JREF forum bashing of Anthony Peratt's work...

[Nereid]

If you could measure the distribution of mass in the Sun, divided according to charge (including dipoles of neutral particles/atoms), and you drew a line tangential to the Sun's movement around the galactic core, then I would expect to see a very subtle imbalance in the distribution either side of that line. Suitably charged particles should be slightly leading the motion. Unfortunately it's not a measurement that can be easily taken, so it's likely to remain speculation.

If it's not testable, even in principle, then that's the end of it, right?

Probably the only way to decide whether it's probable is to measure the various fields and decide on the best explanation for them, which may or may not then imply that the Sun's orbit is dominated by electricity instead of dark matter.

Well, as far as I know, the motion of the Sun (actually the solar system barycentre) around the centre of the Milky Way galaxy does not require any CDM ... the estimated mass of stars, gas, plasma, and dust 'interior' to the Sun's position is great enough to account for all relevant observations (of the Sun's motion), assuming Newtonian gravity (at the level appropriate for the observations, that's the same as GR). Do you know of any material which is contrary to this?

Back to Peratt's papers - what observations of stars do you think could be used (if only in principle) to test Peratt's model?

No, we don't throw anything out. We keep it all, for the same reason the courthouse keeps all of the proceedings of court cases.

Fair enough.

What use, though, is Peratt's model, if quasars (however defined) are 'actually' at very different distances from us than those implied by their redshifts and the Hubble relationship? Ditto galaxies. For example, unless there is at least one independent way to estimate the distance to quasars and galaxies - independent of the Hubble relationship and Peratt's model - how could you test that model?

For example there is Pierre-Marie Robitaille's article, here which you so quickly announced as a fail, and which you have so far failed to demonstrate why; because if it is not a fail, makes basically all your posts non-conversations, as you say, doesn't it?

Oh it'd do a lot more than that!

If it's not a fail, great swathes of physics would need to be re-written ... as well as all the branches of engineering that have been built on those parts of physics, including, no doubt, much of plasma physics.

However, let's stick - in this thread at least - to Peratt's model, shall we?

I don't care if they overlap in terms of spectrum a little here and there - it it's outside the visible spectrum but excites colloidal silver some (old photographic plates can do this) it just shifts more info into the visual print - I'm not into measuring IR values off astronomical images just yet!

Glad to hear that you're having fun with FITS!

One thing to be careful with photographic emulsion is the non-linear response at the faint end, especially if you don't have anything on such images which you can use to calibrate it.

Thinking about NGC 4346 and diocotron instabilities: do you think it'd be worthwhile (or even just fun?) to try to outline a research programme on the topic? It might make a good addition to this thread.

[Goldminer]

Goldminer wrote:No, we don't throw anything out. We keep it all, for the same reason the courthouse keeps all of the proceedings of court cases.

Fair enough.

What use, though, is Peratt's model, if quasars (however defined) are 'actually' at very different distances from us than those implied by their redshifts and the Hubble relationship? Ditto galaxies. For example, unless there is at least one independent way to estimate the distance to quasars and galaxies - independent of the Hubble relationship and Peratt's model - how could you test that model?

Yes, Nereid, and I am asking since equity must do equity; how has the Hubble red shift and Peratt's model been independently verified. You have developed another straw argument here. The Hubble relationship is just another speculation, inbred by consensus. It is not independently verified, is it? One man's thesis does not require another's rules to stand on its own, just as Pierre-Marie Robitaille's article stands on its own.

I think the main essence of Peratt's model would survive in a stable non-expanding universe. Incidentally, Arp's model does not preclude an expanding universe if one allows, for instance; that a QUASAR developing into a new conventional galaxy, develops in its own expanding space, necessitating the surrounding space to move over. I'm just saying, that in the vein of proposing Dark Matter-Energy, Big Bangs, Inflation, Black Holes and such, the foregoing conjecture has just as much chance of success. I shall not inveigh this conjecture upon you just as you should not insist that the Hubble conjecture is the ultimate standard.

[seb]

If you could measure the distribution of mass in the Sun, divided according to charge (including dipoles of neutral particles/atoms), and you drew a line tangential to the Sun's movement around the galactic core, then I would expect to see a very subtle imbalance in the distribution either side of that line. Suitably charged particles should be slightly leading the motion. Unfortunately it's not a measurement that can be easily taken, so it's likely to remain speculation.

If it's not testable, even in principle, then that's the end of it, right?

In the same way that the untestable interior of a black hole is the end of black hole theory, yes. I don't know how it could be measured, but perhaps a way could be found in the future.

Probably the only way to decide whether it's probable is to measure the various fields and decide on the best explanation for them, which may or may not then imply that the Sun's orbit is dominated by electricity instead of dark matter.

Well, as far as I know, the motion of the Sun (actually the solar system barycentre) around the centre of the Milky Way galaxy does not require any CDM ... the estimated mass of stars, gas, plasma, and dust 'interior' to the Sun's position is great enough to account for all relevant observations (of the Sun's motion), assuming Newtonian gravity (at the level appropriate for the observations, that's the same as GR). Do you know of any material which is contrary to this?

The "flat" (-ish) velocity curve for the galaxy shows that the stars do not orbit the centre of the Milky Way in the way expected due to the observable mass. Adding unobservable mass to make the orbits fit doesn't count. As it happens, the Sun lies in a cross-over point between that obtained both with and without dark matter, but that leads to at least four electrical possibilities: (i) our ability to distinguish between electrical and gravitational influences in our solar system is limited; or (ii) the Sun's orbit is electrically dominated and the actual gravitational mass of the solar system is lower than inferred from its apparent quantity; or (iii) our solar system, perhaps due to its fortuitous location, is less influenced by electricity than the rest of the galaxy; or (iv) gravity really is an electric effect in which case our Sun lying on the cross-over point is not simply coincidence, but expected.

