Gravity and magnetism and supernovae...?

Clodhopper
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Gravity and magnetism and supernovae...?

Post by Clodhopper »

I was wondering what it was about iron which caused stars to go nova and wondered if magnetism was effectively locally concentrated gravity or part of gravity...?

...and also if the magnetic quality of iron was what caused stars to go nova when they create it by fusion?

I know these are probably really dumb questions, but it just strikes me as a heck of a coincidence that the only magnetic material in existence (I think?) is the one that causes stars to explode when they create it; and whether they become actual black holes or not, the star's "corpse" is made of superdense material possessing enormous gravity.
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Gravity and magnetism and supernovae...?

Post by spot »

Iron has the lowest nuclear binding energy of all the atoms, per nuclear particle. Smaller atoms want to fuse to create iron, larger ones want to split to create iron. So iron is just the final stage of all the fusion that's been going on, it's a symptom of getting to the end of the star's ability to burn, not the cause.

Ferro-magnetism is a consequence of solid crystal alignment, gaseous iron isn't magnetic.
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Bryn Mawr
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Gravity and magnetism and supernovae...?

Post by Bryn Mawr »

Clodhopper;1376469 wrote: I was wondering what it was about iron which caused stars to go nova and wondered if magnetism was effectively locally concentrated gravity...?

...and also if the magnetic quality of iron was what caused stars to go nova when they create it by fusion?

I know these are probably really dumb questions, but it just strikes me as a heck of a coincidence that the only magnetic material in existence (I think?) is the one that causes stars to explode when they create it; and whether they become actual black holes or not, the star's "corpse" is made of superdense material possessing enormous gravity.


Certainly doesn't feel right, the magnetic effect in iron is a function of the crystalline structure of the material holding the imbalanced electromagnetic forces aligned rather than randomly distributed (as I understand it) and can be present or absent according to the degree of alignment whereas gravity is a property of the mass of the object regardless of its structure.

?Magnets distort the electromagnetic field whereas gravity distorts space-time itself?

Stars that are large enough go nova because of the extreme change in the rate of energy generation during transition - at a point in their evolutionary cycle dependent on their mass the density of the core becomes such that the outward pressure of the energy generated by the falling fuel supply cannot stop the collapse due to gravity but the rate of collapse in itself generates so much energy (possibly also triggering the next level of fusion) so quickly that the core explodes.

Happily, the titch we call The Sun won't reach this stage, it will just balloon into a Red Giant before fading into obscurity.
Clodhopper
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Gravity and magnetism and supernovae...?

Post by Clodhopper »

spot: Okay. But I thought stars burned helium into hydrogen, helium into lithium, lithium to beryllium and so on up the periodic table until it turned manganese into iron, at which point the star has seconds before going nova because of something about iron. All elements heavier than iron are created by the incredible forces generated in the single moment of that nova, which is why they are rare, and rarer the heavier they get. Am I wrong about this?

You seem to be saying the process of fusion includes the splitting of these heavier elements down to iron? Isn't that fission?

And if ferro-magnetism is a consequence of solid crystal alignment, how come the earth's core, which is highly compressed liquid iron, is magnetic and a conductor? Is it not feasible that in the incredible forces generated in a star, gaseous iron, highly compressed, might not also be magnetic?

Sorry if I'm just talking bollocks. I know I'm way out of my depth here.
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Clodhopper
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Gravity and magnetism and supernovae...?

Post by Clodhopper »

It's a particular sort of nova I'm talking about. The most common one I think. Class A?

Bryn: Ok, so gravity is just mass, any old how, and the more mass the more gravity and more it affects spacetime (and I'm having lots of fun failing to get my head round spacetime. Bubbles is as close as I've got so far.:D). Magnetism is a property of specifically organised atoms in iron only.

But why?

And what would happen if you projected an electromagnetic field over the event horizon of a black hole?

I really ought to stop thinking about this now or I won't sleep for hours...
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Gravity and magnetism and supernovae...?

Post by spot »

I think the earth's (and a star's) magnetic core or field is a consequence of the movement of an electrical conductor, not ferro-magnetism. It's all electro-magnetism.

I think the build-up of iron in an end-phase star prior to going nova is a slow process, not a trigger. I think you'll find an increasing spectrograph signature for iron in stars long before they explode.

When I wrote "iron is just the final stage of all the fusion that's been going on" I didn't mention fission because there's been none in the star. As you say, heavier atoms are only created later on after which they can start fission, outside of stars.
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Gravity and magnetism and supernovae...?

Post by spot »

Clodhopper;1376496 wrote: Magnetism is a property of specifically organised atoms in iron only.
That's the bit to focus on. Electromagnetism is a different beast. And ferro-magnetism happens in other materials too, some of which have no iron content and are designed to be ferro-magnetic. Nickel and Cobalt are magnetic for example.
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Bryn Mawr
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Gravity and magnetism and supernovae...?

Post by Bryn Mawr »

Clodhopper;1376496 wrote: It's a particular sort of nova I'm talking about. The most common one I think. Class A?

Bryn: Ok, so gravity is just mass, any old how, and the more mass the more gravity and more it affects spacetime (and I'm having lots of fun failing to get my head round spacetime. Bubbles is as close as I've got so far.:D). Magnetism is a property of specifically organised atoms in iron only.

But why?

And what would happen if you projected an electromagnetic field over the event horizon of a black hole?

I really ought to stop thinking about this now or I won't sleep for hours...


Damn this word trap - one day I'll remember to copy my posts before I post them :-(

I'm going to bed - I'll re-type my reply tomorrow :-((
Clodhopper
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Gravity and magnetism and supernovae...?

Post by Clodhopper »

I think the build-up of iron in an end-phase star prior to going nova is a slow process, not a trigger. I think you'll find an increasing spectrograph signature for iron in stars long before they explode.


Sorry my fault. I'm just talking about a the commonest (I think) sort of supernova. Or perhaps I mean just nova? Not small stars like ours.



Blast. it's now getting late enough I can't think about this clearly enough. I'll come back to it tomorrow and see if I can pick up my train of thought.

Note to self: Introducing possibly ferromagnetic material into an electromagnetic field?
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Clodhopper
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Gravity and magnetism and supernovae...?

Post by Clodhopper »

And ferro-magnetism happens in other materials too, some of which have no iron content and are designed to be ferro-magnetic. Nickel and Cobalt are magnetic for example.


Are they indeed! And bang next to iron by atomic weight, though heavier. One wonders if magnetism is in some way a consequence of being in the centre of the periodic table?

But getting back to my original question, it would seem you are saying that ferromagnetism has nothing to do with a star going nova when it creates iron, assuming it's the right kind of star. Gravity and magnetism are functions of different qualities of matter and interact weakly if at all.

I still wonder if the ferromagnetic qualities of iron are involved in the process of novae in some way, but it's probably just the human propensity to see patterns, even where they don't exist.
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