A young sun - a response

Are they telling the same story? Well, yea, approximately.In you Dallas example, do all sources agree on the number of tires on the car? Yea. Do we agree that there was a start to the earth? Yea.But if one eye witness testifies that the car had 7 (a mystical number) of lug nuts and the blueprints for the car and the historical documents of it's conversion to the president's car all tell us that it had 5 then the witness has to agree that his/her memory might not be right.If we don't have the eye witness to talk to but have records written by others taken from an oral tradition from individuals that didn't talk to the eye witness then we can pretty much bet that the memory isn't right.However, all of that is beside the point. The point is that the Bible is NOT trying to tell us how old the earth is, how the sun shines or anything of that type or at least that is a reasonable way to accept the Bible. Even if I believed there was a God I wouldn't expect that the Bible would be worded to supply that information. I wouldn't expect it to be trying to teach nuclear physics to goat herders for pete's sake.So if there is any apparent disagreement between nuclear physics and the Bible it just doesn't matter. The physics is the best answer we have. The Bible answers other questions for those who need those answers in that way. We are, I think, in complete agreement that the Bible shouldn't contradict the evidence we have but I don't believe it should matter enough to even ask the question.Galileo pointed out that if the scriptures appeared to contradict the evidence it was the human interpretation of the scriptures that were wrong not the scriptures. I say, it doesn't matter. In that regard I would be supporting the "non overlapping magisters" that Gould talks about.

1) Intial fusion reactions question.Gavitational collapse was the initial energy source of the proto-Sun. As the gas heated the temperature in the core reaches approx. 10,000,000 K. This is approx. the onset temperature of hydrogen fusion. Thus since the core is the hottest it began here. (Note the fusion reaction rates are a very sensitive function of temperature approx. T^5 for pp chain hydrogen fusion). I have neglected deuterium fusion which briefly occurs before this but this is rapid and the deuterium is quickly used up.Also note that if the mass is less than approx. 0.08 solar mass the temperature never reaches this high. Thus you get a brown dwarf.2) Core energy production question. (The response here refers to the present day Sun)No the energy production is not linear within the core. Due to the reaction rates being so temperature sensitive and the temperature being higher towards the middle the energy generation is concentrated more towards the centre. In fact all the generation is within the central 1/3 of the Sun. It is a power law function. Thus if you plot the logarithm of the energy generation rate versus radius it is a straight line (approx.)At 1/3 solar radius this has dropped to approx. zero. This is a sharp transition due to the sensitive function of T.Here I shall clear up some errors posted on solar structure.0 - 1/3 solar radius - energy generating core - radiative transport of energy. (In a more massive star >1.2 solar mass, the core gets progressively more convective as the mass increases - our Sun does not have this (though it did in the past))0.33 - 0.72 solar radius - radiative zone - energy transported radiatively but no energy generation here0.72 - 0.999 solar radius - outer convective zone - energy transport by convection0.999 - 1 outer radiative region (can be ignored for this discussion)3) Core volume question.The core volume isn't changing much BUT the important thing is the Helium content is rising and a small Helium core forms. As this grows the hydrogen fusion occurs in a shell around this and the helium core just sits there, growing. This happens until the central temperature increases to where Helium fusion can occur (100,000,000 K)It get's complicated now and space doesn't permit. Helium flash, shell burning, triple alpha process etc.4) Core density question.Density is approx. 120 grams per cc in the core. This decreases as approx. a power law to about 0.1 gram per cc at 0.8 solar radius - then falls very quickly after that. Note average density of the Sun is approx. 1 gram per cc (i.e. about the same as water)Plasma is NOT a liquid but can be described mathematically as a fluid. Remember it is all fully ionised - protons, helium nuclei and electrons. It does not make much sense to talk about atoms as such.More to follow in next post.

