2012: Magnetic pole reversal happens all the (geologic) time

Nov 30, 2011 By Patrick Lynch
Schematic illustration of Earth's magnetic field. Credit/Copyright: Peter Reid

Scientists understand that Earth's magnetic field has flipped its polarity many times over the millennia. In other words, if you were alive about 800,000 years ago, and facing what we call north with a magnetic compass in your hand, the needle would point to 'south.' This is because a magnetic compass is calibrated based on Earth's poles. The N-S markings of a compass would be 180 degrees wrong if the polarity of today's magnetic field were reversed. Many doomsday theorists have tried to take this natural geological occurrence and suggest it could lead to Earth's destruction. But would there be any dramatic effects? The answer, from the geologic and fossil records we have from hundreds of past magnetic polarity reversals, seems to be 'no.'

Reversals are the rule, not the exception. Earth has settled in the last 20 million years into a pattern of a pole reversal about every 200,000 to 300,000 years, although it has been more than twice that long since the last reversal. A reversal happens over hundreds or thousands of years, and it is not exactly a clean back flip. fields morph and push and pull at one another, with multiple poles emerging at odd latitudes throughout the process. Scientists estimate reversals have happened at least hundreds of times over the past three billion years. And while reversals have happened more frequently in "recent" years, when dinosaurs walked Earth a reversal was more likely to happen only about every one million years.

Sediment cores taken from floors can tell scientists about shifts, providing a direct link between activity and the fossil record. The Earth's magnetic field determines the magnetization of lava as it is laid down on the on either side of the Mid-Atlantic Rift where the North American and European are spreading apart. As the lava solidifies, it creates a record of the orientation of past magnetic fields much like a tape recorder records sound. The last time that Earth's poles flipped in a major reversal was about 780,000 years ago, in what scientists call the Brunhes-Matuyama reversal. The shows no drastic changes in plant or animal life. Deep ocean from this period also indicate no changes in glacial activity, based on the amount of oxygen isotopes in the cores. This is also proof that a polarity reversal would not affect the rotation axis of Earth, as the planet's rotation axis tilt has a significant effect on climate and glaciation and any change would be evident in the glacial record.

A schematic diagram of Earth's interior and the movement of magnetic north from 1900 to 1996. The outer core is the source of the geomagnetic field. Graphic Credit: Dixon Rohr

Earth's polarity is not a constant. Unlike a classic bar magnet, or the decorative magnets on your refrigerator, the matter governing Earth's magnetic field moves around. Geophysicists are pretty sure that the reason Earth has a magnetic field is because its solid iron core is surrounded by a fluid ocean of hot, liquid metal. This process can also be modeled with supercomputers. Ours is, without hyperbole, a dynamic planet. The flow of liquid iron in Earth's core creates electric currents, which in turn create the magnetic field. So while parts of Earth's outer core are too deep for scientists to measure directly, we can infer movement in the core by observing changes in the magnetic field. The magnetic north pole has been creeping northward – by more than 600 miles (1,100 km) – since the early 19th century, when explorers first located it precisely. It is moving faster now, actually, as scientists estimate the pole is migrating northward about 40 miles per year, as opposed to about 10 miles per year in the early 20th century.

Another hypothesis about a geomagnetic flip plays up fears about incoming solar activity. This suggestion mistakenly assumes that a pole reversal would momentarily leave Earth without the magnetic field that protects us from solar flares and coronal mass ejections from the sun. But, while Earth's magnetic field can indeed weaken and strengthen over time, there is no indication that it has ever disappeared completely. A weaker field would certainly lead to a small increase in solar radiation on Earth – as well as a beautiful display of aurora at lower latitudes -- but nothing deadly. Moreover, even with a weakened magnetic field, Earth's thick atmosphere also offers protection against the sun's incoming particles.

The science shows that magnetic pole reversal is – in terms of geologic time scales – a common occurrence that happens gradually over millennia. While the conditions that cause polarity reversals are not entirely predictable – the north pole's movement could subtly change direction, for instance – there is nothing in the millions of years of geologic record to suggest that any of the 2012 doomsday scenarios connected to a pole reversal should be taken seriously. A reversal might, however, be good business for manufacturers.

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encoded
3.9 / 5 (7) Nov 30, 2011
you have got to be kidding
kevinrtrs
1.3 / 5 (16) Dec 01, 2011
Geophysicists are pretty sure that the reason Earth has a magnetic field is because its solid iron core is surrounded by a fluid ocean of hot, liquid metal

One needs to read this carefully and take the insinuation with a rock of salt.
Even though the Geophysss would like to create the impression of absolute certainty, it's not so. The computer simulations are so complex that no conclusive statements can be made.
The one reason for the complexity is that the model needs to show that the field is self-sustaining and capable of surviving for billions of years, contrary to the hard reality that actual, physical verifiable measurements show that the field strength is rapidly decreasing.
The far simpler and more realistic explanation for the existence and state of the field is that it had a once off kick-start and is now in natural exponential decay. The actual measurements fit this model far better.
However, philosophic considerations dictate matters. So there it is.
fmfbrestel
5 / 5 (7) Dec 01, 2011
Earth has settled in the last 20 million years into a pattern of a pole reversal about every 200,000 to 300,000 years, although it has been more than twice that long since the last reversal.

...

