Solid Surface Model of the Sun?
3 Aug 2005 22:20:23 UTC
Topic 189659
(moderation:
The website The Surface Of The Sun has compiled some absolutely stunning imagery of the Sun, from the YOHKOH, SOHO and TRACE solar observation programs, along with spectral analysis from the SERTS program.
Perhaps more stunning than the imagery is the proposed solid-surface model of a star. If you thought the Sun was just a big ball of hydrogen, the author (Michael Mozina) provides compelling evidence for thinking otherwise.
I can't think of a better place to get good opinions than the E@H science message board forum, and so I'd like to invite folks to participate in an impromptu survey. For your convenience, I'll post below, “I think the solid surface model may be valid,” and “I do not think the solid surface model is valid,” so you can click the “+” to rate either post as you see fit. And if you have the time to post additional comments or thoughts, by all means, please feel free!
Solid Surface Model of the Sun?
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I THINK THE SOLID SURFACE MODEL OF A STAR MAY BE VALID
I DO NOT THINK THE SOLID
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I DO NOT THINK THE SOLID SURFACE MODEL OF A STAR IS VALID
Entertaining but wrong in so
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Entertaining but wrong in so many ways.
The core of the Sun is much hotter than the surface about 10^7 K vs 6*10^3 K.
Totally ignores the results of helioseismology.
solar interior
Iron makes up about .14% of the Solar mass.
solar composition
Plasma’s are highly conductive the presence/absence of Iron will be insignificant.
Any positrons created in the fusion processes are immediately annihilated. Most of the energy crated in the Sun’s core is initially transported toward the surface by photons (a lot of it escapes as neutrinos).
Hi, Mark! Thanks for the
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Hi, Mark!
Thanks for the links.
I was wondering what you meant by the temperature difference between the core and the surface. Where does the core temp data come from – is it the CNO reaction temp? How does this affect either gas or solid surface models?
Totally ignores it, and then some! Mozina actually points to data and interprets the fracture-like line that forms between distant points on the sun's surface, in a spectacular set of images, as resulting from literal sunquakes. Neither an expert in helioseismology, nor fluid mechanics, I am still at a loss as to how these “structures” (and many others pointed out by Mozina) can possibly arise from just gas/plasma.
Also, how does the quite uniform distribution of p-waves (ref: 'solar interior' link, above. Note same image on Wikipedia's Helioseismology page) help us to measure composition?
Is is fair to say that elemental composition has been arrived at using analysis of spectral absorption lines? How does this work for determining relative abundance and distribution? Mozina cites the latest barrage of technological instrumentation when making a case for newer distributions and greater relative amounts of various elements. He points out that the newer instruments use analysis of spectral emission lines combined with Doppler to give the 'breathtaking' 3D images, showing where specific elements actually are, but I don't understand why there should be a discrepancy between emission and absorption techniques for determining relative abundance...
RE: Where does the core
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Models of stellar interiors combine several component theories. One part is how readily various nuclear reactions occur at different temperatures and densities. Another is how the reaction products interact with the stellar media. Models of how the heat energy flows from the core to the stellar surface describe the bulk of the star. Matching the component theories with the temperature of the surface, composition and size of the star gives us a good idea of what we could expect to find if we could directly sample the interior of a star. Helioseismology has confirmed the broad outline and refined some of the details of the model of the Sun.
Yes
The amout of the each atomic type determines the strength of it spectral lines.
It is important to note that outer layer of the Sun is very well mixed by convection. This covective layer actually makes up most of the Sun's interior. It is extremely unlikely that there is any hidden reserve of Iron or any other element.
IMHO it is the mixing due to convection that supplies the likelist explaination for the Sun's differential rotation. Mixing drives angular momentum distribution towards uniformity. Viscousity drives the angular velocity towards uniformity.
The gas models don't appear
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The gas models don't appear to be in as desperate straights as Mozina says. The structures and features seen in the various images, as spectacular as they are, can be explained with the behavior of plasmas constrained in strong electromagnetic and gravitational fields. At such extreme temperatures in, and at the base of the photosphere (~6000 degrees Kelvin), molecules cannot even form, much less solids.
I learned that Helioseismology does help us to determine element abundances, by using the data to calibrate theoretical models, and by a direct inversion of frequencies in conjunction with equations of state, equations of stellar structure, reaction rate equations, and opacity, to relate abundance with seismic parameters. (Ref: link provided by Mozina to a most authoritative and informative site, Dr. Alexander G. Kosovichev of Stanford, specifically referring to the “Helioseismic Measurements of Element Abundances” paper.)
Regarding spectral absorption lines, Wikipedia has nice high resolution image of the Solar Spectrum across the visible range from 4000 to 7000 angstroms, that came from the Kitt Peak National Observatory.
Thanks for your responses, Mark. It looks to me like your initial characterization as “entertaining” was accurate.
Would Mozina's work fare better if the references to a “solid” surface were changed to something like a “uniquely composed plasma shell/envelope”?
RE: Would Mozina's work
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IMHO It would need more than that.
Interesting links, thanks for posting them.
Regarding the question of
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Regarding the question of solar coronal heating, what portion of the temperature increase can be attributed to changes in the particle density and changes to the rate of change of entropy, between conditions in the photosphere and those in the corona?
If this is a system where the entropy S(E) is a function of its energy E, such that temperature T is given by 1/T = dS/dE, then isn't the coronal heating a natural consequence of a decrease in entropy, from one of disorder in the photosphere, to one of order in the corona? Since the 2nd law of thermodynamics says that any process results in either no change, or a net increase, in the entropy of the universe, and assuming that dE is constant between the photosphere and the corona, then the only way for dS to change from disorder to order is if T increases proportionally. Does this any make sense?
RE: The website The Surface
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Just to add some fuel to the fire..... :)
The finding of an unexpectedly large source of energy from repulsive interactions between neutrons in the 2,850 known nuclides has challenged the assumption that H-fusion is the main source of energy that powers the Sun and other stars.
http://arxiv.org/abs/astro-ph/0511379
FYI, during sunspot activity, plasmas with temperatures that would support solids have been seen flowing up through the surface of the photosphere. This suggests that the umbra region underneath the penumbral filaments "could" support temperatures that are condusive to the formation of solids.
Dr. Charles Bruce documented a number of solar phenomenon that are directly attributeable to electrical discharges in the solar atmosphere, and he also cited sunspot temperature evidence to support his theories.
It seems to be a natural consequence of our points of view to assume that the whole of space is filled with electrons and flying electric ions of all kinds. - Kristian Birkeland
Wow!! Hi, Michael! Welcome
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Wow!! Hi, Michael! Welcome to Einstein@Home! That's some awfully good fuel. It makes sense to me, although I'm not a physicist. It's exciting to think that the nearest pulsar is the Sun. Definitely looking forward to comments from others!