Stellar Remnants

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origin

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harrycostas":3vcqu3f0 said:
G'day origin

I'm fully awear of the link that I posted.

and yet again rather then talking about the subject you have lead yourself in the same position of being a negative critic.

Is there something you wish to offer?

As for being a laughing stock, mate you are off this planet.

If you are fully aware of the link you posted, why oh why would you post it? Try to understand from a readers point of view; your methodology makes no sense. You are essentially saying - "I think position 'A' is wrong and position 'B' is right, so to prove my point here is a link supporting position 'A'. This seems kind of funny don't you think?
 
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origin

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michaelmozina":2zabqrlh said:
Mostly he spends his time posting personal insults.

Now, now I only insult people that state goofy conjecture as fact - you know like saying there is photographic evidence of volcanos on the sun (I just love that one).

It's unfortunate, but it's typical of this 'style'. Don't take him seriously, none of the rest of us do.

If by "none of the rest of us" you mean the 'the suns just a big iron ball' crowd - I'll take that as a compliment.
 
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michaelmozina

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origin":1qx6j9g5 said:
Now, now I only insult people that state goofy conjecture as fact -

Only mainstream astronomers state conjecture as "fact". I don't know any non standard solar theory proponents, or non standard cosmology proponents that are not aware that their opinions are "conjecture".

you know like saying there is photographic evidence of volcanos on the sun (I just love that one).

Well, there is certainly photographic evidence that can be *interpreted* that way. Of course you are "factually certain" of your position. Pots, kettles, etc.

If by "none of the rest of us" you mean the 'the suns just a big iron ball' crowd - I'll take that as a compliment.

It doesn't seem to be related to any specific theory or topic. The only common denominator is that it must relate to a belief that you personally disagree with. Whereas Yevaud and UMFButler (and most everyone else) focuses on the 'science' and scientific arguments during debate, you tend to go "personal". It's actually a matter of your personal debate "style", not the specific "topic" as far as I can tell.
 
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MeteorWayne

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To all:

Please lete's stick to the topic of stellar remnants,

Thanx

Mod Wayne
 
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Astro_Robert

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for a short while, but decided to join in on this one.

Although I do agree with most of you that the arguement for SNR 'rejuvenation' has been poorly presented and by the original author, I have actually heard of such things before.

Probably 5-10 years ago, I read an article by some astronmer (not certain who or of what repute) that claimed that our sun could have a stellar remnant of some sort at its core. The idea in the article was to explain emiisions from our sun that do not agree with observations. If i recall correctly, the author had been trying to propose an alternative to the idea that neutrinos can morph. His theory was that a stellar remnant at the core could have accounted for some of the reduced neutrino detections. I do not recall the article going into detail how such a proposed star would lie on the mainsequence or behave as one that did.

However, in the event such an object could form whose total mass is approximately 1 solar mass, then it would be below the Chandrasekar limit, and thus avoid being promptly destroyed. As to how a cloud of any sort would condense or rain down upoon a presumably hot remnant without a nova event and form this object, was not discussed in that article.

I will look around to see if I can find that article, but it was some years off. I only remember it because it proposed an intereseting concept. My best recollection was that this article was in the popular press, not in a peer reviewed science publication. It is possible it that what I read was a reference to a peer reviewed article, I simply do not recall authorship details.


Astro
 
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michaelmozina

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http://www.hulu.com/watch/92290/the-uni ... s-p1-so-i0

http://www.spaceref.com/news/viewpr.html?pid=17308

I think near the end of that solar movie they discuss the fact that all elements heavier than iron come from the supernova process. In addition, there seems to be some evidence that there was a supernova somewhere in our vicinity that still drops dust grains into the Earth's atmosphere. The idea that news suns form from supernova events is not all that controversial as I understand it, but perhaps someone could clarify?
 
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origin

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michaelmozina":3u5pvak2 said:
The idea that news suns form from supernova events is not all that controversial as I understand it, but perhaps someone could clarify?

Star formation resulting from a supernova event is not controversial. As a matter of fact Harry had a link that discussed this phenomena - http://arxiv.org/abs/0907.3667. Essentially a pressure wave from a super nova can initiate the gravitational collapse of a molecular cloud resulting in the formation of a star.

What is controversial - actually it is in the realm wild conjecture - is that the actual neutron star or black hole could become a main sequence type star by the accretion of material. There is just is no mechanism that would allow that. Material would just spiral into the stellar remnant and be incorporated into it, resulting in a larger remnant.
 
