Plasma Cosmology - Woo or not

[sol invictus]

Well,

With the EM forces on stars being negligible, what do we mean. Isn't my reference saying what you are saying? That the EM interaction could only account for 10% of the seen discrepancy?

No!

Your reference was talking about gas. Rotation curves are observed for stars as well, and for stars EM forces could account for at most .000000000000000000000001% of the discrepancy.

 

[Wangler]

It could be from dark matter's gravitational pull, or it could be electromagnetic - except that we've seen that it cannot be EM, because EM forces on stars are negligible.

What about the solar magnetic field, averaging about 6 nT, and extending out the heliopause at about ~100 AU?

 

[Zeuzzz]

The acceleration is determined only by distance from the center of mass being orbited and the magnitude of that mass - it has nothing at all to do with the direction the star is moving.

Thats if you assume fisrt that there is a single centre of mass. In Peratts there are four centre of masses (in the plasma filaments) for the milky way, and I think these different mass distributions were the main reasons why his simulations showed a flat rotation curve.

 

[Tubbythin]

What about the solar magnetic field, averaging about 6 nT, and extending out the heliopause at about ~100 AU?

How would this explain star's rotational speed around the galactic centre?

 

[Tubbythin]

Thats if you assume fisrt that there is a single centre of mass. In Peratts there are four centre of masses (in the plasma filaments) for the milky way, and I think these different mass distributions were the main reasons why his simulations showed a flat rotation curve.

Zeuzzz, pick a spiral galaxy. Any one (that's isolated). Now, tell us where the centre of mass is.

 

[Reality Check]

I don't think I'm talking off topic, I just don't think that I am explaining my thoughts very well.

Let's picture a very large cloud of gas, say two or three times the diameter of the Milky Way. This cloud of gas is ionized, and has some associated electromagnetic field.

Further, assume that this cloud of gas has begun the first step in a graviational collapse.

Now, I certainly cannot solve the governing equations, but lets assume that the EM field strength is such that it can counteract gravitational collapse, either by just counteracting gravity, or by "spinning up" the gas cloud. Let's assume for the sake of my argument, that the "spinning up" is what causes the collapse to halt.

So, here we have some sort of EM-gravity equilibrium, on a global scale. The cloud is rotating faster than expected, because of the EM "spin up".

However the EM forces might make the cloud spin slower then expected. It depends on the direction of the spin with respect to the magnetic field.

Now, over time, local instabilities result in star formation at various places in the global cloud.

When a star begins to shine, we see it, and note that it's rotational period is shorter than expected.

the only problem that I see with a contrived scenario like this one, is that the star would just move to a larger radius orbit if it was not charged, one that would match our Keplerian explaination perfectly.

But, perhaps it would take many, many rotations for this relaxation to take place.

This whole idea might not be plausible, but does my explaination make sense?

This is pretty much Peratt's debunked model of galaxy formation with clouds rather than filaments.
You are right that one problem is that as soon as stars form they are no longer under any significant EM - even if they were charged as in your last paragraph. The force on them by the galactic magnetic field is many orders of less than that of gravity (26 orders of magnitude by memory).

The other problem is that even ionized gas has mass so your "spinning up" (or down) would be insignificant.
Thus the whole idea is not implausible but has no effect on galaxy formation.

Galaxy formation models are not quite off topic since it brings up a cosmological point: How come we have not seen galaxies being formed?

 

[sol invictus]

What about the solar magnetic field, averaging about 6 nT, and extending out the heliopause at about ~100 AU?

What about it?

First, we were talking about stars orbiting the galactic center, so I'm not sure why that's relevant.

Second, the force that field would exert on an object with the mass and charge of a star is something like 10^-26 (give or take 5 orders of magnitude or so) times the force of gravity of the galaxy.

 

[Reality Check]

Thats if you assume fisrt that there is a single centre of mass. In Peratts there are four centre of masses (in the plasma filaments) for the milky way, and I think these different mass distributions were the main reasons why his simulations showed a flat rotation curve.

