JWST spots giant black holes all over the early universe

https://www.quantamagazine.org/jwst-spots-giant-black-holes-all-over-the-early-universe-20230814/

by Brajeshwar • 3 years ago

362 177 3 years ago

whiw• 3 years ago

Galactic spectra, which JWST started to send back in earnest at the end of last year, are useful for two reasons.
First, they let astronomers nail down the galaxy’s age. The infrared light JWST collects is reddened, or redshifted, meaning that as it traverses the cosmos, its wavelengths are stretched by the expansion of space. The extent of that redshift lets astronomers determine a galaxy’s distance, and therefore when it originally emitted its light.

Won't a photon climbing out of a huge gravity well have a huge redshift, thus confounding estimates of distance from us and estimated age?

ben_w• 3 years ago

Won't a photon climbing out of a huge gravity well have a huge redshift,

Yes

thus confounding estimates of distance from us and estimated age?

Not if you know, or can get a good estimate of, the potential well it's climbing out of.

That said, Brian Cox does sometimes joke that astronomers round π to 1; while I wouldn't know about the reality, it's probably safe to infer at least some frustration on his part about the precision of things in this field.

hutzlibu• 3 years ago

I also don't know how accurate that description is, but this comic comes to mind:

https://xkcd.com/2205/

But I mean, space is really, really big and we are observing from one single spot with (on cosmological scale probably) primitive technology. So of course most of it is guessing and when you "guess" a lot of things, it maybe does not matter a lot, if you have 3.41 Pi or 1, when the data you have are rough estimates anyway. But sure, when you do sloppy math, when you could have precision - that would be just wrong and unscientific.

marcosdumay• 3 years ago

The joke was way more true at the 20th century. There were many really important measurements where we got unprecedentedly precision, enough to say it's X, 100X, or something in between.

Nowadays astronomy got a lot more precise. But there are disagreements on how much confidence to put on that extra precision.

quickthrower2• 3 years ago

I was confused... the symbol π is actually Pi, but it renders as something that looks like a different alphabet entirely on HN.

gpgn• 3 years ago

These are somewhated dated but well worth watching; the professor does all kinds of approximations.

Frontiers/Controversies in Astrophysics with Charles Bailyn: https://youtu.be/ZiK4lg3Tzfs?t=1628

mkoubaa• 3 years ago

My understanding is that a particles, like photons, don't have wave shifts. That's an emergent property of many particles

alecst• 3 years ago

The conventional Doppler shift and the equivalence principle imply a gravitational redshift for a photon. See page 102:

https://preposterousuniverse.com/wp-content/uploads/grnotes-...

stopping• 3 years ago

No, individual particles can indeed be redshifted. The particle's wavelength is a fundamental property.

blueprint9• 3 years ago

Your comment is a bit strange. Light doesn't travel as photons. Photons exclusively exist at the site and instant of detection of the wave of probability of detection that light really travels as.

When light is redshifted, it loses energy, therefore the wavelength becomes longer.

tsimionescu2• 3 years ago

In quantum mechanics, a single particle is also a wave and vice versa. Light is in fact the thing where this observation was first discovered - it had been proven to be a wave for at least a few decades when Einstein discovered the quantum nature of the photovoltaic effect, proving it is also a particle. This discovery was the very start of quantum mechanics, in fact.

pdonis• 3 years ago

Won't a photon climbing out of a huge gravity well have a huge redshift

It depends; the key factor is not how "huge" the gravity well is (in terms of how massive the object is), but how close to the black hole horizon the light is emitted. The vast majority of the light JWST is seeing from black holes is not from very close to the horizon. It's from the accretion disk, which is much further from the horizon and so the gravitational redshift is much smaller.

ajross2• 3 years ago

Won't a photon climbing out of a huge gravity well have a huge redshift, thus confounding estimates of distance from us and estimated age?

Of course it will. It will also have a redshift related to the expansion of the space it's been travelling through. Both of those corrections are absolutely part of the model. It's not nearly as simple as "Astronomers forgot about General Relativity!".

