The moon is quite well researched – but there are still mysteries that drive research. One of them seems to be solved now.
Nice – The moon is Earth’s closest neighbor and the only alien celestial body that humans have visited. Nevertheless, it still poses many mysteries – for example, researchers are puzzled about how the interior of the moon is structured. Does the moon have a semi-molten core or does it also have a solid inner core? This question was unresolved for a long time. But now a research team has strong evidence that there is a solid inner core in the moon.
To study the interior of the moon, researchers use the same methods they use to explore the interior of the earth: seismic waves. The manned “Apollo” missions of the US space agency Nasa have left behind, among other things, a seismometer on the moon whose data show that the core of the earth’s satellite could be at least partially liquid. But the data are too imprecise to allow more precise conclusions about the interior of the moon.
New study: how the moon is built inside
A research team led by astronomer Arthur Briaud (Université Côte d’Azur) used data from space missions and geophysical measurements to find out more about the interior of the 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 comes closest to the observed data. “Our results (…) prove the existence of an inner core,” writes the research group.
In their study, the researchers show that the moon not only has a solid inner core – the structure of the moon is also apparently similar to that of the earth. The outer, semi-liquid core has a radius of about 362 kilometers. Inside is the solid inner core, which has a radius of about 258 kilometers. According to the calculations, the inner core has a density of 7,822 kilograms per cubic meter – which roughly corresponds to the density of iron. The outer, semi-liquid core has a lower density of 5025 kilograms per cubic metre.
The moon has a solid inner core – like the earth
The calculations by Briaud’s team confirm earlier research that processed the “Apollo” measurement data using current seismological methods and also concluded that there was a solid inner core. “The existence of a solid inner core is crucial for understanding the mechanism that leads to the appearance or not of a planetary magnetic field,” the research group writes in the study.
Space Newsletter
Subscribe to the free Space Newsletter and get the most important news in astronomy and space in your inbox once a week.
By examining lunar rocks, researchers know that the moon had a strong magnetic field about four billion years ago that disappeared about 3.2 billion years ago. Such a magnetic field is created by movement and convection in the core – with the knowledge of the nature of the lunar core, future research can explain how and why the magnetic field disappeared. (tab)