Black holes may not exist!

[brucep]

O.K. A Schwarzchild black hole does not exist in reality. It is a non-rotating spherical mass with no magnetic field. Those do not exist. But by idealizing the problem, it makes some aspects of conceptualizing reality a bit easier, than attempting to deal with the gravitational variations introduced by rotation, magnetic fields and an other than spherical mass. It is a good approximation for planets and stars. Less likely as good for real case black holes. But that gets into a whole different discussion.

So to answer your question in a sense the Schwarzchild solution is a simplification of GR, to an idealized form.

About the collapse.., yes that is what the equations say.., but they also begin to return infinities and are generally not considered as a good description of what goes on in reality, inside the event horizon. That subject has for the most part been turned over to theorists working in quantum mechanics, i.e. searching for a viable model of quantum gravity. However, I don't believe that any serious theorist today believes that point singularities are a reality. The word "singularity" seems to be another of those definitions that has different meanings or interpretations depending of who you are talking to.

Predictions made by GR have to a large extent been verified or in some cases proven, but remember as Declan pointed out the event horizon is the limit for GR. Though it still has some problems at galactic and cosmic scales, GR does a good job of describing and predicting the dynamic relationships of gravitationally significant masses, outside the event horizon.

GR does a good job of predicting the path of objects inside the event horizon just by transforming from the Schwarzschild coordinates to Gullstrand–Painlevé coordinates which are good for analyzing the spacetime inside and outside the black hole. Because of the spacelike separation between the outside and inside we can't know anything more about the black hole than it's mass, angular momentum and charge.

From Professor Taylor and Professor Wheeler text Exploring Black Holes.
"we want a metric in the coordinates r, phi, and t_rain. We make this transition in two jumps for events outside the horizon: from bookkeeper coordinates to shell coordinates, then from shell coordinates to rain coordinates. Assume that the resulting metric is valid inside the horizon as well as outside. The transition from bookkeeper coordinates to shell coordinates

dr_shell = dr/(1-2M/r}^1/2 [D]

dt_shell = (1-2M/r)^1/2 dt [C]

Now, to go from shell to rain coordinates use the Lorentz transformation of SR. Choose the rocket coordinates to be those of the rain frame and the laboratory coordinates to be those of the shell frame.

Radial inward direction

dt_rain = - v_rel y dr_shell + y dt_shell [9]

Substitute [C] and [D] into [9]

dt_rain = -[(v_rel y dr) / (1-2M/r)^1/2] + y(1-2M/r)^1/2 dt [10]

Solve for dt

dt = [dt_rain / y(1-2M/r)^1/2] + [v_rel dr / (1-2M/r) [11]

v_rel = (2m/r}^1/2 [12]

y = 1/(1-2M/r)^1/2 [13]

Substitute [12] and 1[13] into [11]

dt = dt_rain - (2M/r)^1/2 dr / (1-2M/r)

Substitute [14] into the Schwarzschild metric and collect terms to obtain the global rain metric in r,phi, and t_rain

This metric can be used anywhere around a non rotating black hole, not just inside the horizon. Our ability to write the metric in a form without infinities at r=2M is an indication that no jerk is felt as the plunger passes through the horizon."

dTau^2 = (1-2M/r)dt_rain^2 - 2(2M/r)^1/2 dt_rain dr -dr^2 - r^2 dphi^2

There are very interesting predictions for the path of objects as they follow the natural path to oblivion.

 

[Aqueous Id]

I guess the remote coordinates are preferred for the group you were talking to. LOL.

Indeed I feel almost powerful when I say they can have their frame and eat it too. Les Misérables!

 

[paddoboy]

indeed i feel almost powerful when i say they can have their frame and eat it too. les misérables!

pml!!

 

[paddoboy]

O.K. A Schwarzchild black hole does not exist in reality. It is a non-rotating spherical mass with no magnetic field. Those do not exist. But by idealizing the problem, it makes some aspects of conceptualizing reality a bit easier, than attempting to deal with the gravitational variations introduced by rotation, magnetic fields and an other than spherical mass. It is a good approximation for planets and stars. Less likely as good for real case black holes. But that gets into a whole different discussion.

