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Science

Bad News for Earth's Magnetic Field 102

Posted by timothy from the or-at-least-fans-of-it dept.
jabex writes "Scientific American's website has an article about the overdue magnetic field flip. According to research published in the journal Nature, it could take anywhere from 2000-10000 years to complete. That's a long time without a protective magnetic field."
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Bad News for Earth's Magnetic Field More

Bad News for Earth's Magnetic Field

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  • The Earth's magnetic field is overrated (Score:5, Funny)

    by Rapid Home Offer ( 770408 ) * on Monday April 12, 2004 @07:53PM (#8842951) Homepage Journal
    Who needs the Earth's magnetic field, anyways? As long as I have my ozone layer, and my handy dandy lead codpiece, everything is going to be okay.

    (Doesn't everybody have a lead codpiece?)
  • Just as long as Robert Sawyer isn't correct (and it's very unlikely that he would be, since it was just a novel, damnit) and human consciousness is tied to the magnetic field...
  • any mention of a certain bullshit hollywood production with the shittiest scientific basis for a film since the neverending story will result in death. of the poster. thanks for not getting yourselves killed.

  • no magnetic field, really? (Score:5, Insightful)

    by Bastian ( 66383 ) on Monday April 12, 2004 @08:12PM (#8843076)
    I'm no geologist, but it seems strange to me that in the process of a magnetic field reversal the earth's magnetic field would just go away for a few thousand years. Wouldn't the field just rotate over time, so that the magnetic north pole continues to drift until it is near the geographic south pole?

    • Re:no magnetic field, really? (Score:5, Informative)

      by JGski ( 537049 ) on Monday April 12, 2004 @08:27PM (#8843156) Journal
      It's apparently far more complex.

      From what I've read on the web and seen on a PBS Nova program about the subject: during a flip the Earth's internal dynamo goes from ordered to chaotic. The movements is not just is a straight bee-line to the opposite side. The North pole, for example, has been drifting even of the last 30 years toward the south east. The field strength declines substantially and the magnetic fields change from bipolar (two poles: north and south) to multipolar ("poles" coming out of any which direction - the "Southern Anomaly" in the south Atlantic is apparently believed by some to be the onset of a tripolar field). When the actually collapse is imminent, these poles start moving quickly, as much as degrees of latitude or longitude per day or week.

    • Re:no magnetic field, really? (Score:5, Informative)

      by therealmoose ( 558253 ) on Monday April 12, 2004 @08:34PM (#8843214)
      No, it's quite complicated (somewhat like a fluid system). Regions of the field spin around, strengthen, weaken, and drift around in complex 3d patterns for thousands of years according to the models (confirmed by geological finds). The net effect is that the field is significantly weaker (due to the lack of a uniform makeup, in part) and in some regions, some of the time, effectively nonexistant. It is not sufficient to deflect the radiation that it currently does while 'flipping'.
      • ...yet there are records stamped in lava of massive (in excess of a right-angle from the PoV of the region sampled) pole-swing which took place in 90 minutes or less.

        Mercury has a reasonable magnetic field, yet shouldn't be large enough to still have much fluid inside. Mars has negligible magnetism, yet is many times larger than Mbeercury. Venus is in many ways comparable to Earth, yet no serious field. It can't be the retrograde spin, because Uranus spins on its side and has quite a strong field - lateral

        • Re:You sound as if you know what you're on about.. (Score:5, Informative)

          by CheshireCatCO ( 185193 ) on Monday April 12, 2004 @10:07PM (#8843763) Homepage
          Appart from the general off-topic nature of that rambling post, it shows a poor understanding of the data, unless someone has utterly failed to clue me in on some breaking developments in astronomy. (Possible, but my collegues like talking about their work too much for me to think that that's likely.)

          You'd better show me a paper that suggest that gravitational redshift doesn't happen, because I have yet to hear of it. And since that'd be Nobel-quality work, showing that GR breaks down (where it should hold up), I'd be surprised if the research happened. In fact, I attended an entire comps on GPS. While GR was certainly discussed, since they need to take it into account for GPS to work, no corrections to that theory were mentioned. Seems sort of odd that the speaker would talk about GR without mentioning that it broke down.