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MeteorWayne

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I was about to clarify that point origin, but you beat me to it. Thanx.
 
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michaelmozina

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origin":5eokt9w2 said:
What is controversial - actually it is in the realm wild conjecture - is that the actual neutron star or black hole could become a main sequence type star by the accretion of material. There is just is no mechanism that would allow that. Material would just spiral into the stellar remnant and be incorporated into it, resulting in a larger remnant.

Well, I would have to agree with you on the notion of a 'black hole' although I don't believe anything achieves an infinite density, but why would you assume hydrogen and helium would be "incorporated into" a neutron star in a way that precluded it from generating fusions reactions and such? I can see how you might believe it would all eventually fuse to iron, but it seems as though such a process might take time.
 
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harrycostas

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G'day from the land of ozzzzzz

I just finished reading a number of papers on supernova remnants. There is no paper that states that a solar envelope cannot form on any compact core such as Neutron star, quark star or a so called black hole (without a singularity). In actual fact it forms a gravity sink that ejected matter falls back forming an envelope or a halo.

Further to that discussion the dynamo that exists in stars is quite similar, particularly the long life stars. A compact core exists having various compositions of matter, ranging from a Neutron/Proton soup to Neutron/quark soup or quark/Nutrino soup. The intrinsic property of such matter produces a spin in the core that ejects matter in many cases to the solar envelope and in some cases deep into space.
You can refer to wiki
Dirac spinor
Top quark condensate
 
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silylene

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harrycostas":3dcdzd4t said:
G'day from the land of ozzzzzz

I just finished reading a number of papers on supernova remnants. There is no paper that states that a solar envelope cannot form on any compact core such as Neutron star, quark star or a so called black hole (without a singularity). In actual fact it forms a gravity sink that ejected matter falls back forming an envelope or a halo............

Maybe no paper states this because the idea of reforming a solar envelope is not the subject or their paper, or becuase the idea is so without basis that it didn't even merit discussion.
 
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ramparts

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harrycostas":f6vu1j7g said:
G'day from the land of ozzzzzz

I just finished reading a number of papers on supernova remnants. There is no paper that states that a solar envelope cannot form on any compact core such as Neutron star, quark star or a so called black hole (without a singularity). In actual fact it forms a gravity sink that ejected matter falls back forming an envelope or a halo.

Further to that discussion the dynamo that exists in stars is quite similar, particularly the long life stars. A compact core exists having various compositions of matter, ranging from a Neutron/Proton soup to Neutron/quark soup or quark/Nutrino soup. The intrinsic property of such matter produces a spin in the core that ejects matter in many cases to the solar envelope and in some cases deep into space.
You can refer to wiki
Dirac spinor
Top quark condensate

Harry - If you research the literature on rabbit biology, you will not find a single paper stating that bunnies can't fly.

As silylene said, of course no paper says that, because it's not an idea that anyone takes seriously. There are too many flaws and too few arguments in favor to warrant any papers refuting it. Meanwhile, we've explained (see my post a page back) how the paper you posted actually agrees with what the rest of the board is saying. But you keep saying there's this "gravity sink" around the compact object which funnels all the gas back onto that object, forming a star - and you even claim that this is what astronomers today believe! But you still haven't shown us a paper saying that.
 
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origin

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michaelmozina":94oppq35 said:
Well, I would have to agree with you on the notion of a 'black hole' although I don't believe anything achieves an infinite density, but why would you assume hydrogen and helium would be "incorporated into" a neutron star in a way that precluded it from generating fusions reactions and such?

Let's just look at a neutron star then.

Fusion reactions require a combination of high pressure and high temperature (of course at high enough temperatures the pressure is not as important). If we imagine 2 hydrogen atoms at rest at the edge of the gravitational well of a neutron star they would accelerate towards it until they actually 'hit' the surface and were absorded into the neutron mass - remember a neutron star is little more than an unimaginable large atomic nucleus.

Now this idealized scenario is unlikely to happen, what actually happens is that matter forms an accretion disk around the neutron star. The matter in this accretion disk spirals into the star. The inner area of the accretion disk reachs very high temperatures indeed - this is evident from the massive amounts of high energy EM from neutron stars. So I would think that it is very possible that there is some fusing of elements in the accretion disk. But this scenario is nothing like a main sequence types star and this scenario does not lend itself to ever create an actual main sequece type star.

