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Research suggests Big Bang may have taken place inside a black hole

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Re: Research suggests Big Bang may have taken place inside a black hole

#241

Post by codethief »

kannanvijayan wrote: post #94

Oh I have so many questions on this topic. I've often wondered about this. I don't have any direct physics training, but it's something that felt really plausible after I learned that the mass of a black hole is linearly proportional to its swarzschild radius. As the size of the black hole goes up, its overall density must decrease. Combined with the other observation that our universe has uniform density at large sc…

> Combined with the other observation that our universe has uniform density at large scales

s/has/had at the time of recombination

It is largely an assumption of LCDM that we can treat the universe as practically homogeneous throughout its entire evolution but potentially not a very well-founded at that [0, 1].

> I always felt uncomfortable with that characterization. It seems more reasonable to me to think of dark energy as _negative energy_ - i.e. a loss of overall energy.

Your intuition is correct. If the Lambda term in the Einstein field equations is moved over to the side of the energy momentum tensor, it takes on the role of a negative contribution (provided Lambda > 0, as observations seem to indicate).

> In a classical system, two things moving away from each other stores potential energy that can be recouped at some later time. Dark energy doesn't work this way - things accelerate away from each other the further apart they are. From a global perspective, it's an energy loss.

Note that there is no global energy conservation in General Relativity[2], only at a local scale[3]. Heck, you'll already struggle to define what the energy is of a given piece of spacetime in a meaningful and generic manner[4, 5]. In other words, violations of energy conservation due to spacetime expanding or contracting (a strictly non-local phenomenon), like in the case of the cosmic redshift, are expected and our intuition from classical mechanics only takes you so far.

> It somehow feels more appropriate to me to think of dark energy as energy being extracted out of the universe, in some form never to return.

Dark energy aka the cosmological constant term in the Einstein field equations is a constant term, as the name suggests. Yes, there can be energy loss due to spacetime expanding (see above) but that doesn't change the gravitational constant.

[0]: https://en.wikipedia.org/wiki/Cosmic_web

[1]: https://en.m.wikipedia.org/wiki/Inhomogeneous_cosmology

[2]: https://en.m.wikipedia.org/wiki/Conservation_of_energy

[3]: https://en.m.wikipedia.org/wiki/Stress%E2%80%93energy_tensor

[4]: https://arxiv.org/abs/1510.02931

[5]: https://en.m.wikipedia.org/wiki/Mass_in_general_relativity

Re: Research suggests Big Bang may have taken place inside a black hole

#242

Post by 1270018080 »

avmich wrote: post #234

> But how come Penrose’s theorems forbid out such outcomes? It’s all down to a rule called the quantum exclusion principle, which states that no two identical particles known as fermions can occupy the same quantum state (such as angular momentum, or “spin”). > And we show that this rule prevents the particles in the collapsing matter from being squeezed indefinitely. As a result, the collapse halts and reverses. The…

With enough mass, there is enough energy from gravity to put all fermions into different states, so the collapse continues

Re: Research suggests Big Bang may have taken place inside a black hole

#243

Post by cwmoore »

DrammBA wrote: post #194
bmacho wrote: post #126

Earlier quoted context omitted.

We have no theories working at those conditions. Wiki says > General relativity also predicts that the initial state of the universe, at the beginning of the Big Bang, was a singularity of infinite density and temperature.[6][obsolete source] However, classical gravitational theories are not expected to be accurate under these conditions, and a quantum description is likely needed[7]. https://en.wikipedia.org/wiki/Gr…

> [6][obsolete source] I didn't know but apparently wikipedia treats old sources as obsolete, doesn't matter if there's new information or not that would make it obsolete. I wonder if any sources supporting the notion that the earth is round must be updated every couple of years with a new source or study.

That exemplifies a much deeper problem than good information, “Good Law”: https://en.m.wikipedia.org/wiki/Good_law

As an aside, the earth is almost flat, just not nearly as flat as the Universe.

Re: Research suggests Big Bang may have taken place inside a black hole

#245

Post by kgwxd »

afarah1 wrote: post #196

Interesting read, but even if we assume the author is correct, and the cosmos formed as a black hole in a larger universe, the question remains, how did this larger universe formed, then? Might just be impossible to know.

if we assume the author is correct, it would cease to be a scientific endeavor.

Re: Research suggests Big Bang may have taken place inside a black hole

#246

Post by hshshshshsh »

nathan_compton wrote: post #226
hshshshshsh wrote: post #185

Earlier quoted context omitted.

Assume God exists. Various isolated cultures are going to come up with different names for God. This like saying which Sun? Surya, Ra or Helios? All are different names of sun. But there is only one sun.

On the other hand, there are a lot of stars and different cultures might give them different names and yet there really are many of them. Furthermore, assume God doesn't exist. Lots of cultures might invent god for various reasons and they'd naturally have different names and attributes for them, which in fact seems to be the current state of affairs. In fact, if we assume God exists and is actively in communication…

Why do you think God will have a name? Name is used by humans to identity a person among a lot of other persons. Why will God have a name if it is the only thing in existence?

To answer the question of why humans give name to God. It's to make god more relatable so that they can workshop it. And use devotion to come closer with it. Look up Bhakti Yoga.

Re: Research suggests Big Bang may have taken place inside a black hole

#247

Post by ogou »

Frost1x wrote: post #129
ogou wrote: post #108

The word "research" in this title is a handy placeholder for indeterminate conjecture. No research happened, it's a theory he made up.

I would argue that theory is a critical part of the research process and is therefore research. There’s of course a line between simply coming up with ideas that are quickly provably wrong or inconsistent vs generating ideas that are consistent and not quickly falsified. It’s especially valuable the ideas are falsifiable and it seems like this is the case here. As such, theory finds patterns in existing knowns, makes…

A research paper makes use of multiple sources of known provenance and various degrees of authority and relevance. It tries to establish a consensus of knowledge, as close to fact as possible. The phrase "research suggests" is an appeal to authority that implies some kind of academic rigor. A theory paper, which is still useful and important, can be published without any kind of authority. You can just make things up.

Re: Research suggests Big Bang may have taken place inside a black hole

#248

Post by wrcwill »

while it doesn't take away from the article, i find it worrying that it seems mostly written with chatgpt

"This is not just a technical glitch; it’s a deep theoretical problem that suggests we don’t really understand the beginning at all."

"The bounce is not only possible – it’s inevitable under the right conditions."

ugh

Re: Research suggests Big Bang may have taken place inside a black hole

#249

Post by timewizard »

afarah1 wrote: post #196

Interesting read, but even if we assume the author is correct, and the cosmos formed as a black hole in a larger universe, the question remains, how did this larger universe formed, then? Might just be impossible to know.

It may just be that the physical conditions of our universe just prior to the big bang are indistinguishable from that of the interior of black holes.

In that sense black holes are areas where our universe has reverted from it's low entropy state all the way back to the initial nearly infinite entropy state.

Re: Research suggests Big Bang may have taken place inside a black hole

#250

Post by DrammBA »

cwmoore wrote: post #243
DrammBA wrote: post #194

Earlier quoted context omitted.

> [6][obsolete source] I didn't know but apparently wikipedia treats old sources as obsolete, doesn't matter if there's new information or not that would make it obsolete. I wonder if any sources supporting the notion that the earth is round must be updated every couple of years with a new source or study.

That exemplifies a much deeper problem than good information, “Good Law”: https://en.m.wikipedia.org/wiki/Good_law As an aside, the earth is almost flat, just not nearly as flat as the Universe.

> As an aside, the earth is almost flat, just not nearly as flat as the Universe.

Source? And make sure to update your response every few years.

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