Re:Should happen every 23,000 years (Score 0)

There's a really cool Nova show on the topic of reversal. They've even been able to roughly model the chaotic nature of the reversal, which happens very quickly. They've even found lava that showed the magnetic field moving tens of degrees during the time it took to harden. But it also describes how there are localized reversals that fluctuate. Check out the cool graphics: http://www.pbs.org/wgbh/nova/magnetic/