Magnetic Poles May Be About To Flip 721
AGD writes "According to the Guardian, Earth's magnetic field - the force that protects us from deadly radiation bursts from outer space - is weakening dramatically. . The article goes on to say 'Earth's magnetic field has disappeared many times before -- as a prelude to our magnetic poles flipping over, when north becomes south and vice versa.'"
Re:I remember seeing this on sightings years ago.. (Score:3, Insightful)
'Could be in the next 1000 years', according to the article...
A little less concerning :-)
nope (Score:5, Insightful)
The change will be gradual, with about a thousand years of no field. But I wont worry about it. There is no precedent of extinction due to pole reversal.
If primitive beings could survive so can we. There must be some mechanism by which the earth wards of the effects. Maybe some thing in ionosphere. It kind of difficult to beleive that something which couldnt make anything extinct 250000 years ago will do it now on a species which spends most of its life under radiation shields(read buildings)
Will life survive again? (Score:3, Insightful)
What can humans do, besides burrowing or mutating?
Suddenly, global warming (the artificially-induced kind) doesn't seem like that big of a long-term threat.
Re:nope (Score:4, Insightful)
you mean "we, the people living in industrial countries"?
Re:Get real! (Score:5, Insightful)
In (slightly) more scientific terms, the advances we've made since those cavemen times are built on the premise of incremental change - we talk of "advances", ie: building on the past to get farther. Take away the foundations (communications is the major one, I guess, direction finding, etc.) and see how well everything that depends on them copes. Consider how an economy might react to (for example: the collapse of air traffic), and the subsequent secondary effects. None of this was even slightly worrying to the caveman, but our world is immensely dependent on excellent long-distance communications.
Yes, we have a far and away more complex civilisation than a caveman ever dreamed of. This is a weakness, not a strength. The payoff comes from what we can do with that technology, but if you remove that, you end up with a lot of hungry people in a small space...
I concur with the physics, btw, but you're really overestimating the resilience of our civilisation.
Simon.
Re:Get real! (Score:4, Insightful)
The same goes for communications with the exception of possible solar flare interference periodically.
It seems to me that while the pole disappearing/changing could cause significant change it isn't a showstopper for much of anything except the use of all current compasses and perhaps sunbathing.
Re:Umm (Score:3, Insightful)
Volcanic activity has fucked with the atmosphere of the planet more than man ever will.
Add into that shit falling from space plus other natural phenomena and it makes our little bump in the road of existence pretty meaningless.
Sound familiar? (Score:5, Insightful)
Breaking news! Scientists predict imminent destruction of humanity! Film at 11.
It occurs to me that major movie studios have a lot of media contacts and experience in influencing the stories that go down the wire. I'm not saying that there isn't good science behind this, just that perhaps the news media are being encouraged to run the angle that grabs reader's attention rather than present a balanced view. Remember that New Scientist isn't "not for profit", it's a commercial venture.
Rubbish (Score:5, Insightful)
Whoa
'On Earth, it will heat up the upper atmosphere and send ripples round the world with enormous, unpredictable effects on the climate.'
Arh! I think it will make some lovely daytime aurora, and generally play havoc with electrical equipment.
Mars is exposed to this kind of solar radiation, but it's atmosphere stays fairly chilly! The only solar radiation that seems to affect its temperature is the infra-red kind.
I'm willing to bet this article is nothing more than pre-hype for the movie The Core.
A lot of people don't grow food and they survive (Score:5, Insightful)
Take a look at the early Industrial Revolution Cities in England. So overcrowded a plan was needed.
The solution : criminalisation of poverty. That way the poor could be killed or transported.
The sudden loss of computing would be totally devastating in the short term. And for mnay of us that could be as long as we live.
Re:Get real! (Score:5, Insightful)
Direction finding is becoming more and more based on GPS than anything. GPS has nothing to do with the magnetic field. It disappearing wouldn't cause it to fail at all
It's the earth's magnetic field that diverts the solar wind away from us. Without it, the GPS satellites would almost certainly be destroyed by the increase in ionising particle flux. Along with all the communications satellites.
Re:The HAB Theory (Score:3, Insightful)
The Earth's magnetic field is well known to wander about. Apart from the fact that Magnetic North is currently moving at a measurable speed, lines of aligned particles of iron in rock strata show a clear history of magnetic pole reversals.
The Earth's axis of rotation, on the other hand, is about as fixed as anything can be. The angular momentum of the rotating Earth is huge; you'd need an equally huge external force to shift it. The Earth's magnetic field is puny in comparison, and can't affect rotation in this way.
