Wednesday, October 16, 2013

Earth's Shifting Magnetic Field Linked To Planet's Changing Core

Earth's magnetic field shields the planet from charged particles streaming from the sun, keeping it from becoming a barren, Mars-like rock. For more than 300 years, scientists have recorded a westward-drifting feature in the field that models have been unable to explain.
By relying on insights gleaned from previous work, as well as data collected over nearly four centuries, an international team of scientists has been able to provide a model that accounts for the western drift of the magnetic field on one side of the planet.
"People have tried various configurations regarding the state of the core-mantle alignment," lead author Julien Aubert, of the Université Paris Diderot in France, told SPACE.com in an email."The ingredients were here, but they were never put in the right configuration, in particular for reproducing the geomagnetic westward drift."
Driven by temperature and gravity
The magnetic field that encases the planet is caused by interactions deep inside Earth's core. The inner core is solid, while the outer core features flowing liquid iron, which generates currents that in turn lead to magnetic fields.
The field surrounding the Earth changes over time, with shifts occurring most prominently in low latitudes in the Western Hemisphere. The fast-moving magnetic patches that occur near the equator drift approximately 10 miles (20 kilometers) per year. These changes are driven by intense regions of activity in the core, the cause of which scientists have been at a loss to explain. Read More