          And I have yet to see a steady-state model that matches the data very well at all. The whole "cosmic microwave background" thing is hard to get around. Since I just attended a lecture by a well-known cosmologist and he didn't say a word about the Big Bang being "broken", I will have to once again ask you to back up your rather grandiose assertions.

          As for planetary magentic fields:

          There are lots of ways that Mercury can have a fluid core, still. The most commonly argued one is to have more sulfur mixed in. This should lower the freezing point sufficiently to keep it molten still. It's also worth noting that Mercury has an unusually large core for its size. This might play in to things.

          Mars lacks a global field (today) because it has almost certainly cooled off too far. (If we assume the same composition as the Earth, anyway.) This is supported by the lack of ongoing volcanism or tectonics, which also require a molten interior to proceed. However, in the past Mars *did* have a global field. This is quite consistent with the theory, since it would have been warmer inside.

          As far as I know, no one has ever suggested that Venus's retrograde spin is the cause of the lack of a magnetic field. That's fairly silly, since the field doesn't know which "way" the planet is spinning anyway. (Magnetic field on other planets are can be found oriented both ways with respect to their planets' spins and we know that Earth's field has changed direction.) However, the astute person would have noticed that Venus does spin very, very slowly. This would generally lead to a small or non-existant field, since planet spin is thought to be tied in to the dynamo process. (There's a strong correlation between field strength and planet's angular momentum, for example.) Of course, Mercury only spins 3 times faster, but that's still something.

          I'd also love to see your proported research showing field changes if 90 minutes or less. How in the heck do you DATE to that accuracy? You can't, unless you pretty much just watched it cool. (In which case, why didn't every compass on Earth notice the switch?)

          No one is saying that we totally understand cosmology or magnetic dynamoes. But to suggest that we're "whistling in the dark" is to down-play the wonderful and careful work of far too many people to let you get away with saying that here. We might not have the details all down, but I'd say that we're doing alright on the theories.

          • someone has utterly failed to clue me in on some breaking developments in astronomy

            Think Copernicus. Tell me of any seriously revolutionary idea which you know was accepted with open arms by all.

            You'd better show me a paper that suggest that gravitational redshift doesn't happen, because I have yet to hear of it.

            Of course not. You wouldn't hear good things about Linux in any Microsoft-sponsored presentation either, and wouldn't expect to. If you don't expose yourself to anything but orthodox dogma, w

            • Re:Yeah, yeah, yeah... (Score:3, Insightful)

              by BerntB ( 584621 )

              Tell me of any seriously revolutionary idea which you know was accepted with open arms by all.

              But the fact that some geniuses were laughed at does not imply that all who are laughed at are geniuses. They laughed at Columbus, they laughed at Fulton, they laughed at the Wright brothers. But they also laughed at Bozo the Clown.

              -- Carl Sagan

              Also note that there are quite a few more clowns than very good and misunderstood scientists. :-)

              Etc, etc.

              Go read a book on the scientific method.

              • But the fact that some geniuses were laughed at does not imply that all who are laughed at are geniuses.

                I suppose that, being SlashDot, it's a point that constantly needs to be made.

                Go read a book on the scientific method.

                Done. Now go and see how it works in real life. You're speaking to a bloke with four qualified scientists that he knows of in his family tree, and several more as friends.

                • [I have read a book on the scientific method] Now go and see how it works in real life.

                  Maybe you have. But you wrote:

                  Tell me of any seriously revolutionary idea which you know was accepted with open arms by all.

                  Academics quarrels and questions everything. It's not only their personality but their jobs...

                  You can't find any idea about anything that was accepted by everyone.

                  Maybe you have read up on the math and the subjects you discuss enough to have a well developed opinion on why the resea

                  • You can't find any idea about anything that was accepted by everyone.

                    Missing word: revolutionary.

                    As long as the new thing is close enough to safe orthodox dogma, it runs a fair risk of being wildly accepted by everyone who matters.

                    It's only as it tends towards truly useful in breaking the inevitable ossification that an idea (and by contamination its originators and supporters) starts getting daggers in its back.