[Nereid]

The "flat" (-ish) velocity curve for the galaxy shows that the stars do not orbit the centre of the Milky Way in the way expected due to the observable mass. [...] As it happens, the Sun lies in a cross-over point between that obtained both with and without dark matter

Do you have a source for this?

that leads to at least four electrical possibilities: (i) our ability to distinguish between electrical and gravitational influences in our solar system is limited;

But the limits are well-established, aren't they? For example, as far as I know, the observed positions of all solar system bodies are consistent with 'gravitational' ephemerides (to within the relevant uncertainties), except for some comets.

or (ii) the Sun's orbit is electrically dominated and the actual gravitational mass of the solar system is lower than inferred from its apparent quantity;

I don't understand this; can you explain please?

or (iii) our solar system, perhaps due to its fortuitous location, is less influenced by electricity than the rest of the galaxy; or (iv) gravity really is an electric effect in which case our Sun lying on the cross-over point is not simply coincidence, but expected.

None of these speculations were tested in Peratt's model/simulation, were they? And, as far as I know, no other models - much less simulations - of anything like this exist (at least in published form), do they?

[seb]

The "flat" (-ish) velocity curve for the galaxy shows that the stars do not orbit the centre of the Milky Way in the way expected due to the observable mass. [...] As it happens, the Sun lies in a cross-over point between that obtained both with and without dark matter

Do you have a source for this?

Our trusty friend, Wikipedia: http://en.wikipedia.org/wiki/Dark_matter_halo

that leads to at least four electrical possibilities: (i) our ability to distinguish between electrical and gravitational influences in our solar system is limited;

But the limits are well-established, aren't they? For example, as far as I know, the observed positions of all solar system bodies are consistent with 'gravitational' ephemerides (to within the relevant uncertainties), except for some comets.

Undoubtedly, but they do not conform to the theories of gravity, they conform to the equations of gravity. The physical process that gives rise to those equations still remains contentious even in the mainstream.

or (ii) the Sun's orbit is electrically dominated and the actual gravitational mass of the solar system is lower than inferred from its apparent quantity;

I don't understand this; can you explain please?

I should actually have said "gravitational mass ... is different to that inferred", since EM forces could be retarding our motion again the wishes of gravity, not necessarily propelling us faster than we should be going.

What I meant is that we observe a certain amount of matter in a region of the galaxy and infer its mass from what we see. It may be that the quantity of matter is correct but the assumptions we make about its density could be wrong. EM forces could make up for any deficit or excess. Or indeed gravity may be all there needs to be and things get mysteriously denser as you move away from the galactic core, meaning that nothing beyond textbook Relativity is needed other than to explain why densities vary with radial distance.

There are so many variables and so many possible reasons for the "anomaly" that ruling out electricity with today's knowledge of physics is a tad premature.

or (iii) our solar system, perhaps due to its fortuitous location, is less influenced by electricity than the rest of the galaxy; or (iv) gravity really is an electric effect in which case our Sun lying on the cross-over point is not simply coincidence, but expected.

None of these speculations were tested in Peratt's model/simulation, were they? And, as far as I know, no other models - much less simulations - of anything like this exist (at least in published form), do they?

None of them are directly related to Peratt's work. The topic of galaxy rotation velocity curves came up, I posted some basic calculations, and it seems to be going a little off topic (so I'm only intending to respond here to direct questions).

The models don't exist much in astronomy, and they're probably too simplistic to be realistic. The idea was just to see how much force is required and whether it can be plausibly produced by the most basic of electric phenomena (currents flowing in a magnetic field); it turns out that on a galactic scale electricity can meet the requirements for the observed behaviour with such a large margin to spare that it seems implausible that it isn't having a substantial effect.

[Nereid]

Our trusty friend, Wikipedia: http://en.wikipedia.org/wiki/Dark_matter_halo

seb, how could you!

But, assuming for the moment that the figure doesn't horribly distort what's in even the quoted sources, it's inconsistent with your earlier statement ("as it happens, the Sun lies in a cross-over point between that obtained both with and without dark matter"), isn't it?

Undoubtedly, but they do not conform to the theories of gravity, they conform to the equations of gravity.

Sorry, you've completely lost me ... aren't the equations of gravity derived from the theories of gravity?!?

The physical process that gives rise to those equations still remains contentious even in the mainstream.

News to me.

Don't you take the postulates, turn the handle, and out come equations? I mean, the physical processes are nothing but a bit of thinking and putting pen to paper (or cursor/keyboard to computer), aren't they?

I should actually have said "gravitational mass ... is different to that inferred", since EM forces could be retarding our motion again the wishes of gravity, not necessarily propelling us faster than we should be going.

What I meant is that we observe a certain amount of matter in a region of the galaxy and infer its mass from what we see. It may be that the quantity of matter is correct but the assumptions we make about its density could be wrong. EM forces could make up for any deficit or excess. Or indeed gravity may be all there needs to be and things get mysteriously denser as you move away from the galactic core, meaning that nothing beyond textbook Relativity is needed other than to explain why densities vary with radial distance.

If you mean that a vast number of possible ideas - involving gravity, density, matter, electricity, EM forces, ... - have yet to even be thought up, let alone written down in quantitative form and tested, then fine.

There are so many variables and so many possible reasons for the "anomaly" that ruling out electricity with today's knowledge of physics is a tad premature.

No doubt the same thing could be said of invisible pink fairies who delight in mischief, or strange reindeer, or ...

But what do you actually do, on Monday morning, when you get into the office?

So far as I can see, no one is actually working on any ideas like those you've briefly sketched.

