20 replies to this topic

[blarney]

Hi all, i'm new here and would like to pose a question in the hopes that someone here can answer it with some authority. We've all been taught  the core of our earth is molten iron and the rotation of this core creates our magnetic field. We also know that molten iron cannot generate a stable magnetic field. Do we have anything empirical vs theoretical which establishes absolutely our core being molten iron? This may have a simple answer, but so far a number of men with physics degrees have looked at me like I had an eye in the middle of my forehead and could give no authoritative answer. I trust very little further than the basics in the various disciplines to begin with, as so much of the research must be linear in order to maintain funding. I'd appreciate any input.  Thanks

[socrates.junior]

blarney, on 09 April 2012 - 10:37 PM, said:

Hi all, i'm new here and would like to pose a question in the hopes that someone here can answer it with some authority. We've all been taught  the core of our earth is molten iron and the rotation of this core creates our magnetic field. We also know that molten iron cannot generate a stable magnetic field. Do we have anything empirical vs theoretical which establishes absolutely our core being molten iron? This may have a simple answer, but so far a number of men with physics degrees have looked at me like I had an eye in the middle of my forehead and could give no authoritative answer. I trust very little further than the basics in the various disciplines to begin with, as so much of the research must be linear in order to maintain funding. I'd appreciate any input.  Thanks

That right there, that's your main problem. You're starting with a false premise. In addition, the empirical evidence for the outer core being molten iron comes from observation of the main components of planets (or meteorites) in our own solar system.

[blarney]

Wow, i'll have to check on this some more. I've always "thought" I've known that molten iron cannot maintain a magnetic field, I even remember being taught this. I know folks in the foundry business and they say the same thing as well as the afore mentioned degreed fellows. Thanks for the response

[sepulchrave]

Molten iron cannot maintain permanent magnetic moments, but it can maintain charge and/or magnetic currents.

The molten core does not act like a permanent bar magnet, but rather like a turbulent electromagnet.

(In some sense this is obvious; the magnetic field of the earth is not a pure dipole and the poles wander about chaotically over time.)

A group in 1995 managed to simulate a planetary magnetic field using a molten core and solid inner core (the solid inner core also had a field but it was an electromagnet as well, not a permanent magnet), and even managed to reproduce a pole reversal (see here).

This simulation doesn't constitute proof, of course, but it does support the current theory.

[blarney]

I just looked at the site below for some recent studies and the best it seems that has been done to replicate the dynamo effect uses a liquid sodium solution with ferro fins(non molten) to agitate. The phrase "commonly accepted" is also used as well as plasma as the driving force. From what I see this is still theoretical and is not concretely understood but is still being quantified. The plasma theory appeals to me for other "non linear" reasons.


http://physics.aps.org/articles/v5/40

Edited by blarney, 09 April 2012 - 11:19 PM.

[blarney]

sepulchrave, on 09 April 2012 - 11:11 PM, said:

Molten iron cannot maintain permanent magnetic moments, but it can maintain charge and/or magnetic currents.

The molten core does not act like a permanent bar magnet, but rather like a turbulent electromagnet.

(In some sense this is obvious; the magnetic field of the earth is not a pure dipole and the poles wander about chaotically over time.)

A group in 1995 managed to simulate a planetary magnetic field using a molten core and solid inner core (the solid inner core also had a field but it was an electromagnet as well, not a permanent magnet), and even managed to reproduce a pole reversal (see here).

This simulation doesn't constitute proof, of course, but it does support the current theory.

I guess Its the "solid inner core" that throws me. I hope I'm not being too much of a neophyte but how do we end up with a solid inner core and a molten outer? I may be beating a dead horse but thanks for your patience.

[socrates.junior]

The solid inner core comes from the incredible pressure that is present at the center of the Earth. The outer core isn't under the same type of pressure.

[orangepeaceful79]

Now wait just a dern tootin minute!  I read on the internet that the insides of the earth are hollow like a chocolate easter bunny - because thats where the illuminati all live and control everything.  Hang on a sec...damn tinfoil hat keeps slipping off.

But anyway - this seems like a much more likely scenario than all the stuff scientists have come up with.  lol

[questionmark]

blarney, on 09 April 2012 - 11:26 PM, said:

I guess Its the "solid inner core" that throws me. I hope I'm not being too much of a neophyte but how do we end up with a solid inner core and a molten outer? I may be beating a dead horse but thanks for your patience.

