In a celestial revelation, the lunar sample brought back by China’s Chang’e-5 mission is unraveling the Moon’s intricate history, offering a rich tapestry of new minerals and enigmatic silica combinations. This mission, breaking a lunar sample return hiatus since the Soviet Union’s Luna 24 in 1976, gifted scientists with 1.73 kilograms of regolith from the expansive Oceanus Procellarum.
Highlighted in the journal Matter and Radiation at Extremes, the study, led by researchers from the esteemed Chinese Academy of Sciences, immerses readers into the lunar treasure hunt. Among the lunar jewels discovered is Changesite-(Y), a novel mineral boasting colorless, transparent columnar crystals. Adding to the lunar intrigue, the sample boasts a perplexing mix of silica minerals, including a fragment housing stishovite and seifertite.
The researchers embark on a journey to decode the silica mystery. Typically found at much higher pressures, seifertite’s potential formation from α-cristobalite during compression, followed by a transformation into stishovite with a temperature increase, opens a lunar Pandora’s box of possibilities.
The study delves into the cosmic collision that shaped this lunar sample, estimating peak pressure (11–40 GPa) and impact duration (0.1–1.0 second). With the aid of shock wave models, they venture to estimate the resulting crater’s size, a cosmic fingerprint ranging from 3 to 32 kilometers wide, contingent on the impact angle.
Remote observations unveil that distant ejecta in Chang’e-5’s regolith likely trace their origin to the Aristarchus crater, the youngest among observed distant craters. Fragile under thermal metamorphism, the silica fragment’s likely origin from the Aristarchus crater collision paints a vivid picture of lunar dynamics.
This lunar sample return mission not only contributes to our understanding of lunar geological intricacies but also highlights the prowess of modern analysis in unraveling celestial mysteries. The Moon, it appears, still holds secrets waiting to be unveiled in its dusty regolith.
