Is Earth's magnetic field really a magnetic dipole field? Why does a global compass needle not flip 180° when travelling to the other hemisphere?
Is Earth's magnetic field really a magnetic dipole field? Why does a global compass needle not flip 180° when travelling to the other hemisphere?Why on earth should it?If you take a straight bar magnet, and draw a compass along its body, lengthwise, from pole to pole, does the needle flip when you cross the middle? No, it doesn’t even vary if you draw it down the centerline.At the North Pole, the South Pole of the needle (marked, usually, in Red, sometimes even with a big N on it, but it has to be a south pole to be attracted to the North Pole of the magnet) remains pointed to the bar magnet’s North, and the needle’s north pole is attracted to the bar magnet’s South pole.As the compass moves from north to south pole of the bar magnet, these attractions do not change with movement of the magnet. In fact, the magnetic lines of force (which are imaginary, but represent continuous points on the magnetic’s field) are smoothest around the center of the bar magnet.Likewise, the Earth. Everywhere on Earth, the needles of magnets alignt so the North pole of the needle’s magnetic field points to the South Pole of the Earth, and the South Pole (marked North because that’s the way it points) the North Pole of the Earth. This will not change until the magnetic field of the Earth changes, which some Scientists hypothesize can and will happen. That gets into hypothetical models of what causes the Earth’s magnetic field, but that is beyond the scope of the question. It is unlikely that the field of a compass needle or of the Earth will reach a state of instability where the direction of the needle will ratchet from the current state when it is north of the equator to the opposite state just because you have moved the compass south of the equator.
What causes the Earth to exert a magnetic force?
There are two common ways to make something magnetic. They are both accomplished by causing the electrons in an object, usually iron to align. The first way to do this is to take a magnet and slide it repeatedly from one end of a piece of iron to the other. This will cause the electrons to align and will give the piece of iron magnetic properties. The second is to move that piece of iron back and forth through a electro magnetic field. Electro magnets do this by wrapping a piece of copper wire around an iron bar and running an AC current through the wire. Because AC current runs in both directions alternately it causes the iron to become magnetized. The earth acts like a giant magnet because it has an iron core surrounded by molten rock, surrounded by a solid mantle (crust). Because the earth rotates at a high velocity, it spinns at a different rate than its core does. This causes the iron core to move alternately through the variouse natural EM (electro magnetic) fields effecting the earths crust. This causes a magnetic field around the planet. As with all magnets, they have a positive and a negative end. Because the earth spins in a east west direction the field lines converge at the poles.
The Earths magnetic force?
Some facts; without an essay to accompany them. Polar reversals occur every few hundred thousand years. This is documented in the seafloors (with a 180 million years record) where magnetite in basalt aligns itself to the current field. Polar reversals take a few tens of thousands of years to complete. When a polar reversal is taking place, the main dipoles are replaced by secondary dipoles located at places other than near the rotational axis. So don't sweat the small stuff, it isn't going to affect you, nor your children, nor your grandchildren, nor your great-grandchildren, nor your ...
Why is Earth's magnetic field important?
Without it life as we know it would not exist. Without earths magnetic field charged particles from the sun (solar wind) would strip away our atmosphere slowly. What wasn't immediately stripped away would become ionized, oxygen molecules and others stripped of their electrons and no longer breathable. The Suns radiation would increase dramatically and basically fry any life that survived the solar wind onslaught.Earths magnetic field is of the utmost importance, at least to life.
How is the magnetic field of Earth formed?
If the core of the earth was really a melted iron ore comperessed at high temperature beyound the Curie level magnetism would not be supported. Therefore the core of the earth cannot be the cause of magnetism since at high temperature, magnetic field cannot exist. Magnetism is caused by near light speed motion of particle in a material latice. Such occurs in atoms by the electron spin which is close to the velocity of light. Water which is a fluid covers our planet as a moving one. The motion of the current of the seas and oceans is the major cause of magnetic induction intensity. If you apply the Right hand rule to the motion ,the location of the earth's magnetic poles can be identified.
How does the Earth's core affect magnetic field?
