Scientists Find Earth's Inner Core has an Inner Core

Posted on February 15, 2015

There appears to be more to Earth's inner core than previously thought. Researchers at the University of Illinois and Nanjing University in China have determined that there is a mystery material at our planet's inner core. The researchers say they founded a distinct inner-inner core in the Earth using seismic waves.

Xiaodong Song, a professor of geology at the University of Illinois, says in a statement, "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 inside the Earth."

Determining what is at the core of the Earth isn't easy even using seismic waves. As Discovery explains these waves have to travel back through the planet after passing through Earth's core.

The Earth's core was once thought to be a solid ball of iron but is now known to have some complex structural properties. The researchers say the inner-inner core they found is about half the diameter of the whole inner core. They also found that the iron crystals in inner-inner core point east-west unlike the iron crystals in the outer layer of the inner core which point north-south. The researchers also found that iron crystals in the inner-inner core behave differently than the iron crystals in the Earth's inner core. The researchers say these means the inner-inner core could be made up of different crystals or the material may be in a different phase.

Song says, "The fact that we have two regions that are distinctly different may tell us something about how the inner core has been evolving. For example, over the history of the earth, the inner core might have had a very dramatic change in its deformation regime. It might hold the key to how the planet has evolved. We are right in the center – literally, the center of the Earth.'

A research paper on the inner part of Earth's inner core can be found here in the journal, Nature Geoscience.

EARTH