Belief in Earth's Iron Core still puzzling

[CharlieO]

Let's see. I didn't claim Earth has a hydrogen core in this thread. Some people can sure jump to conclusions or should I say, make assumptions. All I asked was, "Does anyone know of a more plausible theory of how Earth developed a core containing such a enormous excess of iron?"

Eaarth's formation in an iron-rich ring of dust and gases is a new one for me. How very convenient. How equally unlikely, but a good attempt and perhaps even possible. At least someone may not be committed to dogmatic assumptions.

So many seem to think Earth is a totally unique situation. I, for one, perhaps the only one it seems, thinks Earth was formed by a process that is no different than that of many others, if not all others. Which is why I find the Grand Bombardment theory so stupid, when the gravitational attraction of the Sun and Jupiter is considered. Hard to believe some so-called scientists would even consider 'swarms' of iron-rich micro-planets attacking only Earth in a short (?) period of time and making it molten, while the swarms apparently ignored the Sun and Jupiter.

Apparently, the usual assumptions made in amother thread are still being vented, even though I stated I don't know if Earth has a hydrogen core and only asked where did all the iron come from. Puzzling to say the least, considering I was previously assured the basis for this forum is 'social' discussion.

Please answer the question, if you can, and save the condemnations for another thread, in which I can't find the time to participate due to my time consuming care-giver duties during the day.

Apparently, the fact that no one really knows for sure seems to have hit a nerve. At least I know I don't know everything. I only wanted to know if there were any other theories about Earth being formed with an enormous excess of iron which had some logical sense about them.

Well? Where did all the iron come from? Why does the Sun and Jupiter have so little? Simple questions from a simple old car mechanic.

Anyone remember the story of the Emperor's new clothes?

[stereologist]

Charlie your comments in this post are a bit weird. Not a flame, condemnation or whatever.

Eaarth's formation in an iron-rich ring of dust and gases is a new one for me. How very convenient. How equally unlikely, but a good attempt and perhaps even possible. At least someone may not be committed to dogmatic assumptions.

This paragraph for instance appears to be full of uncertainties on your part.

Which is why I find the Grand Bombardment theory so stupid, when the gravitational attraction of the Sun and Jupiter is considered. Hard to believe some so-called scientists would even consider 'swarms' of iron-rich micro-planets attacking only Earth in a short (?) period of time and making it molten, while the swarms apparently ignored the Sun and Jupiter.

Then you anthropomorphise the situation and ridicule a theory that you hint you don't understand.

Apparently, the usual assumptions made in amother thread are still being vented

Apparently, the fact that no one really knows for sure seems to have hit a nerve.

Next you suggest that you are being treated poorly. I've seen a lot of good information from some knowledgeable sources.

From the beginning you did say:

I don't know if Earth has an iron core or a hydrogen core, albeit the latter seems more likely to me;

So you sided with hydrogen in the original post and people went to some length to show that hydrogen doesn't work, but iron does.

Next your post reviews some material suggesting iron as the core. But you point out that iron is a small amount of the known mass of the universe. After you described a theory you came up with a few paragraphs why this theory does not make sense to you. Then you mention another theory and dismiss that as well.

The problem here is that step 1 was to address the claim that hydrogen was more likely the core of the earth. Now you want to go on to step 2 which is to gain a better understanding of theories about the formation of the earth.

[stereologist]

The universe is about 0.1% iron. What about our solar system?

The sun and other planets is about 333,000 times the mass of the earth. In addition there are asteroids and comets and whatever. If the solar system is about the same ratios as the universe, then our solar system contains 333 times as much iron as the weight of the earth. Take out the entire mass of Jupiter and that still leaves 15 times the mass of the earth in iron alone. There is plenty of iron around.

You mentioned an observation made by Hubble. When you spin a disc where does the heavy material end up? If the sun heats up what does the lighter material go?

What about the asteroid belt and the fact that comets are still seen. Does that conflict with your thought expressed here:

Which is why I find the Grand Bombardment theory so stupid, when the gravitational attraction of the Sun and Jupiter is considered. Hard to believe some so-called scientists would even consider 'swarms' of iron-rich micro-planets attacking only Earth in a short (?) period of time and making it molten, while the swarms apparently ignored the Sun and Jupiter.

[arkain101]

CharlieO is wondering. This is a good thing. Lets be kind or be gone.

He did ask some good questions, and I believe would learn about the answers for them.

1)What are the theories that describe the process for earth attaining an iron rich core, and evidence for them?

I don't believe Charlie has dismissed any existing theories as false. Although he has referred to some explanations as stupid, which is fine if that is how he wants to feel about it, but hopefully this is not how he responds to the feedback contributed on this forum.


I interpreted his intentions as being curious, based on the fact he is puzzled.