And while reversals have happened more frequently in "recent" years, when dinosaurs walked Earth a reversal was more likely to happen only about every one million years.


how do those statements (unless your contention is that they are lies) fit anywhere close to:

The far simpler and more realistic explanation for the existence and state of the field is that it had a once off kick-start and is now in natural exponential decay. The actual measurements fit this model far better.


??

They were slow, then they sped up, and now they are slowing down again.

If we are measuring deception, I think your statements fit the model of a lie far better.
kevinrtrs
1.3 / 5 (16) Dec 01, 2011
A reversal happens over hundreds or thousands of years

I don't know where the authors got this particular statement from but some volcanic activities show that reversals occur[ed] over a very short space of time, weeks or months at the most.
One problem with long slow reversals is the question it raises over just what happens if the field reverses and diminishes for such a long time? Just how weak does it actually get and what are the effects? Making statements that it doesn't get "THAT" weak begs the question as to whether anyone has observed such a change and recorded its characteristics so that we can know it doesn't get "that" weak". The authors are simply guessing and hoping they can get away with no supporting evidence.
kevinrtrs
1.3 / 5 (15) Dec 01, 2011
They were slow, then they sped up, and now they are slowing down again.

You of course have evidence that this is the case, contrary to what we can actually observe and what people have observed through measurements over the past 150 years?
Do you have measurements taken 150 million years ago? You don't. All measurements referring to that kind of age are inferred and attributed according to how the age of the rocks are determined - based on controversial assumptions.
Actual records of measurements beat those anytime.
Callippo
1.3 / 5 (12) Dec 01, 2011
IMO the geomagnetic poles are switched with distribution of dark matter mass inside of solar system. When the solar system is going to pass through dark matter at the galactic plane, then the center of mass of Earth is shifted and the liquid mantle circulation is affected with it. The antineutrinos tend to accelerate the decay of radioactive elements inside of Earth mantle and the they're increase the speed of its circulation. The solar activity IMO cannot influence of Earth mantle motion directly, but they're correlated mutually in time, because the neutrino distribution inside of solar system affects the circulation of solar plasma as well. When the center of mass is shifted bellow surface of Sun, it could stop the circulation of solar plasma, it's overheating which leads to the sunspots, protuberance and solar flare formation. The distribution of planets inside of solar system can play its role too, because it affects the location of center of mass heavily.
Callippo
1.4 / 5 (12) Dec 01, 2011
The people should realize, how the neutrinos are working. They're so tiny and they don't interact with light, so they're virtually unobservable. But they're many of them and they surround every massive object like invisible cloud of irregular structure, which is in thermal equillibrium with CMB radiation. The blow of neutrinos from center of galaxy would blow out this thin neutrino atmosphere from all planets inside of solar system, thus affecting the distribution of mass inside of solar system significantly.

In addition, there are two types of neutrinos, the Sun is generating normal neutrinos, which slow down the radioactive decay, but the neutrinos from the center of galaxy are antineutrinos and they do accelerate it. The inner heat of planets is powered with radioactive decay, so that such replacement of neutrinos inside of solar system can have wide impact to the thermal regime of all planets and Sun at the same moment.

It's just a hypothesis, but it's relatively well supported.
Eoprime
5 / 5 (3) Dec 01, 2011
It's just a hypothesis, but it's relatively well supported.


Source... (a credible one)

But i know your 'sources' so dont bother me with waterripple nonsense. (you shouldn't inhale your ä/ether but drop it)
Fionn_MacTool
2.5 / 5 (8) Dec 01, 2011
I remember when I was younger I travelled to Angkor Wat and learned about the "Rainbow Bridge" which was a link between this world and the heavens. As a European with a Scandinavian parent I was also aware of Norse mythology and the "Rainbow Bridge" which connected this world with Asgard. It always made sense to me that in Northern Europe they would have seen the northern lights and thought they were supernatural. Perhaps the same experiences have been recorded as far South as Cambodia who then tried to explain them as best they could?

I would love to know what effect changes in the strength of the magnetic field has on humans magnetoreception (and how we even experience those sensations). I always theorised that humans do sense magnetic fields and even the construction of "sacred/holy" sites are associated with this perception. I have no direct evidence though to back that up.
Fionn_MacTool
1.8 / 5 (5) Dec 01, 2011
I think if people could sooner see the relationship between the sun and solar activity, the earth and its magnetic field, and there combined effect on agriculture, a lot of what our ancestors built would probably make more sense.
Jeddy_Mctedder
2.6 / 5 (5) Dec 01, 2011
the suns magnetic flpis every 22 years or so. and nothing huge is obserbed---- so why would this be so surprising if the earths magnetic field flipping was not coincident with dramatic changes?
fmfbrestel
5 / 5 (4) Dec 01, 2011
Actual records of measurements beat those anytime.


so direct measurements over the last 150 years are more meaningful than indirect measurements over the last few billion years? Do you even have a grasp on geologic time scales? Thats like saying you can get a reading on today's average global temperate by taking 5 measurements from your front porch over a 5 second time period.

Of course if you really believe that the earth is only a few thousand years old, and scientists are nothing more than agents of the devil dividing humanity from god, then ya you probably think this type of research is a bunch of bull.
exter
not rated yet Dec 04, 2011
"A schematic diagram of Earth's interior and the movement of magnetic north from 1900 to 1996. The outer core is the source of the geomagnetic field. Graphic Credit: Dixon Rohr" Yet the diagram shows 1990 to 1996?
jsa09
not rated yet Dec 04, 2011
good point exter. It is hard to get good help these days.

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