Has the magnetic field of the Earth always been oriented the way it is now?
342702
No it hasn't. It's been this way since before Humans walked the earth or at the very least since some bright spark invented the compass. However, we know that the earths magnetic field has changed over time by looking at the direction of magnetism in a cross section of magnetic rock! The direction changes at different points in the cross section and the lower you go, the earlier in time it is.
934445
A molten core of super heated metal (believed to be Iron and Nickel) is spinning at the center of the earth faster than the exterior of the earth is rotating.\n\nCharged Particles create a magnetic field when they move.
212109
Apparently there is believed to be none now, but there may have been in the past.  Here is a quote from the link below:\n\nObservations of the magnetic fields on Mars by the Mars Global Surveyor spacecraft have revealed that parts of the planet's crust has been magnetized. This magnetization has been compared to alternating bands found on the ocean floors of Earth. One interesting theory, published in 1999 and reexamined in October 2005 in a publication by the same group, is that these bands could be evidence of the past operation of plate tectonics on Mars. However, this has yet to be proven or widely accepted and remains an area of active research.
126028
Currently, the earth's north magnetic pole moves about 40 kilometers per year.  The rate has varied considerably; it was only 10 km per year a century ago.
840444
The origin of the Earth's magnetic field is not completely understood, but is thought to be associated with electrical currents produced by the coupling of convective effects and rotation in the spinning liquid metallic outer core of iron and nickel. This mechanism is generally known as the dynamo effect. \n\nBecause of the rotating outer core,it produces an electric current, which in turn, produces a magnetic field that also interacts with the fluid motion to create a secondary magnetic field. Together, the two fields are stronger than the original and lie essentially along the axis of the Earth's rotation.
523133
Earth's magnetic field, among other things.
859047
The earth's magnetism is a result of the fact that the core of the earth is liquid; as the earth spins around this liquid center, it creates polarity.
593784
Someday it will be.  Earth reverses its magnetic poles periodically, so one day Antarctica will be to the north.
608387
The Earth's center contains a lot of molten iron; due to Earth's rotation, it rotates too, thus generating a magnetic field. It's bit more complicated, but in a nut that's the explanation.
1020724
Based upon the study of lava formations in Hawaii, it has been deduced that the Earth's magnetic field reverses at intervals, ranging from tens of thousands to many millions of years, with an average interval of approximately 250,000 years. The last such event, called the Brunhes-Matuyama reversal, occurred some 780,000 years ago.\n\nThe mechanism responsible for geomagnetic reversals is not well understood. Some scientists have produced models for the core of the Earth wherein the magnetic field is only quasi-stable and the poles can spontaneously migrate from one orientation to the other over the course of a few hundred to a few thousand years. Other scientists propose that the geodynamo first turns itself off, either spontaneously or through some external action like a comet impact, and then restarts itself with the magnetic "North" pole pointing either North or South. External events are not likely to be routine causes of magnetic field reversals due to the lack of a correlation between the age of impact craters and the timing of reversals. Regardless of the cause, when magnetic "North" reappears in the opposite direction this is a reversal, whereas turning off and returning in the same direction is called a geomagnetic excursion.\n\nUsing a magnetic detector (a variant of a compass), scientists have measured the historical direction of the Earth's magnetic field, by studying the layered iron-rich lava rocks. This is possible as each layer has been found to maintain the original magnetic field at its time of cooling. They have found that the poles have shifted a number of times throughout the past.\n\nThe above is a quote from Wikpaedia and magnetic pole reversal is well documented in scientific literature. It still begs the question raised by one of the correspondents above as to why then there were not great extinctions as the magnetosphere would be disrupted and lethal cosmic radiation would harm all surface dwelling life.
346576
Nope. \nThere is some evidence that people can sense the magnetic field of the earth and tell which way magnetic north is. But as for true north no one can do that without knowing the magnetic variation for the location they are at.\nWell if you know the time of year and about where you are you could tell true north from the stars but that would be about the same as knowing the magnetic variation for your location.
400182
I love this type of science - this is the only science that I know _-- Earth Science!\n\nIn 1963, Fred Vine, Drummond Matthews, and others found that the crust surrounding the midocean ridges showed alternating bands -- each band magnetized with a polarity opposite the surrounding bands. They suggested that as new sea-floor crust was formed around the rift in the midocean ridge, it magnetized differently, depending upon the polarity of the planet at that time. This supported the theory that Harry Hess had put forth, that the ocean progressivley widens as new sea floor is created along a crack that follows the crest of midocean ridges.\n\nIn 1966, earth scientists first identified the Jaramillo Event, the wholesale reversal of Earth's magnetic fields some 900,000 years ago. This confirmed the theory that Earth's magnetic field had flip-flopped through the planet's life, and it made Matthews and Vine's 1963 finding quite clear. They realized that the pattern of reversals matched perfectly the magnetic profile they had compiled of the sea floor. This discovery, together with data from a 1964 research vessel, transformed the field of geology. It confirmed sea-floor spreading as hypothesized by Hess, and thus "continental drift," originally proposed by Alfred Wegener back in 1912. It convinced many that plate tectonics was the best theory to unify nearly all the previously accumulated, but disjoint geological data.
1112646
The pole in the north direction of earth is the south magnetic pole of earth's magnet.\n\nThe position of magnetic pole is changing but not the pole itself. If the pole cahnges then the magnetic needle in the compass will deflect in the opposite direction.
944389
I researched this as a geology student 20 years ago and has interested me since then.  By researching cores of basalt, they have a pretty good idea what the magnetic field does when it starts to shift but it is somewhat random and slow.  I remember that typically, before the switch in polarization, the poles starts to migrate in a spiral as it is doing now.  It has been an extra long time since the last switch so it is due.  I suspect that it is about to switch (within the next thousand years or so) but no one can say for certain in my opinion.  Apparently there is a period of time (100 years or so) when the field is next to zero in strength.  I saw a show on it recently that demonstrated they have learned a lot since I studied it in school.
452277
Earth's magnetic field constantly fluctuates to some degree (it's weakened by about 10% since the 19th Century), but the majority of geophysicists see no hard evidence that the field is about to reverse like it's done in the past.\n\nEven should it reverse, the whole cycle takes thousands of years, and still would have little effect on our electrical power systems. Nor would planes fall from the sky, although reliance on magnetic compasses would have to be adjusted.\n\nGod should be spelled B-I-G B-A-N-G\nPBrax@netscape.com
363234
Well, it seems like someone hacked into AskJeeves, because I became so curious about your question that I went to AskJeeves. \n\nAnyway, visit this page:\n\nhttp://www.askforkids.com/web?q=Why+does+Earth+move+on+a+tilted+axis%3F\n\nPerhaps it shall work on your computer. Whenever I click on the result, it visits the page temporarily and then suddenly goes to a different page, which seems to want to advertise, though it's under construction.\n\nGreat question!\n\nI personally believe that if the Earth did not use a tilted axis, it would not have electromagnetic fields across it. This would vary the different compositions of materials, and though I do not have very much knowledge about this, it probably would mean that humans could not survive, because humans use electromagnetic forces for various things.
317284
Well, the Earth's magnetic field has dropped to near zero many times in the past; whenever a magnetic reversal occurs, the magnetic field grows much weaker before it reverses polarity. It has been shown that the Earth went with only an extremely, extremely weak magnetic field for about 2000 years. Apparently, life was not too adversely affected by it; we still exist, and no extinction events coincided with the time frame. Therefore, the most we would have to worry about is the radiation we would recieve from the sun and space; an increase in skin cancers could be expected, though not much else.