What problems would 'black holes' not being formed solve?

[DrStupid]

No matter what choices you make here and no matter what the time dilation is, when you solve the equations of general relativity (the Oppenheimer-Snyder solution would be a good start - Google for it) for a sufficiently large mass of collapsing matter you'll end up with a singularity.

Is that still the case when Hawking radiation comes into play?

 

[Dale]

I thought Hawking Radiation, Hawking concluded, contained no, or too little, information from inside the event horizon..?

He changed his mind, rather famously and publicly:
https://en.m.wikipedia.org/wiki/Thorne–Hawking–Preskill_bet

 

[Nugatory]

Is that still the case when Hawking radiation comes into play?

Yes. Hawking radiation is a phenomenon associated with the event horizon not the singularity; and it doesn't affect the collapse at all.

 

[DrStupid]

Yes. Hawking radiation is a phenomenon associated with the event horizon not the singularity; and it doesn't affect the collapse at all.

Do you have a corresonding reference?

 

[Nugatory]

Do you have a corresonding reference?

https://projecteuclid.org/download/pdf_1/euclid.cmp/1103899181 and especially the discussion around page 208

 

[DrStupid]

https://projecteuclid.org/download/pdf_1/euclid.cmp/1103899181 and especially the discussion around page 208

It seems I need to go deeper into this document. At the first view I cannot see what it says about the formation of the singularity. It mainly deals with processes near and outside the event horizon during and shortly after its formation.

 

[mathman]

Singularity formation is a result of applying General Relativity without taking into account quantum theory. As I have said before, no one really knows what is happening inside a black hole. Until these two theories are reconciled we just won't know.

 

[Dale]

I don’t think that statements objecting to the formation of the singularity are considered particularly controversial. Singularities also appear in other classical theories and so far have been eliminated by the corresponding quantum theories.

Objections to the formation of the event horizon are certainly more controversial.

 

[sophiecentaur]

depends whether the 'body of science' is an Egyptian pyramid or a space elevator..

Those are both examples of Technology and not 'the body of Science' but the same sort of thing applies. In the times of the Pharos, anyone trying to build a pyramid in a different way from the 'established' way would very likely have run out of time or money - unless there was some significant brilliance on the part of the designer. Plenty of attempts at new technology failed in the past due to \lack of respect' for what was known already.
A space elevator has not yet been built and there may never be a successful one. 'Lack of respect' would be at work if the project was attempted at any time soon.

 

[Zedertie Dessen]

This question amounts to "if the laws of physics did not apply, what would the laws of physics say about <insert nonsense of your choice>?"

Yes, that is pretty much what I thought. I think the OP question can still be valuable in that regard, if only as a kind of recreational thought experiment. For example, in a universe where the speed of light was variable and increased in the area around a collapsing massive object, wouldn't the event horizon radius keep shrinking? Or vice versa. And so on.

And although those scenarios would all be contrary to known facts, I guess one problem (as the OP asked) that might be solved that way - or rather than solved, would not even exist - would be the black hole information paradox, right? But as you suggest with your comment above, if the physics were different to start with then who knows if the lack of the black hole information paradox would have any value.

Finally, perhaps the OP is hinting at past discoveries that started from apparent impossibilities, such as square roots of negative numbers leading to imaginary number math. I have no training in physics so can't even speculate on whether thought experiments regarding a universe where black holes don't form could lead to any discovery comparable to imaginary/complex numbers.

 

[phinds]

I have no training in physics so can't even speculate on whether thought experiments regarding a universe where black holes don't form could lead to any discovery comparable to imaginary/complex numbers.

Well, the problem is that if black holes didn't form then General Relativity would not hold, which would require a HUGE change in the entire way the universe works so it would not be some single change at all and we don't have a clue what it would look like so speculating about it isn't really helpful.

 

[Dale]

would be the black hole information paradox, right?

We already discussed that above, it has already been resolved for some time now. As far as I know there is no current problem which would be resolved.

 

[zonde]

there is nothing to stop the formation of the event horizon. Time dilation is not a local phenomena, so locally a particle falling toward the event horizon just passes through it without even noticing.

This seems to be quite popular argument but it is obviously faulty as it assumes conclusion. So Nugatory's suggestion to google for Oppenheimer-Snyder solution is the right way to go.

Googling for OS solution I found criticism of this solution: Gravitational collapse without black holes. It points toward Penrose for the argument of event horizon formation: "In particular, Penrose (Phys. Rev. Lett. 14:57, 1965) showed that [OS] metric gave rise to trapped surfaces, that is regions of space from which no light rays can escape, and proved that within such surfaces black-hole formation is inevitable."

