Plasma Cosmology - Woo or not

[robinson]

And just to be clear, on the average, large objects in our Universe are highly Electromagnetic, not neutral. This includes clouds of hydrogen (plasma) as well.

 

[Dancing David]

The wheels on the bus go round and round, round and round, the wheels on the bus go round and round...

Wouldn't the Debye length limit the scaling of EM forces as they get to galaxy and larger sizes?

 

[sol invictus]

After looking at images of objects shooting energetic particles and electrons 20,00 light years through space, or even a hundred million light years, I find the "gravity is stronger" belief system to be a bit ludicrous.

It's not a "belief system". It's the laws of physics.

Large objects, like stars, black holes, galaxies and stuff like that, are anything but neutral when it comes to EM. I think the problem is some people only consider EM to be electricity, rather than a term that refers to all energies in the EM spectrum, including of course, magnetism.

Sigh.

I'll never understand the impulse that leads people to post authoritative-sounding statements on topics they are obviously totally ignorant of. Large objects are almost exactly neutral. For example, the earth does not have a significant net electric charge. Neither does the sun. Neither do any of the other planets, the milky way, or any other known large object.

The reason is trivial. In the universe there are very close to as many electrons as protons. Suppose you were to pick randomly from a collection of positive and negative particles to make a chunk of stuff. If you picked N particle, the net charge of the object would be of order the square root of N. But the mass (which is gravitational "charge") would simply be N, and so for large enough N, gravity is much stronger than EM.

Of course objects don't form randomly like that - if something did end up with a significant charge, it would rapidly neutralize itself by ejecting particles with like charge and accreting particle with opposite charge.

Our nearby friend Jupiter is a good example. Considered "neutral" by some, it has the most powerful magnetic field of any object we can directly measure. The magnetic field is far more influential at a distance than it's gravity, which is pretty impressive as well.

Magnetic fields can and do exist for objects with zero net charge. You didn't know that, since you have no idea what you are talking about.

Comparing gravity and EM is apples and oranges. The only things they have in common, are that they both are ever present, infinite in effect, and neither one can change the other!

This statement is too meaningless for me to be able to comment.

And just to be clear, on the average, large objects in our Universe are highly Electromagnetic, not neutral. This includes clouds of hydrogen (plasma) as well.

Again, you exhibit your ignorance of the meanings of the terms you use. It's a really bad idea to try to say things using words you don't know the meaning of.

 

[robinson]

Magnetic fields can and do exist for objects with zero net charge. You didn't know that, since you have no idea what you are talking about.

Again, when discussing EM, charge is one part of the subject. Photons, magnetism, both are part of EM. While a large object may be considered electrically neutral, that does not mean it's EM does not influence other objects at tremendous distances.

An energetic jet a hundred million light years long certainly is more influential than the objects gravity at that distance.

Especially if you happen to be near the jet.

Most large objects (not small planets) are energetic in the EM realm, and influence other objects at great distances. The gravity from a super Nova is negligible compared to the charged particles and EM radiation emitted. Especially at great distances.

We feel practically nothing gravity wise from a nearby Nova. But the the EM could kill us.

Again, don't confuse small objects with their mostly neutral charge, with large objects. Moving plasmas may be neutral, from an electric charge point of view, but their EM effects are vastly more powerful than their gravity.

And a hot plasma cloud 10 thousand light years across is certainly a large object.

 

[sol invictus]

Again, when discussing EM, charge is one part of the subject. Photons, magnetism, both are part of EM. While a large object may be considered electrically neutral, that does not mean it's EM does not influence other objects at tremendous distances.

Good - so you now agree that large objects are neutral. That means they have no electric field, so let's move on and address the issue of magnetic fields. We could ask, for example, whether the magnetic field of a star can affect the motion of another star, or whether the mag. field. of a galaxy can affect the motion of another galaxy in the same cluster. The answer is no - those forces are extremely weak. However the gravitational attraction between the two can be very significant (in fact it determines the motion).

We feel practically nothing gravity wise from a nearby Nova. But the the EM could kill us.

It's not just EM that's involved there, but yes, that's correct. To take a more prosaic example, it's much easier to detect the light from a distant star than it is to detect its gravitational field. Nevertheless, the force exerted by that starlight on a distant object is much smaller than the force exerted by the gravity of the star on the object. So if we are interested in the motions of these objects, gravity is essentially the only thing which matters.

