North Magnetic Pole Moving East Due To Core Flux 346
National Geographic is reporting that the migration of Earth's magnetic pole has accelerated again and is now racing in Russia's direction at a blazing 40 miles per year. This movement began in earnest around 1904 at about 9 miles per year and has been accelerating since. "Geologists think Earth has a magnetic field because the core is made up of a solid iron center surrounded by rapidly spinning liquid rock. This creates a 'dynamo' that drives our magnetic field. Scientists had long suspected that, since the molten core is constantly moving, changes in its magnetism might be affecting the surface location of magnetic north. Although the new research seems to back up this idea, Chulliat is not ready to say whether magnetic north will eventually cross into Russia. 'It's too difficult to forecast,' Chulliat said. Also, nobody knows when another change in the core might pop up elsewhere, sending magnetic north wandering in a new direction."
What, no mention of geomagnetic reversal? (Score:5, Informative)
The poles are flipping? (Score:5, Informative)
This article covers it...
http://scienceblogs.com/highlyallochthonous/2009/02/is_the_earths_magnetic_field_a.php [scienceblogs.com]
I've heard it from several sources though, they have geological proof that the earths magnetic field has been periodically flipping and reversing its polarity, and that it does this at periodic intervals, and that we are in fact due for a flip any millenia now.
Re:and the south? (Score:3, Informative)
and traditional compasses are nearly useless during the transition period as the north/south polarity breaks up into mini-poles, which are regional and in constant flux.
Re:How convenient (Score:5, Informative)
GPS can determine heading in two ways.
The first way only works if the GPS receiver is moving, in which case it can calculate a course based on your current and previous positions. This course is then approximately your heading - although it can include a pretty large error due to drift (when in a ship or an airplane).
The second way only works if you have two (or more) GPS receivers a reasonable distance away from each other (say, fore and aft or port and starboard on a large enough ship, or in the tips of the wings of an airplane). Then the GPS device has two positions, and the line through them is your heading (if they're placed fore and aft) or your heading + or - a constant angle (for example, + or - 90 degrees if they're places port and starboard).
Re:What, no mention of geomagnetic reversal? (Score:5, Informative)
> It's moving East, not South.
Hmmm.... *BRAIN STRAIN*.... ummm... wouldn't any direction from the north pole be south?
Since magnetic North does not coincide with true North, then magnetic North can move East by simply circling true North in a counter-clockwise direction, as viewed from above the (true) North Pole.
North, South and Reversal (Score:5, Informative)
TFA is only about north. South is moving also, but not nearly as much. Two magnetic poles are not a rigid dipole. Maybe in the core, but at the surface they're fairly independent. Given this, it's quite possible that past geomagnetic events were not 'reversals' with north and south sliding past each other and popping out the other side. Rather north and south might wander far enough out of opposite that the Earth's external magnetic field is far off center, and/or very strong over some parts but weak over others. Conceivably they could 'collapse' by becoming too close. The magnetic field would appear to go away although the generator (and whatever drives it) is still operating. I think this makes more sense than the direct reversal in that it assumes the generator to stop operating, which I find unlikely, and start again of its own accord, which smacks of a planetary "and then a miracle occurs". The data does support this hypothesis as being at lest possible. In 2005 magnetic north of 500 miles from true north, while magnetic south was 1750 miles from true south. Either the dipole is off center, which contradicts the generator idea, or the dipole is bent.
Yeah, it's accelerating, just look at these data! (Score:2, Informative)
Re:The poles are flipping? (Score:5, Informative)
2.5 All ships of 500 gross tonnage and upwards shall, [...] have:
.1 a gyro compass, or other means, to determine and display their heading by shipborne non-magnetic means [...]
.2 a gyro compass heading repeater, or other means, to supply heading information visually at the emergency steering position if provided;
.3 a gyro compass bearing repeater, or other means, to take bearings [...]
Gyrocompasses [wikipedia.org] are useful for many other reasons: they point to true north instead of magnetic north, which means you don't have to correct for magnetic declination [wikipedia.org] (the difference between true north and magnetic north) and magnetic deviation [wikipedia.org] (the difference between compass north and magnetic north, an error caused by local magnetic influences such as the steel in a ship's construction). They can also give your heading digitally, which means you can connect repeaters to it, and autopilots etc. can use its output.
