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Ocean Currents Proposed As Cause of Magnetic Field
pjt33 notes a recently published paper proposing that ocean currents could account for Earth's magnetic field. The wrteup appears on the Institute of Physics site; the IOP is co-owner, with the German Physical Society, of the open-access journal in which the paper appears. This reader adds, "The currently predominant theory is that the cause of Earth's magnetic field is molten iron flowing in the outer core. There is at present no direct evidence for either theory." "Professor Gregory Ryskin from the School of Engineering and Applied Science at Northwestern University in Illinois, US, has defied the long-standing convention by applying equations from magnetohydrodynamics to our oceans' salt water (which conducts electricity) and found that the long-term changes (the secular variation) in the Earth's main magnetic field are possibly induced by our oceans' circulation."
There is enough junk floating on the oceans that the currents could be ferrous.
So basically we know that global warming has taken over our ocean's currents when our compasses start pointing to the south...
Aren't there planets that do have magnetic fields, but don't have oceans? And aren't there moons that are the opposite case?
At the bottom of the
Yeah, that makes a whole hell of a lot of sense. Why not invent some brand new, goofy theory that applies only to the Earth and not to any of the other celestial bodies that we know have magnetic fields which DON'T have oceans? Has somebody never heard of Occam's Razor? Instead of one theory which works to explain all magnetic fields on all celestial bodies why not invent something stupid for no good reason?
Fascinating! If true, I wonder how it could effect theories on terraforming. If we got enough open and moving water on Mars could it then develop the field needed to block solar radiation and trap an atmosphere?
The Slashdot summary is totally wrong.
From the abstract of the paper: "I propose a different mechanism of secular variation: ocean water [...] as it flows through the Earth's main field may [...] manifest itself globally as secular variation."
Meaning: There is a major magnetic field that comes from the molten core. However, certain variations that are as yet unexplained may not result from core phenomena, but from the ocean currents.
I find this much more believable than the swill in the slashdot summary.
What was it before?
A coffee coaster.
The magnetic field is believed to prevent solar wind from eroding water and oxygen. If ocean water creates a magnetic field that prevents water from eroding .... that's a serious chicken/egg problem. FWIW, Mars used to have water and may have at one point had a stronger magnetic field than the Earth. It currently has a weak magnetic field and negligible water. Mars doesn't have a large moon to create tides, either.
Do you even lift?
These aren't the 'roids you're looking for.
Comment removed based on user account deletion
The sun doesn't appear to have much in the way of flowing iron at its core either. Does that mean that it can't have a magnetic field?
Essentially the theory stands at : flows of conductive fluid ( salt water, iron, plasma ) can generate magnetic fields. We have no evidence that there is flowing iron in the earth's core, but we have rather a lot of flowing salt water. Hmmm...
The fact that no one understands you doesn't mean you're an artist.
Just last night there was an interesting show on television that focused on the subject of magnetic fields associated with planets.
There was an experiment covered in the show that was essentially a large, hollow orb filled with liquid sodium (a substitute for the iron at Earth's outer core. It is impossible to reproduce the pressure and heat of our Earth's guts in such a small scale experiment) which was then spun at a comparatively equal rate to that of Earth. The orb began producing strong magnetic fields.
I somehow doubt that if the same experiment were to be reproduced solely with a thin layer of salt water on the surface (and no sodium inside) that it would produce such strong magnetic fields. That being said, while the thought of Earth's magnetic field being produced solely by the water on the surface is interesting, personally I think it is more then likely a combination of the two factors rather then one alone that produces our protective magnetic field.
In addition, I wonder if the flux in ocean water levels, historically speaking, coincides with the strength and direction of past magnetic fields as recorded in ancient lava flows. If so, this would seem to back up the theory proposed in the article.
The paper does not say that ocean currents cause the magnetic field. It hypothesizes that ocean currents cause secular variations in the magnetic field.
Warning: this article may contain humor, sarcasm, parody, and perhaps even irony. Read at your own risk.
Note how this dishes the favorite argument of pseudoscientists, who always (always, always) claim that the scientific "establishment" refuses to hear evidence that conflicts with accepted wisdom. Rather - to the extent that such an establishment can be said to actually exist - science will entertain any sort of extreme argument, as long as it is cogently - and entertainingly - presented. To overturn competing theories extreme arguments ultimately demand extreme evidence, however.
Ocean currents? Here's an even better idea : winds! I know it's true because when I throw a fridge magnet in the wind it goes in the same direction. So next time you want to know in what direction the wind is going, just look at a magnetic compass!
You just got troll'd!
To be certain, there are NO 'theories' for Earth's magnetism, only a variety of HYPOTHESIS'S.
Once again the term theory is being misused for HYPOTHESIS. It is a great disservice to science and scientists to not understand the definition and implications for both terms.
A worker whose research achieves the level of Theory is among the 'Nobel class' of scientists. Therefore the term should be used properly and with some reverence.
So before we go any further, would someone venture to post the scientific definitions and usage for these two terms, hypothesis and Theory.
