Precious Metals Might Be Hiding Deep Beneath the Surface of the Moon

The moon may be hiding precious metals deep below its surface, an international team of researchers has said.

While the scientists didn't detect the metals directly, they did manage to link sulfur that has been detected in lunar volcanic rock samples to the presence of the chemical iron sulfide within the moon's interior, according to a study published in the journal Nature Geoscience.

"Examination of mineral deposits on Earth suggests that iron sulfide is a great place to store precious metals, like platinum and palladium," lead author of the study, James Brenan from Dalhousie University in Canada, said in a statement.

One of the leading hypotheses to explain the formation of the moon suggests that our natural satellite was born after a huge planet-sized object collided with the Earth around 4.5 billion years ago. As a result, scientists think that both the moon and the Earth have similar compositions.

However, researchers have long been puzzled by measurements of lunar volcanic rocks which show far lower quantities of precious metals than expected, if the hypotheses above are correct.

Attempting to shed light on this conundrum, Brenan and his team first recreated the extreme pressure and temperature of the moon's interior in the lab to see how much iron sulfide would form.

"Most of the work involved laboratory experiments in which we heated and pressurized samples of lunar basalt to conditions of the lunar interior—temperature up to 1,400 degrees Celsius [2,552 degrees Fahrenheit] and pressures up to 20,000 times atmospheric pressures to determine how much sulfur was required in the lunar magma composition for iron sulfide to be present," Brenan told Newsweek.

moon surface
The surface of the moon. NASA

Their findings indicated that most precious metals that did form in the moon's interior would be chained to iron sulfide deposits, meaning that they could not be carried by magma flows to the surface.

This could potentially explain the puzzle of why such low quantities of precious metals were found in lunar rock samples, the researchers say.

"Our results show that sulfur in lunar volcanic rocks is a fingerprint for the presence of iron sulfide in the rocky interior of the moon, which is where we think the precious metals were left behind when the lavas were created," Brenan said.

However, Brenan stresses that the findings can only be confirmed once astronauts or lunar spacecraft collect rock samples from deep inside the moon's interior—something that has never been done before.

"We have been scouring the Earth's surface for a fairly long period of time, so we have a pretty good idea of its composition, but with the moon that's not so at all," Brenan said.

"We have a grand total of 400 kilograms [881 pounds] of sample that was brought back by the Apollo and lunar missions... it's a pretty small amount of material. So, in order to find out anything about the interior of the moon we have to kind of reverse engineer the composition of the lavas that come onto the surface," he said.

This article was updated to include additional comments from James Brenan.