Our planet’s magnetic field is believed to be generated deep down in the Earth’s core.Nobody has ever taken the mythical journey to the centre of the Earth, but by studying the way shockwaves from earthquakes travel through the planet, physicists have been able to work out its likely structure.Right at the heart of the Earth is a solid inner core, two thirds of the size of the Moon and composed primarily of iron. At a hellish 5,700°C, this iron is as hot as the Sun’s surface, but the crushing pressure caused by gravity prevents it from becoming liquid.Surrounding this is the outer core, a 2,000 km thick layer of iron, nickel, and small quantities of other metals. Lower pressure than the inner core means the metal here is fluid.Differences in temperature, pressure and composition within the outer core cause convection currents in the molten metal as cool, dense matter sinks whilst warm, less dense matter rises. The Coriolis force, resulting from the Earth’s spin, also causes swirling whirlpools.This flow of liquid iron generates electric currents, which in turn produce magnetic fields. Charged metals passing through these fields go on to create electric currents of their own, and so the cycle continues. This self-sustaining loop is known as the geodynamo.The spiralling caused by the Coriolis force means that separate magnetic fields created are roughly aligned in the same direction, their combined effect adding up to produce one vast magnetic field engulfing the planet.
Earth's magnetic field? Please Help!?
the sphere is reminiscent of that of a bar magnet, yet this similarity is superficial. The magnetic field of a bar magnet, or the different form of everlasting magnet, is created with assistance from the coordinated spins of electrons and nuclei interior iron atoms. The Earth's center, even if, is hotter than 1043 ok, the Curie aspect temperature at which the orientations of spins interior iron develop into randomized. Such randomization motives the substance to lose its magnetic field. for this reason the Earth's magnetic field is led to no longer with assistance from magnetized iron deposits, yet as a rule with assistance from electric powered currents in the liquid outer center (because it spins, electrons have a tendency to stay behind, accordingly generating a small present day). yet another function that distinguishes the Earth magnetically from a bar magnet is its magnetosphere. At tremendous distances from the planet, this dominates the exterior magnetic field. electric powered currents brought on in the ionosphere also generate magnetic fields. this kind of field is continuously generated close to the position the ambience is closest to the solar, causing daily adjustments that could deflect floor magnetic fields with assistance from as a lot as one degree.
What creates Earth's magnetic field?
The leading hypothesis is that the earth’s spinning core causes the Earth's magnetic field, but scientists are unsure about the exact mechanism by which it is created. Iron is the primary constituent of the Earth’s core, and it is able to spin because of its layered construction.No one has ever drilled or tunneled into the core to observe its function personally, so scientists must use mathematical models to understand planet formation. Scientists believe that the core has two distinct layers. There is a solid inner core and a liquid outer core. Both components exist at very high temperatures and are exposed to very high pressures. This causes the materials to behave differently than they would at the surface. Because the inner core is solid and has a greater density, it resists spinning as the Earth does. Instead, it remains relatively stationary while the molten iron surrounding the inner core spins with the Earth. Additionally, convection currents arising from the super-hot temperatures contribute to the liquid’s spinning motion. As the molten iron spins around the solid, crystalized iron inside the inner core, it generates a relatively weak earth magnetic field. This magnetic field helps to protect the Earth from dangerous types of radiation, and it helps make life possible on the planet.
Is it possible to repel against the Earth's magnetic field?
In electric motors it may appear that you are using a current to repel a uniform magnetic field, but in fact the force is at right angles to both the current AND the field (Faraday's left hand rule). Also, any current needs a return loop to make a circuit back to your DC battery or no charge will flow. This return loop goes back on the other side of the spindle to double the torque and keep the coil spinning provided you switch the current for the upside-down phase (commutator). The solar winds are static electric charges (ions), not currents in circuits, but they can be steered around by the Earth's magnetic field, not attracted or repelled by it, but spiraling around in the magnetosphere (Van Allen belts) until the thin air slows them down and they fall to Earth glowing in huge circular curtains centered on magnetic axis but thousands of miles from the actual magnetic poles. When you see superconductors maintaining their distance around tracks of permanent magnets, they do so by having eddies of current induced in them by movement through non-uniform magnetic fields. The Earth has a very uniform (and weak) field indeed relative to any coil you could build, but the reason it has never been done is that it would at worst flip if it were not spinning, and at worst fall if were not on the ground already. I meant to say 'worst' twice because it would neither hover nor repel. So we're stuck on Earth with wheels, wings and chemical rockets for a while, sorry!