Anyway the whole idea that EM effects are somehow neglected in astrophysics is absurd. Astros study plasmas, stars, magnetic fields, the CMB, star light, radio waves, absorption lines, etc. etc. etc.

 

[Tubbythin]

Robinson, calculate the gravitational force on Earth from the Sun. Calculate the force of radiation pressure on Earth from the Sun. Divide the former by the latter. Conclude.

 

[BeAChooser]

Dark matter (actually observed)

Has it?

and dark energy (the effects of which have been observed) have nothing to do with scaling.

http://home.fnal.gov/~rocky/DETF/Adelberger.pdf "Project: Laboratory Tests of Gravity at the Dark Energy Length Scale"

http://arxiv.org/abs/0710.3885 "The observed cosmic acceleration today could be due to an unknown energy component (dark energy), or a modification to general relativity (modified gravity). If dark energy models and modified gravity models are required to predict the same cosmic expansion history H(z), they will predict different growth rate for cosmic large scale structure, f_g(z)=d\ln \delta/d\ln a (\delta=(\rho_m-\bar{\rho_m})/\bar{\rho_m}), a is the cosmic scale factor)."

http://meetings.aps.org/Meeting/APR08/Event/83802 "The acceleration of the universe can be explained either through dark energy or through the modification of gravity on large scales. In this paper we investigate modified gravity models and compare their observable predictions with dark energy models. Modifications of general relativity are expected to be scale-independent on super-horizon scales and scale-dependent on sub-horizon scales. For scale-independent modifications, utilizing the conservation of the curvature scalar and a parameterized post-Newtonian formulation of cosmological perturbations, we derive results for large scale structure growth, weak gravitational lensing, and cosmic microwave background anisotropy. For scale-dependent modifications, inspired by recent $f(R)$ theories we introduce a parameterization for the gravitational coupling $G$ and the post-Newtonian parameter $\gamma$. These parameterizations provide a convenient formalism for testing general relativity. However, we find that if dark energy is generalized to include both entropy and shear stress perturbations, and the dynamics of dark energy is unknown a priori, then modified gravity cannot in general be distinguished from dark energy using cosmological linear perturbations."

And yes gravity can be scaled - see Newtons law of gravity and GR.

And what is it about the laws governing plasmas and their behavior that makes you think they won't scale? Keep in mind that it's already been demonstrated that they scale over an immense range. Why not the rest of the way?

 

[robinson]

Good - so you now agree that large objects are neutral.

I don't know if you are dense or deliberately obtuse sometimes. Rather than respond to a multitude of points, all in support of the contentious subject, you say something like that.

Again, when discussing EM, charge is one part of the subject. Photons, magnetism, both are part of EM. While a large object may be considered electrically neutral, that does not mean it's EM does not influence other objects at tremendous distances.

An energetic jet a hundred million light years long certainly is more influential than the objects gravity at that distance.

Especially if you happen to be near the jet.

Most large objects (not small planets) are energetic in the EM realm, and influence other objects at great distances. The gravity from a super Nova is negligible compared to the charged particles and EM radiation emitted. Especially at great distances.
Again, at great distances, that dwarf any gravitational effect. Which is the opposite of the claim that gravity is all that matters at great distances. EM effects can actually destroy large structures/objects, at distances that make gravity a minor note.

Again, don't confuse small objects with their mostly neutral charge, with large objects. Moving plasmas may be neutral, from an electric charge point of view, but their EM effects are vastly more powerful than their gravity.

And a hot plasma cloud 10 thousand light years across is certainly a large object.

It's not just EM that's involved there, but yes, that's correct. To take a more prosaic example, it's much easier to detect the light from a distant star than it is to detect its gravitational field. Nevertheless, the force exerted by that starlight on a distant object is much smaller than the force exerted by the gravity of the star on the object. So if we are interested in the motions of these objects, gravity is essentially the only thing which matters.

While you want to focus on motion, even there, when looking at very large objects/structures. EM is far more important. It is essential to the very formation of objects. Gravity isn't nearly as important as EM in the formation of large objects.

Robinson, calculate the gravitational force on Earth from the Sun. Calculate the force of radiation pressure on Earth from the Sun....

That sort of simplistic thinking avoids the practical reality. But let us use the earth, a small neutral body, to do some calculations and thought experiments, in regards to motion and gravity. Everybody will gain something. It will even be on topic.

 

[robinson]

This is worth an entire topic. It is that good.