I can see how you might believe it would all eventually fuse to iron, but it seems as though such a process might take time.

What elements are created in the accretion disk (if indeed any are) will be a moot point when they are finally pulled into the neutron star and become 'one with the core'. But again, there is no possible mechanism (that I can envision anyway) that could result in a 'normal' star forming around a neutron star.
 
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origin

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harrycostas":294ko7dr said:
G'day from the land of ozzzzzz
In actual fact it forms a gravity sink that ejected matter falls back forming an envelope or a halo.

Really? If that is a fact, please supply some evidence.

Further to that discussion the dynamo that exists in stars is quite similar, particularly the long life stars. A compact core exists having various compositions of matter, ranging from a Neutron/Proton soup to Neutron/quark soup or quark/Nutrino soup. The intrinsic property of such matter produces a spin in the core that ejects matter in many cases to the solar envelope and in some cases deep into space.

Really? So a "Neutron/Proton soup to Neutron/quark soup or quark/Nutrino soup" exists in long life stars? It does? How does this information come to you, in dreams?

So an intrinsic property of a your "Neutron/Proton soup to Neutron/quark soup or quark/Nutrino soup" is that it produces spin and ejects matter? Where in the name of all that is holy, do you come up with this stuff?

Dirac spinor
Top quark condensate

Please enlighten me how either of these topics relate in any way, shape, or form to your point (watever it is).
 
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UFmbutler

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harrycostas":2ozwbwct said:
G'day from the land of ozzzzzz

I just finished reading a number of papers on supernova remnants. There is no paper that states that a solar envelope cannot form on any compact core such as Neutron star, quark star or a so called black hole (without a singularity). In actual fact it forms a gravity sink that ejected matter falls back forming an envelope or a halo.

Further to that discussion the dynamo that exists in stars is quite similar, particularly the long life stars. A compact core exists having various compositions of matter, ranging from a Neutron/Proton soup to Neutron/quark soup or quark/Nutrino soup. The intrinsic property of such matter produces a spin in the core that ejects matter in many cases to the solar envelope and in some cases deep into space.
You can refer to wiki
Dirac spinor
Top quark condensate


Maybe logical argument doesn't get through to you. Allow me to try to put this into concepts you might understand better. I just finished reading a number of papers on stellar evolution, and discovered that it is impossible for a star to form on top of exotic forms of matter. This must therefore be because there are scary dinosaurs lurking in those black holes that scare the accreting gas away. I came to this conclusion because none of the papers I read said there were no dinosaurs inside stellar remnants.

You can refer to wiki
Velociraptors
Scary


In all seriousness, you aren't going to convince anybody by wildly hypothesizing using scientific words that have no relation to the topic. What do quarks have to do with anything? Quark stars are still a theoretical structure. Do you know what a dynamo is?

Explain how a neutron star/black hole core can undergo hydrogen fusion and begin its main sequence lifetime. I know no papers say it can't, but as I demonstrated that is not a valid form of argument. You have to show yourself or refer us to a paper that demonstrates this is possible. You still haven't addressed why black holes at the centers of active galaxies never turn into 10^9 solar mass stars.
 
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michaelmozina

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origin":hgp8v9o6 said:
Let's just look at a neutron star then.

Fusion reactions require a combination of high pressure and high temperature (of course at high enough temperatures the pressure is not as important). If we imagine 2 hydrogen atoms at rest at the edge of the gravitational well of a neutron star they would accelerate towards it until they actually 'hit' the surface and were absorded into the neutron mass - remember a neutron star is little more than an unimaginable large atomic nucleus.

The assumption that you seem to be making in your idealized scenario that I did not make is the notion that the hydrogen/helium will necessarily "hit" the surface rather than going into orbit around the core.

Now this idealized scenario is unlikely to happen, what actually happens is that matter forms an accretion disk around the neutron star. The matter in this accretion disk spirals into the star. The inner area of the accretion disk reachs very high temperatures indeed - this is evident from the massive amounts of high energy EM from neutron stars. So I would think that it is very possible that there is some fusing of elements in the accretion disk. But this scenario is nothing like a main sequence types star and this scenario does not lend itself to ever create an actual main sequece type star.

