NORTH POLE?: There are at least seven different possible definitions of the North Pole, including the conceptual point in the Arctic Ocean that corresponds to where all the lines of longitude converge on a map.
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You may think of the North Pole only as the top of the world—its northernmost point and, if you're younger, Santa's home. But it turns out there are a host of "north (and south) poles" on our planet.
First, and most simply, there is a town in Alaska called "North Pole" which isn't near any of the other north poles (but it does get snow and receives a lot of mail addressed to Santa Claus). Then there is the geographic north pole, also known as "true north." This is the spot in the Arctic Ocean where all the man-made lines of longitude converge on a map as well as the conceptual point on the ice-encrusted waters that countless explorers sought to stab with their national banner–bearing flagpoles, beginning in 1827 with British rear admiral, Sir William Edward Parry.
Somewhat related to the geographic north pole is the considerably less famous instantaneous north pole, where Earth's rotational axis meets its surface, as well as the celestial north pole, where the axis spears the night sky (in an imaginary extension kind of way). The instantaneous north pole is not fixed. Rather, it moves in an irregular circle caused by "the Chandler wobble"—named for astronomer Seth Carlo Chandler, who discovered in 1891 that our planet wobbles as it rotates. His discovery gives rise to the "north pole of balance," which lies at the center of this circle.
All of this jargon separates into unique, if not pedantic, definitions. So although they all share the term "north pole," each has clearly staked out its own semantic territory. The same cannot be said, however, of the last two "north poles" in this rundown, and both relate to Earth's very real magnetic field, which is generated by fluid motion inside the planet's core. That motion—affected by Earth's rotation—sets up a naturally occurring electric generator that sustains the magnetic field.
The magnetic pole describes the two locations (north and south) where the planet's magnetic field is vertical. So if you're standing over the north magnetic pole with a compass, the needle would dip and try to point straight down—hence its other name: the magnetic dip pole. Over the south magnetic pole, your compass needle would point upward.
But there is another magnetically based north pole: the north geomagnetic pole. "One thing that's very confusing is the fact that there's a magnetic pole and a geomagnetic pole and that they're different," says Stefan Maus, a geomagnetic field modeler at the National Oceanic & Atmospheric Administration's (NOAA) National Geophysical Data Center. "It's a historical and slightly outdated definition."
The geomagnetic poles are almost an artifact of reducing Earth's complex and varied magnetic field to that of a simple bar magnet, or dipole. "The only thing that we really want to know is where the field is really vertical," Maus says. "This other pole, which is just an approximation, is generally not very useful and often leads to confusion." So while the north dip pole lies in Northern Canada, the northern dipole is roughly off the northwest coast of Greenland.
But the geomagnetic pole is useful, if you're in space, argues Jeffrey J. Love, a U.S. Geological Survey geophysicist. The farther away from Earth you get, the more its magnetic field actually does act like a dipole, or a bar magnet—even if in reality it is no such thing.
"A space physicist usually thinks in terms of this tilted dipole that the earth has," Love says, "whereas a navigator would probably be more interested in the magnetic dip poles."
To further confuse things the dip poles move around—sometimes with daily frequency. The north magnetic pole in recent years has started shifting quickly toward Siberia. Its annual movement has accelerated from 10 to 50 kilometers (6.2 to 31 miles), says Larry Newitt, an emeritus scientist with the Geological Survey of Canada, who has pegged the pole's location on many expeditions since 1973.
And here's something to add even more confusion to the north magnetic pole (aka dip pole) versus north geomagnetic pole (aka dipole): the magnetic pole in Earth's northern hemisphere acts like the south pole of a bar magnet.
"If you look at the north pole of the bar magnet you have the field lines going from the north pole to the south pole, but for the earth it's exactly opposite," Maus explains. So the north magnetic pole is where the earth's magnetic field lines pull toward the planet, acting like the south pole of a bar magnet.
