decraig

Just 2 days ago, Jan 8, 2016, the long awaited follow up paper arrived.

http://arxiv.org/abs/1601.00921

Hawking, et al, describe a different sort of animal, not a black hole at all, in the sense that a black hole is defined as a region of space from which nothing can escape, not even light.

I suggest naming this new object a "Foo' Hole." In case it has escaped notice, Foo' Holes and Black Holes are mutually exclusive theoretical objects.

Should Hawking argue his theory on this site will he also be suspended, as I, by a moderator operating far outside his pay grade?

Later. Much, much later.

No, you have not and once again you evaded my question. You're doing the same thing as cranks.

 

Do you or do you not agree that the standard black hole model is a well established part of mainstream physics and that current scientific consensus holds black holes to be consistent with the theory of general relativity and current observations?

 

There is an important difference between acknowledging what the status of scientific consensus says and questioning its correctness, crackpots and science deniers often wants to blur and muddle this distinction because it gains them false credibility and casts doubts on opponents.

 

I am starting to suspect that you on purpose misinterpret my points and avoid to answer my raised arguments of the above.

 

There is nothing wrong with my references in regard to the content of my arguments!

 

Now, I have asked you to clarify your position more than once, why are you so unwilling to comply to this simple request?

You certainly do have a lot of questions. Can you explain your obsession with taking votes?

Yes, but if the radius is changing with time (which is what happens in gravitation), the metric would also change with time.

I believe you refer to the radial coordinate.

But now I don't know what kind of solution to the field equations you might be talking about. Assuming spherical symmetry you want something like this:

[math]c^2d \tau ^2 = f(r,t)c^2dt^2 - g(r,t)dx^2 - d \Omega ^2 [/math]

What does that look like? It seems to violate Birkhoff's theorem...

http://en.wikipedia.org/wiki/Birkhoff's_theorem_(relativity)

It is possible in principle. If a microscopic black hole was created, it would decay almost immediately. There is no evidence it has happened: http://arxiv.org/abs/1012.3375

Identify the principle, please.

The Schwarzschild metric can vary with time if there is motion, i.e if you have a function r(t). There is certainly motion when the core of a supernova compresses into a singularity.

If the metric changes with time, it is not the Schwarzschild metric. It would be a different metric.

This is the Schwarzschild metric:

Notice there are no terms containing 't' in the metric coefficients. A metric coefficient is the stuff in each term standing in front of ct^2, dr^2, dtheta^2 and dphi^2.

The asymmetrical collapse of various interacting masses to form a symmetrical black hole was addressed in the 60s by people like Wheeler , Thorne and Zel'dovich ( who called them 'frozen stars' as Wheeler's term , black hole, has vulgar connotations in Russian ). And no I can't quote references, do a search If you're interested. But you won't, your mind is made up, no sense peeking around the blinders!

 

Is your intent to re-do the past 50 yrs of high energy gravitational physics and cosmology ( as these theories apply to the very early universe as well )?

 

If so, you should give it a rest as I really don't think you're at the same level as the three named gentlemen, plus Oppenheimer, Novikov, Penrose and Hawking. You may well have been drunk when you started this thread.

You seem to have misunderstood. However, it is true that asymmetrical, irrotational matter will approach spherical symmetry under mutual gravitational attraction. This is due to gravitational time dilation where ingoing velocities of particles slow according to an external observer as they approach the Schwarzschild radius.

This was demonstrated by Rodger Penrose.

Penrose, Gravitational Collapse and Space-Time Singularities

Physical Review Letters Vol. 14-3 1965

Penrose examines the dynamics of matter external to the Schwarzschild radius. He does not examine the dynamics of formation. Your words, “to form a symmetrical black hole,” seem to be something extra you added in expectation.

Penrose continues with the post formation dynamics, ignoring the critical formation dynamics.

No one in 1965 had a formation solution. They skipped it. They made a lot of progress explaining what things look like afterwards, but couldn’t find a way to get there. By all evidence this state of affairs persists today. Not properly understood, it is a source of militant denial. It ranges from accusations that I am wearing blinkers, accusing me of not conducting research--and by others, deliberate fraud.

