Thot

They're in the shell surrounding the core, not the core itself. Sure they've been forced outwards. Actually, they don't even need to be near the core, as long as they do form a more or less closed shell. Correct, but without context you can't know whether or not they are actually violated. I've searched, but haven't found any yet. Which is not to say that there are none, perhaps you'd be able to dig something up. Rest is answered in the text, so I'll spare myself quoting from there - you've seen the result. You might have a point, though. €: What I have found is someone else's attempt at discussing the hypothesis. Haven't read much of it yet, though, so I can't say anything about the quality. Probably easier to read, though.

Radioactive decay in the shell surrounding the core and the helium. It is forced outwards by an increase in pressure, which is brought upon by the heat generated through radioactive decay. The shell surrounding it is solid, as is the core, so heating can only result in an increase of pressure. A simple model to illustrate: ---++*++---- - are the outer parts, + the shell in which the decay is happening and * are the inner parts. The - parts can give off heat into space, so the heat does not cause an increase of pressure there. Likewise with the outer + parts. The * parts, on the other hand, cannot, so the heat leads to an increase in pressure there. This continues until the pressure in * is large enough to force part of it outwards through +. As for the rest, how do you believe to be able to understand the context without having read it? It's not just 'exchange iron core with hydrogen'.

Ok, here goes. That bit is taken from the second article. You'll probably notice why I said to read everything first.

Which in turn would raise more questions, eventually leading to me quoting roughly half of the articles. Great.

Well, actually you do. And you're still oversimplifying, so I don't see a point in continuing this way, sorry. Which is not to say I believe to be right, it just seems we're not going to find out either way. €: Not that I wasn't also simplifying. The longer - and more physically correct - version is in the article. Just read that first if you want to continue, I'm not going to rephrase everything that's written there to post it here.

Pressure. Which is, again, why I said to read the articles first. Just postpone answering until after that, it'll make things easier. That is a question of quantity, not quality, though. Which version'd actually happen you'd have to calculate.

I'll answer one part, the others should be answered by the articles. More after that. The whole gravitational system which's center is at the core of the earth is brought forth through the interaction between the molecules. There's not actually a single point in the center that attracts everything, it's just that as a result of the gravitational force between everything in the system it behaves as if there was. Ok, so the effect of centrifugal force increases with the mass of the molecule. In other words, at the same spinning rate, hydrogen gets a smaller push than iron - for this reason, the hydrogen is kept in the center even though the gravitational force between the hydrogen molecules is smaller. The iron, on the other hand, gets a stronger push and is therefore forced towards the outside. There, it's concentration rises. Now let's compare. At first, you've got, say, 2 parts hydrogen and 1 part iron per area at each point in the system. The hydrogen is kept in place wherever it is by the gravitational force between itself and the iron, i.e. the centrifugal force is not great enough to push it outwards. The iron, on the other hand, is pushed outwards, as the gravitational force of it's neighbouring hydrogen molecules is not sufficient to keep it in place. After a while, you'll have an area on the outermost part of the system where there's no hydrogen at all, so instead of 2 parts hydrogen and 1 part iron you've now got 3 parts iron. Furthermore, the increased gravitational force between the molecules - increased because of the now greater atomar mass per area - also increases the density, which in turn increases the gravitational force. And so on, until the equilibrium for this system is reached. So, you've now got a big increase of gravitational force per area in the parts where iron accumulates - in other words, on the outer parts. The radius has not increased in the process, as in the beginning we already had hydrogen on the outer parts, so the maximum centrifugal force has not increased, as well. Of course, some of the iron - the part that was already near the outside in the beginning - would have been lost. But apart from that, the mass is kept together. In other words - regarding the part you added - you've got - in flat view - a circle of iron around a dot of hydrogen. The circle is kept together by itself, i.e. the gravitational force between the molecules it consists of. Not a gravitational center in the earth's core. The gravitational force is stronger on the outside/in the circle. Regarding the temperature, you're point is valid, but only applies to the outermost parts of the hydrogen core - after some time has passed, at least. The inner parts cool down over time by giving off heat towards the outer parts. €: You'd have a point regarding the centrifuge if the core already consisted of the heaviest molecules in the beginning. In that case, of course, the whole thing would either be kept together as it is or blown apart with increasing speed.

