Earth is part of the solar system, along with other planets and the sun. It belongs to the class of stone hard planets, characterized by high density and consisting of rocks, in contrast to gas giants, which are large and relatively low in density. Moreover, the composition of the planet determines the internal structure of the globe.
The main parameters of the planet
Before you know what 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 of about 150 million km from the Sun. The nearest celestial body is the planet’s natural satellite - 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.
The earth's mass is 5.98 x 10 27 kg, the approximate volume is 1.083 x 10 27 cubic meters. see. The planet revolves around the Sun, as well as around its own axis, and has an inclination relative to the plane, which causes a change in the seasons. The period of revolution 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 bowels using seismic waves was invented, scientists could only make assumptions about how the Earth is arranged 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, are widely used. In some cases, such waves are generated artificially in order to familiarize themselves with the situation at a 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 hard 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 continental-type crust has the greatest thickness, the thickness of which reaches 90 km under some mountain systems. Also distinguish the oceanic crust located under the ocean, the thickness of which reaches 10 km, transitional and riftogenic. Transitional is different in that it is located on the border of the continental and oceanic crust. The riftogenic crust is found where there are mid-ocean ridges, and is notable for its small thickness, which reaches only 2 km.
Any type of bark consists of 3 types of rocks - sedimentary, granite and basalt, which differ in density, chemical composition and nature of origin.
The lower boundary of the cortex is called the Moho border, in honor of its discoverer by the name of Mokhorovich. It separates the cortex from the underlying layer and is characterized by a sharp change in the phase state of the substance.
Mantle
This layer follows the hard crust and is the largest - its volume is approximately 83% of the total planet. The mantle begins immediately after the border of Moho and extends to a depth of 2900 km. This layer is further divided into 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, molten liquid poured by them comes from this area. The upper mantle ends at a depth of approximately 900 km, where the middle begins.
Distinctive features of this layer can be called high temperatures and pressures, which increase with increasing depth. This determines the special state of the mantle substance. Despite the fact that they have a high temperature in the depths of the rock, they are in a solid state due to the influence of high pressure.
Processes occurring in the mantle
The bowels of the planet have a very high temperature, due to the fact that the process of thermonuclear reaction continuously occurs in the nucleus. 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 substance rises, gradually cooling, while colder matter plunges down from the upper layers of the mantle. This cycle is called convection, it occurs non-stop.
The structure of the globe: core (external)
The central part of the planet is a core that begins at a depth of about 2900 km, immediately 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, unlike 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 matter of the nucleus, due to which a powerful magnetic field is formed. Therefore, the outer core of the planet can be called the generator of the magnetic field of the planet, which deflects dangerous forms of cosmic radiation, so life could be born on the surface of the Earth .
Inner core
Inside the liquid metal shell is a solid inner core, the diameter of which reaches 2.5 thousand km. At present, it has not yet been thoroughly studied, 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 a substance in the inner core is at least 6 thousand degrees, however, despite this, it is in a solid state. This is explained by a very high pressure, which prevents the substance from becoming liquid - in the inner core it is supposedly equal to 3 million atm. Under such conditions, a special state of a substance — metallization — may occur, when even elements such as gases can acquire the properties of metals and become solid and dense.
As for the chemical composition, the research environment is still debating about which elements make up the inner core. Some scientists suggest that the main components are iron and nickel, while others - that sulfur, silicon, and oxygen can also be among the components.
The ratio of elements in different layers
The earth composition is very diverse - it contains almost all the elements of the periodic system, but their content in different layers is heterogeneous. So, the earth's crust has the lowest density, so it consists of the lightest elements. The heaviest elements are located 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 supposedly more homogeneous.
In geography classes, students can 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 missing, then the work will be performed incorrectly. You can also see the sequence of arrangement of layers in the photos presented to your attention in the article.