JWST and Large Distant Galaxies

I found one here with a bit of googling:

Scroll down to section “4.2. Size and Profile Shape Evolution” and we find this:

4.2. Size and Profile Shape Evolution

One of the most important findings in galaxy evolution studies in the past decade has been the discovery that distant galaxies are more compact than systems of the same mass in the local universe (e.g., Daddi et al. 2005; Trujillo et al. 2007; Buitrago et al. 2008; van Dokkum et al. 2008, 2010; Weinzirl et al. 2011; Baro et al. 2013; Williams et al. 2014).

This change in sizes with time is now well characterized, and the evolution of galaxy sizes at a constant stellar mass selection of M* > 1011 M⊙ can be characterized by a power law of the form R e ~ α (1 + z)β. The value of the power-law slope changes with the galaxy surface brightness type, such that the disk-like galaxies with Sérsic indices n < 2.5 evolve with β = -0.82 ± 0.03, while spheroid-like galaxies with n > 2.5 have β = -1.48 ± 0.04 (Figure 11). This demonstrates that there is a faster evolution in measured sizes for spheroid-like galaxies, which therefore have a more effective increase in size over cosmic time than the disk-like objects.

Figure 11
Figure 11. The average sizes of massive galaxies selected with M* > 1011 M⊙ as imaged in the POWIR (Conselice et al. 2007) z < 2 data and GNS > 1.5 images (Buitrago et al. 2008; Conselice et al. 2011). The size evolution is divided into galaxies with elliptical-like profiles, with Sérsic indices n > 2.5, and disk-like profiles having n < 2.5. The measured effective radius, r e, is plotted as a function of the ratio with the average size of galaxies at the same stellar mass measurements with M* > 1011 M⊙ at z = 0 from Shen et al. (2003).

This size evolution is such that the effective radii of massive galaxies increases by up to a factor of five between z = 3 and today at the same stellar mass (e.g., Buitrago et al. 2008; Cassata et al. 2013). The form of this evolution has been investigated to determine whether or not the increase is due to the build up of the entire galaxy or just the inner or outer parts. The data to date show that galaxy growth through sizes is occurring in its outer parts, with the central parts in place at early times (e.g., Carrasco et al. 2010; van Dokkum et al. 2010). This indicates that the build up of massive galaxies is an inside out process, whereby the inner parts of massive galaxies are in place before the outer parts with the same stellar mass density as today (e.g., Hopkins et al. 2009).

An alternative way to investigate this problem is to examine the number of compact and ultra-compact galaxies at various redshifts. There is some controversy over whether or not there exist in the local universe compact galaxies with sizes similar to those seen at high redshifts. However, what is clear is that the number densities of these ultra-compact galaxies declines in relative abundance very steeply at z < 2 (Cassata et al. 2013).

The processes responsible for this increase in sizes at lower redshifts is not well understood, and is currently a source of much debate. The most popular explanation is that this size increase is produced through minor mergers (e.g., Bluck et al. 2012; McLure et al. 2013), although other ideas such as AGN performing work on gas is another idea (e.g., Bluck et al. 2011). However, the outer parts of nearby massive galaxies are too old to have been formed in relatively recent star formation, and the star formation observed at high redshift is not sufficient to produce the observed increase in sizes (Ownsworth et al. 2012).

The major idea for the physical mechanism producing galaxy size evolution is through dry minor mergers, as major mergers are not able to produce the observation of increasing size without significantly increasing mass (e.g., Khochfar & Silk 2006; Naab et al. 2009; Bluck et al. 2012; Oser et al. 2012; Shankar et al. 2013). There is currently some controversy over whether or not the observed minor merger rate is high enough to provide this increase in sizes, with the most massive galaxies with M* > 1011 M⊙ appearing to have enough minor mergers (e.g., Kaviraj et al. 2009) to produce this size evolution (Bluck et al. 2012), but this may not be the case for lower mass systems (e.g., Newman et al. 2012). It does appear however that minor mergers are a significant mechanism for producing low levels of star formation in early-types at z ~ 0.8, as well as for adding significant amount of stellar mass to these galaxies (Kaviraj et al. 2009, 2011). One of the major issues is determining not only the number of minor dry mergers, but also the time-scale for these mergers (Section 3.4) which more simulations would help understand.

Along with the evolution of galaxy sizes, there is also a significant evolution in the underlying structures of galaxies at higher redshifts. One of the cleanest ways to see this is through the evolution of the Sérsic parameter, n (Figure 7). When examining the evolution of derived values of n as a function of redshift for both a stellar mass and at a constant number density selection, it is apparent that galaxies have lower n values at higher redshifts for the same selection (e.g., Buitrago et al. 2013). This has been interpreted by some to imply that these galaxies are more ‘disk-like’ at high redshifts (Bruce et al. 2012), although the morphologies of these systems by visual inspection, and their internal structures and colors, are not similar to modern disks (e.g., Conselice et al. 2011; Mortlock et al. 2013). It appears that these disk-like galaxies, while having light profiles similar to modern disks, are much smaller, have a higher stellar mass, and are often undergoing intense star formation with peculiar morphologies, making them un-disk-like in all other regards. They indeed are likely a type of galaxy with no local counterpart.

Generally that entire webpage explains that in every measurable way, galaxies become increasingly different from how they look in present times, proportional to an increase in redshift. They become smaller in size, have different distributions of shape and structure, etc.