But I guess it's true (to be clear: I'm just an amateur in this field) that the ΛCDM model for cosmological evolution that we've all been looking at for the past decade or two isn't holding up well at all. It looked like it was pretty much there and just needed some fine tuning. Then we got a bunch of new data and everything's a mess.

That's kind of exciting all by itself, though it's also leading to a bunch of nattering from the existing iconoclasts (MOND nuts in particular) whose theories are also not working very well to explain JWST observations.

New insight needed, basically. We're all watching for updates.

xigency• 3 years ago

Both of those corrections are absolutely part of the model

Is there a way to gain a better understanding of how these parameters are modeled and what the scientific evidence is for the various phenomena in astrophysics? It's somewhat perplexing to me as an outsider of the field to understand how things like mass and distance of stars and planetary bodies are determined when 1) the scales are so outside of conventional experience 2) observation is limited to 2D imaging of the night sky 3) the observations in general are not consistent with our knowledge of gravity and relativity without adding hidden parameters.

antognini2• 3 years ago

The photons that are getting observed are emitted from the accretion disk, which is not very close to the event horizon.

You can estimate how close to the event horizon the disk is based on how broad the spectral lines are. The part of the disk that is coming towards you will be blueshifted and the part of the disk that is rotating away will be redshifted. From that (which is independent of the overall depth of the potential well) you can figure out how fast the disk is rotating. And from that you can figure out how far away the disk is from the black hole.

quakeguy• 3 years ago

Well, this is awesome.

codethief3• 3 years ago

Won't a photon climbing out of a huge gravity well have a huge redshift

Yes. Though see the sibling comments on why the (remaining) gravity well the emitted photon has to climb out of is not particularly huge here.

thus confounding estimates of distance from us and estimated age?

Generally speaking: No, because people are not stupid. :) See the integrated Sachs-Wolfe effect for a very similar situation (CMB photons traveling through gravitational wells) -> https://en.m.wikipedia.org/wiki/Sachs%E2%80%93Wolfe_effect

javajosh3• 3 years ago

This is super cool. I think it's funny how Quanta writes, "It is expected because JWST was built, in part, to find the ancient objects." "Ancient" is equivalent to "distant" because of special relativity. It's an odd thing, astronomy - it's a real world time-traveling observation, except we're limited in resolution and we can't look here only there. If it was a game mechanic I'd call it a cunning way to impose internally consistent limits on what the player can know.

ijidak• 3 years ago

internally consistent limits on what the player can know

Interesting thought. Can you expand? What do you mean by this?

r2_pilot2• 3 years ago

Not the original author but my first interpretation is that this means, if it were in a video game, it would be a way to self-reinforce "fog of war" where you can only have extremely local information and you don't want extra information to leak to the players.

javajosh3• 3 years ago

Sure. I expanded in another comment: https://news.ycombinator.com/item?id=37128472

nomel• 3 years ago

Ancient" is equivalent to "distant" because of special relativity

This is from the finite speed of light, not special relativity [1]. Light is very slow, compared to these distances. Heck, it's slow compared to distances in our solar system, taking 8 minutes for the Sun's light to hit us.

[1] https://www.wtamu.edu/~cbaird/sq/2014/10/23/how-does-looking...

vagab0nd2• 3 years ago

If it was a game mechanic I'd call it a cunning way to impose internally consistent limits on what the player can know.

But if you assume it's a multi-player game, wouldn't it be easier to implement a global space-time? The reality is that you have to keep an internal clock for each player.

throwuwu2• 3 years ago

Partition them by velocity

javajosh3• 3 years ago

In practice you need a global coordinate system. For example, you'd create a "spawn point" for all players, and then, before the game starts, move them to their starting positions at a fraction of c. The game is still keeping track of units within this initial coordinate system, and transform those coordinates for the player. The reverse is done for player decisions. There is effectively an in-game "star network" that mediates between player. Each player/unit has a unique light cone associated with it.

