The mystery of the Little Red Dots has been solved – and once more Eggiverse triumphs over Rockiverse!

Three emails showing you a glimpse behind the scenes of science, during this fascinating transition to a new paradigm

A thrilling new paper, after much writing and rewriting, has finally passed peer review and been published, solving the mystery of the “Little Red Dots”: very early, very compact, very bright galaxies that, to the great surprise of the vast majority of astronomers, cosmologists, and astrophysicists, popped up in startling numbers in the background of every photograph of the early universe taken by the James Webb Space Telescope.

Little Red Dots! Photo courtesy NASA, and ESA, and their marvellous James Webb Space Telescope

The paper, “The Rise of Faint, Red AGN at z > 4: A Sample of Little Red Dots in the JWST Extragalactic Legacy Fields”, by Dale D. Kocevski, Steven L. Finkelstein, Guillermo Barro, et al. (Fifty-seven authors!), does a detailed spectral analysis of the light from 341 of those little red dots, to finally work out exactly what they are. And yes, it confirms what three-stage cosmological natural selection predicted: that the very early universe is dominated by active supermassive black holes, around which compact galaxies are rapidly forming. “Active” means these supermassive black holes are pulling in a lot of gas, and pumping out a lot of energy, making these young galaxies far brighter than if you just measured the light from their stars. And yes, these supermassive black holes are far larger, and far more numerous, and appear far earlier, than had been predicted by any other theory. This paper is a resounding triumph for three-stage cosmological natural selection. (A theory which really needs a far snappier name; something cheeky and memorable, à la “black hole”, or “big bang”. In honour of the organising metaphor for my book, I’m thinking of going with Eggiverse for now, which makes the old paradigm the Rockiverse. Please do make your own suggestions in the comments…)

As a bonus, the paper reveals that some of these Little Red Dots also show signs of gas outflows near the black hole, which is evidence for the extremely early, powerful, sustained jets which I believe are the main force (along with gravity, obviously) behind structure formation in the early universe. (See, eventually, my forthcoming mega-post on Blowtorch Theory: Structure Formation in the Early Universe, when I finally finish editing and polishing the damn thing.)

To celebrate all this, I’m publishing three emails from May last year, that throw an interesting light on how and why the mainstream astronomical community had trouble initially interpreting the data they were getting from the James Webb. (Their preconceptions, understandably and very humanly, made it hard for them to see what they were looking at. Yes, All Cosmology’s Mistakes Continue To Lean In the Same Direction.)

Marc Kamionkowski, Julian B. Munoz, and Nashwan Sabti are three (extremely respectable, and mainstream, and excellent!) cosmologists who suspected, earlier than most, that there was something wrong with how the James Webb data was being interpreted. They laid out their argument in their thoughtful February 2024 paper, in Physical Review Letters, “Insights from HST into Ultramassive Galaxies and Early-Universe Cosmology”.

That paper pointed out that the way mainstream astronomy was interpreting the James Webb Space Telescope (JWST) data simply didn’t make sense, in the light of our existing Hubble Space Telescope (HST) data. Mainstream astronomers were interpreting all the brightness, all the light, from these tiny, distant, early, red galaxies (as captured by the James Webb Space Telescope), as being made by stars alone: but for that to be true, those extremely young galaxies would have to be packed with more stars than we saw in similar but much older galaxies (as captured by the Hubble Space Telescope). Many galaxies would have to become significantly smaller over time for the two sets of data to match up.

So there was clearly a serious problem with the way mainstream cosmology was interpreting these little red dots.

I thought I knew the answer, so I emailed Marc a question. He replied, and copied in his co-author, Julian B. Munoz, who also replied. Their answers were fascinating, and so Marc and Julian B. have both very kindly given me permission to publish our brief email correspondence here. (Or, as Marc less formally actually said, I’ve looked it over, and there’s nothing too incriminating…) So, three emails…

Little Red Dots are REALLY LITTLE! You can see here how far you have to blow them up to see them at all. But they are EVERYWHERE in the early universe, and thus lurking in the background of all the James Webb infrared photos of closer and more recent things. Picture courtesy NASA, ESA, and the glorious James Webb Space Telescope.

EMAIL ONE, JULIAN GOUGH TO MARC KAMIONKOWSKI

My May 2024 email to Marc Kamionkowski, an excellent theoretical physicist at John Hopkins University, who specializes in cosmology and particle physics. It was a cold email, i.e. I’d never made contact with him before, thus the rather boastful-sounding intro – very embarrassing and difficult stuff for an Irishman to write, but of course you’re asking for the valuable time of a busy person, so you have to show them you are serious about your work, and that this stranger and their project are worth engaging with. Oh well, I told you I’d show you the embarrassing behind the scenes work that goes into writing a book!

24 May 2024, 12:42pm

Dear Marc,

I'm intrigued by your recent paper, Insights from HST into Ultramassive Galaxies and Early-Universe Cosmology, and I'd love to ask you a question about it.

I know that cosmologists get a lot of crank emails from lunatics, so here's a quick bit of personal background/social validation, to (I hope!) reassure you that I'm not a nut, and this email is worth answering: I'm an Irish writer based in Berlin. I usually write novels and children's books (which are now published in 37 languages). I've also written some more unusual things, like BBC radio plays, the first short story ever published by the Financial Times, and the ending to the most successful computer game of all time, Minecraft.

