Black Hole: Why do we believe that matter could be such dense?

[Janus]

22 hours ago, MaximT said:

Is a sum of mass orbiting a Black Hole, could contribute to the gravity force maintaining the rotation in orbit around the center of the galaxy, to make that galaxy objects spin around the center?

Is that sum of mass (all orbiting objects) could reduced the theoretical mass of the Black Hole itself, creating a empty, cannot be seen, zone around it, at the place of dilating it's volume to achieved the same density?

Can objects orbit a common center of gravity?  Yes.   Can this explain or effectively reduce the predicted mass of the central black hole? No.   It's not just the orbital speeds involved, but the shapes of the orbits.  When you look at the plot of the orbits of those stars you will note that since they are very elliptical,  sometimes  a given star will be closer to the center than other stars and sometimes further away.   Any star that is further from the center than you are will not contribute to the force you feel pulling you towards the center.*   By plotting the shape of the orbit as well as its speed at different points, you can calculate just how much of the total mass of the entire system has to be actually be located at the center.  This is what gives you the mass of the BH.

 

* An extreme example of this would be a spherical cloud of stars with a hollow at it center.  For any star in that cloud its orbit is determined by the stars as close or close to the center than it is, the other stars have no effect.  An object that wandered into the central hollow, would be behave as if there were no stars surrounding the hollow at all.

[michel123456]

On 4/13/2019 at 4:46 PM, MigL said:

People are often skeptical of Black Holes because they cannot understand how matter can be compressed to such a high degree in the central singularity ( near zero size ) to reach ( almost ? ) infinite density.

One has to remember that elementary particles, like leptons, are treated as if they have zero size, and only other properties, like the exclusion principle and the statistics they obey, keep an infinity of them from being stacked on top of each other.
As to mass, it is a property of these leptons, not a thing onto itself, and in a Black Hole, this property is conveniently left with the Event Horizon ( along with charge, angular momentum and in a non-classical treatment, entropy ). The EH is the mathematical construct where pre-collapse properties are stored, not the central singularity.

So we have a dimensionless singularity where a large number of dimensionless particles, that no longer have the property of mass, reside.
Is there actually a problem there ?

If the particles have lost the property of mass, where does gravity come from? Doesn't that mean that gravity is something transcendental?

And second question: if space is so much curved in the BH that straight lines become curved, how can we deduce volume & density? Isn't it an error to measure it from our FoR as it is was a ball in regular space?

And 3rd question: from the diagrams as explained in the video I understand that an observer that is inside the BH must have be able to observe events happening outside the BH (since the rays of light are entering the BH) In this case, how can he figure out (measuring) that he is inside a BH or not?

Edited April 15, 2019 by michel123456

[Strange]

42 minutes ago, michel123456 said:

If the particles have lost the property of mass, where does gravity come from?

They have probably lost the property of being particles, as well.

The mass of the black hole, like anything else, is defined by the space-time curvature associated with it.

43 minutes ago, michel123456 said:

And second question: if space is so much curved in the BH that straight lines become curved, how can we deduce volume & density? Isn't it an error to measure it from our FoR as it is was a ball in regular space?

Yes. The volume, and even the radius, of a black hole is not a well defined property. We know the surface area. From that, we can use normal geometry to deduce values we call radius and volume. But they don't mean anything when it comes to the interior of a black hole. For example, what we call the radius is time. 

However, as there are no other words (beyond the mathematics of GR) to describe it, these are still useful analogies.

45 minutes ago, michel123456 said:

And 3rd question: from the diagrams as explained in the video I understand that an observer that is inside the BH must have be able to observe events happening outside the BH (since the rays of light are entering the BH) In this case, how can he figure out (measuring) that he is inside a BH or not?

They can't. If you were to fall into a black hole, the only way you would know you had crossed the event horizon would be if you could do the necessary calculations to know when you would pass it.

[beecee]

1 hour ago, michel123456 said:

If the particles have lost the property of mass, where does gravity come from? Doesn't that mean that gravity is something transcendental?

The gravity is a fossil field from the star whence the BH formed from, so is already there..

Quote

And second question: if space is so much curved in the BH that straight lines become curved, how can we deduce volume & density? Isn't it an error to measure it from our FoR as it is was a ball in regular space?

The volume is deduced from the EH and the density is actually meaningless.

