Wandering of Earth’s magnetic poles maybe caused due to ocean currents

June 20th, 2009 - 1:47 pm ICT by ANI  

London, June 20 (ANI): A controversial new hypothesis has proposed that oceans’ currents are responsible for the slow wandering of the Earth’s magnetic poles.

According to a report in New Scientist, the theory has been put forward by physicist Gregory Ryskin of Northwestern University in the US.

Most scientists agree that the magnetic field is generated by movements of the molten iron that makes up Earth’s outer core.

However, Ryskin said that his idea that ocean movements may affect the field is worth investigating.

“Oceans could drag the field along global currents, and they could also generate their own weak magnetic field,” he said.

Classical fluid dynamics says that a conductive fluid - even a weak one like seawater - will drag magnetic field lines along with it as it moves, though the field lines may “slip” and fall behind.

Ryskin has calculated how the Earth’s magnetic field lines are dragged by ocean currents and modified by the oceans’ own magnetic field lines.

He found that the motion fits snugly with observations of how the magnetic field has been changing with time, in particular, how the geomagnetic poles have been moving.

In addition, weak electric currents generated as seawater flows through the Earth’s magnetic field generate secondary “oceanic” magnetic fields.

Ryskin included the effect of these magnetic fields in his calculations.

He also showed that the places on the globe where distortions on the geomagnetic field lines are greatest correspond to areas where ocean currents are strongest.

“The oceans almost certainly slightly modify the geomagnetic field observed at the surface due to electric currents flowing within the Earth and in the ionosphere,” said geophysicist Raymond Hide of Imperial College London.

“Geophysicists would be in Ryskin’s debt if he could improve on what others have already done. I wish him well,” he added. (ANI)

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