What is your argument against this?

[Johnny Blade]

.

[Johnny Blade]

Here's a very good introductory video to one of the problems:

Yeah I've already seen it Rumraket. I watch videos like this on a regular basis. I don't understand why you posted this.

Extremely succinct: To derive the conclusion that a distant galaxy "shouldn't exist" requires a model of galaxy formation we can't directly experimentally test. That means some of the values in the model must be assumed (we simply do not know the true values of certain parameters, so a SIMPLIFYING ASSUMPTION is made in many cases). But invariably some of those assumptions turn out to be wrong. So we end up in a situation where we observe something that a particular model with a particular assumption says can't exist, which is often times really just evidence that one or more of the ASSUMED parameters in the model are off.

This is very likely to be the case with our models of the earliest stars and galaxies to form. The parameter known as the Initial Mass Function (IMF) that strongly affects the rate of star formation was assumed to be constant across the universe in many models typically applied by astrophysicists, but in fact other models exist that suggest this assumption could be untrue, and that for example the IMF could depend partially on temperature (among other things). The early universe is thought to have been hotter than it is now, which gives us reason to think the assumption of a constant IMF is wrong when we get close to the big bang.
Yet for a long time astrophysicists proceeded with the assumption of a constant IMF because doing the calculations were easier and simpler, and we did not have observational data at the time that implied the model was too unreliable.

This has now changed. The newest generations of telescopes can now see so far back in time we are in a situation where we can observationally test the validity of the assumptions made for early-universe star and galaxy formation, and it looks like they will need to adjust the models.

And?

Notice how NOTHING, N O T H I N G I've just explained can be found in the popular science press. A press which just likes to tell stories about drama, paradigm shifts, "impossible results", and "textbooks have to be rewritten" because it grabs attention and generates clicks and ad-revenue. But in reality science is just way more complex than that.

And then the universe magically gets older and older? I don't understand what your point is. Rumraket. I was just pointing out that we don't seem to have a good way of determining the age of galaxies. You said that we do, because of spectrum analysis that indicate the heavy element contents of galaxies.

If we end up with data showing that only low or nonmetallic(metallic meaning heavy elements) exist in the far away galaxies, then I would agree with you! Do you have anything that shows this to be true?

[Rumraket]

Here's a very good introductory video to one of the problems:

Yeah I've already seen it Rumraket. I watch videos like this on a regular basis. I don't understand why you posted this.

I posted it because your posts give the impression you are completely unaware of how any of this works. Excessively simplistic, dichotomous thinking. You seem to think, for example, that linking popular-press articles is a reliable method of reporting the results of scientific observations and experiments. It is nothing of the sort. The popular press feeds off sensationalization, drama, and other forms of attention-grabbing techniques. One of the most common, at least when it comes to reporting on scientific developments, is to exaggerate the extend to which a new discovery contradicts what we already know, or is "surprising" to the scientists in the field. Sadly, and often, scientists themselves are entirely complicit in hyping their results in this way. The incentives are all to well-known. They want to advance their careers, they want to draw attention to the institutions they work for, and so on.

In actual reality, on any scientific topic, there is a range of models that for a large range of observations are indistinguishable, and for whatever reason one of these models has fallen into more general use over other similar models(often because it's just easier to work with, such as models with the constant IMF). Another factor is that models typically make statistical predictions, with phenomena spanning a range of values given certain probabilities. Most things (such as stellar mass, say) is going to fall in some range with the majority of stars clustering around some range, and then with lower probability but not actually impossible according to the model, there will be stars that fall outside the most common range.

Then when new technology is invented and the boundaries for observation are pushed, we get into an area where some of the models fail. Either some of the lower probability events turn out to be more frequent, or some of the assumptions turn out to have been too simplistic. Some times this includes the most popular model. These nuances are completely lost with popular pres science reporting. They take "is quite rare in most models but we observed one" or "they appear more frequently than the most popular models predicted" to mean "shouldn't exist" and "everyone's heads exploded with surprise when we saw the result" leaving the impression that nobody knows nothing and you can't trust anything and everything's guesswork, nobody has a clue, it all is impossible, textbooks need to be rewritten, there's a crisis in the field, bla bla bla bla.