Quote

And 3rd question: from the diagrams as explained in the video I understand that an observer that is inside the BH must have be able to observe events happening outside the BH (since the rays of light are entering the BH) In this case, how can he figure out (measuring) that he is inside a BH or not?

In fact any observer inside the BH, as long as tidal gravitational effects have not torn the observer asunder, would actually probably see the whole universe in the form of a circle above his head, due to lensing. I dare say he would be ripped apart before he had any inkling he had crossed a point of no return.

Edited April 15, 2019 by beecee

[et pet]

2 hours ago, beecee said:

In fact any observer inside the BH, as long as tidal gravitational effects have not torn the observer asunder, would actually probably see the whole universe in the form of a circle above his head, due to lensing. I dare say he would be ripped apart before he had any inkling he had crossed a point of no return.

Fact?

[michel123456]

5 hours ago, Strange said:

They can't. If you were to fall into a black hole, the only way you would know you had crossed the event horizon would be if you could do the necessary calculations to know when you would pass it.

But from this diagram below I understand that the rays of light enter inside the BH.

And in the BH, space is intensely curved, but for any observer living in it I suppose Space is straight, light rays are not curved, and time is different. I suppose that for an internal observer things are just as usual. Why would it be different? With light going at C as for us.

Edited April 15, 2019 by michel123456

[Strange]

13 minutes ago, michel123456 said:

But from this diagram below I understand that the rays of light enter inside the BH.

And in the BH, space is intensely curved, but for any observer living in it I suppose Space is straight, light rays are not curved, and time is different. I suppose that for an internal observer things are just as usual. Why would it be different? With light going at C as for us.

We already live in curved spacetime. The main effect we notice is that thing we call "gravity". With sensitive instruments we can measure some other effects such as gravitational red-shift or lensing.

These effects would all be greater as we approach (and fall into) a black hole: the force of gravity (and tidal forces) would be greater, gravitational red shift would be greater (the rest of the universe would look increasingly blue-shifted), gravitational lensing would be obvious (the event horizon would appear to be 2.6 times larger than expected; the entire accretion disk would be visible, including that on the far-side of the event horizon; our view of the universe would narrow; etc)

 

[Janus]

1 hour ago, michel123456 said:

But from this diagram below I understand that the rays of light enter inside the BH.

And in the BH, space is intensely curved, but for any observer living in it I suppose Space is straight, light rays are not curved, and time is different. I suppose that for an internal observer things are just as usual. Why would it be different? With light going at C as for us.

One of the bizarre things that occurs after crossing the the event horizon is that time and space switch roles.  So describing what you would "see" is a bit difficult. For example, outside of a black hole, if we are looking at a point 1 light hr away, we can only see, at any given moment, events that occurred 1 hr ago. Inside the event horizon, If you are looking at a point further out from the center than you are, at the same 1 light hr away, you would see everything that occurs at that point between 1 hr in the past to 1 hr in the future, all at once.

[Strange]

4 hours ago, Janus said:

One of the bizarre things that occurs after crossing the the event horizon is that time and space switch roles.  So describing what you would "see" is a bit difficult.

Yes, most descriptions gloss over this. For perhaps obvious reasons. It is hard to comprehend how that might appear to our senses and we will probably never know.

[beecee]

9 hours ago, et pet said:

Fact?

Knowledge of GR. https://jila.colorado.edu/~ajsh/

 

7 hours ago, michel123456 said:

But from this diagram below I understand that the rays of light enter inside the BH.

And in the BH, space is intensely curved, but for any observer living in it I suppose Space is straight, light rays are not curved, and time is different. I suppose that for an internal observer things are just as usual. Why would it be different? With light going at C as for us.

The EH is not any physical barrier, but simply a point/circumference in spacetime around the BH, where escape velocity equals and then exceeds "c". As mentioned before, other the tidal gravitational effects [that depend on the size of the BH] we have no indication of crossing anything. 

4 hours ago, Strange said:

Yes, most descriptions gloss over this. For perhaps obvious reasons. It is hard to comprehend how that might appear to our senses and we will probably never know.

 I'll drink to that. 

Edited April 15, 2019 by beecee

[et pet]

5 hours ago, Strange said:

Yes, most descriptions gloss over this. For perhaps obvious reasons. It is hard to comprehend how that might appear to our senses and we will probably never know.

    This seems to conflict with this "fact" that was Posted earlier?

