Ice giants have weird magnetic fields?

[Tom Mazanec]

Both Uranus and Neptune have wonky magnetic fields. Is there any theoretical reason for this type of planet to have such magnetic fields?

[korjik]

Generator of the magnetic field being far from the spin axis, maybe?

[EDG]

Both Uranus and Neptune have wonky magnetic fields. Is there any theoretical reason for this type of planet to have such magnetic fields?

I thought it was because of their internal composition - they have no metallic hydrogen layer, and instead have a rock core with (probably) a rock-ice mix and a salty water ocean and then a relatively thin hydrogen/helium atmosphere.

Most of their field is probably generated in the saltwater ocean, with maybe a component of it generated in a liquid metallic core deep inside the rocky central part.

Am I misremembering, or isn't Ganymede's own magnetic field supposed to be a bit "wonky" too?

[korjik]

I thought it was because of their internal composition - they have no metallic hydrogen layer, and instead have a rock core with (probably) a rock-ice mix and a salty water ocean and then a relatively thin hydrogen/helium atmosphere.

Most of their field is probably generated in the saltwater ocean, with maybe a component of it generated in a liquid metallic core deep inside the rocky central part.

Am I misremembering, or isn't Ganymede's own magnetic field supposed to be a bit "wonky" too?

Which means it boils down to: Generator of the magnetic field is far from the rotational axis.

[EDG]

Which means it boils down to: Generator of the magnetic field is far from the rotational axis.

Actually it doesn't . Yes, the magnetic field generator is far from the centre of the planet, but it still should be a spherically symmetrical shell around the planet's core (and therefore around the rotational axis), and as such it should be generating the field equally everywhere in the shell, shouldn't it?

The "wonkiness" of the fields is usually shown as if it was a being generated by a dipole source that was closer to one part of the surface, not at the centre of the planet. My understanding is that this is just how it appears from the outside, but doesn't imply that it's actually being generated from a specific point (rather than a shell) that isn't at the centre of the planet.

[forrest noble]

Tom Mazanec,

(why do) ice giants have weird magnetic fields?

According to the standard model of planetary magnetism the source of magnetism is internal to the planet. If instead planetary magnetism is based upon the relative motion of moving liquids and gases such as the Earth and its continents and oceans, or Jupiter and the other planets relationship between one atmospheric layer and another -- or liquid and solid surfaces, then planetary magnetism would seem to me to be relatively simple and explainable by known data.

Ice giants have atmospheric, liquid and solid surfaces, the interactions between them because of planetary spin causes ionization which could explain electrical interactions as well as seeming magnetic orientations -- according to this speculation.

[tusenfem]

Tom Mazanec,



According to the standard model of planetary magnetism the source of magnetism is internal to the planet. If instead planetary magnetism is based upon the relative motion of moving liquids and gases such as the Earth and its continents and oceans, or Jupiter and the other planets relationship between one atmospheric layer and another -- or liquid and solid surfaces, then planetary magnetism would seem to me to be relatively simple and explainable by known data.

Ice giants have atmospheric, liquid and solid surfaces, the interactions between them because of planetary spin causes ionization which could explain electrical interactions as well as seeming magnetic orientations -- according to this speculation.

Forest Noble, you have been warned again and again NOT to place ATM views in Q&A or S&T. But apparently you don't understand the word NOT.

One infraction coming your way.

[korjik]

Actually it doesn't . Yes, the magnetic field generator is far from the centre of the planet, but it still should be a spherically symmetrical shell around the planet's core (and therefore around the rotational axis), and as such it should be generating the field equally everywhere in the shell, shouldn't it?

The "wonkiness" of the fields is usually shown as if it was a being generated by a dipole source that was closer to one part of the surface, not at the centre of the planet. My understanding is that this is just how it appears from the outside, but doesn't imply that it's actually being generated from a specific point (rather than a shell) that isn't at the centre of the planet.

It may be a spherically symmetric shell, but the currents the generate the field wouldnt be symmetric.

[ToSeek]

Forest Noble, you have been warned again and again NOT to place ATM views in Q&A or S&T. But apparently you don't understand the word NOT.

One infraction coming your way.

After a protest from Forrest Noble, I researched the issue and found that he does not have a history of putting his ATM views in Q&A or S&T (though he has occasionally in ATM threads other than his), so we would like to apologize for that inaccurate accusation. However, the post itself is still not reflective of the mainstream viewpoint, and therefore is not appropriate to this forum. The infraction stands.

[korjik]

Tom Mazanec,



According to the standard model of planetary magnetism the source of magnetism is internal to the planet. If instead planetary magnetism is based upon the relative motion of moving liquids and gases such as the Earth and its continents and oceans, or Jupiter and the other planets relationship between one atmospheric layer and another -- or liquid and solid surfaces, then planetary magnetism would seem to me to be relatively simple and explainable by known data.

Ice giants have atmospheric, liquid and solid surfaces, the interactions between them because of planetary spin causes ionization which could explain electrical interactions as well as seeming magnetic orientations -- according to this speculation.

Just in case anyone missed the point of the moderator and admin comments about this post, this is all completely wrong. If the Earth's magnetic field were caused by the oceans and atmosphere, it would be really obvious. There would be significant deviation from a dipole due to the configurations of ocean currents, and the deviations would be easily attributable to the ocean currents. Not only that, by I seem to remember that someone checked all this a couple hundred years ago. I will have to check that tho.

[Tom Mazanec]

Sorry for the bump, but from popsci:







Diamond oceans could explain why the magnetic fields of Uranus and Neptune appear tilted so far off their north-south axes, given that they could deflect or tilt the magnetic fields. Both planets may consist of up to 10 percent carbon, the elemental building block of diamond.

http://www.popsci.com/science/articl...une-and-uranus

It is so romantic that these fields could be explained by diamond oceans.

I hope I live long enough to see if an extrasolar Neptune has wonky magnetic fields (perhaps fron detecting aurorae?)