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Timeless mystery solved: Scientists uncover what is inside the moon's core

In a development that translates to a more accurate understanding of the Moon, scientists can now ascertain the components of the moon’s core. It is neither solid nor molten. In fact, the moon is indeed not made of green cheese. So, what is the moon made of?

What is the moon’s core made of?

There have been speculations about the Moon’s core. However, all of them can now be debunked, thanks to these new findings from a study conducted by a team of astronomers.

A team of scientists led by French astronomer Arthur Briaud has established that the likely contents of the Moon’s core is a solid metal ball covered by a molten outer layer. This conclusion followed an in-depth study that compared and analyzed simulations and existing data from various sources.

The study, done at the French National Centre for Scientific Research in France and published in the Nature Journal, relied on NASA’s Gravity Recovery and Interior Laboratory (GRAIL) 2011 mission data. NASA sent two spacecraft into orbit around Earth’s satellite as part of the mission.

The gravitational forces between both were measured as the spacecraft flew over various parts of their surface. With these, scientists could determine the position of one relative to the other.

Discovering what’s inside the moon’s core

Seismic data remains the most reliable means of assessing the composition of any object in the Solar System. Therefore, in addition to the GRAIL seismic data, Briaud and his team measured distances between the Earth and certain lunar areas using the Lunar Laser Ranging (LLR).

All of these were employed in creating an in-depth profile of the features of the Moon, after which different simulations of potential cores were built to identify the core that exhibits most of the known characteristics.

As noted by the team, their 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.”

They observed that the models that mirror our current understanding of the moon’s description showed active overturn deep in the mantle. Therefore, the denser material in the moon’s core is most likely situated at the center, while the less dense material moves upwards.

Moon’s core vs. Earth’s core

The study also revealed a level of similarity between the lunar core and the Earth’s. The inner core is solid in both cases, while the outer layer is fluid.

Their modeling also estimates the radius of the Moon’s inner core to be around 258 kilometers or 160 miles and the outer core 362 kilometers or 225 miles. The density of the inner core was also recorded to be similar to that of iron, which is about 7,822 kilograms per cubic meter. 

What does this mean for the future?

The findings of this study have confirmed earlier findings about a high possibility of an Earth-like lunar core. With more countries investing significant resources into exploring and possibly living on the lunar surface, knowing what is on the moon is a giant step in the right direction, both for the present and the future.

These fresh understandings have significant implications for the composition, structure, and history of the Moon’s formation. They will also go a long way to help space agencies leverage advanced technology and resources to fulfill these exploration goals and learn more about the Moon. 

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