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

[Nereid]

Hi Nereid,

May I ask - mharratsc (and nick c) - what posts, by Nereid, in that JREF thread were the source of, or trigger for, your comments?

In response to:

It is easy to win the game when you make the rules. It is big time professional wrestling as opposed to the Olympic variety.
Nick

Sorry that you did not understand my metaphor, I thought that the analogy would be clear to most of the participants of this forum. My comment is not referring to any specific post, but rather to the set up of the JREF, in a general sense. It would apply to BAUT forum as well. It is a comment directed to paradigm change and the reliance on the peer review system.
In professional wrestling the outcomes are preordained by the system, whereas, Olypmic wrestling is competitive.
I like the metaphor, but I am not going to get into an over analysis of the validity of the metaphor. It is an opinion on my part, one which I still hold.

Nick

Returning to this post ...

Could you elaborate a bit please?

What do you see as 'the game' ("It is easy to win the game when you make the rules")?

And how do the rules of BAUT (and JREF) stack the deck (so to speak)?

[nick c]

Nereid,

Could you elaborate a bit please?

What do you see as 'the game' ("It is easy to win the game when you make the rules")?

And how do the rules of BAUT (and JREF) stack the deck (so to speak)?

Perhaps you should ask (if the deck is stacked) those that have posted or attempted to post EU ideas on those forums? For example in the "Against the Mainstream" board on BAUT.
Meanwhile I will stick with what I wrote in my previous post:

I like the metaphor, but I am not going to get into an over analysis of the validity of the metaphor. It is an opinion on my part, one which I still hold.

Nick

[Grits]

I dunno if Siggy or someone else posted this dialogue or not, but... Nereid is at it again with his/her/it's little cronies on the JREF Forums...

heh...I don't know why this surprises me, particularly after I've just responded to some of this person's posts with near incredulity.

[Grits]

May I ask - mharratsc (and nick c) - what posts, by Nereid, in that JREF thread were the source of, or trigger for, your comments?

Many of us would appreciate it if you'd quote somewhat less than 100% of a post if you only intend to add a few lines at the end. You have a noise to signal ratio of about 50:1 there, if we could get the noise level down in this forum it would probably allow for more fruitful conversation between the users.

[Nereid]

May I ask - mharratsc (and nick c) - what posts, by Nereid, in that JREF thread were the source of, or trigger for, your comments?

Many of us would appreciate it if you'd quote somewhat less than 100% of a post if you only intend to add a few lines at the end. You have a noise to signal ratio of about 50:1 there, if we could get the noise level down in this forum it would probably allow for more fruitful conversation between the users.

Thanks for your comment Grits.

As you know, I am a newcomer here, and am still learning the ropes. I see that there's an item in the guidelines similar to your comment; however, in my reading of many of the threads in this forum, I also see that there are many posts which are just like the ones of mine you are commenting on. In any case, I shall try to be more careful to quote just the part of a post that is relevant to my response from now on.

Taking nick c at his word ("Perhaps you should ask (if the deck is stacked) those that have posted or attempted to post EU ideas on those forums? For example in the "Against the Mainstream" board on BAUT."), may I ask if you have had such an experience?

[Nereid]

In the EU position wrt fundamental physics thread, seb wrote:

I'm not aware of any unexpected quantitative successes that match the depth and scope of mainstream astronomy, but that is only where the current state of theoretical development currently is. If electricity and plasma are as pervasive as believed by EU/PC then the quantitative analysis will become developed, as indeed it must. Discoveries often come in spurts, and recently there have been many observational vindications of the qualitative expectations of EU/PC which are the first steps towards quantitative analysis.

One quantitative "success" that springs to mind is the rotation velocity curves of galaxies. That matches well with the mathematics of plasma, but very badly with the gravity of observed mass. However, it still lacks the fundamental measurement of whether the necessary currents are really there.

This sparked some discussion, which is really off-topic for that thread. Siggy_G recommended that discussion of Peratt's work on this topic be continued in a separate thread, and I think this established thread is appropriate.