Gravity or EM?

 

[Reality Check]

Has it?

Yes it has

...snipped not relevant dark enery links...

And what is it about the laws governing plasmas and their behavior that makes you think they won't scale? Keep in mind that it's already been demonstrated that they scale over an immense range. Why not the rest of the way?

We know that gravity scales to all lengths because there is nothing that can shield it.
Plasma scaling though is much more complex. There is no evidence that there is scaling beyond intergalactic scales. pc proponents are merely indulging in wishful thinking.

P.S. Do you have any more theories to add to the pc collection?

 

[sol invictus]

I don't know if you are dense or deliberately obtuse sometimes. Rather than respond to a multitude of points, all in support of the contentious subject, you say something like that.

Again, when discussing EM, charge is one part of the subject. Photons, magnetism, both are part of EM.

Did you read past the first sentence of my post? Here are the first two:

Good - so you now agree that large objects are neutral. That means they have no electric field, so let's move on and address the issue of magnetic fields.

While a large object may be considered electrically neutral, that does not mean it's EM does not influence other objects at tremendous distances.

No one is saying EM effects cannot influence things far away. What we are saying is that galactic rotation curves for stars have nothing to do with EM.

Which is the opposite of the claim that gravity is all that matters at great distances.

You are attacking a strawman. No one has claimed that EM is never important at large scales under any circumstances. The issue is whether large-scale motions of matter, such as the orbits of planets, stars, and galaxies, are significantly affected by EM forces. The answer is almost always no.

Again, don't confuse small objects with their mostly neutral charge, with large objects. Moving plasmas may be neutral, from an electric charge point of view, but their EM effects are vastly more powerful than their gravity.

Gibberish. I have no idea what that is supposed to mean. Plasmas have very close to zero net charge.

That sort of simplistic thinking avoids the practical reality. But let us use the earth, a small neutral body, to do some calculations and thought experiments, in regards to motion and gravity. Everybody will gain something. It will even be on topic.

We already did, long ago, in another thread on the same topic. However calculations are totally unnecessary, because the answer is obvious to anyone with even a shred of physical intuition.

Here's an order of mag estimate: since both forces fall off as one over distance squared, we just need to compare the coefficients. Those are the charge of the sun times the charge of the earth in the case of electric force, and the mass of the sun times the mass of the earth for gravity. Multiplying by the appropriate constants in my head, I get 10^43 for gravity, and 10^22 for the electric force (using an extremely generous estimate for the charges, namely that they are the square root of the number of protons times the charge of the proton). So gravity is a billion trillion times stronger.

 

[Zeuzzz]

Sigh.

I'll never understand the impulse that leads people to post authoritative-sounding statements on topics they are obviously totally ignorant of. Large objects are almost exactly neutral. For example, the earth does not have a significant net electric charge. Neither does the sun. Neither do any of the other planets, the milky way, or any other known large object.

Utter nonsense. I suppose that the numerous pulsars, and other similar type stars, that are charged up to quadrillions of Volts do not count as 'significant net charge' (see this for example; Chandra Examines Quadrillion-Volt Pulsar. Before we get bogged down in this argument again, lets just say that currently it is not fully known what the charge on large objects in space is, apart from a few theoretical estimates. Some of which have been discussed at great length here, but none of them say that objects are completely neutral, and most arrive at different values depending on their methodology.

Magnetic fields can and do exist for objects with zero net charge. You didn't know that, since you have no idea what you are talking about.

for zero net charge, strictly speaking, yes they can, but without the motion of charge you can not generate magnetic fields, they are inextricably linked via Maxwells electromagnetism.

After looking at images of objects shooting energetic particles and electrons 20,00 light years through space, or even a hundred million light years, I find the "gravity is stronger" belief system to be a bit ludicrous.

It's not a "belief system". It's the laws of physics.

But the way that you represent it certainly makes it seem more like a belief system than a fundamental law. Maybe the nature of gravity is not so fundamental, and you should consider some of the assumptions in the theory. Maybe your faith in how gravity functions in the universe is misplaced. Ever consider that?

In his excellent book on the worrying situation of theoretical physics, Lee Smolin gives an example of the mechanism that leads to such a narrowing of our view: “The possibility - that we are wrong about Newton’s laws, and by extension general relativity - is too scary to contemplate.” (page 15). Indeed.

