“An Earth's 'inner-inner core,' about half the diameter of the whole inner core,
has been found to have iron crystals ... aligned differently, that behave differently
from their counterparts in the outer-inner core. That means the Earth's inner-inner
core could be made of a different type of crystal.”
- Phys.org, February 9, 2015
The February 9, 2012, journal Nature Geoscience, reported a new research discovery of a small "inner-inner core" inside the Earth's whole inner core that is inside the Earth's outer core that is inside the Earth's mantle and all covered by the Earth's crust was published by T. Wang, X. Song and H. Xia, University of Illinois and Nanjing University, China. See NG link in Websites below.
The scientists tried using seismic sensors to gather wave signals that resonate after earthquakes. The concept is that an earthquake moves rock and dirt layers with huge energy like a hammer striking a bell. The first hit and loud sound are followed by a residual clear tone that lasts longer. It's that clear tone that Song et al used to literally look into the center of the Earth four thousand miles from the surface and made the surprising find of two different inner cores.
Phys.org summarized the discovery this way: "The Earth's inner core, once thought to be a solid ball of iron, has some complex structural properties. An 'inner-inner core,' about half the diameter of the whole inner core, has been found to have iron crystals in the outer layer of the inner core that are aligned directional north-south However, in the inner-inner core, the iron crystals point roughly east-west. ... Not only are the iron crystals in the inner-inner core aligned differently, they behave differently from their counterparts in the outer-inner core. That means the inner-inner core could be made of a different type of crystal." See link at end of this report.
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