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#20 by meberbs on 02 May, 2019 16:39
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The cavity below is the version of "bell cavity" with only impulsive boundary conditions intrinsic curvature at the junctions, been zero ( boundary conditions intrinsic curvature) at walls.
You have been asked to clarify what in the world you are talking about previously, please respond to the questions you were previously asked:
Theorically, it will presents the same narrows modes pointed on previous quote.
https://forum.nasaspaceflight.com/index.php?topic=45824.msg1935741#msg1935741Thank you for the answers, explanations and references.
I am not convinced you know what the words you are using mean. Your statement here does not appear to have any relevance to anything. If you want anyone to be able to discuss what you are talking about sensibly, you have to provide more information:
What I've found is a 4D discrete cyclic group, and involves a totally spatial spherical surface of inversion.
How many elements are in the group?
Please list the elements of the group mathematically, including the mathematical relationship between these objects. -
#21 by meberbs on 02 May, 2019 18:04
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First of all, thanks for the detailed response.
Testable (and usually therefore numerical) predictions are fundamental to science. The model seems overall to provide a bunch of broad descriptions, so it is expected that most physicists would be extremely skeptical (this is not to say that the other poster was not being inappropriate in how they approached this issue.)-Are there any actual testable and falsifiable predictions made? (for example a calculation of how bright the radiation from the "black" part of the image would be and whether that would be distinguishable from the noise in this measurement.)
Not to my knowledge for now. If someday some radiation is indeed detected as being emitted in this place, although it shouldn't, one could argue it is due to some excited interstellar gas located not in the center of the object, but between the object and us. So more objects of this type should be studied, and obviously this is only the very beginning.
The point of these questions is that to make claims about magnetic pressure somehow allowing this object to exist, you would need to have some explanation for these things. It is not that uncharged objects can't have a magnetic field, but high magnetic fields in things like collapsed stars involve a plasma with high rotational velocity due to collapse to a small object and conservation of angular momentum. This is in contradiction to the low density gas that Petit is claiming exists instead of a black hole. And this is assuming that density is uniform, it is difficult to imagine a plausible density variation that does not involve a collapse into a black hole.Quote-What form of matter is the object supposedly made out of?
This is a low-density ball of plasma, ionized interstellar gas and dust, the same type of matter found in all galaxies. Not a particular type of exotic matter if this is the sense of your question.Quote-Where exactly does this supposed extremely large magnetic field come from, since the object as a whole is almost certainly neutral overall?
The fact is that scientists do not know exactly the origin of such magnetic field in (around) these object, they just acknowledge that there are magnetic fields there. ...
If the object was a coil exerting a force on itself, those equations would be correct, but it is supposedly a great big ball of gas, so the pressure felt at any point would be related to the field gradient, which would be much smaller.Quote-How does such a magnetic field produce the pressure needed to cancel the force of gravity, saying "big magnetic field" isn't enough. The object is less dense than air at sea level, by a factor of around 3 so it really doesn't make sense that such a large radius could be maintained by "magnetic pressure"
I do not have calculations for the gravitational force pulling such an object inward so can't really answer your question.
But as I said, magnetic pressure is equal to B²/2΅₀. Taking a magnetic field of 2Χ104 teslas such as in the example above, the outward pressure at the center of the object is equal to almost 4Χ1013 pascals, i.e. nearly 400 millions times the standard atmospheric pressure at sea level.I agree precise calculations should be done.
Let me know if they ever are, but this is the kind of thing that someone should do before making claims that black holes don't exist.So the Janus model could still work if black holes were definitely proven to exist, but it would be a bit less plausible and coherent.
I find it simply implausible that such a wide variety of black holes could exist (including neutron star and black hole mergers detected through gravitational waves) all of them somehow balanced by things like magnetic fields that somehow perfectly balance the enormous gravitational pulls.
I looked at the attachments you provided, but one has essentially no math of his own in it. The other one starts off with a contradiction, because it is complaining about infinite pressures occurring "before" collapse to a black hole, but it discusses this happening when the radius of the star is less than the Schwarzschild radius, which implies it already would be a black hole. Basic math errors like this should be explained before it is worth reviewing anything in more detail.
Since it is implausible that magnetic fields somehow perfectly cancel gravity in a wide variety of cases, and the explanation that high pressure causes matter to just get dumped into the other spacetime has multiple problems (where are all of the matching white holes in our side from the other side? This would lead to the conclusion that mass should generally just be dumped until a common cause (neutron degeneracy pressure) can support the star at the minimal radius) I therefore conclude that the model as currently formulated is not particularly plausible or coherent.
