Earth’s Magnetic Field Now Twice as Intense as Past Average, Study Finds

The intensity of Earth’s magnetic field is currently twice as high as the average for the past 160 million years, researchers from the Scripps Institution of Oceanography in La Jolla report in today’s issue of the journal Nature. No one is quite sure of the meaning of that finding, however--whether, for example, it is a precursor to another change in the magnetic field, which protects life on Earth from energetic ions emitted by the sun.

Although the patterns of magnetic field reversal in the past are well known, fluctuations in the intensity of the field have been very hard to measure. But Lisa Tauxe and her colleagues have been able to collect historical data on the intensity from 21 new sites around the world and have concluded that the average intensity for the previous 160 million years was significantly lower than had previously been believed.

Compiled by Times medical writer Thomas H. Maugh II