The interior of the Moon is probably quite dry , according to a new study by researchers at the Scripps Institution of Oceanography at the University of California, San Diego (USA) in which fragments of the ‘Rusty rock’ have been analyzed, a rock collected from the surface of Earth’s natural satellite during the Apollo 16 mission back in 1972.
The results of the study suggest that when the Moon formed, it was extremely hot, almost like an ocean of magma.
Experts believe that it would have been so hot that any volatile liquids, compounds, and elements under these conditions would have evaporated early in the Moon’s history.
Rusty Rock “is the only moonstone who returned with what appeared to be rust on their outer surfaces , ” said James Day, a geochemist at the Scripps Institution of Oceanography and lead author of work collecting the journal Proceedings of the National Academy of Sciences.
Where does that rust come from?
“It’s a big question if the moon is wet or dry, it may seem trivial, but this is really very important. If the moon is dry – as we have thought for the last 45 years, since the Apollo missions – it would be consistent with the formation. from the moon in some kind of cataclysmic impact event that formed it, “Day said.
And it is that the question of the humidity of the Moon is important because the amount of water and other elements and volatile compounds (that evaporate easily) provide clues about the history of the moon and how it was formed.
The implications of Rusty Rock have long puzzled scientists, as water is one of the essential ingredients in rust. But where could that water come from? The tests showed that both the rock and the rust were of lunar origin. However, new chemical analysis of this ancient rock reveals that the composition of the rock is consistent with the fact that it has a very dry interior.
“It’s a bit of a paradox. It’s a wet rock that comes from a very dry inner part of the moon, ” explains Day.
How is it possible? The key is that the rock is filled with isotopes lighter than zinc , which means that it is probably the product of zinc condensation on the moon’s surface after evaporating during these hot beginnings.
“Zinc is a volatile element, so it behaves a bit like water in lunar conditions. It is something like clouds that form from the ocean, clouds are rich in light oxygen isotopes and the ocean is rich in heavy oxygen isotopes. Likewise, the interior of the moon must be enriched in heavy isotopes and has been depleted of light isotopes and volatile elements, which means that it is dry, “says Day.
This new research contradicts a recent study published in July 2017 in Nature Geoscience by Brown University scientists who analyzed glass deposits found on the lunar surface and concluded that the presence of water in these deposits suggested that the interior of the moon is really wet.
James Day is skeptical about these results. We will have to wait to see the next steps to finally try to solve this problem.
Referencia: James M. D. Day el al., “Late-stage magmatic outgassing from a volatile-depleted Moon,” PNAS (2017). pnas.org/cgi/doi/10.1073/pnas.1708236114
