magnetic field reversals

Cultural  

1. Changes in direction or orientation of the magnetic field of the Earth that have occurred from time to time. (Several hundred are known in the geological record.) Sometimes the north magnetic pole is near the geographic North Pole and sometimes near the South Pole in Antarctica.

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The causes of these reversals are not known in detail, but are thought to be related to the motion of fluids in the Earth's core.

Example Sentences

Two aspects of Schulten’s proposed compass mechanism are consistent with what is known about the birds’ compass: radical pairs are indifferent to exact external magnetic field reversals, and radical pairs are often formed when molecules absorb light.

From Scientific American

Anyway, magnetic field reversals have typically unfolded over the course of 1,000 years or so, providing plenty of time even for the U.S. federal government to adjust.

From Washington Post