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.'"
What about this Pole Shift? (Score:2, Interesting)
Climatic disturbance (Score:5, Interesting)
Re:Climatic disturbance (Score:4, Interesting)
Get real! (Score:5, Interesting)
Second, we have very little knowledge about how the poles are going to switch. There seems to be two options:
1. The poles are going to disappear, then reappear on opposite sides of the planet.
2. The poles will migrate over the face of the earth until they have effectively flipped over.
However, as geophysics usually shows us, there is a third, and much more complicated option, that is more likely. Simply put, the poles will weaken, and then split up into smaller magnetic zones, which will then wander all over the surface in an extremely complicated manner, and then coalesce on the oppposite sides. If you think this is a crackpot idea, you should check out past issues of Nature.
I'll also point out that no one really knows how the planet's magnetic field is generated. It is DEFINATELY not analogous to a regular bar magnet, because the core of the earth is much too hot to sustain magnetization of iron.
The HAB Theory (Score:1, Interesting)
When the poles shift in the novel, the best chance for survival is at the pivot points--locations halfway between the old and new poles.
Hollywood? (Score:5, Interesting)
A hand full of paragraphs on what may possible the End of Civilisation as We Know it (tm), ending in a halfway upbeat solution presented in a hollywood movie.
My first thought as that this simple was a planted story to sell the movie.
Re:nope (Score:3, Interesting)
Re:Get real! (Score:5, Interesting)
Cavemen were subject to any number of extinction threats that we don't really worry much about in our society. We aren't really worried about regional drought, flooding, forest fires, disease, predators, earthquakes, volcanoes, etc. Maybe worried is not the right word, but we don't face extinction because of these things. Also, the rise of technology has put us in a place where we have a chance of survival in places undreamed of by cavemen.
It's true what you say about a lot of hungry people in a small space, but in situations like that, a given population will max out at some saturation point where death- and birthrates even out.
Anyway, I wasn't really talking about our civilization's survival chance, just that "THE WORLD IS COMING TO AN END!" is paranoia, since it 's happened about 2000 times since our prehistorical ancestors crawled from the ocean.
Re:Down under... not any more! (Score:2, Interesting)
Re:Will life survive again? (Score:5, Interesting)
Re:..about time (Score:3, Interesting)
Presumably 'no magnetic field' recorded in the rocks actually means 'no single stable magnetic field'. Given discussions above about the mechanics of the actual flip I'd have thought it quite likely lots of small chaotic magnetic fields give adequate protection against any major catastophy
Re:Get real! (Score:2, Interesting)
I've met quite a few of them and the thought that they may be left after the rest of us are weeded has me quaking in my boots. I don't think I'm going to sleep tonight.
Re:Hollywood? (Score:2, Interesting)
"The solution, according to the film, to be released next year, involves scientists drilling into Earth's mantle to set off a nuclear blast that will halt the reversal."
Maybe it's because I'm not a Geophysicist, but I just can't even begin to see the logic of this. Usually you have to at least see the preview for a film before you can poke holes in it. Might be another one for the "Insultingly stupid movie physics [intuitor.com]" page ;-)
OK, after typing that my only guess is maybe they think the EMP could "push" the poles back???
Imposing our own field. (Score:5, Interesting)
It turns out to be feasible even today, though horribly, horribly expensive. You'd build a mesh of copper cables around the equator (or superconducting, but copper's losses aren't that bad for this). Then you'd slowly ramp up the current until you have a magnetic field comparable in strength to today's.
Ramping up would be slow because of inductive power storage. The current loop and associated magnetic field store a *vast* amount of energy, all of which needs to be provided in order to bring the field up to strength. The present power output of all electrical plants on the planet over a decade or so would do it, if I remember correctly, so this is feasible. The power cost to maintain the field, even with copper cables, is much lower; put, say, a 10% tax on electricity, and you've paid for the extra plants to feed the mesh.
