Scientists reveal birth date of earth’s inner core.

A reassessment of ancient rocks has led scientists to estimate that Earth's inner core started to form earlier than was previously thought, around 1.3 billion years ago. As it started to freeze, the core began generating a bigger magnetic field, which continues to today. Earth's active core contrasts sharply with that of our neighbor Mars, whose strong early magnetic field died around four billion years ago. Our planet's magnetic field is generated deep in the planet by the turbulent motion o...
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