Cont: Why James Webb Telescope rewrites/doesn't the laws of Physics/Redshifts (2)

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Puppycow said:
Seems a bit obvious to me, albeit with the benefit of a helping hand from people much smarter than myself.

It’s top-heavy IMF. Why not? The stars in the early universe were not the same size as the stars we see today.

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A solution to the impossible galaxy problem.... which was never a problem to begin with, but now that there's a potential solution maybe there was a problem.
 
Mike Helland said:
A solution to the impossible galaxy problem.... which was never a problem to begin with, but now that there's a potential solution maybe there was a problem.
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No one ever said there wasn't a problem. "Our models of galaxy formation aren't very good, so the problem is probably with those models", and "there's no problem" are pretty different statements. The fact that both statements agree that this problem doesn't impact much on our credence in basic cosmological models doesn't change that.
 
Roboramma said:
No one ever said there wasn't a problem. "Our models of galaxy formation aren't very good, so the problem is probably with those models", and "there's no problem" are pretty different statements. The fact that both statements agree that this problem doesn't impact much on our credence in basic cosmological models doesn't change that.
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I don't think that's something to brag about.

The impossible galaxies have been showing up for 20+ years. The idea is to separate the cosmological model from the galaxy formation models. The only purpose of that mindset is to avoid having to question deeply held beliefs about the beginning of the universe.

On one hand, you have folks denying there's a problem.

On the other hand, you have folks trying to solve the problem.

It's kind of like the CMB cold spot.

On one hand, it's not a big deal. Don't worry about it.

On the other hand, it's evidence for parallel universes.

https://phys.org/news/2017-05-cold-sky-collision-parallel-universe.html

https://phys.org/news/2022-12-supervoid-doesnt-mysterious-cmb-cold.html

Models of galaxy formation work just fine, if you give it more than 1 billion years to make a Milky Way like galaxy. it probably needs more time than just 4 rotations.
 
Mike, you keep pointing out what comes down to the point that observations of early galaxies differing from our galaxy formation models should cause us to update our credence in not just galaxy formation models, but also cosmological models.

That I agree with. But the question is how much? And that depends on the credence we had in our galaxy formation models. That credence wasn't particularly high, so the update with respect to cosmological models also shouldn't be very high.

That's just Bayes' Rule.
 
Mike Helland said:
A solution to the impossible galaxy problem.... which was never a problem to begin with, but now that there's a potential solution maybe there was a problem.
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You seem to be getting confused between galaxy formation models and BBT. The former never contradicted the latter. The latter is so well evidenced that the problem, given the lack of decent data, was always going to be with the former. Now we can see what is going on more clearly, we can look at those galaxy models with some confidence. Previously it was mostly guesswork based on fuzzy Hubble images.

It has been thought for some time that the IMF we were using was quite possibly wrong*. Now it may be that we have evidence to say that is the case.

*See, for instance;

'Generic Spectrum and Ionization Efficiency of a Heavy Initial Mass Function for the First Stars'
Bromm, V., Kudritzki, R. P. & Loeb, A. (2001)
ApJ (free access)

https://iopscience.iop.org/article/10.1086/320549/meta


And I don't know where this 'impossible galaxy' nonsense came from. Probably Lerner. There were some early results from photometric redshift estimates that caused some crackpots to get their knickers in a twist, and a few non-crackpots to jump the gun and get their stuff on arXiv, just in case the observations held up. Well, they didn't hold up.

So, now we have, for instance;

'The chemical enrichment in the early Universe as probed by JWST via direct metallicity measurements at z ∼ 8'
Curti, M. et al (2023)
MNRAS (free access)

https://academic.oup.com/mnras/article/518/1/425/6724253?login=false

in which we learn;

The inferred gas temperatures range from 1.2 104 K to 2.8 104 K, with the Te -based metallicities ranging from extremely metal poor (12 + log(O/H)∼7) to about one third solar.
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Low metallicity is what is expected in the standard model for early galaxies. It is not what is expected in steady-state models (not that there are any left).

and;

The two most ‘massive’ galaxies of the sample at z∼7.6 (log(M⋆/M⊙) = 8.1–8.7)..........
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That is ~ 125-500 million solar masses worth of stars in those galaxies. The Milky Way, iirc, is somewhere north of 10 billion solar masses of stars. Of course, neither of those figures include dark matter, just the stellar masses.

Low mass galaxies are what is expected in the standard model for early galaxies. It is not what is expected in steady-state models (not that there are any left).

So, I would equate the galaxy formation models versus LCDM/ BBT, with the 'neutrino problem' that vexed solar physics until the early 2000s. They had two choices - either the standard solar model was wrong, or our understanding of neutrino physics was wrong. Far more likely that the latter was true, particularly when some (i.e. Pontecorvo) had already suggested neutrinos may have mass. Best to check that before throwing the baby out with the bathwater, eh?
The same applies with the IMFs of early galaxies. Best to check it before throwing out an extremely well-evidenced theory. And that is what is happening now. Sounds like science doing what science is supposed to do to me.
 
