The discovery brings the total to more than 20 known ice phases – distinct structural forms of frozen water formed under varying pressures and temperatures. Most exist only in laboratories and do not occur naturally on Earth.
Yun-Hee Lee, lead author and researcher at the Korea Research Institute of Standards and Science, highlighted the discovery’s potential.
“The density of Ice XXI is comparable to the high-pressure ice layers inside the icy moons of Jupiter and Saturn,” he said.
» Full research paper: Multiple freezing-melting pathways of high-desnity ice through ice XXI phase at room temperature
The discovery may provide new clues for exploring the origins of life under extreme conditions in space.
The research team produced Ice XXI using a dynamic diamond anvil cell, a device that applies extreme pressure by squeezing materials between two diamonds. As pressure was increased and then reduced, researchers tracked crystallisation using X-ray lasers, capturing up to one million images per second.
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