He provided suggestions based on his knowledge, allowing us to get insight into his thinking. And at the same time provided questions to help find information alternative to his thinking, so that he may be rid of this puzzled state.


Anyway, whether I agree or disagree on how people are treating this topic is besides the point. The puzzling thought of earth obtaining high amounts of iron in a rather low iron content universe. Surely some of the answers must offer up a bit of the fact that this particular solar system was quite rare, one in a million you might say. As for lucky? well that wouldnt be an appropiate word.. It would pose the question of lucky for whom or what, which is a bit off the topic.

I have not studied this subject at any great lengths, that is, the formation of planets, and more specifically our own local system. So this is interesting.

I probably would not have been inspired (anytime soon, lol) to study it if it wasn't for the questions Charlie has asked, so in that respect I thank him.

I see there have been some links provided, and I will be sure to check up on them.

[arkain101]

When you spin a disc where does the heavy material end up?

Well, I really don't know how to answer that off the top of my head, because I really don't know what it is asking.

As I understand in a gravitationally formed disk, the orbital region is not dependent on the mass. That is, objects can orbit at any region around a gravitational source.

What force is "spinning this disk"?

Unfortunately I don't follow you here.

[Turtle]

Anyway, we're just not going through all this again. The simple fact is that this earth-core-not-iron bit is all based in Fundamentalist Christian Creationism and at Hypog that doG don't hunt.

Originally Posted by CharlieO

12-07-2007 To ALL: If any want to expand their beliefs beyond the popular assumptions regarding Earth's core, there are books and articles by Neil B. Christainson and C. Warren Hunt and others which explain the probability of Earth having a hydrogen core in both greater detail and far better than I. ...

Amazon.com: Two Hundred Years Astray: Neil B....
Amazon.com: Two Hundred Years Astray: Neil B....

Neil B. Christianson book title: Two Hundred Years Astray: The Epistle To The Creationists

Will the staff be so kind as to move this thread to Silly Claims where it belongs?

[Pyrotex]

A few thoughts on CharlieO's other questions about origin of Earth's iron core.

There is, indeed, a LOT of iron in our Solar System. Aside from H, He, C, O, Cl, Ar, Si, Na, K, Mg, and possibly a few other elements, iron (Fe) is the most common element around. And it is the MOST COMMON "heavy" element by far. H,He, O, Cl and Ar are gases -- Na, K, and Mg are very light metals, and C and Si are light "transition" elements.

Iron is common in the universe because it is the lightest element that is ENDOTHERMIC under Fusion. That means, all other lighter elements can be fused with H or He and RELEASE energy. If you attempt to fuse Fe with H or He, it ABSORBS energy. All elements heavier than Fe are also Endothermic under Fusion. Why do we care? The lighter elements are created in the cores of ordinary stars as they age, until finally they produce iron. If the star is massive enough, the core will become denser and denser as the Fusion fuels become exhausted, and the pressure will force iron to fuse. This absorbs so much energy that the core collapses, triggering a supernova, which blasts all the outer shells of elements (including iron) out into the surrounding space. Look at a picture of the Crab Nebula.

This is where all the common elements come from. Including iron.

The innermost core of the supernova releases so much energy that the elements heavier than Fe are produced, but only in trace amounts. That's where gold comes from.

When a Sun like ours condenses from primordial gas and dust, there will almost always be a residual spin. As it condenses smaller, the spin increases until the star suffers instabilities at its equator. An equatorial ring of matter forms and cools. Compounds containing heavy metals, like iron, or the metals themselves, will be the first to become solids. We know this because a significant portion of meteorites that crash to Earth contain 95% pure iron/nickel alloy. (I have one.)

When the Sun-like star finally achieves full Fusion at its core, there is a "fusion-flash" that occurs while the star is achieving equilibrium. This flash heats up and drives off the equatorial ring. But selectively. Solids, being denser, will be slower to heat up, and harder to drive off. The proportion of iron, and indeed, of all solid compounds, many of which contain C and Si, will be highly increased in the region nearest the star, and the lighter stuff, especially H, He, and a portion of the C and Si, will be selectively driven further outward until it, too, can cool enough to form molecules, compounds and dust.

So, we have a plausible mechanism whereby the elements and compounds are separated by mass. Very much like a mass spectrometer in a laboratory. Only it's done by the fusion-flash, instead of with a magnetic field. Near the Sun, iron and its compounds can become a significant percentage of all matter -- say 10% to 20%. Far from the Sun, H and He remain the dominant components. In the region in between, you have iron making up only 1% or 2% of the matter and H and He still very significant.

This results in a relatively smooth transition of planet types. Iron core planets near the star, H/He gas giants far from the star. Transition planets in between.

