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Earth's Magnetic Pole Reversals / 'Flips'

Re: Picture this.

Bill said:
Now! on the longest day(21 june) over 20 years ago the Sun would set(ACCORDING TO MY HORIZON)just LEFT of the CHIMNEY opposite me.
Now!in 2004 the Sun set RIGHT OF THE SAME CHIMNEY and quit a way to!!!!!.
I have been observing this for years now every 21st June and it is a pitty i have not gotten all of this on film.
What do you make of that???
Bill.

I don't think the Earths axis has shifted dramaticly over the past twenty years, but there are probably small effects caused by leap years that can mean that the sun is in different positions on the 21st of June.

There is quite a good site that explains changes in the Earths tilt here: http://www.doc.ic.ac.uk/~kpt/terraquest/va/ecology/ecology.html#B
It is now believed that a cycle of three main irregularities, in the Earth's orbit are the main factors initiating an ice age. These are as follows:


The first irregularity is the tilt of the earth's axis from 22ƒ to 25ƒ which occurs in a cycle that repeats itself every 41,000 years. (A change in the earth's tilt changes the amount of heat from the sun that reaches the polar regions.)

The second irregularity is the orbital procession which completes its cycle every 21,000 years. This determines the season at which the earth is closest to the sun during its orbit. Currently the earth is further from the sun during the northern hemisphere's summer than in the winter.

The third cycle, with a period of 100,00 years, alters the shape of the earth's orbit, and its eccentricity amplifies or minimises the effect of the procession. This was first put forward in the 1870's by a Scottish amateur scientist, James Croll, and verified in the 1920's by a Serbian mathematician, Milutin Milankovitch. He showed that these variations were the basis for the significantly cooler summers every 21,000 and 41,000 years. These could help cause an ice age by beginning the build up of ice at the poles. The additional time it took for the icesheets to grow to their maximum sustainable size has been suggested as reason for the ice ages occurring every 100,000 years.
 
Chicken littles?

Earth's Magnetic Field Is Fading

John Roach
for National Geographic News
September 9, 2004

Earth's magnetic field is fading. Today it is about 10 percent weaker than it was when German mathematician Carl Friedrich Gauss started keeping tabs on it in 1845, scientists say.

If the trend continues, the field may collapse altogether and then reverse. Compasses would point south instead of north.

Not surprisingly, Hollywood has already seized on this new twist in the natural-disaster genre. Last year Tinseltown released The Core, a film in which the collapse of Earth's magnetic field leads to massive electrical storms, blasts of solar radiation, and birds incapable of navigation.

Entertainment value aside, the portrayal wasn't accurate, according to scientists who say the phenomenon of Earth's fading magnetic field is no cause to worry.

"The field has reversed many times in the past, and life didn't stop," said Gary Glatzmaier, an earth scientist and magnetic field expert at the University of California, Santa Cruz.

Glatzmaier is keeping an eye on our planet's weakening magnetic field as he tries to learn more about how Earth's geodynamo works. The geodynamo is the mechanism that creates our planet's magnetic field, maintains it, and causes it to reverse.

Magnetic Shield

Earth's geodynamo creates a magnetic field that shields most of the habited parts of our planet from charged particles that come mostly from the sun. The field deflects the speeding particles toward Earth's Poles.

Without our planet's magnetic field, Earth would be subjected to more cosmic radiation. The increase could knock out power grids, scramble the communications systems on spacecraft, temporarily widen atmospheric ozone holes, and generate more aurora activity.

A number of Earth's creatures, including some birds, turtles, and bees, rely on Earth's magnetic field to navigate. The field is in constant flux, scientists say. But even without it, life on Earth will continue, researchers say.

"There are small fluctuations, which lead to nothing, and large ones, which we know from the geologic record are associated with reversals," said Peter Olson, a geophysicist at Johns Hopkins University in Baltimore, Maryland.

When molten lava erupts onto the Earth's crust and hardens, it preserves a snapshot of Earth's polarity, much in the way that iron filings on a piece of cardboard align themselves to the field of a magnet held beneath it.

According to Earth's geologic record, our planet's magnetic field flips, on average, about once every 200,000 years. The time between reversals varies widely, however. The last time Earth's magnetic field flipped was about 780,000 years ago.

"We hear the magnetic field today looks like it is decreasing and might reverse. What we don't hear is it is on a time scale of thousands of years," Glatzmaier said. "It's nothing we'll experience in our lifetime."

But several generations from now, humans just may witness a reversal. By then, Glatzmaier said, scientists will better understand the process and be prepared to cope with the effects.

Geodynamo

Scientists believe the magnetic field is generated deep inside the Earth where the heat of the planet's solid inner core churns a liquid outer core of iron and nickel.

The solid inner core is thought to be a mass of iron about the size of the moon that is heated to several thousand degrees Fahrenheit. Heat radiated by this inner core builds up at its boundary with Earth's liquid outer core, causing the fluid there to expand.

"When it expands it becomes a little less dense [and more] buoyant. So it starts to rise. That's convection," Glatzmaier said. "Hot fluid rises, then cools off and sinks again."

The convection generates an electric current and, as a result, a magnetic field.

Additional currents are created as Earth cools. Some of the molten iron solidifies onto the inner core, releasing lighter material in the process. The rotation of the Earth also generates forces that curve the flow of fluid as it rises, twisting the magnetic field.

