Recent computational simulations indicate that icy giant planets like Uranus and Neptune may contain quasi-one-dimensional superionic carbon hydrides. This groundbreaking discovery could change how scientists perceive planetary interiors.
Diagram depicting hexagonal hydrocarbon compounds anticipated under conditions similar to those in Neptune. In this framework, carbon forms the outer helical chain (yellow), while hydrogen forms the inner helical chain (blue), aligning with the quasi-one-dimensional superionic behavior suggested by simulations. Image credit: Cong Liu.
Density measurements of Uranus and Neptune reveal that these colossal planets possess an unusual, hot, icy interlayer situated beneath an atmospheric envelope of hydrogen and helium, and above a rocky core.
While these layers are believed to comprise water, methane, and ammonia, extreme internal conditions likely result in exotic phases.
The physics associated with these high-pressure, high-temperature regions can lead to unconventional states of matter, prompting theorists and experimentalists to predict and recreate the phenomena they might encounter.
Dr. Cong Liu and colleagues at the Carnegie Institution for Science employed advanced computing and machine learning to conduct quantum physics simulations of hydrogenated carbon at pressures ranging from about 5 million to 30 million times atmospheric pressure (5-3,000 gigapascals) and temperatures of 4,000-6,000 K.
These simulations indicated the development of an ordered hexagonal framework where hydrogen atoms traverse helical paths, resulting in a quasi-one-dimensional superionic state.
Superionic materials are remarkable as they exist in a unique state between solids and liquids. Atoms of one type maintain their crystal arrangement, while atoms of another type gain mobility.
“This newly predicted carbon-hydrogen phase is particularly noteworthy because the movement of atoms isn’t entirely three-dimensional,” explained Dr. Ronald Cohen, also from the Carnegie Institution for Science.
“Rather, hydrogen preferentially migrates along distinct helical paths contained within the organized carbon structure.”
The direction of this atomic motion significantly influences heat and electrical transport within the planet’s interior.
This behavior has implications for understanding internal energy redistribution, electrical conductivity, and potentially the generation of magnetic fields in ice giants.
Additionally, this discovery broadens our comprehension of how simple compounds behave under extreme conditions and suggests that even basic systems can remarkably organize into complex phases.
“Carbon and hydrogen are prevalent in planetary materials, yet their combined behavior under giant planetary conditions remains poorly understood,” Dr. Liu remarked.
These findings are published in a study in Nature Communications dated March 16th.
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C. Liu et al. “Prediction of thermally driven quasi-one-dimensional superionic state of hydrogenated carbon under giant planetary conditions.” Nat Commun, published online on March 16, 2026. doi: 10.1038/s41467-026-70603-z
Source: www.sci.news
