The end of the world as we know it could come in any number of ways, depending on who you ask. Some people believe global cataclysm will occur when Earth’s magnetic poles reverse. When north goes south, they say, the continents will lurch in one direction or the other, triggering massive earthquakes, rapid climate change and species extinctions.
The geologic record shows that hundreds of pole reversals have occurred throughout Earth’s history; they happen when patches of iron atoms in Earth’s liquid outer core become reverse-aligned, like tiny magnets oriented in the opposite direction from those around them. When the reversed patches grow to the point that they dominate the rest of the core, Earth’s overall magnetic field flips. The last reversal happened 780,000 years ago during the Stone Age, and indeed there’s evidence to suggest the planet may be in the early stages of a pole reversal right now.
But should we really fear this event? What will actually happen when north-pointing compasses make a 180-degree turn toward Antarctica? Will the continents tear themselves apart, or are we in store for much more mundane changes?