Number 280 (Story #1), July 22, 1996 by Phillip F. Schewe and Ben Stein EARTH'S CORE SPINS INDEPENDENTLY of the rest of the planet. Columbia scientists Xiadong Song and Paul Richards have combined computer simulations with measurements of seismic waves traveling through the Earth to deduce the rotational behavior of the planet's deep interior. What they find is that the solid inner core---which might consist of a single immense crystal of iron 2400 km across---rotates slightly faster than the rest of the world. The tiny differential spin amounts to about one degree a year. This means that the equator of the inner core swivels past the inside of the outer core at a rate of tens of km per year, 100,000 times faster than the fastest tectonic plates move past each other up near the Earth's surface. A better understanding of how the core gimbals about would in turn provide insights into the nature of Earth's magnetic field, which has reversed itself many times over geological time. (Nature, 18 July 1996.)