Demagnetized Earth?

NOVA recently did a show on the Earth’s magnetic field that is pretty sensationalistic, as science reporting goes. It turns out that the field is plummeting like a figurative rock, and that given present rates of decline it could drop away to zero within a dozen centuries or so. Zero magnetic field… is that a bad thing or a good thing? It’s a bad thing. Some scientists speculate that Mars was a reasonable place to hang out and swim in the ocean until it lost its magnetic field. Once magnetically denuded, the undeflected solar wind blew away all that life-giving water. A solar storm for us now just leads to pretty auroras in the arctic sky, but in the not too distant future (relatively speaking) it might be a scorching harbinger of planetary death.

It’s bad enough that we’ve gotten used to hearing about the sun vaporizing the Earth, say, ten billion years from now. Now we might fry up like a fritter in mere millennia. Fortunately, there’s another possibility: the magnetic field might just be swapping directions. A somewhat more sanguine NY Times article on the same topic bears a hopeful title: Magnetic Field Is Fading, but No Dire Effects Are Foreseen. Whew! I was starting to get worried.