Something new under the sun

[ben m]

If true, why does the sun have a non-circular heliopause and a comet tail like heliosheath? Why does it have a bow shock? It has to be traveling a differentt velocity than the ISM and should be typical of most stars. You don't want the sun to be special, do you?

Because the Sun is moving at 26 km/s relative to the local ISM. (Compare that to 220 km/s net orbital velocity.) What direction do you think the ISM is moving in? Do you think the Sun is blasting through it towards Vela (which would be the case if the Sun were orbiting gravitationally while the ISM were pinned to a Peratt-style fast disk?) or towards Cygnus (which would be the case if the ISM were pinned down, and the Sun moving faster)? Any guesses? No? Sorry, buddy, the local ISM is blowing in from Auriga---from the galactic anticenter and a bit north, i.e. as inconsistent as possible with your off-the-cuff "I bet I found a discrepancy OMG". Of course, you just thought this objection up 10 seconds ago, so I have no doubt that you can forget about it at least as quickly.

This simply means that the Sun and the Local Cloud aren't on perfectly circular orbits, but rather on slightly elliptical ones. That's how orbital mechanics works.

And why do stars in our vicinity move relative to one another if we're all along for the great galactic dark matter ride? You don't want are little region of the galaxy to be atypical, do you?

That's not how orbital mechanics works. Dark matter+baryons set up a central-force-law attractive potential. Every star/DEG/cloud follows an independent orbit in that potential. There are many possible orbits; we're on one of them. If you've been thinking of it as a fixed fluid that "sweeps things along", you've been wrong.

http://www.physicsmyths.org.uk/darkmatter.htm

Ah, yes, the repository of all accurate physics analysis, physicsmyths.org.uk. You realized you just quoted a site which simply repeats the exact same arguments you've been making throughout this thread? If PC is wrong, it's wrong no matter who says it.

 

[Tubbythin]

Actually, Tubbythin, 21cm emitting regions can be partially ionized; I don't know what the extrema are, but 50%-ionized, 50% neutral clouds are reasonably common. I'm willing to call that a plasma.

Point taken, I think I was a bit lazy with my posts...
Sure. There will always be an equilibrium ratio between ions and atoms in regions where ionization takes place. But this does not mean HI clouds are not neutral, it means HII clouds are not fully ionized. Hence, HI clouds are not plasmas.

 

[ben m]

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No one is ruling out the effects of gravity, but electromagnetic forces are significant too, and dominate while charged particles smaller than grains are present.

Neutrino forces are significant too, and dominate when particles carrying weak charge are present. Strong interactions are significant too, and dominate when colored objects are present. Casimir forces are significant too, and dominate when polarizeable materials are present. And so on. It's easy to say, but hard to make interesting.

What's your point? What are you claiming that EM fields actually do? That they contribute some magnetic pressure to the equation-of-state of stellar interiors? Fine. That they dominate the dynamics in the inner regions of HMXBs? Probably true. Shrink the equilibration length scales in otherwise-collisionless plasmas? Doubtless. But all of these things are well-known and no one argues against them.

Please list the actual astrophysical phenomena where you think that EM fields are important and have been neglected. Is it the same list that we've been debunking for 21 pages now? Do EM fields power the Sun, make the Sun orbit the galaxy, accelerate galaxies towards one another, make partially ionized hydrogen clouds orbit the galaxy, confine hot plasma in the centers of galaxy clusters, and prevent the formation supermassive black holes? No they don't.

 

[iantresman]

Actually, Tubbythin, 21cm emitting regions can be partially ionized; I don't know what the extrema are, but 50%-ionized, 50% neutral clouds are reasonably common. I'm willing to call that a plasma.

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The extremes of degree of ionization that can make an ionized gas behave as a plasma may be calculated, and depends on several factors. You are quite right that some partially ionized may require a degree if ionization of 50% for them to behave as, and be called a plasma.