Apart from the fact this this "theory" contravenes the laws of Physics, there is no geological evidence to support this (frozen mammoths don't count!) and huge amounts of evidence to counter it. All the recent ice ages occured in the (current) north and south latitudes, for example. There are no signs of the sea inundating the land for thousands of miles, which is what would ensue in such a disaster. Plus, there are fragile stalactites that have formed over many thousands of years, and which would shatter if something this dramatic had ever happened - but which are perfectly intact.
Re:Get real! (Score:5, Insightful)
For the record, I often think it a stretch to describe this mess as a 'civilization' anyway. But to address your point--I think that the problems caused by this occurrance will be alleviated somewhat by it's relatively slow onset. Sure, the poles flipping is a very rapid thing on geologic timescales, but we're still talking decades or more.
Communications won't collapse--most long-haul lines are based around fibre now, which is essentially impervious to solar radiation. Satellites infrastructure might take a bit of a hit, but I don't see the iminent collapse of the GPS system. (Since the U.S. military really can't do without it, they'll find a way to keep it working. Kind of a hand-waving argument, but you can bet your ass that they'll get whatever appropriations they want from Congress.) Retaining GPS and transoceanic fibre will mean that international finance and trade will be pretty much unaffected.
Climate change is a different beast altogether. Nobody knows exactly what form it will take, if it happens at all. The world already overproduces food--we just don't distribute it very well. I suspect that we will see exactly what we've seen for most of this century--the developed world will survive in relative comfort, while Third World nations willl starve.
As to health effects--again, a big question mark. It depends on dose of solar radiation, but I'm heartened by the fact that these flips have happened fairly frequently without being accompanied by mass extinctions. Cancer rates will go up somewhat. Wealthy nations will probably develop preventive medicines to cut down on the effect.
In short, day to day life probably won't be seriously affected for most people. We'll get some weird weather, and have to develop some interesting technological solutions in some areas, and--oh, yes--low lying cities may have to build dikes or be evacuated. But that's about it. Not the end of civilizaiton.
Alternately, I advocate giving every person on earth a little bar magnet to carry around, along with detailed instructions as to how it ought to be oriented to maintain an artificial planetary magnetic field.
when you fit fit your data to a line... (Score:5, Insightful)
according to another article that somebody else linked above, (here) [newscientist.com] this conclusion isn't based on an ongoing survey of the earth's magnetic field over the last 20 years (as implied by the observer article), but rather on the comparison of current data to a single set of data taken 20 years ago:
But Ørsted is the first satellite to take a snapshot of the Earth's magnetic field for 20 years, and such scant data makes it difficult to predict future shifts.
so while this may make a great shock news story (or hollywood movie plot) it hardly seems like anything approaching significant scientific research worth getting particularly alarmed about.
Re:Get real! (Score:3, Insightful)
It's not all bad (Score:5, Insightful)
Source of the magnetic field. (Score:5, Insightful)
Sure we do. It's from dynamo currents caused by convection in the (liquid) outer core.
Magnetic field flips happen when turbulence grows enough to disrupt these patterns briefly.
This is why Jupiter has a much stronger magnetic field than Earth (huge liquid metallic hydrogen layer, and a very powerful internal heat source), and why the moon has almost no magnetic field (no liquid core; the only field is the one that was "frozen in" when the moon first cooled).
Re:Umm (Score:1, Insightful)
Volcanoes release huge amounts aerosols, but do not release large amounts of long-term, climate-altering gases. Nor does the shit falling from space. Though the vastness of the planet is humbling, the amount of CO2 released by human activity actually IS substantial, even on a planetary scale. (CO2 is a trace gas, so it is easier to meaningfully alter its concentration in the atmosphere than to do so for, say, nitrogen.) While global temperatures bounce around, CO2 levels are sweeping up in a near-perfect curve. One can argue whether humans are altering the climate, but there's no question we're increasing CO2 levels markedly.
Re:Business model (Score:2, Insightful)
Re:Get real! (Score:4, Insightful)
if anyone thinks that modern civilization will instantly collapse by the loss of GPS.... ther are the same morons that believed that Y2K was something to actually worry about.
science ... fiction? (Score:2, Insightful)
You can prove anything in a computer simulation. Whether it will happen or not is a totally different story, but for sure you can get funding if you tweak your variables properly. In geek terms, look at most video games where I can take a rocket blast and still survive, even though my hitpoints are lowered. Sure games are not true simulations, but neither are true simulations perfect, or often even close. It's a focus on one specific item with all the variables included to prove only that point. Believe the simulation worked; don't believe the simulation is correct.
