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 bit about planet Earth
The velocity of the celestial body around the Sun is 29.765 km / s. It makes a full revolution in 365.24 sunny days.
Our planet Earth has one satellite. This is the moon. It is in the orbit of our planet at a distance of 384,400 km. Mars has two satellites, 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 mass and density
Its mass is 5.98 * 1024 kg, and the average density of the Earth is 5.52 g / cm 3 . At the same time, this indicator near the earth's crust is in the range of 2.71 g / cm 3 . It follows from this that the density of planet Earth increases significantly towards depth. This is due to the peculiarity of its structure.
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 / cm 3 . Its chemical composition resembles the terrestrial planets such as Venus and Mars and partially Mercury. Earth composition: iron - 32%, oxygen - 30%, silicon - 15%, magnesium - 14%, sulfur - 3%, nickel - 2%, calcium - 1.6% and aluminum - 1.5%. The remaining elements in the amount of about 1.2%.
Our planet is a blue space traveler
Finding the Earth near the Sun affects the presence of certain chemicals in both liquid and gaseous states. Thanks to this, the composition of the Earth is diverse, an atmosphere, a hydrosphere and a lithosphere are 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 planet in the solar system known today that has a hydrosphere. Water 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 the climatic conditions at different latitudes and forms the climate on the planet. It is represented by oceans, rivers and groundwaters. The solid part of our planet consists of sedimentary formations, a granite and basalt layer.
Earth structure and its structure
Earth, like the rest of the planet of the earth group, has a layered internal structure. At its center is the core.
This is followed by a mantle, which occupies a significant part of the planet’s volume, and then the
earth’s crust. Between themselves, the layers formed differ greatly in composition. Over the life of our planet, over 4.5 billion years, heavier rocks and elements under the influence of gravity penetrated farther and farther into the center of the Earth. Other elements, lighter, remained closer to its surface.
The complexity and inaccessibility of studying the subsoil
It is very difficult for man to penetrate deep into the Earth. One of the deepest wells 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.
We use 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. Every hour at different points on the Earth there are about ten oscillations of its surface. Based on the data obtained, thousands of seismic stations conduct research on the propagation of waves during an earthquake. These vibrations propagate in the same way as circles on the water from an abandoned object. When a wave penetrates into a denser layer, its speed changes dramatically. Using the data obtained, scientists were able to determine the boundaries of the inner shells of our planet. In the structure of the Earth there are three main layers.
Earth's crust and its properties
The upper shell of the Earth is the earth's crust. Its thickness can vary from 5 kilometers in the oceanic areas to 70 kilometers in the mountainous regions of the mainland. In relation to the whole planet, this shell is no thicker than an egg shell, and underground fire rages beneath it. Echoes of the deep processes occurring in the bowels of the Earth, which we observe in the form of volcanic eruptions and earthquakes, cause great damage.
The earth’s crust is the only layer that is accessible to people for life and full research. The structure of the earth's crust under the continents and oceans is different.
The continental crust occupies a much smaller surface area of ​​the earth, but has a more complex structure. It contains an external granite and lower basaltic layer under the sedimentary layer. In the continental crust, older breeds are found, whose age is almost two billion years.
The oceanic crust is thinner, only about five kilometers, and contains two layers: lower basalt and upper sedimentary. The age of oceanic rocks does not exceed 150 million years. Life can 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 quite sharply marked. It is called the Mokhorovich layer, and it can be found at a depth of about forty kilometers. The boundary of Mokhorovich consists mainly of solid basalts and silicates. The exception is some “lava pockets” that are in liquid form.
The thickness of the mantle is almost three thousand kilometers. The same layers are found on other planets. At this boundary, there is a clear increase in seismic velocities from 7.81 to 8.22 km / s. The mantle of the Earth 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 about the mantle formed?
At the beginning of the 20th century, the border of Mohorovic was intensively discussed. Some researchers believed that it was there that a metamorphic process occurs, in which rocks with high density are formed. Other scientists attributed the sharp increase in the speed of seismic waves to a change in the composition of the rocks from relatively light to heavier types.
Now this point of view is considered the main 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 occurrence, and it does not come to the surface.
Therefore, the basic information obtained by geochemical and geophysical methods. In general, reconstruction through existing sources is a very difficult task.
The mantle, receiving radiation from the center, is heated from 800 degrees above to 2000 degrees near the core. It is assumed, in fact, that the substance of the mantle is in continuous motion.
What is the density of the Earth in the mantle?
The density of the Earth within the mantle reaches about 5.9 g / cm 3 . Pressure increases with increasing depth and can reach 1.6 million atmospheres. On the issue of determining the temperature in the mantle, the opinions of scientists are ambiguous and quite contradictory, 1500-10000 degrees Celsius. These are the prevailing opinions in academia.
The closer to the center, the hotter
In the center of the Earth is the core. 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 fluid and electrical conductivity. It contains about 12% sulfur and 88% iron. At the boundary of the core and mantle, the Earth's density sharply increases and reaches about 9.5 g / cm 3 . At a depth of approximately 5100 km, its inner part is recognized, the radius of which is about 1260 kilometers, and its mass is 1.7% of the total mass of the planet.
The pressure in the center is so huge that the iron and nickel, which must be liquid, are in a solid state. According to scientific studies, the center of the Earth is a place with 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 temperature of such metals is equal to 1450-1500 degrees Celsius. Due to the gigantic pressure in the center, the mass and density of the Earth are quite huge. One cubic decimeter of matter weighs about twelve and a half kilograms. This is a unique and unique place where the density of the planet is much higher than in any other layer.
To reveal all the mechanisms of interaction within 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 the occurrence of earthquakes would become fully understood, which would make it possible to accurately prevent them. Today they are unpredictable and bring many sacrifices and destruction. Exact knowledge of the convection of currents and their interaction with the lithosphere may shed light on this problem. Therefore, future scientists have a long, interesting and useful work for all of humanity.