1) Magnetic question.Magnetic field discussion of the Sun needs to be split into two parts.Part 1) Observed magnetic effects (sunspots, coronal heating etc) are small scale phenomena associated primarily with the outer convective zone and the 'atmosphere' of the Sun. Field strengths are really not that high astrophysically.Part 2) Internal deep interior fields. Largely unknown but important for angular momentum transport and mixing processes. This does put strong constraints on their strength based upon solar spin down and light element (lithium/beryllium) abundances at the surface. The fields are probably weak BUT present. Lot's of dynamo models of this.Magentic effects in the core unimportant for energy generation. The magnetic diffusivity is so high that a field quicky dissipates in these central regions and in no way effects fusion reaction rates. Also rotational mixing is so strong that these fields have no structural effects here.Further out this isn't true but it is a complex area that space doesn't permit explanation here. Plasma pinch instabilities, differential rotation dynamo, initial poloidal peturbation becomes new toroidal field component i.e a dynamo, equlibrium with external Weber-Davis wind torque etc etc etc2) Holding it together question.Hydrostatic equlibrium! Sun is in a balance between gravitational collapse and gas pressure from energy generation by fusion. Also some radiation pressure (more important in massive stars). This is very stable. If it wasn't the Sun would noticeably change in 30 minutes.3) No other force. The magnetic stresses/tension is negligible. Don't forget, GRAVITY. The Sun has a lot of mass (1.9891 X 10^30 Kg) that wants to contract. Then it was not a balance. the Sun was in a hydrodynamic stage where gravity was winning versus gas pressure until enough heat generated for them to balance.Forget magnetism. Just negligible for the early or current Sun.4) This question doesn't make much sense.Convection currents and magnetic field interaction is complicated. But remember, ionised material wants to travel along field lines and it is more difficult to cross them. This is a built in anisotropy. But mass motions, if powerful enough, drag field lines with them, leading to dynamo mechanisms and material/angular momentum transport.
COMPLEX.

No helium and hydrogen don't fuse directly. (I should say yes but at a very very small level)Many reactions can occur but only certain ones are important. Not space here to explain the nuclear physics of why some are important and some not. See Clayton 1968 Introduction to Stellar Nucleosynthesis.The Lithium is important because it is all destroyed on production in the core. Thus lithium that is in the Sun is primordial and it's surface abundance is a probe of stellar mixing and transport processes. (same for Beryllium).You know what the Sun had initially from meteoritic values.

Kippenhahn & Weigert - Stellar Structure & Evolution (Springer-Verlag)A great book, for the most part. Not much on mixing and rotation though - that is pretty much only in the technical literature (ApJ, A&A etc)For the brave of heart - Principles of Stellar Structure - Cox & Guili 1968 - (2 volumes - great detail - heavy on theory - damn expensive $1100)

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What I do know is that as a star starts to run out of hydrogen it can start to collapse further under gravity. This produces new, higher pressures and temperatures. This allows for more fusion processes and then more again. Soon there are a number of them going on in the star in layers. IIRC the red giant phase of the sun will be produced as these other processes start to occur.

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Let me see if I can remember more details off the top of my head.A main sequence star "burns" hydrogen into helium. The helium is "heavier" and so displaces the hydrogen at the very core: it basically "sinks below" the hydrogen. When the star converts enough of its fuel (hydrogen) into something it can't "burn" (helium) there is an inner helium core surrounded by a hydrogen shell. Only the hydrogen shell is undergoing fusion so the nuclear furnace slows and so produces less outward pressure. With insufficient means of countering the force of gravity, the core begins to contract. This heats up the core and when the termperature gets high enough, the helium can begin undergoing fusion. This realease energy and heats up the overlying hydrogen shell. Thus, becuase of core contraction, the helium core and the hydrogen shell "burn" fuel and the outward pressure increases dramatically. This overcomes the "pull" of gravity and the star - its envelop - expands, creating a giant and eventually a red giant.

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If the star is big enough ( I think it is about 8 solar masses) the whole thing can get to the point of being able to force the fusion to produce iron. However, this doesn't release more energy, it requires more than it produces.

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Up to iron (iron-56, I believe) fusion releases more energy than it requires. Above iron it takes more energy to make the element than is releases by fusion.

