There IS no interior of a black hole

[C C]

Revision of prior post (to Mike Fontenot):

Due to some kind of geographical location discrimination(?), that RSP page immediately went blank and dysfunctional for me (was confined to only brief glimpses of it). But using a proxy I can finally see that even the abstract contains the quote. So nix the "access" issue (below) being an impediment to such, if it displays fully for you and others. Mistakenly assumed the quoted part surely wouldn't be in an abstract. (Only three pages, apparently a transcribed speech or lecture of Dirac's with appended discussion, rather than the original situation consisting of a submitted paper.)

What did you mean in your last sentence above? In particular, what did you mean by "mediated" in that sentence?

Mitra's paper is just a secondary source of the Dirac quote, for anyone who is either membership or paywall blocked at RSP (i.e., those who need an accessible reference).

But here the first page is available without hassle: https://www.jstor.org/stable/2414537

Wasn't aware of the above at the time, or I would have used it instead.

 

[Mike_Fontenot]

Mitra's paper is just a secondary source of the Dirac quote, for anyone who is either membership or paywall blocked at RSP (i.e., those who need an accessible reference).

But here the first page is available without hassle: https://www.jstor.org/stable/2414537

Wasn't aware of the above at the time, or I would have used it instead.

_

I didn't have any trouble reading Dirac's quote. The important part of that quote was

"I feel that the space inside the Schwarzschild radius must belong to a different universe and should not be taken into account in any physical theory."

My question to you (C C), though, concerned the sentence:

"Note that the specific quote above from it was mediated through Abhas Mitra's "Mass of Schwarzschild Black Holes Is Indeed Zero And Black Hole Candidates Are Quasi Black Holes".

My question to you is, what did you mean by "mediated" in that sentence?

 

[foghorn]

I didn't have any trouble reading Dirac's quote. The important part of that quote was

"I feel that the space inside the Schwarzschild radius must belong to a different universe and should not be taken into account in any physical theory."

Dirac acknowledges material can cross the event horizon, my bold below in quote '' to sent a signal inside''
Dirac:

The mathematicians can go beyond this Schwarzschild radius, and get inside, but I would maintain that this inside region is not physical space, because to send a signal inside and get it out again would take an infinite time,

Dirac:

the space inside the Schwarzschild radius must belong to a different universe and should not be taken into account in any physical theory.

My bold above.
A '' physical theory'' says a black hole increases in size and mass due to infalling material.
Is Dirac saying we can't use that ''physical theory'' inside the event horizon, and will that mean the black hole decreases in size and mass and so have less gravitational influence on its surroundings once material crosses the event horizon?

Both Dirac quotes from:
https://royalsocietypublishing.org/doi/10.1098/rspa.1962.0228

 

[Mike_Fontenot]

Dirac acknowledges material can cross the event horizon, my bold below in quote '' to sent a signal inside''

My reading of Dirac's words says that the event horizon can't be "crossed", because there is NOTHING inside the event horizon. The event horizon is a surface, and that surface is the ENTIRE black hole.

The most important thing that Dirac said is:

"the space inside the Schwarzschild radius must belong to a different universe and should not be taken into account in any physical theory."

That "different universe", if it exists anywhere at all, doesn't exist in our universe, and doesn't interact in any way with our universe.

A '' physical theory'' says a black hole increases in size and mass due to infalling material.
Is Dirac saying we can't use that ''physical theory'' inside the event horizon, and will that mean the black hole decreases in size and mass and so have less gravitational influence on its surroundings once material crosses the event horizon?

I don't think Dirac was saying anything about a black hole decreasing in size. I think a black hole will grow, as incoming attracted masses hit (and adhere to) the event horizon.

 

[Ethernos D Grace]

One of the "made my day" moments in my life was when I had been studying Schwarzchild's GR solution for a spherical non-rotating massive object. He gets a quadratic equation, and its two solutions are almost universally interpreted as being the exterior and interior of a black hole. But I didn't (and don't) think that was right: I thought that (as often happens in physics) only one of the two quadratic solutions applied to the problem at hand, and the other was just a spurious mathematical result with no physical significance. So with my interpretation, there IS nothing beyond the event horizon. I expressed that view on a moderated usenet group ("foundations", which no longer exists), and said that I realized I was in the tiny minority in that view. The moderator told me I was in good company, though ... Dirac had published a paper in the mid 60's concluding the same thing. The moderator gave me an on-line link to his paper, and I read it, and confirmed that our views were the same. If Dirac ever changed his mind, I'm not aware of it.

