Black holes may never actually form..!

Idiot wind analysis. At least be honest. You're using the remote bookkeeper frame dependent Schwarzschild coordinates. Schwarzschild coordinates include local proper frame coordinates and the bookkeeper coordinates. The only thing you're doing is showing us that you don't know what you're talking about. Don't tell me what the coordinates predict since you don't have a clue by choice. Your natural philosophy is bullshit. If you think I'm not an authority on this particular subject then you really are a dunce. It doesn't matter who explains this to you because you don't give a crap what GR relativity predicts unless it fits your convoluted natural philosophy. Go away crank.

 

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Perhaps you missed my response in post #294.

To add to it, though: you can't get credit for something you aren't doing. You're not an astrophysicist and you aren't doing any physics. You aren't entitled to propose new theories for "credit".

There really isn't much ground to be had on the subject matter itself. You just repeat the same wrongs in slightly different ways, over and over again. What I find most interesting here is you; trying to decipher how much of what you say is serious and how much isn't - or if you just aren't even reading what you write. It's fascinating trying to decode it. When you suggest that naysayers should leave the thread, it presents quite an interesting dichotomy of open-eyed self-delusion.

 

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It's called physicis. They don't need to extrapolate anything. They just choose coordinates that are not singular at r=2M so they can make coherent predictions. RJBerry keeps claiming that the mathematics of GR predicts black holes can't form. This prediction is based on the remote frame dependent coordinates which you just came to realize don't actually make the prediction that black holes don't form in a finite amount of time. His claim that the math of GR predicts that is complete nonsense. It's simple stuff that he refuses to evaluate. Wonder why? So he can pretend to be a natural philosopher. I'm pretty sure a real natural philosopher could figure out why they're no such preferred coordinates. The only preference involved in choosing coordinates is choosing the best for making coherent predictions associated with the spacetime being evaluated. GR predicts RJBerry is a self serving crank. Somebody who is more interested in proving himself right rather than finding out he's full of crap. Like a real natural philosopher.

 

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It's only begging the question in the sense that any analysis of the inside of a black hole is begging the question. The inside of a black hole has no causal influence on any outside observer, and every link I've seen confirms that the collapsar model matches the predictions of GR outside the event horizon; the mathpages link actually says it's a pretty good way to think about the dynamics as observed from a distant perspective. In quantum mechanics, we enjoy a surplus of interpretations, so we get used to drawing distinctions between interpretations and theories. Anything that predicts identical results for all experiments is an interpretation, and competing interpretations are usually treated with a default minimum of credulity. For instance, I think the Quantum Bayesianism interpretation is completely absurd, but I wouldn't call its proponents cranks. Similarly, you and brucep might think the collapsar interpretation is a silly attempt to force a preferred reference frame on GR, but it seems over the top to say RJBeery is parroting factually incorrect statements without doing any physics.

Of course, all this goes out the window if evaporating black holes are not well-described as collapsars. This would be an experimentally relevant result, and a lot more interesting than the question of how much significance we should assign to the infinite Schwarzschild time at the event horizon. I wish I had the background to do the calculation myself, but barring that, I'm hoping someone else will either do it or link to a pre-existing solution. In fact, I think I can distill my curiosity into two questions:
1. Does an infalling observer cross the event horizon of an evaporating black hole in finite time?
2. If so, where is the crossing event in remote bookkeeper coordinates?
Until then, I don't get all the venom being thrown at RJBeery just for raising the discussion.

 

Maybe you didn't understand. I'll try again: RJ is claiming that there is no "behind the event horizon" by virtue of choosing not to analyze the predictions of the theory behind the event horizon.

Sure - and it goes on to say that the model utterly fails at/behind the event horizon by making predictions that contradict both GR and QM. The idea that reality stops at the event horizon just plain doesn't work, but RJ is claiming reality stops at the event horizon by virtue of choosing not to take the analysis any further. It's an arbitrary choice and circular reasoning.

Prevailing theory says that's a clear yes.

You can't use those coordinates to describe the event.

You're new, but you should be starting to see the reason: it's his attitude, not his raising the discussion. If you didn't read the opening post in the thread, you should. That will make it clear.

 

But we haven't seen the road, we've presumed its existence and then speculated on where it goes. Even the mathpages description of going to infinity and back to describe an event horizon's growth necessitates an event horizon to cross because the infalling particle's path is continuous. Start with the genesis event - how does the black hole form? I bet you're imagining a neutron star right on the brink of collapse one moment, immediately followed by a black hole with a substantial event horizon volume. Ask yourself, is that how physics works? Gravitational pressure on a uniform spherical mass is graded from the external surface to its maximum at the center of mass. The event horizon would begin as a zero-volume point, and there is nothing for matter to "pass through" in order for it to increase its volume from there.