From a physics standpoint, then, the north needle of a compass (or any magnet) points to what is physically—but not in name—the south magnetic pole of the earth, in other words, in the direction of the Arctic.
"The north pole of your bar magnet is attracted to the north [magnetic] pole of the earth," Maus adds, the reverse of the usual situation in which like poles on magnets repel one another. "That is why some people have suggested that to avoid this confusion we should call the north magnetic pole the 'north seeking pole.'"
Whether that would add or subtract from the confusion remains unclear. What is clear is that—even in Santa Claus–related matters—one must be very precise in specifying exactly what one is talking about when referring to the "north pole."
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Reply | Report Abuse | Link to thisWhy it wasn't mentioned that the North magnetic pole is shifting? It strated moving in August of 1999 and since that time shifted 200 km to the south of the point it previously was. Yes, now it's in Northern Canada. But what is the explanation of that phenomena?
Reply | Report Abuse | Link to thisThe North Magnetic Pole is constantly moving...it did not just start in 1999.
Reply | Report Abuse | Link to thisThis is caused by a number of factors including dynamo currents in the Earth's core and electric currents in the Earth's ionosphere and magnetosphere.
The magnetic north pole is in the geographic southern hemisphere, which is actually incorrectly depicted in most textbooks.
Reply | Report Abuse | Link to thisTrue. The north pole on a compass needle is really pointing at the magnetic south pole. Which currently is geographically in the northern hemisphere. Though this article does state as much. Something not mentioned is that the Magnetic poles also destabilize and reverses direction. Magnetic north becoming south, and south becoming north. Though this happens maybe ever 35,000 to 150,000 years without an established time frame or pattern. Despite this multi-thousand year cycling event there are localized anomalies I've seen in the last 200 years where for a small region the magnetic declination is briefly almost 180 degrees opposite. More often I've seen 45 to 80 degrees. Again these are brief shifting events in the overall history. Of note, It is very frustrating as a novice to better comprehend our poles than the "professionals". http://www.youtube.com/watch?v=DZFykyBigiU&feature=related Skip to 5:55 and watch. I saw this 2004 Nova movie called "Magnetic Storm". http://www.pbs.org/wgbh/nova/transcripts/3016_magnetic.html Where they imagine a Van Allen perpetual engine from the liquid core? The formula's and experiments are proof they aren't even considering non-ferrous Induction. I believe the Sun actively powers or generates our magnetic field. Through non-ferrous Induction it heats our iron/ferrous core. By my guess, it is during a prolonged solar max with high geothermal activity is most likely when our poles reverse. Also, http://science.nasa.gov/headlines/y2008/30oct_ftes.htm these Flux Transfer Events are similar to atmosphere free lightening strikes from the sun to the earth. The electrical arc (Flux event) transfers voltage like a wire. The flow of electrons forms a perpendicular magnetic field ("portal") just like electricity does in a wire. The close to 8 minute gap/interval is the time it takes for a stream of fresh charged particles to reach the earth and again form an arc/flux event.
Reply | Report Abuse | Link to thisTo be honest there is stronger evidence for sunspot/flare activity as being the source of temperature spikes, than for man made "global warming". Almost all evidence of global warming, that the media will often trumpet, comes back to be erroneous math, data, or fact collecting that the media never later reports. I 100% believe human can and do damage the earth's environment. However man made "global warming" is something of a stretch.
Reply | Report Abuse | Link to thisWhat if scientists took a look at the magnetic poles on other planets or even the sun by using their technology and what about Jupiters great storm...does that have anything to do with magnetism? What if this planet is headed in the same direction as Jupiter and the Sun?
Reply | Report Abuse | Link to thisThe Sun's flux in energy output is a small fraction of the heating effects of greenhouse gasses, and humans have increased CO2 by 38%, mostly since WWII when per capita energy use was 3 times less than it is now.
