I was wondering why earth has a magnetic field and I thought it was interesting that the magnetic field tends to be oriented about the earth's axis of rotation. So why does the earth have a magnetic field? Could it have something to do with the extreme difference of velocities between the outer rotation and the inner rotation of the earth around it's axis? Could the earth's magnetic field be a way of re-balancing something? Isn't it true that things moving at faster speeds stretch out in the direction of movement and also the atoms run slower? Yet the earth is connected, on the atomic level, as one single object all the way through, despite these differences. Maybe the magnetic field is created from, and evident of, this disparity?
"The field is similar to that of a bar magnet. The Earth's magnetic field is mostly caused by electric currents in the liquid outer core. The Earth's core is hotter than 1043 K, the Curie point temperature above which the orientations of spins within iron become randomized. Such randomization causes the substance to lose its magnetization." The above is from Wikipedia.
Is the earth's magnetic field influenced by the sun's magnetic field? Do all the planets(which contain measurable magnetic fields) have their magnetic polarities oriented in roughly the same way? If the sun's polarity was to reverse, would the other planets soon follow?
The Earth has an outer core thought to be liquid iron. The liquid circulates in complex ways. Iron is magnetic, so the net motions of the liquid create a net magnetic field. You're thinking of relativity, maybe. The Earth doesn't rotate fast enough for relativistic effects to be significant. Most of the Earth is liquid, which flows around inside the Earth. All the land and the oceans float on a sea of liquid magma. Not really. The shape of the Earth's magnetic field is, however, distorted to a large extent by charged particles that are constantly flowing out from the Sun past the Earth. No. And even the Earth's polarity flips ever few hundred thousand years, on average. There's no reason why they would.
i understand this to be true.. but how does the statement of heating a magnet up will cause it to loose its magnetism and hot magma flow causing earths magnetic field, conflict? what holds the land masses in their positions? why isn't the crust of the earth constantly shifting in response to those flows? which is why mars will never be practical to colonize..(mars doesn't have magnetic field to protect it) wanted to post other pics for response to you but there would be too many so i will just do this one.. Please Register or Log in to view the hidden image! "The BBC has an article on the release of the first worldwide map of magnetic anomalies, deviations in the earth’s magnetic field due to effects from magnetized crustal rocks. Nice views of the magnetic striping on either side of the Mid-Atlantic Ridge resulting from ocean-floor spreading (the driver of continental drift) and prehistoric reverses in the direction of the earth’s magnetic field:" map of magnetic reversals..
A bar magnet is solid. The earth's outer core is liquid. When you hit a bar magnet the magnet dipoles inside it flip around to random orientations, wrecking the magnetic field. On the other hand, the Earth's field is caused by convection (flow) of the liquid rather than alignment of dipoles. The land masses aren't held in position. They float on tectonic plates. It is.
the flow of the liquid does not line up the electrons? how does convection create a magnetic field? how much do they move? (from a north/south perspective)
No. Liquid molecules tend to be quite free to move and rotate. I'm not certain about the details, actually. But any kind of moving charge creates a magnetic field, so atoms of iron flowing along can potentially create fields. You actually need some separate motion of the electrons and nucleii, I think, or else the fields from the moving positive charges would cancel out the fields from the negative charges. I'm not sure what you mean by "from a north/south perspective". Tectonic plates move at various rates depending on where they are, but from memory they tend to move only a few centimetres a year. Over hundreds of millions of years, that is enough to drift the continents around quite a bit.
could the electrons induce a charge into the iron particles? is the core magnetic? (would make sense if it is) does the core grow? (gravity attracting iron particles.) had enough yet? (used to piss teachers off by trying to get them to say 'I don't know'..Please Register or Log in to view the hidden image!) it makes sense to me if the crust is floating on magma, then the core would be spinning slightly faster than the crust,so i assume movement with the spin of the earth. i was trying to validate a hypothesis (correct term?) that there was a major crustal movement in our history is what caused the global flood stories, i suppose it would not need to be limited to a northern/southern movement.
