New Theory of Earth's Magnetism Might be 'Nonsense'

An artist's rendition of the Earth's interior structure. As depth increases in the planet, so does the temperature and pressure. In this diagram the crust and upper mantle is grey, the lower mantle is yellow, the outer is core orange, and the inner core is bright orange. Credit: Russell Hemley

There's a wild new debate brewing about how Earth's magnetic field works, and it goes to the very core of our planet.

Scientists have long thought the magnetic field, which protects life on Earth from harmful solar and cosmic radiation, is generated by rotation of an iron core that acts like a dynamo. But much about the process remains mysterious.

A controversial new study posits that the flow of seawater causes minor fluctuations in the magnetic field. Gregory Ryskin at Northwestern University published his idea in New Journal of Physics.

"I strongly believe the new hypothesis is just nonsense," geophysicist Robert Parker of the University of California, San Diego said in a National Geographic News article.

"This article is controversial and will no doubt cause vigorous debate, and possibly strong opposition, from some parts of the geomagnetism community," said Tim Smith, senior publisher of the journal. "As the author acknowledges, the results by no means constitute a proof but they do suggest the need for further research into the possibility of a direct connection between ocean flow and the secular variation of the geomagnetic field."