Researchers have discovered a mass anomaly in the lunar crust. But it’s useless to imagine an immense extraterrestrial base buried beneath the surface. According to the researchers, this anomaly would simply be the result of an asteroid impact.
“An unexpected and considerable mass.” This is what scientists from the Baylor University (USA) found on the Moon as they sought to measure subtle changes in the intensity of gravity around our natural satellite. Researchers have an explanation for what this may be: it could indeed be a mass of metal from the impact of the asteroid that crashed there to form the crater. According to Peter James, professor of planetary geophysics, “a pile of metal five times bigger than the big island of Hawaii.”
Remember that the South Pole-Aitken Basin is not only the largest basin of impact of the Moon’s surface, but also the largest of our solar system. It is no less than 2,500 kilometers in diameter and 13 kilometers deep.
The result of an impact
The huge excess mass found by researchers at Baylor University could result from a high concentration of particularly dense oxides. This could have occurred in the last phase of the solidification of the lunar magma. A magma itself resulting from the impact of the planetoid Théia with our Earth and which would have given birth to the Moon.
Some computer simulations rather confirm another hypothesis. The researchers show that under certain conditions, at the moment of impact, the iron and nickel core of a large asteroid can be scattered in the upper mantle – the layer between the crust and the core – from the moon. “Our calculations suggest that a sufficiently dispersed nucleus could have stayed in the cloak until today instead of sinking into the moon’s core,” Peter James explains.
An extraordinary natural laboratory
Be that as it may, Peter James believes that the Pôle Sud-Aitken basin is “one of the best natural laboratories for the study of catastrophic events.” This one, indeed, was formed about 4 billion years ago and was incredibly well preserved. His study is also important for NASA’s upcoming lunar missions in this area.
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