In forming the stellar structure equations (exploiting the assumed spherical symmetry), one considers the matter density \rho(r), temperature T(r), total pressure (matter plus radiation) P(r), luminosity l(r), and energy generation rate per unit mass \epsilon(r) in a spherical shell of a thickness \mbox{d}r at a distance r from the center of the star. [maskurl=]The star is assumed to be in local thermodynamic equilibrium [/maskurl](LTE) so the temperature is identical for matter and photons.
It is useful to distinguish between global and local thermodynamic equilibrium. In thermodynamics, exchanges within a system and between the system and the outside are controlled by intensive parameters. As an example, temperature controls heat exchanges. Global thermodynamic equilibrium (GTE) means that those intensive parameters are homogeneous throughout the whole system, while local thermodynamic equilibrium (LTE) means that those intensive parameters are varying in space and time, but are varying so slowly that, for any point, one can assume thermodynamic equilibrium in some neighborhood about that point.
In thermodynamics, a thermodynamic system is in thermodynamic equilibrium when it is in thermal equilibrium, mechanical equilibrium, radiative equilibrium, and chemical equilibrium. Equilibrium means a state of balance. In a state of thermodynamic equilibrium, there areno net flows of matter or of energy, no phase changes, and no unbalanced potentials (or driving forces), within the system.A system that is in thermodynamic equilibrium experiences no changes when it is isolated from its surroundings.
CC:
Right. To find a thermodynamic equilibrium, you have to head out to Pluto, or beyond. At that distance, the solar wind is thin, and the photons from the Sun are meager. So you could say that the heliosphere as a whole is in equilibrium with the interstellar medium, with little-to-no exchange across the heliopause. But to say that the Sun is in thermodynamic equilibrium with the interplanetary medium denies that there is a robust outflow, of particles and photons. The inner solar system would be a cold, dark place if the Sun was actually in equilibrium with its surroundings.
Well, I get the impression that the sun is all of a LTE, and the heliosphere is not part of the LTE. Is there some disagreement about what the sun's LTE is? Or am I misunderstanding what the wiki says.?
CharlesChandler
Re: The General Theory of Stellar Metamorphosis
Is there any energy exchange between the Sun and the interplanetary medium, especially the inner solar system?
Yes.
This means that the Sun is not at equilibrium with the interplanetary medium, or there wouldn't be any energy exchange.
Is there any energy exchange between the heliosphere and the interstellar medium?
It doesn't look like there is much. Therefore, the heliosphere, taken as a whole, is in equilibrium with the interstellar medium.
If you try to think of this in complicated terms, you won't understand it.
JeffreyW
Re: The General Theory of Stellar Metamorphosis
Sparky wrote:
Well, I get the impression that the sun is all of a LTE, and the heliosphere is not part of the LTE. Is there some disagreement about what the sun's LTE is? Or am I misunderstanding what the wiki says.?
All LTE means is Local Thermodynamic Equilibrium.
In other words the Sun in their models:
1. Does not have solar wind. (It does)
2. Does not radiate (it does)
3. Is the temperature of outer space (its not)
4. Does not convect anywhere (it does)
5. Does not experience plasma recombination anywhere. (it does)
Basically their model completely ignores reality so that the math works. Their model is pseudoscience. I have learned the hard way that mathematical models are fake science. If you have to ignore basic thermodynamic principles to make the models work, you're not doing science.
JeffreyW
Re: The General Theory of Stellar Metamorphosis
CharlesChandler wrote: Is there any energy exchange between the Sun and the interplanetary medium, especially the inner solar system?
Yes.
This means that the Sun is not at equilibrium with the interplanetary medium, or there wouldn't be any energy exchange.
Is there any energy exchange between the heliosphere and the interstellar medium?
It doesn't look like there is much. Therefore, the heliosphere, taken as a whole, is in equilibrium with the interstellar medium.
If you try to think of this in complicated terms, you won't understand it.
Yes, it is very simple. It doesn't take a PhD to understand this stuff.
Sparky
Re: The General Theory of Stellar Metamorphosis
thermal equilibrium - the amount of energy generated equals the amount radiated away
It is useful to distinguish between global and local thermodynamic equilibrium. In thermodynamics, exchanges within a system and between the system and the outside are controlled by intensive parameters. As an example, temperature controls heat exchanges. Global thermodynamic equilibrium (GTE) means that those intensive parameters are homogeneous throughout the whole system, while local thermodynamic equilibrium (LTE) means that those intensive parameters are varying in space and time, but are varying so slowly that, for any point, one can assume thermodynamic equilibrium in some neighborhood about that point.
I still do not see That LTE extends beyond the sun. Are you guys making up your own definitions?
