There is a lot of evidence that suggests that our Moon originated from a cosmic collision between a planet that was about the size of Mars and Earth in its early years. However, on a detailed level, a lot of information is still hiding in the clouds. Recent, unexpected findings might help uncover more about our Moon's origin story.

Image Credit: NASA's Scientific Visualization Studio / HDR tune by Universal-Sci

Recently a team of scientists searched for ice on the lunar north pole using the Mini-RF instrument on the Lunar Reconnaissance Orbiter. They scanned crater floors, hoping to measure an electrical property (dielectric constant) within lunar soil that has piled up in these locations. The dielectric constant is a value that compares the related abilities of a specific material and the vacuum of space to transmit electric fields. To their surprise, the researchers found that the constant got higher along with crater dimensions (up to a diameter of 3 miles). For craters wider than 3 miles, the property remained constant.

According to Essam Heggy, lead author of the paper published in the science journal: Earth and Planetary Science Letters, the relationship as mentioned earlier was a surprise to the team as it had no reason to believe it would exist. Since meteors that form more substantial craters also dig deeper into the Moon's subsurface, the scientists considered that the increasing dielectric constant of dust in larger craters could be the result of meteors unearthing iron and titanium oxides originating from under the surface.

If this theory is correct, it would suggest that only the first few hundred meters of the Moon's surface hold a scarcity of titanium and iron oxides. However, going deeper underneath the surface would increase the density of these materials significantly.

An artist impression of the Lunar Reconnaissance Orbiter. For their study the scientists used the on board Miniature Radio Frequency (Mini-RF) instrument - Image Credit: NASA / HDR tune by Universal-Sci

The team found precisely what it had suspected after comparing their radar images with metal oxide maps from the LRO Wide-Angle Camera, the Japanese Kaguya mission, and NASA's Lunar Prospector spacecraft. It turned out that larger craters were indeed more abundant in metals, proposing that more titanium and iron oxides had been unearthed from the depths beneath the Moon's surface.

Although the scientists emphasize that these results cannot immediately answer the outstanding questions about the formation of the Moon, it reduces uncertainty about the distribution of iron and titanium oxides in the lunar subsurface. Knowing more about this distribution could help in expressing a more explicit link between Earth and the Moon providing a more detailed foundation for their combined history.

The research team is currently examining craters on the opposite side of the Moon to uncover whether the same values hold true.

Sources and further reading: