geodynamo tagged posts

There are several theories about how Earth and its moon were formed, most involving a giant impact. Now scientists at the University of Leeds and the University of Chicago have analyzed the dynamics of fluids and electrically conducting fluids and concluded that Earth must have been magnetized either before the impact or as a result of it.

They claim this could help to narrow down the theories of the Earth-moon formation and inform future research into what really happened. Their work is published in Proceedings of the National Academy of Sciences.

Professor David Hughes, an applied mathematician in the School of Mathematics at the University of Leeds, said, “Our new idea is to point out that our theoretical understanding of the Earth’s magnetic field today can a...

This is an illustration of ancient Earth’s magnetic field compared to the modern magnetic field courtesy of Peter Driscoll. Credit: Peter Driscoll

New work from Carnegie’s Peter Driscoll suggests Earth’s ancient magnetic field was significantly different than the present day field, originating from several poles rather than the familiar two. Earth generates a strong magnetic field extending from the core out into space that shields the atmosphere and deflects harmful high-energy particles from the Sun and the cosmos. The motion of liquid iron in Earth’s outer core drives geodynamo, which creates Earth’s magnetic field. This motion is driven by the loss of heat from the core and the solidification of the inner core.

But the planet’s inner core was not always solid...

This is an illustration of how the diamond anvil cell is used to mimic and study planetary core conditions. Credit: Stewart McWilliams

Earth’s magnetic field shields us from deadly cosmic radiation, and without it, life as we know it could not exist here. The motion of liquid iron in the planet’s outer core, a”geodynamo,” generates the field. But how it was first created and then sustained throughout Earth’s history has remained a mystery to scientists. New work sheds light on the history of this incredibly important geologic occurrence.

Earth accreted from rocky material that surrounded our Sun in its youth, and over time the most-dense stuff, iron, sank inward, creating the layers that we know exist today–core, mantle, and crust...

The gravitational effects associated with the presence of the Moon and Sun cause cyclical deformation of the Earth’s mantle and wobbles in its rotation axis. This mechanical forcing applied to the whole planet causes strong currents in the outer core, which is made up of a liquid iron alloy of very low viscosity. Such currents are enough to generate the Earth’s magnetic field. Credit: © Julien Monteux and Denis Andrault

The Earth’s magnetic field permanently protects us from the charged particles and radiation that originate in the Sun. This shield is produced by the geodynamo, the rapid motion of huge quantities of liquid iron alloy in the Earth’s outer core...