Fresh look at Apollo moon rocks solves decades-old mystery about the moon's magnetic field

Scientists have resolved a decades-long debate about the moon's magnetic field strength by reanalyzing Apollo-era rock samples, discovering that the moon's field was mostly weak throughout its 4.5 billion-year history with only brief periods of strong activity. New research reveals that rocks with higher titanium content showed stronger magnetization, suggesting the moon's magnetic field temporarily strengthened for periods lasting decades to 5,000 years when titanium-rich materials melted deep inside the moon around 3.5 to 4 billion years ago.