If better explanations and some actual falsifiable hypotheses are presented let me know, otherwise, this model does not seem worth following or investigating further. -
#22 by flux_capacitor on 02 May, 2019 19:09
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meberbs, thanks for having taking time to look at the papers, even quickly. On the qualitative side of things, let me explain what you call a "problem" at the end of your message.
Take a subcritical neutron star, so its radius Rn (in blue in the picture below) is greater than its Schwarzschild radius Rs (in red) and feed it with some additional matter from a companion star, as explained in the papers provided.
The radius of the star Rn will grow, but its Schwarzschild radius Rs will grow faster.
They both meet at the dotted black radius.
When Rn = Rs, the star transform into a black hole. That's it.
This is what Petit calls the "geometric criticality".
But as noted by Karl Schwarzschild as soon as 1916, then later by Tolman, Oppenheimer and Volkoff, and again by Petit, the pressure at the center of the star will quickly increase to infinity before such geometric criticality is reached. This is the sense of the TOV equation and and its signification (the red critical curve) in diagrams that I shared in a previous post.
Obviously "infinity" is not something that is truly physical. Petit claims that at this point constants of physics change in this high-density state of the neutron star, like in the relativistic radiation-dominated era of the universe, according to his VSL theory (see on Wikipedia for a quick reference). Pressure and speed of light both increase toward infinity, and beyond some threshold, before reaching such "infinity", mass inversion occur at the center. Not all the mass of the star is necessarily inverted and transferred in the negative sector through this "cosmic plughole", only the mass in excess. This is a transient phenomenon. But in a the case of a much violent event (e.g. merger of two neutron stars) such mass inversion could be total. The whole mass inversion of such bodies in a snap would generate gravitational waves that would be detected and interpreted along the lines of the mainstream model as a "black hole merger" for exemple, by instruments such as LIGO.
But what is important to note is such physical criticality triggering this mechanism appears before the geometrical criticality (the dotted line above) is ever reached. So the "black hole state" Rn = Rs never occurs.
As for the question "why no white holes (white fountains)? In fact there is no stars, no planets, hence no galaxies in the negative sector. No elements heavier than anti-hydrogen and anti-helium of negative mass. This is because the space scale factor of the negative sector is in a much more contracted state than the space scale factor of the positive sector. So its cooling time is equal to the age of the universe. The negative sector will stay that way, as its cosmic expansion is decelerating, while ours is accelerating (the negative pressure due to the overall energy density of the negative sector, aka dark energy, is what produces the observed acceleration of the cosmic expansion). This means that negative mass as gas in proto-nebulae radiating in the infrared spectrum in this sector will never cool down enough to coalesce, so it will never produce stars. No stars, no heavier elements. Therefore no planets and no life in the negative sector.
By the way, a side note about the expansion of the positive sector accelerating by the negative pressure of the other one. He never thought of it, but Petit almost predicted the accelerating expansion of the universe as soon as 2001: figure 13 page 18 of his conference paper:
Curve R for the accelerating positive sector, and R for the decelerating negative sector. He didn't especially notice this prediction at that time thinking the curve would asymptotically become straight (no acceleration at all, one of the three classical Friedmann predictions) which was given for ρ/ρ = 65 in this analytic calculation. Obviously higher ratios would produce a stronger repulsion between the two entities, with an accelerating expansion occurring in our epoch too. Simple remark
To be fair, the exact solution for the rate of the cosmic acceleration, when we consider that dark energy may be due to a negative mass content in the universe (and a zero cosmological constant!) has been actually provided by William Bonnor in 1989, who didn't notice neither at that time. See Bonnor's paper published in General Relativity and Gravitation, section 4.3, page 1153.
To come back to the current subject, when the mass of a neutron star, of some part of it, is inverted and transferred in this negative sector as negative mass, it doesn't stay "there" as is. Due to the very different space scale factors, matter transferred there has to appear at a relativistic speed in order to conserve energy (a mechanism called by Petit "the Gulliver effect" as particles from our sector grafted suddenly in the negative one appear to have a spatial extension their Compton wavelength much greater than all particles of this universe). So in the case of the inverted neutron star, the mass transferred is quickly scattered to the four winds in the void of the negative sector.
