Next time Earth's magnetic field flips, compass needles will point South instead of North. But scientists can't say when it will occur, and until
now they've disagreed on how long the transitions take.
A new study pins down how long it took for the last four reversals to play out. It also finds that the dramatic turnarounds occur more quickly at
nearer the equator than at higher latitudes closer to the poles.
That means folks living during the next reversal -- which some scientists speculate might be underway -- will see compasses change and behave
differently in different locations, study leader Brad Clement, of Florida International University, told SPACE.com
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