All of a sudden some scientist picks something up, then a few more jump on the bandwagon, and then by the time we see the article, the whole theory is written in stone, even though the article contains very little fact -- for all we (the readers) know it could be pure speculation. The article makes bold statements and doesn't quote any proof. So take it with a huge grain of salt. How do we know that "Gauthier Hulot of the Paris Geophysical Institute" isn't regarded in his field with the same amount of controversy as the Drs. Igor and Grichka Bogdanov [nytimes.com] who are physicists that supposedly "don't know how to do physics" ?
And then the article mentions Hollywood!?! Yah, that sheds a lot of creditable light on the whole theory. Now are we are either: dealing with a Hollywood film house that picked up the idea from scientists, or scientists who want to ride on the tails of pop culture?
But we all love this dramatic stuff about the world ending, so it's no wonder that everybody -- whether scientist or check-out attendant, mathemetician or word perfect user -- jumps on the bandwagon. Enjoy your drama as we have all done here at slash/dot., but seek proof and fact before believing it will actually affect your real world. There are too many "important" people out there that believe they know what they are talking about or have agendas. It's hardly possible to spend all the needed time (as a reader outside the scientific fields) to gather the facts, proof, and knowledge needed in a world overloaded with information both true and false. Just find a couple articles from scientists that refute one another. That will help to provide a more balanced perspective. For example, read this message board [evcforum.net] for some real discussion about the theory at hand, instead of discussion about a newspaper article.
For example, you can get some real facts about Field Intensities During Polarity Transitions and Excursions [agu.org] linked from Message #15 in the discussion board.
The articles and theories are very important, but they still exist to be proven wrong, especially when they are relatively new.
does that word mean what you think it means? (Score:2, Insightful)
Reversals may only take weeks/months (Score:3, Insightful)
We may not die but... (Score:4, Insightful)
I am surprised no one has commented on the fact that the magnetic fields around earth protect the Earth from radiation that _damages_ electronics. When the sun has a solar flare, satellites are knocked out by the radiation. The only reason computers on the planet aren't is because the magnetic fields deflect enough of the radiation to make it harmless to electronics.
Yet, if we don't have a magnetic field to deflect the radiation, we end up with a completely different problem. A solar flare will likely be able to take out a majority of our satellites at first (if they aren't shielded, which most aren't to the degree needed.) Then with no field at all, the electronics on the planet are threatened by the radiation.
Likely very little will happen to us (considering it's just EM radiation mostly, and not radioactive isotopes.) But, There will definitely be a shift in computer construction towards better shielded designs. (because if there isn't, then... well, there won't be any computers working at all.)
worse than y2k? (Score:2, Insightful)
Hmm... I wonder if the programmers from the 70s had enough foresight to incorporate some protection against poleshift and excessive radiation.... I can't wait till someone starts marketing tinfoil shell casemods and making bank. "No really! You really really need it! Save your data! Can withstand up to one boiled atmosphere!"
Re:Double Nope (Score:5, Insightful)
I wouldn't worry.
Earth's magnetic fields do not absorb ionized radiation. They deflect it, to the magnetic poles. I.E. Same amount of energy hitting the planet all the time. In today's world, most of the ionized particles are deflected and concentrated to the polar regions. Net effect of a polar shift, atmosphere stays the same size. If anything earth's magnetic fields act like a giant vacuum cleaner, sucking up charged particles from 5 to 10 times the earths diameter. If the field goes away, no more vacuum cleaner effect, which results in LESS ionized particles hitting earth. (Global cooling, perhaps???)
We've had radar stations and plenty of other sensitive electronics in the polar regions for a long time. Even at concentrated radiation levels, most of it still doesn't get through our atmosphere (14.7PSI). 14.7 PSI is roughly equivilent to a 32 foot/~10 meter column of water. Plenty of shielding.
Re:Get real! (Score:4, Insightful)
Or cloud cover...
Re:Get real! (Score:3, Insightful)
I'm pretty sure we are
I won't
CO2 emissions from fossil fuel more than volcanoes (Score:3, Insightful)
Wrong. [bovik.org]
Re:Source of the magnetic field. (Score:2, Insightful)
I'll also point out that no one really knows how the planet's magnetic field is generated.