Nothing stops us from arbitrarily designating a particular reference frame as "preferred" in a simulation; SR merely says that such a choice is truly arbitrary. Note also that this system could work recursively, such that new units must always spawn at the spacetime location of older units, and do information management (behind the scenes) in a similar way. This would turn the network into a tree - and the transforms are relatively cheap (and we could use a Spacetime algebra library!)

Note that I don't think this works for a traditional RTS like C&C or Supreme Commander. But rather a game like Civilization, but galaxy spanning (and spanning very long periods of time), where the smallest objects are something like "suns" and "fleets". The individual lives of humans would come and go as these vast battles took place over thousands of years. You'd only need to add magic like a 1g constant acceleration drive - and a strong rule against using this to directly kill planets - and assume that the fleets are actually large-ish asteroids fitted with the drives and a human and/or robotic crew.

The spawn point would then be, fittingly, Sol.

mr_toad3• 3 years ago

The reality is that you have to keep an internal clock for each player.

You can transform between two players clocks easily enough. Time is just another coordinate to maintain.

https://en.wikipedia.org/wiki/Lorentz_transformation

antonvs3• 3 years ago

"Ancient" is equivalent to "distant" because of special relativity.

You don't need special relativity for that, all you need is a finite speed of light - a fact which was known before special relativity was developed.

mvdtnz2• 3 years ago

I wish stories like this were a more straight forward counting of the interesting facts and relevant input from experts. I don't really need the origin story of the conference this finding was discussed at.

andai2• 3 years ago

You can ask GPT to rewrite it according to your preference. (Not being facetious: I often ask it for bullet points or "explain like I'm 13.")

louislang• 3 years ago

the problem with GPT is that you're not guaranteed to get something that's _accurate_. I'd definitely prefer some input from an expert over GPT.

burnished• 3 years ago

I'm not sure this is good advice, especially considering the context is around novel material.

atoav• 3 years ago

"Explain me something, I don't care if it is true, because I wouldn't be able to tell anyways"

ajross2• 3 years ago

The stuff you're complaining about seems limited to a little bit of POV text in the first seven (!) sentences of a rather long article. Does it really bug you so much that they gave you just a tiny taste of the perspective of a woman who works on this stuff? That seems a bit much. This kind of text is everywhere in science journalism.

forrestthewoods• 3 years ago

of a rather long article

I utterly despise the current “long form” style where all long form stories start by talking about something old and unimportant.

Sure it’s a nice appetizer to whet the palette. But only if I already know I’m gonna read the whole thing! There’s too much long form for me to read. I want a tastier first bite to see if it’s worth my time.

I blame the New Yorker. Bastards.

colechristensen• 3 years ago

I likewise do not like the front loaded flavor text.

A good news article should be written in order of priority. Each word, each sentence should be written in order of decreasing priority starting with the headline. "JWST spots giant black holes all over the early universe" is a great headline, it encompasses the entire story. Especially at the beginning of the article, the purpose should be expand and clarify the most important pieces.

I really dislike the kind of journalism that goes into biography mode and starts off with an anecdote about Jane Einstein's childhood dog leaving the most relevant bits 2/3 the way through.

I'd like to be able to choose the level of detail I get from an article by being able to stop when I'm done.

I don't like having to dedicate several minutes to finding a piece of information that took several seconds to deliver. Much like the 10 minute youtube howto video hiding the five seconds of information I needed.

mvdtnz2• 3 years ago

Does it really bug you so much that they gave you just a tiny taste of the perspective of a woman who works on this stuff?

Well, yes, that's why I wrote my post.

This kind of text is everywhere in science journalism.

Indeed.

bowsamic• 3 years ago

I agree. I feel like they are taking "story" too literally now. Science news is soon approaching the level of superfluous meandering of online recipes. I'm not saying I don't care about the context, but a news article should be different to a short story. And, I still think there is a place for these things, but not for all articles, only some.

