<P> The time spans of chrons are randomly distributed with most being between 0.1 and 1 million years with an average of 450,000 years . Most reversals are estimated to take between 1,000 and 10,000 years . The latest one , the Brunhes -- Matuyama reversal , occurred 780,000 years ago , and may have happened very quickly , within a human lifetime . </P>
<P> The time spans of chrons are randomly distributed with most being between 0.1 and 1 million years with an average of 450,000 years . Most reversals are estimated to take between 1,000 and 10,000 years . The latest one , the Brunhes -- Matuyama reversal , occurred 780,000 years ago , and may have happened very quickly , within a human lifetime . </P>
how long ago was the last time earth 's magnetic field reversed
how long ago was the last time earth 's magnetic field reversed
780,000 years ago
780,000 years ago