Not sure if I totally agree with that.
All BH's start with angular momentum is near certain.
But that in time would be negated, especially when it is active.
I see the Schwarzchild solution as the end product of all BH's....it's the time factor that governs whether they are prevalent now.
And of course any Kerr BH we observe in our FoR, may well already be a simplified Schwarzchild solution from a local FoR.

About the collapse.., yes that is what the equations say.., but they also begin to return infinities and are generally not considered as a good description of what goes on in reality, inside the event horizon. That subject has for the most part been turned over to theorists working in quantum mechanics, i.e. searching for a viable model of quantum gravity. However, I don't believe that any serious theorist today believes that point singularities are a reality. The word "singularity" seems to be another of those definitions that has different meanings or interpretations depending of who you are talking to.

I also don't believe any BH Singularity is infinite in itself, although possibily it may lead to infinite quantities. When that viable QGT model finally comes along, a solid surface of sorts will be shown to exist at that quantum/Planck level I'm sure.

 

[brucep]

Indeed I feel almost powerful when I say they can have their frame and eat it too. Les Misérables!

You have very interesting wit.

 

[Declan Lunny]

The word "singularity" seems to be another of those definitions that has different meanings or interpretations depending of who you are talking to.

Yeppers, that is a true thing ya say there.

In case anyone ever sees ME use the word "singularity" you may go ahead and assume what I'm saying in as few words possible: "where my maths and theory quits working, and return nonsensical results". No more, no less,,,,, that's the original meaning of the term applied to physics, and I love my traditions. (And I am also adverse to "infinities" in physics too. I would pay big money to the person who can send that concept to the Museum of Aether Philosophy.)

 

[Aqueous Id]

Yeppers, that is a true thing ya say there.

In case anyone ever sees ME use the word "singularity" you may go ahead and assume what I'm saying in as few words possible: "where my maths and theory quits working, and return nonsensical results". No more, no less,,,,, that's the original meaning of the term applied to physics, and I love my traditions. (And I am also adverse to "infinities" in physics too. I would pay big money to the person who can send that concept to the Museum of Aether Philosophy.)

It brings to mind that the mathematical singularity at the event horizon is just an apparent infinity of stuff, whereas, like you said of the guy arriving there with a Rolex, things keep on ticking no matter what frame you're in. Then there's the actual physical singularity.

 

[OnlyMe]

GR does a good job of predicting the path of objects inside the event horizon just by transforming from the Schwarzschild coordinates to Gullstrand–Painlevé coordinates which are good for analyzing the spacetime inside and outside the black hole. Because of the spacelike separation between the outside and inside we can't know anything more about the black hole than it's mass, angular momentum and charge.

From Professor Taylor and Professor Wheeler text Exploring Black Holes.
"we want a metric in the coordinates r, phi, and t_rain. We make this transition in two jumps for events outside the horizon: from bookkeeper coordinates to shell coordinates, then from shell coordinates to rain coordinates. Assume that the resulting metric is valid inside the horizon as well as outside. The transition from bookkeeper coordinates to shell coordinates

dr_shell = dr/(1-2M/r}^1/2 [D]

dt_shell = (1-2M/r)^1/2 dt [C]

Now, to go from shell to rain coordinates use the Lorentz transformation of SR. Choose the rocket coordinates to be those of the rain frame and the laboratory coordinates to be those of the shell frame.

Radial inward direction

dt_rain = - v_rel y dr_shell + y dt_shell [9]

Substitute [C] and [D] into [9]

dt_rain = -[(v_rel y dr) / (1-2M/r)^1/2] + y(1-2M/r)^1/2 dt [10]

Solve for dt

dt = [dt_rain / y(1-2M/r)^1/2] + [v_rel dr / (1-2M/r) [11]

v_rel = (2m/r}^1/2 [12]

y = 1/(1-2M/r)^1/2 [13]

Substitute [12] and 1[13] into [11]

dt = dt_rain - (2M/r)^1/2 dr / (1-2M/r)

Substitute [14] into the Schwarzschild metric and collect terms to obtain the global rain metric in r,phi, and t_rain

This metric can be used anywhere around a non rotating black hole, not just inside the horizon. Our ability to write the metric in a form without infinities at r=2M is an indication that no jerk is felt as the plunger passes through the horizon."

dTau^2 = (1-2M/r)dt_rain^2 - 2(2M/r)^1/2 dt_rain dr -dr^2 - r^2 dphi^2

There are very interesting predictions for the path of objects as they follow the natural path to oblivion.

