How is the Big Bang producing singularity not a black hole?

Click For Summary

Discussion Overview

The discussion revolves around the question of why the singularity associated with the Big Bang is not considered a black hole. Participants explore the nature of singularities, the conditions of the early universe, and the differences between black holes and the Big Bang singularity.

Discussion Character

  • Debate/contested
  • Conceptual clarification
  • Exploratory

Main Points Raised

  • Some participants question the assumption that the Big Bang singularity is a black hole, noting that black holes are regions where matter falls in and cannot escape, whereas the Big Bang involved matter emerging.
  • There is confusion regarding the nature of the singularity at the Big Bang, with some asserting it is infinitely dense while others argue it was not infinitely dense and was instead a plasma of indeterminate size.
  • Participants discuss the breakdown of mathematical models at singularities, suggesting that both Big Bang and black hole singularities indicate a lack of understanding rather than a direct comparison.
  • Some argue that the early universe's rapid expansion prevented the formation of a black hole, as the matter and energy were moving apart too quickly to collapse under gravity.
  • A few theorists propose that gravity may have been repulsive under the conditions of the early universe, although this does not fully explain the observed expansion rates.
  • There is a discussion about whether an infinite universe implies infinite mass/energy, with no consensus on the universe's finiteness or infiniteness.
  • Some participants speculate on the relationship between black holes and the Big Bang, suggesting ideas such as the Big Bang being a black hole in another universe or involving concepts like white holes.
  • There are misunderstandings and clarifications regarding terminology, such as the distinction between "black hole" and "naked singularity."

Areas of Agreement / Disagreement

Participants express multiple competing views regarding the nature of the Big Bang singularity and its relationship to black holes. The discussion remains unresolved, with various hypotheses and interpretations presented without consensus.

Contextual Notes

Limitations include the unclear definitions of singularities and the early universe's conditions, as well as unresolved mathematical aspects related to the discussion.

John Light
Messages
9
Reaction score
0
Hey, so I've been wondering about this question for a while and was wondering if anyone could support the Big Bang theory in this respect or anything else. Just wondering if anyone has an answer that might aid me in understanding this, thanks.
 
Astronomy news on Phys.org
I'm wondering why you would think the Big Bang is a black hole in the first place. A black hole is a region into which matter falls and can't escape; but matter comes *out* of the Big Bang.
 
What I was confused about was this though: if the singularity that started the Big Bang is so infinitely dense, how did it not become a black hole?
 
John Light said:
What I was confused about was this though: if the singularity that started the Big Bang is so infinitely dense, how did it not become a black hole?

A 'singularity" means that our math has broken down and started given us nonsense for answers. You could say that we don't know enough about how physics works at that scale to avoid getting infinity as an answer. It is thought that future advances in our understanding of physics will lead to a black hole without a singularity.

Also, the normal rules for black holes do not apply to the very early universe because it was dominated by spacetime expansion, whereas a regular black hole is not.
 
You are misunderstanding the meaning of the term "singularity" AND you are misinformed about the density of the early universe.

"Singularity" means "we don't know WHAT is going on because the math model breaks down". The big bang singularity and black hole singularities are not believed to be in any way related or similar, they are just both places where the respective math breaks down and so have the same generic name.

The early universe (at about one Plank time) is not believed to have been infinitely dense, nor was it a point. It was a plasma of indeterminate size (possibly infinite in expanse) of a density and energy pretty much beyond human comprehension, but not infinite in anything other than possibly the expanse.
 
Drakkith said:
A 'singularity" means that our math has broken down and started given us nonsense for answers. You could say that we don't know enough about how physics works at that scale to avoid getting infinity as an answer. It is thought that future advances in our understanding of physics will lead to a black hole without a singularity.

Also, the normal rules for black holes do not apply to the very early universe because it was dominated by spacetime expansion, whereas a regular black hole is not.

Damn. Beat me by 2 minutes. Have you been taking speed typing lessons? :smile:
 
John Light said:
What I was confused about was this though: if the singularity that started the Big Bang is so infinitely dense, how did it not become a black hole?

It actually wasn't infinitely dense, as other commenters have pointed out; but the more important point here is that, as Drakkith pointed out, the universe right after the Big Bang was expanding very fast, fast enough to overcome the attractive gravity of the matter and energy that was present; in other words, the matter and energy were flying apart too fast to collapse into a black hole.
 
