Discovery of The Earth's Double Inner Core!
Scientists say they have gained new insight into what lies at the very centre of the Earth.
Research from China and the US suggests that the innermost core of our planet has another, distinct region at its centre.
The team believes that the structure of the iron crystals there is different from those found in the outer part of the inner core.
The findings are reported in the journal Nature Geoscience.
Without being able to drill into the heart of the Earth, its make-up is something of a mystery.
So instead, scientists use echoes generated by earthquakes to study the core, by analysing how they change as they travel through the different layers of our planet.
Prof Xiaodong Song, from the University of Illinois at Urbana-Champaign said: "The waves are bouncing back and forth from one side of the Earth to the other side of the Earth."
Prof Song and his colleagues in China say this data suggests that the Earth's inner core - a solid region that is about the size of the Moon - is made up of two parts.