The articles you link are of this form. They have misled you and it's apparent from your posts.

Extremely succinct: To derive the conclusion that a distant galaxy "shouldn't exist" requires a model of galaxy formation we can't directly experimentally test. That means some of the values in the model must be assumed (we simply do not know the true values of certain parameters, so a SIMPLIFYING ASSUMPTION is made in many cases). But invariably some of those assumptions turn out to be wrong. So we end up in a situation where we observe something that a particular model with a particular assumption says can't exist, which is often times really just evidence that one or more of the ASSUMED parameters in the model are off.

This is very likely to be the case with our models of the earliest stars and galaxies to form. The parameter known as the Initial Mass Function (IMF) that strongly affects the rate of star formation was assumed to be constant across the universe in many models typically applied by astrophysicists, but in fact other models exist that suggest this assumption could be untrue, and that for example the IMF could depend partially on temperature (among other things). The early universe is thought to have been hotter than it is now, which gives us reason to think the assumption of a constant IMF is wrong when we get close to the big bang.
Yet for a long time astrophysicists proceeded with the assumption of a constant IMF because doing the calculations were easier and simpler, and we did not have observational data at the time that implied the model was too unreliable.

This has now changed. The newest generations of telescopes can now see so far back in time we are in a situation where we can observationally test the validity of the assumptions made for early-universe star and galaxy formation, and it looks like they will need to adjust the models.

And?

So the articles you link are shitty science reporting that exaggerate, and you are being misled by the silly focus on drama, sensation, and expressed surprise by scientists being quoted, seemingly because you don't really understand the real work behind the scenes that actually make these findings much less surprising or field-overturning than they would have you believe. So in fact, you do NOT have a good reason for thinking we don't have good methods for establishing age or distance to galaxies. It's an impression you've got from bad reporting, and probably from apologists exploiting the bad reporting.

Notice how NOTHING, N O T H I N G I've just explained can be found in the popular science press. A press which just likes to tell stories about drama, paradigm shifts, "impossible results", and "textbooks have to be rewritten" because it grabs attention and generates clicks and ad-revenue. But in reality science is just way more complex than that.


And then the universe magically gets older and older?

No. The universe didn't get older, magically or otherwise. The rate of star formation (and therefore rate of galaxy evolution) at the earliest times was increased. The universe's age remains unchanged.

I don't understand what your point is. Rumraket. I was just pointing out that we don't seem to have a good way of determining the age of galaxies. You said that we do, because of spectrum analysis that indicate the heavy element contents of galaxies.

If we end up with data showing that only low or nonmetallic(metallic meaning heavy elements) exist in the far away galaxies, then I would agree with you! Do you have anything that shows this to be true?

Yes.

[Rumraket]

They say a picture is worth a thousand words, so here's a drawing meant to be an analogy to what is going on in cosmology with models and observations star and galaxy formation in the early universe:

Model vs reality.png (30.53 KiB) Viewed 1049 times

[Johnny Blade]

If we end up with data showing that only low or nonmetallic(metallic meaning heavy elements) exist in the far away galaxies, then I would agree with you! Do you have anything that shows this to be true?

Yes.

THANK YOU! I will have a look at it and get back to you.

[Johnny Blade]

This might take a while.

BTW: For anyone who is interested, one thing that is cool is that, is that whenever a scientist includes his email address on a paper, they always try to write you back if you have any questions about it.

[Johnny Blade]

If we end up with data showing that only low or nonmetallic(metallic meaning heavy elements) exist in the far away galaxies, then I would agree with you! Do you have anything that shows this to be true?

Yes.

When I say low I mean low as indicating a trend in metallicity that would prove it to be good way to determine the age of a galaxy, as the standard model of cosmology requires it to be.

Not low as in the same kind of lowness we find in nearby galaxies. I had hoped I would have time go through and produce some sort of graphic that would show you what I am talking about. This turned out to be much more difficult than I expected, due to the many different ways metallicity is expressed. And the seemingly arbitrary (at least to me) and difficult to remember names galaxies are given. Plus I am very dumb creationist. That makes me extra dumb. Thankfully I found that someone had already sorta already done this. Here https://mikehelland.github.io/hubbles-l ... licity.htm

[Johnny Blade]

GS-z12(beagle) is actually one of the 4 galaxies in the paper you gave me. GS-z12 (DLA) I believe is referenced in one of the papers I gave you. It's shown here as being low metal (meaning lower than the sun) because all of the galaxies in this chart are measured in metallicity in terms of oxygen abundance and not carbon.

