I am amazed.

Now Bogue and his colleague Jonathan Glen of the United States Geological Survey in Menlo Park, California, say they have found a second example in Nevada. The lava rock suggests that in one year, Earth's magnetic field shifted by 53 degrees (Geophysical Research Letters, DOI: 10.1029/2010GL044286). At that rate, a full flip would take less than four years, but there could be another interpretation. "It may have been a burst of rapid acceleration that punctuated the steady movement of the field," says Bogue.

