What’s in the center of the Earth?

┬áThe book “Following the history of science” takes readers to travel into the center of the Earth, explore the structure of the globe.




Can we travel to the center of the Earth?


Currently, new drills only penetrate the Earth’s crust about 10 km. We can learn more about the center of the Earth through the study of the propagation of seismic waves, thereby “splitting” the layers that make up the Earth: seismic waves propagate at different speeds depending on their density. density and material of the medium it passes through.


Where did the Earth come from?


The place we live in is made up of an agglomeration of matter orbiting the Sun, itself made up of clouds of dust and gas ejected when a star explodes.


Due to the collisions and agglomeration of matter, the early Earth heated to 4,700 degrees Celsius. This molten mass cooled, heavy elements accumulated at the center to form the Earth’s core, the elements. light element floats to the surface.


Recipe for making a planet


90% of the Earth’s composition is made up of 8 elements: iron (32.1%), oxygen (30.1%), silicon (15.1%), sulfur (2.9%), nickel (1 0.8%), magnesium (13.9%), calcium (1.5%), aluminum (1.4%). The other 84 naturally occurring chemical elements make up only 1.5% of the Earth’s composition.


Center of the Earth


The center of the Earth is the core, made up mainly of iron and nickel. Inside is the inner core (solid), surrounded by the outer core (liquid). The pressure exerted by the Earth’s mass is the reason why the inner core remains in a solid state even though the temperature here reaches more than 6,000 degrees Celsius.




The mantle lies between the core and the Earth’s crust, extending to a depth of 2,900 km. The mantle makes up 80% of the Earth’s volume and 65% of the Earth’s mass.


The mantle has two layers as the lower mantle, starting at a depth of 700 km, the upper mantle is more flexible. Mantle movements (although very slow) are responsible for earthquakes and volcanic eruptions. Magma is formed from partial melting at several points in the mantle, especially near the nucleus.


The surface is floating


The crust and the surface part of the upper mantle (about 100 km deep) form the lithosphere, which is divided into tectonic plates. In the solid and brittle form, the tectonic plates “drift” on the more flexible lithosphere. This is why the continents drift away.


Is the Earth round?


The Earth is not perfectly round. Isaac Newton, in Principia mathematica (1687) and Christiaan Huygens in 1690 hypothesized that the Earth was flattened at the poles due to the centrifugal force produced by rotation. Geodetic calculations of the size of the Earth, together with observations from satellites, confirmed that assumption.


Depth bacteria can penetrate


Our planet is 4.7 billion years old. The depth where bacteria can still be found is 2.8 km. They survive by using radioactive uranium to convert water into heat.