polarity reversal

magnetism

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July 1, 2026

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The Earth's magnetic field, or geomagnetic field, is generated by the dynamo effect within its liquid outer core. This field extends into space, forming the magnetosphere, which protects Earth from the solar wind.1

A key characteristic of this magnetic field is polarity reversal, where the north and south magnetic poles swap places. These reversals occur irregularly, ranging from tens of thousands to millions of years apart. The exact mechanisms driving these reversals are still uncertain. During a reversal, the magnetic field weakens significantly, potentially allowing more solar and cosmic radiation to reach Earth's surface, which could impact life and lead to species extinction.12

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Earth
The geomagnetic field and magnetosphere
…of Earth’s magnetic field is polarity reversal. In this process the direction of the dipole component reverses—i.e., the north magnetic pole becomes the south magnetic pole and vice versa. From studying the direction of magnetization of many rocks, geologists know that such reversals occur, without a discernible pattern, at intervals…
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…of Earth’s magnetic field is polarity reversal. In this process the direction of the dipole component reverses—i.e., the north magnetic pole becomes the south magnetic pole and vice versa. From studying the direction of magnetization of many rocks, geologists know that such reversals occur, without a discernible pattern, at intervals…
Read More