Doubts about Big Bang alternatives

[physics it is]

Hello everyone,
I am a 14-year-old student from India, deeply interested in theoretical physics and cosmology. I am working on building my foundation in mathematics (currently in Class 9), but I have been working through a conceptual thought experiment regarding the origins of our universe and the Big Bang. I would love to get your feedback on the physical feasibility and roadblocks of this hypothesis.
The Hypothesis:
Suppose a highly advanced civilization (or multiple civilizations) in a parent universe engaged in a massive-scale conflict resulting in an extreme release of energy via nuclear fusion. Following Einstein's mass-energy equivalence (E=mc²), the local energy density becomes high enough to severely distort the local space-time fabric, resulting in the formation of a traversable Einstein-Rosen bridge (wormhole).
If a localized region of matter/space-time from that parent universe was pulled into this wormhole at extreme relativistic speeds, could the "exit" of this wormhole into a new region or a vacuum state manifest as the phenomenon we observe as the Big Bang?
Essentially, this treats the Big Bang not as a singularity arising from nothing, but as the high-energy output (similar to a white hole solution) of a space-time rupture from a prior state of existence.
My Questions for the Forum:
1. I know that Sir Roger Penrose’s Conformal Cyclic Cosmology (CCC) and Nikodem Popławski’s theories about universes inside black holes look at cyclic or parent-child universes. How closely does this concept align with current mathematical models of White Holes?
2. What are the primary quantum mechanical or general relativistic constraints that would prevent a high-energy density event (E=mc²) from ripping space-time to create a macro-wormhole?
3. Since we currently lack observational data before t=0, what theoretical frameworks (like Loop Quantum Gravity or String Theory) address the possibility of a "pre-Big Bang" structural origin like this?
I welcome all rigorous critiques, mathematical corrections, and reading recommendations to help me refine my understanding!
Thank you.

 

[PeroK]

The Big Bang starts from a "hot, dense" state.

This is not the science-fiction forum!

 

[PeterDonis]

Hi @physics it is and welcome to Physics Forums.

First, please be aware that personal speculations are off limits for discussion here. Your "hypothesis" at the very least is close to that. But the actual questions you ask are legitimate questions about how we model our universe, so I'll respond to them.

1. I know that Sir Roger Penrose’s Conformal Cyclic Cosmology (CCC) and Nikodem Popławski’s theories about universes inside black holes look at cyclic or parent-child universes. How closely does this concept align with current mathematical models of White Holes?

Not at all. White holes are not something that can arise from a prior state, the way a black hole can arise from the gravitational collapse of a massive object. That is why physicists consider white holes to be unphysical. The various hypotheses about "cyclic" universes do not make use of the "white hole" solution in General Relativity.

2. What are the primary quantum mechanical or general relativistic constraints that would prevent a high-energy density event (E=mc²) from ripping space-time to create a macro-wormhole?

General Relativity does not permit such a thing at all. There is no way in GR to "rip" spacetime.

We do not have a viable theory of quantum gravity, so we can't say whether there might be quantum gravity phenomena that would look like what you describe. You will see speculations along these lines in some pop science books, but they are just that--speculations. Nobody has any way of testing them and we don't have any theory that deals with them. So unfortunately there's nothing useful we can say about this from a physics standpoint at our current level of knowledge.

3. Since we currently lack observational data before t=0, what theoretical frameworks (like Loop Quantum Gravity or String Theory) address the possibility of a "pre-Big Bang" structural origin like this?

First, we don't know for sure that there was a "t = 0" initial singularity in our universe. In some models, such as eternal inflation models, there isn't one. Nor is there one in "cyclic" or "bounce" models.

In models in which there is an initial singularity at t = 0, there cannot be anything before it; that's what "initial singularity" means. Such a thing can't "come from" anything else.

I'm not aware of anything useful that candidate hypotheses for a quantum gravity model, like loop quantum gravity or string theory, have to say about this issue.

 

[sbrothy]

I hate to look like I really know what I'm talking about, compared to the moderators here. Still, this being a highschool thread, I think that besides Penrose's sketchy (albeit fanciful) CCC idea (maybe not strictly falsified, but for sure frowned upon in the physics community), the idea that a black hole is something you can "travel through" and emerge "somewhen" else isn't something I would sign up for. I think that, at least for now, that particular idea belongs in the scifi drawer. And yes, there's no t <= 0. I doubt we're there yet.

 

[PeterDonis]

the idea that a black hole is something you can "travel through" and emerge "somewhen" else isn't something I would sign up for

There have been speculations about black holes spawning "baby universes" (Hawking published a pop science book with a title along those lines), but again, they're just that--speculations. Nobody has any actual model, even a hypothetical one, of such a thing.

 

[sbrothy]

There have been speculations about black holes spawning "baby universes" (Hawking published a pop science book with a title along those lines), but again, they're just that--speculations. Nobody has any actual model, even a hypothetical one, of such a thing.

I'm aware. I found the idea so interesting (I mean universes with different constants and whatnot!) An intriguing idea!) that I read a ton, but I ended up with a disappointing feeling. Hence my comment. I could probably dig up the paper that killed my hope but I'd have to go through a lot.....

 

[sbrothy]

Indeed, to paraphrase an apocryphal old lady: It's black holes all the way down (and up).

 

[PeroK]

I'm aware. I found the idea so interesting (I mean universes with different constants and whatnot!) An intriguing idea!) that I read a ton, but I ended up with a disappointing feeling. Hence my comment. I could probably dig up the paper that killed my hope but I'd have to go through a lot.....

There was this thread recently:

T

High School Thread 'Questions about Schwarzschild Cosmology and White Hole Big Bangs'

Sep 3, 2026

Hi everyone,
I'm a student who is really interested in cosmology. I was thinking about how both the Big Bang and black holes start with a singularity, and I ended up finding out about Schwarzschild Cosmology and Nikodem Popławski’s model (where our universe expands like a white hole inside a parent black hole).
Since I'm just a beginner, I wanted to ask the experts here a couple of questions to help me understand:

1. How does a collapsing black hole turn into an expanding white hole? What is the physics behind that "bounce"?
2. If this theory is right, does it mean the black holes we...

• Tanya Li
• Replies: 7
• Forum: Astronomy, Astrophysics, Cosmology