 

[russ_watters]

This seems to be quite popular argument but it is obviously faulty as it assumes conclusion.

Please be more specific, because I see no assumed conclusion, only a conclusion that logically follows from the starting premises.

Indeed, it looks to me like Nugatory said exactly what I did.

 

[zonde]

Please be more specific, because I see no assumed conclusion, only a conclusion that logically follows from the starting premises.

In first sentence you talk about formation of event horizon, but in second sentence you talk about particle falling towards already formed event horizon.

 

[Dale]

there is nothing to stop the formation of the event horizon. Time dilation is not a local phenomena, so locally a particle falling toward the event horizon just passes through it without even noticing.

This seems to be quite popular argument but it is obviously faulty as it assumes conclusion.

This is not a case of assuming the conclusion, it is a rebuttal of a specific argument. The argument is that there would be infinite time dilation near a horizon. The rebuttal that time dilation is not a local phenomenon is valid.

The argument assumes the horizon and tries to show proof by argumentum ad absurdum that the horizon does not exist. The rebuttal is perfectly entitled to assume the horizon (required in fact) in demonstrating the non-absurdity of the result.

 

[zonde]

it is a rebuttal of a specific argument. The argument is that there would be infinite time dilation near a horizon.

No, that was not the argument. The post to which russ_watters replied was talking about the very center of collapsing body and formation of singularity along with event horizon there.

and if you take a collapsing star, the singularity would form at the centre, right? And the event horizon would expand from there as the star fell into it..

But why would a singularity form at all? As time dilation rose, then the matter compressing in the area would rise, slowing compression. I don't see how time dilation could ever reach infinity at any point, like I said, as matter at the centre compressed, the process would slow down, and prevent infinite time dilation occurring and hence a singularity..

 

[Dale]

No, that was not the argument. The post to which russ_watters replied was talking about the very center of collapsing body and formation of singularity along with event horizon there.

Hmm, I don’t see where you are coming from. The formation of the event horizon is clearly assumed since that is where time dilation becomes infinite.

It is an argumentum ad absurdum. The whole point of argumentum ad absurdum is to assume the thing you wish to disprove. Formation of an event horizon predicts infinite time dilation, infinite time dilation is absurd, therefore the event horizon cannot form. And the rebuttal is that infinite time dilation is not absurd after all.

Edit: perhaps you and I are understanding @DarkStar42’s argument differently, and hence the rebuttal also. In any case the rebuttal is not “obviously” faulty, since with at least one reasonable understanding of the argument it is not faulty at all.

 

[russ_watters]

In first sentence you talk about formation of event horizon, but in second sentence you talk about particle falling towards already formed event horizon.

Ok, going back and reminding myself of the OP and the issue a bit, I see that I changed the scenario slightly from an event horizon never forming to an object falling into an already formed event horizon. I wrote this a while ago, but I believe the reason is that the OP's event horizon never forming scenario is a logically flawed scenario because it describes something that doesn't exist preventing its own formation. Mine avoids the issue of arguing that something that doesn't exist can prevent its own formation. The logic is the same for both (there is actually nothing there to prevent collapse), but mine avoids that contradiction.

[edit2] Note, reducto ad absurdum is a legitimate logical tool, not a fallacy. The OP used the logical tool correctly, but was simply missing a piece of key information about reality that then led to the wrong conclusion. But there's nothing wrong with the approach. It's really just falsification.

[edit3]
And not for nothing, but pretty much nobody ever talks about logical fallicies in scientific contexts. The logic of science is precise; it's derived from [it is] math. This isn't politics, where there are no right answers and arguments can be won on strong rhetoric alone.

 

[zonde]

I wrote this a while ago, but I believe the reason is that the OP's event horizon never forming scenario is a logically flawed scenario because it describes something that doesn't exist preventing its own formation.

You are a bit cryptic so I have to guess that "something" is infinite time dilation. In that case it's not quite the case. OP expressed his doubts that ever increasing finite time dilation prevents configuration from reaching infinite time dilation. So I see no flaw you are talking about.

Note, reducto ad absurdum is a legitimate logical tool, not a fallacy.

Yes, reducto ad absurdum is a legitimate logical tool.
Ok, now I see what you are getting at.
We assume the opposite - that ever increasing finite time dilation does not allow reaching infinite time dilation. In that case particle falling into BH will never cross event horizon which is absurd, right? But your example requires us to believe that BH model is the only possible explanation for super massive astronomical objects we call "Back Holes". Well, it still seems circular reasoning to me.

