Jules Verne, the science fiction author who wrote the novel Journey to the Center of the Earth, painted in his work of fiction a picture of an Earth with an entirely different world at its center.
Although scientists have established a more simplistic planet that does not have a prehistoric land in its interior but is rather made up of three major layers, the crust, the mantle and the core, findings of a new study have revealed that the Earth's inner core is actually more complex than it was previously thought.
For the new study which was published in the Nature Geoscience on Feb. 9, Tao Wang, from the School of Earth Sciences and Engineering at the Nanjing University in China, and colleagues used seismic waves, echoes generated by earthquakes, to study the Earth's core much like the way doctors use ultrasound to see what is inside of their patients.
Wang and colleagues analyzed how these seismic waves change as they travel through the different layers of the planet and in the process made a surprising discovery. Using the seismic wave data, the researchers found two distinct parts in the Earth's inner core. The outer layer had iron crystals that are aligned north to south while the inner layer pointed east to west.
"Our findings are consistent with seismic anisotropy in the innermost inner core that has a fast axis near the equatorial plane through Central America and Southeast Asia, in contrast to the north-south alignment of anisotropy in the outer inner core," Wang and colleagues wrote.
The iron crystals in the Earth's inner-inner core likewise exhibit different behavior compared with their counterparts in the outer-inner core suggesting that these may be composed of a different type of crystal or were in a different phase of matter.
The researchers' findings suggest that something may have happened during the evolution of the Earth's core that resulted in its iron crystals flipping their alignment. Study researcher Xiaodong Song, from the University of Illinois' Department of Geology said that the distinctly different two regions suggest how the inner core of the planet has been evolving.
"Over the history of the earth, the inner core might have had a very dramatic change in its deformation regime," said study researcher Xiaodong Song, from the University of Illinois' Department of Geology. "It might hold the key to how the planet has evolved."