All of these currents constantly replenish the magnetic field, a maintenance process that prevents it from decaying.

Typically each newly generated field lines up in the direction of the existing magnetic field. But every now and again, some force will cause the new field to line up in the opposite direction. This process can lead to a net weakening of Earth's magnetic field.

Over time a new field can continue to grow. This further weakens the original magnetic field. If the process continues, the two fields would eventually cancel each other out. Earth's magnetic field would collapse and then, maybe, flip.

"But more likely than not what will happen is the original [field] will get stronger again and overwhelm the instability," Glatzmaier said.

http://news.nationalgeographic.com/news/2004/09/0909_040909_earthmagfield.html
 
Why Does Earth's Magnetic Field Flip?

John Roach
for National Geographic News
September 27, 2004

Earth's magnetic field has flipped many times over the last billion years, according to the geologic record. But only in the past decade have scientists developed and evolved a computer model to demonstrate how these reversals occur.

"We can see reversals in the rocks, but they don't tell us how it happens," said Gary Glatzmaier, an earth scientist and magnetic field expert at the University of California, Santa Cruz.

Based on a set of physics equations that describe what scientists believe are the forces that create and maintain the magnetic field, Glatzmaier and colleague Paul Roberts at the University of California, Los Angeles, created a computer model to simulate the conditions in the Earth's interior.

The computer-generated magnetic field even reverses itself, allowing scientists to examine the process.

Computer Model

Scientists believe Earth's magnetic field is generated deep inside our planet. There, the heat of the Earth's solid inner core churns a liquid outer core composed of iron and nickel. The churning acts like convection, which generates electric currents and, as a result, a magnetic field.

This magnetic field shields most of the habited parts of our planet from charged particles that emanate from space, mainly from the sun. The field deflects the speeding particles toward Earth's Poles.

Our planet's magnetic field reverses about once every 200,000 years on average. However, the time between reversals is highly variable. The last time Earth's magnetic field flipped was 780,000 years ago, according to the geologic record of Earth's polarity.

The information is captured when molten lava erupts onto Earth's crust and hardens, much in the way that iron filings on a piece of cardboard align themselves to the field of a magnet held beneath it.

Most scientists believe our planet's magnetic field is sustained by what's known as the geodynamo. The term describes the theoretical phenomenon believed to generate and maintain Earth's magnetic field. However, there is no way to peer 4,000 miles (6,400 kilometers) into Earth's center to observe the process in action.

That inability spurred Glatzmaier and Roberts to develop their computer model in 1995. Since then, they have continued to refine and evolve the model using ever more sophisticated and faster computers.

The model is essentially a set of equations that describe the physics of the geodynamo. The equations are continually solved, each solution advancing the clock forward about a week. At its longest stretch, the model ran the equivalent of 500,000 years, Glatzmaier said.

By studying the model, the scientists discovered that, as the geodynamo generates new magnetic fields, the new fields usually line up in the direction of the existing magnetic field.

"But once in a while a disturbance will twist the magnetic field in a different direction and induce a little bit of a pole reversal," Glatzmaier said.

These bits of a pole reversal are referred to as instabilities. They constantly occur in the fluid flow of the core, tracking through it like little hurricanes, though at a much slower pace—about one degree of latitude per year.

Typically, instabilities are temporary. But on very rare occasions, conditions are favorable enough that the reversed polarity gets bigger and bigger as the original polarity decays. If this new polarity takes over the entire core, it causes a pole reversal.

"It's a very complicated, chaotic system, and it has a life of its own," Glatzmaier said.

Weak Spot

Peter Olson, a geophysicist at Johns Hopkins University in Baltimore, Maryland, said scientists can now pinpoint the core-mantle boundary where these instabilities in the magnetic field are happening.

One such disturbance Olson has been observing recently formed over the east-central Atlantic Ocean. Like a little hurricane, the anomaly swept toward the Caribbean and is moving up in the direction of North America.

"It's a new one, a little thing," Olson said. "Time will tell whether it develops into something significant. But it is here in the North Atlantic, moving towards the Pentagon. We can track it over the next couple of decades."

Instabilities such as this, Olson added, are causing Earth's magnetic field to weaken. Today the field is about 10 percent weaker than it was when German mathematician Carl Friedrich Gauss first began measuring it in 1845. Some scientists speculate the field is headed for a reversal.

http://news.nationalgeographic.com/news/2004/09/0927_040927_field_flip.html
 
Ian Niall Rankin has just published a book called 'Doomsday Just Ahead' which proclaims that the earth will tilt on its' axis in 30 years.

He has also just been interviewed on Johnnie Walkers' Radio 2 programme - to listen to the interview go here:

http://www.bbc.co.uk/radio2/shows/walker/biography.shtml

and click on 'Tue' in the purple Listen Again bar.

it's about 1 hour 25 minutes into the programme (it uses RealPlayer and you can skip ahead by 15 or 5 minutes at a time to find the right place)

Note: these 'listen again' programmes are overwritten every 7 days, so get it while it's, er, hot. :)
 
http://www.pureenergysystems.com/news/2005/02/27/6900064_Magnet_Pole_Shift/
Earth Magnetic Field Reversal
Possible energy ramifications of diminishing magnetic field. How long will it linger at zero before reversing?

by Mary-Sue Haliburton
Pure Energy Systems News

Seeing the powerful earthquakes such as the December 26th, 2004 event that triggered the tsunami disaster, people are looking for possible causes for the apparent instability of earth's crust. "End-times" alarmists and backyard researchers believe that the predicted imminent reversal of the earth's magnetic field may be a significant clue to these eschatological-scale events.

