duane has done some great work looking at Dr. Manuel's claims about the Iron Sun theory, that basically says that the sun is not the same as most stars, and is a collection of mostly heavy elements with a hydrogen atmosphere. Note, most serious astronomers regard this as a crackpot theory, but Dr. Manuel is willing to take the time to try and defend it. In it's favor, it does offer something of an explanation to some isotope abundance anomalies among other things.

You can look at a number of web-sites about this theory. Pointers to them are in the previous posts in this thread. I suspect that Dr. Manuel is sincere in his belief in the theory, but in this discussion, I am hoping we can shoot it down [or prove it] without shooting at Dr. Manuel, who has demonstrated that he is a gentleman.

Previous posts in this thread can be seen in the Story Comments -> Discussion: Spitzer looks at a Stellar Nursery
http://www.universetoday.com/forum/index.p...?showtopic=2435

Personally I found this discussion interesting enough that I wanted to pull it out into a properly labelled thread. Note, Josh has suggested moving this thread to Alternative Theories, and I agree it blongs there. I don't know when the move will be made.

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Is it possible for air to go through when the Sun is burning Iron to Helium?

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We come without a thing and gone without a thing. We need simple life. A cup of teas and a couple of meals per day, that is good enough. And this is my standard of living.

I'm sorry Tiny, I have no idea what you mean.
- Is it possible for air to go through what?
- I don't think the sun ever burns Iron to Helium.

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Here's a link to a long article [32 pages] about an observed Iron Sun.

http://www.arxiv.org/PS_cache/astro-ph/pdf...403/0403402.pdf

This star is a close binary 0.7 solar-mass companion to an 11 solar-mass black hole. The article guesses that the star was enveloped by the pre-supernova and spiraled in through the thin outer layers, and that the supernova happened before it coalesced into the core of the giant.

The article reports an Fe/H ratio of 0.14 +/- 0.12. Since Iron is substantially heavier than hydrogen, this means that much more of the mass of this star's atmosphere is Iron than is hydrogen.

I think this example shows that an Iron Sun is possible, but doesn't speak well for the likelyhood that our sun is one of these, as we don't have a large black hole orbiting our sun, and we don't have much iron in the sun's atmosphere.

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okay, this may be a silly question, but waht exactly does the sun burn iron into? if anything

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Damien,
International Baccalaureate Physics teacher
Optics, Photogrammetry and Remote Sensing Instrumentation Major
Admin: Pacific Science and Art

To nickel I think, or else will be Cobalt...

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We come without a thing and gone without a thing. We need simple life. A cup of teas and a couple of meals per day, that is good enough. And this is my standard of living.

Normally, Iron is the end of the line until it collapses into neutronium.

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okay, next silly question, what is neutronium?

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Damien,
International Baccalaureate Physics teacher
Optics, Photogrammetry and Remote Sensing Instrumentation Major
Admin: Pacific Science and Art

Why do you consider this a silly question? Last time I asked that question, the answer was "nobody knows". It could be completely fanciful, and apparently can't be created in a lab. It doesn't stop people from talking about neutron stars as if neutronium exists. Neutron stars are apparently the last stop before a black hole.

Cheers.

Sorry for the slightly glib answer. My intent was to convey the idea of the material that makes up neutron stars, which is a dense soup of neutrons, protons, electrons, pions, etc, all bound gravitationally to a degree that the nuclear forces are overwhelmed.

The actual word neutronium is a science fiction term, which was actually out of place here.

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Ok, but I would really like to know how we can be sure that matter can exist in this "neutronium" state; this soup of neutrons, protons, electrons, pions, etc. My guess is that this form of matter is the result of putting in higher numbers in the equations and see what comes rolling out, do we have any experimental evidence that matter can be compressed in this way?

Cheers.

We have some indirect observational evidence. There are objects which spin around 250 times a second, and weigh about the same as the sun. If you assume that the equator on its surface is spinning at 20% the speed of light [a guess at the fastest possible spin rate], what is the space between atoms?

2e33 grams times [solar mass] 6e23 protons per gram [mole] is about 1e57 protons or neutrons.
0.2 [10 percent] * 3e10 cm/sec [speed of light] / (2pi * 250) = 4e6 cm radius.
volume = [1.33 * pi * r*r*r] is about 3e20 cubic centimeters.

