The Icy Magnets of Uranus and Neptune ⚡ экспресс
The magnetic fields of Uranus and Neptune are anomalously tilted and multipolar. Recent studies confirm that their icy mantles are dominated by superionic water, which is thermodynamically stable under these conditions. This work demonstrates that superionic ice exhibits a pronounced proton thermoelectric effect: the maximum Seebeck coefficient inside Uranus reaches ~620 µV/K, and inside Neptune — 570–585 µV/K. Thus, temperature gradients in the icy shells drive proton convection, which generates the magnetic fields. This mechanism fully explains the differences in the planets' magnetic induction solely by the difference in their internal temperature gradients, and the calculated values agree with observations.
Uranus and Neptune have long puzzled scientists: their magnetic fields are heavily tilted and tangled, nothing like Earth's. The answer lay in an exotic form of water—superionic ice, which fills their interiors.
The temperature difference from the scorching core to the frigid surface drives protons to move from hot to cold, carrying entropy with them. Their organized flow creates an electric current, which in turn generates a magnetic field. So the ice acts like a natural thermocouple, converting a heat gradient into magnetism. The field's strength depends on how steep the gradient is: it differs on Uranus and Neptune, which is why their fields are not alike. Calculations based on proton flow match observations precisely.
Amazingly, the same effect powers a kitchen probe thermometer: there, a hot tip generates voltage in the wires. Only here, the charge carriers aren't electrons in metal but protons in ice—solid and fluid at once.
🎯 Pressure inside Uranus and Neptune is millions of times higher than on Earth, turning water into superionic ice—a substance that is both solid and liquid at once.