this post was submitted on 27 Apr 2025
312 points (99.7% liked)

science

18200 readers
556 users here now

A community to post scientific articles, news, and civil discussion.

rule #1: be kind

founded 2 years ago
MODERATORS
you are viewing a single comment's thread
view the rest of the comments
[–] [email protected] 28 points 1 day ago* (last edited 22 hours ago) (6 children)

If that is true maybe that means that it actually is finite and has a center. And the rotation and light speed put an upper bound on its size.

Then again the expansion of space doesn't care about such mundane things as a cosmic speed limit so the universe rotation probably won't either. Or the extents just slow down.

[–] [email protected] 0 points 6 hours ago (1 children)

If that is true maybe that means that it actually is finite and has a center. And the rotation and light speed put an upper bound on its size.

Actually no, that would only be true if the universe was two-dimensional. The universe essentially curves back on itself. Kurzgesagt explained the two options of finite and infinity universes and this timestamp explaines the curving back: https://youtu.be/isdLel273rQ?t=120

[–] [email protected] 4 points 5 hours ago

Kurzgesagt really like to present scientific speculations as fact.

We simply do not know whether the universe is finite or infinite. And so far no curvature has been observed. As far as we are aware it is flat.

[–] [email protected] 19 points 22 hours ago (2 children)

I think that if space itself is what is rotating, then speed of light limit does not apply. But if it's everything in the universe orbiting, as it were, a central point, then it would.

But if it is space itself rotating, then that would suggest some objective frame of reference outside the universe. Wouldn't it?

[–] [email protected] 2 points 5 hours ago (1 children)

But if it is space itself rotating, then that would suggest some objective frame of reference outside the universe. Wouldn't it?

Not necessarily. Just like space is growing without the need for an objective outside frame of reference, it could be rotating - the rotation is just relative to itself.

[–] [email protected] 1 points 5 hours ago (1 children)

I don't think something can rotate relevant to itself. If all of reality was the earth, and nothing else, how can you tell if it's spinning or not?

Please use small words if you try to answer this. I know a decent bit of applied physics, but once it turns to pure math, my head starts to swim.

[–] [email protected] 1 points 4 hours ago

Stuff could move around differently. Rotations have many effects, e.g. rotation curves (the closer you are to the center of the rotation, the faster you go). We could still figure out that the earth is rotating by measuring the effects a rotation has.

[–] [email protected] 4 points 20 hours ago* (last edited 20 hours ago)
[–] [email protected] 23 points 23 hours ago (3 children)

And if everything is rotating, and most is rotating in the same direction, it means we're probably in a black hole.

Science is going to be interesting during the next twenty years.

[–] [email protected] 1 points 5 hours ago

Why would it mean that? And how can we be inside a black hole when we are not spaghettified?

[–] [email protected] 20 points 23 hours ago (1 children)

Black hole cosmology makes the most sense to me. But what do I know, I’m just a burnt out stoner.

[–] [email protected] 1 points 22 hours ago* (last edited 22 hours ago) (1 children)

If we're a "white hole" I guess it must've been one insanely gigantic object that collapsed with no other matter around it rendering it dormant.

Unless somebody knows why we wouldn't see new violently hot matter the higher universe black hole is consuming spewing out into our universe if it were still active.

Where would it spew? There's no center as I understand? Psyduck holding head

[–] Nomecks 4 points 18 hours ago

It may have started consuming more matter billions of years later and the light hasn't reached us yet/will never reach us

[–] [email protected] 6 points 23 hours ago (1 children)

Why would it mean that?

I'm honestly curious.

[–] [email protected] 27 points 23 hours ago* (last edited 23 hours ago) (7 children)

I'm completely a layman, so don't take my word as fact. But currently there's a trend in thinking that because more than half of the galaxies they've been measured all rotate the same direction (as opposed to all random directions that a uniform static bang should result in) then the universe started out spinning in that direction.

What starts from a very small condensed state, and expands rapidly while spinning in one direction? Black holes.

Black holes also go through a life cycle that's pretty close to what we expect or universe to go through.

It's a new thought, I'm not even sure how much evidence there is past the galaxyspinning evidence. But it's interesting and has scientists thinking.

It also takes care of any "multiverse" questions, since black holes are already in a universe. Some of the holes could be pocket universes, and we could be in one, with black hole pocket universes of our own.

[–] [email protected] 0 points 6 hours ago* (last edited 6 hours ago)

The observable universe is also way denser than a black hole of equivelent radius (black holes get lower in density the bigger they get) so one way or another we are in a black hole in the sense that somewhere out there is an event horizon through which you can never leave, just not in the traditional understanding which only really applies to 'small' (every single other) black holes.

[–] [email protected] 13 points 22 hours ago* (last edited 22 hours ago) (1 children)

It's just pocket universes all the way down.

[–] [email protected] 13 points 22 hours ago

And up maybe too.