From
this page [navis.gr]:
Almost every naval vessel and merchant ship today carries at least one master gyrocompass, installed in its own gyro room. A transmission system links the master gyrocompass to "repeaters." These are used on the ship for such purposes as steering, position finding, and course recording.
Re:Yeah, it's accelerating, just look at these dat (Score:2, Informative)
Re:In soviet russia... (Score:2, Informative)
Especially since the magnetic north pole is actually near the south pole. This is why a magnetic north pole on a compass points north towards the Earth's magnetic south pole.
Re:How convenient (Score:5, Informative)
Re:How convenient (Score:3, Informative)
There's also the gyrocompass [wikipedia.org], which finds true north, and which doesn't depend on the earth's magnetic field. It'd work on Mars.
might not have GPS (Score:5, Informative)
Without a magnetic field to stop the solar wind, satellites tend to die.
Granted, GPS is military and not LEO, so it might be built a bit better than most.
Re:How convenient (Score:5, Informative)
I highly doubt a handheld GPS would have an inbuilt gyrocompass. Those things need constant power to keep the gyroscope from slowing down, and if the power fails you have to recalibrate it, for which you need to know your exact heading. Which is why, on ships, they usually have their own backup power source (usually a battery) in case the main and backup power generators are down.
That, and they're pretty big and heavy. They even get their own room [navis.gr] (I also linked to this page in another post about gyrocompasses I made a few minutes ago):
Almost every naval vessel and merchant ship today carries at least one master gyrocompass, installed in its own gyro room.
Re:The poles are flipping? (Score:5, Informative)
A lot of pilots use the earth's magnetic field for navigation. When flying around under visual flight rules in an analog cockpit (which make up the majority of general aviation aircraft), the magnetic compass backs up the gyro-based heading indicator. Every 15-20 minutes, the heading indicator is realigned with the compass heading when in straight and level, unaccelerated flight due to the effects of precession, making that magnetic field very important. Even in a glass cockpit, the FAA requires a backup magnetic compass in case of computer or electrical failure.
Re:Moving east? (Score:3, Informative)
I'm bored so I'll throw in. Please don't think I'm condescending. I'm just stuck in a hotel room.
People often get confused here. What is shifting is the magnetic pole, not the geographic pole. Both the North magnetic and South magnetic poles are shifting at some rate, the northern one moving more rapidly than the southern one. The geographic pole is not at issue here, only the magnetic one. The physical geographic north pole coincides with the rotational axis of the planet which "wobbles" by a known amount (http://en.wikipedia.org/wiki/Precession)
The magnetic poles are both effects of some deeper physical process that occurs within the planet. The popular theory at the moment is that the Earth contains an iron core which is rotating rapidly, causing the magnetic field we know and love. It has been sufficiently proven (for a lot of people) that the poles:
1. Have shifted multiple times throughout history
2. Are not rigidly dipolar. Meaning that the southern magnetic pole is not directly opposite of the northern magnetic pole.
You can expect the magnetic poles to shift more rapidly as time goes on until they again stabilize at some point in the future.
As far as the glacial theory goes, what you've read concerns various theories that the outer crust of the Earth, known as the asthenosphere (http://en.wikipedia.org/wiki/Asthenosphere) has shifted rapidly and on a global scale. These shifts would present themselves catastrophically and have massive global effects, such as causing the "then" apparent geographic poles to rapidly move "somewhere else". It should be noted that only the outer crust of the planet would be expected to move (and everything on the crust along with it). The rest of the planet would maintain its previous rotational axis. This theory, while tantalizing, is not widely accepted among most geologists for a number of reasons. Refer to the following for more on that:
http://survive2012.com/index.php/how-do-poles-shift.html
http://en.wikipedia.org/wiki/Graham_hancock
I love those theories, they're interesting as heck, but I have to admit the evidence to support them is more than a little thin.
