"It is quite abnormal."

Superionic

Nobody quite knows what’s lurking at the very core of the Earth. Is it solid, liquid, or a new form of matter entirely?

With the help of his colleagues, Chinese Academy of Sciences physicist Yu He determined that our planet’s inner core is in a “superionic sate,” which technically neither a solid or a liquid but a weird intermediate state.

“It is quite abnormal,” He said in a blurb about the research. “The solidification of iron at the inner core boundary does not change the mobility of these light elements, and the convection of light elements is continuous in the inner core.”

The research could shed light on one of the longest running mysteries in earth science: the composition of the inner structure of our planet.

Under Pressure

Because it’s still impossible to drill down to the Earth’s core, the team chose to simulate its hellish pressures and temperatures using a computer.

As detailed in a study published in the journal Nature earlier this month, the team found that the swirling mix of hydrogen, oxygen, and carbon was in a superionic state, meaning that oxygen ions had formed a solid, while hydrogen ions floated around to form a kind of liquid. The iron atoms, however, were set in a crystalline structure.

“We find that hydrogen, oxygen and carbon in hexagonal close-packed iron transform to a superionic state under the inner core conditions, showing high diffusion coefficients like a liquid,” the team writes in its paper. “This suggests that the inner core can be in a superionic state rather than a normal solid state.”

The model may hold true, given previous research into the Earth’s inner core that found it may be softer than expected, swirling like a spinning snowball.

“Our results fit well with seismological observations,” He argued in the statement. “It is the liquid-like elements that make the inner core soften.”

READ MORE: Earth’s inner core: a mixture of solid Fe and liquid-like light elements [Chinese Academy of Sciences]

More on the inner core: The Earth’s Core Is Cooling Way Faster Than We Thought, Scientists Say


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