A young sun - a response

Here is a good introduction to helioseismologyhttp://solar-center.stanford.edu/...rror/english/engHA0.htmlThe neutrino problem is solved. And the oscillation of neutrino flavours is backed up by terrestrial observations from a nuclear reactor in Japan.The solar beryllium level also shows that much of it has been destroyed.The solar Lithium is approx. 1/200 of the primordial level.
The solar Beryllium is approx. 3/10 of the primordial level.This is all consistent with the rotational mixing and hydrodynamic (magnetohydrodynamic) transport mechanisms known to operate in the Sun.One final note, the concordance of theoretical solar models (sound speed profile with depth) and the observed solar internal sound speed profile is truly astounding. Agreement at the 0.1% level.Solar models cannot be that far wrong for such agreement.

I haven't the time right now, I have a class to teach on this very subject.I'll be back later to answer posts 14 and 15.Seems to be some misunderstandings about stars here.Bye

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)

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

Those emoticons remind me of my previous marriage.

1) The neutrinos are produced as part of the fusion process. They are electron neutrinos and are produced in several different energies depending upon which reaction they are from.H + H -> D + positron + neutrino neutrino energy ~ 0.263 MeVBe + electron -> Li + neutrino neutrino energy ~ 0.80 MeVB -> Be + positron + neutrino neutrino energy ~ 7.2 MeVN -> C + positron + neutrino neutrino energy ~ 0.71 MeVO -> N + positron + neutrino neutrino energy ~ 1.0 MeVThe original detectors only could detect the 7.2 MeV neutrinos. Unfortunately this is a rare reaction.But newer experiments (and ones planned) are sensitive to the other reactions which also contribute many more neutrinos.2) Off the top of my head i cannot remember the neutrinos produced in Helium burning but they would have characteristic energies just as the hydrogen burning ones do.3) The flavour change has been directly observed at the Sudbury Neutrino Observatory because it is sensitive to all neutrinos via different reactions. Also in Japan the neutrino flux from a nuclear reactor has been observed to do this.4) The determining factor is distance. Neutrinos interact so weakly with matter there is nothing you could 'fluoresce' as you put it.5) Neutrino's are produced by nuclear reactors but tey fly off in all directions. Remember they interact so weakly you cannot focus them or anything.6) Neutrino's have NO charge. (Hence the term NEUTrino as in neutral)7) Ha Ha

Well neutrinos are important in some astrophysical processes. Though they hardly interact with normal matter (trillions going through your body every second) if matter is very dense that can change.In a star the neutrinos are basically an energy sink, their energy escapes the star, end of story.But in the core of a massive star you can reach a situation where the density gets high enough towards the end of the stars lifetime where the neutrinos are more easily absorbed. This energy is thus not allowed to escape and stays in the stellar core.Many nuclear processes then can occur which normally do not. This is important in the stages just before the star goes supernova.Also neutrinos, since we now know they have mass, are a contributor to the so called 'dark matter'. However it seems they are not the largest constituent of the dark matter. Neutrinos fall into what is called the Warm Dark Matter component which it seems is not as important as the Cold Dark Matter which at present is not known what it is composed of. (maybe WIMPS - Weakly Interacting Massive Particles).

No! A 100 year old (or 1000) Sun is quite a different object. Also what do you define as the year zero?But proabably more relevant is the fact you claim to have studied the Bible for 58 years and yet are still interpreting it completely in a literal manner.Are those hares still ruminants to you? Last time I checked they don't chew the cud as expressed in the Bible.What part of literal being wrong don't you get?Also by one of your previous posts you just flat out imply no knowledge can trump you Biblical literalism. Why even be on a forum such as this asking questions or commenting.Do you function in daily life on such a base, gullible level. I mean people who accept the Bible hook, line and sinker would not (I hope) accept other things in their life so readily and with so little evidence. (Actually evidence to the counter)Also why are the Biblical literalists so much a minority in the Christian World?They seem to be confined to the North American Bible Cults (Baptists, Nazarenes, Adventists, Pentecostalists etc.) but not the large Christian denominations (Catholic, Orthodox, Anglican). The other common source of literalism also seems to be the poorly educated. Where Christianity has been introduced in the 3rd World initially Biblical literalism has a strong hold but has the population becomes better educated it's hold lapses and more mainstream Christian ideology takes over? I wonder why this is? The conclusion one can draw is that education and literalism seem mutually exclusive of one another.

I don't understand your question.What do you mean by 'have to show age'?That makes no sense to me - please elaborate.

OK now I see what you are getting at.First off, 7000 years old from a starting point you define as what?If you mean as it looks today, and then age it 7000 years nothing much would change.If you start it in a 'pristine' state and age it 7000 years then NO it would look different than it does.In other words to say it is 7000 years old you have to say it was created with an appearance of age. A terrible philosophy, not only for science but for religion too.

That is why I put the caveat question of '7000 years from what?'.Forgetting about gravitational contraction, it could work by fusion on just hydrogen.And yes it could be very young and gravitational contraction would provide the energy.However in that case it would be different than observed. Even forgetting about abundances and such it would have different helioseismological properties. It's internal sound speed profile would be different than observed. It would be homogeneous at that stage as opposed to the known structure today.

NO NO NOYou are quoting something wrong.Look carefully at the numbers on the website.