Scientists have been observing changes in the direction of earth's magnetic field which took place recently as well as in the distant past. NASA’s website features a map showing the gradual northward migration of the north magnetic pole in the past century and a half. Since more than double the time interval has elapsed since the last reversal, compared to the time lapse between the previous two pole reversals, some believe we may be overdue for the next north-south flip. (1,2) However, though the interval between reversals of the Earth’s magnetic field can be as short as 5,000 years, it can also be as long as 50 million years. There does not seem to be any logic or rule governing the planet’s behavior.

It is not only the direction but also the strength of this magnetic field that is a concern. In the time of dinosaurs, at an estimated 2.5 gauss, it was eighty percent stronger than it is now. This may have been one of the reasons such gigantic life forms thrived. It is now accepted that a catastrophic event ended the reign of giant reptiles. However, they did not re-evolve to equivalent dimensions. And the disappearance of mammalian “mega-fauna” in more recent times is still considered to be a mystery. The mastodons and mammoths would have towered over modern elephants. Why are there so few large terrestrial animals today?

The smaller average size of modern animals may be due to the gradual decline of Earth's "steady state" (as opposed to “pulsed”) magnetism. Thousands of years ago the Chinese, with their astute discovery of bio-electrical energy flows known as “meridians”, learned that magnetism promotes vigor in biological life. They used magnetic rocks in medical treatment. In the past century there has been a further decline of earth's magnetic field by another five percent down to only 0.5 gauss. This has led Dr. Dean Bonlie to identify a "magnetic deficiency syndrome" resulting from the biological stress caused by the weakening of this "energy base" for life. (3)

The weakening of earth’s magnetism is one of the factors believed to be predictive of a pole reversal. That magnetic field reversals have occurred in the past is confirmed in the geological record. What is unclear is how precisely the transition occurs, and what happens to life forms extant at the time of this pole flip.

Does the magnetic field drop to zero gauss? Dire predictions follow upon the heels of this theory. Electronic devices would all be at risk: there may be damage to, or complete loss of, all near-earth-orbiting satellites and possibly the space station itself. Effects on life forms could range from migrating birds losing their sense of direction to immune system decline and even widespread die-off from radiation-induced cancers.

Losing its protective magnetic envelope, the atmosphere would expand and become thinner, possibly leading to altitude sickness near sea level. No longer filtered out, deadly cosmic rays would kill most if, not all, living creatures on the surface. Only those living in deep caves would be safe. This scenario has prompted some to build underground bunkers in hopes of surviving.

Countering this frightening vision, NASA predicts that, rather than declining to zero gauss, the magnetic field would become disordered. Thus we might for short time have more than one north and south pole on the planet. This official scientific stance says that the magnetosphere which shields us from cosmic radiation would not entirely disappear either. Thus, while communications would be erratic and perhaps at times completely inactivated, humans would find ways to survive. However, there are dissenters in the ranks, pointing to the vast South Atlantic magnetic anomaly and radiation damage to satellites over that region attributed to weakening of the protective magnetosphere. (4)

The disorderly-flip theory is supported by evidence from geology that in past reversals the decline was not total. Lava flows that solidified at Steen's Mountain during a lengthy reversal process show that the magnetic poles wandered across the equator three times. Though strength of the field was reduced to about 20% of maximum, there is no record that it fell to zero gauss during that transitional period. (5)

The theory that activity in the turbulent molten outer iron core of the planet generates its magnetic field currently dominates scientific thinking. Stormy activity deep in the earth's outer core, believed to be filled with roiling convection flows of molten iron, is understood to generate the planet’s magnetic field. Such violent seething could affect the mantle as well, possibly disturbing the earth's crust and causing the quakes.

However, there is an alternate theory of how the magnetic field is generated. In his article, "Origin of the Earth's Magnetic Field", Ernest McFarlane outlines gaps in the molten-iron convection theory. He proposes a system of electronic cells in a crystalline metal core with hot spots of heavy metals releasing alpha and beta particles. Due to the high heat the alpha particles are unable to combine with the free electrons. "Consequently an electron current flow is produced and conditions are set up for the generation of current loops throughout the inner and outer core. ... magnetic fields are produced as a consequence, in accordance with the right hand rule of electromagnetic theory." (5)

Which theory is right? We may find out from experience sooner than we can come to amicable agreement, given the conflicting theories and computer models. The actual dynamics may include aspects of both, or new insights not yet fully developed.

The sun reverses its magnetic field like clockwork every eleven years at the peak of the sunspot cycle. The next solar flip is due in 2012. South-pointing magnetic flux moves from sunspots, which are intense magnetic loops near the equator of the sun, along “meridional flows” to the north magnetic pole, and vice versa. As the oppositely-directed charge accumulates at the poles the field declines, until eventually the reverse charge predominates.

