Journey To The Centre Of The Centre Of The Earth: Earth's Inner Core Has An Inner Core Of Its Own!

FORBES - The center of the Earth has long been a deep mystery to scientists and fertile ground for science fiction writers like the great Jules Verne.

Because man-made machines can’t penetrate into the inner core, researchers have to come up with novel ways to try to measure and study it. One such idea, used by a team of scientists from the University of Illinois and Nanjing University in China, has discovered that the inner core of the planet has an inner core of its own.

The team used earthquake-reading technology – seismic waves – to sound out the centre of the Earth, much like doctors use ultrasounds to see inside patients. What they found is that the Earth’s centre is not a solid ball of iron, as once thought, but a complex structure.

Inside the inner core, the scientists discovered another core, around half the diameter of the whole core. The iron crystals in the outer layer of the inner core are aligned directionally north to south. But in the inner-inner core, the iron crystals point roughly east-west.

Not only are the iron crystals aligned differently, but they behave differently as well, which could indicate that this inner-inner core is made of a different type of crystal.

“The fact that we have two regions that are distinctly different may tell us something about how the inner core has been evolving,” said  Xiaodong Song, a professor of geology at the University of Illinois.