Now, in research published in Nature Communications, scientists from the Materials Dynamics Laboratory at the RIKEN SPring-8 Center, along with collaborators from the Tokyo Institute of Technology’s Earth-Life Science Institute and other institutes, have succeeded in measuring the speed of sound in mixtures of liquid iron and carbon in extreme conditions, allowing limits to be set on the core composition.

According to Alfred Baron, head of the Materials Dynamics Laboratory, “Understanding the composition of the liquid within the earth’s core is an important question, as it can give us clues about how the earth was formed.” It is known that the liquid in the core is mostly molten iron, but it has a density about 10% too small to be only iron, and geoscientists are trying to determine what elements are mixed with the iron to reduce its density.