December 12, 2003

Magnetic Field Is Fading, but No Dire Effects Are Foreseen

from the NY Times: bq. At a meeting of the American Geophysical Union here on Thursday, scientists presented research investigating the cause of the decline, its possible effects on the planet and what might be learned from geological records of earlier reversals. bq. The decline, as measured by magnetometers on Earth's surface, is 10 percent in the last 150 years. "We're seeing it's actually decreasing at a fairly impressive rate," said Dr. John A. Tarduno, a professor of geophysics at the University of Rochester. bq. Still, long-term changes in the magnetic field are normal, and the scientists said the magnetic field could just as easily strengthen again. bq. Most scientists think that Earth's magnetic field is produced by electric current generated by chaotic eddies in the molten iron of Earth's outer core and that random changes in the eddies cause the reversals. bq. The magnetic field last flipped 780,000 years ago, but the time between reversals has varied from a few thousand years to 35 million years. Time to get out the felt-tip markers and relabel your compasses... :) Posted by DaveH at December 12, 2003 11:08 AM