But recall that Irving Langmuir's research into ionizated gases in discharge tubes whose degree of ionization is tiny. For example, in so-called cold plasmas, the degree of ionization is below 10^-4 (0.01%) (Ref). The degree of ionization of H I neutral hydrogen regions is about 10^-4.

In other words, what is commonly described as a "HI neutral hydrogen region", has a small but significant degree of ionization (about 10^-4), that together with other properties, defines it has a partially ionized cold plasma.

ie. a "neutral" hydrogen HI region is a plasma.

 

[Reality Check]

.
The extremes of degree of ionization that can make an ionized gas behave as a plasma may be calculated, and depends on several factors. You are quite right that some partially ionized may require a degree if ionization of 50% for them to behave as, and be called a plasma.

But recall that Irving Langmuir's research into ionizated gases in discharge tubes whose degree of ionization is tiny. For example, in so-called cold plasmas, the degree of ionization is below 10^-4 (0.01%) (Ref). The degree of ionization of H I neutral hydrogen regions is about 10^-4.

In other words, what is commonly described as a "HI neutral hydrogen region", has a small but significant degree of ionization (about 10^-4), that together with other properties, defines it has a partially ionized cold plasma.

ie. a "neutral" hydrogen HI region is a plasma.

iantresman, "small but significant degree of ionization"?
I know little about plasma physics but can use Wikipedia to look up basic facts. You may want to read the article yourself and read the Degree of ionization section which states: "Even a partially ionized gas in which as little as 1% of the particles are ionized can have the characteristics of a plasma". This is not a lower limit on the degree of ionization needed for a plasma to exist but you are claiming that a 0.01% degree of ionization is enough.

 

[Zeuzzz]

you are claiming that a 0.01% degree of ionization is enough.

Ian is not claiming such a thing. He had quoted an expert (infact nobel laureate) in that field that says this.

Are you disagreeing with him?

From looking up it quickly on wikipedia?

Your joking, right?

 

[Zeuzzz]

Plasma Cosmology Apologists,
Since you claim Peratt as your PC guru and that his model includes gravity then explain his own conclusions from a 2005 conference:

Much more research is needed in the following areas.
(1) The difference in rotational speed of stars vs plasma filaments in Spiral Galaxies.
(2) "Dirty Plasma" effects.
(3) Plasma Density as functions of time and position within a Spiral Galaxy. (4) Simplified approximate "Gravitational + EM Plasma" equations which transparently describe the interplay of gravitational and EM Plasma forces which determine the essential features of Spiral Galaxies.
5) The role of Conservation of Angular Momentum in the evolution from plasma to Elliptical to Irregular to Spiral Galaxies.

P.S. Gravitation lensing by dark matter -NASA Finds Direct Proof of Dark Matter (sooner or later one of you is going to have to refute this!)​

Your point?

This shows that Peratt is being honest, he is not claiming his model is definitive, and openly talks about what needs to be improved to make it fully applicable. He is quite open about his model. If you want, I can give you his e-mail address at Los Alamos Laboratory and you can inform him on what you think is wrong with his work in person?

since you seem to have made a whole host of erroneous points recently, I will ask you again what your main problem is with his galaxy model. And try to be specific.

 

[ben m]

The point, which I think Iantresman and Zeuzz have caught onto:

Yes, the 21-cm lines probably come from clouds of partially ionized gas which, for Peratt's purposes, would count as "plasma".

Therefore (and I'm not sure they've caught onto this) 21cm HI regions should respond to whatever "plasma cosmology". Therefore, the fact that 21cm HI rotation curves (responding to gravity plus Perrat's hypothesized fields) agree with stellar rotation curves (responding to gravity alone, decoupled from Perrat's fields) tells you that Perrat's fields, if they're there at all, can't do very much.

 

[Zeuzzz]

And so..okay... I did read the stuff about pulsars and double radio galaxies.

