Earth is part of the solar system, located at a distance of 149.8 million kilometers from the Sun and is the fifth largest among other planets.
A little about planet Earth
The speed of revolution of a celestial body around the Sun is 29.765 km/s. It makes a complete rotation in 365.24 solar days.
Our planet Earth has one satellite. This is the moon. It is in orbit of our planet at a distance of 384,400 km. Mars has two moons, and Jupiter has sixty-seven. The average radius of our planet is 6371 km, while it looks like an ellipsoid, slightly flattened at the poles and elongated along the equator.
Earth's mass and density
Its mass is 5.981024 kg, and the average density of the Earth is 5.52 g/cm3. At the same time, this indicator near the earth's crust is within 2.71 g/cm3. From this it follows that the density of the planet Earth increases significantly in the direction of depth. This is due to the nature of herbuildings.
For the first time, the average density of the Earth was determined by I. Newton, who calculated it in the amount of 5-6 g/cm3. Its chemical composition is similar to the terrestrial planets such as Venus and Mars and partly Mercury. The composition of the Earth: iron - 32%, oxygen - 30%, silicon - 15%, magnesium - 14%, sulfur - 3%, nickel - 2%, calcium - 1.6% and aluminum - 1.5%. The remaining items add up to about 1.2%.
Our planet is a blue traveler in space
The location of the Earth near the Sun affects the presence of certain chemicals in both liquid and gaseous states. Due to this, the composition of the Earth is diverse, the atmosphere, hydrosphere and lithosphere were formed. The atmosphere mainly consists of a mixture of gases: nitrogen and oxygen 78% and 21% respectively. As well as carbon dioxide - 1.6% and a negligible amount of inert gases such as helium, neon, xenon and others.
The hydrosphere of our planet consists of water and occupies 3/4 of its surface. Earth is the only known planet in the solar system today that has a hydrosphere. Water has played a decisive role in the process of the emergence of life on Earth. Due to its circulation and high heat capacity, the hydrosphere balances climatic conditions at different latitudes and forms the climate on the planet. It is represented by oceans, rivers and underground waters. The solid part of our planet consists of sedimentary formations, granite and bas alt layers.
The structure of the Earth and its structure
The Earth, like the rest of the planets of the terrestrial group, has a layered internal structure. In herthe center is the core.
Followed by the mantle, which occupies a significant part of the planet's volume, and then the earth's crust. Between themselves, the formed layers differ greatly in their composition. During the existence of our planet, over 4.5 billion years, heavier rocks and elements under the influence of gravity penetrated further and further into the center of the Earth. Other elements, lighter, remained closer to its surface.
Difficulty and inaccessibility of subsurface exploration
It is very difficult for a person to penetrate deep into the Earth. One of the deepest wells was drilled on the Kola Peninsula. Its depth reaches 12 kilometers.
The distance from the surface to the center of the planet is more than 6300 kilometers.
Using indirect research tools
Because of this, the bowels of our planet, located at a considerable depth, are analyzed according to the results of seismic exploration. About ten oscillations of its surface are observed every hour at different points on the Earth. Based on the data obtained, thousands of seismic stations are conducting a study of the propagation of waves during an earthquake. These vibrations propagate in exactly the same way as circles on the water from a thrown object. When a wave penetrates into a more compacted layer, its speed changes dramatically. Using the data obtained, scientists were able to determine the boundaries of the inner shells of our planet. Three main layers are distinguished in the structure of the Earth.
Earth's crust and its properties
TopThe Earth's shell is the earth's crust. Its thickness can vary from 5 kilometers in oceanic areas to 70 kilometers in mountainous areas of the mainland. In relation to the entire planet, this shell is no thicker than an eggshell, and underground fire rages under it. Echoes of deep processes occurring in the bowels of the Earth, which we observe in the form of volcanic eruptions and earthquakes, cause great destruction.
The Earth's crust is the only layer that is available to people for life and full-fledged research. The structure of the earth's crust under the continents and oceans is different.
The continental crust occupies a much smaller area of the earth's surface, but has a more complex structure. It contains under the sedimentary layer the outer granite and lower bas alt layers. Older rocks are found in the continental crust, almost two billion years old.
Oceanic crust is thinner, only about five kilometers, and contains two layers: lower bas altic and upper sedimentary. The age of oceanic rocks does not exceed 150 million years. Life could exist in this layer.
The Mantle and what we know about it
Under the crust lies a layer called the mantle. The boundary between it and the bark is rather sharply marked. It is called the Mohorovich layer, and it can be found at a depth of about forty kilometers. The Mohorovich boundary consists mainly of solid bas alts and silicates. The exception is some "lava pockets", which are in liquid form.
The thickness of the mantle is almost three thousand kilometers. Similar layers have been found on other planets. At this boundary, there is a clear increase in seismic velocities from 7.81 to 8.22 km/s. The Earth's mantle is divided into upper and lower components. The boundary between these geospheres is the Galicin layer, which is located at a depth of about 670 km.
How was knowledge of the mantle formed?
At the beginning of the 20th century, the Mohorovic border was intensively discussed. Some researchers believed that it was there that the metamorphic process takes place, during which rocks with high density are formed. Other scientists attributed the sharp increase in the speed of seismic waves to a change in rock composition from relatively light to heavier types.
Now this point of view is considered the main one in understanding and methods of studying the processes occurring inside the planet. The Earth's mantle itself is not directly accessible for direct research due to its deep location, and it does not come to the surface.
Therefore, the main information was obtained by geochemical and geophysical methods. In general, reconstruction through the available sources is a very difficult task.
The mantle, which receives radiation from the center, is heated from 800 degrees at the top to 2000 degrees near the core. It is assumed, in fact, that the substance of the mantle is in constant motion.
What is the density of the Earth in the mantle region?
The density of the Earth within the mantle reaches about 5.9 g/cm3. Pressuregrows with increasing depth and can reach 1.6 million atmospheres. In the matter of determining the temperature in the mantle, the opinions of scientists are not unambiguous and rather contradictory, 1500-10000 degrees Celsius. These are the prevailing opinions in scientific circles.
The closer to the center, the hotter
A core is placed in the center of the Earth. Its upper part is located at a depth of 2900 kilometers from the surface (outer core) and makes up about 30% of the total mass of the planet. This layer has the properties of a viscous liquid and electrical conductivity. Contains about 12% sulfur and 88% iron. At the boundary of the core and mantle, the density of the Earth increases sharply and reaches about 9.5 g/cm3. At a depth of approximately 5100 km, its inner part is recognized, the radius of which is about 1260 kilometers, and the mass is 1.7% of the total mass of the planet.
The pressure at the center is so huge that iron and nickel, which should be liquid, are in a solid state. According to scientific studies, the center of the Earth is a place with super extreme conditions with a pressure of 3.5 million atmospheres and temperatures above 6000 degrees.
In this regard, the iron-nickel alloy does not go into a liquid state, despite the fact that the melting point of such metals is 1450-1500 degrees Celsius. Due to the gigantic pressure at the center, the mass and density of the Earth are quite enormous. One cubic decimeter of a substance weighs about twelve and a half kilograms. This is a unique and the only place where the density of the planet is significantly higher than in any other of itslayer.
To reveal all the mechanisms of interaction inside the Earth would be not only interesting, but also useful. We would understand the formation of various minerals and their location. Perhaps, the mechanism of earthquake occurrence would become fully understood, which would make it possible to accurately warn them. Today they are unpredictable and bring a lot of victims and destruction. Accurate knowledge of convection flows and their interaction with the lithosphere may shed light on this problem. Therefore, future scientists have a long, interesting and useful work for all mankind.
