Scientists have found the core…of the Earth’s core  

It is only 1% of the volume of the planet

The interior of our planet is a puzzle to scientists to this day, as it consists of a series of layers from the crust to the core. Now, after 20 years of research, a new analysis has shown that Earth’s inner core has its own core, a dense ball of iron and nickel at the center of the planet that makes up just 1% of Earth’s volume.

Studying the 1,227-kilometer-diameter inner core is not easy, and scientists must rely on seismic waves that travel through the planet’s interior, changing in intensity and direction as they encounter masses of different densities.

So 20 years ago, scientists recognized the presence of an inner core within the nucleus, while other studies that followed supported its existence. But further study of it was difficult because of the multiple layers. Advances in technology and global seismic station coverage allowed them to separate the inner core data from these records.

This study used the ever-expanding global network of seismographs to identify some of the most important seismic events individually.

By combining data from seismic waves, scientists were able to amplify the signals, effectively increasing the resolution of what we see inside the Earth. The different times at which the seismic waves were detected revealed the presence of another core within the Earth’s inner core, no larger than 650 kilometers in diameter, which is composed of dense iron.

The study means that we now have enough evidence for the existence of an inner core of the nucleus, and future studies can focus on tracing the boundary between it and the outer core.

The findings are the result of an unprecedented amount of digital waveform data and will hopefully inspire further research into existing seismic data that will reveal hidden clues about the Earth’s interior.

The study was published in Nature Communications .