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From the blown off material we get all the elements heavier than helium that make up the earth and us.

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Yes, and such stars require certain conditions, such as having the four fundamental forces of nature to each be within a very narrow range. If even one of the fundamental forces (or several other constants of nature) were only slightly different, then the appropriate type of star would not form, which means there would be no carbon or oxygen, which means there would be no organic compounds, which means there would be no life as we know it. In fact, without the blowing off of elements heavier than helium, there couldn't even be silicon, or aluminum, or sulfur based life.[This message has been edited by DNAunion, 11-21-2003]

It sounds like achiving a stable Sun that doesn't blow itself apart is fairly straight forward. You have 2 forces that will always find equillibrium. The expansive pressure will be counteracted by the gravitational colapse and the more solar mass you have the greater the collapse. The greater the collapsive force the hotter and sooner the fussion core developes increasing the convection energy and overall star temperature which stops the on slaught of collapse by gravity.That's surprisingly simple. Another question then arrises. Do all stars appear to have the same average density as water, as our Sun does, reguardless of it's solar mass?

I'd hate to see the guy's hand who had to hold the thermometer in there that deep!

no - in fact more massive stars have a smaller central densities.And yes the basic balance leading to hydrostatic equilibrium is simple.

Thanks for taking as much time as you did to answer my questions. I've got some knowledge now to go back to those web sites and re-study the info on solar dynamics. Thanks again for your time.

Lizard Breath says:

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The Bible is like the eye witnesses. The book of Genesis and primarily chapeters 1-3 are a spoken testimony of what happened given by one individual - God, or so the book claims. The account is in the perspective of the witness, again God.

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I look at it as the stylized account written long after the 'fact,' like the Mailer or DeLillo novels that put the Kennedy assasination into a certain network of historical or philosophical reference points.

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In the same manner the Bible isn't going to explain hydrogen fussion in the sun's core but it should not contradict the scientific model of the sun by saying it is 10,000 years old while science verifies it is 4.657 billion years.

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Why wouldn't it contradict the scientific account? The writers of the Bible had no knowledge of nuclear fusion, and few people would assert that the Bible is meant to be read as a science book. Are you saying you'd think less of the Bible if it doesn't make scientific sense? That would sound strange coming from someone with a mature, realistic faith.

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That's what I'm hoping to get at, is finding out if both science and the Bible are indeed telling the same story.

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And what if they don't? Do you scrap your faith or mangle science to fit your wishful thinking? You could always put the two in their proper places and realize that one should speak to your soul while the other enriches your intellect. But you want it all in one convenient package, regardless of whether it makes a mockery of faith and science at the same time.------------------
The dark nursery of evolution is very dark indeed.
Brad McFall

Darn! You say what I've been trying to say so eloquently! Thanks.

