http://www.sciencedaily.com/releases...0109075137.htm

Any comments from those more knowledgeable than me?


<font size=-1>[ This Message was edited by: ToSeek on 2002-01-09 11:36 ]</font>

Hm.. I guess it isn't impossible...

When I was taking cosmology, the prof gave us the four equations that can be solved to give the interior conditions of a star... Pressure, temperature, gravity, um...mumble... something else... (It's been a while, and I was a maths student...) If the sun had a solid, non-fusing core, the equations would have a different solution, and (in theory) the sun would have different characteristics...

Also, since the sun is, to most appearances, a fairly ordinary, if somewhat brightish, star -- wouldn't the same origin be necessary for all G0 stars?

Heavily dubious...

Silas

That news release says that he has been trying to convince others of that hypothesis for forty years. The evidence for it can't be too strong--maybe the latest is stronger?

Some of his theory isn't really new. Now, is it or is it not true that heavier elements are cooked up in the cores of larger stars and get scattered to the cosmos when those same stars explode? So naturally one could assume that our solar system with its abundance of heavy elements (relative to what? I don't know) came from the dusty remains of an ancient supernova.

What bucks intuition is the implication that our sun then formed around the remaining supernova core. Afterall, aren't the remnant cores of supernova also supermassive, many times the mass of our sun? Aren't they spinning neutron stars, and any mass falling on them would be crushed also to neutron density? Or am I missing something?

I'd have to hope that he's only talking about iron that originally came from a supernova core, scattered to the nine winds, and gravitationally clumped along with all the other star stuff when our sun began to form...

If one phrases it "weakly," sure, it makes sense: the gases in space are richer in iron, now, than 12 billion years ago, and thus newer stars have more iron in 'em than old ones did.

(Just as babies born today have radioactive strontium and cobalt and uranium atoms in 'em because of bomb tests, whereas babies born in 1940 didn't have 'em...)

If *that's* all the guy is saying, then it's old news... So I 'spect he's got a lot more in his bonnet...

Silas

No, he thinks the Sun is mostly iron.

I have many, many problems with this theory. One involves formation: does every star form this way? That implies billions of supernovae, and also brings uip a chicken-and-egg problem; how did the first stars form?

If the Sun is special, why? And why does it look spectrally just like a lot of other GV stars in our neighborhood?

I have not read his paper in detail, but he makes a point of there being too few neutrinoes from the Sun. This is an old problem, and may very well be solved with neutrinoes having mass (they change flavor on thier way from there to here, so we don't detect 2/3 of the ones created int he solar core). And how does his model produce the neutrinoes we do see?

I have been to some, um, alternative talks at AAS meetings (where this was announced) and I am quite sure others brought up these and similar points. I doubt that will make a press release though.

The BA's points have been made and many others have been repeated many many times to the person in question.

He doesn't have a working model for his Iron-Sun, only a basic idea, a disputed interpretation of isotopic ratios, hand waving and back of the enveloppe type arguments. I personally give no credence to his idea until he actually gives quantitative predictions for helioseismology and abundance evolution in the Sun and the solar system.

As far as the Sun being a nearly unique object in the Universe, why not? But then again why? A few isotopic ratios are not convincing when the rest of astrophysics argues against his idea.

I guess the implication would be that only stars with rocky inner planets would be formed this way. Stars without planets or stars with inner gas giants would form by the standard model.

I don't have so much of a problem with the idea that buried deep within the heart of the sun is a core of solid iron plasma. (Wouldn't heavier elements sink to the core of the sun just as they do on other worlds?) And we may never see it or detect it because we can only see the outer shell. But the author suggesting that the main source of heat of the sun comes from gravitaitonal compression of this iron core (like what powers the fires deep within our own world) is a bit of a stretch.
I guess that's why it's here in "Against the Mainstream". eh? [img]/phpBB/images/smiles/icon_smile.gif[/img]

It's interesting to note that one of the first scientific theories of the sun's composition was that it was a ball of iron glowing white-hot due to gravitational compression.

That theory was abandoned in stages; first, because it wouldn't stay hot long enough for the 5 billion year age of the Earth (as deduced from the ages of the oldest rocks); second, spectroscopy showed the sun's light was primarily from ionized hydrogen, with a dash of helium; and third, our understanding of thermonuclear reactions provided an abundant source of energy that would last over geologic time.

I don't think the discrepancies in the current model of solar functioning are large enough to suggest such a radical reinterpretation.

One silly question: if the planets are made from detritus ejected by a supernova, what made it stop so close to the sun? Why isn't it all rushing madly away from the supernova remnant at ludicrouspeed?

I'll take a stab at some serious thoughts here. (adjusts glasses, ahem)

While I'll grant to Dr. Manuel there is a "small" ball of Iron at/near the core of the Sun, I find it highly doubtful that it is a major component.

If the Sun were infact mostly iron I think it would show up in the mass-to-volume (density) ratio. Per my "baby astronomy" class in college, the density of the Sun is consistant with a compsition of 99.XXXX% hydrogen.

Does anybody know if it is possible to calculate if it is possible for the Sun to look/behave as it does, having a mass that is (arbitrarily selected) 51% Iron? I select 51% because it is the minimum whole percentage that permits the Sun to be "mostly iron" as Manuel claims.

I have no scientific calculations to support this but my sense of the "Force" is that the answer is no. An iron ball with 51% the mass of the Sun would have a huge surface gravity and would cause the Hydrogen layers to fuse faster and, therefore, release more energy than is currently observed.

