The inner core and the rest of the Earth are perpetually racing one another, and it seems the inner core is winning by a stunning distance. This proposition, once wholly abstract and theoretical, now has firm grounding in quantifiable observation.

That the solid inner core of Earth should rotate—and faster than its surroundings—has been suspected, modeled, and postulated for about a decade, but never verified. Now two seismologists from the Lamont-Doherty Earth Observatory, Xiaodong Song and Paul Richards, have announced that seismological records provide the evidence geophysicists need to confirm that the inner core is spinning.