Truth Revealed! Moon's interior is dry, says analysis of ‘rusty’ lunar rock

The truth about Moon's interior has been revealed in a new study by researchers at Scripps Institution of Oceanography at the University of California San Diego, published August 21, 2017 in the Proceedings of the National Academy of Sciences.

The Moon’s interior is likely very dry, revealed an analysis of a ‘rusty’ lunar rock, while contradicting a study that showed evidence of water on the Moon.

The results suggest that when the Moon formed it was “very, very, hot… Essentially an ocean of magma”, said James Day, a geochemist at the University of California, San Diego.

The study published in the journal Proceedings of the National Academy of Sciences is based on the analysis of fragments of the “Rusty Rock” — a rock collected from the Moon’s surface during the Apollo 16 mission in 1972 — which had rust on its outer surfaces.

The new chemical analyses Day and his team applied to the Rusty Rock revealed that the rock's composition is consistent with it coming from a very dry interior.

"It's a bit of a paradox," Day said. "It's a wet rock that comes from a very dry interior part of the moon."

Day found that the rust on the Rusty Rock is full of lighter isotopes of zinc, meaning it's probably the product of the zinc condensing on the moon's surface after evaporating during the sweltering period of the moon's formation.

"Zinc is a volatile element, so it behaves a bit like water under conditions of moon formation," Day said. "It's something like clouds forming from the ocean; the clouds are rich in light oxygen isotopes, and the ocean is rich in heavy oxygen isotopes."

"I think the Rusty Rock was seen for a long time as kind of this weird curiosity, but in reality, it's telling us something very important about the interior of the moon," Day said.

"These rocks are the gifts that keep on giving because every time you use a new technique, these old rocks that were collected by Buzz Aldrin, Neil Armstrong, Charlie Duke, John Young, and the Apollo astronaut pioneers, you get these wonderful insights."

"Their study says that all of the glass bead deposits on the lunar surface are 'wet,' which is a great observation. However, they cannot elucidate the mechanism of their formation," he said.

One of Day's PhD students, Carrie McIntosh, is currently doing her own work on the glass beads and the composition of the deposits."That's where we're going next," Day said. "It seems like the logical next step to try and solve this problem."