None of them are directly related to Peratt's work. The topic of galaxy rotation velocity curves came up, I posted some basic calculations, and it seems to be going a little off topic (so I'm only intending to respond here to direct questions).

Got it.

The models don't exist much in astronomy, and they're probably too simplistic to be realistic. The idea was just to see how much force is required and whether it can be plausibly produced by the most basic of electric phenomena (currents flowing in a magnetic field); it turns out that on a galactic scale electricity can meet the requirements for the observed behaviour with such a large margin to spare that it seems implausible that it isn't having a substantial effect.

Now that conclusion I must have missed! Can you remind me please?

[Goldminer]

Now that conclusion I must have missed! Can you remind me please?

Oh! I dun'no, maybe start here. There are lot's of pictures!

[seb]

Our trusty friend, Wikipedia: http://en.wikipedia.org/wiki/Dark_matter_halo

seb, how could you!

Sorry. It wasn't my fault. Somebody made me do it.

But, assuming for the moment that the figure doesn't horribly distort what's in even the quoted sources, it's inconsistent with your earlier statement ("as it happens, the Sun lies in a cross-over point between that obtained both with and without dark matter"), isn't it?

In what way? It appears that the Sun's velocity lies on both the supposed curve (based on observed mass) and the apparent actual curve, so for the Sun itself its orbit may very well be explained by ordinary gravity with ordinary matter. We can only assume, however, that the Sun is a typical star, and it is clear that many other stars do not have the orbital speeds expected, and assuming the same laws of physics apply everywhere then whatever is causing the "wrong" speeds of the other stars must also be causing the "right" speed of our Sun.

That's why I added the bit about if gravity were electric, etc.

Either way, we can't assume that gravity and matter are alright just because our solar system fits when the rest of the galaxy doesn't. Something somewhere is amiss.

Undoubtedly, but they do not conform to the theories of gravity, they conform to the equations of gravity.

Sorry, you've completely lost me ... aren't the equations of gravity derived from the theories of gravity?!?

Yes and no. The necessary equations were mostly known before a theory to explain them was developed, so anybody developing a theory knew in advance what answer they were seeking. You could argue that Relativity expanded the equations prior to knowing wether the differences were correct, but you could also argue that the equations from Relativity are merely a better fit and not necessarily a reflection of Relativity being closer to reality than other theories.

In other words, the maths arising from the concept of space being distorted by mass gives a very good approximation to the behaviour of gravity, but it does not follow that gravity is caused by the distortion of space by mass.

The physical process that gives rise to those equations still remains contentious even in the mainstream.

News to me.

I would consider the likes of MOND, String Theory, Dark Matter, etc. contentious because they all have their supporters and detractors in the mainstream. I'm sure there are a lot of scientists who accept such things as the best working theory available and use them even when doubting their correctness (as indeed they should).

Don't you take the postulates, turn the handle, and out come equations? I mean, the physical processes are nothing but a bit of thinking and putting pen to paper (or cursor/keyboard to computer), aren't they?

I would accept that the theories of the physical process may be that, but I would argue that the reality of the physical process is necessarily external to thought, maths, and theory (unless you consider maths itself to be incarnate within the nature of the universe).

There are so many variables and so many possible reasons for the "anomaly" that ruling out electricity with today's knowledge of physics is a tad premature.

No doubt the same thing could be said of invisible pink fairies who delight in mischief, or strange reindeer, or ...

Not really. Everybody knows that electricity exists and it is quite well understood.

But what do you actually do, on Monday morning, when you get into the office?

You sound like my boss. Why did they install a coffee machine if they don't want us to use it?

So far as I can see, no one is actually working on any ideas like those you've briefly sketched.

Those ideas were just off the top of my head and very simplified. I don't claim them to be representative of reality, just an example of the lower bounds that the electrical models need to reach.

The models don't exist much in astronomy, and they're probably too simplistic to be realistic. The idea was just to see how much force is required and whether it can be plausibly produced by the most basic of electric phenomena (currents flowing in a magnetic field); it turns out that on a galactic scale electricity can meet the requirements for the observed behaviour with such a large margin to spare that it seems implausible that it isn't having a substantial effect.

Now that conclusion I must have missed! Can you remind me please?

The centripetal force on the Sun is tiny, requiring relatively little moving charge through only weak magnetic fields. The question to my mind is not why should electric currents be there, but why are they not (if they're not)?

[Nereid]

In what way? It appears that the Sun's velocity lies on both the supposed curve (based on observed mass) and the apparent actual curve, so for the Sun itself its orbit may very well be explained by ordinary gravity with ordinary matter. We can only assume, however, that the Sun is a typical star, and it is clear that many other stars do not have the orbital speeds expected, and assuming the same laws of physics apply everywhere then whatever is causing the "wrong" speeds of the other stars must also be causing the "right" speed of our Sun.

Well, then perhaps this is more apt? "as it happens, some Milky Way stars - but not the Sun - lie in a cross-over point between that obtained both with and without dark matter"

Either way, we can't assume that gravity and matter are alright just because our solar system fits when the rest of the galaxy doesn't. Something somewhere is amiss.

What parts of the Milky Way are you referring to ("the rest of the galaxy doesn't")? If I recall correctly (and I may well not!), you have to go quite a few kpc further from the centre before you get a clear mismatch between observed velocities (actually inferred, in most cases) and what you'd expect based solely on gravity and estimated stars, gas, plasma, and dust closer to the nucleus.

Yes and no. The necessary equations were mostly known before a theory to explain them was developed, so anybody developing a theory knew in advance what answer they were seeking. You could argue that Relativity expanded the equations prior to knowing wether the differences were correct, but you could also argue that the equations from Relativity are merely a better fit and not necessarily a reflection of Relativity being closer to reality than other theories.

