[freebeard]

Eh, not nearly as interesting as what the core of the earth is made of.

Is this what you were speaking of?

www.livescience.com: Earth has a hidden layer, and no one knows exactly what it is

Strangely, when [siesmic] waves pass through the core from north to south, they travel faster than waves passing through the core parallel to the Earth's equator. No one knows why this is, Stephenson said, but it's a consistent finding. The technical term for this oddity is anisotropy.
[snip]
Stephenson and her colleagues brought together a dataset of about 100,000 earthquake waves that passed through this level of the core and applied an algorithm that searches for the best physical explanation of what's going on to explain the data. What they found was that in the inner-inner core, starting about 400 miles (650 km) from the center of Earth, the anisotropy in the slow direction isn't quite parallel with the equator anymore, but 54 degrees off.