Swinging Strength of Earth's Magnetic Field Could Signal Inner Core Formation - Eos

The magnetic record stored in rocks documents the liquid core’s behavior and possibly when the inner core formed. Whether it formed half a billion or more than a billion years ago, however, is up for debate.

Life as we know it requires an atmosphere. It is the air we breathe, our shield from harmful ultraviolet rays, and our defense against extreme temperature swings, like those on Mars. But Earths atmos… [+8312 chars]

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