This gives 3e36 nucleons per cubic centimeter.

This puts the average space between nucleons at about 6 femtometers, which is well within range of the nuclear forces. The space between normal atoms in a solid is about 20,000 times more sparse [0.1 nanometers].

More accurate, detailed, and less simplified analysis can be found on the web easily enough.

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You mean pulsars? They are assumed to be spinning, but maybe what we see as pulses is not the result of a spinning object. It seems to me that "neutronium" (what is the proper term btw?) is needed to explain the excessive spin rates. Just suppose there is nothing spinning that fast, doesn't it follow then that there are no neutron stars? Well, I must correct this, neutron stars are entities with specific characteristics, they are real. What could be different because of our assumptions is that they're not containing any collapsed matter. So what is eliminated then, is the need for an exotic form of matter.

Cheers.

Yes I mean the millisecond pulsars specifically. These are the ones that are spun up to faster rates by infalling matter from a companion.

If you assume that these things are not spinning, but are sending out very regular signals by some other mechanism, I'd like to see a suggestion for the mechanism. You are still required to have the energy source for the pulse be less than a kilometer across based on the pulse time. That's a lot of energy to get out of a small space in a short time.

Also, as to neutron star size, take a look at the observations of Geminga. This is an old neutron star that is glowing with the right color and brightness to be a black-body radiator. It has an observed opitcal counterpart. Because of proper motion studies we can make a good guess as to its distance. The size determinations are pretty solid scientifically.

One last note is the question: How could a neutron star could form without taking on a high rotation rate? Our sun spins once every 27 days. How fast would it spin if the radius shrunk to 1e-5 the current radius? Note that angular momentum must be conserved.

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Sorry Antoniseb, can't help you with another mechanism just yet. I wouldn't be surprised if another mechanism exists, but apart from the Electric Model (see other threads for it's discussions and debunking), I don't know of any. Doesn't mean that the spinning assumption is true though, I'd like to see better evidence then pulses (millisecond pulses because of rotation seems like a ludicrous idea to me), or some way to verify collapsed matter experimentally before I accept neutron stars as composed of "neutronium".
We're drifting away from the Iron Sun model, of which I'm still unsure why the measured isotopic ratio's must mean that there is something wrong with what we know of stellar evolution and the history of the Solar System.
Maybe it would be helpful if we compared the 2 models step by step, then maybe I'll be able to see at what point the models diverge, or if there is even anything compatible at all.

Cheers.

Here's another set of questions for Dr. Manuel on this Iron Sun stuff:

Are you saying the the core of the sun is:
- a white dwarf [this is the one I assume you mean]
- a neutron star
- something else

If the mass of this core is less than 0.5 solar mass, how did it form?

Do you believe that the chemical abundances in the photosphere are different than what is commonly reported by main-stream astronomers?

If not, how deep into the Sun's interior do we need to explore before we start seeing very high Iron abundances?

Is there a layer in which thermo-nuclear fusion is occuring? How far from the center is it? If not, how long can the sun maintain approximately the same luminosity? How rapidly will this be changing?

Do you believe that the density of the photosphere is different than what is commonly reported by main-stream astronomers?

If not, how do you plot the temperature and pressure along a solar radius such that the mass of the sun works out to the observed value of 2e33 grams?

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Dr manuel states:

I would add in Dr Manuel, that measurements do not support your contention that the earth accreted on an iron core, rather measurements almost universally support the premise that the earth accreted and then melted, resulting in the formation of an iron core.

Further, you have given no mechanism by which silicates formed farther out from the earth's early orbit could have migrated in to accrete on the newly formed iron core, nor have you given any explanation for the how a lack of differentation would have occurred in the aftermath of the proto-earth having been struck by a mars-sized body.

Recent measurements by Romanowicz et al at the University of California, Berkley have identified hot "superplumes" of material rising from the lower mantle (~ 2800 KM below the lithosphere) and earlier measurements also identified cooler "downplumes" in other areas of the planet.

William White at Cornell also found evidence of mantle recycling in measurements he and his team performed at the Society Islands, and this finding was reconfirmed later by Jon D. Woodhead of the Australian National University through measurements he made of the abundant oxygen isotope ratios at Pitcairn Island.