You'd use a mesh instead of a single cable _because_ of the amount of stored energy. If you break the current path of an inductor, current flows anyways, arcing across the gap. This only dies down as resistive losses across the gap dissipate the power stored in the inductor. Think about this - all of the inductor's stored power is dissipated in one place (the break), and we're storing an awfully large amount of power in this current loop. If the loop was a single cable and this cable was broken, you'd get something in the range of a 10-gigaton yield at the point of breakage. A mesh provides many alternate current paths, so breaks from sabotage or just plain wear can be repaired safely (as long as you overspec the current rating enough to allow the other paths to safely take up the load).
A copper cable a hundred metres wide, or ten thousand one-metre cables, would do the trick. You might _have_ to use copper, too; even if you spread the cables out to make a more uniform field near the Earth's surface, field strength near each wire would be much greater than the breakdown point of most superconductors.
We'd probably never bother doing this, but it's a fun thought experiment
Re:..about time (Score:3, Interesting)
i've heard it stated that the black plague that
swept Europe and eliminated a sizable portion
of the population would be invisible in the
fossil record. So...perhaps during the shifts
things significantly sucked at the level of the
individual, but not enough to make a fossil
impact. If I had to bet though I'd go with the
no impact outcome.
20 Ways the World Could End (Score:5, Interesting)
This kinda freaks me out though..
Re:Down under... not any more! (Score:3, Interesting)
Some indian guy slightly north of Quito, Ecuador has what must be a lucrative business demonstrating this and a couple other things including his shrunken head collection (not sure if the heads are part of the standard tour, or were simply shown to me because I was so persistent about the water thing.. Others who had been there had not gotten it).
Re:Climatic disturbance (Score:5, Interesting)
And if the magnetic field of the Sun does indeed flip every 11 years as I saw in another post, that could be the cause. My astronomy teacher thinks that the polarity of the planets' magnetic fields is directly influenced by the Sun. Maybe the field on the Earth is directly affected by the flip on the Sun, such that the field gets weaker and weaker until it finally flips itself, then gets stronger to its peak, and finally repeats the process in the other direction.
bah! (Score:5, Interesting)
Apparently this article is a flare, to get the public thinking about magnetic field reversal, to hype the upcoming disaster-movie The Core. Expect this story to appear on CNN soon.
*newsflash* world to end 31 December! (Score:3, Interesting)
That said, it is true that the next cycle was supposed to be different from the old one, but that's hardly unusual or predictive. Look at our own culture's fascination with "in the year 2000" and "in the 21st Century," or even the selection of the year 1984 in a book written in 1948. It's close enough to be scary, but far away enough that it isn't overwheming.
the article is a hollywood advertisement! (Score:5, Interesting)
from the article:
Paramount's latest sci-fi thriller, The Core - directed by Englishman Jon Amiel, and starring Hilary Swank and Aaron Eckhart - depicts a world beset by just such a polar reversal, with radiation sweeping the planet.
wtf??
Re:Get real! (Score:3, Interesting)
It does not matter that the information itself is carried on light inside of fibers of glass. The signals inside the fiber can only travel ~100Km at the most before they need to be boosted again by an amplifier. This is done by doping a small section of the fiber with Erbium atoms and esentially making it lase(stimulated emission) by irradiating it with intense light from semiconductor lasers. There are common CONDUCTIVE cables cladding the main fiber line in a fiber optic cable that supply the amplifiers that are spread out all along the line with power to run. What happenes when huge lengths of conductive cable are immersed in a (potentially quickly) changing magnetic field? Thats right, gigantic currents are set up in the cable and can destroy [spaceweather.gc.ca] any sensitive devices connected to it. Thereby rendering the fiber dark.
Re:does that word mean what you think it means? (Score:5, Interesting)
Something that we could conceivably do within 50 years if we decided we really wanted to (along the lines of the Manhattan Project).
As opposed to, say, building a Dyson Sphere or some other project that requires either vastly more resources than are available, or materials that we have no idea to produce.
Re:Imposing our own field. (Score:3, Interesting)
*pulls out calculator* About four trillion metric tonnes, give or take a factor of four or so. If you're using aluminum, divide by about a factor of two (it's a third the density, but slightly more resistive).
and if you did, how does that compare to the amount of copper mined in the world every year? or even the entire amount of available copper in the world?
The amount available is obscenely large - you'd just have to strip-mine the faces of all continents to get at it.