ditto

From what I gather about what the Bible says, it is an intellegent faith that requires the believer to do 2 things.1) confess with your mouth - which is what just about anyone is able to do whether they actually believe anything or not. Turn to any channel on Sunday morning and you can here anything from genuine Biblical teaching to blantant chacanery to get into your wallets. I've even seen people at my place of employment do the confess with their mouth routine and it becomes obvious that they don't even know what they believe, let alone actually believe it themselves. The confessing is the easy part from my perspective.2) The second thing the Bible asks is believe with your heart. This is where the rubber meets the road. Notice that the Bible doesn't say believe in your head, or believe in your cerebral hemispheres or have a sound logical defendable ideology. It says believe in your heart and be prepared to give an account of what you believe at all times.So what is believeing in your heart? That's the key dynamic to dealing with the Bible. Well, when God spoke to Moses in Exodus, he told Moses what to go and do and naturally Moses resisted as I would have. So what did God do. He didn't say "have faith in my word and go against the odds and just believe despite what the evidence around you supports" that Moses was going to get his head cut off if he asked Pharoh to release the Israelites. So he gave Moses something to work with and he told Moses to hold out his hand and you know the rest of the story. These kinds of demonstrations are throughout the Bible where God gives specific people what they need so that they "Believe in their heart" what they believe and not just have a head knowledge.Today we have something better than a supernatural demonstration to add to our faith. Since Christ died for the sin debt, God can now approach us again as before the fall, so the Bible claims that the Holy Spirit personna of God actually makes a home in our heart. Now I realize that there is no literal dwelling in my coronary system, but many would say that if you take the Bible literally then you must believe that there is now a structure in one of the chambers of your heart where the holy spirit is hanging out. A CT will not reveal this "house" so is my faith busted? No, it just shows that God uses many different forms and illustrations to try to convey principles to a 3 dimensional being from a creator unrestrained by dimension.The biggest aspect of God that people fail to give attention to is God's holiness. If you do a study of how infinitley holy he claims to be and how unholy even 1 transgression is and how unapproachable he says that he is to any transgression, you start to understand why the Old Testament and the Gospels were filled with the supernatural. That was the most efficient way to give his people a faith they believed in their heart. But now that the debt is cleared, the most efficient way to build a heart dominated faith is with the Holy Spirit living - touching our own spirit.So if you have that kind of faith, not just a head knowledge faith, when you explore what science is saying, you don't cut and run and give up your faith when it doesn't look too good for God. That's what a head knowledge will get you, or the "believe it against the odds" kind of faith. The Bible is clear that it doesn't want that kind of believer and those types are addressed at the last judgement by God. So I don't trash my faith, but I continue to explore because the truth is indeed out there and it will be revealed - discovered.So when the Bible gives an account for creation - it's pretty important to deal with it and if the scientific evedence says it's 4.657 billion years old I don't say "run fer the hills cause there ain't no god!" and panick. Nor do I keep my faith as a gratuitous method for dealing with my fellow carbon units on earth and for calming my spiritual nerves. That's not Biblical faith, that's psychology. Biblical Faith says not to be blown around by every doctrine but be grounded in what is said in the scriptures and keep on searching. The Bible says seek and you will find, it never says seek for a little while and then change your mind, it says seek. That means seek, by the minute, the hour, the day, the year, continously, relentlessly, zealously with total focus and commitment and never stop and you will find.If there is a God and this God is indeed the God of the Bible, I believe that he is able to see both the future and the past together and none of this has caught him off guard. But it does provide a good shaking out of those who call themselves his followers. I find what science is finding to be extremely facinating and supremely beneficial. I hope to expand my knowledge base exponentially by learning from the people here. The Bible said that in the last days knowledge will be increased as what we see happening today. The Bible did not say that in the last days knowledge will be increased and put an end to the Biblical truth as it proves the Bible nonsense. One of those statements is a prediction where the other is a fact. Only one could be given by God where the other could be given by anyone because to give a statement of fact about the future means you must be outside the boundries of time to be able to see it.When I said that I was looking to see if science and the Bible were telling the same story, first I need to make sure I know what story the Bible IS saying about the creation and then match it up to science. If they disagree, then I stand on the Bible and although I won't say science is wrong, I also won't say that our science is at it's zeinith, but that there are myriads of discoveries to find that might rock the scientific world to it's core.I'm not going to judge anyone here for what they believe and why, but I'm not going to discard my methodogy of discovery to see who's telling what story.

Lizard Breath,Your faith is not the issue here, it's cosmology.I admired what you said back in post #18, where your metaphor of 'tools for the job' crystallized what I believe about science and religion. I assert that if you're looking for God, science won't be much help. In addition, holy Scripture won't really help when the subject at hand is nuclear physics. Since then, however, you've changed your story, and now the Biblical account should be the same as the scientific one. "If they disagree," you state, "I stand on the Bible."Contrary to what Paul said, the wisdom of this world isn't folly. The fact that you're reading this on a computer is a testament to the utility of scientific progress. Everything we currently know about the universe is thanks to the tool box of science.So if you're going to use your faith in the Bible to look for answers concerning the age of the Sun, you must know of some applications of Scripture in astrophysics of which we're currently unaware. The rest of us stick with the tools that work.------------------
The dark nursery of evolution is very dark indeed.
Brad McFall