What would you like to read on the subject? They are posibilities, but what dataum do they explain that is not explained by the current models or what data do they explain better.

And so what provides the force that claim we observe when it comes to something you are avoiding explaining. And you have continued to avoid.

Are you really saying the same thing that people complain about with dark matter? The force exists because you say it is accelerating the stars in their orbits by, that amount above the level explained by gravity minus dark matter.

Because I swear that is just what I read. That maybe you could compute the field needed by taking the motion of the star and its' mass since you can see it the same way , right/

And so the aggregate figure for the EM field that moves the stars would be comparable to the motion that is allegedly explained by dark matter, in other words the EM field would have the same effect as 20 times as much mass as there is baryonic matter? Can you agree to that? Because then if you give me a figure for the charge on a star we can do the computation as an aggregate?

Do you agree?

And so while dark matter might be inferred from the rotation of stars, you are now saying that this EM force can be observed exactly the same way.

Here is the problem Zuezz and what you are obviously trying to avoid at any cost.

What size magnetic field are we talking about?

C'mon, unlike dark matter which can be inferred through normal gravitation plus dark atter, you are making a different claim here are you not.

Are you now saying what I have been asking along for the size and scale of?
There is an EM force that is accelerating the stars faster in thier orbits than can be accounted for by the visible baryonic matter?

I will ask again, what scale from Perrat's model put a figure to it, what was the Gauss in the 10cm experiement?

What size field did Perrat use in his plasma simulations of alleged galaxy formation?

Was it 4.3 Gauss? And ten cm?

So what scale would this magnetic or EM field be, what size 1:1000000
gives an absurdly high figure.

So what is yours? What is your scale , what did perrat use and how do you scale it to a glaxy. C'mon.
Otherwise I will take the speed that he stars is supposed to have without extra mass and subtract it from speed that it shows. And then I will factors in the mass of the star.

So say we have star at 1000000 kilos, and it goes 1kph faster than it should. Are you saying then that the EM force would be the same as the mass of the star times the speed of the star over that expected for the star's spped by gravity without the dark matter?

Would that be fair?

I can get the actual figures if you want the mass of the star and the variant motion if you would like. But you would need to tell me what charge I can assign the star in the equation. because that is going to them say what size the magnetic field has to be.

because here is the deal at the end thier will be a figure, the size of the magnetic field required to change the speed of the star.

So is that what we can do?

Do you agree to that?

And what will you say if the EM field turns out to be foolishly high and one that has never been measured?

David. That post has nearly twenty questions in it. Could you just choose your main one or two points you want me to answer and i'll do my best.

Thankyou.

 

[Reality Check]

Your point?

This shows that Peratt is being honest, he is not claiming his model is definitive, and openly talks about what needs to be improved to make it fully applicable. He is quite open about his model. If you want, I can give you his e-mail address at Los Alamos Laboratory and you can inform him on what you think is wrong with his work in person?

since you seem to have made a whole host of erroneous points recently, I will ask you again what your main problem is with his galaxy model. And try to be specific.

Read my posts - no gravity in the model + no justification of neglecting gravity = invalid model.

 

[Reality Check]

Ian is not claiming such a thing. He had quoted an expert (infact nobel laureate) in that field that says this.

Are you disagreeing with him?

From looking up it quickly on wikipedia?

Your joking, right?

I also looked at his reference which is the "Handbook of Sputter Deposition Technology" in the Plasma in a Glow Discharge section. No mention of plasmas in space.

 

[iantresman]

iantresman, "small but significant degree of ionization"?
I know little about plasma physics but can use Wikipedia to look up basic facts. You may want to read the article yourself and read the Degree of ionization section which states: "Even a partially ionized gas in which as little as 1% of the particles are ionized can have the characteristics of a plasma". This is not a lower limit on the degree of ionization needed for a plasma to exist but you are claiming that a 0.01% degree of ionization is enough.

