During its first few years of formation, the Moon likely went through a dramatic process in which a layer of dense material penetrated deep into its interior, mixed with the lunar mantle, and then returned to the lunar surface.
A team of University of Arizona researchers has discovered new evidence supporting one of the wildest formation theories of the moon, suggesting that Earth’s natural satellite may have changed dramatically millions of years after it formed.in a new study Posted on Monday in natural geosciencesResearchers observed subtle changes in the moon’s gravitational field, providing the first physical evidence of the sinking of mineral-rich layers.
In 2011, two NASA spacecraft began orbiting the moon to map the moon’s gravitational field. The GRAIL mission (Gravity Recovery and Interior Laboratory) discovered gravity anomalies on the moon, where one of the spacecraft accelerated as it flew over certain areas.
“These gravity anomalies indicate the presence of these dense rocks that extend about 24 miles (40 kilometers) deep into the moon’s interior,” Adrien Broquet, a researcher at the German Aerospace Center in Berlin and co-author of the study, told Gizmodo “. “So we tie these rocks to the entire evolution of the Moon, and we think these rocks are relics of the Moon’s early dynamic evolution.”
When it first formed, the moon was covered in a magma ocean. As the ocean cooled and solidified, the less dense layers on top began to crystallize, forming the moon’s mantle and crust. However, beneath the surface and closer to the moon’s core, denser layers take longer to crystallize. These layers are rich in iron and titanium, and because they are denser than the layers above them, they sink deeper into the moon’s interior. As they did this, the dense, mineral-rich layer mixed with the moon’s mantle, melted, and returned to the moon’s surface in titanium-rich lava flows (which we still see today).
The theory of this lunar flip has been around since the Apollo era, when astronauts collected samples from the moon and discovered high concentrations of titanium. However, recent research is the first to use the Moon’s subtle gravity anomalies to resolve formation models.
As NASA prepares to land astronauts on the moon for the upcoming Artemis mission, the new astronauts will collect more evidence to help us understand how our natural satellite was formed.
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