It's Milky Ways all the way back! (Interesting New Paper #1)
A paper digging deep into new data from the James Webb Space Telescope has just flipped everything we thought we knew about early galaxies on its head
An extraordinary new paper was published a few days ago, on September 22nd, in the Astrophysical Journal. It confirms something which had already become increasingly clear over the last year (as the James Webb Space Telescope released more and more data): large spiral galaxies occur far earlier, and in far larger numbers, than mainstream astronomy or cosmology had expected or predicted. In fact, the paper conclusively shows not only that big, stable, structured, spiral galaxies like our own Milky Way exist in large numbers right back as far as we can currently see, but that such spiral galaxies contain, and have generated, most of the stars in the universe.
This is HUGELY encouraging for the Evolved Universe hypothesis that I am exploring here – it means that my predictions of extremely rapid galaxy formation in the early universe have turned out to be correct. Several papers from earlier this year gave strong hints that this was the case, but they were looking at very small numbers of galaxies, so it was possible they had accidentally stumbled upon a handful of outliers, and it wouldn’t apply more generally.
However, this is a BIG survey, which makes the evidence far stronger; they’ve looked at almost four thousand extremely distant (and therefore early) galaxies – which is about twenty times more than any earlier, similar, survey.
They divided the galaxies into three categories
Disk (Basically spiral galaxies, like our Milky Way.)
Spheroid (Ball-shaped galaxies.)
Peculiar (All the weird ones left over.)
And then they measured each galaxy’s redshift – how stretched out its light has become, on the long journey to us through an ever-expanding universe. (The more distant the source of the light, the more that light will have been stretched, and thus shifted towards the red end of the spectrum, by the time it arrives.)
That told them how old each galaxy was; how long after the Big Bang we were capturing its light.
Then they analysed the results, to see how many galaxies of each type (disk, spheroid, or peculiar) existed at each era; that is, to see how the shapes of galaxies come about, and how they change over time.
The old assumption was that highly structured spiral galaxies came about slowly and late, through bottom-up structure formation. Bottom-up structure formation essentially means order arising very, very slowly from a lot of randomness, as early solitary stars clump (under the influence of gravity) to form star clusters, which clump to form dwarf galaxies, which merge to form small, irregularly-shaped galaxies, which merge to form larger also peculiarly-shaped galaxies, some of which eventually settle down and find a spiral structure. But the assumption was that you simply couldn’t get large numbers of spiral galaxies in the first few billion years of the universe’s existence, as, even if they had somehow managed to form, they would be disrupted by all that clumping and merging.
This model had come under strain in the Hubble Space Telescope years, as we looked back further and further into the past, closer and closer to the Big Bang, and still saw large spiral galaxies, and thus began to run out of time for all this slow, random, accretion. But a LOT of early galaxies still looked pretty irregular or peculiar to the Hubble (though the resolution of those images was poor, so it was hard to tell); and so the model just about survived.
Not any more.
Here’s the key finding, from the paper (with a breakdown of what it all means underneath):
“…galaxies with M* > 10^ 9 M⊙ at z > 3 are not dominated by irregular and peculiar structures, either visually or quantitatively, as previously thought. We find a strong dominance of morphologically selected disk galaxies up to z = 6 in this mass range. We also find that the stellar mass and star formation rate densities are dominated by disk galaxies up to z ∼ 6, demonstrating that most stars in the Universe were likely formed in a disk galaxy.”
–from the paper, The JWST Hubble Sequence: The Rest-frame Optical Evolution of Galaxy Structure at 1.5 < z < 6.5, by Leonardo Ferreira, Christopher J. Conselice, Elizaveta Sazonova, et al, published in the Astrophysical Journal, September 22nd 2023. (Official citation, in case that’s useful for you: Leonardo Ferreira et al 2023 ApJ 955 94)
That’s devastating for the old model. And FANTASTIC news for the model of rapid, early, galaxy formation, driven by direct-collapse supermassive black holes, that I’ve outlined on this Substack.
Let me break it down:
“…galaxies with M* > 10^ 9 M⊙ at z > 3 are not dominated by irregular and peculiar structures, either visually or quantitatively, as previously thought.”
M⊙ stands for the mass of our sun, which we use as a handy measuring unit for the mass of galaxies. M* is the stellar mass of an entire galaxy: the mass of all the stars (so, not the gas, not the dark matter; just the stars). And z is the redshift: the greater the redshift, the greater the distance away from us in space and time – and thus the closer to the Big Bang, and the birth of the universe.
