What is inside the moon? A research group solves a decades-old mystery

The moon has been well researched – but there are still mysteries that drive research. Looks like one of them has been resolved now.

Nice – The Moon is Earth’s closest neighbor and is the only celestial body visited by humans. However, it still poses many mysteries – for example, researchers are puzzled as to how the moon’s interior is structured. Does the moon have a semi-molten core, or does it also have a solid inner core? This question has not been resolved for a long time. But the research team now has solid evidence of a solid inner core in the moon.

To study the interior of the moon, researchers use the same techniques they use to explore Earth’s interior: seismic waves. NASA’s manned “Apollo” missions left, among other things, a seismometer on the Moon whose data show that the core of the Earth’s satellite can be at least partially liquid. But the data is too imprecise to allow more accurate conclusions about the moon’s interior.

New study: how the moon is formed inside

A research team led by astronomer Arthur Priaud (University of Côte d’Azur) used data from space missions and geophysical measurements to learn more about the interior of Earth’s satellite. The study was in the journal nature published. The research group uses different computer models of the lunar core to find out which scenario is closest to the observed data. “Our results (…) prove the existence of an inner core,” the research team wrote.

In their study, the researchers showed that not only does the moon have a solid inner core — the structure of the moon also appears to be similar to that of Earth. The radius of the semi-liquid outer core is about 362 kilometers. Inside is the solid inner core, which has a radius of about 258 kilometers. According to calculations, the density of the inner core is 7822 kilograms per cubic meter – which roughly corresponds to the density of iron. The semi-liquid outer core has a lower density of 5025 kilograms per cubic meter.