Exotic Ice | weatherology°
By: Meteorologist Michael Karow
Updated: May 19th 2020

Exotic Ice

It freezes at 32°F (0°C) and boils at 212°F (100°C), what more about water is there left to discover? It turns out, we’ve only just begun to understand the behavior of this seemingly ordinary substance, H2O. Under extreme pressures and temperatures, like those found in the mantle layer of giant planets such as Uranus and Neptune, water can form an entirely new state of matter called superionic ice. The first x-ray measurements of superionic ice were taken in 2019 by a team of scientists at Lawrence Livermore National Laboratory.

The conditions under which water changes into the superionic ice phase do not normally occur on Earth. In order to study this exotic state of matter, the research team had to fire one of the most powerful lasers in the world at a droplet of water. The laser created shock waves that raised the pressure of the water to millions of times that of our own atmosphere, and raised its temperature to over 3,000°F (~1,700°C). At these extremes, the water formed a new state of matter that is described as black, hot ice. This superionic ice conducts electricity almost as well as metal, as the oxygen atoms form a rigid lattice, with
hydrogen atoms free flowing in the interior, like a liquid.

This latest find confirms in the laboratory what computer simulations had first hinted might happen under such extremes, back in 1988. Around this same time, the spacecraft Voyager 2 was passing by the ice giants Uranus and Neptune, where it measured strange magnetic fields for both planets that didn't exhibit the typical north and south magnetic poles aligned with their rotation axes, as the other planets have. This was the first clue that their interiors didn't consist of the same type of swirling, molten, conductive material as the other planets, but instead was being generated by a thin outer mantle of superionic ice around the core.

laser shock compression superionic ice LLNL
Image of the laser-driven shock compression experiment to create and study the properties of superionic ice - [M. Millot/E. Kowaluk/J.Wickboldt/LLNL/LLE/NIF]
Artistic rendering laser compression LLNL
Artistic rendering of the laser compression experiment, showing the shock wave passing from left to right - [Marius Millot/Federica Coppari/Sebastien Hamel/Liam Krauss]
Artist conception layers Uranus Neptune Lasskogen
Artist conception of the inner layers of ice giant planets like Uranus and Neptune - [Morten Lasskogen]