[–] [email protected] 11 points 22 hours ago (1 children)

I'm a layman, too, so take everything with a grain of salt.

As for evidence, if I both understood and remember correctly, the maximum distance we can actually see something (Hubble radius) just happens to align quite nicely with the Schwarzschild radius, a parameter based on the mass of a black hole, which correlates to its radius. They have to be identical for this theory to be true. Them almost being so could be a coincidence, though.

In addition, from our perspective, there's no real difference between an expanding universe and one with shrinking particles. If the planck length actually shrinks, to us, it will seem like everything else will move away. Within the last 100 years, multiple people created some models for that, proving how it could work while leaving physics as we observe them intact.

A proof could be found by observing a white hole, the opposite of a black hole. A space you cannot possibly enter, ejecting energy. Think of it as the stuff entering the black hole from the outside, as oberserved from the inside. They are just a theory for now.

Once again, I've got not actual clue and you might want to dive into that rabbit hole yourself. It's fun in here.

[–] [email protected] 3 points 21 hours ago

Now that you mention it, i forgot about the radius possibility. Thanks for the follow-up!

[–] [email protected] 5 points 19 hours ago (1 children)

I’m not even sure how much evidence there is past the galaxyspinning evidence

There was another article posted recently I can't find now, that talked about the discrepancy between the age of the universe based on the Hubble constant, and what's observed of the CMB, or something like that. Apparently that discrepancy can be resolved if the universe itself is rotating.

Really hoping someone can track it down and post up a link, I'm probably making hash of the actual article...

[–] [email protected] 3 points 17 hours ago

I remember that too now. Pretty neat stuff.

[–] [email protected] 3 points 22 hours ago (1 children)

Would our universe need to behave like anything inside our universe though? It could be a rotating expanding universe without being a black hole

[–] [email protected] 10 points 22 hours ago (1 children)

The goal here is to make probable inferences, not to avoid being wrong at any cost. There's always more possibilities, but we should try to eliminate the likely-seeming ones before chasing down less-likely ones. Know what I mean?

The possibilities are as vast as our ignorance: greater than we have the means to measure by some indescribably large margin.

[–] [email protected] 4 points 21 hours ago (1 children)
[–] [email protected] 3 points 19 hours ago

Thanks.

Science means a lot to me

[–] [email protected] 2 points 20 hours ago (1 children)

Ive never heard of black holes suddenly expanding. Everything ive read js that they just very, very, very slowly dissipate through Schwartzchild radiation.

[–] [email protected] 3 points 19 hours ago (1 children)

They expand if they have matter falling into them.

[–] [email protected] 0 points 15 hours ago* (last edited 14 hours ago) (1 children)

What's the "they" that you mean? The event horizon, the transition point where light can't escape?

That doesn't sound like what they were saying. The actual "hole" supposedly remains infinitely small. And the event horizon radius would expand at a pretty slow rate as matter fell into the black hole. Exponentially smaller as it gains mass.

So I'm still trying to understand in what case a black hole ever "expands rapidly".

[–] [email protected] 1 points 4 hours ago (1 children)

Dude, everyone here has said they're not experts. Idk what you're expecting us to say.

[–] [email protected] 0 points 3 hours ago* (last edited 3 hours ago) (1 children)

Dude, I'm expecting the most basic explanation of what someone meant by something they said. Claiming not to be an expert isn't a good response when someone asks wtf you meant

You said

What starts from a very small condensed state, and expands rapidly while spinning in one direction? Black holes.

I'm asking where you got that from, since it's the opposite of anything ive ever heard about black holes and what almost anyone thinks about black holes.

[–] [email protected] 1 points 1 hour ago* (last edited 1 hour ago)

Look it up lol I have no idea. I told you im just a layman, same with everyone else.

You're demanding answers on the Internet, a place that holds all of humanities knowledge in your hand. Use it and come back with your findings so we can all learn more.

[–] [email protected] 2 points 23 hours ago (1 children)

Smarty pants. I don't find any issues with your thought ~~prices~~, process but I'm a layperson.

[–] [email protected] 2 points 21 hours ago (1 children)

My thoughts are only worth a penny. Or so I've been told.

[–] [email protected] 1 points 21 hours ago

Rofl. Corrected autocorrect.

[–] [email protected] 3 points 22 hours ago

I believe just the observable part is. Could be more.

[–] [email protected] 3 points 22 hours ago

Wow, so maybe the universe really is centered around me after all. Take that, 1st grade teacher! j/k.

[–] [email protected] 1 points 21 hours ago (2 children)

I thought the general consensus was that it IS finite and has a relative center point?

[–] [email protected] 1 points 5 hours ago

No, the general consensus is that it seems to be infinite and has no relative center point.

[–] [email protected] 5 points 20 hours ago

Nah in the past it looked like a pretty homogeneous mass when zoomed out enough. I assume this center of rotation is no more of a "pure center of the universe" than our sun is.

I'd imagine its just a local maximum for gravity.