Ask HN: Is it black holes all the way up?

[zoroaster]

This is something of a rant, but I would greatly appreciate your reflections as it's a subject that is very confusing for me. Many of you are much smarter than I am, so any thoughts you have around this would be appreciated!

People recently have been positing that the big bang occurred as result of a black hole (i.e. black hole sucks up more and more material, gains more mass, until it explodes in a big bang into a new universe).

My question is, if this is the case, is there (1) another universe "above"? And is there another universe "above" that eternally? Or is it (2) more the case that our existing universe expands, it reaches an edge of maximum expansion, and a gravity-like counter force causes it to collapse in on itself, until it again repeats the big bang process (eternal recurrence)?

Take the first example. If the conditions at the bottom of two black hole "singularity"s are the same - you would expect parallel, equal universes to be generated each time. Copies of the same universe generated over and over again with each black hole. If the conditions were slightly different (i.e. one black hole has slightly more quarks than another), you might have a "parallelish" universe arise where with slightly different initial conditions you experience vastly different results (chaos theory, small changes in initial conditions).

If the second were true, given no energy / mass would be leaving the system, you'd expect the same situation to recur eternally. The "universe" as we experience it would be bounded on one side in time by the "singularity" and on another side in time by the "edge" (the point of maximum expansion) creating a fixed, spatiotemporal object. Why does this spatiotemporal universe marble exist and what exists outside of it?

I can't wrap my head around this. Which scenario is more likely? Does any of this make any sense? If the answer is "we don't know", do you think there is a way to ever answer these questions?

It seems like we're trapped in some sort of strange, fractalian experiment.

[LinuxBender]

PBS Space Time [1] have many videos on various theories about this if you have some time to kill. I tend to lean towards the possibility that I am in the video game "Roy" [2]

[1] - https://www.youtube.com/@pbsspacetime/search?query=black%20h...

[2] - https://www.youtube.com/watch?v=MH_QCIhSHLs

[zoroaster]

Thank you for your feedback! I'll definitely check these out. The whole "simulation theory" thing seems to be a fun idea. Are we living in a petri dish experiment aimed at finding an optimal outcome? An experiment where life situations are generated many times with slight variants to examine all possible outcomes in "universe" life simulations?

The jump from matter / elements to RNA also doesn't make sense to me - so maybe there's a drop in the petri dish to explain life arising from nothing.

It's overwhelmingly mysterious & confusing :(

[rdtsc]

PBS spacetime is a fantastic series, highly recommended. At least for me it’s at the right technical level, that is to say just a tad above amateur.

[zoroaster]

Your first link and one of the videos there (https://www.youtube.com/watch?v=jeRgFqbBM5E) was a huge relief and interesting dive into the q - thanks again for sending it.

[somat]

I don't think it is a real theory, more like science fiction around the mysteries of the big bang, the universe, and the general weirdness of black holes.

But it is not that black holes explode into the universe, it is that the knowable universe is in a black hole. like I said science fiction, the part I like is it explains(It does not really, again I repeat no actual science) why time as a dimension only goes one way. just like once you pass the event horizon of a black hole there is no "out", you have lost half a dimension, inside the event horizon we call the universe, the half dimension we are missing is the out direction of the dimension we call time.

[BWStearns]

I'd watch a scifi movie with that technobabble as the premise.

[defrost]

> If the conditions at the bottom of two black hole "singularity"s are the same - you would expect parallel, equal universes to be generated each time.

That's a strong no (for any sufficiently complex physical setup with moving parts, falling glasses won't shatter the same way twice).

Two things here are relevant:

1) Lorentz (Butterfly) and Smale (Horseshoe Map) both proved that in some physical systems you can always find initial conditions that are very close (for any arbitary epsilon of "close") that none the less end up far away from each other as time passes.

ie: Unless the initial starting points are absolutely precisely identical without question, then "close enough" isn't good enough to guarentee an identical outcome in the presence of "strange attractors"

2) The Uncertainty Principle tells us that at a fine enough grain (within a certain epsilon) initial conditions are like jelly - you cannot nail them to the wall and declare two systems identical.

[zoroaster]

Yes, note that I say the equal universes situation only occurs if the conditions are the same (which I agree is unlikely). They would have to be exactly the same to result in copy universes given even the slightest variation in initial conditions would compound into vastly different outcomes.