Thanx
the general argument here is that other planets lacking oceans also have magnetic fields-- so that ain't right..
so I'm thinking, what do all solar bodies have in common that could be another means to that end
solar wind? the flow of all the radiation from the sun, wrapping around the planet, and blowing on? happens to all objects in the system??
every day http://en.wikipedia.org/wiki/Special:Random
Too soon?
Funny words from someone who used rather massive ad hominem by trying to label people disagreeing with him as zealots.
Consensus is used as an argument because not all of us can be climate scientists. There is large consensus among them that global warming is happening and caused by men. Not all agree to that. Name any theory and you have people who disagree with it. Hell, there is even a flat earth society. But big majority of the expert who know about the subject and have studied it their whole lives believe so.
Most of the people who argue about it in the internet aren't climate scientists. They've read a few stories which have quoted some climate scientists who disagree with the mainstream and then begin arguing. To them I can always answer "Hey, I am not an expert in the field. And honestly, most likely you aren't either. When your arguments are good enough that they manage to sway opinions of the expert, then you can come back to me. Otherwise I have all the reason to assume that there is some flaw in them."
All of us who aren't experts in every field of science have to do that about some subjects. Trust the scientific method and through that, the experts who employ it.
While I have no expertise in this area ... Are ocean current patterns really as static as the Earth's magnetic field?
Yes. Neither are static, both change continuously, but both are relatively slowly changing phenomena.
I'd think that there would be more fluctuations/variations in the Earth's magnetic field if it depended on the waterbodies.
On geological timescales, it would change dramatically. Which, we know, it does.
Wouldn't this also require compasses / magentic fields being disrupted when there are earthquakes/tsunamis or major storms?
No, since large-scale ocean currents are not noticeably affected by these things.
"Convictions are more dangerous enemies of truth than lies."
Yes exactly water ice in comets. Do you know what a comet's tail is made out of? Water evaporated and removed from the comet by solar radiation.
Imagine a puddle waking up one morning and thinking, 'This is an interesting world I find myself in, an interesting hole I find myself in, fits me rather neatly, doesn't it? In fact it fits me staggeringly well, must have been made to have me in it!' This is such a powerful idea that as the sun rises in the sky and the air heats up and as, gradually, the puddle gets smaller and smaller, it's still frantically hanging on to the notion that everything's going to be alright, because this world was meant to have him in it, was built to have him in it; so the moment he disappears catches him rather by surprise. - D. Adams.
And did you exchange a walk on part in the war for a lead role in a cage? - Pink Floyd.
Of course water responds to solar radiation - that's how we get clouds! :-)
A cheerful little bird is sitting here singing.
He also says:
I think Mr. Ryskin is well aware that he hasn't presented enough evidence to refute the prior hypothesis. He's only pointing out that secular variation has been considered important evidence supporting the dynamo theory. An alternate explanation for the variation wouldn't necessarily falsify the dynamo theory, but it could take away supporting evidence.
But he is correct that this should stimulate further research. His paper mentions enough analytical simplifications and limitations in the source data to suggest thesis topics for an army of grad students. I'm sure there will also be much thought about how the dynamo hypothesis might be independently confirmed.
Mars also has much lower gravity; basically what determines loss of volatiles is if the radiation impacting on the top of the atmosphere can give the molecules escape velocity. The actual mechanism is a bit more complicated than that, but is ultimately bound by conservation of energy.
Mars also didn't lose all its atmosphere to space - some froze as dry ice.
If we can put a man on the moon, why can't we shoot people for Apollo-related non-sequiturs?
In fact, Earth right now is leaking atmosphere faster than Mars is, pound for pound.
Considering how thin Mars' atmosphere is, that's not at all surprising.
-jcr
The only title of honor that a tyrant can grant is "Enemy of the State."
We have proven the existence of a molten outer core inside the Earth, and the proof doesn't depend on the magnetic field, but rather, seismology. Sound and vibration can travel in any substance as a pressure wave - material compressing and decompressing (P-waves). In solids, vibration can also be orthogonal to the direction of propagation (S-waves). Think of vibration in a string, or in a tuning fork. It is known empirically that S-waves travel through the Earth only to certain depth. Because they can't propagate deeper than that, the material must be unsuitable for S-waves, which means liquid.
Now, if there's a liquid, a gravitational field, and a temperature difference, convective flow must be present too. In addition, this liquid outer core is circulating around the Earth's axis. So the "geodynamo" still seems like the best explanation to me (I recommend Fowler's The Solid Earth if anyone's actually interested in the science and reasoning behind all this).
the long-term changes (the secular variation) in the Earth's main magnetic field are possibly induced by our oceans' circulation.
This here is what the article actually states. I'm not surprised that oceanic currents can correlate with the details of the magnetic field, as the field is known to be the result of several phenomena. Actually this finding can turn out to be supporting the geodynamo idea, as one problem with the geodynamo is why the magnetic field is such a mess ;). Maybe core currents generate most of the magnetic field and oceans add variation to it.
We're overdue now by several thousand years.
Not to sound ignorant, but why is it that we're overdue for:
We're overdue for everything, such that, I'm overdue for some coffee.
I know it's Monday morning: don't worry about being late.