The Moon: Mysteries of the Near and Far Sides

The Moon has long captivated scientists for centuries. A recent study published in the journal Nature on October 8 has raised new questions about the peculiar difference between the near side and the far side of the Moon. This study not only offers an explanation for this disparity but also sheds light on the Moon’s violent history and its initial formation period.

The Moon’s History and the Giant Asteroid Impact

Around 4.3 billion years ago, the solar system was still in its early stages of formation. During this time, a massive asteroid collided with the far side of the Moon, creating the South Pole-Aitken Basin, a colossal crater stretching about 1,200 miles from north to south and 1,000 miles from east to west.

This enormous impact not only left a giant crater but also formed an elliptical shape, indicating that the asteroid struck the Moon at an oblique angle. Analyses have shown that the southern rim of the crater contains thick layers of debris, while the northern rim has less of these materials.

Chemical Element Distribution and Its Impact on the Moon’s Surface

The study revealed an unusual concentration of chemical elements such as potassium, rare earth elements, and phosphorus on the Moon’s near side. These elements are collectively known as “KREEP,” representing materials that did not integrate into the crust or mantle when the Moon was in its magma ocean stage.

This uneven distribution is interpreted as a result of the cooling magma ocean, where KREEP-rich materials became concentrated in the last remnants of liquid between the mantle and the crust.

Geological and Historical Impacts of Collisions

The crater resulting from the impact exposed a window through the Moon’s surface at the boundary between the regular crust and the magma-rich crust. This explains the uneven distribution of radioactive elements like thorium in the western region of the crater.

By studying the evolution of the magma ocean, scientists have been able to explain why the far side’s crust is thicker compared to the near side, which remains a puzzling mystery for lunar scientists today.

Conclusion

Many mysteries about the Moon’s early history remain, but recent studies like this one provide new insights that help solve these puzzles. Through future Artemis missions, scientists hope to collect samples from the Moon’s surface for analysis in advanced laboratories. These samples may hold the key to a better understanding of the Moon’s history and evolution.