Could a Black Hole Explain the Big Bang & CMB?

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Discussion Overview

The discussion explores the hypothesis that the universe may have originated from a giant black hole that collapsed in on itself, potentially explaining cosmic microwave background (CMB) observations. Participants examine the implications of this idea within the context of cosmology and black hole physics, touching on theoretical models and speculative mechanisms.

Discussion Character

  • Exploratory
  • Debate/contested
  • Technical explanation
  • Conceptual clarification

Main Points Raised

  • One participant proposes that the universe could have started as a giant black hole that collapsed, leading to an explosion akin to the inflationary big bang model, potentially explaining the CMB's axis of evil.
  • Another participant asserts that the universe did not originate from a black hole, arguing that such a scenario would yield different observational outcomes than those currently observed.
  • A later reply acknowledges that the idea of a black hole origin has historical roots in the quantum gravity community, referencing works by Lee Smolin and John Archibald Wheeler, suggesting it is not an inherently flawed concept.
  • Some participants discuss the lack of understanding regarding the mechanisms at play within black holes, mentioning speculative ideas about quantum effects at extreme densities that could lead to the formation of new expanding regions of space-time.
  • One participant references a recent paper by Jorge Pullin that explores the quantization of black holes and suggests that certain theoretical models could support the idea of a new universe emerging from a black hole.

Areas of Agreement / Disagreement

Participants express a range of views, with some supporting the black hole hypothesis and others contesting it. There is no consensus on the validity of the idea, and the discussion remains unresolved regarding the implications of black holes in cosmological origins.

Contextual Notes

Participants note limitations in current understanding of black hole mechanics and the speculative nature of proposed mechanisms for universe formation from black holes. There are references to unresolved mathematical steps and the dependence on specific theoretical models.

aaron_ironmon
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Hi all, I'd like to apologise in advance for the layman's terminology in the idea below. I'd be delighted to get any feedback/thoughts on whether CMB observations could be explained in this way.

Could the universe have started as a giant black hole that reached a critical mass and collapsed in on itself?

White dwarfs, neutron stars and black holes have all collapsed to a denser state under the effects of gravity. Maybe black holes can collapse too. Imagine a black hole becomes so massive that it can no longer maintain itself against the huge gravitational forces. The black hole might collapse in on itself and then explode with all the predicted effects of the inflationary big bang model. In order for critical mass to be reached material would need to be falling into the black hole and this spiralling disc of material might explain the so-called axis of evil that appears in the CMB. An inflationary model expanding into non-nothingness might also produce the less uniform CMB of experimental observation.

Best regards

Aaron Ironmonger
 
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This question has been asked here approximately 4,297 times. Please do a forum search.

Oh, and the answer is no.
 
Well that told me!
 
the universe did not start from a black hole. the singularity described at the beginning is where we can no longer describe it with mathematics etc. A BH beginning would have different observations than what we see. In the BH the universe would be expanding from a central point. In observations expansion is the same everywhere no matter what coordinate you choose.
 
aaron_ironmon said:
Hi all, I'd like to apologise in advance for the layman's terminology in the idea below. I'd be delighted to get any feedback/thoughts on whether CMB observations could be explained in this way.

Could the universe have started as a giant black hole ...?
...

Well you introduce this as a layman's question and as such it is a pretty good one! In slightly different terms the essential idea has been floating around since 1992 or so in the quantum gravity community and has at least one wide-audience book written about it (The Life of the Cosmos, by Lee Smolin) as well as a number of scientific papers.

The original idea is said to go back even earlier to John Archibald Wheeler, a renowned Princeton physicist who was Richard Feynman's PhD advisor.

So it's not a kook idea, or automatically wrong. It's a strange idea that is hard to get a grip on. But it has a good pedigree.

But if you are interested in cosmology you had probably start by getting better acquainted with the basic concepts and more or less "known" stuff as widely understood, rather than blue-sky wild ideas (even if they have good pedigree).

The reason is we don't have a good idea of the MECHANISM at work in the pit of a BH. It may be that there is a threshold mass and if a BH has that mass its center will reach a threshold density at which quantum effects (that only kick in at extreme density) cause gravity to reverse and REPEL instead of attract and then a new expanding region of space-time would form "out the back door" so to speak. A separate expanding region. You might call it a "baby" universe but it might grow up to be what we think of as full size.

There are some ideas for mechanisms---ideas for how a new universe (invisible to us, out the back door of a black hole that we can't see into) could get all the requisite matter---ideas for how quantum effects would appear at extreme density and cause contraction to rebound and re-expand---ideas for how the new universe could have its own "inflationary" episode similar to ours. But those ideas are what is called "speculation". Not grounded on observation, more what-iffy.

So if you are just beginning to learn cosmology you probably would not find you could get very far along that line.

But in case anyone is interested in pursuing it Jorge Pullin just posted a new paper about this.
It is fairly cautious. In a certain theoretical model of cosmology called Loop Quantum Cosmology the mechanisms exist, so based on that theoretical model, it would work, according to what he finds. I will get the link to Pullin's article.
 
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http://arxiv.org/abs/1302.5265
Loop quantization of the Schwarzschild black hole
Rodolfo Gambini, Jorge Pullin
(Submitted on 21 Feb 2013)
We quantize spherically symmetric vacuum gravity without gauge fixing the diffeomorphism constraint. Through a rescaling, we make the algebra of Hamiltonian constraints Abelian and therefore the constraint algebra is a true Lie algebra. This allows the completion of the Dirac quantization procedure using loop quantum gravity techniques. We can construct explicitly the exact solutions of the physical Hilbert space annihilated by all constraints. New observables living in the bulk appear at the quantum level (analogous to spin in quantum mechanics) that are not present at the classical level and are associated with the discrete nature of the spin network states of loop quantum gravity. The resulting quantum space-times resolve the singularity present in the classical theory inside black holes.
4 pages. To appear in Physical Review Letters (2013)

Jorge presented the finding last week at a major international conference in Europe: the triennial GR20. Here is the summary of his talk:

==http://gr20-amaldi10.edu.pl/userfiles/book_05_07_2013.pdf ==
Complete quantization of vacuum spherically symmetric gravity
Pullin J
We find a rescaling of the Hamiltonian constraint for vacuum spherically symmetric gravity that makes the constraint algebra a true Lie algebra. We can implement the Dirac quantization procedure finding in closed form the space of physical states. New observables without classical counterpart arise. The metric can be understood as an evolving constant of the motion defined as a quantum operator on the space of physical states. For it to be self adjoint its range needs to be restricted, which in turn implies that the singularity is eliminated. One is left with a region of high curvature that tunnels into another portion of space-time. ...
==endquote==
 
Last edited by a moderator:
This article is a good, non pop media, review of observational cosmology. There is no math in it, however it explains many of the key details on todays cosmology.

http://arxiv.org/abs/1304.4446
 

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