Moon had a magnetic field for at least a billion years longer than thought
An analysis of an Apollo rock suggests two ways such a small body generated its field
![moon](https://i0.wp.com/www.sciencenews.org/wp-content/uploads/2017/08/080917_AY_moon-magnetic-field_main_free.jpg?fit=860%2C460&ssl=1)
HEATED PAST From around 4.25 billion years ago to at least as late as 2.5 billion years ago, the moon had a magnetic field, which dwindled in strength over time, a new study finds.
Goddard Space Flight Center/NASA