Earth's core formed in a hurry–during the first 30 million years after the birth of the solar system. That's the consensus of two independent research teams that used the same radioactive-dating technique to estimate the age of Earth and some of its neighbors. A previous analysis of similar data suggested the core took 60 million years to take shape, but the new estimates are in accord with several other lines of evidence, as well as the widely accepted theoretical models of planetary formation. Both teams report their findings in the Aug. 29 Nature.
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