Key Highlights:
- Scientists at Argonne National Laboratory have now created stable superionic ice that can be studied in greater depth.
- This type of ice is supposed to exist on ice giant planets such as Uranus and Neptune.
- According to the researchers, much more research is needed to understand what makes superionic ice tick.
Superionic Ice recreated
Water can take on much more forms than most people realize, and scientists have now replicated one of the most strange forms in the lab – a “hot black ice” that may exist deep within planets like Uranus and Neptune.
Superionic ice is a phase of water that occurs at extremely high temperatures and pressures, forcing water molecules to split into their constituent hydrogen and oxygen ions. The oxygen ions then form a cube-shaped lattice around which the hydrogen ions can freely travel. As a result, superionic ice has comparatively high conductivity, a low density, and a deeper tint.
Although the phase has been theorized for decades and experimental evidence began to emerge in the 1990s, it wasn’t until 2019 that scientists were able to create superionic ice in the lab. However, it barely lasted a fraction of a second in that experiment.
Scientists at Argonne National Laboratory have now created stable superionic ice that can be studied in greater depth. Pressure is applied first by compressing a sample of water in a diamond anvil cell, and then the water is heated with lasers. Finally, the Advanced Photon Source (APS), a strong X-ray laser, is used to photograph the arrangement of the atoms in the sample in order to determine what phase the water is in.
And, indeed, the experiments produced superionic ice, according to the findings. It first appeared at temperatures ranging from 627 °C to 1,627 °C (1,160 °F to 2,960 °F) and pressures of 20 GigaPascals. Surprisingly, that is significantly lower pressure than models projected for the formation of this phase.
“It was a surprise – everyone anticipated this phase wouldn’t arise until considerably greater pressures than where we originally saw it,” explains co-author Vitali Prakapenka. “However, owing to various strong techniques, we were able to very precisely map the characteristics of this new ice, which constitutes a new phase of matter.”
Present in ice giant planets
Producing superionic ice in the lab is more than a curiosity; researching it might help us understand how planets originate and possibly point us in the direction of where to hunt for alien life. This type of ice is supposed to exist on ice giant planets such as Uranus and Neptune, and if so, slushy mantles of superionic ice might create the magnetic fields of these worlds.
According to the researchers, much more research is needed to understand what makes superionic ice tick. Its conductivity, viscosity, and stability remain unknown, and things might vary radically when combined with salts or other minerals.