I think, in the black holes example this outcome is unlikely given even slightly more matter or quarks absorbed would differentiate the system. This would be the "parallelish" outcomes where slightly differences would compound over time. But if there's a limiting condition that only allows for one starting point, then you get the same duplicate outcomes.

In the same way that certain elements consistently arise as a result of fusion in a star, perhaps the same types of universes might arise here. You might have a "Hydrogen" universe, a "Helium" universe, an "Iron" universe dependent on the threshold that initiates a certain "big bang" / that create initial starting points that are "absolutely, precisely identical without question". This is a bit out there, probably wrong. I have no idea.

I'm not sure I'm explaining my thinking very well, but if only so much energy / matter can break through the other side of a black hole and it breaks through in the same way every time then you would get parallel, equal universes.

I am a huge fan of your usage of chaos theory to address this question - I appreciate it.

[maxerickson]

What if there's an infinite, apparently random but actually fixed map underlying everything?

So like physics appears to have uncertainty but if you are outside it you can see that it's just playing back according to the map.

[dark-star]

Contrary to popular belief, black holes do not "suck up everything". The same way the sun does not "suck up everything" in our solar system. Sure, if stuff keeps colliding with the black hole, the black hole gets bigger and bigger (the same way the sun would get bigger and bigger if enough mass would fall into it). But the black hole never turns into a giant universe-eating vacuum cleaner, the same way the sun doesn't "eat" everything that gets close to it (e.g. comets pass very close but still get away... the same would happen if the sun were a black hole, and at the same distance, since the mass is the same)

On the contrary, due to the expansion of the universe, stuff tends to move further and further away from other stuff over time, so the chances of things colliding with a black hole get smaller and smaller with the age of the universe. At some point all black holes evaporate (at least according to current theories) because so little stuff falls into them that the tiny amount of hawking radiation that they radiate is enough to evaporate them over trillions of years.....

Also, the question whether "a universe before the big bang" (if such a thing exists) is "the same" as ours, or "different", doesn't really make sense. If you take all matter in the universe, heat it up so that only high-energy radiation is left, and then let it "create another universe"... . how would you define if it's "the same" or "different"? All matter has been removed and recreated. It's similar to the idea that you take a ship, any ship, and piece by piece replace every single part of the ship one by one. At the end, is it still the same ship or a different one?

To take a more traditional scientific stance, asking "what happened before the big bang" is meaningless because time didn't exist, it was created by the big bang. It's tricky to wrap your head around the concept, the same way that it's tricky to wrap your head around the concept of an "expanding universe" that seems to expand "away" from us in every direction, yet we are not in the center of it. Or that the universe might be infinitely large or even wrap around, yet we will never know because we can only ever "look" 14 billion light years far into the universe. It could be that after travelling for 20 billion light years we wouldn't reach the end of the universe (because it has no end) but instead land back on earth.

Some questions can never be answered because of physics. They will forever be unknown because answering them either makes no sense, or none of the answers you could give could ever be verified/falsified. So: does asking these questions even make sense?

[zoroaster]

I think asking the question makes sense even if the answer is "no answer". It's interesting to think about and to explore, and helpful to get the input of others.

By the "sameness" point - I mean that in a deterministic universe where initial conditions are precisely the same, that the same universe structure will continue to arise and play out over and over again (putting aside quantum uncertainty). While the "ship" may not be the "same" ship, it will still be a ship and not a refrigerator.

[jacknews]

Inflation is mysteriously seemingly the opposite of the very rapid gravitational collapse leading to a black hole, ie inflation is sort of like a white hole.

I tend to think we are a hologram generated from the surface of a black hole, and yes, probably black holes all the way "up".

Of course, it still leaves the question of the first black hole, and why anything at all instead of just nothing.

[zoroaster]

Yup - annoying. The answer seems to be always elusively fractalian; the deeper you go, the deeper it goes.

[lovvtide]

You might be interested in Roger Penrose's ideas about "Conformal Cyclic Cosmology".

