Stanford researchers have made a significant breakthrough in the study of lunar magnetism, demonstrating that the magnetism of moon rocks remains unaffected by the spacecraft journey back to Earth or certain laboratory procedures. The findings, published in Geophysical Research Letters, have important implications for the understanding of the moon’s ancient magnetism and the feasibility of studying magnetic histories stored in extraterrestrial samples.
For decades, scientists have been puzzled by the mystery of the moon’s ancient magnetism. While analyses of lunar samples indicated the presence of an ancient magnetic field, questions were raised about the legitimacy of these findings. Some speculated that magnetism in the samples could have been acquired during the return mission through exposure to strong magnetic fields onboard the spacecraft.
Stanford University researchers, led by Assistant Professor Sonia Tikoo, conducted experiments to simulate long-term exposure of lunar samples to a magnetic field stronger than Earth’s. The results demonstrated that the magnetism in lunar samples was not adversely altered during the spacecraft journey or specific laboratory procedures.
The study involved two sets of lab experiments on eight samples from different Apollo missions. Researchers exposed the samples to a magnetic field about 100 times stronger than Earth’s for two days, simulating a return journey from the moon. Subsequent tests showed that the magnetic contamination could be easily removed using standard techniques.
Tikoo emphasized the importance of ensuring that spacecraft returning lunar samples do not adversely affect the rocks, stating, “You want to know that the spacecraft returning your sample is not magnetically frying your rock, essentially.” The successful removal of magnetic contamination bodes well for future space sample-return missions, as any contamination acquired during flight or on Earth can be addressed.
Paleomagnetism, the study of remanent magnetization in rocks, plays a crucial role in understanding the magnetic history of celestial bodies. The magnetic history of the moon is particularly important for comprehending its evolution and the potential impact on the delivery and retention of volatile substances.
As sample-return missions to various celestial bodies increase, the ability to conduct paleomagnetism studies without heavy magnetic shields opens up opportunities for a broader range of scientific research. The successful removal of magnetic contamination from lunar samples brings scientists one step closer to unraveling the mysteries of extraterrestrial magnetic fields and their role in planetary evolution.
