Earth’s last magnetic field reversal took far longer than once thought
Every several hundred thousand years or so, Earth’s magnetic field dramatically shifts and reverses its polarity. Geologist found that the most recent field reversal, some 770,000 years ago, took at least 22,000 years to complete. That’s several times longer than previously thought, and the results further call into question controversial findings that some reversals could occur within a human lifetime.
Paleontology News — ScienceDaily