Scientists point out that the heliosphere does not wink out of existence during this reversal. The sunspots are intense magnetic knots, much stronger than the star’s main field, which continue to spiral outward even when the main dipole field vanishes briefly. Though the solar magnetic reversal is not completely understood, the Ulysses space probe has sent back detailed data which has supplied answers to many questions. (6)

The mechanism that controls earth's field reversals may not be based on similar principles. For one thing, a planet does not seem to have any equivalent to the powerful sunspots. McFarlane refers to there being more than one north-south pole system and about 10% of the total field being involved in smaller extra fields. If these subordinate minor magnetic fields take up more of the magnetic activity during the main field’s decline, they might become active enough to sustain a minimal protective layer shielding the biosphere, even if the main dipole field declines to zero gauss. This could be important for our survival, as the Steen’s mountain lava flows indicate that the reversal took 4,500 years to be completed! (5)

IMPLICATIONS FOR HUMANITY’S ENERGY NEEDS

Whether the magnetic field is primarily molten-metal flow dynamics or electron current loops, or a combination of those and other factors, a magnetic pole reversal may be of significance to the search for clean energy generation and transportation. If earth magnetic anomalies become more frequent or are concentrated in certain areas, we could see disruption of existing electrical grids, even without the dramatic atmosphere expansion and radiation damaging to life and computers.

PES Network Inc. wants to encourage people in all geographical regions to participate in magnetic-pole data collection and reporting. A community-editable directory page at PESWiki.com has been created for this purpose. It is recommended that you first establish a “base line” by determining the accurate magnetic north reading for your location, and report the number of degrees and direction of any deviation from this norm. If you are able to access equipment to determine field strength as well, this additional data would be of interest too.

This data may be useful in helping inventors and researchers test the tolerance of Zero-point technologies, magnetic motors and other new generation systems in adverse situations. As we may have to live through ongoing magnetic disturbance for a long time, we will need to know whether the new systems will be robust under conditions of planetary pole reversal.

Ordinary citizens do not usually have access to instrumentation that would allow them to examine the deeper layers of the planet, nor the high atmosphere, nor the magnetospheres in space. However, if many people collect observations on magnetic field direction from different locations across the continent of North America, and indeed around the world, this data may become relevant in more ways than feeding "end-time" theorizing.

The subject is complex, and whichever scenario may be about to occur, some individuals have been taking note of unusually large fluctuations in the apparent position of the magnetic north pole. Using a large, stationary, home-built compass, one individual in western Canada noticed a ten-degree variation within a few days. This was so unusual that, concerned about a sudden pole shift, he described and published his observations, and asked for input.

No one else was seeing this rapid "pole shift".

On borrowing a very sensitive water-filled portable compass and quartering the area, he discovered that this was indeed a highly localized anomaly in which his domicile happened to be situated dead center. See his recorded readings at the link below. (8) He is now theorizing that the phenomenon may be a vortex related to the nearby extinct volcano Mount Ida. (9) Vortices have been known to occur in volcanic mountain areas, and in the past some have become tourist attractions.

Individual observations are of value, but need to be balanced by additional data from a much wider geographical area. Thus alarms about sudden general "pole shift" may be put to rest, and anomalies studied for what they are.

Ted Twietmeyer is one of those calling for volunteers to join in a non-profit effort (10) to track the magnetic pole shift -- or apparent pole shift. Summaries and links to this data would be appropriate for the above-mentioned PESWiki directory.
*Builds tin foil shelter*
 
an article by 'mary sue haliburton' ? !

a made up joke name if ever i heard one!
 
:shock: Source
By ALICIA CHANG
AP Science Writer
Dec 09 7:28 PM US/Eastern

SAN FRANCISCO - Earth's north magnetic pole is drifting away from North America and toward Siberia at such a clip that Alaska might lose its spectacular Northern Lights in the next 50 years, scientists said Thursday. Despite accelerated movement over the past century, the possibility that Earth's modestly fading magnetic field will collapse is remote. But the shift could mean Alaska may no longer see the sky lights known as auroras, which might then be more visible in more southerly areas of Siberia and Europe.

The magnetic poles are part of the magnetic field generated by liquid iron in Earth's core and are different from the geographic poles, the surface points marking the axis of the planet's rotation.

Scientists have long known that magnetic poles migrate and in rare cases, swap places. Exactly why this happens is a mystery.

"This may be part of a normal oscillation and it will eventually migrate back toward Canada," Joseph Stoner, a paleomagnetist at Oregon State University, said Thursday at an American Geophysical Union meeting.

Previous studies have shown that the strength of the Earth's magnetic shield has decreased 10 percent over the past 150 years. During the same period, the north magnetic pole wandered about 685 miles out into the Arctic, according to a new analysis by Stoner.

The rate of the magnetic pole's movement has increased in the last century compared to fairly steady movement in the previous four centuries, the Oregon researchers said.

At the present rate, the north magnetic pole could swing out of northern Canada into Siberia. If that happens, Alaska could lose its Northern Lights, which occur when charged particles streaming away from the sun interact with different gases in Earth's atmosphere.

The north magnetic pole was first discovered in 1831 and when it was revisited in 1904, explorers found that the pole had moved 31 miles.

For centuries, navigators using compasses had to learn to deal with the difference between magnetic and geographic north. A compass needle points to the north magnetic pole, not the geographic North Pole. For example, a compass reading of north in Oregon is about 17 degrees east of geographic north.