CharlesChandler
Re: The General Theory of Stellar Metamorphosis
Sparky wrote:
thermal equilibrium - the amount of energy generated equals the amount radiated away
I still do not see That LTE extends beyond the sun. Are you guys making up your own definitions?
You got that definition from a mainstream astronomy website. Here's how Wikipedia defines thermal equilibrium:
Two physical systems are in thermal equilibrium if no heat flows between them when they are connected by a path permeable to heat. Thermal equilibrium obeys the Zeroth Law of Thermodynamics. A system is said to be in thermal equilibrium with itself if the temperature within the system is spatially and temporally uniform.
Wikipedia isn't always right, but as concerns simple engineering stuff like that, there's no mistaking the correct definition. Astronomers redefined thermal equilibrium for their purposes, from a system in which there are no heat exchanges, to a system in which the amount of heat that is exchanged is steady. That way, they get to use scientific jargon in sentences in a way that fools people who give them the benefit of the doubt. But there is a difference between "no heat flow" and "constant heat flow". The first is a thermal equilibrium in which no work is done, while the second is a throttled energy conversion that steadily does work.
JeffreyW
Re: The General Theory of Stellar Metamorphosis
CharlesChandler wrote: Astronomers redefined thermal equilibrium for their purposes, from a system in which there are no heat exchanges, to a system in which the amount of heat that is exchanged is steady. That way, they get to use scientific jargon in sentences in a way that fools people who give them the benefit of the doubt. But there is a difference between "no heat flow" and "constant heat flow". The first is a thermal equilibrium in which no work is done, while the second is a throttled energy conversion that steadily does work.
That's not the only way astronomers have redefined things, they have any element heavier than hydrogen/helium as a "metal". This is also to suit their needs to make stuff up:
In astronomy, a "metal" is any element other than hydrogen, helium or lithium. This distinction is significant because hydrogen and helium (together with trace amounts of lithium) are the only elements that occur naturally without the nuclear fusion activity of stars. Thus, the metallicity of a galaxy or other object is an indication of past stellar activity.
By re-defining things they cause huge misdirection and fuel the confusion. Their problems are basic ones. I'd consider defining oxygen, nitrogen and argon as metals to be a Middle School mistake.
Sparky
Re: The General Theory of Stellar Metamorphosis
CC
Wikipedia isn't always right, but as concerns simple engineering stuff like that, there's no mistaking the correct definition.
Well, there seems to be just that! LTE is what in dispute, and until we get a clear definition of that, in relation to the sun, people are looking at it with their own bias.
I do not see LTE as anything outside of the sun system.
And, jeffrey. where is the documentation that supports your contention that Standard solar model has the Sun being in thermodynamic equilibrium with its environment.
It can't be! LTE does not need the heliosphere as part of it's sun's Local environment.
JeffreyW
Re: The General Theory of Stellar Metamorphosis
Sparky wrote: CC
Wikipedia isn't always right, but as concerns simple engineering stuff like that, there's no mistaking the correct definition.
Well, there seems to be just that! LTE is what in dispute, and until we get a clear definition of that, in relation to the sun, people are looking at it with their own bias.
I do not see LTE as anything outside of the sun system.
And, jeffrey. where is the documentation that supports your contention that Standard solar model has the Sun being in thermodynamic equilibrium with its environment.
It can't be! LTE does not need the heliosphere as part of it's sun's Local environment.
That is what LTE is! In the SSM equations it is assumed that the Sun is in LTE! Or Local Thermodynamic equilibrium.
In forming the stellar structure equations (exploiting the assumed spherical symmetry), one considers the matter density \rho(r), temperature T(r), total pressure (matter plus radiation) P(r), luminosity l(r), and energy generation rate per unit mass \epsilon(r) in a spherical shell of a thickness \mbox{d}r at a distance r from the center of the star. The star is assumed to be in local thermodynamic equilibrium (LTE) so the temperature is identical for matter and photons.
The standard solar model (SSM) is a mathematical treatment of the Sun as a spherical ball of gas (in varying states of ionisation, with the hydrogen in the deep interior being a completely ionised plasma). This model, technically the spherically symmetric quasi-static model of a star, has stellar structure described by several differential equations derived from basic physical principles.
They are not rooted in basic physical principles. That is outright lie! They IGNORE basic physical principles to make the math work how they want! In other words, the SSM isn't even a theory of stellar evolution, its just a bunch of math equations that have no real meaning.