Fednis, you might find this interesting:
https://www.physicsforums.com/threa...on-preclude-eh-formation.658300/#post-4193132

 

I agree on this but it would still only help answer the question of black holes in QM+GR. There's the larger issue of black holes in GR by itself.

Yeah the OP in this thread was uncharacteristically salty of me but it was a result, and not the cause, of people insisting that black holes exist (e.g. we can point at the sky and see black patches, coordinate changes, etc) even after I provide mainstream evidence that the subject is, at the very minimum, still under debate.

 

A "clear" yes? I don't understand why you would say this.

 

No, I do not think you're an authority on GR. Have you taken GR classes? I thought the answer was yes, but you seem to hold the absolutely indefensible misconception that event horizons can exist in an external observer's past light cone.

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Perhaps you'd like to retract that statement (or defend it) because to this point the only thing you've done after I pointed that out is to throw invectives like some kind of strange child.

 

We're on the road and we have theorized where it goes and it is your choice to not follow it beyond what you see, both in theory and in (impractical) reality. And that choice has impossible implications, like falling off the edge of the world.

For fednis, to RJ: your purposeful use of improper/denigrating terms like "speculated" is the reason for the continued adversarial tone. If this were a true "agree to disagree situation", you would have come to grips with your choice and left it instead of continuously making false and misleading claims.

And nothing to enable the object to continue to support itself to prevent that collapse. That's a lot of what you are missing/refusing to accept though: it is more that the event horizon passes you than you pass it. You don't have to pass through a zero volume spherical shell, the shell grows to encompass the object as the object collapses.

 

What do you mean? You've seen references where that is plainly/flatly stated. The mathpages reference says all of the stuff I'm telling you that you are choosing to not accept.

 

That is a prediction of GR whether with the collapsar point-like event horizon or the singularity.

I don't see "speculated" as being improper, denigrating or even provocative in any way. I would only think that, perhaps, if it was my position that black holes existed and the word was a challenge to my world view. And the event horizon growing past infalling material is a fine way for you to describe it qualitatively but that simply isn't what the math of GR suggests.

 

We've stretched the analogy too far and you're no longer following it: the impossible predictions I'm referring to are that space ends at the event horizon and objects stop moving or structurally support themselves there.

It is. You know it is. That'said why you used the unscientific word instead of the scientific word.

That's false but as is typical I'm not sure on what level it is false: So please clarify if you think I'm falsely stating the accepted theory or if you are claiming the accepted theory is false.

 

It isn't a physical barrier, it's a temporal one. Mass never stops falling.

The event horizon isn't some physical surface that grows; it's a volume determined mathematically by mass which has been compressed beyond the neutron degeneracy pressure. It can't "grow" to engulf new mass because, by mathematical definition in GR, that new mass has not surpassed that pressure threshold "yet".

 

He's just continuing to claim there is only one choice of coordinates to evaluate the spacetime geometry. He chooses ignorance, his analysis being right, over intellectual honesty. He can't even understand the predictions of his preferred choice of coordinates. That's why I linked Kevin Brown's discussion from his great book 'Reflections on Relativity'. For Fednis and with the hope RJBerry might actually read it. Either he didn't read it or he's incapable of understanding what he read. I have no other choice. Both are probably right. LOL. He claims that GR predicts black holes don't form. He doesn't understand what that means. He should stick with RJBerry predicts black holes don't form since he doesn't have a clue what GR predicts.

 

Bruce, you neglected to comment on your misconception of past light cones and black holes. Was that an oversight, or are you uncomfortable defending your position and unwilling to publicly retract it? Also, as a self-proclaimed authority on GR, what are your qualifications exactly?
From mathpages:

Coordinate switching is not some buoy that you can cling to come hell or high water. The infinite future, as defined by the Schwarzschild coordinates, is a region in spacetime which is required for GR black hole formation. If that region doesn't exist in Schwarzschild coordinates then it will not appear in Kruskal coordinates after the transformation. Neither a closed universe nor an evaporating black hole contain that region.

 

I think RJBeery's response to this is solid. The infinite future in Schwarzschild coordinates may simply not exist; this would be the case if our universe is closed, or if it is a changing 3D universe with a well-defined present, to name two possibilities. If the infinite future does not exist, then going to (e.g.) Kruskal coordinates is basically an improper domain extension. No experiment short of diving into a black hole could tell us the difference, so I still call it a question of interpretation.

Eh, the "just an interpretation" argument cuts both ways. If it's legitimate to stop analysis at the event horizon, then it's also legitimate to continue analysis past it. I think we all agree that collapsars are good descriptions of eternal black holes outside the event horizon, and the "black holes in GR by itself" argument has reduced to a question of how acceptable it is to stop analysis at the event horizon. That's why I'm trying to focus on the case of evaporating black holes; if I understand things properly, they actually don't behave like collapsars, so the event horizons of such black holes should have experimental implications for external observers. I'll keep working on getting the GR experts to check my intuition, but in the mean time, I'll ask you a question. If
the scenario from post #278 -- where infalling mass crosses the event horizon and vanishes at the evaporation point -- were a correct description of GR, would that change your position on black holes?

