Superionic Ice: Understanding Neptune and Uranus bizarre magnetic fields

Beyond what we see on the surface, the extreme conditions inside planets cause some odd occurrences. The objects and such we perceive as familiar react very differently under high pressure and heat, resulting in unusual elements one could never imagine.

Within Earth’s solid inner core, scientists believe iron atoms move around silently. Meanwhile, Uranus and Neptune have hot black, heavy ice, which remains solid, superionic ice, that is both solid and liquid simultaneously, at least in lab experiments. The discovery of this ice deepens our comprehension, aiding in understanding the reason for Uranus and Neptune’s irregular magnetic fields.

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Unlike regular water with one oxygen atom and two hydrogen atoms, superionic ice is remarkably different. Studies suggest that it might be the most abundant form of water in the universe, filling planetary layers similar to those of Uranus and Neptune that have an atmospheric pressure of roughly two million times Earth’s pressure and interiors as hot as the sun.

Several universities in the United States and the Stanford Linear Accelerator Center lab in California discovered a new phase of superionic ice, facilitating further understanding. In 2019, scientists confirmed the existence of a structure where the oxygen atoms in superionic ice are locked in a solid cubic lattice. Meanwhile, ionized hydrogen atoms are let loose, flowing through that lattice-like electrons through metals, which gave superionic ice its conductive properties and incredibly high melting point.

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Physicist Arianna Gleason of Stanford University and her colleagues discovered a new phase of superionic ice, Ice XIX, in a recent study.

Their experiment observed a body-centered cubic structure with enhanced conductivity compared to its predecessor, Ice XVIII. Conductivity in different layers of this special ice affects the magnetic field generated, leading to strange results. Gleason and her colleagues concluded the conductivity of a layer of superionic ice similar to Ice XIX would promote the generation of wonky, multipolar magnetic fields like those found in Uranus and Neptune.

NASA’s Voyager II space probe flew by our solar system’s two ice giants and measured their highly unusual magnetic fields more than 30 years ago. The latest discovery of the new phase of superionic ice and its characteristics helps us understand why Neptune and Uranus have such off-kilter, bizarre magnetic fields.