In other words, the maths arising from the concept of space being distorted by mass gives a very good approximation to the behaviour of gravity, but it does not follow that gravity is caused by the distortion of space by mass.

Cue one of my fave topics! The relationship between physics (and physics theories) and 'reality'.

Not really. Everybody knows that electricity exists and it is quite well understood.

Yep ... and no one has - yet! - been able to show that it plays any significant role in the observational signatures (that we call, in shorthand, 'rotation curves'), other than with respect to those signatures being written entirely in electromagnetic radiation. In fact, the one (and only?) attempt to do so - Peratt's, that we are discussing in this thread - seems inconsistent with those signatures, doesn't it?

The centripetal force on the Sun is tiny, requiring relatively little moving charge through only weak magnetic fields. The question to my mind is not why should electric currents be there, but why are they not (if they're not)?

Ah, I see; thanks.

Well, the magnetic field strengths - and, in some cases, directions too - have been estimated, haven't they? Given those (ballpark) values, what would the charge on the Sun have to be to produce the estimated force?

[seb]

In what way? It appears that the Sun's velocity lies on both the supposed curve (based on observed mass) and the apparent actual curve, so for the Sun itself its orbit may very well be explained by ordinary gravity with ordinary matter. We can only assume, however, that the Sun is a typical star, and it is clear that many other stars do not have the orbital speeds expected, and assuming the same laws of physics apply everywhere then whatever is causing the "wrong" speeds of the other stars must also be causing the "right" speed of our Sun.

Well, then perhaps this is more apt? "as it happens, some Milky Way stars - but not the Sun - lie in a cross-over point between that obtained both with and without dark matter"

I'm wondering if we are at cross-purposes here. I'm assuming that the graph in the Wikipedia article reflects accepted observations and calculations, since Wikipedia has that reputation. What I'm trying to say is that the plotted graphs of the observed velocities and the calculated velocities cross over at about the same place as where the Sun sits (~9 kpc).

Either way, we can't assume that gravity and matter are alright just because our solar system fits when the rest of the galaxy doesn't. Something somewhere is amiss.

What parts of the Milky Way are you referring to ("the rest of the galaxy doesn't")? If I recall correctly (and I may well not!), you have to go quite a few kpc further from the centre before you get a clear mismatch between observed velocities (actually inferred, in most cases) and what you'd expect based solely on gravity and estimated stars, gas, plasma, and dust closer to the nucleus.

The graphs and explanations I've seen seem to have differences in velocity almost straight away as you get out of the core. In the halo article for instance, there are discrepancies at only one kpc. Are the Wikipedia articles wrong?

Not really. Everybody knows that electricity exists and it is quite well understood.

Yep ... and no one has - yet! - been able to show that it plays any significant role in the observational signatures (that we call, in shorthand, 'rotation curves'), other than with respect to those signatures being written entirely in electromagnetic radiation. In fact, the one (and only?) attempt to do so - Peratt's, that we are discussing in this thread - seems inconsistent with those signatures, doesn't it?

It would seem that it's not entirely inconsistent because there's enough people arguing about it.

The centripetal force on the Sun is tiny, requiring relatively little moving charge through only weak magnetic fields. The question to my mind is not why should electric currents be there, but why are they not (if they're not)?

Ah, I see; thanks.

Well, the magnetic field strengths - and, in some cases, directions too - have been estimated, haven't they? Given those (ballpark) values, what would the charge on the Sun have to be to produce the estimated force?

The charge is not the important quantity. We are talking here about currents in magnetic fields. I'm sure you know the formulae. If we consider the current only as flowing across the heliopause (say 200AU diameter), ignoring even that flowing between stars, then to get a 3.2e20N centripetal force with a magnetic field of 1nT the current need only be about 1e16A. This is a quarter of that supposed by Scott, so it is in the same order of magnitude as his electric star idea. Assuming I haven't put the wrong numbers into my calculator... It will of course be complicated by the current flowing in different directions in different places, and I'm assuming that the field is always perpendicular; that won't always be the case.

But, even better than that! That is the current and field needed to produce a force to move the entire sun. As shown previously, you may be able to get away with acting on a tiny fraction of it. Somewhere around a millionth to a billionth would probably suffice. That could give you a current of as little as 10MA, or something not unfamiliar to the National Grid. In other words, a single decent power station could be sufficient to change the trajectory of the entire solar system. The logistics of the cabling notwithstanding, obviously.

That seems a rather interesting conclusion. I wonder if it would be sufficient to just move a small fraction of the Sun? It looks a bit too easy for comfort. I'll have a look at the maths some time. At this rate we'll soon have the Sun being powered by a PP3 (with which you could account for the lithium discrepancies too). Failing that, scrap the power station idea.

[Nereid]

I'm wondering if we are at cross-purposes here. I'm assuming that the graph in the Wikipedia article reflects accepted observations and calculations, since Wikipedia has that reputation. What I'm trying to say is that the plotted graphs of the observed velocities and the calculated velocities cross over at about the same place as where the Sun sits (~9 kpc).

The graphs and explanations I've seen seem to have differences in velocity almost straight away as you get out of the core. In the halo article for instance, there are discrepancies at only one kpc. Are the Wikipedia articles wrong?

We may indeed be at cross-purposes.

Perhaps this might help: at what galactocentric radius (i.e. distance from the centre of the MW) do models of the galaxy - built to account for relevant observations of the motions of MW stars, gas, plasma, and dust - require a CDM component in order to account for those observations (to within the estimated uncertainties)?