That is wrong. You seem to have forgotten (or never known) that Peratt's model totally ignores gravity. So the presence of "four centre of masses" does not matter.

ETA: Astronomers would have also noticed the "four centre of masses" in the Milky Way. For some reason they seem to be really interested in the distribution of stars in our galaxy!

 

[sol invictus]

Thats if you assume fisrt that there is a single centre of mass.

It's becoming more and more apparent that you've not even had a high-school level physics course.

If I may ask, what's your level of education in physics, Zeuzzz?

 

[DeiRenDopa]

Wangler: When a star begins to shine, we see it, and note that it's rotational period is shorter than expected.

the only problem that I see with a contrived scenario like this one, is that the star would just move to a larger radius orbit if it was not charged, one that would match our Keplerian explaination perfectly.

But, perhaps it would take many, many rotations for this relaxation to take place.

This whole idea might not be plausible, but does my explaination make sense?

Sans any characterisation of 'stars', 'galaxies', etc - i.e. entirely qualitatively - it might.

However real stars in real galaxies have well-constrained estimates of age, orbital period, and so on.

A characteristic rotation period might be 100 million years; a characteristic age might be 5 billion years ... more than enough time for any 'cut-off-at-birth' forces to have disappeared from their orbits.

Now older stars tend to be distributed with a larger 'scale height' (a measure of their distribution above and below the galactic plane) than younger stars (and gas), but that distribution is pretty much what you'd expect given the estimated distribution of mass in the disk and the stars' ages ... and in terms of the estimated mass interior to the stars (as a function of radius), there is no discrepancy (within the estimated uncertainties).

Or, to put it another way, there is no 'age effect' observed; such an effect would be expected under your idea.

 

[Wangler]

How would this explain star's rotational speed around the galactic centre?

I dunno, everyone says that stars are electrically neutral (true, as far as I know), and that therefore they cannot be accelerated by galactic EM fields in a way that would explain galaxy rotation curves.

So, I say what about interactions with the vast magnetic field/solar wind/plasma that most stars undoubtedly have?

 

[Wangler]

Wangler: When a star begins to shine, we see it, and note that it's rotational period is shorter than expected.

the only problem that I see with a contrived scenario like this one, is that the star would just move to a larger radius orbit if it was not charged, one that would match our Keplerian explaination perfectly.

But, perhaps it would take many, many rotations for this relaxation to take place.

This whole idea might not be plausible, but does my explaination make sense?

Sans any characterisation of 'stars', 'galaxies', etc - i.e. entirely qualitatively - it might.

However real stars in real galaxies have well-constrained estimates of age, orbital period, and so on.

A characteristic rotation period might be 100 million years; a characteristic age might be 5 billion years ... more than enough time for any 'cut-off-at-birth' forces to have disappeared from their orbits.

Now older stars tend to be distributed with a larger 'scale height' (a measure of their distribution above and below the galactic plane) than younger stars (and gas), but that distribution is pretty much what you'd expect given the estimated distribution of mass in the disk and the stars' ages ... and in terms of the estimated mass interior to the stars (as a function of radius), there is no discrepancy (within the estimated uncertainties).

Or, to put it another way, there is no 'age effect' observed; such an effect would be expected under your idea.

Hey, guys, I have been loose and incorrect with my nomenclature, which may be confusing in a conversation like this.

Everytime I have mentioned rotation, I am really speaking about the revolution of stars about the galaxy whole.

Stars rotate about their axis, they revolve around the galactic center.

 

[Reality Check]

I dunno, everyone says that stars are electrically neutral (true, as far as I know), and that therefore they cannot be accelerated by galactic EM fields in a way that would explain galaxy rotation curves.

So, I say what about interactions with the vast magnetic field/solar wind/plasma that most stars undoubtedly have?

So we reply once more: None.
The "vast" (actually tiny in extent and strength astronmically) magnetic field/solar wind/plasma that most stars undoubtedly have is still less than 10 times the galactic magnetic field and still about 10^-25 of the force of gravity. Solar magnetic fields are also local.

