Extreme-pressure experiment reveals a strange new ice phase

Researchers at KRISS observed water’s rapid freeze–melt cycles under ultrahigh pressure and discovered Ice XXI, the first new ice phase found in decades. Using advanced high-pressure tech and microsecond XFEL imaging, they uncovered complex crystallization pathways never seen before. Ice XXI’s structure resembles the high-pressure ice found inside Jupiter and Saturn’s moons, hinting at planetary science implications.