Sparky
Re: The General Theory of Stellar Metamorphosis
@ http://www.mps.mpg.de/2816154/ROMIC Introduce significantly more physical realism into the modelling, in a first step, by employing state-of-the-art 3D radiation MHD simulations of the solar atmosphere, in particular MURaM simulations, to compute the spectrum of solar regions with different amounts of magnetic flux. The available simulations have local thermodynamic equilibrium (LTE) radiative transfer and allow the spectrum to be computed down to 300 nm. Further develop the MHD simulations. The most important extension is in height, so that the models also cover the solar chromosphere, where the cores of the stronger spectral lines in the UV spectrum (and some in the visible and infrared) are formed. In order to do so we need to take non-LTE into account in the radiative energy transport in the simulation. This extension of the model will significantly improve the critical UV fluxes below 300 nm resulting from the MHD simulations.
Can not find a direct reference to LTE being the sun only, but this suggests that.
To me this says that LTE is only the sun. That makes more sense than taking in the whole heliosphere. LtE is considered to be the sun's status. But it is a misuse of LTE to expand the environment to the heliopause. So, your conclusion that the sun needs to be in equilibrium with the entire heliosphere is not correct. You need to modify your logical disproof.
CharlesChandler
Re: The General Theory of Stellar Metamorphosis
No he doesn't. In the standard model, the heat is generated in the core, and radiates outward from there. So the core is not in equilibrium with the radiative zone, which is not in equilibrium with the convective zone, which is not in equilibrium with the solar atmosphere...
To find a thermal equilibrium, you have to find some point at which there is no longer any heat transfer.
As best as I can tell, that would be the heliopause.
Sparky
Re: The General Theory of Stellar Metamorphosis
I don't know what the standard model guys consider LTE to be. It is not as easy to figure and define as you say. I have never worked at thermodynamics, so I have to go by what documentation I have seen. The solar system is a huge place to have any kind of equilibrium. Local thermodynamic equilibrium? How? What is so Local about the solar system?
jacmac
Re: The General Theory of Stellar Metamorphosis
I agree with Sparkey.
Local means about a POINT. the whole sun would be GLOBAL.
We need to use the mainstream terms correctly to argue against the main stream.
IMHO. Jack
JeffreyW
Re: The General Theory of Stellar Metamorphosis
I am reading this paper right now and I notice quite a few things right off the bat.
David R. Soderblom wrote: All of this means that a star's age cannot be measured, it can only be estimated or inferred. This is underscored by the fact that we have exactly one stellar age that is both precise and accurate, and that, of course, is for the Sun. But the Sun itself does not reveal its age; it is only because we can study solar system material in the laboratory that we can limit the Sun's age. We can do that for no other star.
David R. Soderblom wrote: a star's age cannot be measured, it can only be estimated or inferred
In stellar metamorphosis the star can have its parts measured, like for instance radioactive decay rates can be used to measure the contents of the crust of the Earth. This can set the limit for how young it can be. For instance the Earth (a black dwarf star) cannot be 5,000,000 years old if portions of the crust are 3 billion years old. It has to be at least 3 billion years old.
David R. Soderblom wrote: This is underscored by the fact that we have exactly one stellar age that is both precise and accurate, and that, of course, is for the Sun.
This is the main root assumption getting in the way again. It is believed that stars and planets are mutually exclusive, they are not though. A planet is an ancient star and a star is a new planet. They are actually the same objects only in different stages to their evolution. Therefore, we have at least one star that we can determine the limit for how young it can be, the Earth itself.
David R. Soderblom wrote: But the Sun itself does not reveal its age; it is only because we can study solar system material in the laboratory that we can limit the Sun's age.
Yes, we can limit the Sun's age, meaning it can not be older than the Earth. This is a direct result of the general theory of stellar metamorphosis. Stars with compositions of material with higher entropy (plasma/gas) cannot be older than stars with material of mostly lower entropy (solids/liquids). Systems that are not isolated (stars) can spontaneously evolve towards levels of lower entropy (less organization to more organization as a consequence of work done), and they do, life is a consequence of stellar evolution.
In the General Theory of Stellar Metamorphosis we can firmly place material in the laboratory as well. We don't even need to make assumptions as to the origins of material in outer space, which could have origins from outside our system.
David R. Soderblom wrote: We can do that for no other star
Yes, we can.
We are standing on one and even have rovers on Mars, which is an even older black dwarf than Earth.
CharlesChandler
Re: The General Theory of Stellar Metamorphosis
JeffreyW wrote: Yes, we can limit the Sun's age, meaning it can not be older than the Earth.
If both the Sun and Earth were the same size when they first formed, and if they both evolved at the same rate, and if the Earth is (obviously) further along in the process, then the Earth is older than the Sun. I agree with this, but I just wanted to point out the assumptions. If a lot more matter condensed into the Sun than the Earth, then perhaps the Sun is taking longer to evolve, assuming that the rate of evolution is dictated by mass loss to the solar winds. If that's the case, the Sun is older than the Earth. So I think that it's a mistake to assume that all stars were created equal.