The question goes back to Oort, who beat Zwicky to the punch in proposing (in 1930?) that 'dark matter' (which is not quite the same as the CDM of today) is necessary to account for the observed motions of stars in the Sun's neighbourhood. Later observations - a lot more faint stars than Oort had assumed, if I recall correctly - removed the need for any dark matter, a situation which remains the case today.

A quite different question is something like 'what is the estimated density (in kg per cubic parsec, say) of CDM at ~8 kpc, based on NFW/isothermal/whatever models?' As far as I know, such answers are consistent with 'we can't see the signature of CDM, in the observed motions of stars etc, in the central ~8 kpc of the galaxy'.

More generally, in spiral galaxies the contribution of CDM to rotation curves is 'in the noise' until you get quite some way out in the disk. The same is true of ellipticals, except that the signature is 'velocity dispersion' not 'rotation velocity'. However, strong lensing observations are consistent with CDM models ... but their 'spatial resolution' (if I may call it that) is quite poor.

The charge is not the important quantity. We are talking here about currents in magnetic fields. I'm sure you know the formulae. If we consider the current only as flowing across the heliopause (say 200AU diameter), ignoring even that flowing between stars, then to get a 3.2e20N centripetal force with a magnetic field of 1nT the current need only be about 1e16A.

Perhaps.

However, in this case you'd need to look at the net force on a chunk of heliosphere wouldn't you, not the Sun?

After all, observed acceleration can be associated with net force only, right?

This is a quarter of that supposed by Scott, so it is in the same order of magnitude as his electric star idea. Assuming I haven't put the wrong numbers into my calculator... It will of course be complicated by the current flowing in different directions in different places, and I'm assuming that the field is always perpendicular; that won't always be the case.

But, even better than that! That is the current and field needed to produce a force to move the entire sun.

This is the part I don't understand (and I didn't understand it when you first posted it).

Can you explain it again please, in terms of the net force acting on the Sun?

[seb]

Perhaps this might help: at what galactocentric radius (i.e. distance from the centre of the MW) do models of the galaxy - built to account for relevant observations of the motions of MW stars, gas, plasma, and dust - require a CDM component in order to account for those observations (to within the estimated uncertainties)?

"Require" is too strong a term, IMHO. Only the CDM model could ever require it, and if it doesn't then fine, but other models that can find a way to fit using other means (e.g. modified gravity or electricity) don't require it at all.

The question goes back to Oort, who beat Zwicky to the punch in proposing (in 1930?) that 'dark matter' (which is not quite the same as the CDM of today) is necessary to account for the observed motions of stars in the Sun's neighbourhood. Later observations - a lot more faint stars than Oort had assumed, if I recall correctly - removed the need for any dark matter, a situation which remains the case today.

Within the Sun's neighbourhood, yes, at least. If there is evidence that stars nearer the galactic core don't need dark matter to explain their orbits then it would seem that there are some discrepancies in the published claims. That graph on Wikipedia's page about the galactic halo (also used on some other pages) has quite small error bars around the 4kpc region, with a big difference in speed between expected and observed. Texts claim the CDM to start at around 30kpc, yet the numbers show a speed discrepancy from around 1kpc. If CDM on the outside of a star's orbit is unable to influence its orbital speed, then what is the purpose of the galactic dark-matter halo?

However, in this case you'd need to look at the net force on a chunk of heliosphere wouldn't you, not the Sun?

After all, observed acceleration can be associated with net force only, right?

Yes. The calculation assumes that the bulk of the mass of the heliosphere resides in the sun and the sun is at the centre of it.

This is a quarter of that supposed by Scott, so it is in the same order of magnitude as his electric star idea. Assuming I haven't put the wrong numbers into my calculator... It will of course be complicated by the current flowing in different directions in different places, and I'm assuming that the field is always perpendicular; that won't always be the case.

But, even better than that! That is the current and field needed to produce a force to move the entire sun.

This is the part I don't understand (and I didn't understand it when you first posted it).

Can you explain it again please, in terms of the net force acting on the Sun?

Obviously the net force has to be the full 3.2e20N, because you need to apply a centripetal acceleration to the entire contents of the heliosphere (which as I said above I am approximating that as being the sun in terms of mass and centre). For that you need the entire 1e16A flowing through the sun, but it only needs to act on a small amount such that that amount is forced to orbit the galaxy at the observed speeds. Because the centripetal acceleration is so small compared to the self-gravity of the sun, the bulk of it could follow gravitationally.

Now, obviously, (I say obviously because I don't want anyone to get carried away with the power station theory), the smaller the amount of charged matter pulled electrically then the greater its centripetal acceleration needs to be because the sun's self-gravity and tangential momentum will try to pull it off course. I haven't done the maths on how much you need to pull electrically, but my gut feeling is that something on the order of 10%~20% would suffice.

Imagine, as an example, that the force is acting on only half of the sun (it won't act on any uncharged particles). This will apply a centripetal force of 6.4e20N to that half. Assuming a worst-case of no gravitational force acting on the Sun, then its tangential momentum will equate to 3.2e20N outwards, giving a net force of 3.2e20N towards the galactic centre. As long as the gravitational force between the two parts of the Sun exceeds 3.2e20N (which it will, by a considerable margin) then thy Sun shall not be cleft in twain. The whole thing will go around the galactic core in tandem with the electric current.

You still need the full 1e16A, however. And this, of course, to repeat myself, is only a very simplistic calculation using little more than the Lorentz force and not directly derived from any models of Peratt, Scott, Thornhill, et al., but is it not surprising how well the numbers add up?

At least some, if not most, models of electric stars have current flowing into both poles, i.e. in opposite directions, and then out of the equator. The calculations I've done above assume a net current in one direction (with the solar wind probably being just a leakage current), and so whether they apply and what modifications are needed would depend a lot on what is going on in the interstellar medium.

