Taxonomy term

magnetic reversal

Ancient African villages shed light on Earth's magnetic field

Throughout Earth’s history, the planet’s magnetic field has changed polarity hundreds of times, with the magnetic north and south poles swapping positions. These reversals sometimes occur every few thousand years, or after hundreds of thousands of years. The last known magnetic reversal took place nearly 800,000 years ago, leaving many to wonder if we’re overdue for a reversal. Now, research from southern Africa, an understudied region, analyzing magnetized minerals preserved in the charred floors of 1,000-year-old torched huts has shed light on geomagnetic patterns that may indicate — or perhaps even trigger — such a switch. 
15 Dec 2015

Travels in Geology: Gubbio, Italy: A geologist's mecca

The author makes a pilgrimage to the medieval Apennine mountain town of Gubbio, Italy, where studies of the limestone layers just outside the town’s encircling walls produced one of the greatest geological discoveries of the 20th century.
02 Apr 2014

Musical magnetic reversals

Although Earth’s magnetic field currently points toward the North Pole, the planet’s magnetic dipole flips direction every few hundred thousand years or so. Engebretson tracked the last 85 million years of these magnetic reversals, with higher pitches representing shorter polarities (a period of time when the direction of the magnetic field stays the same), and lower pitches longer ones.

22 Sep 2009