Mistletoe• 3 years ago

It actually made the story more interesting to me. I like learning the human side to the stories.

prvc• 3 years ago

The first spate of articles from this publication were like this, which really made it stand apart from the others. Somehow a complete inversion has taken place since then.

somat2• 3 years ago

So this is one of them "shower thoughts", you know, those stupid things you think about while working on something else.That is, purely science fiction.

Can an analog be drawn between galaxies and solar system creation theories, with several orders of magnitudes in time required for formation due to scale difference. That is, the galaxies we see with their billions of stars are actually young proto accretion disks. while mature galaxies will have most of the mass localized in a small(1-2) number of points with a few(~10) point masses orbiting it. a sort of galaxy sized solar system if you will. However due to the scale of things involved all these late stage point masses would be black holes.

deanCommie• 3 years ago

I'm here for shower thoughts-driven discourse.

But I missed the point. Stars eventually wind up as black holes. So it stands to reason so would galaxies.

But then why would they be all over the early universe?

consilient5• 3 years ago

Stars eventually wind up as black holes.

The vast majority of stars will end up as white dwarfs. Stars need to be about 10 times the mass of the sun to undergo core collapse, and about 25 solar masses (or more, depending on composition) to form black holes.

So it stands to reason so would galaxies.

Galaxies are loosely bound clouds of dust with a few stars here and there, relatively speaking; stars are dense roiling balls of plasma. Their dynamics are extremely different.

mr_toad3• 3 years ago

But then why would they be all over the early universe?

Stars can form quite quickly (relative to the age of the universe), possibly as early as 150 million years after the Big Bang. And the earliest massive stars would have had very short lifespans.

dotnet003• 3 years ago

It is worth considering that a black hole's hold on its galaxy is not as strong as a sun-like star's on its accretion disk. Our Sun is 99% of the mass of the solar system, our Sagittarius A* is ~4 million solar masses, while our Milky Way is 800 billion solar masses.

On top of that, black hole growth rate slows to nearly a stop at ~270 billion solar masses, so even if a black hole manages to meet the rare conditions to get that heavy, it would still be dwarfed by its galaxy.

Moldoteck2• 3 years ago

Is the upper limit due to hawking radiation?

brabel2• 3 years ago

But at the same time, I think it's been shown the the size of a galaxy almost always reflects the size of its central black hole... that is, the influence of the central black hole seems to be way, way bigger than what you would expect from the black hole's gravity alone.

Laremere• 3 years ago

Not an astronomer, but there's at least one important thing to consider:

Stars form in denser regions of gas. However once they grow large enough to start fusion, the solar wind will blow away the gas, halting growth of that star system. So stars have a kind of limit when it comes to size.

That's what makes these early universe large black holes problematic (read, exciting new science): we know black holes the mass of stars can form by a super nova. However the only way we know that these super massive black holes can form is by smaller black merging. There's simply not enough time for black holes as large as we think jwst has seen to form in the age of the universe we think we're looking at. Something in the physics has to give.

Keysh3• 3 years ago

... the only way we know that these super massive black holes can form is by smaller black merging.

The main way supermassive black holes in the centers of galaxies grow is by accreting gas, not by mergers with other black holes. (But you can still have potential problems with not being able to accrete enough gas in a short enough time to explain early SMBHs, unless the initial "seed" BHs are larger than those formed by conventional supernovae.)

jsbisviewtiful• 3 years ago

It's pretty cool how much JWST has caught in such a short amount of time. Give it another 5-10 years and we may have some absolutely groundbreaking new celestial theories.

mabbo• 3 years ago

It's really worthwhile to compare it to the hubble in that regard.

Pre-hubble, the question was whether the universe would contract into a big crunch, expand slower and slower forever, or balance out somehow in the middle. Then hubble got a good look at universal expansion and we noticed it was speeding up and now we've got Lambda-CDM from that.

From this we know what the long term fate of the universe is. That there are galaxies we can see that but we can never reach. That the universe will end from the slow burn out of heat death and not return to the singularity.

