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I keep reading about how every so often, Earth鈥檚 north and south magnetic poles 鈥渇lip鈥�. How long does it take for this to happen? Moments or years? And does the magnetosphere 鈥渢urn off鈥� when this change is taking place? Or is it more like turning a bar magnet through 180 degrees, with the poles moving across the planet鈥檚 surface and passing through the equator?

Geoffrey Clark, Douglas, Isle of Man

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