There are major problems with the applicability of Newtons law of gravitation. This law is the sole reason why cosmology/astronomy is filled with so many unresolved problems, most notably dark matter and dark energy. Rarely are dark matter and dark energy seen as problems with gravity, but that is exactly what they are, entities invoked to try to explain the plethora of objects in space that do not follow the gravitational model of an exclusively attractive field.

There is no definitive law for gravity at all scales. Newtonian gravity is accurately measured and proven with the bounds of the solar system. However, Newtonian gravity remains untested in other areas. All we have is the formula. This formula has been used to determine the mass of the Earth. This is based on the concept that for each mass of M inside the Earth, it exerts an equal attractive force of F. We do not know the valid range for Newtonian gravity. It is assumed, and assumed is the correct word here, that each mass of M exerts the same force of F regardless of where in the universe it may be placed. It is also assumed that each mass of M exerts the same force F whether it lies on the surface of the Earth or whether it be deep inside the Earth. When using the Cavendish balance to determine the mass of the Earth, it is assumed that each particle exerts a fixed force upon all others. This assumption rules out the very real possibility that particles near the surface of a planet might exert a force greater/less than those deep down.

The key to all of our gravity is the mass of the Earth. If the mass of the Earth is wrong, then so are our estimates for those of other bodies. If the mass of the Earth has been overstated, then it follows that the masses of other bodies have also been overstated.


There is however one method that would be able to prove the Newtons law of gravity on a geophysical scale very directly. This would be to take measurements of the gradient of g as you descend into the Earth. Strangely, not much research has been done into measuring this accurately. And the few experiments that have measured it seem to give very different values than Newtons law would predict.

Testing the inverse-square law of gravity on a 465-m tower

Tower gravity experiment - Evidence for non-Newtonian gravity

The authors tested Newton's inverse-square law of gravitation by comparing gravity measured on a 600-m tower with gravity calculated from ground measurements. A significant departure from the law was detected, approaching (-500±35)×10^-8m s^-2 at the top of the tower and suggestive of a rapidly attenuating non-Newtonian attractive force. These results are marginally consistent with a one-term Yukawa-type attractive force, but they are fully consistent with two Yukawa-type forces, attractive and repulsive, and then also with Airy and Cavendish experiments.

The data from this was questioned by some, but further evidence for a discrepancy from Newton’s law was found for a deep mine hole.

Gravity in mines - An investigation of Newton's law - hysical Review D (Particles and Fields), Volume 33, Issue 12

Recent history of tower and mine searches for non-Newtonian gravity

The evidence that the value of the Newtonian gravitational constant G inferred from measurements of gravity g in mines and boreholes is of order 1% higher than the laboratory value is hardened with new and improved data from two mines in northwest Queensland. [….]

And these results have been backed up by further tests in Greenland on the ice sheets.

Test of Newton's inverse-square law in the Greenland ice cap

An Airy-type geophysical experiment was performed in a 2-km-deep hole in the Greenland ice cap at depths of between 213 and 1673 m in order to explore possible violations of Newton's inverse-square law. The results revealed an anomalous gravity gradient. [….]

So from an experimental viewpoint, Newtons law runs into various problems even right here on Earth. Who knows what problems it faces when extrapolated to the large scale constituents of the universe.


Since gravity was related by Einstein to the geometry of space-time (whatever the hell that physically is) gravity has received support from various tests, such as the perihelion of mercury, and others. However, the following quote from a very popular book on astronomy, is quite remarkable:

Galactic dynamics (page 635)

"It is worth remembering that all of the discussion so far has been based on the premise that Newtonian gravity and general relativity are correct on large scales. In fact, there is little or no direct evidence that conventional theories of gravity are correct on scales much larger than a parsec or so. Newtonian gravity works extremely well on scales of ∼ 10¹⁴cm (the solar system).
(...) It is principally the elegance of general relativity and its success in solar system tests that lead us to the bold extrapolation that the gravitational interaction has the form GM/r² on the scales 10²¹ − 10²⁶cm..."

[....]

The above cited 'bold extrapolation' of gravity seems to have encountered problems even in the solar system now, with the pioneer and voyager anomalies, so it seems very naive to presume that gravity functions how we currently model it when applied to much larger scales.