And not for nothing, but pretty much nobody ever talks about logical fallicies in scientific contexts. The logic of science is precise; it's derived from [it is] math. This isn't politics, where there are no right answers and arguments can be won on strong rhetoric alone.

I'm not sure what do you mean by "logic of science". In any case in science there are no right answers (there are answers that work within some domain of applicability), but certainly there are plenty of answers that are wrong (they contradict observations), inconsistent, ambiguous, untestable. And in science you try to get rid of all these answers.

 

[zonde]

It is an argumentum ad absurdum. The whole point of argumentum ad absurdum is to assume the thing you wish to disprove. Formation of an event horizon predicts infinite time dilation, infinite time dilation is absurd, therefore the event horizon cannot form. And the rebuttal is that infinite time dilation is not absurd after all.

OP does not say or suggest that he considers infinite time dilation as absurd. He said that ever increasing finite time dilation will prevent infinite time dilation occurring.

Edit: perhaps you and I are understanding @DarkStar42’s argument differently, and hence the rebuttal also. In any case the rebuttal is not “obviously” faulty, since with at least one reasonable understanding of the argument it is not faulty at all.

You can not justify faulty argument by constructing a "straw man".

 

[russ_watters]

You are a bit cryptic so I have to guess that "something" is infinite time dilation.

There is nothing cryptic here: this discussion is about the existence or non-existence of the event horizon. The OP assumes its existence in his argument that it can't exist. And there is no logical fallacy in doing so.

Ok, now I see what you are getting at.
We assume the opposite - that ever increasing finite time dilation does not allow reaching infinite time dilation. In that case particle falling into BH will never cross event horizon which is absurd, right?

No. You had it right up to the conclusion. The OP's argument is self-contained and consistent for what it is. In essence, he's describing a divide-by-zero error you get by plugging a "0" into the equation for time dilation at a given distance from the event horizon (vs infinite distance, I believe). Divide by zero is an error, so the event horizon can't form. That's his argument.

But your example requires us to believe that BH model is the only possible explanation for super massive astronomical objects we call "Back Holes". Well, it still seems circular reasoning to me.

No. My argument is a specific rebuttal to the specific claim that a certain math says black holes can't exist/form. It does not go beyond that. There certainly may exist other models that can explain our observations, that haven't been found yet.

I'm not sure what do you mean by "logic of science". In any case in science there are no right answers (there are answers that work within some domain of applicability), but certainly there are plenty of answers that are wrong (they contradict observations), inconsistent, ambiguous, untestable. And in science you try to get rid of all these answers.
[separate post]
You can not justify faulty argument by constructing a "straw man".

Yes, you didn't follow what I mean, and you repeated your faulty approach because of it. What I mean is you should not be looking for rhetorical logic fallacies because they don't apply in science. They're just too hard to actually create. Keep them in the humanities where they belong.

Specifically: Pointing out that while one set of math fails (to allow an event horizon), a different set of math works (to allow an event horizon) is not a logical [strawman] fallacy. As you correctly pointed out: science is about finding the "best" among competing models.

More direct: Please stop citing supposed logical fallacies. Real scientists don't do that when debating each other because they aren't a "thing" in science. You aren't helping yourself with this tactic.

 

[zonde]

There is nothing cryptic here: this discussion is about the existence or non-existence of the event horizon.

Not exactly. Discussion is about formation of event horizon. These are two related but distinct things: existence of event horizon and formation of event horizon.
There is massive object without event horizon. Then some time later there is "massive object" (region of spacetime) with event horizon. The question is what according to model happens in between.

Ok, it does not seem that this is going anywhere. Your are not accepting my criticism and I am not accepting yours. So I will stop here.

 

[DrStupid]

There is nothing cryptic here: this discussion is about the existence or non-existence of the event horizon. The OP assumes its existence in his argument that it can't exist.

I read the the posts of the OP again but didn't find such an argumentation. Can you please quote what you are referring to?

 

[russ_watters]

I read the the posts of the OP again but didn't find such an argumentation. Can you please quote what you are referring to?

My mistake: the Opening/Original Poster introduced the idea in post #27, not in post #1. And there are several minor variations of the issue being discussed.

 

[DrStupid]

My mistake: the Opening/Original Poster introduced the idea in post #27, not in post #1.

I don't even see it in #27. I read it the same way as zonde. The OP does not assume the existence of a singularity. He concludes that it does not exists because it never forms due to an ever increasing but finit time delation. This argumentation is at least valid for an external observer. And I expect it to be even valid for an observer in the center when Hawking radiation comes into play.

