Initial identification of γ iron – typically only stable at temperatures exceeding 900°C – on the moon
Samples retrieved by China’s Chang’e 6 lunar mission from impact craters have been found to contain γ-iron – an allotrope that usually remains stable only above 912°C. Scientists theorize that the magnetic fields detected in these particles might have originated from lunar impacts and could illuminate the regions of particularly high magnetic intensity on the moon.
Discussions about the possibility of the moon once possessing a liquid metal core that could produce strong magnetic fields, often referred to as a dynamo, and the duration of its existence have surged since the discovery of magnetized Apollo mission samples. This has given rise to the concept of a historical lunar dynamo, as noted by John Tarduno, a geophysicist from the University of Rochester in the US who was not part of the study. ‘However, there’s always been this persistent question … the lunar core is small, and it’s very challenging to create a long-lasting magnetic field in that small core.’