A pit on the surface of the Moon. Image Credit: NASA/GSFC/Arizona State University.

Yes, We Finally Know What’s Inside The Moon

"This finding aids in settling an enduring debate," experts have revealed.


For years, speculation about the Moon’s core composition has run rampant. While whimsical theories like “green cheese” have been easily dismissed, a more profound debate about the Moon’s inner structure has continued. However, new investigative results appear to be shedding light on this lunar mystery.

Contrary to whimsical tales, researchers have revealed that the Moon’s core is not made of cheese, green or otherwise. Shocking, huh? After an exhaustive study, results published in May actually revealed that the Moon’s core is strikingly similar to Earth’s – with a solid inner ball that possesses a density akin to iron.


“This finding aids in settling an enduring debate,” remarks Arthur Briaud from the French National Centre for Scientific Research. The nature of the Moon’s heart, whether molten or solid, holds the key to unlocking the Moon’s history and by relation, the Solar System’s chronicle.

Briaud and his team emphasize the significance of this discovery, “Our results question the evolution of the Moon’s magnetic field due to its clear demonstration of the inner core’s existence, lending substantial insights into the timeline of lunar events during the early Solar System.”

Peering into the Depths

The interior of celestial objects can be best understood through seismic data. Quakes produce acoustic waves that, upon interacting with internal materials, offer a glimpse into the object’s core.


Data from the Apollo mission was utilized, but its limited resolution posed challenges in determining the inner core’s state. Both solid and fluid core models seemed plausible with the Apollo insights.

Taking a meticulous approach, Briaud and his team aggregated data from various lunar missions and laser experiments. They then cross-referenced this data with various core models to ascertain the most accurate representation.

A Familiar Core

Their meticulous research revealed intriguing insights. They found active overturn deep within the Moon, suggesting that denser materials sink while lighter ones rise. This overturn theory, which explains specific volcanic region elements on the Moon, now finds more grounding.

Furthermore, they determined that the Moon’s core greatly resembles Earth’s, consisting of an outer fluid layer and a solid inner core. The densities they found are strikingly close to iron.

Interestingly, a 2011 study led by NASA’s Renee Weber arrived at a similar conclusion using advanced seismological techniques. Briaud’s team believes their results solidify those earlier findings, making a compelling case for an Earth-like lunar core.


Magnetic Musings and Future Expeditions

Understanding the Moon’s core holds implications for its magnetic history. We’ve known that the Moon once had a robust magnetic field, which began to wane around 3.2 billion years ago. The new findings may elucidate the reasons behind this decline. As humans gear up for another lunar visit, the chances of verifying these conclusions seismically might just be around the corner.

The full research has been detailed in Nature.

PLEASE READ: Have something to add? Visit Curiosmos on Facebook. Join the discussion in our mobile Telegram group. Also, follow us on Google News. Interesting in history, mysteries, and more? Visit Ancient Library’s Telegram group and become part of an exclusive group.

Written by Ivan Petricevic

I've been writing passionately about ancient civilizations, history, alien life, and various other subjects for more than eight years. You may have seen me appear on Discovery Channel's What On Earth series, History Channel's Ancient Aliens, and Gaia's Ancient Civilizations among others.

Write for us

We’re always looking for new guest authors and we welcome individual bloggers to contribute high-quality guest posts.

Get In Touch