.
It can be enough, but not always. It depends on the plasma. Alfvén writes:

".. as far as collision processes are concerned, plasmas with degrees of ionization larger than 1 per cent are to be considered as highly ionized. -- . Cosmical Electrodynamics (Ch.4 Plasma, p.145) (1963)"​

and

.. provided the electron temperature is not too high, plasmas with a degree of ionization larger than 1 per cent can often be considered as completely ionized as far as collision processes are concerned.-- . Cosmical Electrodynamics (Ch.4 Plasma, p.180) (1963)​

But also:

"In cold plasma, the degree of ionization is below 10^-4 -- Kiyotaka Wasa, Shigeru Hayakawa, Handbook of Sputter Deposition Technology: Principles, Technology and Applications (page 95) (1992), William Andrew Inc., 304 pages,"​

In other words, although the degree of ionization may be around just 10^-4, a partialy ionized gas, if it satisfies other characteristics, may be better described as a plasma, albeit a weakly ionized plasma.

 

[BeAChooser]

Quote:
That statement is taken out of context. Here's the sentence before that one: "The mean stellar radial velocities of the dSphs are compared to recent velocity measurements of neutral hydrogen clouds seen in the direction of some of these dwarfs." They weren't talking about rotational velocities and I see no reason why radial velocities wouldn't agree.

Radial means line-of-sight; almost all galactic dynamics comes from radial velocity measurements. The opposite of "radial velocity" is "transverse velocity", which you could measure only via proper motions. It does not mean "velocity towards the galactic center" which is the opposite of "rotational velocity".

But the line of sight velocities in this case are towards distant dSph galaxies and hence very likely towards the center of those objects since the stars in those objects closest to us would likely be the ones most easily seen and measured. Again, I wouldn't expect to see large differences in the velocity of plasma (or gas) and stars moving towards the center of those galaxies. Would you?

Quote:
You also cut off the rest of the sentence after the words "in good agreement". It qualifies that saying "in the case of And III, indicating a physical association, but not in the case of And V (probably a chance superposition)."

It's in good agreement with the general model of a dark-matter-rich galaxy. In the case of subgroup AndIII, there is furthermore good agreement between the velocity of stars in this subgroup and gas also in the subgroup. The stars in And V do not have the same velocity as the gas which appears to be "in And V" because that gas is in fact a large distance behind the stellar group. Read the paper, BAC, don't just quote-mine.

Except the article you linked doesn't actually say what you just claimed. It only states "If this low significance HI detection at And III is confirmed, it likely represents gas that is physically associated with the dSph. By contrast, the 21 cm velocity of the HVC 368 cloud in the direction of And V is ...snip ... clearly inconsistent with the optical value. As originally suspected⁵, this cloud is likely to be a fragment of a larger neighboring gas cloud (complex ‘H’) that happens to be superposed on And V."

Reference 5 above is "5. L. Blitz, and T. Robishaw, “Gas rich dwarf spheroidals,” Astrophys. J. in press (astro-ph/0001142), 2000" and it only says And V "is an intriguing case not only because of the apparent association of the HI with the galaxy, but also because the HI is listed as HVC 368 in the compilation of Wakker & van Woerden (1991). ... snip ... As shown in Figure 2, however, HVC 368 lies quite close to HVC 287, also known as complex H. ... snip ... The proximity of the two clouds and the similarity of their radial velocities suggests that the smaller cloud may be a fragment of the larger one, and may thus be an unrelated foreground object. In that case, the probability of a chance coincidence is much higher than the value of ~ 10 ^-2 for the other dSph galaxies."

There is nothing definite in either source. It is as I said ... the mainstream choses to believe one measurement because it fits their preconceptions and not believe another because it doesn't. And at the same time they choose to believe hundreds of unusual associations, such as http://www.haltonarp.com/articles/research_with_Fred/illustrations/figure_1_b.jpg and http://arxiv.org/pdf/astro-ph/0206411 ) are nothing more than coincidence. Even though the calculated probabilities of them being chance coincidence are many orders of magnitude smaller than the case they just ruled out. How telling.

