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(Big Think)   Yes, there really ought to be a singularity at the center of every black hole   (bigthink.com) divider line
    More: Cool, Neutron star, Black hole, White dwarf, General relativity, Quark, Pauli exclusion principle, composite particles, Fermion  
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839 clicks; posted to STEM » on 30 Nov 2022 at 11:50 AM (9 weeks ago)   |   Favorite    |   share:  Share on Twitter share via Email Share on Facebook



27 Comments     (+0 »)
View Voting Results: Smartest and Funniest
 
2022-11-30 11:38:34 AM  
Welcome to Starshrunks!

Hi, can I get a full black with quantum foam infusion? Served HOT!

Name?

Hawking.

Thanks! Your name will be called in [UNDEFINED] minutes and served with free spaghetti. Plan to stay at the pickup counter until the heat death of the universe. Enjoy your [neverending] day!
 
2022-11-30 12:02:05 PM  
A white dwarf, a neutron star or even a strange quark star are all still made of fermions. The Pauli degeneracy pressure helps hold up the stellar remnant against gravitational collapse, preventing a black hole from forming.

That's my Goodfellas soundtrack cover band.
 
2022-11-30 12:31:53 PM  
That was kind of a rough spackling job over "gravity works with GR till we get to singularities", but overall less objectionable than some of his writing...
 
2022-11-30 12:31:56 PM  
Unless it's rotating, in which case that singularity turns into a goatse hole in the universe.
 
2022-11-30 12:44:13 PM  
Just one singularity, mind you!
 
2022-11-30 12:49:05 PM  
Infinities are a belief system, not science.
 
2022-11-30 12:59:59 PM  
Bugthunk link? BigNope.
 
2022-11-30 1:18:41 PM  

Lambskincoat: A white dwarf, a neutron star or even a strange quark star are all still made of fermions. The Pauli degeneracy pressure helps hold up the stellar remnant against gravitational collapse, preventing a black hole from forming.


My suspicion has been that the Pauli exclusion principle would prevent the ultimate collapse into a singularity, but the object would still be compact enough to form an event horizon.

Ethan seems to be suggesting that this doesn't apply within the event horizon because no interactions can propagate outward from the center, or even propagate anywhere but to the center, if watching all those episodes of PBS Space Time has taught me anything. So if an electron and a proton fall into the black hole, they can't form a hydrogen atom on the way down because they can't exchange force carrying particles. They can't interact. Okay.

So is he saying that the Pauli exclusion principle operates like a fundamental force? I thought it was an inherent feature of spacetime.
 
2022-11-30 1:19:59 PM  

I hereby demand that I be given a Fark account: Just one singularity, mind you!


Do you mean " One singularity sensation..."?
 
2022-11-30 1:47:11 PM  

I hereby demand that I be given a Fark account: Just one singularity, mind you!


What about second singularity? Elevenses?
 
2022-11-30 1:49:48 PM  
It's sort of like a big, weird library where you can spy on your daughter from like 50 years ago and then send her a message on a watch.  Don't get mad at me I don't make the rules.
 
2022-11-30 1:54:06 PM  
You know when idiots think about physics and come up with their own idiot theories just based on the ramblings in their own head, and nothing to do with observations or science... then they go online to tell everone how Einstein was all wrong, and that they alone figured out the truth?

Well, I was thinking about physics this morning and would like to tell the internet how all the scientists have got it wrong: (forgive me, I'm gently off topic because I was thinking about dark matter and not black holes)

So, we have 3 different and incompatible ways we apply physics to problems, astrophysics (gravity is a function of space-time curving) for large scale predictions, Newtonian physics (gravity is an attractive and repellent force) for predictions made at a normal human scale, and quantum physics (gravity is calculated by imagining an exchange of graviton particles) for the itty-bitty scale.

Each field of physics breaks down and doesn't make accurate predictions outside of the size/scale it was designed for. Einstein sucks at figuring out how fast your pinewood derby car will go, or how much weight your table can support.

So what if figuring out why a trillion stars stick together is simply above the size/scale that astrophysics/relativity is good for predicting?

Are we certain that Einstein's understanding of gravity can make predictions that involve hundreds of billions of spread out stars without breaking down in a way similar to how it fails at small scales?

I know I'm an idiot, I was just curious as to what makes my thinks this morning so wrong.
 
2022-11-30 2:43:42 PM  

Captain Shaky: So what if figuring out why a trillion stars stick together is simply above the size/scale that astrophysics/relativity is good for predicting?


If that's the case, then the astrocats will be investigating edge cases, to discover the boundaries of the applicable regimes.

Captain Shaky: Are we certain that Einstein's understanding of gravity can make predictions that involve hundreds of billions of spread out stars without breaking down in a way similar to how it fails at small scales?


