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

In summary: Big Bang theory or have an explanation for it not becoming a black hole?In summary, the conversation discusses the concept of the Big Bang theory and its relation to black holes. It is explained that the singularity that started the Big Bang is not infinitely dense and that the normal rules for black holes do not apply to the early universe due to spacetime expansion. Some theories suggest that gravity may have been repulsive at the time of the Big Bang, but this does not fully explain the rapid expansion. The conversation also touches on the idea of the Big Bang being a black hole in another universe and our universe being a white hole at the other end of a wormhole. However, there is no clear evidence or explanation supporting this idea
  • #1
John Light
9
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
  • #2
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.
 
  • #3
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?
 
  • #4
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.
 
  • #5
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.
 
  • #6
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:
 
  • #7
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.
 
  • #8
Ok, thank you very much all of you, this has all been really helpful.
 
  • #9
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
 

1. How can the Big Bang produce a singularity if it is not a black hole?

The Big Bang is often described as a singularity because it represents the beginning of the universe, a point of infinite density and temperature. However, this singularity is different from a black hole singularity in that it is not caused by a region of space with a strong gravitational pull. Instead, it is the result of an incredibly rapid expansion of the universe.

2. How does the Big Bang singularity differ from a black hole singularity?

A black hole singularity is caused by the gravitational collapse of a massive star, resulting in an extremely dense and compact region of space. In contrast, the Big Bang singularity is the starting point of the universe and is not caused by the collapse of matter.

3. Can a black hole be formed during the Big Bang?

No, a black hole cannot be formed during the Big Bang because the conditions necessary for a black hole to form, such as a massive star collapsing, did not exist at the time of the Big Bang. The universe was too hot and dense for matter to clump together and form black holes.

4. Why is the Big Bang singularity not considered a black hole?

The Big Bang singularity is not considered a black hole because it does not possess the defining characteristics of a black hole, such as an event horizon and a strong gravitational pull. Additionally, the concept of a black hole did not exist at the time of the Big Bang.

5. Could the Big Bang singularity eventually collapse into a black hole?

No, the Big Bang singularity cannot collapse into a black hole because it is not a region of space with a strong gravitational pull. The singularity is the starting point of the universe, and as the universe continues to expand, the conditions necessary for a black hole to form will not be met.

Similar threads

I Does Kerr's argument against singularities apply to all black holes?
    • Special and General Relativity
Replies
12
Views
352
B Ultramassive Black Hole (UMB), 30 billion solar masses?
    • Astronomy and Astrophysics
Replies
4
Views
1K
B Is the Universe Inside a Black Hole?
    • Astronomy and Astrophysics
Replies
28
Views
5K
I Black holes with a naked singularity?
    • Astronomy and Astrophysics
Replies
7
Views
3K
I Kerr disputes singularities in Kerr Black Holes
    • Special and General Relativity
Replies
7
Views
1K
B Observational bias? Lack of massive black hole observations....
    • Astronomy and Astrophysics
Replies
4
Views
1K
I What is the Connection Between Black Holes and the Big Bang?
    • Special and General Relativity
Replies
2
Views
827
B Does the inertia of matter change in a black hole?
    • Astronomy and Astrophysics
Replies
2
Views
872
B Why Don't We Live Inside a Black Hole?
    • Special and General Relativity
Replies
3
Views
1K
I Why didn't the Big Bang form a Black Hole?
    • Cosmology
Replies
7
Views
879

Hot Threads

Recent Insights

Back
Top