Just imagine what we'll know after 5-10 years of JWST.

dotnet003• 3 years ago

Heat death is one of the possibilities, but it's still very much an open question, as it depends on the curvature of the universe and the nature of dark energy.

tadfisher• 3 years ago

If conformal cyclic cosmology is to be believed, heat death is indistinguishable from the singularity as entropy is infinite in both cases, so heat death "may as well be" the singularity.

afterburner• 3 years ago

The universe is draining.

Don't worry, there's still time.

claytongulick7• 3 years ago

Can someone who really knows this stuff clarify my understanding?

I've been given to understand that black holes remain a physics theory that has not been directly observed or proven.

I thought that we had a fair amount of observational evidence that suggests their existence, but no "smoking gun" proof of it, and that these types of "observed a black hole" articles are a little misleading - that in reality, what was observed was much indirect, interpreted data that is consistent with black hole theory, but could also be something else.

Am I off base here?

thehappypm• 3 years ago

Scientist recently got a good picture of one

claytongulick7• 3 years ago

See, this is my beef with the reporting on this stuff and the source of my question.

The "photo" you're referring to was constructed by a super computer massaging enormous amounts of data to fit a model and constructing an image from weighted averages of thousands of data images across the spectrum from an enormously complex array of detectors in an unfathomably noisy environment [1].

It was presented by the media as a "photo", but it seems to me like it's more similar to the "image" we get from reconstruction of wifi signals in a room to determine interior object's shape.

Or maybe a better example would be the "photos" of atoms, which are not photos at all but a reconstruction of miniscule electromagnetic resistance readings from a STM whisker driven by a piezoelectric crystal.

I think we're supposed to get the ability to have better "photos" with the activation of LISA in 2037 [2] but until then, claiming that we have photos of black holes seems a bit misleading (not by you, I mean the science reporting).

[1] https://eventhorizontelescope.org/blog/astronomers-reveal-fi...

[2] https://en.m.wikipedia.org/wiki/Laser_Interferometer_Space_A...

csours• 3 years ago

As far as I know, the existence of black holes is accepted by basically every astrophysicist.

There are several smoking guns:

https://en.wikipedia.org/wiki/Black_hole#Observational_evide...

Larrikin• 3 years ago

There's been more than one picture of one

krukah• 3 years ago

The theoretical prediction of black holes dates back to 1916, when Karl Schwarzschild proposed a solution to Einstein's field equations that were part of his general theory of relativity. General relativity is arguably the most robust theory in physics - that being said, general relativity introduces some tension with the other most robust theory in physics, namely quantum mechanics and the Standard Model. These two theories are largely accepted to be accurate and correct, and since they predict different phenomena at different length scales, most scientists have no trouble subscribing to both.

With respect to "direct observation" of a black hole, astronomers at the Event Horizon Telescope successfully reconstructed pictures of a black hole using light in the visible spectrum. But to be fair, this comes after decades of overwhelming experimental evidence of black holes + GR. The EHT result probably received the media attention it did because it is easily interpretable as nice lil JPEG, rather than a 12-page paper with dense plots and LaTeX.

See https://en.wikipedia.org/wiki/Tests_of_general_relativity

claytongulick7• 3 years ago

I'm familiar with the indirect evidence, and there's a lot of it.

This article [1] seems to affirm my understanding that this is still all indirect evidence until LISA becomes operational.

[1] https://www.science.org/content/article/after-decades-effort...

Zamicol• 3 years ago

Einstein didn't think black holes existed (1916) and it took until 1971 with Cygnus X-1 for serious consideration, which was the smoking gun. 55 years of being considered probably a math fluke and then observational evidence.

funnymony• 3 years ago

I’ve read something like: there are bunch of observations of extremely dense masses in various suroundings. Talented people can find explanations other than black holes in each case. But that feels adhoc, and black hole fits quite nicely for whole class of observations. Current consensus is that b holes exist.

claytongulick7• 3 years ago

Current consensus is that b holes exist.