Bruce, the problem here is that you are predicting the dynamics of a region of space or spacetime that cannot be observed. You cannot predict the path inside the event horizon unless you know the real dimensions of the object that lies at its center.., and exactly how far from that surface the event horizon is. And even more important what gravity is not just what it does.

Yes, starting with sufficient assumptions about what might be inside the event horizon, you can predict theoretical paths. But again, the answers to the questions, filled in with assumptions now, lay in the hands of those working in QM and quantum gravity. GR only describes the geometry of the relationships of objects. It does not describe the object itself or why mass interacts with mass as it does.

I don't believe in Farsight's frozen star model, but for the sake of an extreme example, say that it turns out that the physical black hole is only a few meters smaller than the event horizon, any projection of an in falling object's path would be far different than if the physical black hole were only 1% the volume of the event horizon. Simply because the path would end sooner in one case than in the other. And all of that assumes we know what gravity is not just what it does. Go all the way to the extreme and say the physical black hole is just inside the event horizon. In that case there would be no path for any in falling object, inside the event horizon. It would have already impacted the surface.

The point is we don't know what is inside the event horizon or how large it is relative to the event horizon. All we know is how the gravity well of whatever is inside affects objects outside . . , and even that information includes a heavy dose of speculation.

Tell me how big is the black hole at the center of our galaxy? I mean in volume rather than estimated mass. How far inside of its event horizon is it? We can plot the orbits of stars around where it is but do we have any real data that tells us its real volume? Is it a point mass or the size of our solar system? This is information that is not known.

 

[Declan Lunny]

Then there's the actual physical singularity.

Yeppers, that one too. That's the one, if I'm feeling verbose, I define as "A thing we have no physics for a reliable description of,,, and no maths to give sensible numbers to measure it,,,, and no words to tell you what it looks like." When I'm in hurry, I just call it a "singularity".

 

[paddoboy]

The point is we don't know what is inside the event horizon or how large it is relative to the event horizon. All we know is how the gravity well of whatever is inside affects objects outside . . , and even that information includes a heavy dose of speculation.

Again, doesn't GR say that once the Schwarzchild limit is reached, further collapse is compulsory?
[at least to that quantum/Planck region], where no prediction applies or is or can be made.

Tell me how big is the black hole at the center of our galaxy? I mean in volume rather than estimated mass. How far inside of its event horizon is it? We can plot the orbits of stars around where it is but do we have any real data that tells us its real volume? Is it a point mass or the size of our solar system? This is information that is not known.

About the size of our solar system I recall.

 

[brucep]

Bruce, the problem here is that you are predicting the dynamics of a region of space or spacetime that cannot be observed. You cannot predict the path inside the event horizon unless you know the real dimensions of the object that lies at its center.., and exactly how far from that surface the event horizon is. And even more important what gravity is not just what it does.

Yes, starting with sufficient assumptions about what might be inside the event horizon, you can predict theoretical paths. But again, the answers to the questions, filled in with assumptions now, lay in the hands of those working in QM and quantum gravity. GR only describes the geometry of the relationships of objects. It does not describe the object itself or why mass interacts with mass as it does.

I don't believe in Farsight's frozen star model, but for the sake of an extreme example, say that it turns out that the physical black hole is only a few meters smaller than the event horizon, any projection of an in falling object's path would be far different than if the physical black hole were only 1% the volume of the event horizon. Simply because the path would end sooner in one case than in the other. And all of that assumes we know what gravity is not just what it does. Go all the way to the extreme and say the physical black hole is just inside the event horizon. In that case there would be no path for any in falling object, inside the event horizon. It would have already impacted the surface.

The point is we don't know what is inside the event horizon or how large it is relative to the event horizon. All we know is how the gravity well of whatever is inside affects objects outside . . , and even that information includes a heavy dose of speculation.

