All About the Sun
You about Tim? I think that Scotts paper was actually aimed at you in person, so would appreciate your input the most. With or without your usual lightbulb heading to your post, not fussed either way.
My posts shed light in the eternal darkness, so naturally I just love the lightbulb.
Yes, Scott's remarks are aimed at me, and maybe someday I will be industrious enough to make a detailed response. As for his criticisms of helioseismology, they are simply stupid.
The basic mathematical technique is exactly the same as used by earthbound seismologists to map out the interior of the Earth, by atmospheric scientists to map the layers of Earth's atmosphere, by engineers to study the internal structure of sold bodies, and by medical scientists to make holographic images of organs. It's called
tomography, and it is heavily verified by extensive practical experience, all dismissed by Scott as if it does not exist. His willingness to either ignorantly dismiss that kind of well verified science, or deliberately misrepresent it, does not inspire confidence as far as I am concerned. Indeed, helioseismology works so well that it allows us to see sunspots while they are still on the other side of the sun, before they rotate into view (i.e.,
AR9393, 12 April 2001). That's a pretty good trick to pull off with a "fictional" method.
Now, before you hijacked the thread there was a legitimate query:
Does anyone know how long a change in the core of the sun take to be observable, example sunspots etc.
The speed of sound inside the sun varies with depth and is a function of temperature, pressure & density. In general, on the order of 10 km/sec should be a good number. With a radius of about 695,000 km, that speed would get an acoustic wave from the core to the surface in about 19.3 hours. I am unsure of the precise numbers, but that's a reasonable average.
But sunspots, and all the other magnetic phenomena, are mostly surface affairs and are independent of what goes on in the core, at least over relatively short time scales. Of course, over long time scales, if the sun were to shut off, for example, that would obviously affect sunspots, and everything else, once the effect had reached the surface.
The first roughly 3/4 of the solar radius represents the
radiative zone where there is no convection, and energy transport is by photons, which as you already know, move along quite slowly because of the enormous density and small mean free path. It takes anywhere from 100,000 to 1,000,000 years for a photon to get from the core to the surface, depending on which source you get the number from. The reason for the large discrepancy is that the time is sensitive to parameters that are not well known for the internal structure of the sun.
But the outer 1/4 or so of a solar radius represents the
convective zone, where convective motion dominates energy transfer. The base of the convective zone is called the
tachocline, and that is where the dynamo process inside the sun generates the solar magnetic field, which in turn causes sunspots. Hence, they are determined by the physics of the convective zone and not much dependent on anything going on in the sun deeper than that. Sunspots themselves are about 2500 km in depth. That's about twice the depth of the
photosphere of the sun, the region which emits the light that we see.
For anyone seriously interested in the serious science of the sun, as opposed to the fictional electric explanations, I recommend the book
Solar Astrophysics; Peter V. Foukal, Wiley-VCH, 2004. For those foolishly devoted to the electrical star paradigm, I suggest the simple courtesy of starting your own thread devoted to the topic, as opposed to the time honored paradigm of thread hijacking.
But, of course, I could be biased.
