Physics

Geology

Cell

Pure mathematics

Excursion

Mathematics

Magnetic field

Astronomy

Voltage

Political science

Geomagnetic reversal

Composite material

Earth's magnetic field

Chemistry

Field strength

L-shell

Materials science

Earth (classical element)

Polarity (international relations)

Polarity reversal

Quantum mechanics

Reversing

Field (mathematics)

Mercury's magnetic field

Biochemistry

Geophysics

Proceedings of the National Academy of Sciences

Significance Earth’s magnetic field is generated in Earth’s convecting liquid iron outer core and protects Earth’s surface from harmful solar radiation. The field has varied on different timescales throughout geological history, and these variations reflect changes deep within the Earth. Two of the field’s most extreme variations are reversals and excursions. During such events, the strength of the field decreases and the magnetic poles rapidly flip polarity, with reversals characterized by the pole retaining an opposite polarity, while excursions are marked by a return to the original polarity. Field strength over the past centuries has also been decreasing strongly; however, through analyzing previous excursions, we infer that Earth’s magnetic field is not in an early stage of a reversal or excursion.

Earth’s magnetic field is probably not reversing