Scientists have identified a potential modern state of matter deep within Uranus and Neptune, where carbon hydride forms a spiral-like structure under extreme pressure and temperature.
The discovery emerged from quantum simulations conducted by Carnegie scientists Cong Liu and Ronald Cohen, who modeled conditions ranging from 500 to 3,000 gigapascals and temperatures between 4,000 and 6,000 Kelvin—equivalent to 5 million to 30 million times Earth’s atmospheric pressure and 6,740 to 10,340 degrees Fahrenheit.
In this state, carbon atoms form an ordered hexagonal framework while hydrogen atoms move through spiral, corkscrew-like pathways, creating a quasi-one-dimensional superionic state. This differs from typical superionic materials because atomic motion is confined to specific helical paths rather than occurring freely in three dimensions.
The research, published in Nature Communications, suggests this unique behavior could influence how heat and electricity travel through planetary interiors, potentially explaining the unusual magnetic fields of Uranus and Neptune, which are tilted and offset compared to other planets in the solar system.
Carbon and hydrogen are among the most abundant elements in planetary materials, yet their combined behavior under giant-planet conditions remains poorly understood, making this finding significant for understanding planetary formation and evolution.
The study builds on growing interest in planetary interiors driven by the discovery of over 6,000 exoplanets, as scientists seek to understand how planets form and evolve by combining observations, experiments, and simulations.
How this state could explain planetary magnetic fields
The directional movement of hydrogen in the spiral superionic state may affect electrical conductivity in ways that generate the observed magnetic field anomalies of Uranus and Neptune, which are significantly tilted relative to their rotational axes.
Why planetary interiors matter for exoplanet research
Understanding the internal processes of ice giants provides critical insights into the potential habitability of distant worlds, as internal dynamics influence whether exoplanets could maintain conditions suitable for life.
What is a superionic state?
A superionic state is a phase of matter where one type of atom remains fixed in a crystal lattice while another moves freely through it, exhibiting properties of both solids and liquids.
Why focus on carbon hydride specifically?
Carbon and hydrogen are abundant in planetary interiors, but their behavior under extreme conditions has not been fully characterized, making them a key focus for understanding planetary composition and dynamics.