Right now I'm writing a non-fiction book that explores, and expands on, Lee Smolin's old idea of cosmological natural selection. On the literary side, I've received funding for the project from the Irish Arts Council, and on the more scientifically rigorous side, I've received funding from Emergent Ventures, a grant-giving body for unusual but promising ideas run by the economist Tyler Cowen of George Mason University. People like Kevin Kelly (who founded Wired magazine), and Johannes Jaeger (former scientific director of the Konrad Lorenz Institute for Evolution & Cognition Research in Austria) think the project is interesting and are supporting it.

So, here's the question!

Assume that large numbers of direct collapse supermassive black holes form very early in the life of the universe (the first 100 million years or so), and seed the rapid early formation of galaxies around themselves. (Yes, this is a big assumption! But just assume it is the case for now.) Put another way, imagine that the early universe is full of galaxies like UHZ1; in other words, that Overmassive Black Hole Galaxies turn out to be ubiquitous. (As is now looking more likely, after the Yue/Eilers/Simcoe paper out of MIT this month, showing that six quasars at 5.9 < z < 7.1 have central supermassive black holes which average 10% the mass of their surrounding galaxies...)

In that case, could the tension between the Hubble data and the James Webb Space Telescope data be resolved if the early galaxies seen by the James Webb Space Telescope were not, in fact, far more massive than expected but were simply far BRIGHTER than expected, due to unexpected amounts of early quasar activity, as gas fell into the direct collapse supermassive black holes – and because this extremely bright quasar-light from the accretion discs is being interpreted purely as starlight, very large stellar mass is (wrongly) being assumed? (Of course, the early galaxies could still be more massive than anticipated, but not MASSIVELY so. And the quasars could be partially obscured by dust and gas, making it harder to tell they are essentially point sources.)

Is there anything currently in the data to rule this out as a possible explanation (however unlikely)?

Any answer, however brief or tentative, would be greatly appreciated! (If you prefer a brief phonecall or Zoom to email, that's fine by me too, whatever suits you best. My phone number is +49 *** *** ****.) It would be of huge help to me at this stage in the planning/writing of the book.

Best of luck with your excellent work.

Fond regards,

-Julian

EMAIL TWO: MARC KAMIONKOWSKI TO JULIAN GOUGH

24 May 2024, 22:44

Hi Julian,

You got me with Minecraft. My son is obsessed, and I might get some cred with him if I tell him I’m emailing with the author of the End Poem.

My first inclination is to say that the answer to your question is yes. I.e., I do think it may be possible that the Hubble and JWST data could be resolved if the JWST galaxies are simply a lot brighter, and not as massive as they are reported to be. Many of the inferences about these high-redshift galaxies are obtained by extrapolating relations for lower-redshift galaxies, and it is not clear whether those extrapolations hold up. I therefore take many of the implications reported from high-redshift JWST galaxies with a grain of salt.

About the second part: Could the light that they are interpreting as starlight be emission radiated from accretion onto the black hole? That’s an interesting question, but I’m not the best person to answer it. I know that the frequency spectrum from accretion disks looks a lot different than that from starlight (its distributed over a far broader range of frequencies and has a different spectrum of atomic lines), but I don’t know enough about the data to say whether they can distinguish this scenario from the standard one.

With this email message, though, I am introducing you to my collaborators Julian and Nash, both of whom have been paying far more attention to these JWST results than I. They are better equipped to give you good answers and also to point you to others if they are also not sure.

Cheers,

Marc

EMAIL THREE: JULIAN B. MUNOZ TO JULIAN GOUGH

25 May 2024, 01:03

Dear fellow Julian,

Nice to virtually meet you! You've hit the nail on the head. From photometry alone (that is, integrated light over some broad range of wavelengths) it's hard to distinguish an ultramassive galaxy from a fainter galaxy with a big AGN in the center (active galactic nucleus, which is to say a supermassive black hole). That's because the AGN will emit very broad and bright lines in that range, which when integrated can mask as a higher 'continuum' (light emitted by a lot of old stars). You need spectra to distinguish the two cases, which can show the broadening of the lines as Marc mentioned.

The interesting thing is that new results are finding an abundance of `little red dots' that look like AGNs (from the paper you cited as well as Kokorev+24 https://arxiv.org/abs/2401.09981, Matthee+23 https://arxiv.org/abs/2306.05448, or Greene+ 23 https://arxiv.org/abs/2309.05714), so it's very likely the ultramassive galaxies that "broke cosmology" are just regular galaxies hosting AGNs, which make them appear red when not modeled correctly!

As an example, the two most massive objects in the Labbé+ paper actually turned out to be AGNs. One of them was spectroscopically followed up in here:

https://arxiv.org/abs/2301.09482

and turned out to have a much smaller stellar mass (source-ID 20 in Table 2 should be one of the big Labbé galaxies). Also Endsley's paper:

https://arxiv.org/abs/2208.14999

Fig 14 they show that there's likely a point source contributing a lot of light. That point source is likely to be an AGN.

Best,

Julian

ENDS…

Thanks again to Marc and Julian B. for letting me show you that peek behind the scenes. Hope you enjoyed it. You can see why it’s taking so long to transition from the old paradigm to the new. A lot of assumptions have to be rethought from scratch. But, it’s happening! Fascinating times…

If all that makes you want to know more about the theory of three-stage cosmological natural selection which is making these excellent predictions, go watch this Youtube primer I did with Jim O’Shaughnessy on Infinite Loops, or listen to it as a podcast on Apple Podcasts, or over on Spotify.

If you haven’t subscribed, please do, it’s free and it means you will be emailed fresh posts as I put them up. And as ever, please do share with anyone you think might be interested.