The Earth – the birthplace and nurturer of life – has long intrigued humans about its internal structure. Although we live only on the thin outer crust, deep below are complex and mysterious geological layers. So what is the composition of the Earth? Let's explore the "heart" of this planet through each layer in more detail.
1. Geological structure: How many layers does the Earth have?
The Earth is divided into four main layers, stacked from outside in: the crust, the mantle, the outer core, and the inner core.
• The Earth's crust (Crust) – the "foundation" of life
This is the outermost layer, and the part where humans live and exploit resources. The crust is surprisingly thin compared to the entire depth of the planet – only about 5 km below the ocean and up to 70 km below the continents.
It is mainly composed of silicates, especially aluminum silicate, potassium silicate and sodium silicate. It also contains elements such as calcium, magnesium and oxygen.
Illustration photo.
Fun fact: The Earth's crust is divided into two types – oceanic crust (thinner, mostly basalt) and continental crust (thicker, rich in granite and minerals).
• Mantle – giant “magma sea”
Just below the crust is the mantle – which makes up 84% of the Earth’s volume and is about 2,900 km thick. Although the material here is solid, because of the high temperature and pressure, it can move very slowly, like plastic.
The main constituents are magnesium- and iron-rich silicates, such as olivine and pyroxene.
This is where convection occurs – the convection of magma – which helps explain the movement of tectonic plates on the Earth's surface.
• Outer Core – the origin of the Earth's magnetic field
This layer is about 2,200 km thick, lies deeper than the mantle and is completely liquid, consisting mainly of molten iron and nickel.
The turbulent motion of liquid metal in the outer core creates the Earth's magnetic field, which protects the planet from solar radiation and helps keep life – including humans – safe.
• Inner Core – the “solid heart” is hotter than a steel furnace
The Earth’s core lies about 6,371 km deep and has a radius of about 1,200 km. Although temperatures can reach 5,700°C – nearly as high as the surface of the sun – the inner core is solid, due to the immense pressure that compresses the metal.
Main ingredients: pure iron, with a small amount of nickel and other light elements.
2. Not just rocks and soil – the Earth also has many “invisible layers”
In addition to its internal geographical structure, the Earth is covered by other important "layers" that create conditions for life to exist:
• Atmosphere
A thin layer of gas surrounding the planet, divided into layers such as troposphere, stratosphere, mesosphere and thermosphere.
Main components: 78% nitrogen, 21% oxygen, and the rest is carbon dioxide, water vapor, argon...
The atmosphere not only helps us breathe, but also retains heat, blocks ultraviolet rays, and creates weather phenomena.
• Hydrosphere
All the water on Earth – from oceans, rivers, lakes, to ice and groundwater. The hydrosphere covers about 71% of the Earth's surface.
• Biosphere
Including all living organisms – from bacteria underground to birds flying in the sky, and of course humans. The biosphere spans parts of the Earth's crust, hydrosphere, and atmosphere.
Conclude
Although we can only see a small part of our planet, the Earth is actually a giant and complex living machine. With its many layers – from a thin rocky crust to a blazing hot iron core, and “invisible” layers such as the atmosphere, hydrosphere and biosphere, the Earth is unique, the only planet known to be able to support life.
Understanding the makeup of the Earth not only helps us love the place we live, but is also key to protecting it for the future.
Source: https://doanhnghiepvn.vn/cong-nghe/thanh-phan-cau-tao-cua-trai-dat-gom-nhung-gi-kham-pha-ben-trong-hanh-tinh-xanh-cua-chung-ta/20250425020729640
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