Data from MESSENGER yield clues about planet’s early evolution
NASA, JHU Applied Physics Laboratory, Carnegie Institution of Washington
Mercury’s magnetic field has been up and running for roughly 3.8 billion years, researchers report online May 7 in Science. The finding provides new insight into how the innermost planet evolved during its more vibrant youth.
Magnetized rocks scattered across ancient volcanic plains preserve signs of the planet’s magnetic field from about 800 million years after the birth of the solar system, geophysicist Catherine Johnson and colleagues report. The fossilized magnetic field was detected by the MESSENGER spacecraft, which orbited the planet for four years before crashing April 30 (SN Online: 4/30/15).
The ancient magnetic field, generated by underground currents of molten metal powered by a rapidly cooling core, is a key piece to understanding the history of the