The Moon's far side reveals a magnetic field stronger than we thought
The far side of the Moon provides clues to a previous magnetic field
ETH Zurich researchers used gravity and magnetic data from the Moon's far side to show that 4.2 billion years ago the lunar dynamo generated a field stronger than 10 microtesla—about a fifth to a third of Earth's current field. The buried volcanic complex in the Dewar region also explains mysterious lunar swirls and could guide future missions.
We can therefore be almost certain that the magnetic field must originate from a longer-lasting dynamo generated in the core.