James Webb Space Telescope Finds Most Distant Known Galaxy(blogs.nasa.gov)
blogs.nasa.gov
James Webb Space Telescope Finds Most Distant Known Galaxy
https://blogs.nasa.gov/webb/2024/05/30/nasas-james-webb-space-telescope-finds-most-distant-known-galaxy/
58 comments
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 word "generation" isn't really a thing in astronomy jargon. "Population III" is a population, and it includes stars formed after some supernovae, up to the point where the metals % gets high enough to be Population II.
Big stars burn hot and fast, the more mass, the shorter their lives
Pop III stars (if they existed) are really a mystery, we can't easily extrapolate. These stars would be purely hydrogen and helium so it would take them a surprisingly long time to get to CNO cycle, for example.
Why would it take a Pop III star longer than an equivalent-mass Pop I or II star to reach the end of its H / He fusion cycle?
Because of the lack of C, N, and O, which are catalysts in the CNO cycle. They aren't produced by it.
NB: based on some quick searches, it seems that low-metalicity Pop III stars would rely on the pp (proton-proton) fusion chain. That's going to slow reaction somewhat, and extend lifetime. But for high-mass stars with only a few millions of years expected lifetime in a Pop I/II class, that's ... still a relatively modest difference compared to the several hundred million year lifespan of the early Universe.
Or am I missing something?
Or am I missing something?
Another interesting quirk of Pop III stars is that their initial mass function is expected to form much more massive stars than Pop II or Pop I. So even if Pop III stars are longer lived at the same mass as Pop II or Pop I, there will be a lot more supernovae per time, leading to fast enrichment and then Pop II.
That was one of my thoughts.
Another is that p-p fusion is fairly common. Look up when the Big Room's bright and you'll see a ... stellar example yourself ;-)
(p-p fusion dominates in stars < ~1.3 M, where M is a solar mass. CNO fusion is typical of more massive stars.)
Another is that p-p fusion is fairly common. Look up when the Big Room's bright and you'll see a ... stellar example yourself ;-)
(p-p fusion dominates in stars < ~1.3 M, where M is a solar mass. CNO fusion is typical of more massive stars.)
Thanks!
So I think it is fair to say they did exist. If we believe in Big Bang Nucleosynthesis then heavy elements had to come from somewhere making the first generation of stars (whatever their properties may be) be Population III. I agree that without a catalyst it's hard to initiate the CNO cycle but indeed models predict that it is possible even under these circumstances.
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?
> 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?
> formed 400M years ago
do you mean formed 400M years after the big bang instead of 400M years ago from today? That's like yesterday to the Universe.
do you mean formed 400M years after the big bang instead of 400M years ago from today? That's like yesterday to the Universe.
Correct. Obviously not 400 mya.
No. The diagram https://science.nasa.gov/resource/history-of-the-universe/ tells us that galaxies and dark matter formed 400M years after the big bang. Look at the right of the chart legend: "13.8 billion years" is above "today".
And this observed galaxy formed less than 300M years after the big bang. The chart is now wrong.
That's the beauty of theories in that they can be proven right or wrong. Thanks to the JWST, a lot of theories are needing to be updated. We're just now being able to actually test those theories. At some point, these types of charts will be updated.
As you stated, it is exciting times.
As you stated, it is exciting times.
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.
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.
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
https://www.nature.com/articles/s41598-023-50824-8
It is interesting to think about what could be from a galaxy that was formed ~500 million years before ours.
If life had formed in that galaxy, if somehow it had followed a similar pattern we did (which is doubtful, but just a thought experiment for simplicity). It would be very interesting to see a glimps of where life could be with an "extra" 500 million years. Even just a few million considering homosapiens did not appear until ~300,000 years ago.
It is almost sad in a way that we now know this galaxy exists, but we will always be looking at it 13+ billion years away and will never know what it is now. Can never really compare what that 500 million year head start got it (assuming it still exists).
If life had formed in that galaxy, if somehow it had followed a similar pattern we did (which is doubtful, but just a thought experiment for simplicity). It would be very interesting to see a glimps of where life could be with an "extra" 500 million years. Even just a few million considering homosapiens did not appear until ~300,000 years ago.
