Following clues left by the seismic waves, a team of scientists from China and the United States revealed that there’s a smaller inner core within the Earth’s actual core. So the theory according to which the Earth has four layers: the crust, the mantle, the outer core and the inner core has been in-firmed.

“The inner core can be read like a tree’s rings. Even though the inner core is small, smaller than the moon, it has some really interesting features. It may tell us about how our planet formed its history, and other dynamic processes of the Earth. It shapes our understanding of what’s going on deep with the Earth,”

Xiaodong Song, who is part of the research team and professor at the Department of Geology at the University of Illinois, said.

The inner core had been initially believed to be a hard ball of iron. But reportedly things don’t stop here. It appears there’s a hidden nucleus, about half the diameter of its outer core, containing iron crystals. Now these iron crystals align east-west. However the iron crystals of the outer shell align north-south. This may mean that the outer core iron crystals may have a different nature than the inner core ones, scientists explained. This difference might hold the answer regarding the evolution of our planet, the research team explained.

Using seismic waves from earthquakes in order to scan below the Earth’s surface, the team, relying on the fact that seismic waves have the habit of bouncing back and forth from one side of the Earth to the other side of the Earth, managed to understand how things are happening at the very core of our planet.

Differences regarding the way in which seismic waves travel between the outer parts of the inner core and the inner parts has been tackled before, but the assumption according to which the alignment of crystalline iron that makes up this region is completely lopsided compared to the outer part is completely new.

This definitely proves the fact that the Earth has been through some radically dramatic changes throughout its history of development so as to make the orientation of the core flip the way it did.