James Webb Space Telescope Finds Most Distant Known Galaxy

Very large stars live very short lives.

Our star will live 10 billion years, the smallest stars will last trillions of years, the largest stars live less than 10 million years and some very early stars broke the models for how big they were and maybe lived much less long.

What happens is their cores go through stages of fusing an element until they run out, gravity takes over and shrinks the core until the next element ignites, fuses, and runs out, down to iron. At one of those stages the collapse triggers a supernova (or one of the class of ways a star can die) instead.

It's interesting that [1] has a diagram showing that in 2022 the NASA diagram claimed that stars & galaxies formed 400M years ago so this feels like a big shift to having a massive galaxy already at 300M with data suggesting it's formed after several generations of stars.

> All of these observations, together, tell us that JADES-GS-z14-0 is not like the types of galaxies that have been predicted by theoretical models and computer simulations to exist in the very early universe

This is exciting. Maybe our understanding of the Big Bang is extremely flawed & this data is just the first inklings that we have to reimagine what we know about it?

Multiple generations is perhaps an overstatement. The first oxygen in the Universe came from what we call Population III stars which is the first generation of stars to form after the Big Bang and what separates these from other stellar populations is that they do not have elements heavier than hydrogen or helium (except for minuscule traces left over from the Big Bang but these are insignificant). Now we don't know much about Population III stars but many models predict they are massive and when they die, can release 60 times the mass of our sun in the form of oxygen. That's really a lot of oxygen so you don't need too many of these to go off to pollute the early Universe and probably one of the reasons why we haven't yet found Population III stars.

The scale of both time and space are the least confusing things in our universe, to me at least.

This is ridiculous. Assumes that Oxygen only is created by stars. Oxygen is one of the most abundant elements created during LENR (Low Energy Nuclear Reaction, formerly known as Cold Fusion) experiments.

https://www.nature.com/articles/s41598-023-50824-8

Just to rub it in, it's worse than that: it's always flying away from us, and it looks currently like that rate is accelerating. We don't even get to see this galaxy evolve, as we watch it will eventually appear to freeze in time from our perspective as it dims and red-shifts into the background radiation.

this is a slice of a tiny, tiny, tiny piece of space in a particular spectrum.

Also, relative motion is a thing. It's easier to bin a lot of images from distant, stationary objects than to do so for "nearby" moving objects.

If you google "why can't we image the Moon with hubble"

You'll find a lot of better answers like https://www.reddit.com/r/askscience/comments/jd83ue/why_is_i...

Other funky reasons: long exposure images through small slices of the sky can have less noise than "larger" chunks nearby, that are moving. Nearby objects need to deal with things like the zodiacal light, gegenshein, astroids, the glare of the Sun and reflections off of planets and a number of other things, as well as the glare of stars, which there are many more of in larger fields of view than 6 arc minutes.

A bad analogy:

this is imaging a gnat through a empty space in a square of a screen door. What you want to see is a bear through Gauze.

I wouldn't say it's too damaging yet. There is a general trend where these early galaxies are brighter than we had thought by simply extrapolating models that were built prior to JWST, but these make numerous assumptions on how efficiently stars can form and the properties of these stars. Mildly relaxing any of these assumptions can easily solve the problem within our current framework and not significantly change what happens later in the evolution of the Universe.

Your unit is wrong. Giga means billion. The universe is ~14 Gyr old.

Only maybe in the dense core of a galaxy because incident radiation falls off with the square of distance.

The nearest star to us after the Sun is ~4ly away, or ~250k AU. The Sun would have to be ~63 billion times brighter to give the same incident radiation at 250k AU, and that is just a typical distance between stars in our neighborhood . The Sun is also brighter than the average star, especially the older stars that congregate near the galactic center.

Galaxies can easily have 1 trillion stars but they are usually so spread out as to make this impractical. This is also why the Milky Way, Triangulum, LMC, SMC, and Andromeda (nearest galaxies) are so faint to the naked eye.

… imagine what’s behind our galaxy!

It's a lot less sophisticated than that. They take images in multiple filters. In the context of JWST of order 10 filters (sometimes more sometimes less). Source extraction is then performed on the images by essentially identifying bright spots and dropping an aperture (separating ones that are nearby and blended if possible). The standard tool for this is called source extractor. They then have catalogs of tens of thousands of sources per image and the next step is to figure out redshift. There is a lot of code to do this but the simplest methods require fitting templates of what we think galaxies look like to these catalogs. High redshift sources tend to "drop" out of filters at shorter wavelengths. This is because neutral hydrogen in the early universe essentially absorbs almost all of the light at shorter wavelengths than 1216 angstroms. So if a galaxy is at redshift 10, the flux should essentially be zero at all filters that cover wavelengths shorter than 1.33 microns. JWST has filters both bluer and redder than this wavelength so we see the source appear in the redder filters and not the bluer ones. This technique was pioneered in the mid 1990s. This gives an approximate redshift called a "photometric redshift". There are other features in a galaxy spectrum that can mimic this "dropout" so not all photometric redshifts are robust. Therefore one has to take a spectrum of the galaxy which was what was done in this paper to confirm that the dropout is in fact the absorption feature we think it is. In this particular case, the authors were skeptical early on because there is a source right next to the object that is at a redshift where one of these other spectral features can mimic absorption by neutral hydrogen (this feature is the Balmer break). In any case, it's really an impressive demonstration of the power of JWST.

I'm not sure I understand your distinction, can you explain why you wish that?

My understanding is that there is a linear correlation between the redshift of a galaxy and the distance to the milky way (for distant galaxies where the peculiar velocity is negligible). So, the most redshifted galaxy is the most distant galaxy.

But, I'm just a layman who enjoys astronomy, so I'd appreciate an explanation on why the distinction is important.

Curious minds do want to know what type of outfits to pack when visiting.

The JWT cost more both in dollars and time than the Manhattan Project.