A z of 3 – a redshift of three – is, roughly, a couple of billion years after the Big Bang. So that line means that the large galaxies that they observed a couple of billion years after the Big Bang (that’s galaxies larger than 10-to-the-9 solar masses, so a billion times more massive than our sun), are not mostly irregular or peculiar in shape, as had been assumed.
Essentially, the powerful new measuring instruments of the James Webb Space Telescope, launched last year, are able to get a much clearer picture of these galaxies, which looked irregular or peculiar to the Hubble Space Telescope; in fact, they turn out to be, in a huge number of cases, spiral galaxies with well defined structures. Many of them have clearly visible spiral arms; some have bars.
How come the Hubble got this so wrong? Several reasons: one is simply that the Hubble didn’t have the resolution to pick up on these details. Remember, the day it launched, on April 24th 1990, Sinéad O'Connor was at number one with "Nothing Compares 2 U”; the Hubble Space Telescope is now 33 years old. Yes, NASA have updated a lot of the original equipment since (the Hubble is the only space telescope designed to be serviced by astronauts); but the huge Wide Field Camera 3 (WFC3) they used to image these galaxies was installed in 2009, by astronauts using the Space Shuttle. (Back when Boom Boom Pow by The Black Eyed Peas was at number one.) Imagine how much digital camera technology has improved since 2009: the Hubble images are REALLY small and smudgy and hard to interpret.
Have a look for yourself: Here are thirteen galaxies, stacked. In each row, on the left, you can see four images (taken at four different wavelengths) by the Hubble Space Telescope. On the right, you can see six images of the same galaxy taken by the James Webb Space Telescope.
A second reason Hubble didn’t see spirals is that the Hubble is largely a visible-light telescope, and so the wavelengths which the Hubble was designed to detect were the wrong ones for picking out such structure at that distance. Remember, light coming from that distance has been heavily redshifted; a lot of the visible light has moved well into the infrared. Hubble’s WFC3 can see a little bit into the infrared, but not far: it is deliberately designed to lack sensitivity beyond 1700 nanometers, because the heat of the Hubble itself would completely drown out the images otherwise. (Heat is infrared light, and so the Hubble, unfortunately, glows with warmth in exactly the range these galaxies also now glow in, drowning out their dim light. The James Webb Space Telescope, by contrast, is cooled to near absolute zero, and so can see far further into the infrared range.)
And so Hubble, it turned out, was often only able to see the (brighter, bluer, more energetic) light from the hot, star-forming regions of these extremely distant galaxies: those regions were irregular or peculiar in shape, but the galaxy as a whole was, in fact, a spiral. And the James Webb Space Telescope’s instruments are able to detect the galaxy as a whole – not just the hot star-forming regions – because it’s an infrared telescope, it’s specifically designed for this kind of task, and so its instruments are picking up those longer, cool, redder wavelengths of light which the Hubble missed, and which are given off by the older, cooler stars in the rest of the galaxy.
But a third reason is that the astronomers and cosmologists analysing the original Hubble data had a strong bias towards finding randomness, blobbiness, lack of structure; it was what their theory predicted. And so they looked at photos of spiral galaxies taken by Hubble, and interpreted them, not as showing the star-making regions of spiral galaxies, but as showing peculiar, odd-shaped, random blobby galaxies. This is yet another example of the phenomenon I described in my earlier post, In cosmology, all our errors lean the same way…
“Our universe always turns out to be bigger, more structured, more complex, and more weirdly efficient, than we've anticipated…
(…)
…above all, until they start using egg physics rather than rock physics, they {astronomers} will be blindsided particularly badly in the early universe; particularly in the first billion years – the last refuge of randomness – where they thought they would, finally, find random matter blindly obeying arbitrary laws – and where instead, again and again (as I predicted), they are finding the structure, and order, of an evolved organism efficiently and rapidly proceeding along a clear developmental path.”
-Me, being annoyingly right, again, back in May.
OK, back to the paper. What’s next?
“We find a strong dominance of morphologically selected disk galaxies up to z = 6 in this mass range.”
That means that disk galaxies – galaxies like our own Milky Way – dominate from redshift 3 to redshift 6. Which means from a couple of billion years after the Big Bang back to a billion years after the Big Bang. (Why stop at a billion? Because it’s still REALLY hard to see any detail in anything much further back than that, even for the James Webb.) MOST big galaxies that the Hubble had classified as irregular or peculiar were misclassified. And have now been reclassified. And this has implications for all the galaxies of that era.
So, a huge number of galaxies that LAST WEEK were officially classified as irregular or peculiar in shape are now officially well-structured spiral galaxies. OUR ENTIRE PICTURE OF THE EARLY UNIVERSE just changed, overnight.
