What does the earth consist of?
The third planet of the solar system was formed about 4.5 million years ago from pieces and fragments of cosmic bodies, dust and gas. For a long time, it was subjected to surface bombardment by meteorites, whose energy did not have time to free themselves from the outside and heated the planet from the inside. This, together with gravity processes, led to the formation of liquid masses, which were separated from the solid parts. Thus, shells were formed more dense inside and less - outside. While cooling, the planet released a huge amount of gases, which later became the material for the formation of the atmosphere. Such is the theory of the formation of the planet Earth.
What does planet earth consist of
For the first time, a proposal to divide the structure of the Earth into concentric circles was made 120 years ago by the Austrian scientist Edward Süss. For many years of research, it was possible to identify three main components of the structure of the earth: the core, the mantle and the crust of the earth. Moreover, only the last part is available for research, and the theory of the structure of the core and mantle is only conjectural today.
The thickness of the earth's crust is different and reaches 30-40 kilometers below the continents and only 7-10 - on the ocean floor. The minimum known crustal thickness near Easter Island is 5km, and the maximum thickness in the Himalayas is 90km.
By mathematical calculations, scientists managed to find out that the radius of the planet's core is 3471km, and the thickness of the mantle is 2888km. Later, the core was supposedly divided into two parts: one of them, the inner one, has a density of 12.5 g / cm2, radius is 1225km and is in a solid state, the other less dense - 10g / cm2- liquid. Having a high temperature, the core warms up a substance similar to volcanic lava, which causes it to move towards a colder mantle.
The mantle occupies 82% of the volume of the Earth, has a density of 5g / cm2and also divided conditionally into two parts: the lower and upper. The lower border of the core (about 670 km deep) has something greater density, the upper one originates at a depth of 420 km and ends under the earth's crust. The upper layer of the mantle together with the Earth's crust have a common name - the lithosphere - shell, consisting of lithospheric plates. Lithospheric plates, in turn, are the "foundation" of the continents.These are the modern concepts of what the Earth consists of.
The oceanic crust is formed from the rocks of the mantle, which stand out from its upper layer and enter through cracks in the crust up to the water, freeze, turning into a solid basalt layer.
The continental cortex consists of several layers. Its surface is formed by sandstones, limestones, clays. The presence of the next layer consisting of granites and rocks, modified under the influence of high temperatures and pressure; makes it different from the oceanic crust. The age of these structures is also different. Scientists “give” 150-170 million to the oceanic crust. years, whereas continental - more than 3 billion years.
A greater idea of what constitutes the planet Earth, gives its chemical composition. The most common in the crust of 46 chemical elements, seven of which are more than 97% of the mass. Including:
- oxygen - 49.13%;
- silicon - 26%;
- aluminum - 7.45%;
- iron - 4.20;
- calcium - 3.25%;
- sodium - 2.40%
- magnesium - 2.35%.
Investigating volcanic lava, scientists have concluded that the mantle mainly consists of peridotite. This breed contains 80% olivine and 20% pyroxene.
Temperature and pressure
Temperature and pressure have a significant impact on the formation of compounds, which subsequently are what constitutes the Earth.
The energy of the sun is able to penetrate through the crust to a certain depth. Starting with a few centimeters, in places this depth reaches two meters. Such a difference is due to the depth of the isothermal horizon - a layer with a constant temperature. Below this layer, the temperature rises on average by 1 ° C every 33 meters.
The mantle layer consists mainly of heavy minerals. The temperature reaches 250 ° C, which allows it to be in a liquid state. But with increasing depth, the pressure rises to 1.3 million. atmospheres, which causes the mantle to crystallize.
The center of the core has a temperature of 10,000 ° C and a pressure of 3 million atmospheres.
What is the doctrine
How to learn to dance in a nightclub
Canned sterilization formula
How to please the girl
How to make a script
How to teach children to read