Tag Archives: Earth’s magnetic field

Why does the North Pole move?

From the “Almost Too Stupid to Post” file . . .

Almost too stupid_wide_250pxThis post is for all those doomsayers building backyard bunkers in preparation for the day the world comes to an end because of the north and south poles shifting.

Yes, some people fear the day the north and south poles shift their positions or even reverse positions. They believe such a shift in the Earth’s magnetic field will result in earthquakes, tsunamis, global climatic change and eventually the destruction of our planet.

(As a side note: Are there ANY conspiracy theories out there that DON’T end with everybody being annihilated or the planet being destroyed? Just asking. I’m beginning to suspect there is a conspiracy to NOT have any conspiracies with a happy ending. But i digress . . . :))

The following article explains the regularity of pole shifting. Apparently, the poles have only been shifting every hour of everyday for a gazillion years. The north and south poles have even swapped positions 400 times in the last 330,000,000 years.

So open your bunker doors dear doomsdayers, it’s safe to crawl out – – – and don’t forget your compasses.

Mason I. Bilderberg (MIB)

by via HowStuffWorks

Click for larger view.
In the last 150 years, the pole has wandered a total of about 685 miles (1102 kilometers).
Image courtesy Kenai National Wildlife

The Earth has several poles, not just two. It has geographic north and south poles, which are the points that mark the Earth’s axis of rotation. It also has magnetic north and south poles, based on the planet’s magnetic field. When you use a compass, it points to the magnetic north pole, not the geographic North Pole.

The Earth’s magnetic poles move. The magnetic North Pole moves in loops of up to 50 miles (80 km) per day. But its actual location, an average of all these loops, is also moving at around 25 miles a year [ref]. In the last 150 years, the pole has wandered a total of about 685 miles (1102 kilometers). The magnetic South Pole moves in a similar fashion.

The poles can also switch places. Scientists can study when this has happened by examining rocks on the ocean floor that retain traces of the field, similar to a recording on a magnetic tape. The last time the poles switched was 780,000 years ago, and it’s happened about 400 times in 330 million years. Each reversal takes a thousand years or so to complete, and it takes longer for the shift to take effect at the equator than at the poles. The field has weakened about 10% in the last 150 years. Some scientists think this is a sign of a flip in progress.

The Earth’s physical structure is behind all this magnetic shifting. The planet’s inner core is made of solid iron. Surrounding the inner core is a molten outer core. The next layer out, the mantle, is solid but malleable, like plastic. Finally, the layer we see every day is called the crust.

The Earth itself spins on its axis. The inner core spins as well, and it spins at a different rate than the outer core. This creates a dynamo effect, or convections and currents within the core. This is what creates the Earth’s magnetic field — it’s like a giant electromagnet.

MORE . . .

Magnetic myths

by Donald Prothero via Skepticblog
Dec 26, 2012

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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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