12 hours ago, beecee said:

In fact any observer inside the BH, as long as tidal gravitational effects have not torn the observer asunder, would actually probably see the whole universe in the form of a circle above his head, due to lensing. I dare say he would be ripped apart before he had any inkling he had crossed a point of no return

 

[Strange]

2 minutes ago, et pet said:

    This seems to conflict with this "fact" that was Posted earlier?

I don't think so. We do "know" (based on what GR tells us) how things would look to an observer falling in. We can even run simulations, such as raytracing, to generate images that represent what we see. 

Whether the change of the radial direction from being spatial to being temporal is something we would be aware of or not, is not really known. Simulating what something looks like doesn't tell us anything about how it would feel. 

But it does explain why you still would not be able to see the singularity (or whatever is at the centre of the black hole) even after you pass the event horizon: because it is in your future and, as we all know, you can't see the future!

 

BTW. People often use words like "know" or "fact" to describe our best current understanding based on theory and available evidence. But, as with all science, this knowledge and these facts are, of course, provisional and subject to change with further evidence or new theories.

[beecee]

27 minutes ago, et pet said:

    This seems to conflict with this "fact" that was Posted earlier?

 

You fail to recognise that what I have posted aligns with GR predictions, which obviously we all agree has a pretty good track record. You also fail to see that in my statement I also used the word "probably" thus, "In fact any observer inside the BH, as long as tidal gravitational effects have not torn the observer asunder, would actually "probably" see the whole universe in the form of a circle above his head, due to lensing. I dare say he would be ripped apart before he had any inkling he had crossed a point of no return"

Plus of course the obvious that you seemed to have missed, in that Strange's statement was referring to the time and space changing places, while my statement was in relation to what anyone inside the EH would see outside the EH. And even in that scenario, facts may aspire to prevent you seeing anything outside....[1]Surviving tidal gravity effects, [2] Surviving any infalling matter/energy which would probably be in the form of lethal radiation, [3] and simply surviving longe enough, eg: Even our own SMBH, one would only have around 12 seconds or so, from the trip from the EH to the Singularity.

Couple all that with other contributions of mine and others, that clearly state that "while we certainly can never observe or have direct  evidence of anything about what happens inside a BH, we do have the overwhelmingly supportive and incredibly correct predicitive powers of GR, to at least form a reasonable picture of that which will never be seen.

Hope that helps.

 

Edited April 15, 2019 by beecee

[et pet]

24 minutes ago, beecee said:

You fail to recognise that what I have posted aligns with GR predictions, which obviously we all agree has a pretty good track record. You also fail to see that in my statement I also used the word "probably" thus, "In fact any observer inside the BH, as long as tidal gravitational effects have not torn the observer asunder, would actually "probably" see the whole universe in the form of a circle above his head, due to lensing. I dare say he would be ripped apart before he had any inkling he had crossed a point of no return"

Plus of course the obvious that you seemed to have missed, in that Strange's statement was referring to the time and space changing places, while my statement was in relation to what anyone inside the EH would see outside the EH. And even in that scenario, facts may aspire to prevent you seeing anything outside....[1]Surviving tidal gravity effects, [2] Surviving any infalling matter/energy which would probably be in the form of lethal radiation, [3] and simply surviving longe enough, eg: Even our own SMBH, one would only have around 12 seconds or so, from the trip from the EH to the Singularity.

Couple all that with other contributions of mine and others, that clearly state that "while we certainly can never observe or have direct  evidence of anything about what happens inside a BH, we do have the overwhelmingly supportive and incredibly correct predicitive powers of GR, to at least form a reasonable picture of that which will never be seen.

Hope that helps.

 

    Digging yourself deeper.

   Maybe you should have began your statement : According to Theory, or my interpretation of the Theory of what one might see

   BTW : the Link you provided : https://jila.colorado.edu/~ajsh/insidebh/index.html  , contains this disclaimer " The creation of this website was supported by the National Science Foundation. Statements made herein are those of the author, and do not necessarily reflect the views of the National Science Foundation or of any other entity."

   re, your : "Hope that helps."   , "facts may aspire" means exactly what?

   

   

[beecee]

5 minutes ago, et pet said:

    Digging yourself deeper.

