<p>One often speaks of a singularity in the context of black holes as the Einsteinian field equations show a singularity for those cases where there is no known force any longer to counter the gravity of the enclosed mass.</p>
<p>However that a suggested or alleged resulting singularity in spacetime might even very likely be not the truth, but is all we can safely assume with our current knowlege of gravity.</p>
<p>However, General Relativity does not account for quantum effects - yet those definitely DO play a role at microscopic scales. A singularity by definition is microscopic. As such: no-one knows what kind of physic laws we see <em>within the centre</em> of a black hole. Maybe we can get a step further if someone comes up with a good theory of quantum gravitation - but I'm not aware of any successful attempts yet.</p>

CC BY-SA 4.0
2024-06-07T18:23:24.633Z
2024-06-07T18:23:24.633Z
planetmaker
<p>A singularity is what the equations predict is at the center, however a point both infinitely small and infinitely dense breaks down the known laws of physics and our current understanding of physics cannot tell us exactly what occurs around that point. A torus or even a sphere/disc shaped singularity could not exist, as currently our understanding is that a singularity must either be 2 or zero dimensional. A point singularity seems to be what is most often described, however it would only form from an non-rotating star, which have never been observed. Its thought that since every star observed so far rotates, every black hole would be a <a href="https://en.m.wikipedia.org/wiki/Rotating_black_hole" rel="nofollow noreferrer">Rotating black hole</a>, with a <a href="https://en.m.wikipedia.org/wiki/Ring_singularity" rel="nofollow noreferrer">ring singularity</a> which is two dimensional. The event horizons of rotating black holes can indeed flatten out to a degree and have non-spherical event horizons as well. Also <a href="https://en.m.wikipedia.org/wiki/Planck_star" rel="nofollow noreferrer">planck stars</a> is another possibility on what may exist as apposed to a singularity.</p>

CC BY-SA 4.0
2024-06-18T03:00:33.717Z
Welcome to our site, and congrats on your first answer. It's important to understand that the purpose of a Stack Exchange site is to provide *authoritative* answers, preferably supported by evidence. This is particularly relevant for science-based SE sites like ours. Answers based on "my understanding" or what "I believe" are more likely to be *opinion*, which is discouraged on SE sites; in fact, a question inviting opinions will usually be closed as quickly as possible.
Chappo Hasn't Forgotten
CC BY-SA 4.0
2024-06-18T03:05:58.350Z
"a point both infinitely small and infinitely dense is not possible" – and yet, the mathematics of black holes produces just such infinities. Channeling Galileo: "*Eppur si muove.*"
Chappo Hasn't Forgotten
CC BY-SA 4.0
2024-06-21T04:20:40.920Z
@ChappoHasn'tForgotten sure thing :)
ArchiveOfStars
CC BY-SA 4.0
2024-06-25T09:58:38.953Z
@Chappo
I dont know the final answer of this
Peter
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2024-06-25T10:08:12.160Z
@ChappoHasn'tForgotten
I dont know the final answer, but if you don't start with perfect spheres, donuts could form, ring singularities, and rings surfaces 2 dimensional, which makes a bit sense. I think, blackhole emissions (hawking radiation) seem to point to a certain shape as well, as it doesn't point into random directions.
Well I think the final answer is that some people do think about such, and others thinking in the larger scales find it ideal to speak of as a point.
Peter
CC BY-SA 4.0
2024-06-15T18:55:25.290Z
2024-06-28T21:29:27.370Z
2024-06-28T21:29:27.370Z
ArchiveOfStars
<p>I'm not a physician nor an astronomer, I am just curious.</p>
<ul>
<li>When I think that a star collapses, and think of large bodies that rotate.<br />
Then it's likely that the sphere is not a perfect sphere.<br />
Most likely the poles are closer to each other.</li>
<li>And usually, things that spin rotate faster if they get smaller (try it on an office chair).</li>
</ul>
<p>Combining the above let me conclude that it's way more likely to endup with a donut.<br />
Or if the spin is extremely high, perhaps other torus shapes (spirograph alike).</p>
<p>So to me, a singularity-<strong>point</strong> seems highly unlikely.<br />
a circle, donut or thorus seems more likely, why is it that people often speak of a point?.Why isn't it a mainstream thought ?.</p>
<p>I hope it's okay to ask.</p>

