Moon had a magnetic field for at least a billion years longer than thought | Science News

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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

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3:07pm, August 9, 2017
moon

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.

The moon had a magnetic field for at least 2 billion years, or maybe longer.

Analysis of a relatively young rock collected by Apollo astronauts reveals the moon had a weak magnetic field until 1 billion to 2.5 billion years ago, at least a billion years later than previous data showed. Extending this lifetime offers insights into how small bodies generate magnetic fields, researchers report August 9 in Science Advances. The result may also suggest how life could survive on tiny planets or moons.

“A magnetic field protects the atmosphere of a planet or moon, and the atmosphere protects the surface,” says study coauthor Sonia Tikoo, a planetary scientist at Rutgers University in New Brunswick, N.J. Together, the two protect the potential habitability of the planet or moon, possibly those far beyond our solar system.

The moon does not currently have a global magnetic field. Whether

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