                    • As long as the new thing is close enough to safe orthodox dogma, it runs a fair risk of being wildly accepted by everyone who matters.

                      Uhm, didn't you claim to know some academics? :-)

                      Yes, the old inside/outside of a paradigm discussion.

                      Generally, most new ideas fail -- no matter how smart the people that put them forward.

                      To apply a simple heuristic:
                      If you really understand everything better than anyone else you would be to busy to post to /.

                      I have nothing more to say here.

                      (-: If my heuristi

                • Let's try to minimize the fissure between emic and etic practices, okay? I see no reason to further accentuate them.
            • In other words, you have nothing that you can put forth to show what you're talking about. You're resorting to accusing scientists of censoring your results, when in fact we'd be all *over* something revolutationary and new. History is full of examples of this: GR was generally quickly accepted. So was quantum mechanics (the best and brightest young physicists flocked to it in the early part of the 20th century). The Giant Impact model of the Moon's formation took hold quite quickly, too. Sure, we don'
              • In other words, you have nothing that you can put forth to show what you're talking about.

                So says the man who has not read a word of the two references cited in the GP?

                Go back and read them, then try again. Meanwhile...

                we'd be all *over* something revolutationary and new

                As long as:
                • It wasn't too terrifyingly different (ie, not too different from our current worldview - or to put it differently, it has to be modestly "revolutationary and new");
                • we thought we had a plausible answer to quench it with, or at least weren't more than a hairsbreadth away from figuring it out ourselves;
                • we don't have to rework too much existing theory if we accept it
                Without those qualifiers, your assertion is codswallop.

                The Giant Impact model of the Moon's formation took hold quite quickly, too.

                Pity it's still under heavy dispute then, isn't it? (-:

                You might also want to think about a couple of decades in terms of "quickly accepted" and the difference between acceptance of a theory de novo when contrasted with the acceptance of a theory which has already been abuilding for years.

                Maybe it's just me, but I rate the functionality of an idea far more highly than its peer acceptance rate.

                usually you'll find a number of them quickly jumping into the new field. (That's how you make a name for youself, after all)

                I call bullshit. That's how you get fired, or at least get a black mark on your research record which cripples your career.

                The "heroes" adopt incremental improvements ahead of the pack. The vast majority of true pioneers, willing to avidly and openly explore genuinely revolutionary ideas, get pilloried for years, sometimes decades, and many die scorned only to have people come around to an understanding of what they were doing long after they're safely buried.

                J Harlan Bretz, for example, was sidelined and scorned for forty years before his ideas were even investigated, and for the justification of hearing one of the investigators who was finally cajoled into actually taking a trip out to look at the Washington badlands for an actual look at the rocks exclaim "how could we have been so blind?"

                His sin? Heresy. His theories, which are now mainstream and shatteringly obvious in hindsight, challenged the dominant orthodoxy in geology. They sailed too politically close to ideologically sensitive areas, to "political" boundaries which have absolutely nothing to do with science and everything to do with philosophical prejudice, and which still exist.

                It's a brave and stubborn scientist who candidly investigates truly novel theories.

                Now get off your ass and read, boy!

                • Maybe it's just me, but I rate the functionality of an idea far more highly than its peer acceptance rate.

                  It is just you. Personally, I look for theories that are consistent with the evidence.

                  I call bullshit. That's how you get fired, or at least get a black mark on your research record which cripples your career.

                  I call prove it.

                  The vast majority of true pioneers, willing to avidly and openly explore genuinely revolutionary ideas, get pilloried for years, sometimes decades, and many die scorned onl

          • However, the astute person would have noticed that Venus does spin very, very slowly. This would generally lead to a small or non-existant field, since planet spin is thought to be tied in to the dynamo process. (There's a strong correlation between field strength and planet's angular momentum, for example.) Of course, Mercury only spins 3 times faster, but that's still something.

            This had me giggling. (-:

            OK... so if Mercury spins 3x faster, it should have roughly 3x, or 3^2x the field depending on how

            • "OK... so if Mercury spins 3x faster, it should have roughly 3x, or 3^2x the field depending on how your dynamo works?"