CT: Sure we do. It's from dynamo currents caused by convection in the (liquid) outer core.
Ok wiseguy. So you've got a forward model of MHD in spherical shells at high Reynolds number with perfect predictive power? Yeh Sure.
Look, even if you did, you'd have to have the initial conditions measured within like half a millimeter, at the formation of the earth, to deploy it successfully in predicting the next flip with any accuracy.
Right now, we're doing the best anyone can do with an inherently chaotic system (such as an MHD dual dynamo in planetary interiors) which is to make predictions about what will happen in the next time-step based on windowed autocorrelation of the time-series of measurements in the past.
But as far as really understanding the dynamos that generate planetary magnetic fields, i.e. having a mathematical model with demonstrated predictive power, no we don't.
If you do, we look forward to seeing your results at the next AGU meeting.
Re:Hrmm (Score:4, Insightful)
Either all this MS bashing is because of a lack of anything intelligent to say, or slashdotter's just aren't that creative or funny.
Re:nope (Score:3, Insightful)
I'm as worried about this as I am about the sun exploding. It's not likely to happen in my life, so I'll leave the problem to the /. crowd of the future to solve.
Re:Imposing our own field. (Score:3, Insightful)
Consider this construct to be similar in characteristics to a solenoid of radius 6.5e6 metres and length, oh, 4e6 metres. Because length is not substantially larger than radius, we can't just use the solenoid field equation, as field strength outside the solenoid would not be zero. But, if we assume the effective path for integration at the average field strength is a circle, we get about 4e7 metres. Let's be pessimistic and say 1e8 metres.
This gives:
B = 1.26e-6 * I / 1e8
Substituting in B = 1e-4 T (stronger than Earth's current magnetic field), we solve to get:
I = 8e9
So we need a sheet current on the order of 10 billion amperes in the solenoid (divide by the number of windings or mesh cables to get the current in one mesh cable).
The copper cable supplying power to your house has a rated current density of about 100 amperes per square centimetre of cross-sectional area. This is both using air cooling and adding a substantial safety factor. Using the same numbers, we get about 1e6 A/m^2 carrying capacity, giving us a cable of 1e4 m^2 cross-section (100m x 100m) required to carry *all* of the solenoid's sheet current. Parcel this out in smaller cables as you see fit.
Let's sanity check the cable numbers. Copper has a resistivity of 1.7e-8 ohm*m at 20 degrees C. A cable 4e7 metres long with cross-section 1e4 m^2 has a resistance of 1.7e-8 * 4e7 / 1e4 = about 7e-5 ohms. At 1e10 amperes, this gives a power dissipation of about 7e15 W.
To calculate energy stored, we need the inductance of the solenoid:
L = mu0 * A / length (1 winding)
A loop with radius 6.5e6 metres has an area of about 1.27e14 square metres. Therefore:
L = 1.26e-6 * 1.27e14 / 1e8
L = about 1.6 H
Stored energy is therefore:
E = 0.5 * 1.6 H * (1e10 A)^2
E = 8e19 J
Assuming 10 TW as our rate of energy transfer to the magnet, we need 8e6 seconds to charge the solenoid, or about 14 weeks. If our power supply is more modest (or if resistive losses are substantial), charging time is longer. However, it would still be accomplished within the span of a few years even in the worst case.
In summary, building and powering up the device is possible, though superconducting cables would make the construction much easier. As per my previous messages, you can certainly smelt enough aluminum for a resistive cable within a reasonable length of time. Producing the required amounts of high-temperature superconductor for a liquid nitrogen cooled cable is open to question. An ordinary metal cable could be made to superconduct at liquid helium temperatures, but maintaining the liquid helium envelope would consume a substantial amount of power (liquid nitrogen is much easier to make). Both methods use off-the-shelf technology that's already widely used in industry (LN2 for power transfer cables, LHe for magnets in MRI machines and particle accelerators).
Also, you would need to take into account the fact that the melted iron current in the earth's core would react to this field. Or, seen otherwise, if the pole were to flip, they'd rip appart you little wire around the equator in no time.
The solenoid described above actually stores more energy than the Earth's magnetic field does in *total*. If the entire core decided to do a back flip, the solenoid could take it. In practice, core disturbances are almost certainly much smaller - the core's field represents the balance point where power input matches resistive and other losses within the dynamo. The core's heat source doesn't have the ability to change the dynamo's state very quickly (field flips take thousands of years).
Satisfied now? It's easy enough to check my numbers.