Despite being quite close to us, the Earth’s core is still a mysterious structure. We can divide it to the inner core and the outer core. We also now it’s mostly ironic and it’s responsible for the magnetic field of our planet. Let’s take a closer look at its functions and structure.
The Outer Core
The Earth’s structure is quite similar to onion’s. It is made of four layers, each has a different structure and plays a different role in the Earth’s geology. Two of the layers of Earth create a core.
The outer core lays about 3 thousand kilometers from the surface and it is the only liquid layer of the Earth. That is because it’s not under enough pressure to be solid. It is made mostly of iron, nickel, with the occurrence of sulfur and oxygen. Moreover, the temperature inside is extremely high- up to 6 thousand degrees Celcius! Due to the convection of fluid ferromagnetic substances, the Earth creates a magnetic field. This in turn leads to a stable atmosphere and conditions for life.
The Inner Core
The most inner of the layers of the Earth is the solid inner core. It is most probably a solid sphere with about a 1.2 thousand kilometers radius (70% of the Moon’s radius). It is as hot as the surface of the Sun (about 5505 degrees Celcius). Quite like the outer layer, it is made of iron and nickel. Interestingly, the study from 2015 suggested, that the inner core has two layers. The data collected showed that the crystals in the ‘inner layer’ are in an east-to-west direction. Those in the outer line up north to south. That implies there was a phenomenon that flipped the orientation of the core, turning the crystals in the ‘outer’ inner core. However, that hypothesis needs more studies.
Also read: The History of Life Series
We still don’t know a lot about our planet’s core. However, we can establish that its behavior is a key factor for life on our planet. First of all, the moving iron and nickel create a magnetic field. That field protects the layer from the solar wind and UV radiation. Therefore, it protects life on our planet from harmful particles. Moreover, the core’s radiating heat keeps the Earth’s surface warm. Sometimes people use that geothermal energy to warm their houses (for example in Iceland).
Mysteries of the Earth’s Core
The layers of Earth are just a few kilometers down from us, however, we know more about the Moon. The deepest human-made core, the Kola Superdeep Borehole, reaches only 12.2 kilometers into our planet. That’s not even halfway through the lithosphere (the outermost layer)!
- The Triassic Period (The Beginning of the Dinosaurs)
- The Jurassic Period (The Age of the Dinosaurs)
- The Cretaceous Period (The End of the Dinosaurs)
All studies of the Earth’s inner and outer core come from the seismic data. Another unknown is the periodic reversals of the Earth’s magnetic field. Even the temperatures given above were estimated by scientists. There is no way to go directly down to the core because of both the temperature and the pressure. However, the current state of knowledge is a result of numerous, creative studies. Soon, one more may unravel a lot of mysteries.
Study of the Layers of Earth
In the 1940s, scientists thought that its composition is no secret. They calculated the original balance of minerals on Earth and concluded, that the missing iron and nickel must be in the core. However, only 10 years later the gravity measurements proved them wrong. The core must be heavier and denser than originally thought, though we don’t know which elements occur inside. However, that may soon be revealed.
The asteroid Psyche might be a naked iron core floating in space. The 2022 Psyche Mission may give us some answers on the structure of the Earth’s core. Moreover, it will help us compare the iron cores of other solid planets and show their most common properties.
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