What’s next?
“We also find that the stellar mass and star formation rate densities are dominated by disk galaxies up to z ∼ 6, demonstrating that most stars in the Universe were likely formed in a disk galaxy.”
Well, that’s pretty self-explanatory. Most of the stars up to redshift 6 (a billion years after the Big Bang), are found in spiral galaxies, and most of the star formation up to redshift 6 is also happening in spiral galaxies: so, most stars in our universe were formed in (large, structured) spiral galaxies. That is, it’s not bottom-up structure formation, with a long early period of small, random, blobby little clumps slowly forming galaxies, at all. Structures start early, and drive star formation. Which is what I predicted before the James Webb Space Telescope released its first data.
Of course, it is still perfectly possible that the specific, detailed formation mechanism I suggested in that post last year may yet turn out to be wrong, in whole or in part. It’s an ambitious, speculative leap. (Though, feck it, I’m actually even more confident after this paper.) But, after this stunning revision of the Hubble data, I’m clearly right about the big picture prediction: spiral galaxy formation is early, rapid, and efficient, far more so than the mainstream had anticipated. Just listen to Christopher Conselice, the lead author on this new paper:
“Using the Hubble Space Telescope we thought that disk galaxies were almost non-existent until the Universe was about six billion years old; these new JWST results push the time these Milky Way-like galaxies form to almost the beginning of the Universe. (…) Based on our results astronomers must rethink our understanding of the formation of the first galaxies and how galaxy evolution occurred over the past 10 billion years.”
–Christopher Conselice, Professor of Extragalactic Astronomy at The University of Manchester
Wow wow wow wow wow wow.
And remember, I predicted this in the teeth of the Hubble data. An evolved universe simply couldn’t have the kind of slow, chaotic, bottom-up structure formation that the Hubble was hinting at. A long period of early randomness just wouldn’t make sense: evolution should have tightened up the process of early structure formation by now. The transition from a cloud of gas to star-forming galaxies should be brisk and efficient.
And now we know… it is.
I don’t want bonus points for me, or my ego (my ego is doing fine); I want those bonus points for the theory. (I’m just riding on its back, teasing out its implications.) An evolved universe theory has now made big, solid predictions about the early universe that have proved correct. Not only that, but the evolved universe theory made those predictions in the teeth of existing data from the Hubble that pointed the other way; data which has now been completely reinterpreted, in precisely the way that the theory predicted it would be. Big, big win for the Evolved Universe model…
POSTSCRIPT ABOUT INTERESTING PAPERS
OK, what I found myself doing in the past, when a fascinating new paper like this dropped, was attempting to write a full, epic post about it, giving all the background, summarising the whole paper, teasing out all the implications, etc. But the amount of work involved (I often had to do a lot of fresh research, or even try to master a new sub-speciality) meant that those posts never got posted, because they took WEEEEEEKS, and something new always came up to bump them down my priority list before I could finish them.
So – though I do have much, much, much more to say on this subject – this is a short, punchy post, simply drawing your attention to the paper and its main findings (so you can go explore it yourself, if you like). I plan to experiment with more such short posts, when important, interesting, or otherwise intriguing new papers come out, which I will title, and tag, as “Interesting New Paper”.
Hot damn, though! What a win! Please do share this, or the original paper, with anyone you think might be interested. SERIOUSLY, SHARE IT! DON’T JUST SIT ON YOUR ARSE AND CHECK YOUR INSTAGRAM! GET INVOLVED! GET YOUR FRIENDS INVOLVED! SEND IT TO YOUR FAVOURITE SCIENCE-NERD FRIEND NOW, SO YOU HAVE SOMEONE TO TALK TO ABOUT THIS!
Isn’t this EXCITING? Isn’t this more interesting than ANYTHING ELSE? It looks like we might be right; the universe isn’t random, arbitrary, mere dead matter decaying: instead, and without breaking any laws of physics, without any woo-woo, it is developing, unfolding, rapidly, efficiently, right from the start, like an evolved organism; it’s going somewhere, and we are part of it.
Just read about this and wondered if you had thoughts about how it fits (or not) with evolved universes;
https://www.theguardian.com/books/2023/oct/30/white-holes-inside-the-horizon-carlo-rovelli-review-black-hole-quantum-physics
Hi Julian! A question I’ve had about the Evolved Universe model but didn’t want to go back and comment on an old post: in this model, black holes in one universe are the big bangs of the offspring universes—more black holes, more offspring. Does this not imply that each of the offspring universes has less total mass, by a huge factor? At some point do you run into a mass limit as you divide up the available mass into more and more offspring? Or am I missing something?