I don't think it works like that?

My read from looking at the literature is that the feeling is more like "black holes are a mathematical theory that have not been falsified by observational evidence, and for which we have some compelling, but inconclusive data, reconstructed from intensely noisy and poor resolution sources. Seems likely, but more data needed."

Chabsff• 3 years ago

I think you are confusing Black Holes with Hawking Radiation . The later's status is basically exactly as you describe.

badrabbit2• 3 years ago

I've wondered how blackholes have a similar 2d shape as with hurricanes and whirlpools where the center is empty. What if the inside of a blackhole is devoid of all things including spacetime, although that doesn't make good scifi.

andrewflnr7• 3 years ago

I believe this actually is one of the hypotheses about black hole interiors, though I forget the name. Nothing to do with terrestrial storms or vortices, though; a black hole doesn't have to have any rotation at all.

AnimalMuppet4• 3 years ago

There are rotating black holes (https://en.wikipedia.org/wiki/Rotating_black_hole).

badrabbit2• 3 years ago

Cool.

a black hole doesn't have to have any rotation at all.

How about the gravity or hawking radiation it emanates. I am actually surprised that matter falling into a blackhole isn't whirlpooling around it.

hxegon2• 3 years ago

A part of CCC[1] is giant black holes outlasting the end of the universe to be around for the beginning of the next one. Is this a potential explanation?

[1] https://en.wikipedia.org/wiki/Conformal_cyclic_cosmology

searealist• 3 years ago

In CCC, black holes all evaporate before that.

hxegon2• 3 years ago

Do they? One of the papers in support of CCC found patterns in the CMB that might have been black holes remaining from the last cycle. I wonder if they'd start eating the new matter created by the big bang and survive.

marcus_holmes• 3 years ago

Over the course of a year, Chandra stared at the cosmic lens for two weeks — one of its longest observation campaigns yet — and collected 19 X-ray photons coming from a galaxy called UHZ1, at a redshift of 10.1. Those 19 high-octane photons most likely came from a growing black hole that existed fewer than half a billion years after the Big Bang, making it by far the most distant X-ray source ever detected.

This blew my tiny mind.

19 photons over 2 weeks. That's such a tiny amount of light. How are we able to conclude anything from such tiny amounts of light? (I'm not disputing that we can, it just blows my mind that we can).

And those photons - 13+ billion years speeding through space, all that vast empty time and distance, to end up hitting a detector during those two weeks when doing so will change the way we think about the universe. And of course the photon itself hasn't experienced any of that time. For the photon, it was all the same moment.

Also blows my mind that any time I'm standing outside I'm being hit by photons that have been traveling for billions of years to reach that point. Of course they're overwhelmed by photons from the Sun, but still. Some photon left a sun billions of years ago, sped through the universe for all that time, and ended up hitting my retina. And I don't even realise when this happens.

I understand why theists don't like science. How can your puny god compare to shit like this?

mr_toad3• 3 years ago

You used to be able to tune a TV between channels and listen to the hiss of the cosmic microwave background. That’s light from millions of years before the first stars.

Digital TVs just don’t have that 2.73 degrees above absolute zero sound to them.

mikeInAlaska• 3 years ago

Now imagine that the Chandra telescope has a 1.2 meter diameter aperture that those 19 photons passed through.

That represents 1.13 square meters of light collecting area, peering into that expanding spherical wavefront at the point where it is 26+ billion light years in diameter.

That would be a sphere with a surface area of 2,123 square light years. I wonder what it would add up to if you had the 19 photons for all those other 1.13 meter chunks of area in one place.

sinuhe692• 3 years ago

Maybe I’m a bit naive here, but I thought finding of many supermassive back holes in the very early universe should be expected, and not a surprise. My chain of thoughts is following:

- Blackholes are collapsed masses. In our phase of the universe, they are normally the results of supernovae but only because today stars are the only source of dense masses.