CC BY-SA 4.0
2024-06-06T17:40:19.683Z
Spinning black holes don't have point singularities, they have ring singularities. And we generally expect real black holes to spin. See https://astronomy.stackexchange.com/a/20292/16685 OTOH, we aren't *certain* that singularities are physically real. Hopefully, a quantum gravity theory will resolve that issue. Also see my answer https://astronomy.stackexchange.com/a/49960/16685
PM 2Ring
CC BY-SA 4.0
2024-06-06T21:54:40.083Z
Ultimately, a singularity is a mathematical construct for a part of the universe that we don't really understand. The inside of a black hole probably operates under rules we just don't know about, and whether the big divide-by-zero error is shaped like a point or a ring is not particularly important outside of some extremely arcane corners of science. "A black hole has a singularity in the middle where physics doesn't work" is good enough for anyone who isn't diving pretty deep into a complicated topic.
Darth Pseudonym
CC BY-SA 4.0
2024-06-06T22:27:25.243Z
@PM2Ring We don’t really know what the nature of the singularity in a typical rotating BH. The ring singularities present in eternal Kerr are likely not representative of the general case.
TimRias
CC BY-SA 4.0
2024-06-06T23:11:18.423Z
@TimRias Fair point. On that note... https://physics.stackexchange.com/q/790724/123208
PM 2Ring
CC BY-SA 4.0
2024-06-07T07:10:05.133Z
I don't see any literature on this, even in mainstream, talking of a point, so your question "why isn't it a mainstream thought" is misguided.
Rory Alsop
CC BY-SA 4.0
2024-06-07T11:36:50.447Z
Well misguided by people speaking of a singularity point, mainly youtube science festival
Peter
CC BY-SA 4.0
2024-06-07T13:19:33.677Z
@Peter I'm not sure what you're referring to exactly, but YT science videos are usually intended for a general audience, or at least science-savvy non-experts, so they probably aren't going to go into a lot of detail about stuff like how a singularity is actually shaped (and again, I reiterate, we *do not know* if singularities are actually a real thing, let alone how they would be shaped).
Darth Pseudonym
CC BY-SA 4.0
2024-06-15T19:41:26.783Z
A key thing to remember is that the singularity is not an object in spacetime, or the remnant of the collapsed star.  It is a feature of the solution of the equations, an "infinity" that appears at certain **spacetime** coordinates.  It is not an object at all.  It is a "where-and-when".  More confusingly the "when" is always "later".  You can never visit the singularity because there is no spacetime after the singularity.  Try hard not to think if the singularity as being a stellar remnant, it really isn't.
James K
CC BY-SA 4.0
2024-06-20T08:15:36.220Z
https://en.wikipedia.org/wiki/Physician Not to be confused with physicist.
PM 2Ring
<black-hole>
why would a black hole have a singularity point ? (a ring or disk seams more likely to me)
Peter
# why would a black hole have a singularity point ? (a ring or disk seams more likely to me)

(Asked by: username_0 on 2024-06-06)

I'm not a physician nor an astronomer, I am just curious.

* When I think that a star collapses, and think of large bodies that rotate.  
  Then it's likely that the sphere is not a perfect sphere.  
  Most likely the poles are closer to each other.
* And usually, things that spin rotate faster if they get smaller (try it on an office chair).

Combining the above let me conclude that it's way more likely to endup with a donut.  
Or if the spin is extremely high, perhaps other torus shapes (spirograph alike).

So to me, a singularity-**point** seems highly unlikely.  
a circle, donut or thorus seems more likely, why is it that people often speak of a point?.Why isn't it a mainstream thought ?.

I hope it's okay to ask.