In the study, Stoner examined the sediment record from several Arctic lakes. Since the sediments record the Earth's magnetic field at the time, scientists used carbon dating to track changes in the magnetic field.

They found that the north magnetic field shifted significantly in the last thousand years. It generally migrated between northern Canada and Siberia, but it sometimes moved in other directions, too.

___

On the Net:

American Geophysical Union: http://www.agu.org
 
Re: Earth Stopped Wobbling/Geographical Pole Shift Imminent

TheMiddleman said:
Anyone who know's a bit more about the current science of this kind of thing care to enlighten me/us?



http://www.michaelmandeville.com/earthmonitor/polarmotion/2006_wobble_anomaly.htm

Is there a more scientific source for that?

Not that I'm saying their wrong but I'd rather have more info from NASA or the ESA rather than a group of Cayce fans.

[edit: And thread merged with the main pole reversal thread - if you are looking for general info see the rest of the thread for previous discussion.]
 
Is there a more scientific source for that?

Not that I'm saying their wrong but I'd rather have more info from NASA or the ESA rather than a group of Cayce fans.

LOL. Sorry... I should have been more specific. I meant about the science of the erath actually stopping wobbling on it's axis in the last couple of weeks... not the Cayce stuff.

TheMiddleman
 
TheMiddleman said:
Is there a more scientific source for that?

Not that I'm saying their wrong but I'd rather have more info from NASA or the ESA rather than a group of Cayce fans.

LOL. Sorry... I should have been more specific. I meant about the science of the erath actually stopping wobbling on it's axis in the last couple of weeks... not the Cayce stuff.

So was I - I'd need to see a more reliable source. I would imaigne this might be rather big news.
 
Yeh I saw this earlier, and felt the same if the data is correct it is pretty big news, I think, but the source is dubious the Cacians have a history of wrongness to say the least. It's got me flummoxed because of a total knowledge gap :?
 
I know I was going to say from another dubious source but thought it needed no saying :lol:
 
Geomagnetic flip may not be random after all

21 March 2006

One of the most fascinating natural phenomena on Earth is the flipping of its magnetic field, which has occurred hundreds of times in the last 160 million years. When the magnetic field flips, the North Pole becomes the South Pole and vice versa. The last time this happened was some 780,000 years ago, so we could be heading for another reversal soon. Now, physicists in Italy have found that the frequency of these polarity reversals is not random as previously thought but occurs in clusters, revealing some kind of "memory" of previous events (physics/0603086).

Although a full geomagnetic polarity reversal can take thousands of years to complete, the implications could be enormous. As well as affecting the migration trajectories of birds and other animals, the disruption to the Earth's magnetic field could expose the Earth to hazardous cosmic rays -- a scenario that some researchers have linked to mass extinction events like the one that wiped out the dinosaurs around 65 million years ago. Geoscientists believe that our planet's internal magnetic dynamo is responsible for pole reversals, but the actual mechanism is not well understood.

Previous analyses assumed that the number of times the poles have reversed over last 160 million years follows a Poisson distribution, implying that the events are random. The Poisson distribution tells you the probability of a number of events occurring in a fixed time if the events are independent and the average rate is known. A good example of the Poisson distribution in physics is the likelihood of unstable radioactive nuclei decaying in a certain period.

Now, a team of physicists led by Vincenzo Carbone of the University of Calabria have discovered that the sequence of polarity reversals can be well described by a Lévy distribution instead. In contrast to Poisson statistics, the Lévy distribution describes stochastic processes that are characterised by the presence of "memory" effects -- or long-range correlations between the events in time. Lévy distributions are widely used to study many critical phenomena, such as earthquakes, and also when analysing financial data. The researchers obtained their results by careful statistical analysis of different sets of paleomagnetic data containing estimates of when the Earth's poles reversed.

"The result means that polarity reversals are not random events that are independent of each other," explains team member Fabio Lepreti. "Instead, there is some degree of memory in the magnetic dynamo processes giving rise to the reversals," he says. "We hope that our work will serve as a useful reference point for models that aim to describe the phenomenon of pole reversal." The Italy team now plans to build new dynamic models to describe the field reversal sequences in a simple way, so that the physical mechanisms that trigger pole reversals can be more easily explained.

http://physicsweb.org/articles/news/10/3/15/1
 
Space weather Look down, look up, look out!

Space weather

Look down, look up, look out!

May 10th 2007 | KANGERLUSSUAQ, GREENLAND
From The Economist print edition


The weather in space is controlled by events at the centre of the Earth. A pity, then, that the magnetic field generated there may be about to go into reverse


GREENLAND was discovered without the use of magnetic compasses. The Viking longboats that arrived here in 982 relied on the stars and the sun to maintain their orientation. But it was the compass (a Chinese invention) that enabled later European navigators to bestride the world. It was the compass, too, which revealed that the Earth itself has a magnetic field and thus led to the first serious question about the planet's internal structure: what is down there that generates this field?

Such a question is not merely academic. Besides directing compasses, the Earth's magnetic field reaches out into space to direct the flow of the solar wind around the planet—forming a structure called the magnetosphere (depicted above). When the wind hits this field it creates a shock wave known as the bow shock. Most of the protons and electrons of the wind go round this shock wave, and lots of dangerous radiation from the sun is thus diverted away from the Earth.

