<p>Yes, an event horizon will form once escape velocity exceeds the speed of light. It does not necessarily require a singularity inside it.</p>

<p>However, there is no known physics that would allow any non-point-like object to exist inside an event horizon. It is hard to see how any traditional forces would be able to support an object in such case, and for quantum mechanics we simply do not have the theory that'd be valid in such high gravitational field. </p>

CC BY-SA 4.0
2020-01-07T21:57:06.410Z
In the context of general relativity, the formation of a singularity is inevitable inside an event horizon. (This is the essence of the Penrose-Hawking singularity theorems.)
TimRias
CC BY-SA 4.0
2020-01-10T20:30:39.630Z
I believe that you meant to say no known physics would allow any non-point-like object to SURVIVE inside an event horizon.  It is physically possible, momentarily, when a black hole forms, for it to have an event horizon whilst the interior material  has not yet formed a singularity.
eshaya
CC BY-SA 4.0
2023-06-16T16:58:53.187Z
"momentarily" There's the rub. The inside of the event horizon is essentially cut off from the passage of time as observed on the outside. It would depend on how much time within the event horizon is slowed in comparison to the outside.
EvilSnack
CC BY-SA 4.0
2020-01-07T16:13:00.717Z
2020-01-07T16:13:00.717Z
tuomas
<p>I'm basing this hypothesis on the theories around how an outside observer watching something fall into a black hole will never actually see the thing pass the event horizon. And secondly that from the perspective of the thing falling in, the surrounding universe would accelerate to see the end of the universe.</p>

<p>On that second point, the "end of the universe" from my understanding would be up until the black hole evaporates.</p>

<hr>

<p>So the question. Is it possible for an event horizon to form; not necessarily from a singularity, but merely from there being enough compressed mass existing within the boundaries that an event horizon forms?</p>

<hr>

<p>The implication from this if it has any merit would be in my opinion, that there are no singularities currently in existence and that there indeed might never be one, because currently I don't understand how something "inside" a black hole is capable of moving at all (I assume that to do so mass would need to move faster than light), suggesting that the entirety of a stellar remnant's mass is stuck in place both inside and on the surface of the event horizon.</p>

<p>EDIT: Re-reading that last paragraph I've confused myself a little, mass wouldn't necessarily be "stuck", but if it did move at all, it would be moving light speed, which is a paradox in itself?</p>

CC BY-SA 4.0
2020-01-07T15:15:15.540Z
I suppose a simpler way of asking this is; could a newton star be at the center of an event horizon? or perhaps some other smaller and denser object?
Flosculus
<black-hole><singularity>
Does a black hole necessarily contain a singularity?
Flosculus
# Does a black hole necessarily contain a singularity?

(Asked by: username_0 on 2020-01-07)

I'm basing this hypothesis on the theories around how an outside observer watching something fall into a black hole will never actually see the thing pass the event horizon. And secondly that from the perspective of the thing falling in, the surrounding universe would accelerate to see the end of the universe.

On that second point, the "end of the universe" from my understanding would be up until the black hole evaporates.

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So the question. Is it possible for an event horizon to form; not necessarily from a singularity, but merely from there being enough compressed mass existing within the boundaries that an event horizon forms?

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The implication from this if it has any merit would be in my opinion, that there are no singularities currently in existence and that there indeed might never be one, because currently I don't understand how something "inside" a black hole is capable of moving at all (I assume that to do so mass would need to move faster than light), suggesting that the entirety of a stellar remnant's mass is stuck in place both inside and on the surface of the event horizon.

EDIT: Re-reading that last paragraph I've confused myself a little, mass wouldn't necessarily be "stuck", but if it did move at all, it would be moving light speed, which is a paradox in itself?

**Tags:** black-hole, singularity

> **Comments:**
> **username_0**: I suppose a simpler way of asking this is; could a newton star be at the center of an event horizon? or perhaps some other smaller and denser object?  

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## 1 answers

### Answer by username_1 on 2020-01-07. Score: 0 | Accepted answer

Yes, an event horizon will form once escape velocity exceeds the speed of light. It does not necessarily require a singularity inside it.

However, there is no known physics that would allow any non-point-like object to exist inside an event horizon. It is hard to see how any traditional forces would be able to support an object in such case, and for quantum mechanics we simply do not have the theory that'd be valid in such high gravitational field.

> **Comments:**
> **username_2**: In the context of general relativity, the formation of a singularity is inevitable inside an event horizon. (This is the essence of the Penrose-Hawking singularity theorems.)  
> **username_3**: I believe that you meant to say no known physics would allow any non-point-like object to SURVIVE inside an event horizon.  It is physically possible, momentarily, when a black hole forms, for it to have an event horizon whilst the interior material  has not yet formed a singularity.  
> **username_4**: "momentarily" There's the rub. The inside of the event horizon is essentially cut off from the passage of time as observed on the outside. It would depend on how much time within the event horizon is slowed in comparison to the outside.  

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