Oh no, you do not get to just brush this under the carpet and then request for new references. I did provide evidence on scientific consensus in the matter of black holes and at this point I think you really need to clarify your position about it much much better.

 

Do you or do you not agree that the standard black hole model is a well established part of mainstream physics and that current scientific consensus holds black holes to be consistent with the theory of general relativity and current observations?

 

And IF you don't agree that the current status of scientific consensus is as I have represented it, then you need to explain what's wrong with my references and provide evidence of the negative nature of scientific consensus regarding the standard black hole model and any falsifying observations that have been made

I already explained what's wrong with your referencing. You're doing the same thing as the other guy.

You're referenced an article. You did not cite any of its content. Did you get beyond the title?

Should you have bothered to read it, you would know that the article addresses experimental evidence that would distinguish between dark clusters and black holes, but not highly condensed matter and black holes.

Strange has something better to offer.

 

That is because it is an approximation to the real world using simplifying assumptions (as are all solutions to the EFE). More realistic situations (e.g. a black hole absorbing mass, or two black holes merging) can be modelled using numerical methods.

Of course; there is a distinction. Consider you already have a spherical black hole of mass M, and we throw a small mass, m at it. Does m cross the event horizon?

The mass, m perturbs our spherical black hole solution; the exact solution is not spherically symmetric.

So we use some numerical method. By experience we know it's not exact either, and subject to modeling approximation and floating point round-off. But the error introduced may itself be analytical or subject to numerical analysis.

I write a program to solve the n-body problem of multiple masses under mutual gravitational attraction. Each mass follows some curved path that I approximate with very small straight line section. To test the model I use a large central mass, and a small mass in circular orbit. Over time the orbital radius increased. I erroneously conclude that gravitational energy is not constant over time. dE/dt is greater than or equal to zero. This is a lot different than dE/dt=0. Making the straight line segments smaller does not change to result. Replacing the straight lines with polynomial approximational results in dE/dt=~0.

For black holes, the region of interest is near Rs. The functions of interest are gtt( r ) = 1/(1- r/Rs) and grr( r ) =1- r/Rs where r is very close in magnitude to Rs. r-Rs=epsilon, epsilon-->0.

Our numerical error will never be less than epsilon but we might try a change of coordinates, u=u(gtt,grr) and v=v(gtt,grr). We can then try doing the numerology in u and v than translate the results back to gtt and grr and hope that calculating gtt doesn't give us an NAN or stack overflow.

[modnote] decraig, if you think that imatfaal is incorrect, address exactly where it is that his information falls short. Do not simply wave off the post by insulting his intelligence or simply saying that is nonsense - especially when it doesn't actually appear to be nonsense at all.

 

Also, if you are going to report someone for apparently insulting you - though I truly don't see it - perhaps you should try and and avoid the same behavior?

 

Lastly, this thread is getting tiresome and I think people are quickly losing patience with your inability to consider the information that is actually out there refuting your ideas. People have linked you papers and they have provided you with good information. You cannot keep ignoring them because you don't like it or you don't have access to the papers that people have linked you and if you do, then expect this to be closed (as I have already warned you). [/modnote]

I have, many times already. And I just keep on getting false information, red herrings consisting of either irrelevant information of references that even contradict the claim made of them. Look for yourself.

As to your second remark that I have put in bold, this is far from correct. Please show me an example where I have done this. Produce this information that is "actually out there".

This was the intent of this thread, and no one have yet manged to produced it, yet insist that it is there. If unsupported claims are the stock in trade in this forum, why call it a science forum.

I have enumerated approximately 6 points, unverifed that could falsify a conjecture of non-formation of black holes. I haven't seen any of these points raised.

 

Some claims involving black holes may be pseudoscience, but black holes themselves are not.

Black holes have a mathematical framework surrounding them, such as the Schwarzschild metric:

[latex]ds^2=\left(1-\frac{2GM}{rc^2}\right)dt^2-\left(1-\frac{2GM}{rc^2}\right)^{-1}dr^2-r^2d\theta ^2 - r^2 sin^2\theta \ d\phi ^2[/latex]

and the event horizon radius for a Schwarzschild black hole (Schwarzschild radius) :

[latex]R_s=\frac{2GM}{c^2}[/latex]

Pseudoscience has no mathematics (or no scientific evidence for mathematical claims), unlike black holes.

