magnetic polarity reversals

Magnetic polarity reversals refer to the phenomenon where Earth's magnetic field flips, with the magnetic north and south poles switching places. This process occurs over thousands to millions of years and is recorded in rocks, particularly at mid-ocean ridges where new crust forms. When lava cools, it locks in the direction of the geomagnetic field, producing a "magnetic fingerprint." These reversals help scientists understand the history of Earth's magnetic field, plate tectonics, and geological events. While they don’t happen regularly, the last reversal, called the Brunhes-Matuyama reversal, occurred about 780,000 years ago.