              Well, it isn't linear, for one thing. Why do you assume that it is? Do you know anything about dynamo theory? (The non-linearity is what makes it such a thorny field in the first place, after all.)

              "One of the few forces which explain nearly all of the features of Valles Marineris is lightning"

              I'm not sure that this even deserves a reply. This is just too bizarre. Valles Marineris is

              • Well, it isn't linear, for one thing.

                Neither is my car's alternator. But linear should be in the ballpark, and it's an order of magnitude off. And you haven't even spoken to my observations about the variety of compositions, temperatures and spins, and in particular to the complete absence of systematism amongst them.

                Valles Marineris is way to big to be carved by lightening.

                Cloud-to-ground lightning, I agree. (And by the way, Konqueror spellchecks within web forms starting from the version which come

                • Why have you spent so much time filling your brain with 'facts' that you don't actually understand (in some cases by your own admission)? Oh, I thought I'd also point out that someone else seems to have thought the same thing as me, hacked into your account, and placed an apposite quotation in your sig. I strongly recommend that you read it.
            • Ha ha ha ha ha ha ha ha ha ha ha ha ha ha ha ha ha ha ha ha ha .........

              That's the stupidest thing I've ever heard. I'm not certain why you'd need a gigantinormous lightning bolt to explain loose rock on the surface of a planet which bears the scars of millions of impacts. And since planetary surfaces tend to act as equipotential surfaces, what sort of bizarro explanation do you have for a lightning bolt that travels horizontally for 4000 km? You claim that "water, sand and tectonics don't explain much

            • Mars is a lot smaller. Small objects loose internal heat faster because of a higher area:volume ratio. Mars shows extensive evidence of having lost its internal heat. Some evidence suggests it still has enough to melt ice and produce steam, but...

              Venus shows extensive evidence of still having at least some of that internal heat, and displays "recent" volcanic activity (much more recent than Mars at any rate, and it's atmosphere is comprised mostly of common volcanic gasses) on a nearly planet-wide scale.

              N
              • ...if what you say about rotation and cooling is true and relevant, it should also apply to Mercury - and doesn't. True, I believe - relevant, less so.

                The gas giant "reconciliation" is just a guess, not tested, not known to be workable. Considerably less definite than the actual measurements.

                When I talk about lightning, I don't have atmospheric storms in mind. They don't have the energy density to do much, and it's not as if Mars has an atmosphere to brag about anyway.

                However, if the discharge came from

          • I'd also love to see your proported research showing field changes if 90 minutes or less. How in the heck do you DATE to that accuracy?

            You don't. See, for example:

            Mankinen, E. A., Prévot, M., Grommé, C. S. and Coe, R. S., 1985. The Steens Mountain (Oregon) geomagnetic polarity transition, 1. Directional variation, duration of episodes, and rock magnetism. Journal of Geophysical Research, 90:10,393-10,416.

            [ditto] 2. Field intensity variations and discussion of reversal models. Journal of Geoph

            • Actually, if you pay closer attention, the third paper only says that they COULD be seeing a rapid shift. Not that they are. The authors themselves are pretty hesitant to claim what you're jumping on so readily.

              And, as you note, most geophysicists don't think that those rocks are suggesting what you're accepting as fact. The problem with real science is that the data aren't always as clear cut as in the labs you do in classes.

              Interestingly, this is the first time you've posted anything with substance.

              • You're right, there is evidence there for a rapid reverse. Not *good* evidence, but evidence.

                Good evidence. It's been challenged, as you might expect, and reviewed and checked by the authors themselves in anticipation of this, and re-done in several different ways and the answers always come up smiling. Peer review has pounded on it, hard, and failed to break it.

                In any event, you're either jerking my chain or you're a raving lunatic.

                My turn to come off at a corner, I guess.

                I present evidence, and th

          • One thing about Venus: I've never heard it say that retrograde spin is related to a lack of a magnetic field, but I have seen a simmilar suggestion: That it's unusually slow spin (243 days - although it's "day" is only 116 because it actually orbits faster than it rotates) doesn't stir up enough motion in its liquid core (if it has one, doesn't say anything on the page where I got the rotational speed) to produce a magnetic field.
        • I know barely enough to clearly discern why big-bang is broken...
          My current favourite is one which features a changing ZPE...
          And what, pray tell, made it your favorite? The fact that it came packaged in a pretty box, the pleasant aroma that it gave off, or maybe just the fact that when you wear it it gives you warm fuzzies?