Many tests show that gravity obeys an inverse square law in terms of distance, but little work has been done on observations that test the dependence on the field mass, M. Since mass estimates of the whole universe depend on it, determining the absolute value of G is kinda important. The thing is that they all tend to give different values for G, and whereas other (fundamental) constants in nature achieve an accuracy of over 12 decimal places the value of the gravitational constant lags behind with far greater uncertainty, with only about 3-4 decimal places remaining undisputed by various methods. This indicates that we still have a lot to learn about the true nature of gravity.

A lot of work has been done on determining the value of G. What seems lacking however are test which test the spatial and temporal dependence of G, which can also be used to test Newtons law as well. At the atomic level, although you can work out the ratio of electric and gravitational forces at 2.27x10³⁹ (respectively), this has never been measured as particles this size are too light to be used as field masses. Gravity is amazingly illusive at this small scale, and remains so right up to much larger scales. At the standard laboratory scale the torsion balance is the usual method, done usually over a distance of 10 – 30 cm, which is the method used by originally by cavendish, which has changed very little to this day. One further method is by using a superconducting gravimeter and a moving mass (see http://www.iop.org/EJ/abstract/0957-0233/10/6/311).


And that’s about it from methods of determining G directly. We only have direct confirmation of this law over a very small scale range, from laboratory to geological size, it is presumed from this that it applies exactly to all other scales. Other larger scale methods like satellite based experiment’s to find the value of G, such as LLG, are in fact finding the product M_EG, using the mass of the Earth, under the presumption it is correct, and other larger scale estimates use generally use the mass of the sun (inferred from the mass of the Earth) to determine G.



Another interesting way to test gravity would be check the dependency of Newtons law on the amount of field mass in question. Which is an idea lacking much experimental verification too. When M = m (in F=GMm/r²) the law becomes symmetric, but a deviation for large masses would not violate the equivalence principle, at least within its experimental constraints which apply mostly to test masses. It is often claimed that any physical theory has to be linear in the weak-field-limit, but this cannot be definitively proven, mainly due to the amazingly weak nature of gravity making tests for this very hard. We just perform an extrapolation of our mathematical methods, which should be tested. There are plenty of ways to test the r² term in Newtons law, but testing the exponent 1 on M is much more difficult to prove.

Torsion balance experiments typically use masses in the range 5 – 20 Kg, and this is the mass at which we base our most accurate measurements of G. And this mass range goes up to about 10⁷ Kg with lake experiments to measure gravity (see: Determination of the gravitational constant with a lake experiment.), which achieved results close to laboratory values, but not to such a high degree of accuracy. Generally, the more mass is used the less reliable the value becomes. And when you get to the solar system scale satellite data of planetary orbits can not be used to find the field mass dependence of Newtons law (ie, the exponent of M not equal to 1 in F=GMm/r²) as the same data is used to measure the mass. You can use Keplers law to test the validity of the inverse square relationship, but this can not reveal an exponent of M different from 1. This problem stems from not being able to find independent mass estimates of these larger scale objects (apart from some very crude methods with a very high amount of uncertainty), and so from the mass range of the moon \earth (10²³ kg) all the way up to sun, no accurate test for this exists. When dealing with the galactic scale (from 10³⁹ to 10⁴⁴) you run into the same problem of not having independent mass estimates. And this applies to all scales above the solar system. Solar mass to light ratio measurements for galaxies do not fit the dynamically determined mass, and so dark matter is invented to explain this failure of Newton’s law. And right up on the cosmological scale Newtons law fails, and so dark energy is invoked to explain the anomalies. So over time Newtons law has been patched up with numerous ad hoc solutions, but maybe instead of just assuming these entities exist and can explain away everything we should just consider that the law of gravity is plain wrong when applied to large scales. This is where theories like MOND and others come in. And while MOND presents more problems than it solves (in my opinion), it has been very useful in pointing out another problem with Newtons law, that it is poorly tested for accelerations below 10⁻¹⁰ms⁻².



I think that it is highly likely that the hierarchy of structures in the universe, the lab, earth, solar system, galactic, cosmic does not stop at the laws that we use in the solar system but requires a corresponding hierarchy of theories. Inventing new entities and new free parameters to simulations will not be sufficient; this type of approach seems to me to be a modern day version of the epicycles of Ptolemy. Extrapolating theories beyond their true testable scope should be avoided, unless we want to walk down the path of ever more complex theories piled up ontop of each other in an attempt to try to hold on to the basic law underlying them all, this type of approach merits a warning from history.



The amount of research that is done in cosmology based on this unverified extrapolation of gravity over some 14 orders of magnitude is quite a remarkable spectacle.

