Moon's 'lunar swirls' mystery solved: A volcanic, magnetic past

The mysterious lunar swirls, one of the solar system's most beautiful optical anomalies, may be a relic of the Moon's ancient volcanic activity and an internally generated magnetic field, scientists say. Working with what is known about the intricate geometry of lunar swirls, and the strengths of the magnetic fields associated with them, the researchers developed mathematical models for the geological "magnets." These lunar swirls may result from ancient, magnetic lava just below the moon's surface, according to one new study. However, in a previous studies, researchers found that the Moon's ancient magnetic field lasted one billion to 2.5 billion years longer than had previously been thought -- perhaps concurrent with the creation of lava tubes or dikes whose high iron content would have become strongly magnetic as they cooled.