Recent scientific research has uncovered fascinating details about the Moon’s inner workings, stating that a goo-like substance is moving beneath its surface.
In a study published in AGU Advances, researchers discovered that a layer of semi-molten material sits between the Moon’s metal core and its mantle, behaving similarly to ocean tides on Earth. The gravitational forces of the Sun and Earth are causing this gooey layer to move.
“Just like the Moon raises tides on the Earth, the Earth (and Sun) raise tides on the Moon,” the researchers explained. They marked it as the “first measurement of the Moon’s yearly gravity changes due to tides.”
This discovery offers direct evidence that backs long-held theories about the Moon’s internal structure, yet it also introduces intriguing new questions. How did this molten layer develop? Its composition? And how does it stay warm enough to maintain its soft, fluid state?
The research team used data from NASA’s Gravity Recovery and Interior Laboratory (GRAIL) and the Lunar Reconnaissance Orbiter to make these observations. These missions gathered gravitational data and mapped lunar features, allowing scientists to track the Moon’s monthly and annual tidal shifts for the first time.
The study suggests that this partial melt layer lies beneath the Moon’s rocky mantle, which is composed of magnesium-iron silicate minerals and pyroxene. “Only models with a softer layer at the bottom of the mantle match all our measurements,” researchers noted. However, maintaining such a soft layer presents a new scientific puzzle: what keeps this region warm and flexible?
The discovery of this goo-like layer has implications for our understanding of the Moon’s thermal state and its evolutionary history. The fact that this layer remains warm and malleable despite being buried deep within the Moon adds complexity to existing lunar models.
“Such a soft layer, often thought to be partial melt, needs to be maintained,” researchers said.
This revelation could also pave the way for future discoveries in lunar geology. As the scientists move forward and continue to investigate the Moon’s internal structure, they may uncover even more about its origins, its relationship to Earth, and its broader role in the solar system.