There is lots of evidence for black holes, such as supernovas. If a star is massive enough, it will collapse into a supernova. The matter left behind will have to compress into a black hole, and that is what happens.

Notice that the Schwarzschild metric is invariant with time (it doesn't change over time).

This metric solution is insufficient evidence of physical black holes formatationbecause to make one, the metric has to change with time. It looks good on paper and the drawings are attractive, but the map is not the territory.

Do you see that you have to have a means of formation before you can justify models of existent black holes, or alternatively supply experimental evidence?

I've already addressed this.

I shouldn't really have to provide a reference on scientific consensus in the matter of black holes, but here you go:

 

"Objects whose gravity fields are too strong for light to escape were first considered in the 18th century by John Michell and Pierre-Simon Laplace. The first modern solution of general relativity that would characterize a black hole was found by Karl Schwarzschild in 1916, although its interpretation as a region of space from which nothing can escape was first published by David Finkelstein in 1958. Long considered a mathematical curiosity, it was during the 1960s that theoretical work showed black holes were a generic prediction of general relativity. The discovery of neutron stars sparked interest in gravitationally collapsed compact objects as a possible astrophysical reality.

 

Black holes of stellar mass are expected to form when very massive stars collapse at the end of their life cycle. After a black hole has formed it can continue to grow by absorbing mass from its surroundings. By absorbing other stars and merging with other black holes, supermassive black holes of millions of solar masses may form. There is general consensus that supermassive black holes exist in the centers of most galaxies."

http://en.wikipedia.org/wiki/Black_hole

 

 

Or if you requested a reference that scientific work has been done to provide evidence of black holes:

 

"High Proper Motion Stars in the Vicinity of Sgr A*: Evidence for a Supermassive Black Hole at the Center of Our Galaxy

Over a two year period (1995-1997), we have conducted a diffraction-limited imaging study at 2.2 microns of the inner 6"x6" of the Galaxy's central stellar cluster using the Keck 10-m telescope. The K band images obtained reveal a large population of faint stars. We use an unbiased approach for identifying and selecting stars to be included in this proper motion study, which results in a sample of 90 stars with brightness ranging from K=9-17 and velocities as large as 1,400+-100 km/sec. Compared to earlier work (Eckart et al. 1997; Genzel et al. 1997), the source confusion is reduced by a factor of 9, the number of stars with proper motion measurement in the central 25 arcsec^2 of our galaxy is doubled, and the accuracy of the velocity measurements in the central 1 arcsec^2 is improved by a factor of 4. The peaks of both the stellar surface density and the velocity dispersion are consistent with the position of the unusual radio source and blackhole candidate, Sgr A*, suggesting that Sgr A* is coincident (+-0."1) with the dynamical center of the Galaxy. As a function of distance from Sgr A*, the velocity dispersion displays a falloff well fit by Keplerian motion about a central dark mass of 2.6(+-0.2)x10^6 Mo confined to a volume of at most 10^-6 pc^3, consistent with earlier results. Although uncertainties in the measurements mathematically allow for the matter to be distributed over this volume as a cluster, no realistic cluster is physically tenable. Thus, independent of the presence of Sgr A*, the large inferred central density of at least 10^12 Mo/pc^3, which exceeds the volume-averaged mass densities found at the center of any other galaxy, leads us to the conclusion that our Galaxy harbors a massive central black hole."

http://arxiv.org/abs/astro-ph/9807210

I agree. You should not provide a consensus--provide evidence or scholarly papers instead. The ideal of science appeals to evidence not authority.

As to your reference I have put in bold: Have you read the article. Can you cite the section where they provide distinguish evidence between BHs and highly collapsed matter? Is it even addressed?

Evidence is evidence, but distinguishing evidence is what is require here.

