Tuesday, May 14, 2013

Earth's center is out of sync

Scientists have so far assumed the rotation rate of the inner core to be constant because they lacked adequate mathematical methods for interpreting the data.

A new method applied to earthquake doublets – pairs of almost identical earthquakes that can occur a couple of weeks to 30 or 40 years apart – has provided the solution.

"It's stunning to see that even 10, 20 or 30 years apart, these earthquakes look so similar.

"But each pair differs very slightly, and that difference corresponds to the inner core.

"We have been able to use that small difference to reconstruct a history of how the inner core has rotated over the last 50 years," said Associate Professor Tkalcic.

This new method could help us understand the role of the inner core in creating the magnetic field that allowed life to evolve on Earth by acting as a shield from cosmic radiation.