From where does the energy  of the core rotating semi-liquid core come from, creating the earth magnetic field
413981
My last geology lessons (1983) suggested nuclear decay as the source for the heat.  The sheer weight of a column of 'earth' adds heat by compression.
273548
The Earth has a magnetic field very much like that of a bar magnet, directed from the geographic South pole to geographic North pole. Charged particles streaming outward from the Sun arrive in the Earth's vicinity. Collisions in the Earth's vicinity slow them down and they subsequently get trapped in spiral paths around the planet's magnetic field lines. A point of note is that the field lines become more dense as they approach a pole. As the lines become more dense the charged particles' path becomes flatter and eventually turns back on itself. A particle spiraling along the field lines from the South pole to the North Pole turns around at the North Pole spiraling back and heading southward. These are in effect magnetic mirrors. Particles trapped in this way accumulate in regions called the Van Allen Belts. There exists two such belts: one containing protons at a height of about 3,000 km and the other containing electrons at about 15,000 km. \n\nOne of the consequences of the belts is the aurora borealis and aurora austrealis. This occurs whenever the charged particles enter the atmosphere and excite the atoms in the air creating the colors you see. These are noticeable near the poles where the magnetic field lines dip toward the Earth's surface, carrying the Van Allen belts with them.\n\n---\nTypically the aurora appears either as a diffuse glow or as "curtains" that approximately extend in the east-west direction. At some times, they form "quiet arcs," at others ("active aurora") they evolve and change constantly. Each curtain consists of many parallel rays, each lined up with the local direction of the magnetic field lines, suggesting that aurora is shaped by the Earth's magnetic field, Indeed, satellites show auroral electrons to be guided by magnetic field lines, spiraling around them while moving earthwards.\n\nThe curtains often show folds called "striations." When the field line guiding a bright auroral patch leads to a point directly above the observer, the aurora may appear as a "corona" of diverging rays, an effect of perspective.
955371
The earth has an electromagnetic field that is generated by the earth's core.  The core is a ball of hot liquid iron and nickel spinning around, and the spinning of the metal generates the magnetic field. \nIt surrounds the earth, connecting to the earth at the north and south poles.\nIs that what you mean by "themagenet in earth not found in space?"\nIf that's not what you mean, perhaps you need to reword your question into more understandable English.
1173935
Magnetic field has to do with the polarize charge of material, such as Iron.  \n\nIt is believed there is significant Iron near the center of the earth and yes rotation will cause the charges to align and thus create a magnetic field.  This is called the "Dynamo Theory".\n\nJUST BEING IRON DOES NOT MAKE THINGS MAGNETIC.\n\n"Previous theorists have assumed that the entire Core (or the Inner and/or Outer Core) rotates as a single flowing object within the Earth. If that were the case, then all of the charged (ionized) Iron material  would follow a relatively circular path around a single axis that we could call the Magnetic Axis. Basic Physics tells us that when electrical charges follow a closed (relatively) circular path (which is effectively a current), a magnetic field is always created as a result. The measurable evidence of this scenario would be a simple "dipole" magnetic field, with a single North Pole and a single South Pole, geographically exactly opposite each other on the surface of the Earth."\n\nSo if this theory where correct the Earth stopping it's rotation would in allow the magnetic field to fad.  But there are major problems with the theory.  For example it is known that the magnetic poles have flipped (Switched places) several time in Earths past.  Will if we have magnetic poles because of the earth's rotation to switch poles we'd need to reverse the cores rotation.  This would be an ungodly amount of energy.  There is nothing known that would do this once let alone a number of times.  And even if something could do it, we should have seen signs of the massive damage that would have resulted with these forces in play, like the Earth falling apart.   But in fact the poles shifting seems to be a pretty peaceful process on a planetary scale. \n\nAnd that is only one problem with the theory.  This is actually a very, very complex subject and there really is no way to know what effect the Earth stopping would have on the magnetic fields.  But I have attached a link to a very good article on the subject and it's pretty easy reading (Keeps the scientific jargon down and uses layman terms.)\n\nOthers are correct tough in what holds us to the Earth is gravity, not magnetics.  So it's the Mass (How big and dense it is) that keeps us here.  And rotation actually wants to make thing's fly away from it.  So we stay because the Earths gravity overcomes the acceleration.  So the acceleration of 1000mph is actually always enacting upon us, making us want to fly off the planet.  So stopping the Earth will not make us fly off as others have posted.\n\nThink of the spinning rids at the fairs and theme parks.  When you spin you are thrown away from the axis, the best example is the cylinder you go in and stand up against the wall.  When it spins your back is pushed against the wall, even as it turns so you are now spinning vertically like a tired, instead of horizontal like a top.  But when they stop the ride you don't go flying out.  That's because the wall holds you in and your move with the ride.  Well gravity acts like the wall and you move with the earth.\n\nYou would go flying of the earth if it continued to rotate and the gravity field somehow disappeared.
177385
It's incredible how many crazy answers are given on this page. \nThe Earth's magnetic field is originated by the convection of molten iron and nickel within the outer planetary core.\nSo, the answer to your question is that the only way to switch off the Earth's magnetic field would be to freeze all that liquid metal. This will happen naturally by the way, but in some billion years.\nAnd tell us, why are you asking this?
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
1098440
In North pole of Earth there is South pole of Earth's magnet and in the South pole of Earth there is North pole of Earth's magnet.