 

[Wangler]

So we reply once more: None.
The "vast" (actually tiny in extent and strength astronmically) magnetic field/solar wind/plasma that most stars undoubtedly have is still less than 10 times the galactic magnetic field and still about 10^-25 of the force of gravity. Solar magnetic fields are also local.

Typical values for the galactic magentic field are 2-10 microgauss. I quoted 6 microgauss above.

Let's stick with 2 microgauss as estimated for the large scale galactic field (Rand & Kulkani 1989; Han & Qiao 1994).

For the stellar magnetic field, we use the average solar strength as provided here: http://www.oulu.fi/~spaceweb/textbook/solarwind.html, which is 6 nanoTesla.

One Tesla is 10^4 Gauss, so one nanotesla is 10^-5 Gauss, or 10 microGauss.

So, a typical star, like our sun, has a magnetic field strength that is 30 times the global galatic field strength, on average. (6 nT = 60 uG, which is 30 times 2 uG).

With the 6 uG number, stellar fields are still 10 times the strength of the galatic field.

 

[DeiRenDopa]

Wangler, what does the stuff in your posts have to do with whether PC is woo or not?

 

[sol invictus]

With the 6 uG number, stellar fields are still 10 times the strength of the galatic field.

But... so what? I thought the issue was whether EM effects could explain galactic rotation curves. What does the relative magnitude of solar and galactic magnetic fields have to do with that?

 

[Reality Check]

Once more into the breech:

1. Stellar magnetic fields are local and do not affect the motion of the star in the galaxy. It is the motion of stars through the galactic magnetic field that pc woo-mongers are deluded into thinking can have an effect on stars.
2. "10 times the strength of the galactic field" is still 25 magnitudes less than that required to make the magnetic force equal that of gravity. That is 0.0000000000000000000000001% of the required strength assuming that the star has the maximum theoretical charge that it can hold.

Is there anything there that you cannot understand Wangler?

 

[Dancing David]

I cant. Peratts model does produce a flat rotation curve with the simulated two galactic wide plasma filaments, but falls short of offering a tenable solution on the stellar scale.

Maybe gravity obeys the Biot Savart force law when matter is flowing in a filament formation, as well as elecriticy

So Plasma Cosmology can not provide an alternative to DM when explaining flat rotation curves.

Thank you for that admission.

 

[Dancing David]

I don't think I'm talking off topic, I just don't think that I am explaining my thoughts very well.

Let's picture a very large cloud of gas, say two or three times the diameter of the Milky Way. This cloud of gas is ionized, and has some associated electromagnetic field.

Further, assume that this cloud of gas has begun the first step in a graviational collapse.

Now, I certainly cannot solve the governing equations, but lets assume that the EM field strength is such that it can counteract gravitational collapse, either by just counteracting gravity, or by "spinning up" the gas cloud. Let's assume for the sake of my argument, that the "spinning up" is what causes the collapse to halt.

So, here we have some sort of EM-gravity equilibrium, on a global scale. The cloud is rotating faster than expected, because of the EM "spin up".

Now, over time, local instabilities result in star formation at various places in the global cloud.

When a star begins to shine, we see it, and note that it's rotational period is shorter than expected.

the only problem that I see with a contrived scenario like this one, is that the star would just move to a larger radius orbit if it was not charged, one that would match our Keplerian explaination perfectly.

But, perhaps it would take many, many rotations for this relaxation to take place.

This whole idea might not be plausible, but does my explaination make sense?

If it applied to all the stars in a galaxy beyond the kepler motion radius, sure. But it sounds like it would apply to highly (very highly) charged plasma clouds rather than accreting stars.

 

[Dancing David]

Thats if you assume fisrt that there is a single centre of mass. In Peratts there are four centre of masses (in the plasma filaments) for the milky way, and I think these different mass distributions were the main reasons why his simulations showed a flat rotation curve.

Wow can I get some sausage patties with that Waffle!

Sorry Zeuzzz, you have gone from unprovable to unprovable.