Scientists have made a remarkable discovery: they’ve observed a form of water called plastic Ice VII for the first time. This isn’t just a scientific oddity; it could exist in the deep oceans of distant planets.
So, what makes plastic Ice VII special? It forms under extreme conditions—high temperatures and immense pressure. When water is subjected to these conditions, its molecules rearrange themselves in unique ways.
To create Ice VII, researchers applied pressure up to 6 gigapascals and heated water to about 327 °C (620 °F). The team, using advanced tools at the Institut Laue-Langevin in France, carefully observed how the ice shifted from one phase to another.
Plastic Ice VII has a unique cubic structure where the arrangement of hydrogen atoms is quite complex. Scientists have long wondered what happens when this structure begins to ‘melt.’ Some theorize that while the structure loosens, the hydrogen atoms become more mobile and shift around.
Measuring this delicate behavior is tricky. One of the key techniques used in this research is quasi-elastic neutron scattering (QENS). This method allows scientists to track tiny movements within the material, giving insights into its dynamics.
Physicist Maria Rescigno highlighted the advantage of QENS, noting that it effectively reveals how molecules behave during these exotic phase changes.
When researchers conducted their experiments, they noticed hydrogens moving at a microscopic level as the plastic Ice VII heated up. However, they found something unexpected: rather than rotating freely, the hydrogen molecules were moving in a staggered manner. This may be due to the hydrogen bonds between the molecules being disrupted and reformed.
This discovery has implications for understanding icy worlds like Neptune and Europa, one of Jupiter’s moons. Researchers believe these planets might have had plastic Ice VII forms in their past, and studying them helps us learn more about their histories.
Looking ahead, scientists are interested in exploring how Ice VII transitions into its plastic form. This process could be smooth and gradual or happen suddenly, as suggested by models.
Physicist Livia Bove noted that this continuous transition is particularly fascinating. It suggests that plastic Ice VII could be a stepping stone to an even more exotic state of water known as superionic ice, where hydrogen atoms can move freely through the oxygen framework.
The findings have been published in Nature, opening new avenues for research in the field of water science.