925593
Don't pay any attention to the girl who said, "So we won't float away." The earth's magnetic field has nothing to do with holding us to the earth. What seems to be happening, and this is still in the theory stage, is this. The solid inner core which is almost entirely iron and the liquid outer core which is probably composed mainly of a nickel-iron alloy are rotating at different speeds and because of the turbulence in the outer core they act together as a giant electric generator (dynamo) to produce an electric current. This in turn produces a magnetic field in the same way as an electric current passing through a coil forms an electromagnet. In other words the earth is a giant electromagnet which produces a field that can be measured far into space.
86122
I was taught in school that it is due to radioactive decay of elements in the core.  That is pure bullcrap.  If it were true, every time a volcano exploded, there would be radioactive toxins spread out across the world.  Others say gravity pushing on the substances create heat and liquification of earth.  This may be somewhat true.  If you put a piece of solid ice in a chamber and put extreme pressure on it, it turns to liquid.  There must be some other source of internal heat generation though.  I have never found a satisfactory answer to date.  I really don't think anyone knows, just like gravity is still a big mystery.
911083
The references are a good place to start learning about the earth's magnetic field.  The field on earth's surface is affected by local geologic conditions.  As your altitude increases, the earth's magnetic field looks like the field of a bar magnet.  It will cause rotation in a bar magnet that's free to rotate.  That's how a compass works.  The calculations get complex.  Try looking at a textbook on magnetism.  You'll probably see it worked out as an example.  The force in the form of a torque will be a function of the angle between the bar's magnetic axis and the background magnetic field.
757349
HI.  Great questions.  just realised i only got 2 points for answering.  anyway.  Weird magnets aren't they.  they always have a north and a south pole.  Almost like a mini Earth!  at the centre of the earth matter is so supper heated that it almost, but not quite, turns into energy. This raw force changes into a mix of matter and energy, producing and expelling a strong field of power.   When volcanoes were very active in earths early years, quite frequently this strange mix spewed into our atmoshere and solidified quickly.  magnetism was trapped during this process and magnets were born.  strange but very true.  I L U J L.
49283
The heat is radiated from the core of the Earth - from the heat buildup from when the Earth was forming - the conversion of gravitational energy to heat.  It is cooler now than when the planets were forming, but it's still pretty dang hot at the core, and that's the heat that warms up the asthenosphere.
84285
Of course, the inner core is solid. It is the outer core that is fluid. \n\nNo one really knows what is producing heat in the inner core, and in what proportions:\n\n1. radioactive decay\n2. tidal forces heating, due to gravity gradient of moon, sun etc graviational field \n3. exothermic reactions\n4. gravitational energy release as denser materials settle down into the middle\n5. insulation (some of the heat is still primoridial)\n6. frictional forces from movement of materials in the earth\n\nand so on. This is obviously a fairly complicated nonlinear system, and we do not understand all the physics involved.
773087
None of the answers given so far can be right.  The Earth doesn't spin bolt-upright, the rotational axis wobbles over time (precession).  Both poles alternately spend 6 months of the year in continuous sunlight with little or no darkness, and then 6 months in almost perpetual darkness, so it cannot be just due to the amount of sunlight available.  \nI seem to remember reading an explanation for this that relates to the Earth's magnetic field channelling solar radiation away from the polar regions toward the equator.  Presumably then the poles are colder because the magnetic poles happen to be relatively close to the rotational poles and the radiation is being channelled away from these areas ?
24692
The best answer from the above choices: \nSlow moving convection currents within the molten aesthenosphere supply new material to the spreading centers in the earth's ocean floors and other places. These currents are thought to provide force to cause the motion of the oceanic plates, either directly, or indirectly through the mid ocean ridge building process. \n\nSubduction is only one part of the process of plate tectonics, that does provide some driving force by pulling the subducting plate downward. \n\nGravity has a role as well, as without gravity, the mid-ocean ridges would not have the weight to provide force with which to push the plates apart at the spreading centers, and the subducting plates would not have the force to pull plates. \n\nThe earth's magnetic field may have the least to do with plate tectonics, possibly no role at all.
587439
According to current thinking, there is not a reversal of rotation of the core. Rather, pole reversal is a much more complex phenomenon driven by convective flow in the outer core (the molten part) and Coriolis effect. The references below will give you an overview. According to ref. 1, the outer core is "seething, swirling, turbulent". Reversals take a few thousand years to complete, and during the reversal process the magnetic field looks like a fright wig. Currently the field is about twice as strong as normal, and is decreasing at about 1% per decade. Ref. 2 points out that although rotation alone (like that of a solid body) cannot produce dynamo currents, "disordered convection patterns can indeed produce an average dynamo field". Ref. 3 says there are many failed "attempts" at reversal before one does occur, "which is probably the reason why the times between reversals of the Earth's field are long and randomly distributed".
484046
Two main sources.  The first is that when the earth formed, it was very hot. The earth formed from a cloud of gas and dust, and then gained size from larger asteroids crashing into it for millions of years.  This left the early earth as a ball of lava. Because the earth is so large, it cools very slowly.\n\nSince the earth cooled from the outsize in, it eventually formed a crust, which insulates the inside even more, and slows down the cooling process. A good portion of the heat inside the earth is left over from its creation, about 4.5 billion years ago.\n\nThe other source of heat is the decay of radioactive elements inside the earth.  In the liquid early earth, the heaviest elements would have sunk to the middle. The earth's core is believed to be made mostly of iron, but there are traces of uranium and radioactive isotopes of  thorium, and potassium.