Scientists from the Chinese Academy of Sciences have discovered that the innermost core of the Earth is not in a normal solid state but rather in a superionic state.
Image: anu.edu.au
According to a research report published in the journal Nature on February 9, the superionic state, an intermediate state between solid and liquid, is formed from solid iron and lighter elements that behave like a liquid in the innermost core of the Earth.
For a long time, scientists have believed that there are several lighter elements present in the innermost core of the Earth, in addition to iron, due to the core’s density being lower than that of pure iron. According to scientists, these lighter elements could include silicon, hydrogen, carbon, and oxygen; however, the state of these elements in the innermost core of the Earth has rarely been studied.
A research team from the Institute of Geochemistry at the Chinese Academy of Sciences and the Center for Advanced Research in Technology and High-Pressure Science in Beijing conducted research on various alloys of iron and lighter elements under high pressure and temperature conditions that simulate the environment of the Earth’s innermost core.
The researchers found that lighter elements such as hydrogen, oxygen, and carbon in alloys with iron transition to a superionic state under the conditions of the Earth’s innermost core, as evidenced by their high diffusion rates resembling those of liquids. This indicates that the innermost core of the Earth may be in a superionic state rather than a normal solid state.
The superionic state is a unique intermediate state of matter that exhibits properties of both solids and liquids. For example, in superionic water, oxygen ions form a crystalline lattice like in a solid, while hydrogen ions move around like in a liquid.