Peratt's published papers relevant to "the rotation velocity curves of galaxies" are essentially only two, namely "Evolution of the Plasma Universe: I. Double Radio Galaxies, Quasars, and Extragalactic JetsEvolution of the Plasma Universe: I. Double Radio Galaxies, Quasars, and Extragalactic Jets" and "Evolution of the Plasma Universe: II. The Formation of Systems of Galaxies". Peratt myself cites one or both these in several subsequent papers - for example, "The role of particle beams and electrical currents in the plasma universe", a review paper - but as far as I know there is nothing new in any of them (of course these later papers by Peratt are interesting, and do contain new material, but not on "the rotation velocity curves of galaxies").

Peratt's book, Physics of the Plasma Universe, Springer 1991 (ISBN 978-0387975757), provides details of some of the key background to his two 1986 papers, including the PIC code.

[Siggy_G]

Nereid said: Stars have very different net charge to mass ratios than the particles in Peratt's plasma experiments and simulations.

Contrary to what many think, Peratt's simulations and work related to galaxy formations isn't about how stars form into spiral galaxy formations at all. Stars aren't the equivalent of the dust particles in the experiements/simulations. Dust particles in the experiments/simulations are the equivalent of dust particles in a galaxy.

Peratt's work is about how galactic sized dusty plasma filaments form and rotate, and how electromagnetic dynamics play the most important role in this regard. This gives the basis for both the overall formation and angular momentum of the galaxy. The later condensation from dusty plasma into larger structure like stars (as he elaborates on), is not in breach of the angular momentum built up in the galaxy overall. Therefore it does interestingly explain these observed non-Keplerian rotation velocities without the need for dark matter as with the standard gravity-/matter-only driven model. Peratt's model also explains in a better way why galaxies and stars tend to form along like droplets on a spiderweb string.

[Nereid]

Nereid said: Stars have very different net charge to mass ratios than the particles in Peratt's plasma experiments and simulations.

But Peratt's simulations and work related to galaxy formations, isn't about how stars form into spiral galaxy formations at all.

Indeed.

However, the rotation curves of (at least some) spiral galaxies can be - and have been - derived from analysis of features in their spectra attributed to the light emitted by stars.

The later condensation from dusty plasma into larger structure like stars (as he elaborates on), is not in breach of the angular momentum built up in the galaxy overall.

Using just Newtonian dynamics for now, every object in a state of uniform motion tends to remain in that state of motion unless an external force is applied to it. So, once formed, stars will move in 'straight' lines, at the speeds they had (relative to the centre of mass/nucleus of the galaxy they are in) when they were formed ... unless they are acted upon by a force (or, more precisely, a non-zero net external force).

One thing they will not do, unless acted upon by a non-zero net external force, is move around the nucleus in approximately circular orbits (centered on that nucleus).

How, then, to account for the motions of stars in spiral galaxies, in Peratt's model?

[Siggy_G]

One thing they will not do, unless acted upon by a non-zero net external force, is move around the nucleus in approximately circular orbits (centered on that nucleus).

How, then, to account for the motions of stars in spiral galaxies, in Peratt's model?

According to the model, when matter is condensed into larger structures (stars), gravity from the collective and central mass will take over and play an important role. That explains the centripetal acceleration towards the galaxy nucleus - i.e. the non-zero external force that keeps being applied to the surrounding stars.

The orbital (tangential) velocity the stars have, was defined at the initial state when the stars still were a dusty plasma, where the bulk movement was a product of twisting Birkeland currents. (Here's why dark matter isn't needed to explain the non-Keplerian rotational velocity). Volumes of matter condense, still having the same bulk movement, and gravity maintains the centripetal acceleration.

[Nereid]

According to the model, when matter is condensed into larger structures (stars), gravity from the collective and central mass will take over and play an important role. That explains the centripetal acceleration towards the galaxy nucleus - i.e. the non-zero external force that keeps being applied to the surrounding stars.

None of this is actually modelled, is it? I mean, per either of the 1986 papers, or the book.

Certainly Peratt indicates that the simulation can be extended to include this, and other, aspects (lab experiments with plasmas can't incorporate gravity at this level, can it); however, as far as I know he didn't actually publish the results of any such extensions, right? If you know of any publications which report the results of such simulations, please cite them.

The orbital (tangential) velocity the stars have, was defined at the initial state when the stars still were a dusty plasma, where the bulk movement was a product of twisting Birkeland currents. (Here's why dark matter isn't needed to explain the non-Keplerian rotational velocity). Volumes of matter condense, still having the same bulk movement, and gravity maintains the centripetal acceleration.