[Nereid]

"Require" is too strong a term, IMHO. Only the CDM model could ever require it, and if it doesn't then fine, but other models that can find a way to fit using other means (e.g. modified gravity or electricity) don't require it at all.

Quite right; I should have qualified "models" appropriately.

Within the Sun's neighbourhood, yes, at least. If there is evidence that stars nearer the galactic core don't need dark matter to explain their orbits then it would seem that there are some discrepancies in the published claims.

Actually, I think it's more likely a case of too radical a summary of the relevant papers, or a misreading of them ... but if you find anything that you consider to be a discrepancy ...

That graph on Wikipedia's page about the galactic halo (also used on some other pages) has quite small error bars around the 4kpc region, with a big difference in speed between expected and observed. Texts claim the CDM to start at around 30kpc, yet the numbers show a speed discrepancy from around 1kpc.

Please, let's look at the primary sources by all means; but let's agree that, when it comes to checking things out properly, Wikipedia is an unreliable - and hence unacceptable - source, shall we?

If CDM on the outside of a star's orbit is unable to influence its orbital speed, then what is the purpose of the galactic dark-matter halo?

In another thread, something called "Gauss's law" came up (it actually came up earlier in this thread too, but not by name); if it's distributed with the appropriate symmetry, matter 'external' (i.e. at greater Galactocentric radii) to a star is indeed "unable to influence its orbital speed"!

Yes. The calculation assumes that the bulk of the mass of the heliosphere resides in the sun and the sun is at the centre of it.

I think the actual number is >99%; in other words, only at the ~1% level does the entire mass of the solar system outside the Sun count.

Obviously the net force has to be the full 3.2e20N, because you need to apply a centripetal acceleration to the entire contents of the heliosphere (which as I said above I am approximating that as being the sun in terms of mass and centre). For that you need the entire 1e16A flowing through the sun, but it only needs to act on a small amount such that that amount is forced to orbit the galaxy at the observed speeds. Because the centripetal acceleration is so small compared to the self-gravity of the sun, the bulk of it could follow gravitationally.

Switching from "the Sun" to the solar system barycentre makes it more accurate; the entire solar system can be modelled as a ~1.00x sol point mass (0 < x < ~5?) at the barycentre.

Now, obviously, (I say obviously because I don't want anyone to get carried away with the power station theory), the smaller the amount of charged matter pulled electrically then the greater its centripetal acceleration needs to be because the sun's self-gravity and tangential momentum will try to pull it off course. I haven't done the maths on how much you need to pull electrically, but my gut feeling is that something on the order of 10%~20% would suffice.

Here's where I begin to not follow you.

Imagine, as an example, that the force is acting on only half of the sun (it won't act on any uncharged particles). This will apply a centripetal force of 6.4e20N to that half. Assuming a worst-case of no gravitational force acting on the Sun, then its tangential momentum will equate to 3.2e20N outwards, giving a net force of 3.2e20N towards the galactic centre. As long as the gravitational force between the two parts of the Sun exceeds 3.2e20N (which it will, by a considerable margin) then thy Sun shall not be cleft in twain. The whole thing will go around the galactic core in tandem with the electric current.

I don't follow this; let's if it's relevant in any case ...

You still need the full 1e16A, however. And this, of course, to repeat myself, is only a very simplistic calculation using little more than the Lorentz force and not directly derived from any models of Peratt, Scott, Thornhill, et al., but is it not surprising how well the numbers add up?

OK, time to consider what the Lorentz force is acting on.

In Peratt's model, there is a pair of field aligned (Birkeland) currents, in the form of plasma filaments. In the paper, the forces are given in analytic form, together with a description of the appropriate regime in which the approximation is valid; as I read it, your application is way way beyond the relevant bounds - the Sun is not, for example, a thin plasma filament!

In his simulations, as described in his book, the complex behaviour of the plasmas is reproduced by making some simplifying assumptions; the plasma is assumed to be comprised of (charged) 'particles', for example, which interact with, and produce, magnetic and electric fields - again, the kind of thing you're describing is similar to Peratt's simulations in hardly any way at all.

So perhaps you could describe, in some more detail, what the players in your model are? What is the current, for example, and what is the Lorentz force acting on?

At least some, if not most, models of electric stars have current flowing into both poles, i.e. in opposite directions, and then out of the equator. The calculations I've done above assume a net current in one direction (with the solar wind probably being just a leakage current), and so whether they apply and what modifications are needed would depend a lot on what is going on in the interstellar medium.

Indeed ... and you also need to get the direction right too! The rotation axis of the Sun does not have any particularly nice angle to the direction to the galaxy centre, or to the solar system barycentre's estimated direction of motion with respect to the nearby stars, or ...

[mharratsc]

In an electric discharge through particulates, Marklund convection draws in surrounding matter. This matter seems to aggregate at pinches where it forms spheres. This was demonstrated by C.J. Ransom in his 'Martian Blueberry' experiment in hematite.

The point is- the current was the main player in the experiment- the matter accumulating at the pinch was a side effect. It is possible therefore that the Sun, our planets, and all other matter within our heliosphere are 'side effects' of the intragalactic current & plasma filament within which we reside (as extraordinary as that may sound against the backdrop of mainstream cosmology.)

Of course, I have no quantitative data regarding any of this, in case anyone is interested in that sort of stuff...

[Aristarchus]

Please, let's look at the primary sources by all means; but let's agree that, when it comes to checking things out properly, Wikipedia is an unreliable - and hence unacceptable - source, shall we?

Still trying to validate your knowledge of information literacy through simply offering what amounts to a directive. Arguments presented prior on this forum simply don't vanish or disappear because you refuse to oblige them with a "proper" response, or fail to provide a response at all.

