Flippin’ magnets
I was watching a program on Channel 4 yesterday called “Magnetic Flip”* yesterday, when Mr. Bsag wandered in some time after it had started.
Him: “Oh, so what’s the looming disaster that will destroy the Earth this week?” Me: “We’re going to lose the Earth’s magnetic field, and then all our atmosphere and water will get blown away into space by the solar winds, and we’ll all be very dry toast.” Him: [Long pause] “Right. What do you want for dinner?”
If you’ve watched any science programmes at all on TV, you won’t be surprised to learn that the whole ‘atmosphere being blown away’ thing was a bit of a device to get our attention. OK, so there is evidence that it happened to Mars, but the decline in the strength of our own magnetic field seems to have another cause: the polarity is about to flip. This is something that usually happens at fairly regular 200,000 year intervals, but as it’s 700,000 years since the last flip, we’re a bit overdue for one.
The evidence for this was rather fascinating, and unusually varied, including sampling of the magnetic polarity in ancient pottery and mountains, searching the meticulous Navy records of magnetic anomalies going back a couple of centuries, and computer models (which were very pretty). The coolest experiment involved igniting a spinning ball of 10kg of sodium inside a very complicated piece of apparatus, in order to try to model what goes on in the Earth’s core. I have very exciting memories of what happens to a tiny pea-sized piece of sodium in water from chemistry lessons at school, so the thought of 10kg of sodium going up makes my eyes gleam.
In case you are still worrying about what will happen to us when all this flipping happens, here’s the bad and good news. The bad news is that magnetic compasses are going to be next to useless for quite a long time. While the magnetic fields is doing all its swirling around and rearranging itself, the weaker field and multiple fociâwhere the field enters or exits the earthâwill result in a greater level of cosmic radiation in inhabited areas. This will probably result in a higher incidence of cancers, but given that loads of other self-inflicted carcinogens will almost certainly increase, I’m not sure that we’ll really notice the difference. The good news? Well, the auroras will be spectacular, and you won’t have to freeze your ears off above the Arctic Circle to see them. Woo-hoo!
* I would post a link, but Channel 4 doesn’t have any information up about this program.
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You didn't mention the annoying effect they used each time they talked about the field flipping; a second or so of inverse colouring of whatever they were showing at the time (usually the same bit of CGI of the magnetic field pulsing around the earth, but occasionally some rugged looking prof on the beach in Hawaii). Incredibly irritating.
Still, nice film of London from the Eye. Did you notice all the songs were specially written for the program, too? That seems like a first.----- I saw that programme, too. It was all a bit of a downer, really! Oh well, so we're all going to die. That happens every week if you watch the science programmes on Discovery. Anyway, aren't we all going to die - "we" being people in western Europe and the eastern seaboard of North America - really soon, once some volcano on Lanzarote or somewhere explodes, causing a gigantic tidal wave.
OK, I have to admit that I was only half-watching the programme. And being male, I'm not so good at multi-tasking. But was it really any different to all those other "science" programmes?
by David (TEFL Smiler) @ 13/05/2003 5:05 pm • Permalink •
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paul: yes the inverting colours was a bit maddening. I also noticed the original music (I even hung on for the credits to see who it was. Some of the big-budget David Attenborough programmes have specially composed music, but it isn't common.
David: I saw the tidal wave one! And the giant meteor one. Let's face it--unless Bruce Willis is still around in his vest to save the world, we're stuffed. I have to admit that part of my motivation in watching this program was to find out how often the field flips. I give tutorials on animal navigation, and I talk a bit about the field flipping (most animal's magnetic compasses aren't based on polarity, so still indicate the 'correct' direction after the field has flipped). The thing is, I always say "...so the field flips every mumblemumble years...". I thought it was about time I actually found out what the interval is. Google might have been quicker, I suppose.
by bsag @ 13/05/2003 5:06 pm • Permalink •
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I love the "mumblemumble" bit!
by David (TEFL Smiler) @ 15/05/2003 5:05 pm • Permalink •
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