Again, I'm not sure what you mean by that. All iron is magnetic. Whether the core has a net field or not, I'm not sure. The Earth is slowly cooling, so I guess the solid core is gradually growing as some of the molten iron around it solidifies. There's lots of things I don't know; I'm happy to admit that. I think its a bit more complicated than that, but I'd have to research the details. There are no global flood stories, really. There are plenty of stories of big floods, coming from different peoples in different regions of the world. To ancient peoples, a big flood might well have seemed to cover "the whole world", but no flood has ever really done that. There has always been land above sea level, even when the Earth has gone through very warm periods where the oceans were a lot higher than they are today.
maybe i don't either... i'm trying to get a picture in my head of whats going on.. i would bet that the core is magnetic (it would be induced if it was not) maybe the iron particles in the molten magma is magnifying(affecting)the cores magnetic field (dunno, just thinking..) what is the unit of measurement for magnetic fields (maxwells?) what does the earths field measure out to(as compared to a bar magnet)? if there is magnetism in the magma and iron..there should be a current..(although i would think it would be chaotic and unmeasurable).. it makes sense to me if that the gravity of the core, along with its magnetism, would attract iron particles to it. what else is in the magma? with magma being a liquid, and other particles in magma i can picture a flow of iron particles flowing into the core..wait..if the cores magnetic field is attracting the iron particles then that means they are getting magnetically induced, so they would have dipoles lined up in the direction of the attraction, although each particle is independent of each other they all (pry more correct to say 'most') would be aligned to the attractor, and this would amplify the cores magnetic field..correct? the phrase ' I Don't know' is the beginning of knowledge.. i'm a carpenter..i'll will leave the heavy lifting to those more qualified.. i have heard both arguments for sea fossils found on mountain tops,what i don't know is where those mountain tops are and how high they are..
i said magnify, but maybe it diminishes? i have probs wrapping my head around how the earths magnetic field can be so immense yet so weak..if it were strong we would not be able to pick up a iron bar, it would be stuck to the ground..so it has to be week enough to not attract magnetic materials, but it extends so far into space..confused.. also..james you have mentioned non magnetic materials.. with enough force even non-magnetic stuff can be affected by magnetism,see levitating frogs..don't know if this applies to your point..but here it is anyway..
Better: Iron is conductive. The net motion of the liquid creates a time-varying electric field, which in turn generates a magnetic field. The mechanism currently believed to be responsible for the Earth's magnetic field is described by hydromagnetic dynamo theory (scholarpedia article: http://www.scholarpedia.org/article/Hydromagnetic_dynamo_theory). This page, http://www.es.ucsc.edu/~glatz/geodynamo.html, describes the geodynamo. Four conditions are needed for a nonlinear dynamo such as that responsible for the Earth's magnetic field to exist: An existing magnetic field. Explaining the origin of the Earth's magnetic field at least 3.45 billion years ago is outside the scope of dynamo theory. An electrically conductive fluid. The Earth's outer core is mostly molten iron. Rotation. The core rotates more or less in synchrony with the Earth as a whole. An energy source to counteract losses due to electrical resistance. The energy source that sustains the dynamo is a combination of radioactive decay in the Earth's inner core, energy released by the growth of the Earth's inner core (heat of fusion), and selective freezing of material at the inner core / outer core boundary (the lighter stuff that doesn't freeze is buoyant).
I would agree & think James's statement that "iron is magnetic" in this context i.e. iron of the earth's core, is false. Surely the temperature there is well above the Curie temperature, even if there is some slight pressure effect on the Curie temperature. Earth has a magnetic field because of thermal gradients driving the magneto-hydro-dynamic effects, not because the core is mainly iron. If the core were a better electrical conductor and flows, prior field, etc. were all the same, I am almost sure, EARTH WOULD HAVE A SIGHTLY STRONGER MAGNETIC FIELD if the core were made of silver. I keep count of James's errors, but he makes them so seldom that I not sure, if this is number 4 or 5 now. I make errors much more frequently - a more than one per year rate and James' rate is less than that.
