The Icy Magnets of Uranus and Neptune ⚡ экспресс
Deep inside Uranus and Neptune, water exists as superionic ice — hot, solid, yet with protons that can move around. Researchers have shown that this ice has a strong proton thermoelectric effect: a temperature difference generates a flow of charged particles, which in turn creates a magnetic field. The maximum Seebeck coefficient for Uranus reaches ~620 µV/K, while for Neptune it's lower — 570–585 µV/K. This explains the differences in the planets' magnetic fields solely through their internal temperature gradients, without needing other factors. Interestingly, these giant 'magnetic dynamos' run on protons here, not on electrons like in the metals we're used to.
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.