Research confirms Moon's inner core is solid with iron-like density, resolving debate and enhancing understanding of Moon and Solar System history.
Research findings suggest global mantle overturn and timeline of lunar bombardment in first billion years, questioning Moon's magnetic field evolution.
The interior composition of Solar System objects can be best analyzed using seismic data, which involves studying how acoustic waves produced by quakes move through and reflect off materials inside planets or moons, resulting in a comprehensive interior map.
Low-resolution Apollo seismic data can't determine inner core state, while models of solid and fluid core are supported; researchers combine various lunar characteristics to settle debate.
Various core models matched observational data; active overturn in the lunar mantle explains certain element presence in volcanic regions.
Their modeling suggests that the lunar core is similar to Earth's with an outer fluid layer and a solid inner core, with respective radii of 362 km and 258 km, making up about 15% of the Moon's radius.
The team found the Moon's inner core has a density close to that of iron, which is similar to the findings of a 2011 study that used seismological techniques on Apollo data.
Briaud and his team's results confirm earlier findings of an Earth-like lunar core, which has implications for the Moon's evolution and magnetic field, and suggests the possibility of seismic verification in the near future.