Thanks to earthquakes, scientists discover “land within the earth”.

In his classic novel “Journey to the Center of the Earth”, published in 1864, Jules Verne tells the story of adventurers who go underground through a volcano in Iceland, discover a vast world inhabited by prehistoric creatures and explore the inner structure of the planet. But the real center of the earth is unrelated to this fantasy, and more interesting.

Scientists said on Tuesday that a detailed study of the planet’s depths, based on the movement of seismic waves from large earthquakes, confirmed the presence of a distinct and well-defined structure in the planet’s inner core. The discovered system is a raging solid ball of iron and nickel 1,350 km in diameter. The diameter of the earth is about 12,750 km. The inner structure consists of four layers: a rocky crust from the outside, then a rocky crust, followed by a volcanic outer core, and then a solid inner core.

This metallic inner core, approximately 2,440 kilometers in diameter, was discovered in the 1930s based on seismic waves traveling through the Earth. In 2002 scientists hypothesized that a deep region, separated from the rest, was hidden within this inner core, similar to a Russian matryoshka doll.

After the improvement of earthquake monitoring methods, it became possible to confirm this assumption. Earthquakes emit waves that travel across the planet and the changing shape of these waves can reveal features of its internal structure. So far, scientists have determined that these waves can bounce from one end of the Earth to the other and back twice.

The new study focused on 200 earthquake waves with magnitudes greater than six that bounced around the planet like ping-pong balls up to five times. “We probably know more about the surface of other distant celestial bodies than we do about the deep interior of our planet,” said Tan-Soon Baum of the Australian National University in Canberra, lead author of the study published in the journal Nature Communications.

“We analyzed digital records of ground motions, known as aftershocks, after massive earthquakes in the last decade. Our study was made possible by the unprecedented expansion of seismological networks around the world, especially in the United States, the Alaskan Peninsula, and the European Alps,” Baum added.

The outer shell and the newly discovered spherical body at the inner core are hot enough to melt together, but they are a mixture of iron and nickel, and form the enormous pressure center at the center of the Earth. A solid state.

“I like to think of the inner core as a planet within a planet,” said Hrvoje Tcalcic, a geophysicist at the Australian National University and co-author of the study.

Tkalcic added, “If the Earth were somehow stripped of its mantle and liquid outer core, the inner core would be as bright as a star. Its temperature is estimated at 5,500 degrees Celsius to six thousand degrees Celsius, similar to the surface temperature of the Sun.” Baum said that the transition from the outer part of the core of the Earth’s interior to the inner spherical body appears to be a gradual transition rather than a transition between clear and dividing boundaries.

Researchers were able to distinguish between the two regions due to the different behavior of seismic waves.