   Maybe you should have began your statement : According to Theory, or my interpretation of the Theory of what one might see

   BTW : the Link you provided : https://jila.colorado.edu/~ajsh/insidebh/index.html  , contains this disclaimer " The creation of this website was supported by the National Science Foundation. Statements made herein are those of the author, and do not necessarily reflect the views of the National Science Foundation or of any other entity."

   re, your : "Hope that helps."   , "facts may aspire" means exactly what?   

   

I'll let you do the digging, OK?  At this time, I'm happy with what I have said and ignore your pedant and ignorance, but if any of our on line professionals object or find fault in what I have said, then I'll humbly listen as always. And "theory"of course is our best estimation as to what is happening and what we see and interpret at any particular time. 

19 minutes ago, et pet said:

    re, your : "Hope that helps."   , "facts may aspire" means exactly what?     

Well looking at the whole context of what I said, and ignoring pedantic nonsense, I believe it entirely comprehensible  "And even in that scenario, facts may aspire to prevent you seeing anything outside....[1]Surviving tidal gravity effects, [2] Surviving any infalling matter/energy which would probably be in the form of lethal radiation, [3] and simply surviving longe enough, eg: Even our own SMBH, one would only have around 12 seconds or so, from the trip from the EH to the Singularity". Self explanatory I suggest.

Edited April 15, 2019 by beecee

[et pet]

54 minutes ago, beecee said:

I'll let you do the digging, OK?  At this time, I'm happy with what I have said and ignore your pedant and ignorance, but if any of our on line professionals object or find fault in what I have said, then I'll humbly listen as always. And "theory"of course is our best estimation as to what is happening and what we see and interpret at any particular time. 

Well looking at the whole context of what I said, and ignoring pedantic nonsense, I believe it entirely comprehensible  "And even in that scenario, facts may aspire to prevent you seeing anything outside....[1]Surviving tidal gravity effects, [2] Surviving any infalling matter/energy which would probably be in the form of lethal radiation, [3] and simply surviving longe enough, eg: Even our own SMBH, one would only have around 12 seconds or so, from the trip from the EH to the Singularity". Self explanatory I suggest.

     ad hominem , much?

       " facts may aspire ", So, are you trying to attribute a human trait, the conscious ability to aspire,  to a fact?

       https://www.merriam-webster.com/dictionary/aspire

    

[MigL]

You seem to have a problem with Beecee and words and phrases he has used ( fact, hope that helps, facts may aspire ), yet you have not posted any meaningful contribution to this topic.
What you are doing is not discussion.
Grow up, before someone decides to report you.

Edited April 15, 2019 by MigL

[beecee]

Getting back to the subject of the thread, as entitled.....The first BH suspect was "Cygnus X1" https://www.nasa.gov/mission_pages/chandra/multimedia/cygnusx1.html                        

"On the left, an optical image from the Digitized Sky Survey shows Cygnus X-1, outlined in a red box. Cygnus X-1 is located near large active regions of star formation in the Milky Way, as seen in this image that spans some 700 light years across. An artist's illustration on the right depicts what astronomers think is happening within the Cygnus X-1 system. Cygnus X-1 is a so-called stellar-mass black hole, a class of black holes that comes from the collapse of a massive star. The black hole pulls material from a massive, blue companion star toward it. This material forms a disk (shown in red and orange) that rotates around the black hole before falling into it or being redirected away from the black hole in the form of powerful jets. 

A trio of papers with data from radio, optical and X-ray telescopes, including NASA's Chandra X-ray Observatory, has revealed new details about the birth of this famous black hole that took place millions of years ago. Using X-ray data from Chandra, the Rossi X-ray Timing Explorer, and the Advanced Satellite for Cosmology and Astrophysics, scientists were able to determine the spin of Cygnus X-1 with unprecedented accuracy, showing that the black hole is spinning at very close to its maximum rate. Its event horizon -- the point of no return for material falling towards a black hole -- is spinning around more than 800 times a second. 

Using optical observations of the companion star and its motion around its unseen companion, the team also made the most precise determination ever for the mass of Cygnus X-1, of 14.8 times the mass of the Sun. It was likely to have been almost this massive at birth, because of lack of time for it to grow appreciably. 

The researchers also announced that they have made the most accurate distance estimate yet of Cygnus X-1 using the National Radio Observatory's Very Long Baseline Array (VLBA). The new distance is about 6,070 light years from Earth. This accurate distance was a crucial ingredient for making the precise mass and spin determinations". 