Don't put words in my mouth decraig. I did not mention Newton and I understand the math of GR quite well. I also like to believe I understand some Physics. All Relativity does is tell us how the same event 'looks' to different observers or frames. The fact that gravitational collapse 'seems' to not happen in a non-local frame does not mean it doesn't happen in a local frame. The local observer does pass through the mathematical point of no return ( event horizon ) and on to the singularity. Now I would claim that this singularity is non-physical but you having faith in the math of GR, must consider it real.

I'm glade you know GR quite well.

All coordinate charts are nonlocal frames at points over their domain. By putting quotes around 'seems' are you implying that coordinate charts should not be used describe physics?

Interesting. Do think that all charts with singular points are nonphysical?

 

 

 

My credibility is already completely shot to pieces - so I have no need to play silly games with trolls. I have read quite recently Sean Carroll's notes on GR and that seems similar; but I am sure you are referring to something far more abstruse. The fact that EF coordinates are invertible - is one of the major clues that the singularity is non-physical; a fact you still seem to be missing.

 

So which bit is confused?

 

 

Do you think this is wrong? Makes sense to me and I am pretty sure I am correct.

 

Perhaps a little jokey - but still correct. EF coordinates introduces tortoise coordinates and changed coordinate time - this gives different solutions to radial null curves for infalling and outfalling

 

The bit you keep arguing - and no matter how insulting, trollish, and stubborn your posts become, this is the crux of the matter from your first post onwards. And it remains correct.

 

You are quite right that "mapping to EF coordinates does not affect physical results" ; so why in heaven do you not understand that this shows incontrovertibly that the Schild coordinate singularity at the event horizon must be non-physical. If it disappears in EF or Kruskal coordinates - and a coordinate change cannot affect physical results - then the only conclusion is that it must be non-physical!

pure nonsense

Without the moon, life on earth would be no more complex than bacterium applying accepted theory; the moon reduces the excursion of obliquity (axial tilt). Without the moon the axial tilt could vary as much as 80 degrees.

With the moon the obliquity varies from about 22 to 24 degrees over a period of 40K years.

However, there is some disagreement. http://io9.com/5829438/earth-doesnt-need-the-moon

 

No - that is Schwarzchild plus charge; or more accurately R-N in the limiting scenario where charge goes to zero reduces to the Schwarzchild metric( and for an uncharged BH you would still get a mathematical singularity at the EH). E-F coordinates are more complex in that they play around with t and actually take on a different form for ingoing particles and outgoing - there is no doubt that S'child are more intuitive, beautiful etc - but they just do not work at the EH

Based upon these confused remarks, I don't think physics is your calling. You are not positively contributing to this thread but just trying to win an argument without supplying merit. This repeated invokation of Eddington-Finkelstein coordinates is immaterial. Per canon, mapping to EF coordinates does not affect physical results. The coordinate map between the Schwarzschild and EF charts is invertible over the coordinates range involved. Look it up. EF yields the same time for black hole formation as S. This is introductory level general relativity.

If you are versed in elementary general relativity you will be able to name the canon to which I referred. This is a challenge to your credibility.

"My science teacher vaguely defined [energy] as the ability to do work."

I don't think this is a very good definition, and says "energy is the ability to do energy".

Formally, work has units of energy. In terms of forces, W = Fd. Work is force applied over a distance.

It would be better so say that energy has at least two forms, kinetic and potential, and that one form can be become another.

---------------------------------------------------

On energy conservation:

1) The energy of a system is not conserved. Energy can enter or escape the system. Rather, we might formulate what is called a 'continuity equation'. The change in energy of a system plus the momentum flux out of the system is constant.

To keep it simple, envision a tesseract. The bottom face of the tesseract is the system at some time t_0. The top face is the system at some future time t_1. At t_0 the system has some initial energy. At some future time, t_1, the system will have another amount of energy.

Now look at the remaining 6 faces. A 'face' on a tesseract is a cube. These 6 remaining cubes have two sides with units of length. The remaining side is an interval of time. The difference in energy of the top and bottom faces plus the differences in momentum of the remaining opposing faces is zero. This is a continuity equation.

2) An observer undergoing a change in velocity will find the energy of a system is not conserved; energy is not conserved under a general Galilean transformation; a change in velocity. This is because the kinetic energy has changed.