How do the iron planets form? The secret is water. Water, in both liquid and solid forms, makes for an adequate "glue" to bind small dust particles together. Water in vapor form can absorb to the surfaces of particles, helping to cool the particles, and itself. As more and more particles clump, the average size of dust particles increases. This will occur mostly in a zone around the star where water can be in its liquid state, at least part of the time, under the right conditions -- like in the core of a clump of dust particles.

Particles and clumps smash into each other, and break up into finer dust. The finer dust reclumps eventually and smashes again. But this process slowly but surely evens out all the dust orbits, making them almost circular and all in the same plane. By then, some clumps have gotten large enough to hold together by their own gravity.

When a clump is large enough, a planetisimal, its gravity gives it a spherical shape. Its core comes under tremendous pressure. This once again acts like a mass spectrometer! And the various compounds at the core again differentiate. Lighter stuff perculates up. Denser stuff sinks down. The core heats up. At temperatures above 2000 F, compounds of iron give up their C, O, H, Si, S and other lighter elements, leaving only elemental iron. Iron is denser stuff. It sinks down.

Similar processes are going on in the regions of the gas giants and transition planets. Only those planetisimals not only scoop up dust as they whirl around, they also scoop up the lighter gases, H and He. At first, this is easy because they are still so cold that the gas pressure of even He isn't enough to escape a planet with, say, Earth's gravity. They grow fast, becoming gas giants like Jupiter, with a tiny iron/rock core. By "rock", we mean any substance (not the pure metals) that tends to be a solid at temperatures above the freezing point of water and below, say 1000 F. For example, Silicon Dioxide.

By the time the fusion-flash is over, and the sun warms up to its full equilibrium state, most of the gas giants will have enough gravity to hang on to their H and He, even as they warm up a bit.

So, that's where all the iron came from. Even though it is only .0001% of all atoms in the universe, there are (at least) two mechanisms or processes around the newly formed star that tended to act as a mass spectrometer, or a mass differentiator, separating out the heavy stuff from the light. Iron in close orbit to the sun tended to stay there after the fusion-flash, whereas the lighter stuff tended to be driven further away. And the cores of planetisimals, if their temperature got high enough, tended to melt and accumulate iron, and drive the lighter stuff upwards towards the surface.

The Universe is full of wonderful and totally natural processes that separate, differentiate, purify and accumulate matter. Heads up!

[stereologist]

Very interesting Pyrotex. I suspected that the segregation of elements was due to either some effect of denser elements moving towards the center of the rotating disc or the sun forcing lighter elements away. I think I was a little right in my guesses.

I think the 0.1% I had for iron was mass, not numbers of atoms.

[Moontanman]

I got the idea that CharlieO thought an already formed Earth acquired it's iron through meteor impacts. Instead as Pyro pointed out the Earth formed from debris that already had a high proportion of iron, not from impacts after the fact. I've seen many people who seemed think this, it's also important to understand the Earth Orpheus collision allowed the Earth to acquire a huge amount of iron while shedding a more than moon sized mass of lighter elements and water, leaving the Earth with a larger than average core for it's size and higher average density as compared to say Venus. In "Rare Earth" by Ward and Brownlee they propose the Earth would have been a water world without this collision and the Earths large core contributes to not only it's Magnetic Field but to Continental Drift as well.

[CharlieO]

Turtle wrote: Anyway, we're just not going through all this again. The simple fact is that this earth-core-not-iron bit is all based in Fundamentalist Christian Creationism and at Hypog that doG don't hunt. Will the staff be so kind as to move this thread to Silly Claims where it belongs?

Turtle, I admitted I was puzzled about the belief of Earth's core being iron and the only two related theories I knew anything about seemed illogical to me, even absurd. Then I asked if anyone had a more plausible theory. Just a simple question, hardly a claim about anything or any need for anyone to go thru an earlier thread's subject. Seems to me you don't understand a simple question made in all sincerity or perhaps you don't know of any other theory and prefer to insult instead of inform. That's your problem. Please stop trying to switch the issue. That dog sure don't hunt and appears counter to the expressed intent of this website.

Pyrotex, Really impressed with your explanation. I always appreciate learning something new. Doing better than most at 76. You make a good teacher. Wish you had been my major professor instead of the dogmatic types who stated their geophysical beliefs as being set in stone; many of which have been overturned with more recent discoveries. I sincerely appreciate the time and effort you expended and will give your words sincere thought. Still not exactly sure about what you proposed, but I can't thank you enough for the information and will try to understand it better over the next few days.

Hard to find time for same, due to being a 24/7 care-giver, with the only time I have to spare is when she is sleeping with the breathing machine and monitor.

Any other theories available?

Best Regards to those who responded in a positive and informative manner. CharlieO