:::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::

Other such observations have been made. In recent times the discovery of gravitational waves that just happen to match templates as determined by GR, and of course the new image of a BH at m87, or at least the shadow of the BH.

I believe we can be as sure as any scientific theory allows us to be, that BH's are real entities in this big wide wonderful universe we inhabit.

Plenty more info and data in the "First real Black Hole image - 10 April 2019" thread.

 

 

[Q-reeus]

12 hours ago, Strange said:

We already live in curved spacetime. The main effect we notice is that thing we call "gravity". With sensitive instruments we can measure some other effects such as gravitational red-shift or lensing.

These effects would all be greater as we approach (and fall into) a black hole: the force of gravity (and tidal forces) would be greater, gravitational red shift would be greater (the rest of the universe would look increasingly blue-shifted), gravitational lensing would be obvious (the event horizon would appear to be 2.6 times larger than expected; the entire accretion disk would be visible, including that on the far-side of the event horizon; our view of the universe would narrow; etc)

 

That in red is wrong. It's well known that GR predicts the opposite - rest of universe will appear redshifted, not blueshifted. See e.g.:

https://www1.phys.vt.edu/~jhs/faq/blackholes.html#q11

https://www.physicsforums.com/threads/what-do-i-see-while-falling-into-a-black-hole.910174/post-5733039

Some 'authorities' do get it wrong, e.g. here (and reference therein): 
https://physics.stackexchange.com/questions/26185/what-will-the-universe-look-like-for-anyone-falling-into-a-black-hole
 

Edited April 16, 2019 by Q-reeus

[et pet]

1 hour ago, MigL said:

You seem to have a problem with Beecee and words and phrases he has used ( fact, hope that helps, facts may aspire ), yet you have not posted any meaningful contribution to this topic.
What you are doing is not discussion.
Grow up, before someone decides to report you.

   fact :  beecee said:

   "In fact any observer inside the BH, as long as tidal gravitational effects have not torn the observer asunder, would actually probably see the whole universe in the form of a circle above his head, due to lensing. I dare say he would be ripped apart before he had any inkling he had crossed a point of no return."

   I asked if this was fact.

   beecee replied with a Link : https://jila.colorado.edu/~ajsh/ , nothing at that Link corroborated nothing that beecee Posted as fact. Indeed, the Linked site contains this disclaimer " The creation of this website was supported by the National Science Foundation. Statements made herein are those of the author, and do not necessarily reflect the views of the National Science Foundation or of any other entity."

   hope that helps, said beecee.

   How could that Link possibly help?

   facts may aspire ? 

   Yes, MigL, the problem is that what beecee Posted is NOT A FACT!

   It is no more than conjecture, or speculation, or  a subjective interpretation of a somewhat misunderstood understanding of a Theoretical construct.

 From my understanding of the Theory of Relativity, everything inside the Black Hole - including Light - is moving at the very least, at the speed of Light towards some "center". There would be no light or photons that could escape the intense pull of gravity so as to be able to be seen by any eye or receptor.
   What Janus Posted : "One of the bizarre things that occurs after crossing the the event horizon is that time and space switch roles.  So describing what you would "see" is a bit difficult. For example, outside of a black hole, if we are looking at a point 1 light hr away, we can only see, at any given moment, events that occurred 1 hr ago. Inside the event horizon, If you are looking at a point further out from the center than you are, at the same 1 light hr away, you would see everything that occurs at that point between 1 hr in the past to 1 hr in the future, all at once." 

   And also alluded to by Strange : "Yes, most descriptions gloss over this. For perhaps obvious reasons. It is hard to comprehend how that might appear to our senses and we will probably never know."

   Both of these views are much more in line with the current interpretation of Relativity. 

   MigL, there may indeed be students visiting this site to actually learn some science.

   MigL, there is not currently, and most likely never will be any "fact" concerning what one would "see" inside a Black Hole.

   MigL, the only thing close to being attributed as fact would be what Janus, Strange and myself surmise - We Do Not Know And Might Never Know - what one would "see" inside a Black Hole!

[beecee]

4 minutes ago, et pet said:

   MigL, the only thing close to being attributed as fact would be what Janus, Strange and myself surmise - We Do Not Know And Might Never Know - what one would "see" inside a Black Hole!

Fact: While I have always agreed we will never observationally verify anything within a BH's EH, I also stipulate that we can reasonably use GR as a guide. 