It would be very odd if the JWST suddenly reversed all these trends. It’s ridiculous on it’s face. Will it see weird, unusual, and unexpected things? I’m sure it will. Will they reverse current trends? I’m sure they won’t.


I think that requires removing the lower bound on the age, and really finding these galaxies (if that’s what they are) doesn’t seem very helpful in that respect. They aren’t even very helpful for a “quick maturation” model.

That would require separating the origin of the stars - and presumably planets - in the rest of the universe from that of the Earth. Typically the Sun would be thought to originate earlier, too. The latter in particular seems problematic.

I think you’re right that the distance doesn’t directly affect the red shift. But if you’re proposing light travelling faster then we have to ask why we don’t see evidence of that in closer objects. Or in other astronomical data (there was a proposal that light travelled faster in the early universe but I believe that didn’t work out, and still wouldn’t be anywhere close to enough for YEC timescales)

The evidence so far would seem more troubling to your hypothesis than to mainstream science then. We are seeing differences in galaxy size, for instance and nothing inconsistent with current science. And, as I’ve said it doesn’t seem at all helpful to YEC. OEC maybe, but even that would require something more dramatic than finding a few bigger galaxies at high red shifts.

Actually, I do not see anything in special revelation to indicate there should be distant galaxies at all. Who needs them? Not Adam nor Moses nor the revelator. In what way is a creationist hypothesis exegetical? It is neither science nor Biblical theology.

There is also no distant starlight problem. The light reaching the JWST took billions of years to traverse the distance. Scientifically speaking, that does not represent any sort of problem requiring any sort of solution.


But notice how that’s not actually a prediction of the hypothesis that the universe was created by God.

That’s rather more like a sort of ad-hoc rationalization because the universe we do see doesn’t seem to look like it’s 6000 years old, which you might take to imply it shouldn’t have a radius of more than 6000 light years. Anything beyond that shouldn’t be visible to us.
So since things much further away are still visible you’re forced to come up with these super weird “predictions” you have no reason for positing other than to try to square how the universe can still be 6000 years old.

Why should light travel faster towards Earth? No reason, other than the desire to force YEC together with hitherto made observations of the universe’s size and age. Why should the universe’s true age or size be unknowable if God made it? Again, no reason other than the motivation that current science not be allowed to contradict your religious views.

Is it not obvious to you that your position is based more on rationalizations than on the most sensible understanding of the available data?


Indeedy. Scientific predictions need mechanisms.

Here’s what I’ve used with 8-year-olds:

Hypothesis: My dog sits when I command her to because she understands the English word “sit.”

Experiment: Say “sit” in the usual way, say “sit” in an unusual way, and say a different word with the same intonation I use for “sit.”

Empirical predictions: Can you see what those are for the hypothesis being true or false, @thoughtful?

Can you see that the hypothesis is scientific because it is falsifiable, that whether it is actually true or false has nothing to do with that classification?

Rebecca Smethurst discusses claimed new distance records in the JWST data, 6:45 - 10:31 in this YouTube

Nope, Webb HASN’T found the most distant galaxy (yet!)


Of course there is.

Yeah there is no reason for thinking the speed of light has some different speed in the opposite direction. It’s a ridiculous rationalization.

Does anything else in nature behave that way? Do electrons in a wire travel slower or faster going in the opposite direction? Waves in water? Alpha particles emitted by unstable nuclei? Nothing else behaves that way, and nothing about the behavior of light seem to imply in the slightest that it’s somehow different in this respect.

And why of all things would light travel faster towards Earth, again? How does the light know it’s going towards Earth when leaving some distant galaxy and why would that make it go faster?

Again it’s just some nonsensical rationalization only invented to avoid the conclusion that cosmic distances is a problem for YEC. It is not necessary to explain anything we actually see in astronomy or physics, it improves our understanding of, or explanatory power for nothing at all. It’s just some additional complication of literally no scientific or rational use or consequence. An actual example of a “rescuing device.”

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Additionally, there are some things we see that would take a long time to develop: expanding nebulae from supernova remnants, colliding galaxies, and such. Even if we’re seeing them as they are right now, their existence implies a long prior history, in the millions or billions of years. Of course, God could have created them in their observed states, but that’s one of those deceptive deity things.

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I’ve always said my position is based on the Bible, so I chuckled that you asked the question. Whether that is sensible or not is a matter of opinion.

Ok, no measurable one-way speed of light.

The rationalization is not that light would have a different speed in the opposite direction, IMO. Instead because the one-way speed of light cannot be measured, it means it could be compatible with exotic physics that affect a one-way speed under certain conditions.

Why would the one-way speed be any different than the two-way speed?

Why would the one-way travel of light affected by different physics than the two-way travel? Why would bouncing a photon off a mirror change the laws of physics?


But you are able to “run the thought experiment” where you just base your position on the Bible not being true and you see the problem with that, right?

Shouldn’t that teach you that assuming a conclusion out of the gate, in general, is a problem? And if you just assume X is true and you simply work to invent interpretations to make things you observe fit the assumption, then why are you even here to discuss, argue, debate, or whatever. I mean who cares about our opinions anyway if they’re just that when all is said and done? Why even bother with any of this when you’ve already decided where it must all lead?

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That does not seem to be very well thought-out. Do you have any idea how this exotic physics would work? At least what effects it would have if not the details. Would the light continue to move quickly in areas where the exotic physics no longer applied? If it would, why? What would the observable consequences be, and why?


It’s a problem that completely precludes any scientific approach.

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