Re:Moving east? (Score:5, Informative)
Look, educate yourself on the difference between the MAGNETIC north pole (the one defined by the magnetic field, probably caused by movement in the molten core of the earth, who's only serious influence on the earth is the direction compasses (including the ones inside a bird's head) point) and the GEOGRAPHIC north pole (the one defined by the rotation of the earth as a whole, which defines the coldest parts of the world).
The MAGNETIC north pole drifts constantly and flips occasionally (though not what one might call "regularly"). This is not accompanied by any cataclysmic extinction event, and takes place over dozens or even hundreds of years. It did not happen during the Mayan or Egyptian cultures, and unless you think they were sending probes to the mid-Atlantic ridge they were unlikely to even be aware of it much what able to predict it better then modern science (which says the field will probably begin flipping sometime in the next 10 to 200,000 years). The magnetic north pole has no influence over how cold it is in any given place on earth.
The GEOGRAPHIC north pole doesn't drift appreciably, or flip - ever. If it did flip, the most obvious sign would be that the sun would rise in what we currently think of as the west, and set in what is now the east. Also, all the stuff that got flung into space as the earth stopped spinning suddenly and then started up again in the opposite direction. Or if it happened more gradually, summers and winters would gradually get more extreme until the entire world spent half of every year (as opposed to half of every day) in the sun, and the other half in the shade, at which time the trend would reverse until it came to a rest exactly as it is now but with the sun rising in what was the west and setting in what was the east. Both methods would take similarly ludicrous amounts of energy, and probably kill most large animals and plants.
Re:What about the South Pole? (Score:5, Informative)
So, does the South pole shift as well?
Yes [aad.gov.au].
To where?
Antarctica isn't divided up into countries, so it's moving from Antarctica to Antarctica*. That's like saying it's gone from the middle of nowhere (with penguins) to also the middle of nowhere (with penguins): there's just no way of making that an attention grabbing story, despite the penguins.
*To be technical, magnetic South is near the edge of the sea ice rather than on the continent, which means it's moving from a really cold bit of ocean to another, slightly less cold bit of ocean. While that does entail more penguins, it's still not that interesting.
Re:Moving east? (Score:2, Informative)
The GEOGRAPHIC north pole doesn't drift appreciably, or flip - ever.
Maybe not but it does exhibit axial precession which has a period of approximately 26,000 years [URL="http://en.wikipedia.org/wiki/Axial_precession_(astronomy)"]
Re:Moving east? (Score:5, Informative)
I've also read postulations that glaciers were not caused by 'ice ages' per se, so much as they were the remains of the north pole ice cap after a shift.
Umm ... Are you aware that the reason it's cold at the poles has nothing to do with the earth's magnetic field, but rather the weaker intensity of sunlight at high latitudes? Were you sick on that day in third grade?
It's a particularly interesting topic if you look at the archaeological records of our past; specifically, the polar relation/geographic locations of Egyptian, Mayan, and other ancient peoples' religious/whatever sites. They seem to predict a pole shift, or at least make subtle suggestion to one occurring in the past.
The last geomagnetic reversal took place 780,000 years ago. So, bzzt, no.
Please turn in your geek card on the way out.
Re:Not good for Russia (Score:4, Informative)
Re:North, South and Reversal (Score:3, Informative)
Current thinking is not that the generator stops and starts, nor that the poles cross over in the core or even wander along the surface until they flip. The idea is that the dipole field weakens while higher order fields intensify, so we end up with multiple poles all over. Eventually the dipole field strengthens again, with the opposite polarity.
Re:North Pole (Score:4, Informative)
How are Soviet Russia jokes even funny anymore?
As a meme it's over used and lacking in hilarity. In reference to this particular story though, it could not have been better played.
Re:Moving east? (Score:3, Informative)
The GEOGRAPHIC north pole doesn't drift appreciably, or flip - ever.
It does drift, slowly and not by very much, but the main reason it doesn't flip over time (well, change its orientation massively with respect to the rest of the solar system) is that we've got a very large satellite to stabilize us. It's been conjectured that without it, there would be no higher life on Earth because the climate would be just too nasty. Thanks, Moon!
Re:Software - a perfect analogy! (Score:3, Informative)
Re:What, no mention of geomagnetic reversal? (Score:3, Informative)