Scientists Say Earth's Solid Iron Inner Core Spins East While Molten Outer Core Spins West

Posted on September 17, 2013

Scientists at the University of Leeds have determined that the Earth's solid iron inner core superrotates in an eastward direction. It spins fast than the rest of Earth. The inner core is about the size of the Moon. The outer core, comprised primarily of molten iron, spins westward at a slower pace. Scientists say the planet behaves in this way because it is responding to the Earth's geomagnetic field.

Seismometers measuring earthquakes traveling through the Earth's core have detected the superrotation of the innner core. The findings were published here in Proceedings of the National Academy of Sciences.

Dr. Philip Livermore, of the School of Earth and Environment at the University of Leeds, says in the announcement, "The link is simply explained in terms of equal and opposite action. The magnetic field pushes eastwards on the inner core, causing it to spin faster than the Earth, but it also pushes in the opposite direction in the liquid outer core, which creates a westward motion."

The scientists say the electromagnetic force responsible for pushing the inner and outer cores will itself change over time. There may have been times when the Earth's inner core underwent a westwards rotation.

EARTH