Do you still believe there is a downwards trend in metallicty and high redshift? Do you still believe metallicity is a good way to determine age? Do you see any correlalation between redshift and metallicity here that indicates that any of these galaxies evolved?

[Rumraket]

GS-z12(beagle) is actually one of the 4 galaxies in the paper you gave me. GS-z12 (DLA) I believe is referenced in one of the papers I gave you. It's shown here as being low metal (meaning lower than the sun) because all of the galaxies in this chart are measured in metallicity in terms of oxygen abundance and not carbon.

Do you still believe there is a downwards trend in metallicty and high redshift?

That looks like a clear downward trend to me, yes. Especially for redshifts over 8(Edit: older than 8 billion years, redshifts over 1, I misread the figure). There's a strange lack of measurements over 8 (Edit: billion years)though, not sure why. The magenta boxes seem to just cut off suddenly.

I notice that you've clicked off the 2021 study showing a downward trend over the last 11 billion years. (the grey ones included here:

Skærmbillede 2024-08-03 135402.png (104.35 KiB) Viewed 491 times

There's a lot of uncertainty due to different methods, and another problem is the mass class also strongly affects metallicity. Ideally we'd want to tr ack metallicity with redshift for a specific galaxy mass class. They do this in Zahid et al. 2021:

Skærmbillede 2024-08-03 135747.png (66.09 KiB) Viewed 491 times

Notice the mass-metallicity relation decreases obviously with redshift. The blue curve is redshift z=0.08, yellow curve (which is below blue) z=0.29, and so on, with the red curve (highest redshift) also showing lowest metallicities. So yes, there's a clear and obvious correlation when controlling for the mass-metallicity relation.

Yes, there's a mass-metallicity relation too, in addition to a redshift-metallicity relation. You need to control for mass, which the website you linked doesn't do.

Do you still believe metallicity is a good way to determine age?

I would say there's an obvious correlation for specific mass classes, yes.

Do you see any correlalation between redshift and metallicity here that indicates that any of these galaxies evolved?

Definitely yes.

[Rumraket]

Another independent confirmation of galaxy distance is angular size and morphology. Again when controlling for mass classes, galaxy angular size and morphology changes with increasing redshift. The further away we get, the smaller galaxies get in terms of angular size (indicating they really are further away), and as a proportion of total galaxies, a greater and greater fraction of them consist of smaller irregular-shaped galaxies such as strange ovals (as opposed to neat spirals).

Things appear smaller(has a smaller angular diameter) when further away. The higher the redshift of a galaxy, the trend is for it to also have a smaller angular size.

Galaxy shape evolution also changes with time. The higher the redshift, the higher the proportion of total galaxies appear to me made up of galaxies with smaller absolute size and more irregular shapes.

Yes, the evidence really shows that the universe has changed with time. Sorry.

I'll go find the figures and post them.

[Johnny Blade]

There's a lot of uncertainty due to different methods, and another problem is the mass class also strongly affects metallicity. Ideally we'd want to tr ack metallicity with redshift for a specific galaxy mass class. They do this in Zahid et al. 2021:

That makes sense but hasn't the JWST pointed out huge discrepencies in what we thought was the correct way to determine mass at high redshift? Is mass the same thing as size in astronomy?

Oh well. I'll just go with what you say. Looks like you might be more right than I am.



Yaaay Rumraket! You're the winner!

[Johnny Blade]

Yes, the evidence really shows that the universe has changed with time. Sorry.

I'll go find the figures and post them.

Alright. Make sure they are easy figures.

[The_Metatron]

There's a lot of uncertainty due to different methods, and another problem is the mass class also strongly affects metallicity. Ideally we'd want to tr ack metallicity with redshift for a specific galaxy mass class. They do this in Zahid et al. 2021:

That makes sense but hasn't the JWST pointed out huge discrepencies in what we thought was the correct way to determine mass at high redshift? Is mass the same thing as size in astronomy?