I can only answer in layman terms as my knowledge is not high on physics.
Actually there is an interior of blackhole but that space is separated by event horizon.the time inside blackhole is not moving at the same rate as beyond event horizon. that's it.

 

[Ethernos D Grace]

I can't understand how that can work, since it seems to rely on matter already accumulated on this surface. But immediately after the black hole forms, there is no matter there. So what stops the first piece of matter to arrive? It can't be other matter, as there isn't any, yet. As Dave says, the only force acting is the gravitation from the singularity at the centre. So the matter will be accelerated in, surely?

Let me try to explain this,uhmm...
Since the time moving inside is at halt. I.e. once the particle crosses the event horizon there is no time, in sense of physics, the particle stops it's movement completely. Rest i will answer after comprehending it...wow! I'm impressed by myself..i use to think I knew no physics but it turns out i have almost the complete comprehension in layman's term.now all i need to do is solve the Hawking radiation related to it. Check out my post and tell me how it works.

 

[James R]

I didn't have any trouble reading Dirac's quote. The important part of that quote was

"I feel that the space inside the Schwarzschild radius must belong to a different universe and should not be taken into account in any physical theory."

Without further context, I would interpret this to be referring to the fact that no information comes out of a black hole. But when was this written? Prior to the discovery of Hawking radiation?

I think that Dirac meant that whatever might be inside the event horizon, it can have no effect on the outside universe, so there's no need to take it into account in determining anything that's happening in the outside universe.

I doubt that he actually meant there's a whole separate universe inside a black hole.

 

[Mike_Fontenot]

(Here is Dirac's statement): "I feel that the space inside the Schwarzschild radius must belong to a different universe and should not be taken into account in any physical theory."

"Without further context, I would interpret this to be referring to the fact that no information comes out of a black hole."

I think it says MUCH more than that.
I think by "different universe", Dirac was literally saying that the equation for r < 1 describes another universe that has absolutely nothing to do with our universe ... it doesn't "co-exist" with our universe ... if it exists at all, it is an alternative universe, unconnected in any way with our universe. So no mass ever goes from outside the event horizon to inside the event horizon (because there IS no inside the event horizon).

I think that Dirac meant that whatever might be inside the event horizon, it can have no effect on the outside universe, so there's no need to take it into account in determining anything that's happening in the outside universe.

I believe that Dirac believed that NOTHING was inside the event horizon. Or, stated more precisely, that there IS no inside of the event horizon.

I doubt that he actually meant there's a whole separate universe inside a black hole.

We agree about that.

 

[exchemist]

(Here is Dirac's statement): "I feel that the space inside the Schwarzschild radius must belong to a different universe and should not be taken into account in any physical theory."



I think it says MUCH more than that.
I think by "different universe", Dirac was literally saying that the equation for r < 1 describes another universe that has absolutely nothing to do with our universe ... it doesn't "co-exist" with our universe ... if it exists at all, it is an alternative universe, unconnected in any way with our universe. So no mass ever goes from outside the event horizon to inside the event horizon (because there IS no inside the event horizon).



I believe that Dirac believed that NOTHING was inside the event horizon. Or, stated more precisely, that there IS no inside of the event horizon.



We agree about that.

That’s obviously an extrapolation that is not remotely justified by what Dirac said. He even speaks about there being space inside the radius. So to deny there is an inside is directly contradicting Dirac.

 

[Mike_Fontenot]

That’s obviously an extrapolation that is not remotely justified by what Dirac said. He even speaks about there being space inside the radius. So to deny there is an inside is directly contradicting Dirac.

Can you give me that quote from Dirac?

 

[billvon]

But I THINK his and my conclusion at that time was that, not only is there no MASS inside of the event horizon, there is no space or time in there either.

Gravitational force can be measured, and we can get proxy measurements of that gravitational force by (for example) measuring the energy of photons coming from material falling in to a black hole.

For there to be gravitational force, there has to be mass.

 

[exchemist]

Can you give me that quote from Dirac?

The quote is in post 29. He says ".....I feel that the space inside the Schwarzschild radius must belong to a different universe and should not be taken into account in any physical theory..."

So he seems to says there is space but not space to be included in any physical theory.

What I still can't work out, though, is how he thinks the mass of a black hole (a concept that did not exist in his day) exerts its gravitational influence, if the space inside is discarded from any physical theory.

 

[Mike_Fontenot]

For there to be gravitational force, there has to be mass.

That mass is the event horizon itself. There is nothing inside the event horizon. There IS no "inside the event horizon".