Hope that helps.

[beecee]

1 hour ago, et pet said:

   fact :  beecee said:

   "In fact any observer inside the BH, as long as tidal gravitational effects have not torn the observer asunder, would actually probably see the whole universe in the form of a circle above his head, due to lensing. I dare say he would be ripped apart before he had any inkling he had crossed a point of no return."

   I asked if this was fact.

   beecee replied with a Link : https://jila.colorado.edu/~ajsh/ , nothing at that Link corroborated nothing that beecee Posted as fact. Indeed, the Linked site contains this disclaimer " The creation of this website was supported by the National Science Foundation. Statements made herein are those of the author, and do not necessarily reflect the views of the National Science Foundation or of any other entity."

   hope that helps, said beecee.

beecee also said in direct reply to you...

6 hours ago, beecee said:

You fail to recognise that what I have posted aligns with GR predictions, which obviously we all agree has a pretty good track record. You also fail to see that in my statement I also used the word "probably" thus, "In fact any observer inside the BH, as long as tidal gravitational effects have not torn the observer asunder, would actually "probably" see the whole universe in the form of a circle above his head, due to lensing. I dare say he would be ripped apart before he had any inkling he had crossed a point of no return"

Plus of course the obvious that you seemed to have missed, in that Strange's statement was referring to the time and space changing places, while my statement was in relation to what anyone inside the EH would see outside the EH. And even in that scenario, facts may aspire to prevent you seeing anything outside....[1]Surviving tidal gravity effects, [2] Surviving any infalling matter/energy which would probably be in the form of lethal radiation, [3] and simply surviving longe enough, eg: Even our own SMBH, one would only have around 12 seconds or so, from the trip from the EH to the Singularity.

Couple all that with other contributions of mine and others, that clearly state that "while we certainly can never observe or have direct  evidence of anything about what happens inside a BH, we do have the overwhelmingly supportive and incredibly correct predicitive powers of GR, to at least form a reasonable picture of that which will never be seen.

Hope that helps.

 

So one must ask, why do you keep misrepresenting what I said?

Strange also said in direct reply to you......

6 hours ago, Strange said:

I don't think so. We do "know" (based on what GR tells us) how things would look to an observer falling in. We can even run simulations, such as raytracing, to generate images that represent what we see. 

Whether the change of the radial direction from being spatial to being temporal is something we would be aware of or not, is not really known. Simulating what something looks like doesn't tell us anything about how it would feel. 

But it does explain why you still would not be able to see the singularity (or whatever is at the centre of the black hole) even after you pass the event horizon: because it is in your future and, as we all know, you can't see the future!

 

BTW. People often use words like "know" or "fact" to describe our best current understanding based on theory and available evidence. But, as with all science, this knowledge and these facts are, of course, provisional and subject to change with further evidence or new theories.

And obviously, GR is by far our best understanding of BH's considering its incredible predictive powers, so obvious in recent times, so again its reasonable to assume or speculate what is inside. Or do you have a better answer to add to the knowledge and data in this and/or other BH' threads?  

[et pet]

1 hour ago, beecee said:

Fact: While I have always agreed we will never observationally verify anything within a BH's EH, I also stipulate that we can reasonably use GR as a guide. 

Hope that helps.

    So, at the point that GR fails, and even beyond that point, you choose to "stipulate that we can reasonably use GR as a guide" ?

   Is there any possibility that you can explain why you choose to make such a stipulation, or that you may be able to supply any evidence to support such a stipulation?

    

[beecee]

27 minutes ago, et pet said:

    So, at the point that GR fails, and even beyond that point, you choose to "stipulate that we can reasonably use GR as a guide" ?

   Is there any possibility that you can explain why you choose to make such a stipulation, or that you may be able to supply any evidence to support such a stipulation?    

No, I stipulate that GR tells us collapse is compulsory once the EH/Schwarzchild radius is reached. But since it fails at the quantum/Planck level, it is then reasonable to assume that instead of the highly unlikely so called singularity of infinite density and spacetime curvature [which mainstream cosmologists now reject] there probably exists a surface of sorts at or below this quantum/Planck level, which as yet we are unable to really speculate on with any confidence, the likes that GR give us for the rest of the volume that makes up the BH. So any singularity, is simply a singularity defined by the fact that GR and all the other laws of physics fail us there.

