嫦娥五号样品“讲述”月球故事

Chang'e-5 sample“tells”the story of the Moon

嫦娥五号实现了中国首次地外天体采样,是中国深空探测的重要里程碑,并开启了中国月球科学研究的新篇章。嫦娥五号着陆在月球风暴洋北部,位于月球最年轻的月海玄武岩单元之一。遥感探测显示该地区具有独特的化学组成,如中等TiO_(2)含量和高Th含量。科学家利用先进的实验分析技术研究嫦娥五号月壤中的玄武岩颗粒,发现其形成于20亿年前的火山活动,比阿波罗号样品和月球陨石限定的月球火山活动结束时间晚8亿年。此年轻火山活动的诱发机制仍不清楚,但是有两个主流假说,即富克里普物质提供了额外热量导致月幔熔融或富水源区降低了熔点,可以被排除。新样品带来新发现,新发现催生新理论。月球长时间火山活动之谜仍未解开,新的理论亟待建立。

Chang'e-5 mission has achieved China's first sample return from extraterrestrial bodies.It is an important milestone of the Chinese Lunar Exploration Program,opening a new era of lunar scientific research in the country.Chang'e-5 landed in one of the youngest basalt units on the Moon,the northern Oceanus Procellarum.Orbital observation shows that the landing area has unique chemical composition,such as moderate TiO2 and high Th contents.Scientists applied state-of-the-art analytical techniques to study the basalt fragments in the Chang'e-5 soil sample and found that they were formed at about 2 billion years ago,800 million years later than the latest lunar volcanic activity dated by the Apollo samples and lunar meteorites.The trigger of this young volcanic activity is still unclear.However,two leading mechanisms can be ruled out,KREEP-rich sources providing an additional heat source for mantle melting or water-rich sources lowering melting point.New samples bring new discoveries,and the new discoveries give birth to new theories.The mystery of the long-term volcanic activity on the Moon is still unraveled,and new theories are about to be established.