3.2 Billion-Year-Old Surprise

Geophysicist John Tarduno, here in his electromagnetic field laboratory, is now pushing back further in time, investigating 3.5 billion-year-old rocks to learn more about when the Earth's inner core first formed.

The Earth's magnetic field was nearly as strong 3.2 billion years ago as it is today.

That finding by geophysics professor John Tarduno and research scientist Rory Cottrell contradicts previous studies. It suggests that even in its earliest stages the Earth was well protected from solar wind, which can strip away a planet's atmosphere and bathe its surface in lethal radiation.

"It's interesting because it could mean the Earth already had a solid iron inner core 3.2 billion years ago, which is at the very limit of what theoretical models of the Earth's formation could predict," says Tarduno.

The research was funded by the National Science Foundation.