There is, however, a growing body of evidence that the Earth's magnetic field is about to disappear, at least for a while. The geological record shows that it flips from time to time, with the south pole becoming the north, and vice versa. On average, such reversals take place every 500,000 years, but there is no discernible pattern. Flips have happened as close together as 50,000 years, though the last one was 780,000 years ago. But, as discussed at the Greenland Space Science Symposium, held in Kangerlussuaq this week, the signs are that another flip is coming soon.

One of those signs is that the strength of the field has been falling by 5% a century recently. A similar (though more rapid) diminution accompanies the reversing of the sun's magnetic field, which happens every 11 years or so. Other evidence comes from old navigation records. Researchers such as Nils Olsen, of the Danish National Space Centre, have used such records to chart the growth of patches of abnormal magnetism. They are able to do so because these records use both compass bearings and astronomical observations to locate a vessel. The changing relationship between the two shows that patches of abnormal magnetism have been growing off south-east Africa and in the South Atlantic.

Just when the magnetic field will flip is impossible to predict from what is known at the moment; the best guess is that there are still several centuries to go. Nor is it clear how long its protective shield will be down. (The record in the rocks is little help, since a geological eyeblink represents many human lifetimes.) But understanding how the magnetosphere works now should help to deal with the consequences if and when it vanishes.



Bright lights
One of the pioneers of the field was Dr Olsen's colleague Eigil Friis-Christensen. Thirty-five years ago he took a boat north along the west coast of Greenland. As he travelled, he set up instruments called magnetometers to measure electric currents in the upper atmosphere. These magnetometers and their successors have played the role that barometers did for early weather forecasters. Then, the pattern of pressure changes the instruments recorded tracked the passage of storms in the atmosphere. Now, it is storms in the magnetosphere that are recorded.

Dr Friis-Christensen's own work has focused on a structure known as the “cusp”. This separates the magnetosphere's two main compartments: the crown, a round projection that stretches sunwards by about five times the diameter of the Earth, and the tail, which is shaped as its name suggests and runs far into space on the Earth's night time side.

The cusp is responsible for the famous auroras that grace high latitudes. This is because it is at the cusp that magnetic field-lines stream down towards the ground, acting as paths for electrons and protons that have slipped past the bow shock. When these particles hit the upper atmosphere they generate light in the same way that electrons from the cathode of an old-fashioned television set do when they hit the phosphorescent dots of the screen.

The famous night-time auroras (borealis in the north, australis in the south) are the result of particles streaming in from the tail. But particles come in from the crown, as well, forming invisible daytime auroras that Dr Friis-Christensen was among the first to study.

Another Greenland-based instrument, a few miles from Kangerlussuaq, has pinned down more details about the cusp. The Sondrestrom Upper Atmospheric Research Facility has a 32-metre-wide radar dish. It measures conductivity from an altitude of 60km to 600km and has helped define the cusp's circuitry. That is important because, although it is not technically part of the atmosphere, the plasma of charged particles in the magnetosphere experiences what might be (and indeed often is) referred to as weather.

Like the weather on Earth, this space weather has consequences. If it gets nasty, communications satellites may be knocked out and radio communications within the atmosphere disrupted. In extreme circumstances, power grids may go down, too. Foul weather in space is also bad news for astronauts. A bad storm could kill an unshielded individual. But although the source of such foul space weather is known—it happens when giant flares on the surface of the sun pour out more protons and electrons than normal—the details depend on structures within the magnetosphere that are only now coming under scrutiny. Sometimes storms drift past the Earth with little impact. On other occasions they pummel the magnetosphere's crown to about half its normal distance from the Earth's surface. Furthermore, the magnetosphere's structure is layered, like an onion. The same type of particle can take on entirely different characteristics, depending on which layer it is in. The art of forecasting space weather is in its infancy.

How much longer it will remain within Dr Friis-Christensen's purview, though, is moot. Barometers are now curiosities, as satellite-based forecasting has taken over. The same thing is about to happen to space meteorology. Five satellites, collectively called THEMIS, that were launched in mid February, may make his magnetometers as old-fashioned as the mahogany instrument hanging in a hotel lobby

http://www.economist.com/science/displa ... id=9143913
 
Oceans charge up new theory of magnetism
A radical new idea may revolutionise our understanding of one of the most vital forces on Earth
Jonathan Leake

Earth's magnetic field, long thought to be generated by molten metals swirling around its core, may instead be produced by ocean currents, according to controversial new research published this week.

It suggests that the movements of such volumes of salt water around the world have been seriously underestimated by scientists as a source of magnetism.

If proven, the research would revolutionise geophysics, the study of the Earth’s physical properties and behaviour, in which the idea that magnetism originates in a molten core is a central tenet.

Earth’s magnetic field is vital for life, extending tens of thousands of miles into space and protecting the planet against radiation that would otherwise burn away the atmosphere and oceans.

However, its origin was a mystery until early last century when Albert Einstein said understanding the phenomenon was one of science’s most important tasks. This provoked a debate which concluded with scientists agreeing that magnetism must originate in the Earth’s core.

“Everyone accepted this, but in reality there has never been any proof,” said Gregory Ryskin, associate professor of chemical and biological engineering at Northwestern University in Illinois. “It is just an idea we have accepted for a long time without questioning it enough.”