There are considerable gaps in our knowledge about how gravity functions at large scales. Take a look at this graph for example;

Generally objects fall into three groups at different scales. The group on the left are the only area where direct absolute measurements of G are possible, from tiny scales up to geological scales. Everything else on this table, from our satellites up to super-massive black holes are extrapolations of Newtons law that remain to be tested, as even the middle group are testing Keplers law rather than Newtons. For the group on the right, none of them offer any sort of undisputable evidence for Newtons law, without having to invoke quantities such as dark matter or energy. To put it simply, tests of the field mass dependence are entirely determined by only 1-2 independent types of experiments on the small scale. The extrapolation to the other larger objects is assumed.



The interesting thing about Maxwells electromagnetism is that it is not like gravity, it is scale invariant. Gravity has no effect on that atomic scale. But it does on the solar scale. And it is assumed to be the only force that can effect even larger scales. But the sheer amount of large scale objects that do not obey Newtons law by their shape and structure, certainly imply that other forces are at work on the large scale. And now we know that plasma is so pervasive in the universe, something not known when most gravitational models were invented back when they thought that space was a void of empty space, EM forces in plasma are the obvious candidate to explain these objects. As I said before;

For example, take the electric field E(x,a), which by Maxwell are represented by [latex]\nabla^{2}E=\frac{1}{c^2}\frac{\delta^{2}E}{\delta{a^2}}[/latex] [and also the equivalent form magnetism applies, using B(x,a) ]. For the transformation [latex]x \rightarrow \lambda{x}[/latex] and also [latex]\lambda{x} \rightarrow \lambda{x}[/latex], the relationship holds, giving scale invariant field equations. Maxwell’s Electromagnetism is scale invariant.

I would highly recommend reading about large scale plasma/EM forces Sol, due to this fact. You continually ignore the fact that we are not talking about electro/magnetostatics in neutral gasses, we are referring to these forces in plasmas, where the charges are separated into ions, and EM forces can have long distance interactions. Yes, you can show (and so can I, or anyone else for that matter) that EM forces in a neutral medium can not account for large scale motion of objects, but that’s not applicable to the universe, as the visible universe is 99% plasma, not neutral gas. The properties of plasma are very complex, and are still being investigated to this day, but it is now generally becoming accepted that in plasma EM forces can have long range interactions comparable to gravity.

http://www.ctr4process.org/programs/LSI/2006-Cosmology/EastmanT - Cosmic Agnosticism.pdf

By definition, plasmas are an interactive mix of charged particles, neutrals, and fields that exhibits collective effects. In plasmas, charged particles are subject to long-range, collective Coulomb interactions with many distant encounters. Although the electrostatic force drops with distance (~1/r²), the combined effect of all charged particles might not decay because the interacting volume increases as r³. Magnetic field effects are often global with their connections
reaching to galactic scales and beyond. [….]

How else can you explain galactic wide magnetic fields?

And I would start with these two publications for detailed descriptions of large scale EM interactions in space plasma and how they function;

Advances in Numerical Modeling of Astrophysical and Space Plasma, A. L. Peratt, APSS 242, 1997 (3.3MB)

Advances in Numerical Modeling of Astrophysical and Space Plasma, Part II Astrophysical Force Laws on the Large Scale. A .L. Peratt, APSS 256, 1998 [Adobe annotated edition]

 

[Zeuzzz]

We know that gravity scales to all lengths because there is nothing that can shield it.

And how does the fact that we know that nothing can shied gravity prove that "gravity scales"? To what extent, and over what scales?

Plasma scaling though is much more complex. There is no evidence that there is scaling beyond intergalactic scales.

Where on earth did you get this idea? Care to explain why?

And that wiki article is interesting considering their two main references are to the two main plasma cosmology proponents, Alfven and Peratt. And peratts publication, http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1996Ap&SS.242...93P they cite, is 1996, not 1966. And the other two references seem ancient, from 1940's and 1930's, a lot of progress has been made on plasma scaling by Peratt and colleagues since then. I may even add some of his newer material to this page, especially some of his work about the scaling properties of birkeland currents, which do not change their structure over many orderds of magnitude at all (whereas general plasma obeys slightly more specific rules). For plasma scaling relations, Peratts material is considered the worlds most extensive and respected.

http://en.wikipedia.org/wiki/Plasma_scaling#See_also

# After Peratt, A. L., "Advances in Numerical Modeling of Astrophysical and Space Plasmas" (1966) Astrophysics and Space Science, v. 242, Issue 1/2, p. 93-163.