Just as I have said many many times before with the confidence of the professionals we do have on this forum

2 hours ago, Q-reeus said:

That in red is wrong. It's well known that GR predicts the opposite - rest of universe will appear redshifted, not blueshifted. See e.g.:

https://www1.phys.vt.edu/~jhs/faq/blackholes.html#q11

https://www.physicsforums.com/threads/what-do-i-see-while-falling-into-a-black-hole.910174/post-5733039

Some 'authorities' do get it wrong, e.g. here (and reference therein): 
https://physics.stackexchange.com/questions/26185/what-will-the-universe-look-like-for-anyone-falling-into-a-black-hole
 

https://jila.colorado.edu/~ajsh/bh/singularity.html#distortion

Image distortion inside the black hole At 0.35 Schwarzschild radii. Compare this view to the unconventional view you would see if the Schwarzschild surface were attached to another Universe via a wormhole. Images are being distorted by two effects: a tidal distortion from the gravity of the black hole, and a special relativistic beaming from our near light speed motion. Just as the tidal distortion redshifts images from above and below, and blueshifts them about your middle, so also it tends to repel images from above and below, and concentrate them about your middle. At first, images appear distorted into a kidney shape. As the distortion grows, images become stretched and squashed into a doughnut shape about your waist. Our near light speed motion concentrates our view ahead, by special relativistic beaming. Relative to observers freely falling radially from rest at infinity, our velocity increases towards the speed of light: the relativistic Lorentz gamma factor at radius rr is 1+2rs/r1+2rs/r.

 

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The distortions grow At 0.01 Schwarzschild radii. The tidal force continues to concentrate our view into a ‘horizon’ shape, while our near light speed motion further concentrates the view ahead. The tidal force and our motion blueshifts photons from the outside world eventually to very high energies, which we would see as x and gamma rays.

Edited April 16, 2019 by beecee

[Q-reeus]

31 minutes ago, beecee said:

 

Quote

 

2 hours ago, Q-reeus said:

That in red is wrong. It's well known that GR predicts the opposite - rest of universe will appear redshifted, not blueshifted. See e.g.:

https://www1.phys.vt.edu/~jhs/faq/blackholes.html#q11

https://www.physicsforums.com/threads/what-do-i-see-while-falling-into-a-black-hole.910174/post-5733039

Some 'authorities' do get it wrong, e.g. here (and reference therein): 
https://physics.stackexchange.com/questions/26185/what-will-the-universe-look-like-for-anyone-falling-into-a-black-hole

 

 

https://jila.colorado.edu/~ajsh/bh/singularity.html#distortion

Image distortion inside the black hole At 0.35 Schwarzschild radii. Compare this view to the unconventional view you would see if the Schwarzschild surface were attached to another Universe via a wormhole. Images are being distorted by two effects: a tidal distortion from the gravity of the black hole, and a special relativistic beaming from our near light speed motion. Just as the tidal distortion redshifts images from above and below, and blueshifts them about your middle, so also it tends to repel images from above and below, and concentrate them about your middle. At first, images appear distorted into a kidney shape. As the distortion grows, images become stretched and squashed into a doughnut shape about your waist. Our near light speed motion concentrates our view ahead, by special relativistic beaming. Relative to observers freely falling radially from rest at infinity, our velocity increases towards the speed of light: the relativistic Lorentz gamma factor at radius rr is 1+2rs/r1+2rs/r.

 

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The distortions grow At 0.01 Schwarzschild radii. The tidal force continues to concentrate our view into a ‘horizon’ shape, while our near light speed motion further concentrates the view ahead. The tidal force and our motion blueshifts photons from the outside world eventually to very high energies, which we would see as x and gamma rays.

It's typical of you to hunt for a contrary finding and just cut & paste it without acknowledging it represents conflicting opinions among assumed GR experts, or explaining your own pov and giving detailed reasoning why. So which of those two conflicting positions do you support, and why exactly? And btw, there is a link from my 2nd linked ref:

https://www.physicsforums.com/threads/black-hole.104577/post-861282

, that gives detailed calculations for (notionally)you, or Strange, to follow. Feel free to 'spot the fatal error'. And note I made it clear in earlier post this is all reasoned on the assumption GR is true hence EH's actually exist. I don't believe in either, but nevertheless expect a better, horizonless theory will share to some degree some of those general tendencies.