It is almost sad in a way that we now know this galaxy exists, but we will always be looking at it 13+ billion years away and will never know what it is now. Can never really compare what that 500 million year head start got it (assuming it still exists).
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.
1. Why doesn't the press release state the actual distance? ChatGPT says about 30 billion light years.
2. How can we observe objects 30 billion light years away, but can't rule out another planet past pluto?
2. How can we observe objects 30 billion light years away, but can't rule out another planet past pluto?
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.
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.
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For any astronomers here, or others with the relevant knowledge of astrophysics, a question: this discovery would suggest the existence of a fully-formed galaxy at ~290 gigayears (Gyr), when the first stars are presumed to have emerged between 200 and 300 Gyr. How badly does this damage current models of early galaxy formation, and what new physics might it suggest?
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.
I wonder if a galaxy like this could be so bright as to support life on rogue planets i.e. those not orbiting a star?
(If there would be any elements to create a rocky planet from. However the article states they were surprised to detect signs of dust and oxygen already in such an early galaxy.)
(If there would be any elements to create a rocky planet from. However the article states they were surprised to detect signs of dust and oxygen already in such an early galaxy.)
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.
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.
Carrying on from that first sentence:
"in the center of the galaxy, stars are only 0.4–0.04 light-years apart"
The most luminous stars going by Wikipedia are about 5 million times brighter than the Sun. Not sure if those are anywhere near galactic centres though.
"in the center of the galaxy, stars are only 0.4–0.04 light-years apart"
The most luminous stars going by Wikipedia are about 5 million times brighter than the Sun. Not sure if those are anywhere near galactic centres though.
I could be armchair astronomying wrong here - but something that blows my mind: this image represents 6.2 arcminutes across in the field of view, that's 10x smaller than the size of Andromeda in the night sky. Imagine what's behind Andromeda!?
… imagine what’s behind our galaxy!
everything and nothing :)
We can see some things behind it, with neutrinos and gravity waves.
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I think the most interesting question is how such early galaxies can even exist. How does this fit to our current throretical models.
Anyone know the algorithmic approach to finding this? I assume they ran an ML over the dataset with a search function to figure it out.
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.
If I understand this correctly its like a mask between filters and the differential makes that differential much more noticeable? Wouldn't one of the challenges be that the pictures have to be almost the exact same time with those filters so that they line up perfectly to provide the differential given the high resolution?
Also thanks for the detailed response - their approach sounds like a smart solution minimizing unnecessary compute cost / algorithm scanning.
Also thanks for the detailed response - their approach sounds like a smart solution minimizing unnecessary compute cost / algorithm scanning.
These galaxies are so far away that they're very small on the sky, even at JWST's resolution. There's a reason why they're called "little red dots"!
> less sophisticated
lol.
Thanks for this breakdown, it was super interesting to read about what signal processing techniques are used for this kind of thing!
How does the actual "searching" take place, do they just run this kind of procedure at every bright spot in the image and rank candidate sections?
lol.
Thanks for this breakdown, it was super interesting to read about what signal processing techniques are used for this kind of thing!
How does the actual "searching" take place, do they just run this kind of procedure at every bright spot in the image and rank candidate sections?
This is breathtaking. I marvel at what we are able to see. Small quibble though: I wish they would say, '... finds galaxy with the highest known redshift.' Maybe not so pompous, but especially after all the recent news about the size and age of the universe due to JWST observations.
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.
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.
It's linear for small redshifts only. In general it depends on what distance you mean, but it's never linear. This does not change the validity of your argument of course.
Check https://en.m.wikipedia.org/wiki/Distance_measure
Check https://en.m.wikipedia.org/wiki/Distance_measure
You are right, of course. But that is based on our standard cosmological model.
But there is some controversy in this respect. It is not as clear cut as the relationship with C14 and age, for instance. There are some recent discoveries of galaxies that if their age and distance are correct clearly contradicts the standard cosmological model. But, even if I am right, it is a small nitpick. I think from this news I rather just wonder.
But there is some controversy in this respect. It is not as clear cut as the relationship with C14 and age, for instance. There are some recent discoveries of galaxies that if their age and distance are correct clearly contradicts the standard cosmological model. But, even if I am right, it is a small nitpick. I think from this news I rather just wonder.
"The data reveal other important aspects of this astonishing galaxy. We see that the color of the galaxy is not as blue as it could be, indicating that some of the light is reddened by dust, even at these very early times."
