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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."
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.
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.
I can pretty much guarantee that astrologers would have no idea what you're talking about :)
That's correct. According to their theory, moons like Europa should have a rather strong magnetosphere.
Europa is believed to have a warm, salty ocean under the ice crust. And yet, it shows only slight inducted magnetic field from Jupiter. Contrast that with Ganymede, the only moon with its own magnetosphere and a liquid iron core. Satellite photos dont show very much (or any) water on its surface.
Hmm.
Because the other theory hasn't been tested, and might be wrong.
The point is that the chances that each celestial body's magnetic field is due to a unique generator are... Well, let's say that that is not what we typical see in scientific history. Similar effects are generated by similar causes, especially at planetary scales.
(I see that I've been misled by the summary, as usual. Yes, I should RTFA. But the editors should fucking WTFS in a manner resembling responsible journalism. Could currents in the oceans modulate the magnetic field? Worth investigation, I think.)
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.
Um, this is /. so I'm not sure "right-hand rule" always means what you think it does here. :-) I'm sure a lively debate could ensue on "science geek" vs. "lonely geek".
It must have been something you assimilated. . . .
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.
Science has always reserved its greatest accolades for those who prove what came before to be wrong, and every scientist in the world knows the best way to become famous is to prove everyone else wrong. Nevertheless, pseudo-scientists always argue that scientists have some vested interest in preserving the current order (and thus dooming their careers into obscurity when they could have become famous Nobel prize winners). This argument has never made any sense, but that doesn't stop them from making it. So, one more example won't make any difference to them -- people who advocate a bad argument that runs counter to evidence are not dissuaded by more evidence.
"Convictions are more dangerous enemies of truth than lies."
Of course water responds to solar radiation - that's how we get clouds! :-)
A cheerful little bird is sitting here singing.
Hundreds if not thousands of direction changes are documented, back into the Triassic at least and possibly into the Late Palaeozoic. There are sufficient that, in more recent times (Cretaceous onwards) the reversal record has been used as a tool for correlation. (Such work may go back further into the geological record ; I've certainly seen it used in Cretaceous mudrock sequences as a petrophysical indicator that can be measured faster and with less skilful operators than other techniques like palynology.)
For certain values of "overdue" ; the distribution of durations between reversal events seems to be essentially random, and since we're over the average duration between reversals, then one could meaningfully "expect" a reversal sooner rather than later. But once you start looking at the statistics, you have to accept that, if the model is accurate, then the probability of a reversal in the next thousand years (say), is the same as the probability of a reversal in the first thousand years after the last reversal. It's the same logic as tossing coins - if you get ten heads in a row, the probability of your next toss being a head is still 1/2, even if the probability of getting 11 heads in a row is 1/2048. Random variables - love 'em or hate 'em, but you can't predict 'em.
That said, outside the statistical description of the record, the physical models suggest that some events seen at the moment (decreasing field strength ; regional anomalies) may be precursors to a reversal.
Has someone been claiming global warming to be related to magnetic field strength? Whooo, can I get a smoke of that? Sounds like good gear.
Birds are not dinosaur descendants;birds are dinosaurs, for all useful meanings of "birds", "are" and "dinosaurs"