        • Wow (Score:2)

          by barakn ( 641218 )
          You managed to stay on topic for only 20% of your rant. Sticking with magnetic fields for the moment.... Another poster has already pointed out quite reasonable explanations for the magnetic fields of the terrestrial planets. "It is quite clear that our current ideas about planetary magnetism are at best whistling in the dark" because we don't know enough about the interiors of the planets, not because of fundamental flaws in physics theories as you seem to imply. A recent model [maths.org] has explained the comple
    • I'm nervous pointing this out, but in our E&M class we were directed to a pseudo-science web site (our professor assures us that the presented pseudo-science violates certain well understood principles).

      But among the dozens of pdf's this web site provides, one is on the ocean rift polar flips.
      rift.pdf [distinti.com]

      In short, what it says is that as the mid-atlantic rift rips apart, hot magma comes to the surface, and that liquid is a lesser magnetic conductor (lower permeability) than the pre-existing high iron-c

      • Re:no magnetic field, really? (Score:5, Informative)

        by CheshireCatCO ( 185193 ) on Monday April 12, 2004 @11:52PM (#8844479) Homepage
        "None the less, I tend to like simpler solutions than a chaotic tri-poled earth magnetic field, or whatever currently is the explanation."

        Yes, but surely you like an explanation that is *accurate* even more than you like one that is simple. I mean, I can think of simpler explanations for the striping quite easily. (Like, "There is no striping. These are not the droids you're looking for...") But they probably wouldn't reconcile with the various data very well. :-)

        (Also, magnetic fields fall off as least like 1/r^3. The lowest order moment is a dipole, remember. At least until someone finds a magnetic monople, anyway.)

        To get at the article you linked:

        First of all, it suggests that the planets' fields are all oriented the same way with respect to their spins. Not true. See my post, above. Jupiter's field is oppositely oriented to that of Earth, for example.

        It goes on to "point out" that Uranus's field is aligned with it's odd spin vector. Surprisingly little research with Google would have shown that to be very wrong. Uranus's spin and magnetic field axes are about 60 degrees apart. That's no where near alignment.

        He (I'll assume that the author is male) procedes to blame large amounts of cobalt and iron in Earth's crust for the slightly off spin axis magnetic field axis. Large amounts? The overwelming majority of Earth's iron is in the core or mantle, not the crust. What is in the crust is fairly evenly distributed. It's hard to imagine that the symmetry is broken that much, isn't it? (Sorry I don't have the raw numbers for the distributation, but I doubt that anyone has worked it out.) But if the iron in the core wants to direct the field along the spin axis, how is the miniscule amount of iron in the crust going to "redirect" that field significantly over global scales? (Sure, you've got a bigger lever-arm at the crust than the core. But only by a factor of a few. We're being told that that offsets the massively higher concentration of iron in the core.) Also, why is Earth's field offset as well as titled? (No lever-arm helps you with that one.)

        Another interesting error is the (apparent) assertion in the tidal breaking section that Earth will eventually spin 1/28 as fast to match the Moon's orbital period. That's half true, we will match the Moon's orbital period in about 5 billion years. (Just in time to be destroyed by the Sun's red giant phase. Yay!) But a simple knowledge of conservation of angular momentum tells you that we won't be spinning once every 28 days. It's more like a 89 day period, if you work it out. (Funny how he can use conservation of energy to apparently bolster his case when he wants to, but doesn't know what conservation of angular momentum is. While both are adhered to, with the latter it is much harder to "fake" a violation.)

        Next up... mass extinctions. He claims that palentologists have determined that they (the extinctions, not the palentologists) occur every 32 million years. Hm. About five mass extinctions in the history of the Earth (the last 65 million years ago) are known (http://www.bagheera.com/inthewild/spot_massextinc tions.htm) spanning back 440 million years or so. That's 380 million years and 4 intervals between them. Quick math check... I get that that's one every 95 million years. (Is that what you get, too?) For proving that exctinction events aren't caused by impacts, that's pretty weak. (Based on the cratering record on the Moon, mainly, the calculated interval between mass exinction causing impacts is about 100 million years. Roughly speaking.)