Oh well. I'll just go with what you say. Looks like you might be more right than I am.



Yaaay Rumraket! You're the winner!

You aren’t very good at this insult thing.

By posting that photo, you’ve implied that the goofy kid getting a prize for existing is Rumraket.

Which of course means you just got schooled by the goofy kid.

[Johnny Blade]

Ok!

[Rumraket]

There's a lot of uncertainty due to different methods, and another problem is the mass class also strongly affects metallicity. Ideally we'd want to tr ack metallicity with redshift for a specific galaxy mass class. They do this in Zahid et al. 2021:

That makes sense but hasn't the JWST pointed out huge discrepencies in what we thought was the correct way to determine mass at high redshift?

Haven't heard of that.

Is mass the same thing as size in astronomy?

No. Though there'd be a correlation of that too of course (a bigger star with a higher diameter on average probably also has more mass, say), which you'd have to control for also. But of course objects can have different densities, so a very compact galaxy with a smaller diameter could have a higher total mass than a more "spread out" one that has a greater diameter. And different galaxies could have different stellar populations, such that a galaxy with a higher fraction of younger supergiant stars might have a different total mass than a galaxy of equal apparent size(or equal number of stars) with a higher fraction of old white dwarves or whatever, etc. etc.

All of these factors are things astronomers and cosmologists try to understand and control for of course.

Oh well. I'll just go with what you say. Looks like you might be more right than I am.
(snipped picture)
Yaaay Rumraket! You're the winner!

Thanks, I guess.

[Rumraket]

Anyway here's a nice (though rather technical) website showing a lot of what is known about changes in galaxy evolution over cosmic time:
https://ned.ipac.caltech.edu/level5/Mar ... tents.html

Sadly the website is a bit dated, and the JWST is sure to push on the boundaries of a lot of the models currently posited to explain these trends. But there's a difference between saying the JWST discoveries skewer some of the trends (they might be steeper or flatter than predicted by certain models), as opposed to saying the JWST says we DON'T KNOW NUFFIN.

"The curve is flatter at the beginning and steeper at very early times than the most popular model currently used would have predicted" just doesn't make for a catchy and click-generating headline.

[Johnny Blade]

Anyway here's a nice (though rather technical) website showing a lot of what is known about changes in galaxy evolution over cosmic time:
https://ned.ipac.caltech.edu/level5/Mar ... tents.html

Sadly the website is a bit dated, and the JWST is sure to push on the boundaries of a lot of the models currently posited to explain these trends. But there's a difference between saying the JWST discoveries skewer some of the trends (they might be steeper or flatter than predicted by certain models), as opposed to saying the JWST says we DON'T KNOW NUFFIN.

"The curve is flatter at the beginning and steeper at very early times than the most popular model currently used would have predicted" just doesn't make for a catchy and click-generating headline.

Alright I'll take a good look at everything you have posted when I can. Thank you Rumraket for your time.

[Rumraket]

Another thing worth noting here: The scale on the Y-axis of the metallicity figures(both from the papers and the website you linked) is logarithmic (12+log(O/H). The magnitude of difference between the lower and higher values is actually enormous, spanning hundred to thousand-fold differences in the Oxygen-to-Hydrogen ratio.

By taking the log of O/H and adding 12 to the ratio just makes the values more manageable, but with the unintended consequence of reducing the slope on the curve from lower to higher redshift, inadvertently making it look like the decrease in metallicity is only very slight. While in fact a difference between a metallicity of say 8.5 and 8.7 corresponds to a drop of metallicity of 60%.

[Johnny Blade]

By taking the log of O/H and adding 12 to the ratio just makes the values more manageable, but with the unintended consequence of reducing the slope on the curve from lower to higher redshift, inadvertently making it look like the decrease in metallicity is only very slight. While in fact a difference between a metallicity of say 8.5 and 8.7 corresponds to a drop of metallicity of 60%.

Right they increase the values to make them easier to deal with and then it affects the graph. I should have thought of that. Good for pointing that out.

[Johnny Blade]

I'll get it right one of these days Rumraket. I promise.