 

[russ_watters]

I don't even see it in #27. I read it the same way as zonde. The OP does not assume the existence of a singularity. He concludes that it does not exists because it never forms due to an ever increasing but finit time delation.

I'm not seeing a difference. You can call it "ever increasing but finite", but it "approaches infinity" and the existence of the asymptote is one of the features of that math. It's like saying for y=1/x as x approaches 0, y "approaches infinity" but remains finite. Even if you don't state the existence of the asymptote it is still there, as a feature of the math used in the argument.

And I don't understand why you and apparently zobd think this is an issue: we're not claiming the description is mathematically wrong, however you want to word it!

[edit] Btw, maybe what you really should want to know is why, if the scenarios are similar, did I introduce a slight alteration? I did it because it is cleaner. The changes in the arrangement of matter and simultaneous changes in the shape of the gravitational field are complex and I doubt have even been well modeled. So I think it is easier to visualize a static gravitational field and an object dropping into it. It's the same logic/question applied to a simplified problem.

[edit2] Acually, I would think the moment of creation requires quantum mechanics and general relativity: you'd have to describe something like the gravitational field around two neutrons that collapse into each other and form a tiny black hole. After that, everything else is the scenario I describe(with the addition of a non negligible growth rate).

 

[DrStupid]

It's like saying for y=1/x as x approaches 0, y "approaches infinity" but remains finite.

Exactly. And that's something completely different than y=1/x with x=0. Or do you really think that there is no difference between x=0 and x<>0?

 

[russ_watters]

Exactly. And that's something completely different than y=1/x with x=0. Or do you really think that there is no difference between x=0 and x<>0?

I'm saying that the equation describes both, whether someone mentions both or not. And again I ask: why are we splitting this hair?

 

[DrStupid]

And again I ask: why are we splitting this hair?

Because that's the topic. The argumentation of the OP means in your analogy above, that x will never reach the singularity x=0.

 

[russ_watters]

Because that's the topic. The argumentation of the OP means in your analogy above, that x will never reach the singularity x=0.

That's not an answer to my question. I'm asking what relevant difference there is that makes one description useful and the other not.

It's like we're discussing the speed of a pink racecar and you are arguing that it is salmon, not pink. So what? What does that have to do with the issue being discussed?

 

[Dale]

OP does not say or suggest that he considers infinite time dilation as absurd. He said that ever increasing finite time dilation

That is infinite. Infinite means that if you pick any finite number, it gets bigger.

You can not justify faulty argument by constructing a "straw man".

I don’t think that I am. I think that you are misunderstanding the OP’s argument.

 

[Dale]

These are two related but distinct things: existence of event horizon and formation of event horizon.

But the specific “absurdum” argued applies equally to both. The argued “absurdum” is infinite time dilation which occurs just outside the event horizon regardless of whether you are talking about Schwarzschild or OS.

 

[zonde]

But the specific “absurdum” argued applies equally to both. The argued “absurdum” is infinite time dilation which occurs just outside the event horizon regardless of whether you are talking about Schwarzschild or OS.

In Schwarzschild solution infinite time dilation occurs at finite proper time of infalling particle. It is not obvious that by analogy adopting proper time of particle at the center of collapsing body would be a good strategy in case of OS solution. Say distant observer is observing two different massive bodies shortly before gravitational collapse that have different gravitational time dilation at the center of the body. There is no reason to prefer time at the center of one body over the time at the center of the other body. But if we would try to adopt coordinate chart where each center of the body runs at it's own proper time we would accumulate time difference over time (for static bodies). So the obvious choice for distant observer is to keep his own time for coordinate chart. But in that chart infinite time dilation for collapsing body would be reached at infinite future of this coordinate chart or in plain English - never.
Alternatively you could try to adopt simultaneity that depends on dynamics of collapsing body. But this is highly non-trivial and besides it might lead to break point in simultaneity planes at the center of the body. If you try to avoid that it becomes even less trivial.

So the point is that analogy between Schwarzschild and OS regarding infinite time dilation is far from obvious.

 

[zonde]

I would like to add that from my previous post it seems that conclusion about physical situation might depend on the size of adopted coordinate chart. This situation is known by more than 2000 years from the time when Zeno came up with Achilles and the tortoise paradox. However philosophers have not reached consensus how the paradox should be solved.
My position is that the right resolution to the paradox is given by Diogenes i.e. (the reasoning of Zeno is sound but) it contradicts observations. It is sort of the thing that in science is taken as obvious: not every correct mathematical model describes reality and therefore we have to test our models against observations.