The mysteries of our closest celestial neighbor, the Moon, continue to baffle and enthrall researchers. For the longest time, one of the pressing questions pertained to its core: is it solid or molten?
A recent investigation seeks to put this debate to rest by proposing that the Moon’s core is strikingly similar to Earth’s, composed of a fluid outer layer and a solid inner core.
The study of celestial bodies, especially their interior compositions, is a challenging endeavor. Seismic data remains the most reliable method to understand the internal structure of these celestial bodies. Waves generated by seismic activities, when interpreted accurately, paint a vivid picture of the interior components of a planet or moon.
The Apollo missions gave us a trove of invaluable seismic data about the Moon. However, the resolution of this data was not fine enough to conclude definitively the state of the Moon’s inner core.
The puzzle was whether the core was entirely liquid or had a solid center. The Apollo data seemed to corroborate both these models, making it difficult to reach a definitive conclusion.
The recent study led by Briaud took a comprehensive approach. By gathering data from multiple space missions and lunar laser ranging experiments, the team meticulously profiled the Moon’s characteristics, such as its gravitational interaction-driven deformations, variations in its Earth-bound distance, and density evaluations.
Sophisticated modeling, based on this data, was conducted to determine which core type aligns best with the observational data.
One key revelation from this study pertains to the presence of an “active overturn” deep within the Moon’s mantle. This phenomenon implies the constant sinking of denser material towards the center and the simultaneous rise of less dense material.
This research lends further credibility to this theory, especially since it’s been proposed to explain the presence of specific elements in the Moon’s volcanic regions.
The model that emerged as the closest match to the available data depicted the Moon’s core as being eerily similar to that of Earth’s.
With a fluid outer core spanning about 362 kilometers and a solid inner core with a radius of approximately 258 kilometers, these dimensions account for about 15% of the Moon’s total radius. Furthermore, the determined density of the inner core closely mirrors that of iron.
It’s interesting to note that these findings align well with a 2011 study led by NASA’s Renee Weber. Using advanced seismological techniques available at the time, Weber’s team reached a similar conclusion regarding the Moon’s core.
The importance of these findings goes beyond the mere anatomy of the Moon. The Moon’s magnetic field, once powerful but diminishing 3.2 billion years ago, is believed to be a product of activities within its core. Understanding the Moon’s core’s nature is vital to uncovering the history of its magnetic field.
As mankind sets its sights on revisiting the Moon soon, these revelations will undoubtedly influence lunar research. The prospects of conducting on-site seismic studies on the Moon are tantalizing.
Such endeavors could further validate these findings, paving the way for a more profound understanding of our enigmatic satellite and its evolutionary history in the vastness of our solar system.