# ^ Cobine, J. D ., 1941: Gaseous Conductors, McGraw-Hill . New York

# ^ von Engel, A., and Steenbeck, M., 1934: ElektrischeGasentladungen, Springer-Verlag, Berlin. See also von Engel, 1955: Ionized Gases, Clarendon Press, Oxford.

# ^ H. Alfvén and C.-G. Falthammar, Cosmic electrodynamics (2nd Edition, Clarendon press, Oxford, 1963) See 4.2.2. Similarity Transformations

pc proponents are merely indulging in wishful thinking.

And I suppose a universe filled with 96% matter, which we have never detected and the properties of which we dont have a clue about what-so-ever, invoked solely to patch up the holes in the original gravitationally driven models, is not wishful thinking? I think we can safely say that PC models rely on far less wishful thinking than most mainstream theories.

P.S. Do you have any more theories to add to the pc collection?

Yes, dozens. But we've hardly been able to agree on any of the ones so far, so there no point introducing any of the other PC models until we can reach some sort of consensus on the ones discussed so far.

 

[robinson]

No one is saying EM effects cannot influence things far away. What we are saying is that galactic rotation curves for stars have nothing to do with EM.

One reason this discovery is so significant is because hydrogen radiation is not impeded by interstellar dust. Optical observations of the Galaxy are limited due to the interstellar dust, which does not allow the penetration of light waves. However, this problem does not arise when making radio measurements of the HI region. Radiation from this region can be detected anywhere in our Galaxy.

Measurements of the HI region of the Galaxy can be used in various calculations. For example, observations of the 21-cm line can be used to create the rotation curve for our Milky Way Galaxy. If hydrogen atoms are distributed uniformly throughout the Galaxy, a 21-cm line will be detected from all points along the line of sight of our telescope. The only difference will be that all of these spectra will have different Doppler shifts. Once the rotation curve for the Galaxy is known, it can be used to find the distances to various objects. By knowing the Doppler shift of a body, its angular velocity can be calculated. Combining this angular velocity and the plot of the rotation curve, the distance to a certain object can be inferred. Using measurements of the HI region, the mass of the Galaxy can also be determined.

http://www.haystack.mit.edu/edu/undergrad/srt/SRT Projects/rotation.html

Hmm, I see a problem with this ...

 

[sol invictus]

Utter nonsense. I suppose that the numerous pulsars, and other similar type stars, that are charged up to quadrillions of Volts do not count as 'significant net charge' (see this for example; Chandra Examines Quadrillion-Volt Pulsar. Before we get bogged down in this argument again, lets just say that currently it is not fully known what the charge on large objects in space is, apart from a few theoretical estimates. Some of which have been discussed at great length here, but none of them say that objects are completely neutral, and most arrive at different values depending on their methodology.

That is a bald-faced lie. We went through this, you agreed with the conclusion at the time, and now you're lying about it again.

We went through the math in excrutiating and totally unnecessary detail - both for forces on stars and for the Pioneer anomaly - several months back. A star cannot have a charge anywhere near what it would need to be for EM forces on it to significantly affect its motion. That follows immediately from basic consistency - the charge would have to be so large that the star would instantly explode under its own electrostatic repulsion.

You obviously have no interest in truth or reality, only in some bizarre obsession with "plasma cosmology". You're very much like a 9/11 conspiracy theorist - immune to logic, truth, the laws of physics, and capable of very rapidly forgetting your lessons.

for zero net charge, strictly speaking, yes they can, but without the motion of charge you can not generate magnetic fields, they are inextricably linked via Maxwells electromagnetism.

Oh really? Care to tell me where the currents in a permanent magnet are?

The rest of your post is a mish-mash of nonsense and some old discredited results. People are constantly searching for violations of Newton's law. Anyone that discovers it will become extremely famous and win the highest award in physics - the Nobel prize - in short order. And yet according to you, there is some vast conspiracy to suppress these results. More 9/11 style trash.

 

[sol invictus]

http://www.haystack.mit.edu/edu/undergrad/srt/SRT Projects/rotation.html

Hmm, I see a problem with this ...

No you don't - you just think you do. We can measure rotation curves for both stars and dust in many galaxies, and they agree quite nicely.

 

[robinson]

That would be the problem.