Roboramma said:
Mike, you keep pointing out what comes down to the point that observations of early galaxies differing from our galaxy formation models should cause us to update our credence in not just galaxy formation models, but also cosmological models.

That I agree with. But the question is how much? And that depends on the credence we had in our galaxy formation models. That credence wasn't particularly high, so the update with respect to cosmological models also shouldn't be very high.

That's just Bayes' Rule.
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Here's how it looks to me.

We thought our galaxy was about 12 billion years old.

We see galaxies like it very far away. So somehow the galaxy models need to do what they do in 12 billion years, in 5 billion years, or wait, 3 billion years, oh wait, 1 billion years.

Some galaxies are now going back to 350 million years after the big bang.

At what point do we bring out cluestick and start hitting ourselves in the face with it?

Again, here's this:



Do cosmologists have an extremely high confidence in the standard model?

Not really.

Why should we?

it's one thing to say this is a theory about how the universe began. Ok. That's kind of fun.

It's completely different to think that it's certainly real, and that other people should accept it without doubt.
 
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steenkh said:
Nice how you ignored just about everything he wrote.
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The argument is that the early universe looks different than the local universe.

Of course that's true.

That was true 30 years ago when z=4 was the early universe too.

It's kind of like people that see that the rapture didn't happen, and then go on believing it's still coming up. Those people don't have a hard-coded time limit for their event though. Their belief was always weird. But a consistent level of weird.

Belief in the big bang just keeps getting weirder.

If we plot all the galaxies we have data for on a timeline of the present back to the big bang, whether it's size, or metallicity, well, it'd just be a black graph because there's like, millions of them.

Ultimately I think you'll find galaxies are smaller and larger, and higher and lower, at all distances, than our galaxy, up to the edges of the range that we can observe. At the edge of our observable range with current technology we face the same selection/observation bias we always face: the farthest observable galaxies are the easiest to observe among their population.
 
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Mike Helland said:
If we plot all the galaxies we have data for on a timeline of the present back to the big bang, whether it's size, or metallicity, well, it'd just be a black graph because there's like, millions of them.

Ultimately I think you'll find galaxies are smaller and larger, and higher and lower, at all distances, than our galaxy, up to the edges of the range that we can observe. At the edge of our observable range with current technology we face the same selection/observation bias we always face: the farthest observable galaxies are the easiest to observe among their population.
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You prefer to ignore contrary arguments, because you are in any case dismissing them with a hand wave?

For instance, that as more distant galaxies are spectroscopically examined, they are found to have lower metallicity. As expected. How are you explaining that away with selection bias? We also find that they are smaller, contrary to what is expected by selection bias.
 
Mike Helland said:
Ultimately I think you'll find galaxies are smaller and larger, and higher and lower, at all distances, than our galaxy, up to the edges of the range that we can observe. At the edge of our observable range with current technology we face the same selection/observation bias we always face: the farthest observable galaxies are the easiest to observe among their population.
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If it was selection bias, then the furthest galaxies we see should be the easiest to see. i.e. the most luminous/ massive. And the ones we are seeing are less massive by some distance than local ones, and have lower metallicity. Precisely as expected by the standard model, and not as expected by non-existent steady-state models. In other words, the ones we can't see must, by definition, be even less massive.

There is a reason that the vast majority of very smart scientists dumped SS models long before we even launched COBE. It is called evidence. And it favoured one model and falsified the other. I'll let you figure out which one was which!
There is a reason that very smart scientists accepted an accelerating expansion of the universe more recently. Something that was not part of the standard model. Again, it is what the evidence told us.
And that is where SS models fail - complete lack of evidence. The few people that hold onto those models these days, seem to do so based purely on faith. And that isn't science.
 
Mike Helland said:
The argument is that the early universe looks different than the local universe.

Of course that's true.
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Ultimately I think you'll find galaxies are smaller and larger, and higher and lower, at all distances, than our galaxy, up to the edges of the range that we can observe.
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Surely you have just contradicted yourself? Either it looks different, or it doesn't. SS models say it should look the same at all distances, which is what your second statement says. However, it doesn't look the same, as your first statement says. ???????
 
jonesdave116 said:
There is a reason that the vast majority of very smart scientists dumped SS models long before we even launched COBE.
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Reference to very smart scientists don’t work because here we are dealing with a very smart person who has seen a simple solution that the vast majority of very smart scientists have never noticed :p
 
jonesdave116 said:
Surely you have just contradicted yourself?
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Don't think so.

Either it looks different, or it doesn't. SS models say it should look the same at all distances, which is what your second statement says. However, it doesn't look the same, as your first statement says. ???????
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Steady state models are expanding models and no one here is advocating them.

The universe has always looked different at the edge of our technology's ability to observe it. And it always turns out not to be.
 
Mike Helland said:
The universe has always looked different at the edge of our technology's ability to observe it. And it always turns out not to be.
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Multiple times, people have pointed out hard data showing significant observed differences between earlier universe and today. When you claim there's no difference, you're lying.

You aren't just some naive amateur who is skeptical of our understanding. You're a crackpot.
 
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