Wikipedia is a valid source for those that can properly discern the information within it, as with any encyclopedia, it make mistakes and republishes new information when afforded the opportunity. Wikipedia also clarifies that a page regarding a particular topic is not well enough vetted to establish it as a significant authority; whereas, traditional encyclopedias rely on few authors of authority, and often take several years for re-vetting the information from a previous publication.

The site Wikipedia offers comments and discussions concerning its entries, given that the authority of a page might be in question. Wikipedia also allows users to red flag information that might be construed as incorrect by other users. The comments regarding Wikipedia, as evidenced on this forum, is that it often caters to the mainstream establishment regarding the sciences, and it thus suffers from the same plight we see in academia and universities. And yet, time and again you are unwilling to admit to the veracity or even an articulation of a premise as posited here on the TB forum.

In addition, not sure you have specified what constitutes a "primary source," but Wikipedia provides bibliographic citations at the bottom of its pages in the "notes" section, and it also supplies parenthetical/bracketed citation number links in the form of endnotes to access those references in an expedited manner. Wikipedia also provides a "further reading" section for sourcing materials - for example - and this might save you the trouble of persistently asking your fellow TB forum members for sourced material, which you could easily ascertain yourself:

Plasma cosmology. (2011, January 10). In Wikipedia, The Free Encyclopedia. Retrieved 16:35, February 1, 2011, from http://en.wikipedia.org/w/index.php?tit ... =407030930

Notes

1.^ a b c Hannes Alfvén, "On hierarchical cosmology" (1983) Astrophysics and Space Science (ISSN 0004-640X), vol. 89, no. 2, January 1983, p. 313-324.
2.^ It is described as such by advocates and critics alike. In the February 1992 issue of Sky & Telescope ("Plasma Cosmology"), Anthony Peratt describes it as a "nonstandard picture". The open letter at http://www.cosmologystatement.org – which has been signed by Peratt and Lerner – notes that "today, virtually all financial and experimental resources in cosmology are devoted to big bang studies". The ΛCDM model big bang picture is typically described as the "concordance model", "standard model" or "standard paradigm" of cosmology here, and here.
3.^ Helge S. Kragh, Cosmology and Controversy: The Historical Development of Two Theories of the Universe, 1996 Princeton University Press, 488 pages, ISBN 069100546X (pp.482-483)
4.^ Alfven, Hannes O. G., "Cosmology in the plasma universe - an introductory exposition", IEEE Transactions on Plasma Science (ISSN 0093-3813), vol. 18, Feb. 1990, p. 5-10.
5.^ Plasma cosmology advocates Anthony Peratt and Eric Lerner, in an open letter cosigned by a total of 34 authors, state "An open exchange of ideas is lacking in most mainstream conferences", and "Today, virtually all financial and experimental resources in cosmology are devoted to big bang studies". [1]
6.^ Tom Van Flandern writes in The Top 30 Problems with the Big Bang, "For the most part, these four alternative cosmologies [including Plasma Cosmology] are ignored by astronomers."
7.^ Colafrancesco, S. and Giordano, F. The impact of magnetic field on the cluster M - T relation Astronomy and Astrophysics, Volume 454, Issue 3, August II 2006, pp. L131-L134. [2] recount: "Numerical simulations have shown that the wide-scale magnetic fields in massive clusters produce variations of the cluster mass at the level of ~ 5 − 10% of their unmagnetized value.... Such variations are not expected to produce strong variations in the relative [mass-temperature] relation for massive clusters."
8.^ See for example: Dekel, A. and Silk, J. The origin of dwarf galaxies, cold dark matter, and biased galaxy formation Astrophysical Journal, Part 1 (ISSN 0004-637X), vol. 303, April 1, 1986, p. 39-55.[3] where they model plasma processes in galaxy formation that is driven primarily by gravitation of cold dark matter.
9.^ H. Alfvén and C.-G. Falthammar, Cosmic electrodynamics (2nd edition, Clarendon press, Oxford, 1963). "The basic reason why electromagnetic phenomena are so important in cosmical physics is that there exist celestial magnetic fields which affect the motion of charged particles in space.... The strength of the interplanetary magnetic field is of the order of 10-4 gauss (10 nanoteslas), which gives the [ratio of the magnetic force to the force of gravity] ≈ 107. This illustrates the enormous importance of interplanetary and interstellar magnetic fields, compared to gravitation, as long as the matter is ionized." (p.2-3)
10.^ a b P. J. E. Peebles, Principles of Physical Cosmology, (1993) Princeton University Press, p. 207, ISBN 978-0691074283
11.^ Alfvén, H.; Carlqvist, P., "Interstellar clouds and the formation of stars" Astrophysics and Space Science, vol. 55, no. 2, May 1978, p. 487-509.
12.^ http://adsabs.harvard.edu/abs/2006astro.ph..9031S
13.^ Hannes Alfven, Cosmic plasma. Taylor & Francis US, 1981,IV.10.3.2, p.109. "Double layers may also produce extremely high energies. This is known to take place in solar flares, where they generate solar cosmic rays up to 10^9 to 10^10 eV."
14.^ Alfvén, H., "Double layers and circuits in astrophysics", (1986) IEEE Transactions on Plasma Science (ISSN 0093-3813), vol. PS-14, Dec. 1986, p. 779-793. Based on the NASA sponsored conference "Double Layers in Astrophysics" (1986)
15.^ H. Alfvén and C.-G. Falthammar, Cosmic electrodynamics (Clarendon press, Oxford, 1963). H. Alfvén, Worlds-antiworlds: antimatter in cosmology, (Freeman, 1966). O. Klein, "Arguments concerning relativity and cosmology," Science 171 (1971), 339.
16.^ Hannes Alfvén, "Has the Universe an Origin" (1988) Trita-EPP, 1988, 07, p. 6. See also Anthony L. Peratt, "Introduction to Plasma Astrophysics and Cosmology" (1995) Astrophysics and Space Science, v. 227, p. 3-11: "issues now a hundred years old were debated including plasma cosmology's traditional refusal to claim any knowledge about an 'origin' of the universe (e.g., Alfvén, 1988).
17.^ Alfvén, Hannes, "Cosmology: Myth or Science?" (1992) IEEE Transactions on Plasma Science (ISSN 0093-3813), vol. 20, no. 6, p. 590-600. See also [4]
18.^ (See IEEE Transactions on Plasma Science, issues in 1986, 1989, 1990, 1992, 2000, 2003, and 2007 Announcement 2007 here)
19.^ See e.g. P. J. E. Peebles, Large-scale structure of the universe (Princeton, 1980).
20.^ See, for example, the Virgo Consortium's large-scale simulation of "universes in boxes" with the largest voids reaching such sizes. See also F. Hoyle and M. S. Vogeley, Voids in the 2dF galaxy redshift survey, Astrophys. J. 607, 751–764 (2004) arXiv:astro-ph/0312533.
21.^ See e.g. M. Bartelmann and P. Schneider, Weak gravitational lensing, Phys. Rept. 340 291–472 (2001) arXiv:astro-ph/9912508.
22.^ P. J. E. Peebles, Principles of Physical Cosmology (Princeton, 1993). P. J. E. Peebles, Large-scale structure of the universe (Princeton, 1980).
23.^ M. Tegmark et al. (SDSS collaboration), "The three-dimensional power spectrum of galaxies from the Sloan Digital Sky Survey", Astrophysical J. 606 702–740 (2004). arXiv:astro-ph/0310725 The failure of alternative structure formation models is clearly indicated by the deviation of the matter power spectrum from a power law at scales larger than 0.5 h Mpc-1 (visible here).The authors comment that their work has "thereby [driven] yet another nail into the coffin of the fractal universe hypothesis..."
24.^ J.Audouze et al.', Big Bang Photosynthesis and Pregalactic Nucleosynthesis of Light Elements, 'Astrophysical Journal 293:L53-L57, 1985 June 15[5]
25.^ Epstein et al., The origin of deuterium, Nature, Vol. 263, September 16, 1976 point out that if proton fluxes with energies greater than 500 MeV were intense enough to produce the observed levels of deuterium, they would also produce about 1000 times more gamma rays than are observed.
26.^ Ref. 10 in "Galactic Model of Element Formation" (Lerner, IEEE Trans. Plasma Science Vol. 17, No. 2, April 1989 [6]) is J.Audouze and J.Silk, "Pregalactic Synthesis of Deuterium" in Proc. ESO Workshop on "Primordial Helium", 1983, pp. 71-75[7] Lerner includes a paragraph on "Gamma Rays from D Production" in which he claims that the expected gamma ray level is consistent with the observations. He cites neither Audouze nor Epstein in this context, and does not explain why his result contradicts theirs.
27.^ D. N. Spergel et al. (WMAP collaboration), "First year Wilkinson Microwave Anisotropy Probe (WMAP) observations: Determination of cosmological parameters", Astrophys. J. Suppl. 148 (2003) 175.

