Early schooling has taught us of the four fundamental states of matter: solid, liquid, gas, and plasma. Further education has introduced probably two or more states to that list, which may include pretty complicated names, like Bose-Einstein condensates. All in all, there’s a couple of things in that list that are far more complicated to explain compared to the first four ones, but there are definitely a lot more out there.
Thing is, identifying these states are more than just adding more things for kids to memorize or for adults to teach them; exploring the limits of matter allow scientists to peer into the inner workings of the universe, and give us glimpses into worlds far away from our own.
That last statement certainly appears to be the case with these new findings published in the journal Nature Physics, as a team of scientists just compressed water to extreme pressures, then blasted it to very high temperatures with focused lasers, creating a new state of matter known as superionic ice.
The findings, which were produced by a collaboration working with the US-based Argonne National Laboratory (ANL), comes as the latest in a string of news about the frontier of physics; it now joins the ranks of the “honeycomb” crystal made entirely out of electrons, as well as adding another point to the long list of water’s strange properties, which include freezing on graphene by “adding” heat instead of taking it away.
Said co-author, University of Chicago research professor, and beamline scientist at ANL’s Advanced Photon Source (APS) Vitali Prakapenka in an ANL news release: “It was a surprise—everyone thought this phase wouldn’t appear until you are at much higher pressures than where we first [found] it.”
These intrepid scientists successfully “mapped out” the properties of this new phase of matter a few years after it was first glimpsed for a short while in a study published in the journal Nature just a few years prior.
To get to this landmark achievement, the team squeezed a droplet of water between two diamonds, known as the hardest substance on Earth; the resulting pressure between the diamonds was about 3.5 million times the normal atmospheric pressure of Earth.
Afterwards, the team took advantage of the capabilities of the APS’s X-ray output, and shot it through the diamond to heat the water droplet inside it after heating it to multiple times the temperature of the Sun’s surface using a laser. In doing so, the X-rays “scattered” after colliding with the atoms inside the droplet, which gave clues to the arrangement of the atoms locked inside the pressed diamonds. The entire process lasted a mere 20 nanoseconds.
The pattern produced by the X-rays gave the ANL scientists the data that led them to this remarkable find, which Prakapenka described as “a new state of matter—so it basically acts as a new material, and it may be different from what we thought.”
Prakapenka describes the new “superionic” ice, which they consider a new state of matter, in a news release from ANL: “Imagine a cube, a lattice with oxygen atoms at the corners connected by hydrogen. When it transforms into this new superionic phase, the lattice expands, allowing the hydrogen atoms to migrate around while the oxygen atoms remain steady in their positions. It’s kind of like a solid oxygen lattice sitting in an ocean of floating hydrogen atoms.”
The scientists also expect the material to appear “dark,” since it interacts differently with light compared to other forms of ice. Given its penchant for existing only at extremely high pressures and temperatures, Prakapenka and team expect it to be the predominant form of ice on cold, massive planets like our Solar System’s own Uranus and Neptune.
Finally, the team also expects this unique form of ice to play a role in the magnetic field of whatever planet it calls home, which makes understanding this new state of matter crucial in understanding exoplanets. In the words of Prakapenka himself: ““This should stimulate a lot more studies.”
References
- Lerner, L. (2021, October 28). Scientists find strange black ‘superionic ice’ that could exist inside other planets. Argonne National Laboratory. https://www.anl.gov/article/scientists-find-strange-black-superionic-ice-that-could-exist-inside-other-planets
- Millot, M., Coppari, F., Rygg, J. R., Correa Barrios, A., Hamel, S., Swift, D. C., & Eggert, J. H. (2019). Nanosecond X-ray diffraction of shock-compressed superionic water ice. Nature, 569(7755), 251–255. https://doi.org/10.1038/s41586-019-1114-6
- Prakapenka, V. B., Holtgrewe, N., Lobanov, S. S., & Goncharov, A. F. (2021). Structure and properties of two superionic ice phases. Nature Physics, 17(11), 1233–1238. https://doi.org/10.1038/s41567-021-01351-8
- Sokol, J. (2019, May 8). Black, hot ice may be nature’s most common form of water. Quanta Magazine. https://www.quantamagazine.org/black-hot-superionic-ice-may-be-natures-most-common-form-of-water-20190508/
- Turner, B. (2021, November 15). Scientists discover “superionic ice,” a new form of water may lurk inside alien planets. LiveScience. https://www.livescience.com/stable-superionic-ice-made-first-time
