From time to time, approximately every few hundred thousand years, the magnetic poles of our planet "flip": essentially, the north pole transforms into the south and vice versa. On average, this occurs roughly every 300,000 years, though the last time something likely went awry — it has been about 780,000 years since the last flip, according to IFLScience.
Paleomagnetic records indicate that over the past 160 million years, the Earth's magnetic poles have swapped places several hundred times. Unfortunately, we still do not know when the next shift will occur or why the planet has gone off schedule. Some experts, however, believe that another flip should have already happened.
Since 1831, when our northern magnetic pole was first accurately identified, it has moved northwest by more than 1,100 kilometers, and its speed of movement has increased from about 16 kilometers per year to 55 kilometers per year.
The Earth has a magnetic field created by processes occurring in the planet's core. Molten metal flows in the outer core, and as it cools, convective forces create movement similar to boiling water on a stove. The Earth's rotation also stirs the molten metal, generating electric currents.
Essentially, the planet's magnetic field resembles that of a bar magnet: it has a north and south pole, but it is much less stable. Since the forces behind it are constantly changing, this means that the field itself is also in constant motion. As a result, from time to time, the locations of the Earth's north and south magnetic poles gradually shift, and eventually, they completely swap places.
Unfortunately, the change in polarity is not periodic and therefore cannot be predicted. According to geophysicist Leonardo Sanotti, the flow of molten metal in the Earth's outer core is chaotic and turbulent, which is why polarity shifts occur during periods of low intensity of the geomagnetic field.
The Earth's magnetic field essentially protects us from the onslaught of solar wind particles and cosmic rays from deep space. During pole shifts, the field weakens, although it does not disappear completely.
According to the British Geological Survey, there is a possibility that during magnetic pole shifts, the planet may be exposed to increased harmful radiation. However, previous studies have found no correlation between past pole flips and mass extinctions on the planet.
On the Earth's surface, the atmosphere acts like an additional blanket, blocking all but the most energetic solar and galactic radiation. Even in the absence of a magnetic field, the Earth's atmosphere would still stop most of the radiation. For comparison, the Earth's atmosphere protects us from high-energy radiation as effectively as a concrete layer about 4 meters thick.
However, scientists acknowledge that a decrease in the intensity of the geomagnetic field could still affect us in other ways. For instance, our technologies may become vulnerable, with their protection from magnetic storms weakened. Additionally, researchers believe that the flip could also impact birds, fish, and sea turtles that use the magnetic field for navigation.