Anybody have any better thoughts?

__________________
It's just one of those damn things of which there are many few. -- Dan Blocker

That's not silly at all! Remember, though, that the first extrasolar planets discovered were around a pulsar, a supernova remnant.

Not all of the star blows outward; there can be a "stalled" part that can recollapse onto the remaining remnant (neutron star). Some theorists think this material can be enough to further collapse the neutron star into a black hole! But there is evidently (literally) enough material that does not escape to form planets in some cases.

Not that I am advocating this guy's theory. I just want to note that some objections to it don't really apply. There are already enough problems with his theory!

Although I agree there is evidence for the possibility of planetary formation after a SN Dr Manuel's idea as he states it requires that the matter from which the planets form are chemically differentiated, i.e. heavy elements near the SN remnant (the proto-Sun) and lighter elements on the edge (to allow the formation of giant planets). AFAIK there is no evidence for this.

On a similar topic, he argues that the Sun was also formed as a chemically differentiated object and not homogeneous as is generally assumed based on our coarse understanding of star formation.

As far as the iron core goes, helioseismology constrains the temperature in the core to better than 1%. The PP reaction rate has a quoted uncertainty of a few percent (5% max if memory serves). If one screws with the chemical composition of the core, one cannot reproduce the seismic Sun. One then has to postulate other wierd stuff such as unforeseen physics dealing with opacity, equation of state or nuclear reactions. While not impossible, it seems improbable. And the more recent solar neutrinos results from SNO would confirm our current understanding of solar physics.

One other point, non-standard models of the Sun can be made for the current Sun. That isn't too hard, just tweak the structure a little and correct the sound speed with other tweaks and so on. The trick is to have the non-standard models agree with the current Sun after 4.6 billion years of evolution when the non-standard physics has a good chance of changing the way the Sun evolves (wrt standard models).

This is not my theory but in the book I am presently reading the author mentions that all stars have cold cores .
He notes that the super giants such as Betelgeux and Antares contradict present theories of star formation because these stars having huge masses somehow did not adhere to the effects of gravity whereby a star such as our sun accumulated its mass and when its supposedly nuclear core ignited then it pushed away the remaining debri to later form our planets .This then he states must mean that gravity has an ignition limit, that is to say that no matter how slow or fast a proto star forms then the pressure is built up to the same point of ignition hence this means that the two huge stars mentioned above accumulated their mass contradictive to gravity and its effects , how then could these two stars acquire their masses ! .

I tend to agree with the author that we presently observe that all things burn from the outside inwards so his theory that stars have cold cores seems feasible to me that the two mentioned stars are not two bloated super giants but just two huge stars whos ignition burning from the outside inwards is only at the molten stage and is then the reason why these stars are red , but hey you make your own mind up or read the book because I am open to all kinds of open minded views and find this alternative theory feasible and I tend to agree in parts or should I say it opens up new areas to investigate .

Emporer, please post the name of the book and its author. I'm curious.

It's true that in most cases one only has direct observations of the surface of stars.
In the Sun however, one has meutrino emission which is emitted directly in the core and which might be held has evidence for a cool, but not cold, central core. Helioseismology is also a fairly direct 'observation' of the solar interior. It is an interpretation of surface observations but the theory is fairly straightforward.

The seismology of other stars is also can also be considered in the same way and more and more stars are studied that way and nothing exceptionally surprising has been found so far.

Finally, looking at many stars in clusters enables us to test fairly accurately stellar models as we compare stars of different mass and evolutionary stages but same age and initial chemical composition.

All the evidence so far points to the fact that our models of stellar structure and evolution are pretty good. I know of no alternative model which even attempts to reproduce the wealth of observations that standard models do.

Bad Bad Astronomer, Phil! You mispelt his name!

The (spelling police 'r us) Curtmudgeon

[quote]
On 2002-01-10 13:03, The Bad Astronomer wrote:
Emporer, please post the name of the book and its author. I'm curious.

Sure but I did provide the link to its introduction to emphasize a point it makes . its at http://www.spaceskeptic.com/ebook/ebook.php it also turns out that their are two site links one being http://www.spaceskeptic.com and http://www.spaceskeptic.co.uk . Have been trying to get back on the site and could only find it through http://www.google.com .

Have tried sending the author a message but their is no link or address except through a private message on the forums , perhaps you may have more luck than me , I registered as starman because I believe I have had contact with the author on another site .

This fails to explain Kuiper belt objects and the Oort cloud, where most of the solar system's non-gaseous mass is located if you don't count the Sun.

I don't see how "strange xenon" could not be formed by a nearby supernova. There seems to be no direct evidence that our own Sun was the producer.

Of course he could be right, but it sounds to me like he wishes the Sun was more unique than it probably really is.

And, of course, it would be a real pain to form gas giants, let alone four of them, under the conditions he thinks formed the Sun.

Emperor, is that book you mention the one by a certain J Reyes? The J Reyes who apparently is also known as Emperor (as pointed out by DStahl)?

<font size=-1>[ This Message was edited by: Argos on 2002-01-16 19:14 ]</font>

"If the Sun is special, why?"

I suppose you could use a version of the Anthropic Principle here. If iron-rich stars are the ones most likely to form rocky inner planets (as opposed to close orbit gas-giants), then given our current understanding, they're the ones most likely to have life in the system able to observe them. Sel