As best I understand, he's proposing that the universal will not ever fully collapse into a black hole. On the contrary, it will continue to expand and diffuse, eventually reaching a state in the far future—and here is where the details exceed my understanding—somehow physically/mathematically identical to the conditions that were present at the Big Bang. Or in other words, if you run time out to an infinity in one direction, it sort of "wraps back around" on itself.

https://en.wikipedia.org/wiki/Conformal_cyclic_cosmology

[zoroaster]

This is very interesting - thank you for sending. His "cyclic cosmology" somewhat fits into 2 but with a different flavor. And given you reach a stage of maximum entropy during the heat death of the universe prior to folding back into a new singularity - it seems the same result would still occur each time given no changes in initial conditions.

I'm sort of leaning towards LinuxBender here in thinking this is all some infinite movie on loop generated bc consciousness was bored by itself in the dark.

[cercatrova]

This video about deep time is pretty interesting: https://www.youtube.com/watch?v=uD4izuDMUQA

Melodysheep (the creator) has some great stuff on the topic.

[zoroaster]

Epic - this fits into category 2 with the "big crunch" situation, but the nothingness / heat death of the universe one also seems possible. I think the gravitational pull of a supermassive black hole consisting of all black holes in the universe would probably overwhelm the expansion force and draw everything into it, but who knows.

Very cool - thanks for sending.

[zoroaster]

Hello friends - you'll be very happy to know that Exurb1a recently had a great video addressing some of these points. https://www.youtube.com/watch?v=Jv79l1b-eoI

[aristofun]

You have a basic assumption through your post that any of these events actually took or take place in a straightforward materialistic/mechanistic way.

Whil in reality it’s nothing but purely theoretical mathematical models operating on such a high level of abstraction and uncertainty that it is even hard to decide whether some of your questions make any sense or not.

[zoroaster]

IMO none of this is really operating on a high level of abstraction. We can observe black holes, we can observe that they attract light and matter, etc etc.

That said - I agree w/ the point about whether or not these questions even make sense to ask when we (collectively) ultimately know so little. This is why I wanted to ask it in a public forum in the first place - to test my understanding and to see if there are others I can learn from who might have a more advanced understanding. These aren't exactly questions that people will leap to answer in the office or in daily conversation. That's why I wanted to bring it here, where I feel people are generally more thoughtful and insightful concerning existential topics.

I've appreciated a lot of the links to other resources, and pushback on some of the assertions. They have been and are helpful!

[ttronicm]

Try thinking of the "big bang" as more of phase change where there was something "before" that was not like the "now" at all. A black hole is also a phase change that expands, but we really can't experiment with either deep time or black holes... yet.

[dave333]

Short answer is the Big Bang theory is wrong. Physics has major problems including identity of dark matter and the whole quantum entanglement spooky action at a distance thingy. Mills has proposed a purely classical atomic model that solves molecular structures exactly and also identifies dark matter as hydrinos - hydrogen atoms with the electron in a lower orbit than ground state. Mills predicts an oscillating universe alternating between matter-filled and energy filled which avoids any big bang and also no beginning or end. Latest update from Mills: https://brilliantlightpower.com/december-update-on-our-progr...

[dave333]

The usual instant knee-jerk downvote I see. I wonder what it is in what I wrote that you object to?

[sdwr]

I feel like I need a trigger warning for existential questions.

[zoroaster]

Sorry :(

I feel for you; I wish I had a trigger warning on existential questions this AM too.

[jacknobody]

:) aah, but we're not really trapped; mystical truths are pertinent in everyday life.

[bradwood]

Nope.

It's turtles all the way down.

[zoroaster]

What about the elephants?

[vinnie-io]

the universe just expands, then contracts due to gravity into a single black hole, explodes (big bang), and we start again

[MikeFez]

There's no evidence that this is the case, especially with the knowledge that the rate of expansion is increasing over time: https://en.wikipedia.org/wiki/Accelerating_expansion_of_the_...

[Pietertje]

And this has been going on for ages and we simply are universe X in time.

Alternative hypothesis the OP seems to refer to is the one of Lee Smolin in which a black hole from a previous universe creates a new universe. Smolin wrote a book about his theory, The Life of the Cosmos. I haven't read it nor do I know / understand his theory fully, so interested to learn others viewpoint on this theory.

[zoroaster]

Yes, that was my case (2). Spatiotemporal marble bounded by big bang and expansion edge. But it's not very satisfying - what is outside? Why?

It does align w/ the "eternal recurrence" concept.