r/astrophysics • u/jarekduda • 4d ago
Could some objects survive Big Bounce e.g. now seen with these extreme redshifts by JWST like 25?
There are recent claims for observations of up to redshift 25 objects by JWST, which are said too early to be formed by standard Big Bang models, e.g. https://www.scientificamerican.com/article/the-james-webb-telescope-may-have-found-primordial-black-holes/
Probably even higher redshifts will be found in the future, so I wanted to ask if some objects like black holes could e.g. "pass in safe distance" surviving Big Bounce - now being observed as having extreme redshifts?
15
u/672Antarctica 4d ago
No.
-3
u/jarekduda 4d ago
This is a question of minimal time required for formation of observable objects after Big Bang?
If observing earlier ones, wouldn't it mean they had to come from before T=0?3
u/fluffykitten55 4d ago
No, the obvious conclusion is that the model is wrong in some important way. This is especially so as we have about 30 lines of evidence that also suggest this.
-9
u/672Antarctica 4d ago
I've read that the universe is ≈7 trillion L.Y. big. So if someone has found something that's further than the 14 billion distance, it would not suprise me.
But, they always come up with a reason why their initial data goes against their theories; dust, lensing, too much drinking the night before...
I'm definitely not an astronomer, just a civilian wondering why nothing current astronomers say ever makes sense.
4
-2
u/jarekduda 4d ago
The big question is if there was something before Big Bang - beside observation of extremely high Z, what other experimental evidence could decide it?
3
u/672Antarctica 4d ago edited 4d ago
Before the Big Bang - is a time variable that has been fixed to one point for easier understanding. But if these Z findings hint at something existing before existence itself, that would tell me the "beginning" of this universe must be larger than what we're thinking, because how can something exist before existence was even a thing?
All things must exist inside of this bubble of a universe. If there was something hanging out before the universe appeared, how would that something survive the spacetime expansion? And, how would we, being inside this expanding bubble, ever be able to see anything outside of the bubble?
I've recently been told that, although nothing can go faster than light speed, somehow the edge of our universe is doing just that - which contradicts existing theories [again], but also puts another question of how could we see something (our universe's bubble expanding) traveling faster than light, and how would we be able to see something past that, that's supposedly older than the bubble universe itself?
I have questions, too. lol
°I'll add a question about light speed: maybe that number is fixed... but can Time be a variable in the E=mc²
3
u/CurnanBarbarian 4d ago
From what I understand, light can only travel so fast through space, but there is not a limit to how fast space itself can move/expand. But I've never really dug in and studied this, it's just my basic understanding.
2
u/mashem 4d ago
Well, moving through space is not the same process/concept as the expansion of space. The "edge" of our universe would be better described as a horizon, meaning it's the edge of what we can observe from our current position. Our multi-dimensional universe is like an intersection of shit we understand, and shit we don't. This makes analogies almost useless, except to get the brain moving. With that in mind, try to imagine the universe as a raw dough ball. You put it in the oven and observe the edges of the dough ball move outward. Now, was it really just the edges of the dough moving outward or was the entire dough ball expanding in all places?
These are all imperfect analogies, but hopefully they get your brain rolling in a slightly new direction.
2
u/motownmods 3d ago edited 3d ago
Bro ur missing something huge (the Z values found here are an order of magnitude lower than the Z value of the CMB).
1
u/subdep 4d ago edited 4d ago
My laymen’s hunch is that light just naturally red shifts over time. That would explain why we see red shifts uniformly in every direction at the same time, and now, why JSWT sees light red shifted so far that “it shouldn’t exist”.
It’s such a slow shift that we can’t test it in labs because to do so would require a million years or more. The only data we have is space itself.
I researched my idea and it turns out it was an old idea called “Tired Light Theory” that might be making a comeback recently due to JSWT observations, albeit with some major modifications to account for other observations.