I must admit that the leaking neutron star model is more advanced than the "quasar model" and the subcritical yet giant object at the center of the galaxy, which are still crude ideas that follow on from the neutron star developments, for the latter. Hence your unanswered questions about quantitative predictions. I will continue mull over this magnetic field problem with a low-density ball of plasma though.
One morte thing: Russian researchers A. A. Grib and Yu. V. Pavlov independently published in 2010 a paper in International Journal of Modern Physics D in which they also claim that the energy of particles reverses when they cross the event horizon of a black hole (equivalent to the throat surface in Petit's model): https://arxiv.org/abs/1008.3657 -
#23 by meberbs on 02 May, 2019 19:23
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meberbs, thanks for having taking time to look at the papers, even quickly. On the qualitative side of things, let me explain what you call a "problem" at the end of your message.
The picture you attached is what made it clear beyond doubt that Petit's claim was mathematically inconsistent.
Take a subcritical neutron star, so its radius Rn (in blue in the picture below) is greater than its Schwarzschild radius Rs (in red) and feed it with some additional matter from a companion star, as explained in the papers provided.
The radius of the star Rn will grow, but its Schwarzschild radius Rs will grow faster.
They both meet at the dotted black radius.
When Rn = Rs, the star transform into a black hole. That's it.
This is what Petit calls the "geometric criticality".
He clearly states that the problem happens when Rn/Rs = sqrt(8/9) however, that condition cannot be reached until after the object has already become a black whole. It is clear from the diagram you provided that Rn > Rs for an object that is not a black hole, and therefore Rn/Rs is greater than 1.
If someone claims that the problem also exists for Rn/Rs greater than 1 (which the paper appears to do), then they have clearly made a mistake, because in that case, the Earth should have infinite pressure at the core which is a clearly wrong result.
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#24 by flux_capacitor on 02 May, 2019 21:15
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The picture you attached is what made it clear beyond doubt that Petit's claim was mathematically inconsistent.
He clearly states that the problem happens when Rn/Rs = sqrt(8/9) however, that condition cannot be reached until after the object has already become a black whole. It is clear from the diagram you provided that Rn > Rs for an object that is not a black hole, and therefore Rn/Rs is greater than 1.
If someone claims that the problem also exists for Rn/Rs greater than 1 (which the paper appears to do), then they have clearly made a mistake, because in that case, the Earth should have infinite pressure at the core which is a clearly wrong result.
OMG you are right! I provided an erroneous (previous) version of the paper, I am so confused.
Actually Karl Schwarzschild found that the critical value is Ř = √(8/9) (not the ratio Rn/Rs, which can take multiple values!). Ř is fixed for any given mass because it depends on the mass density ρ of the star, not on its mass M. And the Schwarzschild model, as well as the TOV model, assume that this mass increases with a constant density.
The correct graphical representation of the TOV solution is then:
Actually the pressure shown in the graphics is the pressure inside the star, function of the distance from its center, for given external radii Rn = 0.4 Ř, 0.5 Ř, 0.6 Ř, 0.7 Ř, 0.8 Ř, 0.9 Ř, 0.9428 Ř (physical criticality, leaking neutron star) and Ř (geometrical criticality, black hole) in the figure on the left, plus intermediary curves between these two criticalities in the figure on the right, which shows how the pressure dramatically increases beyond unimaginable values.
At the left, the pressure at it center (R = 0).
Schwarzschild discovered that the pressure at the center of the star indeed reaches infinity BEFORE the critical radius Ř is reached (i.e. before Rs caught up with Rn and they both meet) so indeed before the geometric criticality that transforms the star into a black hole is ever reached.
Petit knows it, as he correctly described this in his subtitled video Janus #22 Part 3 (published on YouTube 19 September 2017) at exactly 38mn00s.
I think I have not the good version of the papers. I am very sorry to have published a wrong graph before. Hopefully you were here to notice meberbs, thank you for that. At least one who follows
Admittedly, 0.9428 seems intuitively "very close" to 1. So could we simply neglect this result and assimilate this physical criticality to the geometric one? Not really, because mass is proportional to volume, and the volume is function of the cube of the radius of the star. So the discrepancy between the physical criticality of the leaking neutron star and the geometric criticality of the black hole is actually something like about 20%. -
#25 by flux_capacitor on 21 May, 2019 10:44
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Another fringe scientist, Eric J. Lerner, thinks too that the M87 object is not a supermassive blackhole but a subcritical MHD object or "plasmoid" with peculiar behavior and shape, a "quasi black hole" as he also calls it.