Wouldn't that have something to do with the amount of material falling in toward the core? Suppose "a lot" of material falls in toward the core all at once rather than a small amount? For instance, what happens in a binary star scenario where a main sequence star is "swallowed" by a neutron core? As I understand it, the "crust" of a neutron star is stripped of almost all electrons, meaning it has probably has a charge which might also tend to repel protons. I'm just not convinced that all inflowing material will necessarily hit the core immediately.

What elements are created in the accretion disk (if indeed any are) will be a moot point when they are finally pulled into the neutron star and become 'one with the core'. But again, there is no possible mechanism (that I can envision anyway) that could result in a 'normal' star forming around a neutron star.

The only mechanism that I can conceive of would involve the inflow of massive amounts material toward the core rather than a slow accretion process.
 
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MeteorWayne

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michaelmozina":2ycamtej said:
origin":2ycamtej said:
For instance, what happens in a binary star scenario where a main sequence star is "swallowed" by a neutron core? As I understand it, the "crust" of a neutron star is stripped of almost all electrons, meaning it has probably has a charge which might also tend to repel protons. I'm just not convinced that all inflowing material will necessarily hit the core immediately.

Are you reading what you are writing?

Quiz question...What is the charge of a neutron?

Quiz question 2... What would the charge be on a star made of netrons? (hint... it's the answer to question 1 times the number of neutrons)

Wayne
 
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michaelmozina

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MeteorWayne":2k0vlsfk said:
Are you reading what you are writing?

Yes. :)

Quiz question...What is the charge of a neutron?

http://www.livescience.com/strangenews/ ... harge.html

Well, recent research suggests that the 'net' charge tends to be neutral, but the inner and outer sections tend to be negatively charged with a positive 'middle' that tends to create charge neutrality.

Quiz question 2... What would the charge be on a star made of netrons? (hint... it's the answer to question 1 times the number of neutrons)

Wayne
http://www.astro.umd.edu/~miller/nstar.html

It's not quite a simple as you might think actually. The 'crust' tends to be composed of mostly Nickel and Iron ions that have been stripped of most of their electrons. While the core might be "neutral", that doesn't necessarily speak to the charge of the crust.
 
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origin

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michaelmozina":3vfenx01 said:
Wouldn't that have something to do with the amount of material falling in toward the core?
No

Suppose "a lot" of material falls in toward the core all at once rather than a small amount?
Then "a lot" of material would be absorbed by the neutron star.

For instance, what happens in a binary star scenario where a main sequence star is "swallowed" by a neutron core?
A main sequence star in a binary won't be swallowed by a neutron star (refer to your link in your post to Wayne) to see what a binary system would look like. *EDIT TO ADD* If there was a neutron star that was traveling along not in a binary and it hit the sun it would emerge from the other side enscathed (a little more massive), the point is it would still be a neutron star. Course, the sun would be quite a bit worse for wear!!

As I understand it, the "crust" of a neutron star is stripped of almost all electrons, meaning it has probably has a charge which might also tend to repel protons. I'm just not convinced that all inflowing material will necessarily hit the core immediately.

Refer to your link that I mentioned earlier - the gravitational attraction will overcome any electrostatic repulsion. Why would it have to hit the core immediately? I certainly don't think anybody thinks that.

The only mechanism that I can conceive of would involve the inflow of massive amounts material toward the core rather than a slow accretion process.

I don't see how that would make any difference what so ever. If there was a massive amount of material flowing directly to the core instead of forming an accretion disk it would simply be absorbed by the neutron star more quickly. The heating and high velocities of this material would result in a rather spectacular display of EM radiation but would not result in star formation.

Do you really believe that material will gather around a neutron star and form a plasma that results in a sun like star? Not in this universe, the physics for something like this to happen do not exist on this particular brane...
 
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michaelmozina

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origin":p7ty57qb said:
Refer to your link that I mentioned earlier - the gravitational attraction will overcome any electrostatic repulsion. Why would it have to hit the core immediately? I certainly don't think anybody thinks that.

Well, this seems to be what you're suggesting, whereas I would expect that movement of the material would force at least some of that material to form *around* the core, whereas you seem to insist it's going to be swallowed by the core or "hit" the crust of the neutron star. I think that's where we differ.
 
