Nature:
By recording distant earthquakes, seismologists George
Helffrich of Bristol University and Satoshi Kaneshima of Kyushu
University have deduced the presence of a solid layer of
sulfur, oxygen, and other light elements that sits between
Earth's solid inner core of iron and its liquid outer core of
iron. If the light elements were once distributed throughout
the inner core, their upward passage as the core solidified
could have provided the impetus needed to start Earth's
magnetic dynamo. That idea, as
Nature's Geoff Brumfiel reports, awaits
confirmation.