Tell me how big is the black hole at the center of our galaxy? I mean in volume rather than estimated mass. How far inside of its event horizon is it? We can plot the orbits of stars around where it is but do we have any real data that tells us its real volume? Is it a point mass or the size of our solar system? This is information that is not known.

A problem for you and possibly other folks who don't know how the theory of gravity can be used. As far as GR is concerned it can be used to evaluate strong field physics. The entire path from boundary to the limit r-> 0. Besides the most fun is deriving the physics inside the black hole. BTW proofs are the realm of mathematicians not scientists.

 

[brucep]

Again, doesn't GR say that once the Schwarzchild limit is reached, further collapse is compulsory?
[at least to that quantum/Planck region], where no prediction applies or is or can be made.






About the size of our solar system I recall.

If you can find the figure associated with the Mass of the black hole in units of solar mass. You can factor that by 1477 meter. Then double that for 2M. The Kerr holes event horizon will be between r=M [extremal] and r<2M. For example if the rotation parameter (a, J/M) is .5 [.5c] the horizon will be at r=(3/2)M.

 

[OnlyMe]

Again, doesn't GR say that once the Schwarzchild limit is reached, further collapse is compulsory?
[at least to that quantum/Planck region], where no prediction applies or is or can be made.

Again, the Schwarzschild solution is a simplification of GR and does not represent any real black hole. There is no evidence that any non-rotating spherical black hole with no magnetic field exists anywhere in reality. There is evidence that supports the existence of rotating black holes etc.

And yes there are some mathematical solutions that suggest, based on unproven assumptions about what gravity is or how it works (as opposed to how objects are affected by it), that predicts a total collapse. In the extreme that leads to the mathematical "point" singularity. But there is nothing apart from the math that supports the conclusion.

About the size of our solar system I recall.

Go back to your source and find just how that figure was arrived at. It was not discovered as a function of observation. It is a theoretical extension based on assumptions, which have neither been confirmed or proven.


And Bruce - yes proofs are the realm of mathematics, but that does not interfere with something being proven as a matter of experiment and/or observation.


All too often the line between a discussion of theory and its application to reality, becomes confused with what is known to be reality.

Repeatedly I have tried to point out that this discussion has been trying to address questions and physics which involve aspects of quantum mechanics, from the perspective of GR. GR will never describe the structure of an object, it only describes how that object interacts with other objects as a function of gravity.

Back to your question.., when in the context of GR Schwarzschild black holes are discussed, the discussion is purely theoretical and does not represent anything we know to exist in reality. That does not make the discussion invalid or a waste of time. We very often gain insights about what is real from just such explorations of idealized hypotheticals. But at the same time we cannot assume that every conclusion developed from a idealized hypotheticals, is describing reality.

 

[paddoboy]

Back to your question.., when in the context of GR Schwarzschild black holes are discussed, the discussion is purely theoretical and does not represent anything we know to exist in reality. That does not make the discussion invalid or a waste of time. We very often gain insights about what is real from just such explorations of idealized hypotheticals. But at the same time we cannot assume that every conclusion developed from a idealized hypotheticals, is describing reality.

I havn't much time, so suffice to say I'm not in full agreement of that.
We need something to describe the effects we see.....As of this time, GR BH's are the prime candidate and overwhelmingly most supported.
If it isn't what GR describes, then you tell me what causes the effects we see.
I'm with brucep and others on this entirely.

 

[nimbus]

It is there.
At r=2M. At the event horizon. Light stops, so your light clock stops, so you can't set up a coordinate system.

Why would anyone want to 'set up' a coordinate system on the event horizon? Is that your understanding of what other frames (infaller's frame) do at the EH?

 

[nimbus]

Deleted

 

[Farsight]

But taking it to limit is the point where the observer/clock crosses the event horizon. The event horizon is the limit for general relativity. My reference frame at the event horizon is not the same as your reference frame at some distance observing me. There is no way you can make them into a single preferred reference frame. Galileo first stated and proved this. Einstein expanded upon it to include reference frames experiencing extreme gravity and velocity, no findings have been found to dispute it.