        Next bit of funniness. He claims that "Therefore a reversal in ion polarity would indeed reverse the Earth's magnetic field;" and then goes on to try to show that this is silly. Which is a strawman, since I don't know anyone who asserts that the ions will reverse polarity. How do you get ions to reverse polarity?? Unlike in chemistry, ions in astronomical contexts are essentially
        • I enoyed your rant, but this one in particular amused me:

          Uranus's spin and magnetic field axes are about 60 degrees apart. That's no where near alignment.

          He [...] procedes to blame large amounts of cobalt and iron in Earth's crust for the slightly off spin axis magnetic field axis.

          He forgets, of course, that as well as being magnetic, it's also heavy and enough of it to influence the magnetic field would produce an effect not unlike your car's harmonic balancer disintegrating.

          I don't know whether peop

          • "Yeah? Which part of the Moon did you have in mind? Poles? Maria? Farside?"

            Um, the whole thing... the cratering rate appears to have been fairly constant over the past 3-4 billion or so years. Thanks to the fact that the Moon has areas of different ages, we can figure out the cratering rate. (You date those surfaces with those nifty rocks that the Apollo astronauts brought back.)

            Thanks for asking, though. I suggest reading "THe New Solar System" next time *before* you assume that we're making stuff up.

            • the cratering rate appears to have been fairly constant over the past 3-4 billion or so years.

              References? Comments on the delta between farside and nearside? Comments on ghost craters?

              Serious question: why does my replying bother you?

              It doesn't, I'm delighted by it. Seldom are people serious enough to make me think about my replies. Sad but true. Welcome to the elite.

              However, I get the distinct impression that I'm pushing you near the edge of your resources sometimes. You're asking me for references

        • How do you get ions to reverse polarity??

          Normally you'd begin by modifying the deflector dish.

        • Finally -- and this is only because I'm tired of debunking this nonsense, not because he is done spouting it here -- materials don't "focus" magnetic fields as he describes. He makes it sounds like metals suck in field likes so that they pass through them. Field lines stay tied to whatever electically charged material they run through, but that's about it. You can superimpose fields, to be sure, but you can't just alter a field like without affecting the source.

          Look up FEMM and play around with it a littl
          • I didn't say shielding doesn't occur. Of course it does. Materials can definately alter the paths of field lines that would otherwise pass through them. (Superconductors, for example, actually expel fields, up to a point.)

            I said that the presence of iron doesn't magically reach out and grab field lines, dragging them through the metal, when they were originally running high above the Earth's surface. That's what this article was implying iron in Earth's crust was doing. Unless you know of a way of doi
            • Sorry I obviously didn't RTFA.

              Oh and BTW, Superconductors don't expel field lines exactly; they precisely resist all changes in magnetic fields; they are an infinite inductor. If a magnet is sitting on a superconductor when it goes critical, as the super conductor approaches critical it will become extremely diamagnetic, expelling field lines. When it goes critical, however, all field lines are trapped in place. This is where the standard magnet hovering over a superconductor spinning on its poles demo
        • He goes on to assert that charge seperation cannot occur (which is funny, since a child can do it in the lab with a peice of metal and a blowtorch held at one end) because we'd detect the powerful magnetic field from the electrostatics

          I wouldn't let blow-torch-wielding children loose in my lab, but I'd certainly let them separate charge by rubbing their heads with balloons. Or let them pet my cat.

          • Well, we frequently have to replace out Timmys in out labs, but we let the kids have blowtorches.

            In this case, the thermal gradient is the cause of the charge seperation, just like is believed to happen in the Earth. There might be loads of cats and amber rods, but that's not well-supported in the seismology data.
        • Next bit of funniness. He claims that "Therefore a reversal in ion polarity would indeed reverse the Earth's magnetic field;"

          My guess is he was watching Star Trek when he wrote that. Just imagine Leonard Nimoy saying it.

