Scientists confirm what’s inside the Moon

A comprehensive study published in May found that the Moon’s inner core is actually a solid ball with a density similar to iron. Researchers hope this finding will help resolve long-standing debates about whether the Moon’s inner heart is solid or molten, and lead to a more accurate understanding of the history of the Moon and thus the Solar system.

Investigation of the internal composition of objects in the solar system is most effectively carried out with seismic data. The way acoustic waves produced by earthquakes pass and reflect through material inside a planet or moon can help scientists create a detailed map of the object’s interior.

The internal structure of the Moon was detailed

We have lunar seismic data collected by the Apollo mission, but the resolution of this data is too low to accurately determine the state of the inner core. We know that there is a fluid outer core, but what this involves remains a matter of debate. Both solid inner core and fully fluid core models work equally well with the Apollo data.

To find out for sure, the team, led by astronomer Arthur Briaud of the French National Center for Scientific Research, created a profile of various lunar features by collecting data from space missions and Lunar Laser Measurement experiments. These include the degree of deformation resulting from its gravitational interaction with the Earth, its change in distance from the Earth, and its density. Modeling was then done with various types of kernels to find the closest match to observational data.

The research team found that the Moon’s core is very similar to that of the Earth, with a fluid outer layer and a solid core inside. According to their modeling, the radius of the outer core is about 362 kilometers and the radius of the inner core is about 258 kilometers. This corresponds to approximately 15 percent of the Moon’s entire radius. The density of the inner core the team found is approximately 7,822 kilograms per cubic meter. This is very close to the density of iron.

Briaud and his team say that their results confirm previous findings and provide strong evidence for an Earth-like lunar core. Given humanity’s plans to return to the Moon relatively soon, perhaps we won’t have to wait long for seismic confirmation of these findings.