Annual production of copper is around 16 Mt. Annual production of aluminum, which is probably more abundant given that the crust is aluminosilicates, is 26 Mt.
If we needed to build the cable badly enough to invest the effort, we'd vastly increase production (probably of aluminum, again because it's common). Assuming that we have enough bauxite strip mines and smelters to make power the limiting production factor, we'd produce about 0.1 Mt per second using the amount of power we'd devote to powering up the loop. It would take us about 5-10 years to produce the required quantity, not counting the time required to build smelters next to all of the power plants, railways for transport, and so forth (though some of the transport work has already been done, at coal-fuelled plants, at least).
It's not something that's _likely_ to be done, but it's _possible_ to do with the world's current industrial capability. Which is what makes it a fun thought-experiment.
oh, and by the way, given the amount of force that woukd be required to cut or break a hundred meter copper cable in the first place, i dont think the 10-gigaton or so discharge that results would be all that much more destructive.
It would, by about a factor of at least a hundred million.
How much dynamite does it take to turn a city block full of office buildings into a hundred-metre crater? That's about the level of force involved (maybe add a factor of 100 for the added weight and strength).
Let's be realistic (Score:5, Interesting)
Time now for some math.
Suppose a swallow is born 500 years from now. It's life span is what, 2-3 years? At the beginning of its life, the earth's magnetic strength is 0.5 as strong as it is today (500 years left/1000). By the end of the swallow's life it is 0.497 as strong (497 years left/1000), for a 0.6% change in magnetic field strength during the course of it's entire life. Less than one percent! Yeah, I think a swallow can deal with that.
If you are born with something (sound, energy, happiness, whatever) that is weaker than it was 1000 years ago, you do not even notice. It's that way all your life, and you cope with it. You never even consider it.
Re:nope (Score:2, Interesting)
If you're saying that mutations would be detrimental, and would result in a dead populace, perhaps evolution is a fraud.
God only knows...
Re:Get real! (Score:4, Interesting)
When you die, this world ends. Get real.
Denying your own immanent death is a far less
survivable delusion than the paranoia with which
you smear your rhetorical opponents.
Now in fact people live in the arctic where
the field lines converge, so the notion that
a collapse of the magnetic field would not
be survivable is prima facie absurd, but that
doesn't mean that *you* won't get killed by a
cyclone that results from ionospheric overheating.
Read all about it (Score:1, Interesting)
Re:Wouldn't surprise me to find this is so (Score:3, Interesting)
There is no real benefit to which way the poles point, the only thing it would do would mean that everyone had to buy or reconfigure their compasses...hmm maybe I've stumbled on to something. Who'd have suspected the quiet compass industry of something so evil
Second comment:
With regards to the frequency of the Earth, the Earth as a whole will have no resonant frequency because it is made up of different sections all of inconsistant phyiscal materials. For a whole object to have a single resonant frequency it must be the same material throughout. You could possibly get a resonant frequency that would shatter parts of the Earth's crust but the impact would be limited through the existance of unconformities, folding and the huge varieties of rocks that make up the crust.
So the comment you should have made is that every substance has a specific resonant frequency.
Re:nope (Score:3, Interesting)
That makes extinction more likely, not less. A modern society cannot revert to a pre-industrial state without 90% or more of its population dying in the process... subsistence farming simply can't support a population that grew on mechanized industrial farming. Not only that but most of the people won't have farming skills or tools, and there will be a sizeable minority who decide to just take by force rather than farm, which has a net result of reducing the chances of survival for everyone. Modern medicine and hygiene also means that our immune systems will have lost some of its capability.
If there is a cataclysm, any human survivors will probably be the natives of the Brazilian rainforests, if there are any left by then. How ironic that they can't survive the encroachment of modern civilization but could survive something that a modern civilization couldn't.
There were people executed - but for theft (Score:3, Interesting)
Less than that and you were transported.
The courthouse is a museum now.
Admittedly the law wasn't created to specifically deal with the poor but their lives were held in contempt. TBH if you survived the journey and lived out your sentence you probably ended up better off than back in Nottingham but still, not everyone did.
Whatever you want to call it, it was akin to genocide / slavery and it's a great injustice to those unfortunates and their antipodean descendents to be branded as criminals rather than victims.