Given gravitational lensing, he still seems to be on the right track.
 
2022-11-30 2:57:09 PM  

PartTimeBuddha: Captain Shaky: So what if figuring out why a trillion stars stick together is simply above the size/scale that astrophysics/relativity is good for predicting?

If that's the case, then the astrocats will be investigating edge cases, to discover the boundaries of the applicable regimes.

Captain Shaky: Are we certain that Einstein's understanding of gravity can make predictions that involve hundreds of billions of spread out stars without breaking down in a way similar to how it fails at small scales?

Given gravitational lensing, he still seems to be on the right track.


Thank you for answering me.

And I don't think Einstein has it wrong, his theories have made all sorts of wild, counterintuitive, and specifically weird predictions, which always turn out to be true. Clearly he was right. I just wonder if the ability to apply his theories mathematically breaks down at some upper limit in scale similar to how it breaks down when applying it to small scale predictions (which it does).

No actual Einstein hate. Astrophysics work.
 
2022-11-30 3:15:20 PM  
This is obvious enough that I'm clearly missing something, but wouldn't the effect of gravitational time dilation result in core collapse taking an infinite amount of time to reach a singularity, relative to an external observer? And since black holes evaporate in a finite amount of time relative to an external observer, the singularity would never "actually" form?
 
2022-11-30 3:18:27 PM  

Captain Shaky: No actual Einstein hate.


No problem! Everyone has trouble with singularities. We still can't even guess as to whether physics and math will be able to really get a hold of this one.
 
2022-11-30 4:06:32 PM  
> There must be a singularity at each black hole's center

Isn't this a stupid statement?

the whole black hole is a singularity, not just the point at its center. In fact there all the points in a BH are the same so there are no distinct points within one, particularly not a center.one. A BH is is just an abstract point with measurable  volume.
 
2022-11-30 4:42:48 PM  

HairBolus: > There must be a singularity at each black hole's center

Isn't this a stupid statement?

the whole black hole is a singularity, not just the point at its center. In fact there all the points in a BH are the same so there are no distinct points within one, particularly not a center.one. A BH is is just an abstract point with measurable  volume.


Not true.  The interior of a black hole, meaning the space inside the event horizon, is just an ordinary vacuum (modulo random stuff transiently falling through it).  In a sufficiently large black hole you could in principle survive the tidal forces and move around within the black hole, briefly, until you hit the central singularity.
 
2022-11-30 4:48:59 PM  

CastIronStove: This is obvious enough that I'm clearly missing something, but wouldn't the effect of gravitational time dilation result in core collapse taking an infinite amount of time to reach a singularity, relative to an external observer? And since black holes evaporate in a finite amount of time relative to an external observer, the singularity would never "actually" form?


The black hole forms in finite time, but it appears to collapse more and more slowly before the horizon forms, and you never actually see anything fall into it in finite time - for a non-evaporating black hole.  (There is a finite time at which the last photon from the collapsing star is observed, however.)  For an evaporating hole, you see an infalling object reach the black hole at the same moment it evaporates (even though it passed through the horizon and hit the singularity long ago).
 
2022-11-30 4:50:27 PM  
TFA didn't clearly state that a black hole singularity is inevitable only within classical general relativity (Penrose proved this).  In quantum gravity, all bets are off; no one knows what, if anything, the singularity might be replaced by.
 
2022-11-30 5:59:14 PM  

Ambitwistor: TFA didn't clearly state that a black hole singularity is inevitable only within classical general relativity (Penrose proved this).  In quantum gravity, all bets are off; no one knows what, if anything, the singularity might be replaced by.


Isn't a singularity sort of based on the assumption of a spherical cow though, in regards to angular momentum? They sort of touch on it in TFA but a one dimensional ring singularity? That's too farking weird for me.
 
2022-11-30 6:04:13 PM  

sxacho: Ambitwistor: TFA didn't clearly state that a black hole singularity is inevitable only within classical general relativity (Penrose proved this).  In quantum gravity, all bets are off; no one knows what, if anything, the singularity might be replaced by.

Isn't a singularity sort of based on the assumption of a spherical cow though, in regards to angular momentum? They sort of touch on it in TFA but a one dimensional ring singularity? That's too farking weird for me.


A singularity in gravitational collapse is inevitable in general relativity by the Penrose theorem, but the geometric form of the singularity might be idealized; see the BKL singularity for more complicated theories (this is for cosmology; I can't remember what the situation is for realistic black hole collapse).
 
2022-11-30 8:49:18 PM  

Tranquil Hegemony: Lambskincoat: A white dwarf, a neutron star or even a strange quark star are all still made of fermions. The Pauli degeneracy pressure helps hold up the stellar remnant against gravitational collapse, preventing a black hole from forming.

