The giant impact that explains the mystery of the difference between the two faces of the moon

“The biggest differences between the visible side and the hidden side of the moon are related to the origin and chemical composition of these lunar zones,” explained Jose Maria Madito, an astrophysicist at the Andalusian Institute of Astrophysics (IAA-CSIC). To BBC Mundo, expert on asteroid impacts on the moon. Madito was not involved in the new study.

“On the visible face there are many large areas covered by a solid volcano called the oceans. However, on the dark side, these seas are very rare“.

With regard to the compound, Madido also pointed out that the space missions undertaken so far have been detected Large discrepancies in the abundance of certain elements.

“Therefore, for example, high concentrations of potassium, titanium, thorium, phosphorus and other elements known as rare earth group (REE) have been found on the visible face -“Rare-earth elements“).

“All of this suggests that throughout its evolution the Moon must have experienced some kind of phenomenon that led to these differences.”

About 2 groove.500 km

A new study published in the journal Science Advances suggests that the differences between the moon’s faces may have been caused by a massive impact. South Pole-Aitken Basin (SPA).

Medito explained that the South Pole-Aidken Basin is “a large impact crater located near the Moon’s South Pole.”

“About 2 in. In diameter.At 500 km and a depth of 12 km, it is one of the largest impact structures found on objects in the solar system.“.

The location of this bed falls in the area corresponding to the latent side of the moon, so it is not known from Earth, the expert added.

“From our planet, only the edge of the basin, formed by a mountain range 9 kilometers high, can be seen.”

The impact created by the South Pole-Aitken Basin may have been due to the spread of a large hot bloom in the lunar interior.

By spreading, That column carried a series of rare earths to the visible side of the moon. The excess of those heat-generating elements would have contributed to the volcanic activity, which created nearby volcanic flows.

“We know that big impacts like the formation of the SPA will generate more heat,” said Matt Jones, the study’s lead author and a graduate student at Brown University in Rhode Island.

“The question is how that heat affects the moon’s internal dynamics.

“This contributed to the melting of the mantle that forms the lava flows we see on the surface.“.

He explained a compound disorder called the procellular creep terrain (PKT) near the Moon – with concentrations of potassium, rare-earth elements and phosphorus, as well as heat-generating elements such as thorium. .

KREEP appears to be concentrated in the Oceanus Procellarum and surrounding areas, the largest of the nearby volcanic plains.

Developed by scientists Computer simulations of how heat generated by a giant impact changes the convection patterns inside the Moon And how it can redistribute KREEP material in the lunar mantle.

The lunar interior models suggest that it should be more or less evenly distributed below the surface. But this new model shows that the equilibrium distribution can be disrupted by the hot bloom of the SPA impact.

“According to the model, the KREEP material would act as a surfer on the heat wave emanating from the impact zone of the SPA.“The report from Brown University says.

As the heat sink stretched beneath the lunar surface, the object was pulled to the nearest side.

Researchers say that this work provides a reliable explanation for one of the great mysteries of the moon.

“The biggest open question in lunar science is how PKD came to be,” Jones said. “And the South Pole-Aitken impact is one of the biggest events in lunar history. This work brings those two things together, and I think our results are very exciting.”

In addition to Brown University, researchers from Purdue University, Stanford University, the Lunar and Planetary Science Laboratory in Arizona, and NASA’s Jet Propulsion Laboratory participated.

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