Further reading

Alfvén, Hannes: "On hierarchical cosmology", Astrophysics and Space Science (ISSN 0004-640X), vol. 89, no. 2, Jan. 1983, p. 313-324. (1983)

"Cosmology in the plasma universe". (1988) Laser and Particle Beams (ISSN 0263-0346), vol. 6, Aug. 1988, p. 389-398. Full text

"Model of the plasma universe", IEEE Transactions on Plasma Science (ISSN 0093-3813), vol. PS-14, Dec. 1986, p. 629-638 Full text (PDF)

Peratt, Anthony: "Evolution of the plasma universe. I - Double radio galaxies, quasars, and extragalactic jets", IEEE Transactions on Plasma Science (ISSN 0093-3813), vol. PS-14, Dec. 1986, p. 639-660. Full text (PDF)

"Evolution of the plasma universe. II - The formation of systems of galaxies", IEEE Transactions on Plasma Science (ISSN 0093-3813), vol. PS-14, Dec. 1986, p. 763-778. Full text (PDF)

"The role of particle beams and electrical currents in the plasma universe", Peratt, Anthony L., Laser and Particle Beams (ISSN 0263-0346), vol. 6, Aug. 1988, p. 471-491 Full text (PDF)

Wright, E. L. "Errors in "The Big Bang Never Happened"". See also: Lerner, E. J. "Dr. Wright is Wrong". Lerner's reply to the above.

IEEE Xplore, IEEE Transactions on Plasma Science, 18 issue 1 (1990), Special Issue on Plasma Cosmology including A. L. Peratt, "Plasma cosmology", IEEE T. Plasma Sci. 18, 1-4 (1990).

Various authors: "Introduction to Plasma Astrophysics and Cosmology", Astrophysics and Space Science, v. 227 (1995) p. 3-11. Proceedings of the Second IEEE International Workshop on Plasma Astrophysics and Cosmology, held from 10 to 12 May 1993 in Princeton, New Jersey

H. Alfvén, Worlds-antiworlds: antimatter in cosmology, (Freeman, 1966).

H. Alfvén, Cosmic Plasma (Reidel, 1981) ISBN 90-277-1151-8

E. J. Lerner, The Big Bang Never Happened, (Vintage, 1992) ISBN 0-679-74049-X

A. L. Peratt, Physics of the Plasma Universe, (Springer, 1992) ISBN 0-387-97575-6