New research using old data has helped uncover the structure of the Moon's core. The findings reveal what the early solar system was like.

Between 1969 and 1972, astronauts from five Apollo missions placed seismometers on the lunar surface. In 2011, a group of NASA researchers led by Renee Weber used the resulting seismic data to get a picture of what lies at the Moon’s center. Their results inferred a solid inner core and a liquid outer core. The data also implied a partly molten layer surrounding the lunar core.

Figure 1. Scientists get a new look inside the Moon

Scientists get a new look inside the Moon is shown in Figure 1. That snapshot of the Moon’s interior was somewhat blurry, thanks to seismic waves scattering through the lunar regolith, and the absence of instruments on the Moon’s far side.Now a team of French astronomers has provided a definitive picture. Their results agree in part with the NASA researchers’ predictions – but also include some surprises.

Gathering measurements

Arthur Briaud and his colleagues at the French space agency CNES, the Côte d’Azur Observatory and the Paris Observatory re-analyzed the data set used by Renee Weber and her colleagues for their 2011 paper. They also included data from other sources, including the GRAIL lunar satellites and the Lunar Laser Ranging experiment (LLR). They published their findings May 3 in the journal Nature.

GRAIL (Gravity Recovery and Interior Laboratory) was a NASA mission to produce a high-quality map of the Moon’s gravitational field. The twin spacecraft entered very low lunar orbits on New Year’s Eve 2011 and New Year’s Day 2012. They functioned until December 2012. The spacecraft transmitted and received data between one another and Earth, measuring the changes in distance between the two spacecraft. This allowed them to measure changes in the Moon’s gravity field in great detail and peer into its interior structure. [1]

Scientists have now revealed what's under the surface of the Moon, the long-guarded lunar secret. Over half a century after the Apollo mission, which opened the door for studying the lunar surface, astronomers have peaked under the hood and revealed part of its internal structure.[2]

There has been a lot of curiosity about what is Moon made of and there have been several debates about whether its inner core is solid or molten. Now researchers have found that the inner core of the Moon is in fact a solid ball with a density similar to that of iron, Science Alert reported. Well, the new findings open the door to a more accurate understanding of the Moon and our solar system.

A team led by astronomer Arthur Briaud of the French National Centre for Scientific Research in France said, "Our results, question the evolution of the Moon's magnetic field thanks to its demonstration of the existence of the inner core and support a global mantle overturn scenario that brings substantial insights on the timeline of the lunar bombardment in the first billion years of the Solar System."

The report further said that the seismic data effectively examine the inner composition of the objects in the solar system. It said that the way acoustic waves generated by quakes move through and reflect from the material inside a planet or moon can help scientists create a detailed map of the object's interior.

Mr Briaud and his colleagues collected data from space missions and lunar laser-ranging experiments to compile a profile of various lunar characteristics. They also conducted modelling with various core types to find which matched most closely with the observational data.

The researchers made several interesting findings. They found that the models that resembled the Moon describe active overturn deep inside the lunar mantle. In simpler terms, it means that denser material inside the Moon falls towards the centre, and less dense material rises upwards, a Science Alert report said.[3]

References:

1. https://www.astronomy.com/science/scientists-get-a-new-look-inside-the-moon/
2. https://www.indiatoday.in/science/story/scientists-peek-inside-the-moon-to-reveal-a-long-guarded-secret-2376250-2023-05-08
3. https://www.ndtv.com/science/scientists-reveal-whats-inside-the-moon-in-new-findings-4013844

Cite this article:

Gokula Nandhini K (2023), Scientists get a new look inside the Moon, AnaTechmaz, pp.468