Earth is part of the solar system along with the rest of the planets and the Sun. It belongs to the class of stone solid planets, which are distinguished by high density and consist of rocks, in contrast to gas giants, which are large and relatively low density. At the same time, the composition of the planet determines the internal structure of the globe.
Main parameters of the planet
Before we find out which layers stand out in the structure of the globe, let's talk about the main parameters of our planet. The Earth is located at a distance from the Sun, approximately equal to 150 million km. The nearest celestial body is the natural satellite of the planet - the Moon, which is located at a distance of 384 thousand km. The Earth-Moon system is considered unique, as it is the only one where the planet has such a large satellite.
Earth mass is 5.98 x 1027 kg, approximate volume is 1.083 x 1027 cubic. see. The planet revolves around the Sun, as well as around its own axis, and has an inclination relative to the plane, which causes the change of seasons. Periodrotation around the axis is approximately 24 hours, around the Sun - a little more than 365 days.
Mysteries of the internal structure
Before the method of exploring the depths using seismic waves was invented, scientists could only make assumptions about how the Earth works inside. Over time, they developed a number of geophysical methods that made it possible to learn about some features of the structure of the planet. In particular, seismic waves, which are recorded as a result of earthquakes and movements of the earth's crust, have found wide application. In some cases, such waves are generated artificially in order to get acquainted with the situation at depth by the nature of their reflections.
It is worth noting that this method allows you to obtain data indirectly, since there is no way to directly get into the depths of the bowels. As a result, it was found that the planet consists of several layers that differ in temperature, composition and pressure. So, what is the internal structure of the globe?
Earth's crust
The upper solid shell of the planet is called the earth's crust. Its thickness varies from 5 to 90 km, depending on the type, of which there are 4. The average density of this layer is 2.7 g/cm3. The crust of the continental type has the greatest thickness, the thickness of which reaches 90 km under some mountain systems. They also distinguish between oceanic crust located under the ocean, the thickness of which reaches 10 km, transitional and riftogenic. Transitionaldiffers in that it is located on the border of the continental and oceanic crust. The rift crust occurs where there are mid-ocean ridges and is thin, only 2 km thick.
The crust of any type consists of rocks of 3 types - sedimentary, granite and bas alt, which differ in density, chemical composition and nature of origin.
The lower boundary of the crust is called the Moho boundary, after its discoverer named Mohorovicic. It separates the crust from the underlying layer and is characterized by a sharp change in the phase state of matter.
Robe
This layer follows the solid crust and is the largest - its volume is approximately 83% of the total volume of the planet. The mantle begins just after the Moho boundary and extends to a depth of 2900 km. This layer is further subdivided into the upper, middle and lower mantle. A feature of the upper layer is the presence of the asthenosphere - a special layer where the substance is in a state of low hardness. The presence of this viscous layer explains the movement of the continents. In addition, during volcanic eruptions, the liquid molten substance poured out by them comes from this particular area. The upper mantle ends at a depth of about 900 km, where the middle mantle begins.
Distinctive features of this layer are high temperatures and pressure, which increase with increasing depth. This determines the special state of the mantle substance. Despite the fact that in the depths of the rocks have a hightemperature, they are in a solid state due to high pressure.
Processes occurring in the mantle
The interior of the planet has a very high temperature, due to the fact that the process of thermonuclear reaction is continuously going on in the core. However, comfortable living conditions remain on the surface. This is possible due to the presence of a mantle, which has heat-insulating properties. Thus, the heat released by the core enters it. The heated matter rises, gradually cooling down, while colder matter sinks down from the upper layers of the mantle. This circulation is called convection, it occurs non-stop.
The structure of the globe: core (outer)
The central part of the planet is the core, which begins at a depth of about 2900 km, just after the mantle. At the same time, it is clearly divided into 2 layers - external and internal. The thickness of the outer layer is 2200 km.
The characteristic features of the outer layer of the core are the predominance of iron and nickel in the composition, in contrast to the compounds of iron and silicon, of which the mantle mainly consists. The substance in the outer core is in a liquid state of aggregation. The rotation of the planet causes the movement of the liquid substance of the core, due to which a powerful magnetic field is formed. Therefore, the outer core of the planet can be called the generator of the planet's magnetic field, which deflects dangerous types of cosmic radiation, thanks to which life could originate on the Earth's surface.
Inner core
Inside the liquid metal shell is a solid inner core, the diameter of which reaches 2.5 thousand km. At present, it is still not studied for certain, and there are disputes between scientists regarding the processes taking place in it. This is due to the difficulty of obtaining data and the possibility of using only indirect research methods.
It is known for certain that the temperature of the substance in the inner core is at least 6 thousand degrees, however, despite this, it is in a solid state. This is due to the very high pressure that prevents the substance from passing into a liquid state - in the inner core it is presumably equal to 3 million atm. Under such conditions, a special state of matter may arise - metallization, when even elements such as gases can acquire the properties of metals and become solid and dense.
As for the chemical composition, there is still debate in the research community about which elements make up the inner core. Some scientists suggest that the main components are iron and nickel, others that sulfur, silicon, and oxygen may also be among the components.
The ratio of elements in different layers
The earth's composition is very diverse - it contains almost all the elements of the periodic system, but their content in different layers is not uniform. So, the earth's crust has the lowest density, so it consists of the lightest elements. The very sameheavy elements are in the core in the center of the planet, at high temperature and pressure, providing the process of nuclear decay. This ratio formed over time - immediately after the formation of the planet, its composition was presumably more homogeneous.
In geography lessons, students may be asked to draw the structure of the globe. To cope with this task, you need to adhere to a certain sequence of layers (it is described in the article). If the sequence is broken, or one of the layers is missed, then the work will be done incorrectly. You can also see the sequence of layers in the photo presented to your attention in the article.