This could not be the case if the lower mantal remained undifferenciated and/or unmelted as you maintain.

There are a myriad of other studies which also support the premise that the lower mantle is melted. This must also lead to the conclusion that the lower mantle is differentiated, because it could not remain undifferentiated while melted.

Now no doubt you will again refer to your paper regarding the anomalties in the isotopes of He and Xe. Might I suggest that you instead refer to some independant findings from anyone other than you and your collaborators so that we might gain an unbiased view of your findings?

Might I also suggest that you outline a mechanism whereby the isotope readings you obtained might have arisen in the accretion method of planet formation? Or is it your position that such readings are impossible in that method?

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All civilizations become either spacefaring or extinct.~ Carl Sagan ~

Humanity must rise above the Earth, to the top of the atmosphere and beyond, for only then will we fully understand the world in which we live.~Socrates, 500 B.C. ~

Let every man judge according to his own standards, by what he has himself read, not by what others tell him. ~Albert Einstein~

Oh by the way, what is the spectral line for Iron look like?

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We come without a thing and gone without a thing. We need simple life. A cup of teas and a couple of meals per day, that is good enough. And this is my standard of living.

Oh! Dr. Manuel, I see in your papers that you postulate a neutron star in the sun's core [These must be at least 0.88 solar masses]. That makes the mass of the sun very difficult to get to be only 2e33 grams. Do you have a theory about the structure of the sun that accounts for this?

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Thanks for all the comments and for an open discussion about evidence for and against an iron-rich Sun.

I received two e-mails last night asking why I had not responded.

The answer - I did not even know the site existed! Now a lot of material has accumulated and I need to start responding in a manner that will convey information clearly and concisely, despite other commitments on my time.

Physics On-Line also has a discussion about evidence for and against an iron-rich Sun and posted a lot of background information there. Am I allowed to post that link here? :blink:

http://www.physlink.com/Community/Forums/v...m=18&topic=2421

In case it is edited out, I will go ahead today and give readers biographical information on the events (1936-1959) leading to my interest in nuclear energy and the Sun.

When you reach my ripe old age, I suspect you too will look back on life and realize you had little or no control over your life, your career choices, successes, or failures.

I "decided" to be born in 1936 when, on the other side of this globe, Francis William Aston went to Japan to observe a solar eclipse. He also presented a lecture at the University of Tokyo, which sparked the interest of an unusually talented 19 year old student named Kazuo Kuroda in nuclear energy and the Sun.

World War II followed. As a young child I was taught to hate "Japs" and "Nazis" on this side of the globe. Kazuo Kuroda completed his education on the other side and became the youngest scientist appointed to the University of Tokyo faculty. The atomic bomb ended the War. Dr. Kuroda was sent by the Japanese government to investigate the bomb site and report back the nature of this new weapon.

The US government realized that knowledge is the key to national security - - - something that has since been forgotten! We stole ("relocated") the best scientific minds in Germany and Japan and brought them to this country. One was given the Christian name "Paul" on the boat ride to this country; the rest of his name looked strange to Americans - - - Kazuo Kuroda.

Kuroda landed in San Francisco and met Glen Seaborg of Berkeley National Labs (BNL). Seaborg wanted to hire this talented young scientist, but was prevented from doing. Kuroda was Japanese, and the US government wanted a monopoly on nuclear secrets. [Only in 2002 did they learn that Kuroda carried secret Japanese plans to build an atomic bomb there!] Americans of Japanese decent had been locked up during the War. No Japanese citizen could work at BNL.

So Kuroda ended up teaching at the University of Arkansas.

Meanwhile, life had been hectic for me. I grew up like an alley cat or a weed, and did not finish high school. By accident I was admitted to Pittsburg State College in 1956. My best teacher, Jim Pauley, taught General and Physical Chemistry. He was also a graduate of the University of Arkansas and directed me there when I graduated in 1959.

That is how "I selected" one world-class scientist, Paul Kazuo Kuroda, as my mentor and another, Francis William Aston, as my academic grandfather. They, of course, directed my attention to Nuclear Energy and the Sun.

With kind regards,

Oliver
http://www.umr.edu/~om

PS - Responses to questions raised in earlier postings will depend whether or not I need to reproduce here background information given on PhysLink.