External forces beating up the ancient moon may explain how it once maintained a magnetic field for more than 400 million years — longer than scientists had thought such a small object could be magnetized.
Either wobbly rotation produced by Earth’s gravitational tug or asteroids smacking into the lunar surface may have triggered enough turbulence in the moon’s molten core to generate a long-lasting magnetic field, report two teams of scientists in the Nov.
Log in
Subscribers, enter your e-mail address for full access to the Science News archives and digital editions.