What you're saying here just isn't accurate. See the formation and growth of black holes where Kevin Brown refers to two GR interpretations. See this:

"Incidentally, I should probably qualify my dismissal of the 'frozen star' interpretation, because there's a sense in which it's valid, or at least defensible. Remember that historically the two most common conceptual models for general relativity have been the 'geometric interpretation' (as originally conceived by Einstein) and the 'field interpretation' (patterned after the quantum field theories of the other fundamental interactions). These two views are operationally equivalent outside event horizons, but they tend to lead to different conceptions of the limit of gravitational collapse. According to the field interpretation, a clock runs increasingly slowly as it approaches the event horizon (due to the strength of the field), and the natural 'limit' of this process is that the clock just asymptotically approaches 'full stop' (i.e., running at a rate of zero) as it approaches the horizon. It continues to exist for the rest of time, but it's 'frozen'...

You're indirectly referring to the other interpretation, thinking it's the only interpretation. By the by, this article used to refer to Wheeler, not Einstein. Which is apt, because Einstein would have agreed with the "field" interpretation. He referred to a clock running at a zero rate.

You're saying that general relativity is completely and totally wrong.

No I am not! I champion relativity. I'm saying general relativity is misinterpreted. The wrong interpretation is taken to be the only interpretation.

So what's the theory you have to replace it with? Because you must start where general relativity starts, GR states all reference frames are internally valid.

That it does. But if a clock doesn't tick, there is no reference frame to be equally valid.

You seem to be positing a theory which has a preferred reference frame. There can not exist a single reference frame for all observers, that was the shortfall of Newtonian space and time. General Relativity is internally consistent. It only works by applying the entire theory, once you start separating out parts as good stuff and not good stuff, it fails. There is just no way around that.

You're misunderstanding my position. My position is Einstein's position in that there's a place where the clock rate is zero. The clock doesn't tick there. The clock is stopped. Textbook GR says a stopped observer sees that stopped clock ticking normally. I'm saying he sees nothing. I'm saying the textbooks are wrong, not GR is wrong.

How do you define this "preferred" reference frame you posit? Why is someone in a different reference frame wrong or deceived?

I'm not proposing a preferred frame. What I'm proposing, though I don't see it as something novel or new, is no frame at the event horizon.

 

[Farsight]

... What I was wondering is, if you have any inkling as to Hawking's claim about particle production a quantum distance on the outside of the EH. As you know the EH is the demarcation where the gravitational pull is so strong that even light cannot escape. Hawking theorized that particle pair production occurs on the outside of the EH, and that a 'negative mass' particle falls 'into' the BH (not frozen 'at' the EH), substracting from its mass, and its positive-mass pair equivalent then speeds away from the EH, overcoming the gravitational pull. Have you calculated how much kinetic energy such a particle must have to 'escape to infinity' from that intense gravitational well? To me, it seems impossible that such a particle would have spontaneously acquired a huge kinetic energy, absent an input of energy from some source (such as when we do particle pair production at CERN, etc. via huge energy input).

I concur with your sentiment Walter. Pair production typically concerns electron-positron production, not photon production. Virtual particles are not real particles. If particles are created the energy could come from vacuum energy, then both fall in and the black hole could grow. The are no negative-mass particles. IMHO the given explanation for Hawking Radiation is popscience pseudoscience trash that simply doesn't hold water.

 

[Farsight]

...I would pay big money to the person who can send that concept to the Museum of Aether Philosophy...

You'd better take a look at this, Declan:

Einstein's 1920 Leyden Address

And I quote:

"...Recapitulating, we may say that according to the general theory of relativity space is endowed with physical qualities; in this sense, therefore, there exists an ether..."

Why would anyone want to 'set up' a coordinate system on the event horizon? Is that your understanding of what other frames (infaller's frame) do at the EH?

No. It was just a figure of speech. People typically say define a coordinate system. It's a bit tricky doing that when you're a popsicle.

 

[Declan Lunny]

You'd better take a look at this, Declan:
And I quote:

"...Recapitulating, we may say that according to the general theory of relativity space is endowed with physical qualities; in this sense, therefore, there exists an ether..."

Well then, I stand corrected. There really is an aether. Thank you for disabusing me of my misconception. But you left out my favorite parts of that address. The ..... at the beginning and the ..... at the ending. (Nice try though, since I'm new here you had no way of knowing that I'm not that easy to distract.)