Earth's magnetic field can shift 10 times faster than scientists thought

New simulations suggest Earth's magnetic field can change directions 10 times faster than previously thought.

Today, scientists use satellites to track Earth's magnetic field, but to understand the evolution of the planet's magnetic field, researchers must analyze sediment cores, lava samples and human artifacts.

Clues left in minerals that hardened long ago can only offer so much detail. As such, scientists continue to debate the true rates of magnetic field change across time.

"Understanding whether computer simulations of the magnetic field accurately reflect the physical behavior of the geomagnetic field as inferred from geological records can be very challenging," Catherine Constable, lead author of a new study exploring Earth's magnetic field shifts, said in a news release.

In the study, published Monday in the journal Nature Communications, researchers supplied magnetic field generation models with a record of time variations in Earth's shifting magnetic field over the last 100,000 years.

Previously, scientists estimated the planet's magnetic field shifted one degree per year at its fastest, but the latest analysis suggest the magnetic field can change up to 10 times more quickly.

The models showed such rapid changes are usually associated with pole reversals or geomagnetic excursions, when Earth's magnetic poles stray especially far from the planet's geographic poles.

Some 39,000 years ago, in Central America, the magnetic field altered direction at a rate of 2.5 degrees per year. Earth's magnetic field also featured fast rates of change when it experienced a brief reversal some 41,000 years ago.

The new analysis suggests faster, more dramatic changes in Earth's magnetic field are associated with reversed flux patches found on the surface of the planet's liquid core. Because the patches are more common at lower latitudes, local magnetic fields along the equator might experience more rapid periods of magnetic field changes.

Earth's magnetic field is generated by the movement of molten rock in Earth's core. The latest research could help scientists better understand the dynamic of Earth's liquid core.

"We have very incomplete knowledge of our magnetic field prior to 400 years ago," said lead study author Chris Davies.

"Since these rapid changes represent some of the more extreme behavior of the liquid core they could give important information about the behavior of Earth's deep interior," said Davies, an associate professor at the University of Leeds in Britain.

Previously, scientists have struggled to interpret the sometimes contradictory magnetic signatures found in ancient geologic samples. By combining field data with computer models, however, scientists were able to more accurately reconstruct ancient shifts in Earth's magnetic field.

"We have been able to show excellent agreement in both the rates of change and general location of the most extreme events across a range of computer simulations," said Constable, a researcher at the Scripps Institution of Oceanography at the University of California, San Diego.

"Further study of the evolving dynamics in these simulations offers a useful strategy for documenting how such rapid changes occur and whether they are also found during times of stable magnetic polarity like what we are experiencing today," Constable said.

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