- Because the total mass of the universe is constant and the early universe has a volume of dozen orders of magnitude smaller than the universe in later stage (the universe we normally observe), collapsed masses should happen much more likely than in later stage.

- Those masses do not necessarily come from the stars, which are masses with a visible fusion processes but could come directly from mass-lumps, left after the Big Bang.

- In fact, I think the idea of a super homogenous universe right after the Big Bang is suspect. Even the CMB is only homogeneous on (very) large scale (3000 mega parsecs), ways too big for blackholes.

- Therefore, I think after the Big Bang, there should be a large number of primordial blackholes.

- We can only observe blackholes with an accretion disk, but the primordial blackholes with no visible accretion will stay invisible unless there is a collision/fusion in progress.

Consequently, we will find a lot more blackholes in the early universe, the more we look. They are super massive because of the bias: only supermassive blackholes with accretion disk were producing radiation, powerful enough so we can detect with our current technology.

andrewstuart• 3 years ago

Great ideas tend to be obvious in hindsight.

lenkite• 3 years ago

Lets say the number of actual black holes is even more - several orders more than what is even mentioned here.

Would it be enough to account for the "Dark Matter" conundrum ?

sinuhe692• 3 years ago

In fact, primordial blackholes are a candidate for dark matter hypothesis. They are still invisible but at least we could devise a theory to detect them (light focusing/bending for examples)

andrewflnr7• 3 years ago

Look up the "MACHO" hypothesis for dark matter. Tl;dr: mostly ruled out via gravitational lensing surveys.

mikhailfranco• 3 years ago

There remains doubt about CMB inhomogeneity at the smallest scales - basically the error bars at the right of this graph, and the region off the chart to the right, which is yet to be measured:

https://en.m.wikipedia.org/wiki/Cosmic_microwave_background#...

A naive view would be that a turbulent Big Bang has turbulence all the way down, with many fine-grain clumps and vortices, giving rise to early black holes.

Inflation is invoked to create a homogeneous CMB, but that begs the question, and cannot be used to rule out small-scale inhomogeneities.

netbioserror2• 3 years ago

This makes a lot of sense. In those first few seconds, that incredibly hot, dense soup of matter would've immediately "pitted" through with absolutely enormous black holes, and like rain, those black holes were probably the "seeding" nuclei for the remaining matter to clump around and form galaxies. Which suggests that galactic core supermassives are drifting leftovers from the formation of the universe. It might also suggest that after the primordial age, they may not have consumed much matter at all (though we have plenty of evidence of some early supermassives consuming quite a lot at the fringes of the observable universe).

MaxikCZ• 3 years ago

I still dont get it. If during the first few second there was so much matter in so little space that enormous blackholes should form, then why did big bang even happen? In the first instance, there was all the matter in the tinies of space, everything should have immediatelly form a blackhole and bigbang should have not happen

dtgriscom• 3 years ago

What do you mean by "many" black holes being "expected"? What's "many"?

You have to be specific, and to do that you model, and then validate through observation. The article states that more black holes are being observed than the models predict, which is their definition of "many".

tzs• 3 years ago

Because the total mass of the universe is constant

It isn't [1]:

The point is pretty simple: back when you thought energy was conserved, there was a reason why you thought that, namely time-translation invariance. A fancy way of saying “the background on which particles and forces evolve, as well as the dynamical rules governing their motions, are fixed, not changing with time.” But in general relativity that’s simply no longer true. Einstein tells us that space and time are dynamical, and in particular that they can evolve with time. When the space through which particles move is changing, the total energy of those particles is not conserved.
It’s not that all hell has broken loose; it’s just that we’re considering a more general context than was necessary under Newtonian rules. There is still a single important equation, which is indeed often called “energy-momentum conservation.” It looks like this:

     μν
  ∇ T  = 0
   μ

> The details aren’t important, but the meaning of this equation is straightforward enough: energy and momentum evolve in a precisely specified way in response to the behavior of spacetime around them. If that spacetime is standing completely still, the total energy is constant; if it’s evolving, the energy changes in a completely unambiguous way.

