Get ready for a mind-blowing revelation about our moon's ancient past!
The Chang'e-6 mission has unveiled a lunar secret that's as old as time itself.
Chinese scientists have analyzed basalt samples from the moon's far side, and their findings are nothing short of extraordinary. It turns out that a massive impact event, dating back a staggering 4.25 billion years, not only carved out the South Pole-Aitken (SPA) basin but also unleashed a powerful force that heated the deep materials on the lunar far side. This event, as reported by Science and Technology Daily, led to the loss of certain volatile elements, leaving a lasting imprint on the moon's history.
But here's where it gets controversial...
Researchers from the Institute of Geology and Geophysics (IGG) of the Chinese Academy of Sciences set out to solve a lunar mystery: how did large impacts during the moon's early days affect its deep interior? These impacts are believed to be the primary external force that shaped the lunar landscapes we see today.
Using high-precision isotope analysis, they detected subtle variations in isotope ratios, capturing the impact's traces with remarkable precision. Tian Hengci, the study's author and a research fellow at IGG, explained that this method allowed them to uncover the impact's secrets.
Science and Technology Daily highlighted the unique research value of isotope systems of moderately volatile elements like potassium, zinc, and gallium. In the intense heat generated by impacts, these elements undergo volatilization and isotopic fractionation, providing a sensitive reflection of the impact's temperatures, pressure, and material sources. Think of them as distinct "isotope fingerprints" that offer crucial insights into how impacts transformed the moon's crust and mantle.
In this study, the research team focused on high-precision potassium isotope analysis of the Chang'e-6 basalt samples. The results revealed a significantly higher proportion of the heavier potassium isotope, potassium-41, compared to Apollo samples from the lunar near side.
To pinpoint the cause of this difference, researchers systematically eliminated various factors, including cosmic ray irradiation, magmatic activity, and contributions from impactors. They ultimately confirmed that an early large-scale impact event altered the potassium isotope composition of the deep lunar mantle.
The extreme conditions at the moment of impact caused the lighter potassium-39 isotope to volatilize and escape, leaving behind a relative enrichment of the heavier potassium-41 in the residual material.
This loss of volatile elements likely suppressed volcanic activity on the moon's far side, offering key scientific clues to understand the influence of large impacts on lunar evolution. Tian explained that this discovery helps explain why the geological evolution of the lunar near side and far side differs so significantly.
In 2024, Chang'e-6 made history by returning 1,935.3 grams of lunar far-side samples to Earth. These samples, collected from the SPA Basin - the largest, deepest, and oldest basin on the moon - provided a unique opportunity to study the compositional differences between the near and far sides. Chinese scientists have made groundbreaking discoveries through their analysis of these samples, shedding light on the volcanic activity, ancient magnetic field, water content, and geochemical characteristics of the lunar mantle.
The Xinhua News Agency reports that these findings are pioneering breakthroughs, offering the first insights into the evolutionary history of the moon's dark side.
So, what do you think? Does this ancient impact event paint a clearer picture of the moon's past? Or does it raise more questions than it answers? Feel free to share your thoughts and theories in the comments below!
(Web editor: Wang Xiaoping, Liang Jun)
