The Moon’s rocks remember ancient fire

Transcript

Long ago, the Moon likely had a weak internal dynamo, and Apollo samples show that some rocks recorded that ancient field before it vanished. Later, huge impacts may have vaporized surface material into plasma, briefly strengthening that weak field, while shock waves helped nearby rocks lock in the signal as they cooled. That is why the Moon has magnetized rocks today, especially on the far side and near the south pole, even though its global magnetic field is gone.