by Carolyn Gramling, ScienceNews
This shift both prevented the protective magnetic field from collapsing and recharged it.
Earth’s inner core solidified sometime after 565 million years ago — just in time to not only save the planet’s protective magnetic field from imminent collapse, but also to kick-start it into its current, powerful phase, a new study suggests.
The finding, reported online January 28 in Nature Geoscience, supports an idea previously proposed by simulations that Earth’s inner core is relatively young. It also provides insight into how, and how quickly, Earth has been losing heat since its formation 4.54 billion years ago —key to understanding not only the generation of the planet’s magnetic shield but also convection within the mantle and plate tectonics.