 

[Mike_Fontenot]

The quote is in post 29. He says ".....I feel that the space inside the Schwarzschild radius must belong to a different universe and should not be taken into account in any physical theory..."

So he seems to say there is space but not space to be included in any physical theory.

I think when he says "I feel that the space inside the Schwarzschild radius must belong to a different universe", he is saying that that space doesn't exist at all in our universe ... it is (at most) a space (or spacetime) in a different universe that has no connection or relevance to our universe.

What I still can't work out, though, is how he thinks the mass of a black hole (a concept that did not exist in his day) exerts its gravitational influence, if the space inside is discarded from any physical theory.

[/quote]

The mass of the black hole is located at the event horizon, nowhere else.

 

[billvon]

That mass is the event horizon itself. There is nothing inside the event horizon. There IS no "inside the event horizon".

The event horizon is a planar surface with zero thickness. A zero thickness surface has no mass; it is an abstraction.

If you say that "the thing inside the volume defined by the event horizon has mass" then that makes sense. But saying the event horizon has mass is like saying the midpoint between the Earth and Moon has mass.

 

[exchemist]

I think when he says "I feel that the space inside the Schwarzschild radius must belong to a different universe", he is saying that that space doesn't exist at all in our universe ... it is (at most) a space (or spacetime) in a different universe that has no connection or relevance to our universe.





The mass of the black hole is located at the event horizon, nowhere else.

We know you think that, but we think that must be ballocks. You have yet to explain what force magically stops an in-falling mass at the event horizon and you have yet to explain why we can't see any accretion of matter at the event horizon.

 

[Mike_Fontenot]

The event horizon is a planar surface with zero thickness. A zero thickness surface has no mass; it is an abstraction.

Actually, the event horizon is a SPHERICAL surface.

Granted, a surface is a two-dimensional object that has no volume. So how does the event horizon, which Schwarzchild's equations say is a surface, have any mass?

I don't know the answer to that question. Perhaps, the answer is that, calling the event horizon a surface is an abstraction ... an approximation of an actual spherical boundary that has a finite, but very small, thickness. And perhaps, as arriving masses continue to "splat" onto that event horizon, the very small thickness of the event horizon gets very slightly thicker, or maybe just bigger ... i.e., perhaps the radius of the event horizon gets slightly larger, with no increase in thickness.

If you say that "the thing inside the volume defined by the event horizon has mass" then that makes sense.

It may make sense to you (and many others), but it's not what I (and I think Dirac also) believe the "inner" Schwarzchild equation means ... we think it refers to another universe that has nothing at all to do with our universe, and which is completely separate from our universe (i.e., not a part of our universe), with no interaction at all between our universe and the alternate universe (if it exists at all ... that second equation might just be "spurious"). That rules out the possibility that a person could approach the event horizon (starting from earth), and pass through it, and proceed into a volume inside the event horizon.

As best I recall (but my memory is fuzzy), that second equation is VERY strange ... it says (I think) that an object falling into the interior of the black hole will end up somewhere on an infinitely long line (not at a point), and it takes an infinite time to get there. (Or maybe that situation is what the new revised equations, which give the perspective of a traveler entering the blackhole, say.)

 

[Mike_Fontenot]

[...]
You have yet to explain what force magically stops an in-falling mass at the event horizon
[...]

It splats onto the event horizon (which is VERY massive).

... and you have yet to explain why we can't see any accretion of matter at the event horizon.

Because the HUGE mass of the event horizon prevents any light from returning to the earth from there. There ARE ways we can estimate the mass of the black hole (e.g., by observing the parameters of something orbiting the (invisible) black hole.

 

[billvon]

It splats onto the event horizon (which is very massive.)

This is a common misconception. To an observer falling towards the black hole, he notices no impact or discontinuity when he crosses the event horizon. He does notice the increasing tidal forces of course, which by that time are stretching him into a very long line of atoms.

To someone OUTSIDE the event horizon, they see him redshifting more and more as he approaches the horizon. They never actually see him pass it, since that light cannot reach them.

 

[foghorn]

It splats onto the event horizon (which is VERY massive).

That's not what Dirac says, see below.
Mike, I have found Dirac's 1975 book ''General Theory of Relativity''.
Here is a page from that book:


https://books.google.co.uk/books?id=7V2YDwAAQBAJ&source=gbs_book_other_versions

* * * * *

r = radius

2m is the Schwarzschild radius.( look-up mass in units of length. It makes things simpler, so they say).

I have underlined where Dirac says things may fall into it.

You may know that r< 2m means radius smaller than Schwarzschild radius.