Pressure, the same reason why water boils at a lower temperature on top of a high mountain then it would at ocean level.

[BFB]

questionmark, on 10 April 2012 - 01:13 PM, said:

Pressure, the same reason why water boils at a lower temperature on top of a high mountain then it would at ocean level.

Although its correct pressure is responsible, it is nothing like you example.

The reason why water boils at higher altitudes is because of a reduction in the air pressure.

Lower air pressure, lower boiling point. Higher air pressure, higher boiling point.  

The reason why the inner core is solid is because HIGH pressure overcomes the effect of high temperature at that depth. Nothing to do with your exsample which is atmospheric science

Edited by BFB, 10 April 2012 - 02:17 PM.

[questionmark]

BFB, on 10 April 2012 - 02:14 PM, said:

Although its correct pressure is responsible, it is nothing like you example.

The reason why water boils at higher altitudes is because of a reduction in the air pressure.

Lower air pressure, lower boiling point. Higher air pressure, higher boiling point.  

The reason why the inner core is solid is because HIGH pressure overcomes the effect of high temperature at that depth. Nothing to do with your exsample which is atmospheric science

Which in the case of the water is exactly the same thing: It has to overcome less pressure (in this case atmospheric) to boil on top of a mountain.

Edit: There are no physic laws for water or iron, there is just one. The difference is the amount of pressure to overcome and the temperature to achieve. The rest works exactly the same way.

Edited by questionmark, 10 April 2012 - 02:45 PM.

[jules99]

questionmark, on 10 April 2012 - 01:13 PM, said:

Pressure, the same reason why water boils at a lower temperature on top of a high mountain then it would at ocean level.

The thing that throws me is how motion is translated from the solid inner core to the liquid outer core (whose motion is described as chaotic/turbulent) and then to the crust with such a small amount of lag. For a fluid coupling with chaotic/turbulence it seems too accurate a translation of movement (from outer core to crust) as the "solid inner core makes an extra revolution every 900 years or so,"

http://www.newscient...-the-crust.html

I understand that the Earths inner motions have had a while to settle into cycles/patterns, just wondering if magnetic field might also be assisting  crust/mantle rotation..

[questionmark]

jules99, on 10 April 2012 - 08:29 PM, said:

The thing that throws me is how motion is translated from the solid inner core to the liquid outer core (whose motion is described as chaotic/turbulent) and then to the crust with such a small amount of lag. For a fluid coupling with chaotic/turbulence it seems too accurate a translation of movement (from outer core to crust) as the "solid inner core makes an extra revolution every 900 years or so,"

http://www.newscient...-the-crust.html

I understand that the Earths inner motions have had a while to settle into cycles/patterns, just wondering if magnetic field might also be assisting  crust/mantle rotation..

OK, simple experiment: Go to the kitchen and get a cup of water. Now drop a small piece of paper into that water put the cup on a table and turn it slowly. You will see that the piece of paper rotates slower than the cup. That is called inertia. Same thing if the piece of paper would be solid iron and the water liquid iron.

Now, how could a magnetic field form there? If we have friction in on a dielectric (i.e. a bad conductor) we tend to get so called static electricity. if there is a good conductor short circuiting the dielectric (i.e. iron core) the energy discharges.

To see what happens when electricity discharges take a compass, a piece of wire and a battery. Place the compass on the wire and connect the wire (for a few seconds) and see what the compass needle does.

That model is pretty much oversimplified but could get you on the right track.

[blarney]

You guys are great. Thanks for your input. The reason I'm looking at this is a little off the wall. I'm looking at the theoretical possibility of the earth expanding not only in volume but mass as well over long periods of time. Some reasons I ponder this theory are....Dinosaurs the size of Bronto could not have lived under our present gravity just on the blood pressure issue alone. Giraffes have MASSIVE hearts just for their brains to get blood/oxygen.    Obvious (to many) fitting of the continents as if they were at one time joined.  Smaller mass/smaller gravity.    E=MC2 works in reverse.....great amounts of energy will create small amounts of matter(relatively speaking) My limited understanding allows plasma (as in at the core of a planet) to create matter.   This is the general direction......    Okay , make me look stupid now
Thanks

[blarney]

Also, i do realize this goes against the recent theories plate tectonics, continental drift......  But that doesn't mean its not fun to think about.