it has a solid core, like the Earth

Scientists from the National Center for Scientific Research (CNRS), from the Côte d’Azur University, the Côte d’Azur Observatory, Sorbonne University and the Paris-PSL Observatory have just confirmed that the Moon has a solid core (like the Earth). And it can explain many mysteries. The solid core in the center of the Moon can, for example, make it possible to better understand why it strangely lost its magnetic field. Four billion years ago, the Moon had a magnetic field 100 times stronger than Earth’s. It no longer exists and this disappearance could have a link with the formation of this nucleus.

Moreover, this solid core can also explain the presence of iron-rich elements on the surface of the Moon. This CNRS work published in the journal Nature indeed show that this core is composed of a metal whose density is close to that of iron. During lunar history, some of this denser material was able to rise to the surface, produce volcanic rocks and thus enrich the lunar crust with iron, before sinking below the surface.

A cherry pit in an apricot

This solid core measures 500 km in diameter, and corresponds to approximately 15% of the size of the Moon. It’s a bit like having a cherry pit in an apricot. Twenty years ago, analysis of the Moon’s rotation had already revealed the presence of a fluid outer core, not a solid seed. This time, it’s done, and what’s fascinating is that this discovery was made from Earth. It’s deduction and a lot of calculations. It was necessary to combine physics and the results of space missions.

To simplify, the scientists studied the deformations of the Moon induced by the effects of tides, they also studied its rotation, then taking into account these observations, they established hypotheses of materials which could compose this heart of the Moon, in comparing densities, temperatures, depths. The conclusion is that the Moon can only contain an inner solid core. This discovery will also make it possible to adjust various measuring devices, and therefore to better prepare for future lunar missions.