His research suggests that Earth’s magnetism is actually linked to ocean movements. The salt in seawater allows it to conduct electricity, meaning it generates electrical and magnetic fields as it moves.

The findings, published by Britain’s Institute of Physics’s New Journal of Physics, will cause a fierce scientific debate.

Existing theories explain Earth’s magnetism by suggesting that the centre of the planet comprises a white-hot solid iron ball about 1,500 miles in diameter, surrounded by an outer shell of liquid metal a further 1,400 miles thick.

As the liquid iron in that shell is heated by the inner core it becomes less dense and rises upwards, to be replaced by cooler material from above.

The resulting swirls of molten metal create electric currents that in turn produce the planet’s magnetic field, the conventional theory suggests.

The big problem with this idea is that it is almost impossible to obtain experimental evidence because the Earth’s core is so inaccessible. Indirect approaches, such as computer modelling, have thrown up many inconsistencies.

Ryskin approached the problem differently, by looking at the way Earth’s magnetic field undergoes constant changes, growing stronger in some regions and weaker in others. This phenomenon, known as variation, also sees gradual shifts in the locations of the north and south magnetic poles.

Scientists have always linked variation with turbulence in the outer core, but Ryskin suggests it actually correlates with changes in ocean circulation. In the north Atlantic, for example, changes in the strength of currents were matched by sharp changes in magnetic fields.

One idea is that changes in ocean circulation may explain the curious reversals shown by Earth’s magnetic field, in which the north and south magnetic poles suddenly flip over. This last happened 780,000 years ago.

This could also be linked to tectonic plate movements that have shifted the world’s land masses around the globe, forcing ocean currents to adopt entirely new routes.

If Ryskin is right, then climate change, predicted to alter the strength and course of ocean currents, could also alter the planet's magnetic field.

Ryskin emphasises that such suggestions need much more research, but some other physicists have been quick to recognise its implications. Raymond Shaw, professor of atmospheric physics at Michigan Technological University, said it could make “the ruling paradigm of geophysics irrelevant”.

Others are sceptical. Andrew Jackson, professor of geophysics at the Federal Institute of Technology in Zürich, Switzerland, and an expert in planetary magnetism, said the magnetic fields generated by moving seawater would be thousands of times smaller than what is observed. “I think the calculations are wrong,” he said.

Kathy Whaler, professor of geophysics at Edinburgh University, would not comment directly on Ryskin’s work as she had not read it.

However, she said the idea that the Earth’s molten core produced its magnetic field was “well founded”. She said: “We know from seismology what the Earth’s structure is, and that it is likely to contain molten iron at high temperatures flowing around a solid core.”

http://www.timesonline.co.uk/tol/news/u ... 493481.ece
 
So, should I buy more or sell my shares in compass manufacturers?
 
Ginando said:
So, should I buy more or sell my shares in compass manufacturers?
Well, navigators have long known about compass variation (and deviation, which is something different) and how to compensate for it.

But if Magnetic North does go on an unpredictable walkabout, or disappears altogether, I expect we'll have bigger problems to deal with than stocks and shares, as the Earth would lose its magnetic protection from solar storms, etc.
 
rynner2 said:
Ginando said:
So, should I buy more or sell my shares in compass manufacturers?
Well, navigators have long known about compass variation (and deviation, which is something different) and how to compensate for it.

But if Magnetic North does go on an unpredictable walkabout, or disappears altogether, I expect we'll have bigger problems to deal with than stocks and shares, as the Earth would lose its magnetic protection from solar storms, etc.

In that case I'll sell everything else and buy shares in sun burn lotion manufacturers :lol:
 
think its strange that the french plane has crashed in the very place the earth field is weakest ,between mexico and africa

do you think it might have been hit by a solar storm ,killing the electrics.since its high up it would be more at risk from such an event wouldnt it.

sorry this is in the wrong thread but the posts are in here about this ..
 
fatcat said:
think its strange that the french plane has crashed in the very place the earth field is weakest ,between mexico and africa

do you think it might have been hit by a solar storm ,killing the electrics.since its high up it would be more at risk from such an event wouldnt it.

sorry this is in the wrong thread but the posts are in here about this ..

If my understanding of this website is correct, then there doesn't appear to be high activity. Indeed sunspot activity is currently at a very low ebb apparently.

http://www.lmsal.com/solarsoft/last_events/
 
we still get aurora and solar wind even at the solar min.
im quite sure any planes electrics isnt really cut out for this.
 
53 degrees shift in a single year!

Evidence of second fast north-south pole flip found
http://www.physorg.com/news202971192.html
September 6th, 2010 in Space & Earth / Earth Sciences

(PhysOrg.com) -- The Earth's magnetic poles flip around every 200,000 years or so, with north becoming south and vice versa. Normally, the process takes 4-5,000 years and it ought to be impossible for the flip to be much faster, if models of the Earth's core are correct, but now for the second time evidence has been found of a flip that appears to have taken only a few years.

The first time evidence was discovered of a rapid geomagnetic field reversal was in 1995 when well-preserved lava flows were found at Steens Mountain in Oregon in the US. Research on the rocks by a team led by geologist Scott Bogue of the Occidental College in Los Angeles revealed the lava flow had an unusual magnetic pattern that suggested the magnetic field had been shifting over 10,000 times faster than normal, at six degrees a day. The magnetic patterns are preserved within the magnetic crystals in the lava, formed as the lava flow cooled.

