Far out cosmology: how strange ice contributes (Introduction)

by David Turell , Sunday, October 15, 2023, 15:59 (403 days ago) @ David Turell

So cold it won't melt in Neptune and Uranus:

https://www.sciencealert.com/strange-form-of-ice-found-that-only-melts-at-extremely-hot...

"...hot, black, heavy ice – that's both solid and liquid at the same time – likely forms within the water-rich gas giants, Uranus and Neptune.

"Five years ago, scientists recreated this exotic ice, called superionic ice, for the first time in lab experiments; and four years ago they confirmed its existence and crystalline structure.

"Then just last year, researchers at several universities in the United States and the Stanford Linear Accelerator Center laboratory in California (SLAC) discovered a new phase of superionic ice.

"Their discovery deepens our understanding as to why Uranus and Neptune have such off-kilter magnetic fields with multiple poles.

"From our earthly surrounds, you'd be forgiven for thinking water is a simple, elbow-shaped molecule made up of one oxygen atom linked to two hydrogens that settle into a fixed position when water freezes.

"Superionic ice is strangely different, and yet it may be among the most abundant forms of water in the Universe – presumed to fill not only the interiors of Uranus, Neptune, but also similar exoplanets.

"These planets have extreme pressures of 2 million times the Earth's atmosphere, and interiors as hot as the surface of the Sun – which is where water gets weird.

"Scientists confirmed in 2019 what physicists had predicted back in 1988: a structure where the oxygen atoms in superionic ice are locked in a solid cubic lattice, while the ionized hydrogen atoms are let loose, flowing through that lattice like electrons through metals.

"This gives superionic ice its conductive properties. It also raises its melting point such that the frozen water remains solid at blistering temperatures.

***

"X-ray diffraction then revealed the hot, dense ice's crystal structure, despite the pressure and temperature conditions only being maintained for a fraction of a second.

"The resulting diffraction patterns confirmed the ice crystals were in fact a new phase distinct from superionic ice observed in 2019. The newly discovered superionic ice, Ice XIX, has a body-centered cubic structure and increased conductivity compared to its predecessor from 2019, Ice XVIII.

"Conductivity is important here because moving charged particles generate magnetic fields. This is the basis of dynamo theory, which describes how churning conductive fluids, such as Earth's mantle or inside another celestial body, give rise to magnetic fields.

***

"Gleason and colleagues conclude the enhanced conductivity of a layer of superionic ice akin to Ice XIX would promote the generation of wonky, multipolar magnetic fields like those emanating from Uranus and Neptune.

"If so, it would be a satisfying result more than 30 years after NASA's Voyager II space probe, launched in 1977, flew by our Solar System's two ice giants and measured their highly unusual magnetic fields."

Comment: this adds to the many properties water can have besides being vital for life to exist.