Reply | Report Abuse | Link to thisHuman fossil fuel use puts over 4 times more CO2 in the air than 1500 times the output of the world's worst volcano: Kilauea.
Thankfully, sulfur emissions from volcanoes and human coal burning cause global cooling. Thanks to the US's reduction in sulfur emissions in the 1970's, we began to experience global warming. Prior to that we were having global cooling, and the polar caps were maximized.
Now, with China building a new coal power plant each week, and thanks to 3 massive volcanic eruptions in the last 18 months, we'll have lot's of global cooling headed our way.
Jupiter's red spot is due to heat, as are the molten lobes of magma in Earth's mantle that form so called "mantle plumes", that one scientist proved caused Earth's magnetic fields.
Reply | Report Abuse | Link to thisThe Sun's magnetic field and Jupiter's magnetic field are not powerful enough to create such heat. Earth's heat is assumed to come from radioactive decay, otherwise Earth's core would have frozen billions of years ago. Our planet would be as dead as Mars and Venus if it weren't for our molten interior.
Lighting from the Sun? Well, of course! It's a constant! It's what causes the northern and southern lights. And it's more than just electrons, like in Earthly lighting. Solar radiation includes protons, neutrons, neutrinos, x-rays, uV, radio, etc. Streaming electrons are just a part of what makes the Van Allen belt so dangerous to astronauts.
Reply | Report Abuse | Link to thisBut all the solar flares combined won't power Earth's core. Imaginitively speaking, maybe electron flow could be flipped by a really BIG solar flare. But, again, the energy in solar flares is too small to compare to the heat in the Earth's core, which is what makes our magnetic field.
The Sun's magnetic field is almost as big as the orbits of the outer planets, but it won' move your compass needle, let alone power the Earrh's core.
Streaming particles from the sun bend and snap the Earth's magnetic field, but big solar flares aren't known to move the magnetic poles. Canadian power outages and satellite damage, however, are known effects.
Note: There isn't an 8 minute delay for these particles. If that were true, they would be traveling the speed of light. Electrons, protons and neutrons only travel fractions of the speed of light. That's why space weather satellites work so well. Photons travel the speed of light, and arrive hours or days ahead of the other particles.
If the Sun's magnetic field were strong
Oooops. I meant to type "lightning from the sun" and "Earthly lightning". This smart, yet stupid, iPod spell checker works on the fly.
Reply | Report Abuse | Link to thisThink about it. If solar cycles caused global warming, then we would have global warming every 5.5 years, followed by global cooling 5.5 years after that, then the cycle repeats.
Reply | Report Abuse | Link to thisEvery billion years the sun gets 10% hotter, but that's not an issue when we are talking about the 1940's through the 1970's having global cooling due to sulfur emissions from US coal plants, followed by 30 years of global warming, thanks to the fact we phased out most sulfur emissions by the end of the 1970's, yet increased our CO2 emissions gradually over the decades.
How does the 11 year solar cycle (5.5 warming, and 5.5 cooling) create a 70 year cycle (40 cooling, 30 warming)?
In the looooong run, we need to decrease CO2 emissions to ZERO, as the sun gets 1% hotter every 100,00 years. But, that's a long term goal. For now, we need to reduce CO2 emissions by the amount we increased it by using fossil fuels.
And don't forget deforestation! Continental wide clear cutting of forests, slash and burn, to make way for farms is also at fault.
Do you honestly think that a few tons of cows can fart enough methane to cause as much global warming as clear cutting thousands of tons of trees, and burning them? Tress remove cabon from the air, thousands of tons of it. Burning the trees puts its all back.
Good thing the tree line is moving north as the Earth warms.
Trees store water as well, preventing flood and draught. In that way the moving tree line will slow ocean level rise a bit.
However, I'm not sure it can compete with Brazil's slash and burn policies.
We'll see how it turns out. Whether the Earth warms or cools, it will be sad.
Yes, trees prevent draught beer. Darn these spell checkers.
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