As for what the east-west axis means... According to the paper, they use a cylindrical anisotropy model and the best-fit axis is located at (9° N, 89° W) or its antipode at (9° S, 91° E). In other words, the crystals point along an axis near the equatorial plane through Central America and Southeast Asia.<p>The paper is pretty vague about why this would occur: "may represent a tectonic evolution of the inner core and thus our finding may indeed offer ‘clues about the inner-core history: its age, thermal process, and possibly an early convective event’."<p>Paper is available at <a href="http://www.nature.com/ngeo/journal/vaop/ncurrent/full/ngeo2354.html" rel="nofollow">http://www.nature.com/ngeo/journal/vaop/ncurrent/full/ngeo23...</a>
What does it mean for the crystals of the 'inner inner core' to be aligned in an 'east-west direction'? Its a sphere. Does that mean they are aligned in a ring, like the grooves in an lp (or the dots on a CD/DVD)? Why doesn't the graphic reflect that?
9N 89W is off the coast of Costa Rica, 9S 91E is off the coast of Singapore, which both locations seem to be kind of close to areas prone to earthquakes and tsunamis.<p>Also, it says it could have changed half a billion years ago. The current estimate of the formation of the moon is around 4.5 billion years ago, maybe these are related and they got their dating wrong?<p>The only thing I can find that happened half a billion years ago was the end of the the Neoproterozoic Era (the end of the Proterozoic Eon), which saw the first multi-celled life and the end of the Marinoan galciation, which could have subsided through global release of methane from equatorial permafrost.