In the case of dark energy, that evolution is pretty simple: the density of vacuum energy in empty space is absolute constant, even as the volume of a region of space (comoving along with galaxies and other particles) grows as the universe expands. So the total energy, density times volume, goes up.

[1] https://www.preposterousuniverse.com/blog/2010/02/22/energy-...

kune• 3 years ago

The density of black hole decrease by the inverse square of the mass of the black hole. That means massive black holes have a much lower density that small black holes. So they are more likely to form than small black holes. Dark matter will have played an important role in the creation of those early black holes. If there is no dark matter and some form of MOND theory of gravity is correct, the Schwarzschild formula will require a modification for large black holes. In that case galaxy centers will not require large masses to see the same effects.

whimsicalism• 3 years ago

So they are more likely to form than small black holes.

Based on your previous sentence would it not be the opposite?

micw• 3 years ago

What exactly is the "density" of a black hole?

As I understand, a BH is a singularity, so all mass is at one point which means all BHs have the same (infinite) density.

Is it a kind of "virtual density", e.g. the mass of the singularity devided by the schwarzschild radius or the event horizon?

zycon• 3 years ago

Density is mass divided by volume. Volume of BH is defined by event horizon.

Singularity is a result of applying a theory of relativity in a case where we know relativity doesn't work, so it's unlikely it's real.

codethief3• 3 years ago

I suppose OP defines it as the mass of the BH, divided by the apparent volume taken up by the BH (more precisely: the apparent horizon), as seen from the outside. Put differently, for a Schwarzschild BH: Density ~ M/R³ (modulo constant prefactors) ~ 1/M², since the Schwarzschild radius is linear in M.

sebzim45002• 3 years ago

So they are more likely to form than small black holes.

This certainly does not follow from the rest of your comment. I'm pretty sure it's false.

KolenCh• 3 years ago

They may have included the effect of black hole evaporation here? Small black holes evaporates much quicker and won't survive.

AnimalMuppet4• 3 years ago

I think the claim is like this: You have the primordial universe, shortly after the big bang, with fluctuations in density. But the whole density is very high. A fluctuation over a large region could put the region over the threshold to become a black hole, because the density required for that to happen is lower than for a small region.

Mind you, I don't know if this actually works. What was the density of the early universe, compared to the density required to form a black hole? How large were the fluctuations? Is this scenario plausible at all?

I suppose that if you go back close enough to the big bang, then you can get a density high enough. But then, if you go back not much farther, shouldn't the whole universe have formed a black hole? And if it didn't, can we trust the logic that says that the situation should have led to the formation of giant black holes?

Keysh3• 3 years ago

That means massive black holes have a much lower density that small black holes. So they are more likely to form than small black holes.

No, it doesn't, because you're ignoring all the physics required to get the mass into a small enough region so that it will collapse to form a black hole. The only way to make that happen that we know works is to form massive stars, where a fraction of the star's mass, in the center of the star, will eventually form a black hole. But the largest stars we know of have masses of ~ 200 times the Sun, and so can't form black holes more than a fraction of that.

If you imagine a more massive gas cloud collapsing under its own gravity, it will fragment into subclumps before getting very dense; these subclumps will themselves fragment or go on to form stars directly, but with an upper limit of, say, ~ 200 solar masses.

(It's possible that if you start with a cloud of pristine gas in the early universe -- nothing but hydrogen and helium -- that it might collapse to form a single supermassive star, or even a black hole directly. That might give you something like a 1000-solar-mass black hole. But that's still fairly speculative, and requires unusual conditions that don't exist generally.)

FreshStart• 3 years ago

So if it's equally distributed matter antimatter at the start, what are these holes made off?

scotty79• 3 years ago

My belief is that all supermassive black holes are primordial. They were "seeds" of the galaxies from the start.

JWST spots giant black holes all over the early universe

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