My suspicion has been that the Pauli exclusion principle would prevent the ultimate collapse into a singularity, but the object would still be compact enough to form an event horizon.

Ethan seems to be suggesting that this doesn't apply within the event horizon because no interactions can propagate outward from the center, or even propagate anywhere but to the center, if watching all those episodes of PBS Space Time has taught me anything. So if an electron and a proton fall into the black hole, they can't form a hydrogen atom on the way down because they can't exchange force carrying particles. They can't interact. Okay.

So is he saying that the Pauli exclusion principle operates like a fundamental force? I thought it was an inherent feature of spacetime.


There was a debate a few years ago when filmmakers were using ray tracing and math to create the (now iconic) black hole from "Interstellar." Apparently there are actually a couple of different models for how that would really work out and the one from Interstellar was chosen purely because it looked really cool. Another, more accurate model rendered the event horizon as an ill-defined region where the background is warped and stretched towards a single, distant point you can never actually see. Thus you never "see" the event horizon, and can't begin to estimate where it actually begins or ends, you just see that the entire universe seems to be rapidly expansing and moving away from you at ever increasing speed except for this one really weird region directly in front of you... And then tidal forces rip you to shreds.

I only saw the test on this once on vimeo. It was ALOT creepier than what they ended up going with, but I can see why they went with the other one with the overly-large black void. Black think "black hole" they want something BLACK, not a giant funhouse mirror with an invisible blender in the middle.

Anyway. Point is, there isn't really anything special about an "event horizon" that implies a small enough neutron star wouldn't also have one. Even if a dense object was still somewhat larger than it's Schwartzchild radius, the distortion of space would be so extreme that you STILL wouldn't really be able to see it; any visible light reflected from it would be scattered as hell and red-shifted WAY down into the radio/microwave spectrum  where there's be nothing there to "see" anyway, just a freakishly strong radio source in the middle of a what appears to a giant spherical lens that has no obvious boundary. More than a few physicists think this is probably what quasars are: massive ultra-dense objects of tens or hundreds of solar masses that, for whatever reason, didn't QUITE collapse below their event horizons but still have enough gravity to compress the entire spectrum into radio waves.
 
2022-12-01 7:03:01 AM  

akallen404: Tranquil Hegemony: Lambskincoat: A white dwarf, a neutron star or even a strange quark star are all still made of fermions. The Pauli degeneracy pressure helps hold up the stellar remnant against gravitational collapse, preventing a black hole from forming.

My suspicion has been that the Pauli exclusion principle would prevent the ultimate collapse into a singularity, but the object would still be compact enough to form an event horizon.

Ethan seems to be suggesting that this doesn't apply within the event horizon because no interactions can propagate outward from the center, or even propagate anywhere but to the center, if watching all those episodes of PBS Space Time has taught me anything. So if an electron and a proton fall into the black hole, they can't form a hydrogen atom on the way down because they can't exchange force carrying particles. They can't interact. Okay.

So is he saying that the Pauli exclusion principle operates like a fundamental force? I thought it was an inherent feature of spacetime.

There was a debate a few years ago when filmmakers were using ray tracing and math to create the (now iconic) black hole from "Interstellar." Apparently there are actually a couple of different models for how that would really work out and the one from Interstellar was chosen purely because it looked really cool. Another, more accurate model rendered the event horizon as an ill-defined region where the background is warped and stretched towards a single, distant point you can never actually see. Thus you never "see" the event horizon, and can't begin to estimate where it actually begins or ends, you just see that the entire universe seems to be rapidly expansing and moving away from you at ever increasing speed except for this one really weird region directly in front of you... And then tidal forces rip you to shreds.

I only saw the test on this once on vimeo. It was ALOT creepier than what they ended up going with, but I can see why they went with the other one with the overly-large black void. Black think "black hole" they want something BLACK, not a giant funhouse mirror with an invisible blender in the middle.

Anyway. Point is, there isn't really anything special about an "event horizon" that implies a small enough neutron star wouldn't also have one. Even if a dense object was still somewhat larger than it's Schwartzchild radius, the distortion of space would be so extreme that you STILL wouldn't really be able to see it; any visible light reflected from it would be scattered as hell and red-shifted WAY down into the radio/microwave spectrum  where there's be nothing there to "see" anyway, just a freakishly strong radio source in the middle of a what appears to a giant spherical lens that has no obvious boundary. More than a few physicists think this is probably what quasars are: massive ultra-dense objects of tens or hundreds of solar masses that, for whatever reason, didn't QUITE collapse below their event horizons but still have enough gravity to compress the entire spectrum into radio waves.


