在月球上找到最古老的地球岩石候选

2021年02月03日

Found on the Moon: Candidate for Oldest Known Earth Rock
Video Credit: NASA, Astromaterials 3D, Erika Blumenfeld et al.

Explanation: Was the oldest known rock on Earth found on the Moon? Quite possibly. The story opens with the Apollo 14 lunar mission. Lunar sample 14321, a large rock found in Cone crater by astronaut Alan Shepard, when analyzed back on Earth, was found to have a fragment that was a much better match to Earth rocks than other Moon rocks. Even more surprising, that rock section has recently been dated back 4 billion years, making it older, to within measurement uncertainty, than any rock ever found on Earth. A leading hypothesis now holds that an ancient comet or asteroid impact launched Earth rocks into the Solar System, some of which fell back to the Moon, became mixed with heated lunar soil and other rocks, cooled, and re-fragmented. The video features an internal X-ray scan of 14321 showing multiple sections with markedly different chemistries. Moon rocks will continue to be studied to learn a more complete history of the Moon, the Earth, and the early Solar System. Friday marks the 50th Anniversary of the Apollo 14 landing on the Moon.

Tomorrow’s picture: open space

在月球上找到最古老的地球岩石候选
影片提供: NASA, Astromaterials 3D, Erika Blumenfeld et al.

说明: 真的在月球上，找到最古老的地球岩石吗？很可能。故事得从阿波罗14号探月任务讲起。当年太空人艾伦·薛波在锥坑找到并带回的大型月岩样本14321，在地球分析之后，发现其中有块碎片神似地球的岩石，而非其他的月岩。更令人惊奇的，是这块碎片的定年高达40亿年，在纳入量测误差之后，还是比任何在地球上找到的岩石要古老。最可信的假说认为，远古时期有一颗彗星或小行星撞击地球，把地球岩石喷入太阳系，部分这些地岩掉到月球，和因撞击受热的月球土壤和月岩混杂在一起，后来降温后重新发生碎裂解离。这部呈现月岩14321内部X射线扫瞄的影片，显示这块月岩不同区域有非常不同的化学组成。月岩的研究工作将会持续下去，以了解月球、地球和早期太阳系的完整历史。这个星期五，将欢庆阿波罗14号登陆月球的50周年。

明日的图片: open space