 

[Zeuzzz]

We went through the math in excrutiating and totally unnecessary detail - both for forces on stars and for the Pioneer anomaly - several months back. A star cannot have a charge anywhere near what it would need to be for EM forces on it to significantly affect its motion. That follows immediately from basic consistency - the charge would have to be so large that the star would instantly explode under its own electrostatic repulsion.

.


Not if electrostatic repulsion was the thing stopping the star from collapsing in the first place, instead of hydrostatic equilibrium from the energy being produced at the core, ie, the nuclear model. It often helps to know the model you are arguing against before critisising it.

You obviously have no interest in truth or reality, only in some bizarre obsession with "plasma cosmology". You're very much like a 9/11 conspiracy theorist - immune to logic, truth, the laws of physics, and capable of very rapidly forgetting your lessons.

Are you still trying to make it easier for you to come to terms with by denying that "plasma cosmology" exists? why use quotation brackets?

And please, if you think that your giving me "lessons", quite to the contrary, the only thing your giving me lessons in is how hard it is to get someone who has spent his life adhering to a certain scientific model to consider alternatives.

Oh really? Care to tell me where the currents in a permanent magnet are?

Due to the magnetic moments of the atoms, which is related to the motion of charge.

The rest of your post is a mish-mash of nonsense and some old discredited results. People are constantly searching for violations of Newton's law. Anyone that discovers it will become extremely famous and win the highest award in physics - the Nobel prize - in short order.

Ok. Maybe they were just measuring anomalies. I'm prepared to accept that. I would like to see what the measuring anomalies are, but never mind.

Care to address anything else in my post? or are you going to do the usual reply to one tiny apsect, and ignore/presume that everything else I posted is wrong? This aspect is one tiny part of the material I just posted. You silly person you.

Like whats wrong with the publications about large distance EM force laws in plasma in space? or the statement about long scale EM interactions? or any of the other stuff?

Whats wrong with this?

http://adsabs.harvard.edu/abs/1987gady.book.....B

"It is worth remembering that all of the discussion so far has been based on the premise that Newtonian gravity and general relativity are correct on large scales. In fact, there is little or no direct evidence that conventional theories of gravity are correct on scales much larger than a parsec or so. Newtonian gravity works extremely well on scales of ∼ 10¹⁴cm (the solar system).
(...) It is principally the elegance of general relativity and its success in solar system tests that lead us to the bold extrapolation that the gravitational interaction has the form GM/r2 on the scales 10²¹ − 10²⁶cm..."

are they wrong about this assumption?

 

[Tubbythin]

There are major problems with the applicability of Newtons law of gravitation. This law is the sole reason why cosmology/astronomy is filled with so many unresolved problems, most notably dark matter and dark energy. Rarely are dark matter and dark energy seen as problems with gravity, but that is exactly what they are, entities invoked to try to explain the plethora of objects in space that do not follow the gravitational model of an exclusively attractive field.

Erm. What do you think you have to invoke to explain a steady state Universe Zeuzzz?

It is assumed, and assumed is the correct word here, that each mass of M exerts the same force of F regardless of where in the universe it may be placed.

That's translational invariance of the laws of physics. If the laws of physics are not translationally invariant we might as well give up now. (Btw, you need two bodies for a force to be exerted.)

It is also assumed that each mass of M exerts the same force F whether it lies on the surface of the Earth or whether it be deep inside the Earth. When using the Cavendish balance to determine the mass of the Earth, it is assumed that each particle exerts a fixed force upon all others. This assumption rules out the very real possibility that particles near the surface of a planet might exert a force greater/less than those deep down.

This is utter rubbish. The particle's closer to us obviously exert a greater force compared to ones of the same mass further away. BUt for spherically symmetric objects we can consider them as a single point at the centre. Newton showed this and invented calculus in the process.

 

[Zeuzzz]

That's translational invariance of the laws of physics. If the laws of physics are not translationally invariant we might as well give up now. (Btw, you need two bodies for a force to be exerted.)

Really, you need two?

Yep, crap, lets just give up. Game over.

The particle's closer to us obviously exert a greater force compared to ones of the same mass further away.

Well, dir. 1/r²

BUt for spherically symmetric objects we can consider them as a single point at the centre. Newton showed this and invented calculus in the process.

This has nothing to do with anything. COM is all very well, and I'm not trying to undermine that. I suggest you read the rest of my post where I elaborate on my position, not just the first few sentences.