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The Icy Magnets of Uranus and Neptune ⚡ экспресс

Original: "Protonic thermoelectric effect of Superionic H2O and magnetic field generation in Uranus and Neptune"
arXiv:2601.03659v2 · 2026-01-07 · CC BY · ⏱ 1 min · Exoplanets Materials
Temperature differences inside the ice giants turn ordinary ice into a magnetic generator.
Abstract

Uranus and Neptune are ice giants with really weird magnetic fields. Turns out, deep inside them, water is in a special 'superionic' state (kind of like ice and liquid at the same time), and temperature differences make charged particles move, creating magnetism. So, almost like a battery, heat turns into a magnetic field. So why then are the magnetic fields of these planets so different?

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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.

In this ice, oxygen atoms form a rigid lattice while hydrogen nuclei (protons) flow through it like a liquid.

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.

Scientists
Jacob BekensteinStephen HawkingCharles-Augustin de CoulombJames Clerk MaxwellLudwig BoltzmannJohannes Rydberg
Tags
Water hydrogen entropy
Laws
second law of thermodynamicsBekenstein-Hawking entropyCoulomb's lawBoltzmann distributionRydberg formulafirst law of thermodynamics
Original: arXiv:2601.03659v2 · CC BY · bridge42worlds