      • None the less, I tend to like simpler solutions than a chaotic tri-poled earth magnetic field, or whatever currently is the explanation.

        The sun provides an interesting example of polarity flips, which only take 11 years and thus are fairly well studied. The way it does it is different than Earth, as the sun's convective layer is what produces the field, and the convective layer extends to the surface. None the less, during the flip, the sun's surface sprouts many magnetic poles, almost always in pairs.

  • I didn't see any mention of a loss of the Terrestrial Magnetic Field in the article, only a change of polarity. The two (polarity reversal, and field loss) an not necessarily equivalent, at least over long time scales.
    • From what I read, it sounded like the time of "no magnetic field" was the time during the reversal process - after the reversal is over, everything will be just fine, it's the process that we're worried about, where the magnetic fields aren't quite aligned like they are now, but scattered in a way to diminish the protective effects we get from it.

  • not to worry! (Score:4, Funny)

    by Tumbleweed ( 3706 ) * on Monday April 12, 2004 @08:17PM (#8843107)
    I'm sure the Highlander will invent a shield to protect us when the time comes.

  • Dipole to quadrupole to reversal... (Score:5, Interesting)

    by lcde ( 575627 ) on Monday April 12, 2004 @08:27PM (#8843160) Homepage
    I can't find the article on google right now, but the last time i read about this in between the reversal of earths magnetic pole it turns into a quadrupole or higher order for a couple of hundreds of years then it finishes.

    Still we won't lose our magnetic field unless our core solidifies, but a field reversal or a higher order magnetic field will allow different polorization of solar winds and other EM noise that would be different that what we have now. We also might not be as well protected against the solar flares during the sun's cycle.
  • Article has next to nothing to do with the blurb.. maybe the Slashdot "editors" should RTFA before posting.

  • mutations? (Score:4, Funny)

    by nomel ( 244635 ) <turd&inorbit,com> on Monday April 12, 2004 @08:42PM (#8843282) Homepage Journal
    Maybe all the particles from the sun that will hit us will cause mutations! Maybe that's what happened before.

    I can see it now...
    "Play hard, play tough. Nike lead lined athletic wear."

    • "Play hard, play tough. Nike lead lined athletic wear."

      Heh. If Nike could come up with a substance that blocks magnetic fields, they could retire from the clothing industry. But playing along with your premise, the ads would probably be pitched at the Entitled Rich:

      Sign up now for Dr. Mengele's Sure Protection Of Reliable Traits and assure the survival of your gene line! Qualified applicants only. Vee vill determine who iss qvalified."

    • Maybe particles from the Sun that have hit us have already caused mutations! Maybe without genetic mutations we all wouldn't be here!

      Insightful indeed...

      • Re:mutations? (Score:3, Interesting)

        by nomel ( 244635 )
        yes! Looking into this a little more, the time figure are close...

        Perhaps this explains the jumps [berkeley.edu] in evolution observed every 100,000 years or so.

        from this article [sciam.com]
        "The time between magnetic reversals on the Earth is sometimes as short as 10,000 years and sometimes as long as 25 million years; the time it takes to reverse is only about 5,000 years."

        Someone should look into this!

        Get ready for a new body! Woohoo! :p

        .

  • Can GPS substitute? (Score:1, Interesting)

    by Thinkit4 ( 745166 ) *
    So our compasses would be screwy. Couldn't we use GPS to give direction?

    • Re:Can GPS substitute? (Score:5, Interesting)

      by bluGill ( 862 ) on Monday April 12, 2004 @09:03PM (#8843400)

      Learn to navigate without a compass. I live in an area with many iron deposits, we learned long ago that a compass is not a reliable tool for navigation. We learn other tricks. (Starts at night, guesstimate the time and use the sun during the day). Combine that with knowing about what the land should look like and you can get close enough. Not as easy or are reliable a a compass in other areas, but it works.

  • The poster is a moron (Score:4, Insightful)

    by psyconaut ( 228947 ) on Monday April 12, 2004 @08:52PM (#8843337)
    "That's a long time without a protective magnetic field".

    Actually, haven't you wondered how life existed during previous flips? We don't lose our protection....it's polarity shifts....

