Magnetic myths

by Donald Prothero via Skepticblog
Dec 26, 2012

All throughout the long buildup up to last week’s latest failed prediction of an global apocalypse, you would hear people claiming that the earth-shattering catastrophe of Dec. 21 would include “pole shifts” or “changes in the earth’s magnetic field” and all sorts of other sciencey phrases, proclaimed by people with absolutely no idea what they were talking about. The idea of “magnetism” is one of the most popular memes in the lexicon of pseudoscientists and New Agers, since magnets operate “mysteriously” and exert a force at a distance. From the days of Franz Mesmer claiming he had “magnetism” over people, to the trite phrase “animal magnetism,” the concept of magnetism has always been mysterious and misunderstood. Hence the big market for sticking magnets on various parts of your body to “cure” you. All they do is waste money, and possibly demagnetize the magnetic strip on your credit cards. The idea that somehow the earth’s magnetic field will shift abruptly or that the earth’s core will stop rotating (as in the idiotic Hilary Swank movie “The Core”) or even more wildly, that the earth’s rotational pole will change, are all common ideas out there in Wacko-Land.

Among the crazy ideas out there is that somehow the magnetic poles will shift and destroy all electrical devices (this web site), thus destroying civilization. Or this site, which claims that pole shifts will cause earthquakes and hurricanes, and NASA is covering up what’s happening. Or this bizarre post, which freely uses the words “gruesome” and “horror”. Or this site, which cherry-picks items from actual science posts and then completely misinterprets what they mean.

This is just a small sampling of the pseudoscientific garbage all over the internet posted before Dec. 21. Most of us know enough about science and apocalyptic predictions to guess that they are not worth taking seriously, but very few people have bothered to debunk this stuff. Unfortunately, we saw lots of sad consequences of people who did take the ridiculous apocalyptic predictions seriously, often with tragic results.

Among my other specialties, my professional training is in paleomagnetism, and I’ve conducted over 35 years of published research in the field, so I’m pretty familiar with what we do and don’t know about the earth’s magnetic field and how it behaves.

First, some science. The earth’s magnetic field has at least two components, the dipolar field (illustrated above), which makes up about 90% of the magnetism we normally feel, and a non-dipole field, which is normally hard to detect beneath it but makes up at least 10% of the earth’s field. The dipole field is not exactly lined up with the rotational axis of the earth (i.e., there is a small angle between magnetic north and true north), but over geologic spans of time, magnetic north wanders around the vicinity of the rotational pole; this movement known as secular variation. Studies have shown … MORE . . ..

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