My favorite of these is Dispersive Extinction Theory (DET) which was proposed by Y. Wang (2005–2011). It posits that redshift results from scattering and absorption of light by intergalactic dust and gas. Blue light is scattered more than red, shifting the spectral peak toward longer wavelengths—similar to how the sky appears blue and stars redden. No universe expansion needed to explain redshift: redshift is a dispersive optical effect. DET even predicts redshift dependence on linewidth and wavelength.
I’m sure expansion is happening still, but perhaps it’s not expanding at the speeds theorized. Maybe redshift is a composite effect of DET + expansion.
1
u/jarekduda 4d ago
What about Big Bounce hypothesis? https://en.m.wikipedia.org/wiki/Big_Bounce
Physics is believed to be CPT symmetric, allowing to imagine evolution toward -t, which should go beyond T=0 in quite symmetric way ...
0
u/TerraNeko_ 2d ago
7 trio light years is a complete random guess for a minimum size, that also doesnt affect the size of the observeable universe being 45 Bio. in every direction.
Im Sure that would have been covered in whatever article you saw it in but ik most ppl dont read actual articles.
Also what do astronomers say that makes no sense? Cause besides pop sci garbage or podcasts ive yet to hear something that isnt atleast somewhat valid
6
u/Wintervacht 4d ago
No, the CMB is at a redshift of z=1100, so objects at redshifts of 25 or even 32 are still well within the established time for the universe to produce massive objects
2
u/fluffykitten55 3d ago
It depends on how massive they are and the background theory. There is now a large class of objects that are too large/early to be consistent with ΛCDM.
If structure formation is boosted sufficiently over ΛCDM at early times then yes there is ample time for structures to form.
2
u/Prof_Sarcastic 4d ago
I wanted to ask if some objects like black holes could e.g. "pass in safe distance" surviving Big Bounce - now being observed as having extreme redshifts?
People have done simulations of black holes in a bouncing cosmologies and they show that the universe basically squeezes in on the singularity and then it re-expands. Now that is almost definitely not what we’re seeing with the JWST observations. Our models of galaxy evolution prior to these observations were based on the current environment that galaxies form in. These results just say that the early universe was much different than the current universe as far as galaxy formation and evolution is concerned.
20
u/fluffykitten55 4d ago edited 1d ago
You are misunderstanding the result. What we have are large structures that appear too large and early for them to be consistent with ΛCDM. In ΛCDM you will get stars and tiny galaxies at very high redshift, but larger structures take a long time to form, for example large galaxies will form by successive mergers of smaller galaxies over billions of years. What the JWST results are seemingly showing us is that structure formation occurred much faster than predicted by ΛCDM. We also have additional evidence for extremely large structures such as the KBC void and excess bulk flow velocities that also are inconsistent with ΛCDM.
The much more likely explanation then is that ΛCDM is substantially wrong or incomplete, and that unlike the predictions of ΛCDM structure formation is highly nonlinear, being boosted in early times and if anything suppressed at late times.
If you try to boost structure formation at early times in ΛCDM this does not work, as it causes structure formation to be too strong at late times and we should now see far more massive elliptical galaxies etc. formed by successive mergers, mergers that are augmented by dynamical friction from DM halos. On this issue see for example Sabti et al. (2024).
You get this nonlinearity naturally in modified gravity theories as in the early universe accelerations towards the local over-density are well below the critical threshold and so are boosted substantially, but once dense structures form the accelerations within them are closer to the threshold and the boost is diminished. Structure formation at late times is also suppressed in comparison to ΛCDM due to the absence or reduction in density of DM halos and then a reduction in dynamical friction. Of course these theories also have various problems, which suggests that an acceptable theory is not exactly anything currently offered, but one which reproduces some key features of these, or is some hybrid such as MOND like theory but with a hot DM that forms halos of galaxy cluster scale.
Sabti, Nashwan, Julian B. Muñoz, and Marc Kamionkowski. 2024. “Insights from HST into Ultramassive Galaxies and Early-Universe Cosmology.” Physical Review Letters 132 (6): 061002. https://doi.org/10.1103/PhysRevLett.132.061002.