Produced by: Mohsin Shaikh
Earth’s magnetic field is not fixed—it drifts, flips, and even weakens over time, altering navigation and planetary protection from solar radiation.
Since its discovery in 1831, magnetic north has shifted over 1,100 km, accelerating from 16 km/year to 55 km/year before suddenly slowing down in recent years.
Magnetic pole flips happen randomly, sometimes taking 10,000 to 50 million years. The last full reversal, the Brunhes–Matuyama event, occurred 780,000 years ago.
Around 41,000 years ago, the Laschamp event saw a brief but dramatic magnetic field reversal, lasting only 440 years with a field strength just 25% of today’s.
Credit: NASA
NASA reports that Earth’s magnetic field has weakened by 9% in 200 years, yet remains twice as strong as its million-year average, defying expectations.
During flips, Earth can develop multiple north and south poles, even reaching the equator. This unpredictable behavior disrupts geomagnetic stability on a planetary scale.
The magnetic field is driven by swirling molten iron in Earth’s outer core. This chaotic motion, influenced by planetary rotation and convection, fuels its unpredictable nature.
Some scientists speculate past magnetic flips contributed to species extinctions, but ice core data suggests limited climate impact, making the true effects still debated.
Dr. William Brown of BGS notes that magnetic north recently decelerated in speed—a phenomenon never seen before—leaving scientists unable to predict when the next reversal will occur.
Credit: NASA