Stuff's at the bottom of the page. The articles are dubbed 'cookbook cosmology'. Ok. You've got two systems you need to consider here, one being the earth as a whole - which's radius is kept constant by the gravitational and centrifugal force -, the other are the particles in relation to each other. For the gravitational center, only the first system is relevant. For the centrifuge effect, you need to look at the latter. Say you've got a spinning mass with roughly evenly distributed amounts of - for the sake of easiness just - hydrogen and iron. The whole mass is kept together and over time shaped into a sphere by the gravitational force. The centrifugal force slowly pushes the iron towards the outside, where it's concentration therefore rises. After some time, the inside consists mostly of hydrogen and the outside of iron. Now, since iron molecules are much heavier than hydrogen ones, the gravitational force between the molecules in a given area rises with the concentration of iron. In flat view, you could imagine the iron as a chain around the hydrogen. This chain keeps itself together through the gravitational force. For this, a sufficient concentration of iron is necessary, hence the chain expands away from the center for as long as the concentration is reached through the centrifuge effect - in other words, until the chain gets strong enough. Once the necessary concentration is reached, you have an equilibrium. As the earth's spin decreases, the centrifuge effect decreases as well and slowly hydrogen on the outermost parts begins to permeate through the iron chain. Arti... ah well. Ok, suppose the whole mass is at first (quite) cold. You get heat from two sources here, radioactive decay and sunlight. The radioactive materials that we have here in relevant amounts are (mostly) quite heavy, for which reason they'll get pushed to outside by the centrifuge effect just like the iron. Sunlight only heats up the surface, as well. From there, let's jump to the point where the equilibrium is already established. The radioactive decay heats both the outer and inner parts. On heating, part of the hydrogen liquidi- and gasifies and the pressure rises until at one point hydrogen starts to permeate through the iron. To be more precise, it'll rupture a passage through it. The effusion of hot hydrogen causes both the pressure and the temperature to fall again, until the radioactive decay has again generated enough heat to trigger another effusion. This explains the origin of volcanoes, as well. They're simply 'iron' pushed outwards by the stream of gas. €: I am aware that it's quite possible for the hypothesis to be ****ed by actual mathematics, though. Whether or not it works with the given amounts of stuff - i.e. if the equilibrium would be reached at a point that matches what we have, or even if it would at all - I don't know.

Please read the articles, that's answered there. There's no point in me restating bit by bit what has already been written. That rigid bubble -is- gravity. You're thinking too static there. Neither the gravitational nor the centrifugal force are the same on all points on the radius.

Which is why I said to read the articles first. According to the hypothesis, the earth's core has a temperature below zero. Close to absolute zero, actually. It's quite possible for it to act as a centrifuge only inside the system. The gravitational force could keep the whole thing together, while the centrifugal effect would result in said shift on the inside. And the solids could only pass through the hydrogen once it is in gaseous form. The gravitational center (and therefore also the point with the highest pressure, as well as it's amount) is the same as long as the distribution on the circumference is, the radius does not matter.

Which temperatures? Rotation, for one. Think of the earth as a centrifuge and then consider that it most likely spun faster in earlier times as it slowed down over time to the speed it now has. As for the rest, I'll do some further reading. I suggest you do the same, though. Reading the articles I've linked to, that is.

I've come across an interesting hypothesis regarding the earth's composition, specifically that it's core does not consist of iron, but of hydrogen and is not hot, but cold. Unlike hypothesis like hollow earth, this one seems to fit with known facts like the earth's magnetic field (See http://en.wikipedia.org/wiki/Metallic_hydrogen). Sadly, I've only been able to find one author that has written specifically about the subject (he's called Neil B. Christianson). Does anyone know of other works regarding the subject than his? Some stuff that he has written about this hypothesis can be found at the bottom of http://www.cthisspace.com/ftl/features.html. He states that the heat coming from the inner parts of the earth could be explained with radioactivity alone, though whether this is accurate I don't know. According to http://en.wikipedia.org/wiki/Kola_Superdeep_Borehole drilling deep into the earth's crust seems to lead to the effusion of hydrogen, though I've read other explanations for it's origin. It'll be interesting to see what http://en.wikipedia.org/wiki/Chikyu_Hakken will find, as they're going still deeper. What do you think about this?