The first findings remained controversial and many scientists have challenged the fast flip-flop theory, but now Bogue and colleague Jonathan Glen of the US Geological Survey have found evidence in ancient lava rock in Battle Mountain, Nevada of a second fast flip, dated around 15 million years ago.

The record in one particular lava flow in Nevada suggests the magnetic field moved by 53 degrees in a single year. The lava started to cool, but was then heated again within a year as it was buried under fresh lava. The crystals in the rock were re-magnetized by the fresh lava, producing a shift of 53 degrees. This finding could mean the poles swapped over a period of only four years, but Brogue said it could also suggest there was a rapid acceleration period within the steady movement of the field.

According to some geologists a polarity reversal is overdue, since the Earth’s magnetic field has been weakening for the last century, and the last stable reversal was about 780,000 years ago. Even if it was a super-fast flip-flop, however, it would not be noticeable to most people. No one is certain why such reversals take place, although many scientists believe they are connected in some way with the convective movements of the liquid iron in the Earth’s outer core.

The findings are due to appear in Geophysical Research Letters.

More information: Bogue, S. W et al., Very rapid geomagnetic field change recorded by the partial remagnetization of a lava flow, Geophysical Research Letters, doi:10.1029/2010GL044286 , in press.
 
Adjust your compass now: the north pole is migrating to Russia
Movement of the magnetic north is causing problems for aviation, navigation and wildlife
By Guy Adams in Los Angeles
Sunday, 6 March 2011

It sounds unlikely but it's true: the magnetic north pole is moving faster than at any time in human history, threatening everything from the safety of modern transport systems to the traditional navigation routes of migrating animals.

Scientists say that magnetic north, which for two centuries has been in the icy wilderness of Canada, is currently relocating towards Russia at a rate of about 40 miles a year. The speed of its movement has increased by a third in the past decade, prompting speculation that the field could be about to "flip", causing compasses to invert and point south rather than north, something that happens between three and seven times every million years.

Already the phenomenon is causing problems in the field of aviation. Tampa International airport in Florida has just spent a month renaming its three runways, which in common with those at most US airports are identified using numbers that correspond to the direction, in degrees, that they face on a compass. "Everything had to be changed; it was a huge project," Brenda Geoghagan, a spokeswoman for the airport, said.

The current rate of magnetic north's movement away from Canada's Ellesmere Island is throwing out compasses by roughly one degree every five years, prompting the US Federal Aviation Administration to re-evaluate runway names across the country every five years. Similar changes were recently made to runways at Fort Lauderdale and Palm Beach.

Geologists believe that magnetic north pole (which is different from the true North Pole, the axis on which the Earth spins) moves around due to changes in the planet's molten core, which contains liquid iron. They first located it in 1831, and have been attrying to follow its progress ever since.

Records indicate that the pole's location barely moved in the early decades, but in about 1904, it began tracking north-east at a rate of about nine miles a year. That speed increased significantly from about 1989, possibly because of a "plume" of magnetism deep below ground. The pole is now believed to be heading towards Siberia at about 37 miles each year. "Earth's magnetic field is changing in time. And as far as we know, it has always been changing in time," geophysicist Jeffrey Love of the US Geological Survey in Colorado told Discovery News, which investigated the issue last week.

GPS systems, which rely on satellites, have replaced compasses as the means by which the majority of professional navigators orientate themselves. But compasses are still valuable, and are widely used by hikers and other amateur map-readers. In some environments, such as underwater or beneath ground, which cannot be reached by satellite signals, they remain the only option. The oil industry, which uses magnets to determine which angle it should drill into the earth, needs to keep track of the exact location of magnetic north.

Birds that fly south for the winter, along with migratory sea creatures, could face confusion. Long-living animals, such as whales and turtles, may in future be required to recalibrate their navigational instincts.

Despite the cost and inconvenience of altering runway names, not to mention the indignity of losing magnetic north to Russia, inhabitants of North America stand to benefit from the changes in at least one respect: it will give them more opportunities to observe the aurora borealis.

No one can predict the impact of "polar reversal", during which magnetic north and south reverse, since one hasn't happened for 780,000 years, the longest stable period in the past 5 million years. Some geologists think we could be about to find out, though: they believe that the current changes to magnetic north could be the early stages of a "flip". But Mr Love says we shouldn't be too concerned. "Reversals typically take about 10,000 years to happen," he said. "And 10,000 years ago civilisation did not exist. These processes are slow, and therefore we don't have anything to worry about."

http://www.independent.co.uk/news/scien ... 33610.html

"..therefore we don't have anything to worry about": why does that worry me?
:?
 
This deals with the cause of Earth's magnetic field, and how it changes:

Horizon: The Core
BBC2 from 9:00pm to 10:00pm

For centuries we have dreamt of reaching the centre of the Earth. Now scientists are uncovering a bizarre and alien world that lies 4,000 miles beneath our feet, unlike anything we know on the surface. It is a planet buried within the planet we know, where storms rage within a sea of white-hot metal and a giant forest of crystals make up a metal core the size of the Moon. Horizon follows scientists who are conducting experiments to recreate this core within their own laboratories, with surprising results.


See also:

Magnetic mysteries of Earth's Core

http://www.bbc.co.uk/news/uk-14678002
 
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