I would think you would pick up factors of b all over the place in your equations and so generally we won't have invariance in the sense that the laws are totally insensitive to this rescaling. You could also try thinking about this in terms of group theory and the representations of the Lorentz group, I guess.

 

They are invariant in the sense that we can make some other choice of units when defining the value of c and the physics won't change, of course being careful with the other constants that we have.

Doh! Yes, replacing c with bc is the obvious part I missed, such that, if b canels on both sides of a set of equations, then those equations are invariant under rescaling of c.

There is some interesting background on the Painleve-Gullstrand coordinates on Wikipedia. I hadn't realised that Painleve tried to argue that they showed GR to be wrong/incomplete and that Einstein rejected it as a solution to the EFE. (It wasn't until later that Lemaitre showed they were equivalent to to Schwarzschild coordinates.)

http://en.wikipedia.org/wiki/Gullstrand%E2%80%93Painlev%C3%A9_coordinates

 

I think the Schwarzschild metric is the only solution to the Einstein Field Equations that has a singularity at the Schwarzschild radius (but I could be wrong). All the other commonly used coordinates (P-G, Eddington–Finkelstein, Kruskal–Szekeres, Lemaitre) avoid it.

Thanks, for that. Add electric charge and you get the Reissner-Nordstrom metric, http://en.wikipedia.org/wiki/Reissner%E2%80%93Nordstr%C3%B6m_metric, with two critical radii.

Reissner–Nordström

http://en.wikipedia.org/wiki/Smart_bullet#Changing_trajectory

The title should have been:

"Is physics invariant under global regauging of c?"

The geometrical constant relating dimensions of time and distance is c=~300,000 km/sec.

Are the laws of physics invariant under regauging of c; that is

[math]c \leftarrow c' = b c[/math]

where b is real scalar?

I'm sure there's something obvious I'm missing.

davidivad.

Lets start over. If you want to make some interesting plots you can start here. http://en.wikipedia.org/wiki/Schwarzschild_metric

Plot the [math]dt^2[/math] and [math]dx^2[/math] coefficients as a function of [math]r/r_{s}[/math].

Even more interesting, in the way of testing my assertions, try looking at http://arxiv.org/abs/gr-qc/0201037.

I haven't yet read it. The author claims to have some interesting coordinates that are singularity-free at [math]r_s[/math]. I have little doubt that he does---but I just haven't read it.

This really is an issue in modern mythology. It's like the telephone game--each retelling of the story embellishes the original message--even among professionals. It is driven by the human desire to reaquire the mysterious, lost when most of the scientific community embraced atheism.

Apparenty, for A, antisymmetric, [math]A = (1/n!) A_{[\mu \nu \rho \sigma]}[/math].

[math]A = a \epsilon[/math]

and

[math] A' = |J| A [/math]

where |J| is the determinant of the Jacobian.

But I can't find a reference to verify.

GUT models suggest that proton do indeed decay, but this is now rather speculative and for sure they have a very long lifetime.

What does the picture look like If we assume protons do not decay?

If you recall, the model gives a visual picture. When enough energy is added to bound pair of quarks, the gluon breaks resulting in a quark-antiquark pair.

As far as I can see, sufficient gravitational tension would continually tear apart [math]q\overline{q}[/math] pairs resulting in more pairs.

 

without a response, i must then assume you cannot do the math.

i can only logically assume you have read a few articles and stitched them into an incomplete idea.

this is where math comes in.

that is a shame as i might have been able to help you realise your idea with graphics.

That would be a little too sleezy for my tastes

So far I don't consider you to have gotten even close to shot down the scientific consensus in the matter of black holes. Further more I don't have to provide evidence for established mainstream physics, that has already been done by professional scientists in that area of research. If you on the other hand want to disprove their work, then you are the one in need of providing evidence, and so far your evidence is insufficient.

Reference, please,

The event horizon, no matter what co-oedinate system is used, is a strictly mathematical construct. THERE IS NOTHING ACTUALLY THERE !

 

Decraig, you need to consider the physicality of the situation not just the mathematics. You say you have 30 yrs experience with the mathematics describing the situation and I say that there is no force or mechanism that can stop the collapse of a massive star once gravity overcomes nuclear radiation pressure and electron and neutron degeneracy.