Ok, thank you very much all of you, this has all been really helpful.
 
Some theorists have posited gravity may be repulsive under conditions that existed at the time of the big bang, but, that explanation does not appear sufficient to explain superluminal expansion in the very early universe.
 
  • #10
also you need pre-existing space for a black hole to exist in.
 
  • #11
phinds said:
It was a plasma of indeterminate size (possibly infinite in expanse) of a density and energy pretty much beyond human comprehension, but not infinite in anything other than possibly the expanse.
If it was infinite in expanse, would it not also be infinite in energy?
 
  • #12
If the universe is in fact infinite, then it would also have infinite mass/energy. If its finite then its energy content is also finite. We still do not know if the universe is infinite or finite. However if its infinite now then it was infinite in the past and vise versa
 
  • #13
It would not be a black whole because the energy used would combust not create a life killing wormhole
Sent from my iPod touch using Physics Forums
 
  • #14
surely a black hole would only exist in pre-existing space. otherwise it would just be a "naked singularity". the descriptor "black hole" just describes the even horizon does it not?
 
  • #15
atombuster said:
It would not be a black whole because the energy used would combust not create a life killing wormhole

HUH ? What is a "life killing wormhole" ?
 
  • #16
Yes, I like that idea. The big bang was a black hole in another universe and our universe is a white hole at the other end of the wormhole that resulted...
 
  • #17
Chronos said:
Yes, I like that idea. The big bang was a black hole in another universe and our universe is a white hole at the other end of the wormhole that resulted...

I don't, a black hole doesn't have consistent feeding rates, if we were part of the white hole we should see variations in expansion rates due to variations in BH feeding rates
 
  • #18
Yes but the black whole would be very small and condense and would more than likely blow up
 
  • #19
Well I mean a black whole that would have killed all the living, if there where any, Homo sapiens.
 
  • #20
atombuster said:
Well I mean a black whole that would have killed all the living, if there where any, Homo sapiens.

What are you talking about?
 
  • #21
"hole", not "whole" :mad:
 
  • #22
I am saying the explosion would have blown all the planets away and or the black hole, if there was one, wold have sucked all the planets up
 
  • #23
atombuster said:
I am saying the explosion would have blown all the planets away and or the black hole, if there was one, wold have sucked all the planets up

What explosion? I literally have no idea how your posts relate to the thread topic.
 
  • #24
They do because you want to know how the singularity of the Big Bang did not resolt in a black hole and I am saying that it probably did not make a black hole because the world probably get sucked in
 
  • #25
atombuster said:
They do because you want to know how the singularity of the Big Bang did not resolt in a black hole and I am saying that it probably did not make a black hole because the world probably get sucked in

It didn't make a black hole because the geometry of spacetime at the time of the big bang was dynamic, not static like it is around normal black holes. What that means is that the expansion of space allows matter to separate even though it would have formed a black hole in non-expanding, local space.
 
  • #26
I agree it did not form but it would have been horrible if it did form
 

Similar threads

High School How Can Black Holes Vary in Size if They Are Singularities?
  • · Replies 20 ·
Replies
20
Views
4K
High School Is the Universe Inside a Black Hole?
  • · Replies 28 ·
Replies
28
Views
7K
Undergrad Black holes with a naked singularity?
  • · Replies 7 ·
Replies
7
Views
4K
Undergrad The initial density of an object and its compression into a black hole
  • · Replies 17 ·
Replies
17
Views
6K
High School Are black holes related to the big bang?
  • · Replies 8 ·
Replies
8
Views
6K
Undergrad Early Universe massive Black Holes question
  • · Replies 10 ·
Replies
10
Views
3K
Undergrad Does Kerr's argument against singularities apply to all black holes?
  • · Replies 12 ·
Replies
12
Views
3K
High School Could Black Hole Collisions Trigger a Cyclical Big Bang and Universe Rebirth?
  • · Replies 19 ·
Replies
19
Views
3K
Undergrad Kerr disputes singularities in Kerr Black Holes
  • · Replies 7 ·
Replies
7
Views
4K
Undergrad What is the Connection Between Black Holes and the Big Bang?
  • · Replies 2 ·
Replies
2
Views
3K