun (Venus is in front of it, Mars is behind it). The distance from the Sun is about 150 million km. It belongs to a group of planets called the "earth group" (also includes Mercury, Venus and Mars). Its mass is 5.98 * 10 27, and the volume is 1.083 * 10 27 cm³. The orbital speed is 29.77 km/s. The Earth makes a complete revolution around the Sun in 365.26 days, and a complete revolution around its own axis - in 23 hours 56 minutes. Based on scientific data, scientists have concluded that the age of the Earth is approximately 4.5 billion years. The planet has the shape of a ball, but its outlines sometimes change due to inevitable internal dynamic processes. The chemical composition is similar to that of the rest of the terrestrial planets - it is dominated by oxygen, iron, silicon, nickel and magnesium.
Earth structure
The earth consists of several components - this is the core, the mantle and the earth's crust. A little about everything.
Earth's crust
This is the top layer of the earth. It is he who is actively used by a person. And this layer is the best studied. It contains deposits of rocks and minerals. It consists of three layers. The first is sedimentary. It is represented by softer rocks formed as a result of the destruction of solid rocks, deposits of plant and animal remains, and sedimentation of various substances on the bottom of the world's oceans. The next layer is granite. It is formed from solidified magma (molten substance of the earth's depths that fills cracks in the crust) under conditions of pressure and high temperatures. Also, this layer contains various minerals: aluminum, calcium, sodium, potassium. As a rule, this layer is absent under the oceans. After the granite layer comes the basalt layer, consisting mainly of basalt (a rock of deep origin). This layer contains more calcium, magnesium and iron. These three layers contain all the minerals that a person uses. The thickness of the earth's crust ranges from 5 km (under the oceans) to 75 km (under the continents). The Earth's crust makes up about 1% of its total volume.
Mantle
It is located under the cortex and surrounds the nucleus. It makes up 83% of the total volume of the planet. The mantle is divided into upper (at a depth of 800-900 km) and lower (at a depth of 2900 km) parts. From the upper part, magma is formed, which we mentioned above. The mantle consists of dense silicate rocks, which contain oxygen, magnesium and silicon. Also on the basis of seismological data, scientists came to the conclusion that at the base of the mantle there is an alternately interrupted layer consisting of giant continents. And they, in turn, could have formed as a result of the mixing of the rocks of the mantle itself with the substance of the core. But another possibility is that these areas could represent the bottom of ancient oceans. Notes are details. Further, the geological structure of the Earth continues with the core.
Core
The formation of the core is explained by the fact that in the early historical period of the Earth, substances with the highest density (iron and nickel) settled to the center and formed the core. It is the most dense part, representing the structure of the Earth. It is divided into a molten outer core (approximately 2200 km thick) and a solid inner core (approximately 2500 km in diameter). It makes up 16% of the total volume of the Earth and 32% of its total mass. Its radius is 3500 km. What happens inside the core is hardly imaginable - here the temperature is over 3000 ° C and colossal pressure.
Convection
The heat that was accumulated during the formation of the Earth is still being released from its depths as the core cools and radioactive elements decay. It does not come to the surface only due to the fact that there is a mantle, the rocks of which have excellent thermal insulation. But this heat sets the very substance of the mantle in motion - first, hot rocks rise up from the core, and then, being cooled by it, return again. This process is called convection. It results in volcanic eruptions and earthquakes.
A magnetic field
The molten iron in the outer core has a circulation that creates electrical currents that generate the Earth's magnetic field. It spreads into space and creates a magnetic shell around the Earth, which reflects the flows of the solar wind (charged particles ejected by the Sun) and protects living beings from deadly radiation.
Where is the data from
All information is obtained using various geophysical methods. On the surface of the Earth, seismologists (scientists who study the vibrations of the Earth) set up seismological stations, where any vibrations of the earth's crust are recorded. By observing the activity of seismic waves in different parts of the Earth, the most powerful computers reproduce a picture of what is happening in the depths of the planet in the same way that X-rays “shine through” the human body.
Finally
We only talked a little about what the structure of the Earth is. In fact, this issue can be studied for a very long time, because. it is full of nuances and features. For this purpose, there are seismologists. The rest is enough to have general information about its structure. But in no case should we forget that the planet Earth is our home, without which we would not exist. And it should be treated with love, respect and care.
Definition 2
Hydrosphere- the water shell of the planet's surface, consisting of all the water bodies that exist on Earth.
The thickness of this water shell is different in different areas. The average depth is $3.8$ km, and the maximum depth is $11$ km. The hydrosphere is a powerful geological force that carries out the cycle of both water and other substances.
Another new shell appears with the advent of life on Earth - this biosphere. The term was introduced E. Suessom ($1875$).
Definition 3
Biosphere- this is that part of the shells of the Earth in which various organisms live.
The boundaries of this shell are associated with the presence of conditions necessary for normal life, so its upper part is limited intensity of ultraviolet radiation, and the lower one with temperatures up to $100$ degrees.
Remark 3
Biosphere considered the highest ecosystem of the Earth, because it is a combination of all biogeocenoses.
The appearance of man on Earth led to the emergence of anthropogenic factors, which, with the development of civilization, intensified and led to the emergence of a specific shell - noosphere. This term was first introduced E. Leroy($1870-1954$) and T.Ya. de Chardin ($1881-1955$).
The noosphere is the highest stage in the evolution of the biosphere, and is closely related to the development of human society. This is the sphere of interaction between society and nature. Within the boundaries of this interaction, intelligent human activity becomes the determining factor.
Remark 4
Noosphere is part of biosphere, the development of which is directed the mind of man.