Thanks for clearing that up.

This seems wrong to me. As I noted before, an observer who goes to the prior location of an evaporated black hole will have in her past light cone a 3D hypersurface that surrounds the black hole in its entirety. Outside of the black hole, the Schwarzschild coordinates are well-defined, and we can talk about a 4D chunk of spacetime events around the black hole. The evaporation of the black hole occurs in finite Schwarzschild time, so any object crossing the event horizon must do the same; unlike with an eternal black hole, we can't push the crossing event off to future infinity. My intuition tells me that the crossing should happen at the evaporation point, but I'm waiting for someone to either agree or disagree with that claim.

I'm not that new here, although my post count is fairly low. I've generally found RJBeery to be one of the more levelheaded and helpful forum members. I agree, though, that this thread's OP was pretty acerbic.

Thanks again for that link. Going back, I noticed the bottom of the chapter linked back to the table of contents, so I'm going to have to read the whole book when I have some time.

 

Good man, Russ.

RJ, forget about coordinates. They're abstract things, they don't exist. Kruskal coordinates especially. They're a total joke, wherein people stick a stopped observer in front of a stopped clock and claim he sees it ticking normally "in his frame". Look instead to what Einstein said, and take it to the limit. We have pretty good evidence that black holes do exist. Whilst we have no evidence whatsoever of any point-singularity, we have evidence of some very massive very small things out there. And do note that the frozen-star black hole is much more of a hole than the point-singularity black hole.

 

I think he's missing the trick. He isn't thinking through the original "frozen star" interpretation, where the black hole grows like a hailstone, from the inside out. It's like you're a water molecule, and you alight upon the surface of the hailstone. You can't pass through the surface, but you get surrounded and buried by other water molecules, so the surface passes through you.

Note that this is the only interpretation which matches Einstein's description of a gravitational field. Einstein described a gravitational field as a place where the speed of light varies. That's it. At the event horizon the "coordinate" speed of light is zero. But Einstein didn't use the word "coordinate". If Einstein was here and you could ask him What's the speed of light at the event horizon? he'd say zero. And then I'd say light can't go slower than stopped.

It is, see above. But see this page from MTW. The improper extension started on the left, in the Schwarzschild chart, wherein the infalling body goes to the end of time and back and is in two places at the same time.

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There's no problem in continuing the analysis. The problem comes when people forget that the motion of light defines your time and distance. When light doesn't move you cannot define a coordinate system. The coordinate system ends at the event horizon, and the interior region is like the gravastar "void in the fabric of space and time".

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IMHO when you look closely at Hawking radiation, it doesn't stand up.

IMHO you should look into Friedwardt Winterberg's firewall.

 

Only just joined and randomly picked your thread for my first post. I havent read the whole thread, I hope you don't mind my comment anyway. About your opening post quoted, do you mean that literally or humorously? If humorously then I will couch my comments accordingly. Same if you meant it seriously. If seriously, I have to ask if that opening comment was because of contempt of others as a starting position for this specific thread, or was it a reactionary position spilling over from contempt shown against you first in other threads? Whatever it was, I hope my responses regarding the black hole and horizon discussion is not taken as support or criticism of any people, only the scientific and logical arguments made regarding the actual topic of the thread. Not having read all your thread (sorry if I missed something important from anyone) my first response to your thread is to ask if anyone has discussed the situation when two equally massive black holes approach so close it distorts respective event horizons just before melding horizons and then merging below the new horizon enveloping both of them (like a dumbell shape?) until the masses become merged completely and have the same common centre of mass, whatever that may be (GR's singularity or QM's extended central mass feature?). If considering only small energy or mass features in falling to one black hole, the arguments get so speculative or esoteric that the physical merger/growth event and process itself, involving both the horizon and the masses, may be missed while arguments turn on the definitions and interpretations of coordinate systems and spacetime which both become a bit unreliable as analytical tools when there is no way to actually confirm or refute their applicability in that case. A more obvious scenario of two equally massive black holes approaching closely and melding and merging might remove some of the more speculative approaches and concentrate the mind and analysis on an event which cannot be denied happens in some way whether as towards singularity or extended feature below horizon at whatever stage in the overall timeline (or is it worldline Im thinking of?) in the universe's continuous activity irrespective of an observer entering the situation at some arbitrary stage in that universe's continuous activity. I hope I havent trespassed on your thread by my comment, RJBeery? I wish your discussion well and will follow even if not commenting again in this discussion.