    -psy

    • Re:The poster is a moron (Score:4, Insightful)

      by Phexro ( 9814 ) on Monday April 12, 2004 @10:45PM (#8844032)
      Thank you, I was about to post something similar.

      It's a long time to us puny humans, but it's the blink of an eye in the planetary timescale.
      • I think people think that the magnetic poles are like a battery that can only flip betwene positive and negative...they are constantly moving (magnetic north has strayed to Russia, but is currently in Canada), and they vary in strength.

        And, as you so rightly said: we're far too insignificant to be wiped-out by something of cosmic proportion or scale :-)

        -psy

  • are we sure Halliburton (Score:5, Funny)

    by morelife ( 213920 ) <f00fbug@post[ ]O ... t ['REM' in gap]> on Monday April 12, 2004 @08:54PM (#8843362)
    or one of its subsidiaries isn't doing this remotely?

  • Goodbye Van Allan Belt, Hello Cosmic Rays (Score:5, Informative)

    by StateOfTheUnion ( 762194 ) on Monday April 12, 2004 @09:26PM (#8843542) Homepage
    The original linked article isn't very informative. There will probably be a period of no significant magnetic field while the field is reversing . . . Here's [psc.edu] an article about a simulation that to everyone's surprise, actually predicted the reversal.

    Goodbye Van Allan Belt, Hello Cosmic Rays . . .

  • Way Overdue (Score:5, Funny)

    by jazman_777 ( 44742 ) on Monday April 12, 2004 @09:35PM (#8843592) Homepage
    The magnetic field flip, the super-volcano in Yellowstone, the San Andreas Fault, the demise of SCO. Have I missed anything? A Red Sox or Cubs World Series winner?
  • welcome our new cosmic ray overlords! (Well, for at least a couple thousand years)
  • Without a magnetic field, we will have (comparatively) little protection against gamma rays from the sun. There are only 3 solutions to living on earth without a magnetic field:

    1) Living above ground with SPF 10000 sunscreen being constatly applied
    2) Living above ground with a Class 5 hairiness - like those seen on Steve Allen and CowboyNeal
    3) Living below ground

    Since I hate putting on sunscreen, option 1 is ruled out. Since I don't like Steve Allen, option 2 is also ruled out.

    Thus leaving us with option

  • punctuated equilibrium (Score:5, Interesting)

    by orn ( 34773 ) on Tuesday April 13, 2004 @01:37AM (#8844971)
    The fossil record shows that the Earth goes through periods of time where there is an incredible amount of speciazation - new critters pop into being very quickly. I've read other stuff that suggests that this is simply due to the die-offs: since there's a niche available, something moves to fill that niche.

    Could this be a contributing factor or even a causative agent? The normally low error rate in genetic reproduction takes a big spike due to more particles getting through the Van Allen belts?


    • > Could this be a contributing factor or even a causative agent?

      IIRC, someone has looked into this and found that there isn't any correlation between the reversals and die-offs.

    • Re:punctuated equilibrium (Score:2, Interesting)

      by Anonymous Coward

      Could this be a contributing factor or even a causative agent? The normally low error rate in genetic reproduction takes a big spike due to more particles getting through the Van Allen belts?

      It could be even simpler than that. Evolution is essentially the movement towards a creature that is better suited towards the environment it is in. When that environment changes rapidly, there will be loads of ways in which a population could differentiate itself to become a better match.

  • years (Score:1)

    by Googo ( 695955 )
    2000 years, 10000 years, its all the same thing. Its just another day at the park.

  • Magnetic GPS? (Score:1, Insightful)

    by Anonymous Coward
    I'm intrigued. If animals can tell exactly where they are by sensing the magnetic field's "texture" [http://www.pbs.org/wgbh/nova/magnetic/animals.htm l], shouldn't GPS make use of that too? It seems to me that such technology would be a lot cheaper than sending sattelites to the orbit.
    • I think that works for animals who are looking for general areas, or general "feelings". But if you are trying to pinpoint a location down to seconds, I doubt highly that a magnetic field which is constantly shifting and moving around would be of much use to GPS.

  • Great! I need help with my tan...
  • The article neglects to explain how this is the fault of the Bush administration.

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