The Earth consists of multiple layers of metallic and rocky materials. Beneath the thick layers of lighter rock near the top or the surface is heavier rock. Under the heavy rock, there are rocks that contain metal, and the amount of metal that makes up these rocks is increasing the more you go towards the center. The chief metals found in this area of the Earth are iron and nickel.
While we cannot see into the interior of the Earth and we do also don’t have any vehicle capable of getting us to the center, we do have some ways of finding out more about it. One way of learning more about the core is by observing the effect of the Earth’s gravity on the other planets and then calculating the Earth’s weight based on the effect. Once we do the calculations, we will find out that that the planet is far heavier than what the rocks on the surface weigh. Therefore, the Earth must have a heavy inner core, and it could also be the heaviest part of the planet. The weight of the inner core is attributed to iron-nickel material that makes up the majority of its contents. In addition, the iron-nickel portion of the inner core is believed to be about 1,200 kilometers in radius.
The reason scientists or researchers think that iron and nickel make up most of the Earth’s core is that most of the meteorites that fell on Earth are primarily made of these two metals. You may be wondering, what is the true connection between the Earth’s core and a meteorite that did not even originate from Earth?
The answer is that meteorites are believed to be fragments of a minor planet. These minor planets are said to have been created at the same time as the planets on our solar system like Jupiter, Saturn, and Mars, but they have not formed into major planets because they lack certain materials needed to be one. According to research, all planets contain the same materials, but they are only in different proportions, which is why some planets have more gas or air while others have more land. Since we know that our lithosphere (the upper rock layers that extend down to a depth of approximately 200 kilometers) does not contain high proportions of iron and nickel that are found in meteorites, making scientists assume that these materials must be packed or condensed closely in the Earth’s inner core.
What is the Mantle?
There is a layer on the Earth that is placed between the Earth’s crust and core, and this layer is called the mantle. The mantle is the thickest layer on Earth, as it has a depth of 2,890 kilometers, while the crust is only 5 to 70 kilometers.
This layer is usually divided into two, which are the upper mantle and the lower mantle. The upper mantle is positioned right beneath the Earth’s crust, and its materials consist of pyroxene, olivine, calcium oxide minerals, and aluminum oxide minerals. The lower mantle is thickest of the two parts, and it is made up of bridgmanite, calcium-silicate perovskite, and ferropericlase.
Deepest Artificial Point on Earth
Unfortunately, humans have not yet reached the mantle, but the deepest that we have drilled on the ground is about 12 kilometers, and this was done when the Soviet Union tried to drill as deep as possible on the ground located in the Kola Peninsula, Russia. The drilling for the site that will eventually be known as the Kola Superdeep Borehole started on May 24, 1970, using a heavy drill vehicle called the Uralmash-4E. The deepest point made by the members of the project has the designation name SG-3 and was achieved in 1989, which was 19 years after the drilling began. The Soviet government wanted to go deeper than 12 kilometers, but because the temperature in the deepest parts of the hole was rising and is considered dangerous for humans, with the deepest having a temperature of 180 degrees Celsius, the project had to be stopped in 1992.
There were plans to develop a research team that aimed to build a vehicle capable of normalizing interior temperature, but when the Soviet Union was dissolved in 1995, the Kola Superdeep Borehole project was abandoned entirely. What remains of the location today are the ruins of a facility where research on the materials in the deepest parts of the crust was conducted, and the borehole welded shut to prevent trespasser or sightseers from getting inside. It is believed that the facility remained intact during the late 90s, but it was subsequently demolished in the late 2000s or the early 2010s. There are currently no plans on reviving the project, as the conditions of the hole were not monitored since 1995, and it may now be unsafe to drill deeper into the hole. Despite the advancement in drilling technology in the present time, there is still no recent drilling project that was able to match what the Kola Superdeep Borehole project members accomplished in 1989.
Structure of the Earth (Wikipedia)
- How much is the Earth flattened at the Poles?
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- What is the weight of the planet Earth? Is it constant or increasing?
- Is there any physical evidence that asteroids struck our planet in the past?
- Why aren’t people at the equator thrown off into space by centrifugal force since the Earth is rotating at a high speed?