 

So again I ask you, not for mathematical proof, which may or may not be valid ( we have estabilished that GR is only valid within certain limits, have we not ? ), but for physical options.

If you don't like mathematical constructions, don't defer to general relativity. Now that you throw away mathematics, which is what you are doing, what are you going to do?

You also think, in the Newtonian manner that, that collapse to a black hole is inescapable. Get over Newton.

decraig;

 

can you describe what you think the coordinate singularities are doing to affect the schwartzchild radius directly?

 

if you could explain your concept of singularity for me?

this might help me understand.

The coordinate singularities do not effect the horizon radius. Based upon this question I don't think I could help with your second question without some knowledge of differential geometry.

------------------------------------------------------------------------------------------------------------------

imatfall, You demand I response to your post #49:

I’ve been overwhelmed by garbage, and so have tried to ignore irrational arguments demanding attention—but you asked for it.

You: Could you be more specific concerning where you believe those articles aid your argument? Most of this thread has been objecting to the concept of black holes through a classical argument (which I believe was flawed but nonetheless) with a few mentions of the information paradox. However, these articles - not exactly representative of the subject, basically by two researchers and various colleagues - are firstly not dismissive of the general notion of black holes as you seem to be, secondly are all trying to breach the as yet impassable division between the semi-classical approximations of black hole formation and a full quantum gravity explanation, and thirdly do not address the existence of black holes but rather probe the possibilities of their formation and the fact that we cannot at present provide a route of unitary transformation from infalling matter to a blackhole.

Your style of argument best belongs in the arena of debate rather than honest scientific inquiry. You did attempt to dismiss these articles, not on merit, but because there are few advancing the ideas contained. This is offensive. Here, you use words word such as “nonrepresentatibe,” only to obfuscate. This too is offensive. Can we please stick to science? This is where we attempt to justify claims rather than demanding disproof and raising straw men.

You: The GR basis of black holes Penrose/Hawking calculations has been shown above in the articles referenced by AJB - and there are regions of the universe within which there is such amount of mass within such a volume that we believe a blackhole per accepted these ideas is the only plausible explanation. We cannot go there to check - and frankly 'seeing is believing' went out of vogue in physics a few centuries ago - and other than that, the central volumes of spiral galaxies have all the predicted characteristics of black holes and continue to pass every test.

Again, “We believe” is not an argument. I’m too well healed to fall for your logical fallacies. This too is offensive. This one falls under “appeal to authority and the attempt to ostracize” You get two fallacy points for this one. More, you are incorrect to presume a black hole is the only plausible explanation without addressing physically measurable or theoretic difference of incipiants.

You: The fact that we cannot provide a method of formation that obeys the unitary rules of quantum mechanics would be intensely worrying if we had a functioning theory of quantum gravity - but we don't! The simplicity yet extreme conditions dictated by GR in the vicinity of a black hole may well be the clues required to get that theory - but you cannot use the absence of a pathway in an incomplete theory to throw away the mathematical formalism within GR and the observational evidence of black holes

Nonsense. I am not throwing away the mathematical formalism of general relativity nor ignoring observational evidence. A false accusation. This too is offensive.

And, no. I can, and do use the absence of a pathway to formation to argue that formation does not occur. Again with false accusation the logical fallacy. Again you give me offence. Please stop.

This has gone way off course. In future, I will not respond to your sort of rhetorical misdirection, but to science, reason, evidence and the honest persuit of knowledge.

ok. so you think protons decay.

imatfaal, on 18 Jan 2014 - 07:52 AM, said:

This first line of questions of first post is incorrect

http://ned.ipac.calt...ndy/frames.html

I give up. Where in this article is there a counterclaim distinguishing galactic-center black holes from highly condensed matter?

Have you even read the article??

what happens in one coordinate system happens in another up to the point where the coordinate map is poorly defined. What do you think happens in one coordinate system and not another?

What about 31.2?

Why don't you put some meat on the plate, imatfaal, instead of quoting chapter headings.

How does the proper time of an infalling observer compare to our Earthly clocks using your favorite nonsingular coordinates?