**Tags:** black-hole

> **Comments:**
> **username_1**: Spinning black holes don't have point singularities, they have ring singularities. And we generally expect real black holes to spin. See https://astronomy.stackexchange.com/a/20292/16685 OTOH, we aren't *certain* that singularities are physically real. Hopefully, a quantum gravity theory will resolve that issue. Also see my answer https://astronomy.stackexchange.com/a/49960/16685  
> **username_2**: Ultimately, a singularity is a mathematical construct for a part of the universe that we don't really understand. The inside of a black hole probably operates under rules we just don't know about, and whether the big divide-by-zero error is shaped like a point or a ring is not particularly important outside of some extremely arcane corners of science. "A black hole has a singularity in the middle where physics doesn't work" is good enough for anyone who isn't diving pretty deep into a complicated topic.  
> **username_3**: @username_1 We don’t really know what the nature of the singularity in a typical rotating BH. The ring singularities present in eternal Kerr are likely not representative of the general case.  
> **username_1**: @username_3 Fair point. On that note... https://physics.stackexchange.com/q/790724/123208  
> **username_4**: I don't see any literature on this, even in mainstream, talking of a point, so your question "why isn't it a mainstream thought" is misguided.  
> **username_0**: Well misguided by people speaking of a singularity point, mainly youtube science festival  
> **username_2**: @username_0 I'm not sure what you're referring to exactly, but YT science videos are usually intended for a general audience, or at least science-savvy non-experts, so they probably aren't going to go into a lot of detail about stuff like how a singularity is actually shaped (and again, I reiterate, we *do not know* if singularities are actually a real thing, let alone how they would be shaped).  
> **username_5**: A key thing to remember is that the singularity is not an object in spacetime, or the remnant of the collapsed star.  It is a feature of the solution of the equations, an "infinity" that appears at certain **spacetime** coordinates.  It is not an object at all.  It is a "where-and-when".  More confusingly the "when" is always "later".  You can never visit the singularity because there is no spacetime after the singularity.  Try hard not to think if the singularity as being a stellar remnant, it really isn't.  
> **username_1**: https://en.wikipedia.org/wiki/Physician Not to be confused with physicist.  

---

## 2 answers

### Answer by username_6 on 2024-06-07. Score: 2

One often speaks of a singularity in the context of black holes as the Einsteinian field equations show a singularity for those cases where there is no known force any longer to counter the gravity of the enclosed mass.

However that a suggested or alleged resulting singularity in spacetime might even very likely be not the truth, but is all we can safely assume with our current knowlege of gravity.

However, General Relativity does not account for quantum effects - yet those definitely DO play a role at microscopic scales. A singularity by definition is microscopic. As such: no-one knows what kind of physic laws we see *within the centre* of a black hole. Maybe we can get a step further if someone comes up with a good theory of quantum gravitation - but I'm not aware of any successful attempts yet.


---

### Answer by username_7 on 2024-06-15. Score: 2

A singularity is what the equations predict is at the center, however a point both infinitely small and infinitely dense breaks down the known laws of physics and our current understanding of physics cannot tell us exactly what occurs around that point. A torus or even a sphere/disc shaped singularity could not exist, as currently our understanding is that a singularity must either be 2 or zero dimensional. A point singularity seems to be what is most often described, however it would only form from an non-rotating star, which have never been observed. Its thought that since every star observed so far rotates, every black hole would be a [Rotating black hole](https://en.m.wikipedia.org/wiki/Rotating_black_hole), with a [ring singularity](https://en.m.wikipedia.org/wiki/Ring_singularity) which is two dimensional. The event horizons of rotating black holes can indeed flatten out to a degree and have non-spherical event horizons as well. Also [planck stars](https://en.m.wikipedia.org/wiki/Planck_star) is another possibility on what may exist as apposed to a singularity.

> **Comments:**
> **username_8**: Welcome to our site, and congrats on your first answer. It's important to understand that the purpose of a Stack Exchange site is to provide *authoritative* answers, preferably supported by evidence. This is particularly relevant for science-based SE sites like ours. Answers based on "my understanding" or what "I believe" are more likely to be *opinion*, which is discouraged on SE sites; in fact, a question inviting opinions will usually be closed as quickly as possible.  
> **username_8**: "a point both infinitely small and infinitely dense is not possible" – and yet, the mathematics of black holes produces just such infinities. Channeling Galileo: "*Eppur si muove.*"  
> **username_7**: @username_8 sure thing :)  
> **username_0**: @username_8 I dont know the final answer of this  
> **username_0**: @username_8 I dont know the final answer, but if you don't start with perfect spheres, donuts could form, ring singularities, and rings surfaces 2 dimensional, which makes a bit sense. I think, blackhole emissions (hawking radiation) seem to point to a certain shape as well, as it doesn't point into random directions. Well I think the final answer is that some people do think about such, and others thinking in the larger scales find it ideal to speak of as a point.  

---