This would be the same kind of plasmoid Lerner and his team have observed for decades in the Dense Plasma Focus machine:
He made 5 short videos (3-4 mn each) explaining why.
In the 1st video, Lerner starts with a (rather specious according to me) argument for why the object could not be a black hole and why black holes cannot exist. IMHO, the issue of the freezing time-coordinate of a free-falling test particle, watched by a distant observer, is not something that applies to the observability of the object itself before it has been formed, but to external objects (dust and gas) falling onto the event horizon once the black hole has been formed already.
The 2nd video is more interesting. Like in a DPF plasmoid, electric currents circle within the object, which also rotates at high speed. At this stage, electric currents and magnetic field lines are rather orthogonal. Their combination produces Lorentz forces that remove energy from the spinning object by decreasing its angular momentum, through an electromagnetic breaking effect. This has two consequences: first, having less energy and less centrifugal force, a radial compression occurs: the spinning object becomes smaller. And as the magnetic flux is conserved, the magnetic field strengthens at the same time. Then, the electric currents tend to align with these magnetic field lines, and the electromagnetic forces decrease (the cross product of I and B becomes negligible) as well as the breaking effect, down to a point where the various forces (due to the gravitational pull, centrifugal force, thermal counter-pressure, the force due to the magnetic field) are all balanced, and the compression stops.
In the 3rd video, Lerner describes the peculiar form of such a plasmoid: it has a toroidal shape with a small throat circle, like a donut. He makes predictions about the "supermassive black hole" at the center of the milky way, Sagittarius A*: as we observe it from the side, the donut has not at all the shape of a flat accretion disk with a dark, non-emissive black disk in its center, hence researchers would struggle imaging it "correctly".
Lerner then criticizes the "incorrect MHD approximation" in the 4th video. According to him, magnetohydrodynamics correctly predicts the behavior of dense collisional plasmas, as the thermonuclear plasma inside a star like the Sun (where relative density ~ 1) where magnetic field is high but not enormous, while it is not the case anymore in low density, low collisional space plasmas with a giant magnetic field like in these objects (Lerner thinks the M87 object density is less than that of the air we are breathing). In particular, in this low density, low collision, powerful magnetic field scenario, charged particles move along the magnetic field lines, spiraling tightly around them like a corkscrew, so electric currents tend to flow in the same direction as the magnetic field lines, and not across them which is where the MHD approximation fails.
In the 5th video, Lerner explains that electrons and positive ions are expelled away of the object along its axis at relativistic speeds, in two opposite directions as two electrically charged collimated rays. Exactly like the plasmoids observed in a dense plasma focus, and what is observed in the universe with quasars and active galactic nuclei. Therefore, a better understanding of such astrophysical phenomena, quite distant in the universe, could paradoxically help us solve the energy crisis here on Earth, thanks to the development of a compact aneutronic fusion reactor like the Dense Plasma Focus.
So to sum up: like Petit, Lerner thinks the object is a plasmoid and not a black hole; that it is an MHD object of peculiar behavior; that it takes its energy from its magnetic field; and that it is directly related to quasars and AGN. Their interpretation differ as to where the energy comes from initially (not really explained by Lerner, while it is a magnetic flux compression of galactic scale in Petit's bimetric scenario, where density waves focus at the center of the galaxy gathering the magnetic field lines with them a phenomenon triggered by fluctuations of the two metrics).
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#26 by flux_capacitor on 21 May, 2019 11:10
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A last remark about the image of the M87 object, that is not an optical one but has been "reconstructed" with radio-telescopes using various frequencies.
If what is observed is a plasmoid with a gravitational redshift of 4.2, this means that the wavelength of the central object is multiplied by 4.2
Suppose that the emitted radiation of such object has a wavelength of about 1 mm. Then, the central object is "seen" with a wavelength of 4.2 mm
However, the radio telescopes that produced this image have a bandwidth that is clipped for wavelengths higher than 3 mm, so they couldn't "see" the central part, which is still emissive yet appears artificially black in the famous "picture" released, due to the gravitational redshift that moves the central wavelength outside of the capped bandwidth of the radio-telescopes used up to now.
