The structure of the Earth has been a topic of study and fascination for scientists for centuries. Over time, researchers have developed a deeper understanding of the planet's interior and its composition. However, a recent study by seismologists from The Australian National University (ANU) has revealed the existence of a previously unknown layer within the Earth's inner core.
For many years, it was believed that the Earth's structure consisted of four layers: the crust, mantle, outer core, and inner core. However, the latest research published in Nature Communications suggests that there is a fifth layer. Using seismic waves caused by earthquakes, the scientists were able to observe a mystery metal ball within the Earth's deep core, providing new insights into the planet's structure.
The inner core, which was discovered in the 1930s, is a solid ball of iron and nickel with a diameter of about 1,500 miles (2,440 km). However, the recent study has revealed that there is a distinct structure within the inner core. This structure is a wickedly hot innermost solid ball of iron and nickel, about 800 miles (1,350 km) wide.
The discovery of this new layer is significant because it provides new insights into the planet's formation and evolution. The Earth's inner core accounts for less than 1% of the planet's volume, but it is a time capsule of the planet's history. As the inner core grows, it releases latent heat and light elements that drive the convection of the liquid outer core. This, in turn, maintains the geodynamo that generates the Earth's magnetic field.
The study was made possible by the unprecedented expansion of the global seismic networks, particularly the dense networks in the contiguous US, the Alaskan peninsula, and over the European Alps. The researchers analyzed digital records of ground motion, known as seismograms, from large earthquakes in the last decade.
Observational seismologist Thanh-Son Pham of ANU, who led the study, said, "We may know more about the surface of other distant celestial bodies than the deep interior of our planet." He added, "Earth's inner core is a time capsule of our planet's history, and understanding its structure and behavior is essential for understanding the planet's formation and evolution."
The discovery of the new layer in the Earth's inner core opens up new avenues for research and could lead to a better understanding of the planet's dynamics. As technology continues to advance, it is likely that scientists will uncover even more secrets hidden within the Earth's interior.