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UFmbutler

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Michael, I'm not quite sure if I understand what you are saying. Are you saying that hydrogen/helium could go into orbit around the neutron star to such a degree that it would build up a star, with fusion occurring only in the shell around the core? Even if fusion doesn't occur, making it not a star, how could the hydrogen/helium stay in a stable orbit(where by that I mean some other orbit other than an accretion disk) around such a volatile object? How is this supported observationally? If we make the assumption that a star could form around a neutron star core, which sounds ridiculous but let's go with it, what would we expect to see? Well, for one, I would expect to see stars with MUCH stronger magnetic fields than we see. I would also expect high spin rates in the center, assuming the energy from the spinning neutron star is imparted to the surrounding star(a valid assumption, I would think), with frequent bursts of energy as material does strike the neutron star surface. Forgive me if I've misinterpreted you, but even if I have, I'd still like harry to answer such questions as he seems to think it is possible.
 
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Astro_Robert

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As far as neutron stars 'swallowing' other stars. If the total mass was large enough the neutron star would accrete enough mass to exceed the Chandrasekhar limit and evolve to the next stage, presumably a black hole.

As far large volumes of material somehow remaining in orbit around a neutron star such as the rings of Saturn, this seems implausible. Furthermore, if this matter were to initiate fusion, wouldn't the emission of fusion photons alter the orbit of the material, eventually causing it to crash into the core.

I'm not a physicist, but I think the idea of a neutron star surrounded by an orbitting envelope that is undergoing fusion is not in the cards.
 
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michaelmozina

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UFmbutler":39g5b7ei said:
Michael, I'm not quite sure if I understand what you are saying. Are you saying that hydrogen/helium could go into orbit around the neutron star to such a degree that it would build up a star, with fusion occurring only in the shell around the core?

I would be inclined to believe that any fusion that occurs would occur near the neutron crust, not necessarily in the outer shell. Coronal loop activity might generate fusion processes, but I would expect that the bulk of any fusion processes would occur near and around the crust of the neutron core, perhaps as result of materials "hitting" the crust.

Even if fusion doesn't occur, making it not a star, how could the hydrogen/helium stay in a stable orbit(where by that I mean some other orbit other than an accretion disk) around such a volatile object? How is this supported observationally?

The only thing that might make things "stable" would be some type of charge repulsion process between the crust and the material in orbit around the crust. IN terms of observational support, one might make an argument that the sun's magnetic field is due to such a core that spins rapidly compared to the outside material. That might also be useful in trying to explain the sun's 11 year active cycle if the core is rotating slowly in relationship to the spin axis of the outside material.

If we make the assumption that a star could form around a neutron star core, which sounds ridiculous but let's go with it, what would we expect to see? Well, for one, I would expect to see stars with MUCH stronger magnetic fields than we see.

http://arxiv.org/abs/astro-ph/0201434

I would expect that to depend on how large the core might be. Evidently they can "evaporate' over time and eventually become unstable. The strength of the magnetic field would tend to depend on the size of the core, the spin rate of the core, and the material that surrounds the core.

I would also expect high spin rates in the center, assuming the energy from the spinning neutron star is imparted to the surrounding star(a valid assumption, I would think),

I would think so too, and I would suggest that the sun's 22 year rotation cycle, and 5 minute wave cycle could be 'interpreted' as evidence of that kind of process in the core. It could easily be spinning every five minutes and slowly rotating relative to the spin axis.

with frequent bursts of energy as material does strike the neutron star surface.

I would think that would depend on a lot of factors, including the density of material around the core. The "bursts" could take place and yet be pretty much absorbed by the surrounding materials and not reach the "surface" for many thousands of years. The sun does experience 'bursts" of energy by the way in the form of CME's. I personally happen to believe that CME's are partially "externally" driven, but let's not go there in this thread.
 
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origin

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Unfortunately this conversation is spiraling over to mozina land. That is the arena where instead of trying move forward we begin to have the bobing and weaving and purposeful obfuscation that results in circular arguments that ramble on for page after page.

You can see it in the excessive use of qualifiers for most if not all of Michael statements, such as:

"I would be inclined to believe..."
"Coronal loop activity might... "
"That might also..."
"I would expect that to depend..."
"I would suggest that the sun's 22 year rotation cycle, and 5 minute wave cycle could be 'interpreted'..."
"I would think that would depend on a lot of factors..."
And my favorite
"I personally happen to believe that..."

No evidence just repeated unsubstantiated conjecture ad infinitum...

So with that I'm done; been there, done that, just a waste of time.
 
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