News Flash: pole reversals won’t happen suddenly; won’t end world


Well done, UniverseToday contributor Tammy Plotner. Some excellent skeptical content has graced their pages recently regarding why a global magnetic pole reversal is nothing to fear. I suspect the need for this article owes largely to the rising pitch of fear with the impending disaster accompanying the Mayan calendar rollover

Because every other rollover in history has been met with an accompanying disaster, remember? We’re just ever so lucky to have survived both 1000 and 2000 CE! And my car totally exploded when it hit 90,000km recently! (It got better.)

Unlike a hard-wired magnet, Earth’s polarity isn’t constant – it moves around a bit. The reason we have a magnetic field is our solid iron core surrounding by hot, fluid metal. According to computer modeling, this flow creates electric currents which spawn the magnetic fields. While it’s not possible at this point in time to measure the outer core of our planet directly, we can guess at its movement by the changes in the magnetic field. One such change has occurred for almost 200 years now… Our northern pole has been shifting even more northward. Since it was first located, the pole has shifted its place by more than 600 miles (1,100 km)! What’s more, it’s speeding up. It would seem that it’s moving almost 40 miles per year now, instead of the 10 miles per year as recorded in the early 20th century.

Surely if the magnetic field were to disappear, it would be pretty bad for life on this planet — DNA would be shredded, animals would die of sunburn without the benefit of the radiation shielding the magnetic field provides, to the point where eventually, everything would die out. Everything. It wouldn’t happen catacylsmicly or instantly, mind you, but it would happen fairly quickly on a cosmic scale.

But there’s absolutely no way that magnetic field could just up and disappear. You’d have to put the brakes on every iota of angular momentum the core of the planet undergoes. The field itself will shift around a hell of a lot, though, because we’re sitting on top of a really squishy ball of goo with a hard crust, so all that’ll happen is the pole will wander — as it does now, at a rate of 40 miles a year (up from the 10 miles a year we’ve seen in early measurements). And really, all that’s going to happen if the poles reverse is that compasses will point the wrong way. Maybe maps will have to be turned upside down. Or, North and South will have to be reversed to maintain our historical compass measurements. Whatever happens, it wouldn’t be cataclysmic. And I’m sure it’s not going to happen any time soon, given how it seems to take place over several hundred thousand years every time it apparently has happened in the past.

TL;DR: don’t worry, be happy.

Comments

  1. says

    I am still pissed off about Nova’s episode that discussed this. Unfortunately I was watching it with Cay and they spent the first half of the episode talking about how it appears the magnetosphere was on the verge of dissipating – and the terrible things that would happen if it did. They then explained what was really going on in the second half and Caleb understood it. But the damage was done and even though he knew we weren’t actually about to lose the magnetosphere, he had nightmares about it for a couple of months after.

    For the record, I didn’t turn it off because by the time I realized what was going on (I was driving, so only heard it in bits and pieces) it was too late. I figured they would actually get to the truth soon (silly me) and that would be better than turning it off.

    That said, this is totally fascinating to me. I was especially keen on how they were working out that this has happened and how often. Blows my mind what we can learn from core samples…

  2. jakc says

    Hey – maybe things were fine in Canada after Y2K, but here in the States, we had about 3 months of power failures, plagues of zombies, cannibalism, and of course, the Bush presidential campaign.

  3. Nentuaby says

    Even at that, magnetic compasses are becoming pretty specialized equipment anymore. Gyro compasses and GPS receivers point serious navigators, cartographers, and any schlub with a smartphone to true north. It’s pretty much just wilderness orienteers that’ll be affected…

  4. says

    I remember seeing on some PBS show that the Earth was going to become a quadrapole and possibly even get up to 16 poles before settling back down to 2 poles with N at the South Pole. Something about how geologists thought that was how it happened before because of magnetic residue or whatever scientific gobbledy-goop.

  5. idonotknow says

    Re: #6 Ben Zvan

    I don’t know of any paleomagnetic studies with sufficient temporal resolution and global data coverage to truly say what the field looks like during a reversal, but the studies I’ve seen are all still consistent with a mainly dipole field during reversals, probably not as strongly dipolar as the current field, but not quad- or octo- or other-polar. It certainly is true that a dipole field isn’t necessary, Neptune and Uranus have predominantly non-dipolar fields.

  6. 'Tis Himself, OM says

    We’re just ever so lucky to have survived both 1000 and 2000 CE!

    What are you talking about? You computer geeks caused the Dark Ages when you ignored the Y1K problem. It took centuries to recover from that.

  7. tbrandt says

    Sorry to be nitpicky, but the sudden loss of the magnetic field would not wipe out life on Earth. The magnetic field does nothing to shield us from photons (like the UV radiation that causes sunburns). The atmosphere protects us from that, and the ozone layer in particular protects us from UV radiation. The atmosphere also protects us from energetic charged particles. We would get higher doses of these if the magnetic field disappeared, and cancer rates would probably go up, but life would not be wiped out.

    As an example, flight crews that regularly fly over the poles receive significantly higher doses of radiation (the charged particle kind, not the photon kind) than people at sea level. This is both because the Earth’s magnetic field tends to steer charged particles towards the poles (which produces aurorae) and because they are above much of the protective atmosphere.

  8. Dunc says

    You computer geeks caused the Dark Ages when you ignored the Y1K problem.

    The term “Dark Ages” is generally used to refer to the period between the collapse of the western Roman Empire and the re-emergence of written history in Northern Europe in the 8th or 9th century. 1000CE is generally held to be the beginning of the High Middle Ages.

    Yeah, I know, it’s just a personal bugbear…

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