Quote:
And do you really understand what they were measuring in the above case? ... snip ... Yes, measuring how fast the entire dwarf is moving around M31.

Wrong. They are measuring how fast the star supposedly moves with respect to the dwarf galaxy. And I know this because they talk about using that data to calculate the dark matter associated with the dwarf galaxy, not M31.

 

[sol invictus]

.
No one is ruling out the effects of gravity, but electromagnetic forces are significant too, and dominate while charged particles smaller than grains are present. See:

You can say this as many times as you want, but it's still false. We already talked about this, and you now seem to be pretending that conversation never happened.

Belz made a nice point earlier that you can appreciate even without knowing any physics: ALL matter is made from particles which are of zero size (to the best of our knowledge), and yet gravity dominates sometimes.

Oops!

 

[BeAChooser]

I'm also amused that BAC is questioning the general accuracy of the galaxy rotation curve measurements ... the same radial (line-of-sight doppler) measurements that are said to agree with Peratt's simulations.

I don't know if Peratt investigated or published simulation results as far as 60 kpc out from the galactic center where these new measurements are coming from. Hence I don't know what his model would have predicted in that case. Perhaps it would have predicted a falling off of the rotation curve as apparently the data actually shows. I specifically questioned the measurements in this case because a mainstream source said measurements in this case were difficult and the material measured rare.

 

[sol invictus]

Therefore (and I'm not sure they've caught onto this) 21cm HI regions should respond to whatever "plasma cosmology". Therefore, the fact that 21cm HI rotation curves (responding to gravity plus Perrat's hypothesized fields) agree with stellar rotation curves (responding to gravity alone, decoupled from Perrat's fields) tells you that Perrat's fields, if they're there at all, can't do very much.

So now the cranks are claiming that gas in galaxies rotates at totally different velocities than stars. Try to nail them down on that statement... of course even if you do they'll simply change the subject and pretend it never happened.

I'm still not over my amusement at the first paragraph of this:

http://www.plasma-universe.com/index.php/Galaxy_formation

These idiots can't even get the basic terminology straight - they don't know what "flat rotation curve" means. Even better, because of that stupid misunderstanding they've invented a "prediction" which totally contradicts the data!

 

[sol invictus]

What do you know... if it isn't our very own Ian Tresman that's responsible for that website!

http://www.plasma-universe.com/index.php/Wikipedia:Contact

I'm beginning to think there are only about two or three of these crackpots in the world. What I still really don't understand is what drives them forward on this. Like I said, there are far more interesting crackpot ideas out there - ones that might even be correct. This stuff is just childish.

 

[iantresman]

.. and yet gravity dominates sometimes.

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Agreed. An sometimes electromagnetism dominates, as it does in jets, the interplanetary medium, the interstellar medium, and the intergalactic medium.

 

[sol invictus]

.
Agreed.

I see. So now you've flipflopped again and agree that this statement is false?

No one is ruling out the effects of gravity, but electromagnetic forces are significant too, and dominate while charged particles smaller than grains are present.

 

[iantresman]

I also looked at his reference which is the "Handbook of Sputter Deposition Technology" in the Plasma in a Glow Discharge section. No mention of plasmas in space.

.
A plasma is a plasma no matter where it is. If you can have plasmas with a degree of ionization as low as 10^-4 in the laboratory, so too in space.

But just to be sure, Britannica tells us:

The greater proportion by far of interstellar medium, however, exists in the form of neutral hydrogen clouds referred to as H I regions. Because the heavy atoms in such clouds are ionized by ultraviolet radiation (or photoionized), they also are considered to be plasmas, although the degree of ionization is probably only one part in 10,000" (my emphasis) -- "natural plasmas​