Still unconfirmed information from researchers working directly in the field points to ongoing observations with other radio-telescopes that are capable to image up to 10mm wavelength, that would not show such black central disc.
If this object is really a black hole, it has an infinite gravitational redshift and its central part will be black whatever the observed frequency. If it is on the contrary a "Lerner-Petit plasmoid" it will appear darker at the center but still emissive. -
#27 by dustinthewind on 19 Jun, 2019 18:29
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The reason the ions are ejected from the magnetic poles I think is because of wobble in said magnetic field. With wobble the greatest change in the magnetic field is at the poles. So they are blasted by radiation which is the change in the magnetic field, propelling them to relativistic velocities. It's interesting that a black hole maintains a magnetic field. Is it supposed to maintain this magnetic field from current within the event horizon or some how the current that maintains the magnetic field is generated outside the event horizon. If within the horizion this is interesting because information from within the event horizon about the current would be being carried outside the event horizion via the magnetic field. By that logic the magnetic field must be being generated from outside the event horizion.
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#28 by meberbs on 22 Jun, 2019 06:34
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Seeing a new post in this thread made me look again and this time I was able to find something that directly addresses pressure inside a uniform density star (last page or so):
http://www.tapir.caltech.edu/~chirata/ph236/2011-12/lec18.pdf
The treatment here indicates that the result of infinite pressure is not an actual problem with GR, there is no contradiction or similar with this result. After reading this, I can more clearly some of the issues I see:
-Petit is basically assuming a constant density, but in real life matter generally is compressible and density is not constant (For neutron stars, the form of matter changes with depth.)
-As stated in the paper I linked, the limit basically just states that there is only so much matter that can exist in a uniform density object. The paper states that for an object that decreases in density outwards the limiting ratio always remains valid. (Note they use a dimensionless Mass to Radius ratio, which can be generalized to non-uniform density stars.)
-A fundamental limit like this basically means that you would not be able to keep adding more mass at constant density. This seems strange, but far stranger things exist in physics relative to human intuition. You have to remember in this case that the matter is literally bending space-time itself.
-Based on this I do not find Petit's claim to be even plausible lines of argument, let alone convincing.
As to magnetic fields, they are certainly can be present around black holes, the issue is why would they perfectly balance the pressure to keep the object just above the size of a black hole for all the different sizes of black hole we know of.
Also, a couple comments on the other videos you posted, note than I have only read your summaries, I don't feel it would be worth my time to watch them. In the 1st video, Lerner starts with a (rather specious according to me) argument for why the object could not be a black hole and why black holes cannot exist. IMHO, the issue of the freezing time-coordinate of a free-falling test particle, watched by a distant observer, is not something that applies to the observability of the object itself before it has been formed, but to external objects (dust and gas) falling onto the event horizon once the black hole has been formed already.
This sound like he makes a common argument against black holes, which falls solidly into the category of "based on a fundamental misunderstanding." Someone asking about this when learning GR is reasonable, it is a good question. Someone stating that black holes don't exist because of this simply does not understand what they are talking about and does not recognize that they still need to study the subject in question more. It sets their credibility on this and related topics somewhere around zero.
It sounds like most of the rest of the videos don't even describe actual arguments against black holes. The third one from your description basically says that when Sgr A* results come out from the EHT, if it matches scientists expectations, then he is simply wrong. GR works well in a variety of circumstances, and one black hole was successfully imaged, so there is little expectation that the next black hole image will be a surprise.Suppose that the emitted radiation of such object has a wavelength of about 1 mm. Then, the central object is "seen" with a wavelength of 4.2 mm
The imaged matter in question would be emitting in a broad spectrum fashion. You are currently making a nonsensical assumption about part of the object emitting only a single frequency using made up numbers. Some of your information is just completely off target, because you are talking about telescopes observing at "various" frequencies, but by the nature of the interferometry they used, the measurements all had to be made at a single frequency.
However, the radio telescopes that produced this image have a bandwidth that is clipped for wavelengths higher than 3 mm, so they couldn't "see" the central part, which is still emissive yet appears artificially black in the famous "picture" released, due to the gravitational redshift that moves the central wavelength outside of the capped bandwidth of the radio-telescopes used up to now.
To be fair, the exact solution for the rate of the cosmic acceleration, when we consider that dark energy may be due to a negative mass content in the universe (and a zero cosmological constant!) has been actually provided by William Bonnor in 1989, who didn't notice neither at that time. See