At the qualitative level that sounds somewhat plausible; however, no one has actually done any modelling on this, have they? I mean, in the sense of publishing something that is objective, and independently verifiable (at least in principle).

In any case, once stars form they will quickly migrate to orbits determined by the total mass interior to those orbits (approximately), assuming that the only significant net force acting on them is gravitation ... and that brings us right back to the original need for dark matter (whether baryonic or not), i.e. the mass implied by their orbits is greater than the estimated total in gas/plasma, dust, and stars, and this 'mass gap' increases with distance from the galactic nucleus.

The challenge - for Peratt's model - with regard to elliptical ('early type') galaxies is somewhat different (there is, for example, essentially no gas/plasma or dust in such galaxies, yet the stars seem to be moving far too fast to be where they are if the only significant net force acting on them is the gravitation of other stars), but no less acute.

[seb]

Here are some back-of-the-envelope calculations regarding the rotations of stars in a galaxy. (The calculations make some simplistic assumptions and are only intended to explore the order-of-magnitude reasonableness of the ideas for discussion, not to provide a rigorous solution.)

The qualitative model I'm assuming is thus: intergalatic plasma currents twist around each other; this acts on intragalactic currents, making them turn around the centre with the observed velocities; the intragalactic currents are those responsible for pinching down into stars and forming heliospheres; as the currents move, so too do the stars along their lengths. Neutral matter within the stars are gravitationally bound to the ionised matter, thus also moving with the currents. Similarly for planets in orbit around the stars.

So what we are asking is this: if the moving electric current drags the ionised part of the Sun along with it at the observed galactic rotation rates, will the non-ionised parts of the Sun and the solar system be dragged along gravitationally?

Taking our Sun as an example, using standard numbers and basic equations, and assuming that accepted notions of mass and distance are correct, we find the following:

The mass of the solar system is roughly the same as the mass of the sun, so we'll approximate the whole thing as a point of mass (m) 2e30 kg.

The distance to the centre of the galaxy (r) is 2.5e20 m.

The rotational velocity of the solar system around the core (w) is 8e-16 rad/s.

The centripetal force (F = m.r.w^2) keeping the Sun in orbit is therefore 3.2e20 N.

Now, let us assume that the Sun is homogenous (we can argue about that later). The average density is 1.4e3kg/m^3 and the volume is 1.4e27 m^3.

This gives an average centripetal force of 2.3e-7 N per m^3, assuming 100% ionisation.

For a 1 m^3 region of average density at the surface of the Sun, this centripetal force would equate to an acceleration (F = ma) of 2.3e-7 / 1.4e3 = 1.6e-10 m/s^2. The surface gravity is 274 m/s^2, so the neutral particles should remain gravitationally bound to the accelerating ions. (While the calculation assumed 100% ionisation, the margin is so high here that we should be able to have very little ionisation to ensure an electromagnetically dominated rotation around the galaxy.)

Thus it would seem that the self-gravity of the Sun should be sufficient to hold it together in the presence of an externally applied centripetal force.

Next let us consider the orbits of the planets and, assuming a worst-case of being uncharged and only gravitationally bound to the Sun, is gravity sufficient to keep the planets in orbit when in opposition/conjunction with the galactic core?

The centripetal acceleration (a = r.w^2) towards the galactic core is 1.6e-10 m/s^2. (This is the same number we arrived at above via calculation of the forces, which is a handy consistency check.)

Taking Pluto as the most problematic planet, its centripetal acceleration towards the Sun is 3.8e-6 m/s^2 - more than dominant. Thus the planets would remain gravitationally bound to the Sun and follow it around the galaxy.

The biggest (worst) assumption here is the averaging of the density and the equal distribution of the centripetal and self-gravitating forces. It's not likely to be so simple. Before we can depart from the given assumption, we need to decide qualitatively what the interior structure of the Sun may be and then look to see if it would still hold together, but there would appear to be many orders of magnitude of slack to take up before things fall apart. The tenuous atmosphere of the Sun, being very ionised, is clearly confined to the Sun by local fields (as observed, not just theory), so it is only the internal bulk that we need to worry about.