For the movie, you can see the "true" black hole rendering in Fig. 15c of this paper, and what they went with in Fig. 16 (removing redshift and specific intensity changes - giving Fig. 15a - and adding lens flare).

While neutron stars might share optical similarities with black holes, they do not have event horizons. And quasars are not small (10-100 solar mass) compact bodies, but accretion disks of supermassive (millions to billions solar masses) black holes. Their redshift is cosmological in nature (Hubble redshift from the expansion of the universe), not due to gravitational time dilation of the black hole itself; the accretion disk is nowhere near close enough to produce that kind of redshift.
 
2022-12-01 11:10:43 AM  

Ambitwistor: akallen404: Tranquil Hegemony: Lambskincoat: A white dwarf, a neutron star or even a strange quark star are all still made of fermions. The Pauli degeneracy pressure helps hold up the stellar remnant against gravitational collapse, preventing a black hole from forming.

My suspicion has been that the Pauli exclusion principle would prevent the ultimate collapse into a singularity, but the object would still be compact enough to form an event horizon.

Ethan seems to be suggesting that this doesn't apply within the event horizon because no interactions can propagate outward from the center, or even propagate anywhere but to the center, if watching all those episodes of PBS Space Time has taught me anything. So if an electron and a proton fall into the black hole, they can't form a hydrogen atom on the way down because they can't exchange force carrying particles. They can't interact. Okay.

So is he saying that the Pauli exclusion principle operates like a fundamental force? I thought it was an inherent feature of spacetime.

There was a debate a few years ago when filmmakers were using ray tracing and math to create the (now iconic) black hole from "Interstellar." Apparently there are actually a couple of different models for how that would really work out and the one from Interstellar was chosen purely because it looked really cool. Another, more accurate model rendered the event horizon as an ill-defined region where the background is warped and stretched towards a single, distant point you can never actually see. Thus you never "see" the event horizon, and can't begin to estimate where it actually begins or ends, you just see that the entire universe seems to be rapidly expansing and moving away from you at ever increasing speed except for this one really weird region directly in front of you... And then tidal forces rip you to shreds.

I only saw the test on this once on vimeo. It was ALOT creepier than what they ended up going with, but I can see why they went with the other one with the overly-large black void. Black think "black hole" they want something BLACK, not a giant funhouse mirror with an invisible blender in the middle.

Anyway. Point is, there isn't really anything special about an "event horizon" that implies a small enough neutron star wouldn't also have one. Even if a dense object was still somewhat larger than it's Schwartzchild radius, the distortion of space would be so extreme that you STILL wouldn't really be able to see it; any visible light reflected from it would be scattered as hell and red-shifted WAY down into the radio/microwave spectrum  where there's be nothing there to "see" anyway, just a freakishly strong radio source in the middle of a what appears to a giant spherical lens that has no obvious boundary. More than a few physicists think this is probably what quasars are: massive ultra-dense objects of tens or hundreds of solar masses that, for whatever reason, didn't QUITE collapse below their event horizons but still have enough gravity to compress the entire spectrum into radio waves.

For the movie, you can see the "true" black hole rendering in Fig. 15c of this paper, and what they went with in Fig. 16 (removing redshift and specific intensity changes - giving Fig. 15a - and adding lens flare).

While neutron stars might share optical similarities with black holes, they do not have event horizons. And quasars are not small (10-100 solar mass) compact bodies, but accretion disks of supermassive (millions to billions solar masses) black holes. Their redshift is cosmological in nature (Hubble redshift from the expansion of the universe), not due to gravitational time dilation of the black hole itself; the accretion disk is nowhere near close enough to produce that kind of redshift.


Right, but the issue they had was that the event horizon isn't actually THAT BIG compared to the accretion disk, nor does it have a completely sharp edge. A stellar mass black hole would have an EH of just a few km in diameter while the accretion disk would be thousands of kilometers across. If you saw a black region AT ALL, it would be a fuzzy dark point at the center of a swirling disk of hot gas, surrounded by a very very distorted region several times its radius. CG artists always depict that distorted region as being very close to the EH when realistically it would be extremely noticeable at ten times that radius.
 
2022-12-01 3:41:37 PM  
I have been told repeatedly that force-carrying particles are just a mathematical device, and that particles don't literally exchange other particles. This article seems to contradict that
 
2022-12-01 9:13:44 PM  

commanderYOLO: I have been told repeatedly that force-carrying particles are just a mathematical device, and that particles don't literally exchange other particles. This article seems to contradict that


Pretty sure that's true. Wave particle duality appears to suggest that all particles actually ARE waves and what we think of as a "particle" is just the point in space where one wave most strongly interacts with another one.
 
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