What's inside the earth?

1. There are core, mantle and shell structures inside the earth, and hydrosphere, atmosphere and magnetic field outside the earth. The earth is the only known celestial body with life in the universe at present, and it is the home of millions of creatures, including human beings.

2. The core is the central part of the earth, located about 2900 kilometers below the surface. According to the propagation speed of seismic waves, the core can be divided into inner core and outer core, the outer core is liquid and the inner core is solid.

3. The core is mainly composed of iron and nickel. At present, many experts believe that the main substance in the earth's core may be iron-nickel alloy in crystal state.

However, the research team led by Dr. Blaj King of Russian physics and mathematics found in the experiment that when iron is heated to a molten state and the pressure of molten iron gradually rises to 654.38+ million atmospheres, the viscosity of molten iron will continue to increase, the crystal lattice in iron will be gradually destroyed, and its atomic structure will be irregularly arranged, that is, amorphous. ?

4. The maximum pressure of the core can reach about 3.7 million atmospheres, and the core temperature is about 5,000 degrees Celsius. Dr Blaj King speculates that with the increase of pressure and temperature, the viscosity of molten iron will continue to increase, and its amorphous characteristics will become more and more obvious. Therefore, the main substances in the core may be high viscosity, amorphous and iron-nickel components.

Extended data:

1, the earth's atmosphere is the outermost gas layer in the outer circle of the earth, surrounding the ocean and land. There is no exact upper limit of the atmosphere, and there are still thin gases and elementary particles at an altitude of 2000 ~ 16000 km. There is also a small amount of air in the ground, soil and some rocks, which can also be considered as a part of the atmosphere.

The main components of the earth's atmosphere are nitrogen, oxygen, argon, carbon dioxide and trace gases less than 0.04%. The total mass of gases in the earth's atmosphere is about 5.136×1021g, which is equivalent to 0.86% of the total mass of the earth.

Due to gravity, almost all gases are concentrated in the height range of 100 km above the ground, and 75% of the atmosphere is concentrated in the troposphere range from the ground to 10 km. According to the distribution characteristics of the atmosphere, it can be divided into stratosphere, mesosphere and thermosphere above troposphere.

2. The hydrosphere includes oceans, rivers, lakes, swamps, glaciers and groundwater. This is a continuous but irregular circle. Overlooking the earth from a height of tens of thousands of kilometers, we can see the white clouds formed by water vapor in the earth's atmosphere and the blue ocean covering most areas of the earth, making the earth a "blue planet".

The total mass of the earth's hydrosphere is 1.66× 10.24g, which is about 1.3600 of the total mass of the earth, and the mass of ocean water is about 35 times that of land water (including rivers, lakes, surface rock pores and soil). If the whole earth had no ups and downs of solid parts, the whole world would be covered by a water layer as deep as 2600 meters. The atmosphere and hydrosphere combine to form the fluid system on the surface.

3. Because there are minerals in the atmosphere, hydrosphere and surface of the earth, a natural environment suitable for living things has been formed under this suitable temperature condition on the earth. People usually refer to living things, including plants, animals and microorganisms. It is estimated that there are about 400,000 species of plants, about 165438+ 10,000 species of animals and at least 65438+ 10,000 species of microorganisms.

According to statistics, there are about 500-10 billion species of living things in geological history. However, during the long evolution of the earth, most of them have become extinct. Existing organisms live in the upper lithosphere, the lower atmosphere and the whole hydrosphere, forming a unique biosphere on earth, called biosphere. The biosphere is the only sphere on the earth among all the planets in the solar system.

4. For the earth's lithosphere, it is impossible to observe it directly except the surface morphology. It is mainly composed of the crust in the mantle circle and the top of the upper mantle, and extends from the solid earth surface down through the first discontinuity (Moho surface) shown by seismic waves at a distance of nearly 33 kilometers to the asthenosphere.

The thickness of lithosphere is uneven, with an average thickness of about 100 km. Because the lithosphere and its surface morphology are closely related to modern geophysics and geodynamics, the lithosphere is the most detailed and thorough part of the solid earth in modern geoscience.

Because the ocean floor occupies as much as two-thirds of the total area of the earth's surface, while the ocean basin accounts for about 45% of the total area of the ocean floor, with an average water depth of 4000 ~ 5000 meters, a large number of submarine volcanoes are distributed in the ocean basin, and vast submarine hills extend around it.

Therefore, the main surface morphology of the whole solid earth can be considered to be composed of ocean basins and continental platforms, and the study of them constitutes a "global structure" theory directly related to lithospheric structure and geodynamics.

5. In the upper mantle about 100 km below the earth's surface, there is an obvious low-velocity layer of seismic waves, which was first proposed by Gutenberg in 1926 and called asthenosphere. It is located in the upper part of the upper mantle, that is, layer B.

Below the seabed, it is located about 60 kilometers below the depth; In Chinese mainland, it is located below the depth of about 120km, with an average depth of about 60-250km. Modern observation and research have confirmed the existence of this asthenosphere. It is precisely because of this asthenosphere that the outer circle of the earth is distinguished from the inner circle of the earth.

6. Seismic waves belong to the mantle circle, but there is an obvious discontinuity (called Moho surface) about 33 kilometers below the ground, below the asthenosphere, until the interface about 2900 kilometers deep inside the earth. Because the outer core of the earth is liquid, the seismic S wave in the mantle cannot propagate through this interface in the outer core.

At this interface, the velocity of P-wave curve also drops sharply. This interface was discovered by Gutenberg in 19 14, so it is also called Gutenberg surface, which constitutes the interface between mantle sphere and outer core fluid sphere. The whole mantle consists of upper mantle (33 ~ 4 10 km), lower mantle D' layer (1000 ~ 2700 km) and lower mantle d "layer (2700 ~ 2900 km).

Geophysical research shows that there is a strong lateral inhomogeneity in D ′ layer, and its inhomogeneity is even equivalent to that in rock layer. It is not only a thermal boundary layer where the heat from the earth's core is transferred to the mantle, but also a chemical stratification different from the chemical composition of the mantle.

7. Below the mantle is the so-called exonuclear liquid sphere, which is located at a depth of about 2900-5 120 km below the ground. The whole outer core liquid circle may be basically composed of liquid with very low dynamic viscosity, and the depth of 2900 to 4980 kilometers is called E layer, which is completely composed of liquid. The depth layer of 4980-5 120 km is called F layer, which is a thin transition layer between the outer core liquid sphere and the solid inner core sphere.

8. The so-called solid inner circle is closest to the center of the eight circles of the earth, which is located at the center of the earth at 5 120-637 1 km, also known as G layer. According to the detection and study of seismic wave velocity, it is proved that G layer is a solid structure. The inner layer of the earth is uneven, with an average earth density of 5.5 1.5g/cm3, while the density of the earth's lithosphere is only 2.6 ~ 3.0g/cm3.

So the density inside the earth must be much larger, and with the increase of depth, the density also changes obviously. The temperature inside the earth rises with depth. According to recent estimates, the temperature at the depth of 100 km is 1300℃, the temperature at the distance of 300 km is 2000℃, the temperature at the boundary between the mantle and the outer core liquid sphere is about 4000℃, and the temperature at the center of the earth is above 6000℃.

References:

Baidu Encyclopedia-Earth