There are still open questions about the characteristics of the currents, fields, ionisation, and solar structure. What do these need to be to exert a 3.2e20 N force on the Sun? In the scheme of things, that force would appear to be very small. What are the arguments against it being unachievable?

If there are any mistakes in the maths or reasoning, feel free to point them out.

[jjohnson]

Nereid writes,

None of this is actually modelled, is it? I mean, per either of the 1986 papers, or the book.

In Chapter 3 of Physics of the Plasma Universe, discussing cosmic effects of the Biot-Savart law, Peratt devotes some time to discussing the Milky Way and his numeric (PIC) simulations of spiral and elliptical galaxies.

Pertinent to this discussion is section 3.11.4 Rotational Velocities of Spiral Galaxies (p. 128), Example 3.3, Rotational velocity of a simulated spiral galaxy. Peratt applies the mass correction factor (ref his 8.6.3) and the electric field correction factor (referenced as footnote 2) to come up with a rotational velocity of 226 km/s. This (simulated) curve is plotted against 5 other (real; observed) spiral galaxy rotation curves in his Figure 3.28 (6 plot boxes altogether) with good agreement. Peratt notes,

Concomitant with the lengthening of the arms is a thinning of the arms as shown in Figure 3.19. As discussed in Section 3.10.5, a diocotron instability is produced. This instability shows up in both the cross-sectional views of the spiral arms and the velocity profile, where a distinct vortex "saw-tooth" pattern is measured. Good examples of this instability are found in the Sc-type galaxies M101, NGC253, and NGC2998 [Arp 1986]. Figure 3.29, NGC3646, is an example of a very large diocotron instability, similar to that observed in auroras, in the spiral arms.

It is interesting (to me, anyway) that his simulation not only produced a reasonable galactic rotation velocity, it is similar in form to that of other measured galaxies, and also generates diocotron instabilities in the arms, a peculiarly unique plasma instability not modeled by gravity-only models to my knowledge (which as we all know is pretty limited) but which does show up in photographs in some types of spiral galaxies. Remember, this was done nearly 2 decades ago.
Jim

[Nereid]

Thanks very much Jim!

A couple of quick things to note:

* the bottom right-hand side curve in Figure 3.28, the simulation result, does not show feature 1) that is summarised in the intro to 3.11.4:

Figure 3.28 shows six radial velocity versus radius curves typical of spiral galaxies. There data show: 1) a nearly linear solid-body rotation for the galaxy center (the first few arcminutes from center),

* The very first few words of that intro are: "Rotational velocities of spiral galaxies are obtained by measuring the doppler shift of the Halpha line emitted by neutral hydrogen in the spiral arms." That is certainly one method, but is not the only method, even in the 1980s.

* the end of the intro is: "(beyond the first few arcminutes of, equivalentlly, the first few kiloparsecs)." This points to something not directly relevant to this thread (or is it?); namely, Peratt accepts, in all his galaxy formation and evolution work (or at least the two 1986 papers and the book), that the Hubble redshift-distance relationship is valid. Putting it bluntly, and turning up the contrast, any Arpian 'intrinsic redshift' in Peratt's work - including that on quasars - is insignificant.

(OK, that was three points).

[mharratsc]

Ms. Nereid said:

This points to something not directly relevant to this thread (or is it?); namely, Peratt accepts, in all his galaxy formation and evolution work (or at least the two 1986 papers and the book), that the Hubble redshift-distance relationship is valid. Putting it bluntly, and turning up the contrast, any Arpian 'intrinsic redshift' in Peratt's work - including that on quasars - is insignificant.

Using redshifted light to check a rotational velocity isn't quite the same as the argument being made by Mr. Arp, in my thinking.

[Siggy_G]

Using redshifted light to check a rotational velocity isn't quite the same as the argument being made by Mr. Arp, in my thinking.

Very true. Thornhill isn't refuting either, that a portion or some cases of redshift can be due to Doppler effect. The relative redshifts within a galaxy disc could properly account for its rotation.

The referenced argument is concerning whether the overall redshift in a galaxy is due to recession speed (and hence universal expansion) or a result of the age and state of the galaxy's (or quasar's) matter. The standard model assumes the forementioned, whilst EU theory supports the latter (i.e. Arp's work).