We continue to see evidence that the universe is older than first believed.
We continue to see evidence that the universe is older than first believed.
- "Editor’s Note: This post highlights data from Webb science in progress, which has not yet been through the peer-review process."
Here's the preprint they won't link:
https://arxiv.org/abs/2405.18485 ("A shining cosmic dawn: spectroscopic confirmation of two luminous galaxies at z∼14")
Here's the preprint they won't link:
https://arxiv.org/abs/2405.18485 ("A shining cosmic dawn: spectroscopic confirmation of two luminous galaxies at z∼14")
Enough of this
We need a Manhattan level project to find life.
That's it.
We need a Manhattan level project to find life.
That's it.
The JWT cost more both in dollars and time than the Manhattan Project.
Not if you're looking at inflation-adjusted dollars, though the values are closer than I'd have thought.
1945 cost of the Manhattan Project, $1.89 billion,[1] or $32.9 billion 2024 per <https://www.usinflationcalculator.com/>.
2016 cost of the JWST: ~$10 billion,[2] or $13.1 billion 2024 adjusted for inflation.
That's a smaller multiple for the Manhattan Project than I'd have expected, but it's still comfortably more expensive than the JWST.
________________________________
Notes:
1. <https://en.wikipedia.org/wiki/Manhattan_Project#Cost>
2. <https://en.wikipedia.org/wiki/James_Webb_Space_Telescope>
1945 cost of the Manhattan Project, $1.89 billion,[1] or $32.9 billion 2024 per <https://www.usinflationcalculator.com/>.
2016 cost of the JWST: ~$10 billion,[2] or $13.1 billion 2024 adjusted for inflation.
That's a smaller multiple for the Manhattan Project than I'd have expected, but it's still comfortably more expensive than the JWST.
________________________________
Notes:
1. <https://en.wikipedia.org/wiki/Manhattan_Project#Cost>
2. <https://en.wikipedia.org/wiki/James_Webb_Space_Telescope>
arguably we wouldn't have JWST without Hubble, so cost adjusted they're about the same, then again, there is probably some "prior art expensive project" associated with Manhattan, but I didn't check :)
That's ... a somewhat freighted avenue, and it's difficult to determine where to draw lines.
Hubble itself strongly leveraged Key Hole, as a further extension:
<https://en.wikipedia.org/wiki/KH-11_KENNEN>
As for the Manhattan Project, it was sufficiently close to the first direct theoretical and applied theory and proofs of sustainable nuclear chain reactions (roughly a decade or less following each), and a lack of understanding of the corresponding risks (which greatly increase costs) that there simply wasn't time to have spent all that much money.
By contrast, Hubble and JWST are both late-stage, highly-evolved technologies, pushing the engineering envelope in many dimensions simultaneously, all of which tends to increase costs.
See for example the ELT (extremely large telescope), an Earth-based instrument currently under construction in Chile as part of ESO (European Southern Observatory). Tom Scott's 'splainer video on the project explains how costs risk exponentially with increased size for numerous reasons.
<https://en.wikipedia.org/wiki/Extremely_Large_Telescope>
<https://yewtu.be/watch?v=QqRREz0iBes>
Hubble itself strongly leveraged Key Hole, as a further extension:
<https://en.wikipedia.org/wiki/KH-11_KENNEN>
As for the Manhattan Project, it was sufficiently close to the first direct theoretical and applied theory and proofs of sustainable nuclear chain reactions (roughly a decade or less following each), and a lack of understanding of the corresponding risks (which greatly increase costs) that there simply wasn't time to have spent all that much money.
By contrast, Hubble and JWST are both late-stage, highly-evolved technologies, pushing the engineering envelope in many dimensions simultaneously, all of which tends to increase costs.
See for example the ELT (extremely large telescope), an Earth-based instrument currently under construction in Chile as part of ESO (European Southern Observatory). Tom Scott's 'splainer video on the project explains how costs risk exponentially with increased size for numerous reasons.
<https://en.wikipedia.org/wiki/Extremely_Large_Telescope>
<https://yewtu.be/watch?v=QqRREz0iBes>
For some reason this quote blew me away. It's just so hard to comprehend the timescales and vastness of the universe.