yes I agree iron and nickle are overwhelmingly the main core elements (Ni also has the next lowest binding energy next to Fe), uranium would only make one billionth % of the core but because it's so dense it would end up in the center.JeffreyW wrote:
the reason why I keep iron/nickel as the center elements because they:
1. Have the highest binding energy. (uranium's binding energy is lower, weaker)
The strength or magnetic properties play no part, after the H and He are blown away whats left is the heavier elements, the densest will migrate to the center. Even if iron was 'weak' it would migrate to the center because its dense, where else can it go? strength and weakness do not apply to molten metal.JeffreyW wrote:2. Are very strong even under high temps and pressures (iron/nickel alloys are what they use in turbofans, not titanium alloys) (uranium is weaker)
3. Are magnetic, meaning they will clump together if an electric current is passed through them. (uranium is not ferromagnetic)
I think this is the wrong way to look at it. Again I agree the core is Fe an Ni , the billionth of a % which is uranium will migrate to the very center and make a sphere only a kilometer or so diameter, then I would imagine a layer of gold( the next densest ) perhaps a km thick around that and so on with tungsten but all these are totally insignificant because of their tinny amounts,99.999999999999% of core is Fe and Ni.JeffreyW wrote: You can't have star evolution without the star first forming a core. Without a stable core, there is nothing to layer the other elements on top of!
The way I see it is when H and He are mostly gone there will be a molten ball of all the other elements which will tend to settle out according to their densities , the lighter ,or rather less dense ones like silicon, potassium ,oxygen, nitrogen near the surface to make up the crust .
I think it's misleading to think the earth has a 'stable core' like you're building a house, it's all molten, and when molten no element is more stable or strong than another. the whole thing is held together by the overwhelming force of gravity ,which is dominant at these dimensions.
But my main point was that nuclear physics , worked out with particle accelerators, and bubble chambers, gives the reason there is so much iron and nickle. I'm suggesting if we want to get a complete understanding of SM , we should not ignore relativity and particle physics.