Metal 'Snow' May Power Earth's Magnetic Field

The power source for Earth's magnetic field may be magnesium that has been trapped in the core since our planet's violent birth, a new model suggests. Magnesium is the fourth most common element in the Earth's outer layers, but previously, scientists thought there was almost no magnesium in the core. Iron and magnesium don't easily mix, and researchers thought that the Earth's core was mostly iron.