[HN Gopher] JWST spots giant black holes all over the early univ...
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JWST spots giant black holes all over the early universe
Author : Brajeshwar
Score : 176 points
Date : 2023-08-14 17:26 UTC (5 hours ago)
(HTM) web link (www.quantamagazine.org)
(TXT) w3m dump (www.quantamagazine.org)
| whiw wrote:
| > 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 wrote:
| > 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
| p 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 wrote:
| 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.
| dylan604 wrote:
| What if you have 3.14Pi?
| marcosdumay wrote:
| 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.
| dylan604 wrote:
| sometimes, i wonder if astronomy/physics were to only use
| unsigned numbers, if things would just make more sense.
| you'd get much more precision, and then you wouldn't have
| to worry about "but the math says it's possible" issues by
| taking everything by * -1.
| labster wrote:
| Jesse, what are you talking about?
| pdonis wrote:
| _> 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.
| antognini wrote:
| 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 wrote:
| Well, this is awesome.
| Smoosh wrote:
| Sometimes I despair for humanity [see advertising/social
| media/politics], but then I see something like this and
| think, we're doing pretty well for self-taught primates.
| dylan604 wrote:
| and then we see all of the belief systems to mock,
| punish, or worse people that are trying to expand human
| knowledge. looking back at history, you have to wonder
| where we might be now if there wasn't this attempts at
| mass eradication of learning. there are times i wonder if
| we're heading in that direction again. this time, rather
| than burning the Library of Alexandria or locking
| everything in catacombs, if we're not just trying to get
| there on a low-n-slow approach.
| ajross wrote:
| > 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 LCDM 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 wrote:
| > 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.
| antognini wrote:
| I know Terence Tao (yes, that Terence Tao) is working on a
| book about the cosmic distance ladder, but sadly it's not
| out yet. (I guess he probably has other projects he's
| working on.) But he does have some slides from talks he's
| given: https://terrytao.files.wordpress.com/2020/10/cosmic-
| distance...
| mkoubaa wrote:
| My understanding is that a particles, like photons, don't have
| wave shifts. That's an emergent property of many particles
| alecst wrote:
| 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 wrote:
| No, individual particles can indeed be redshifted. The
| particle's wavelength is a fundamental property.
| tsimionescu wrote:
| 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.
| blueprint wrote:
| 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.
| tsimionescu wrote:
| That is not the current understanding of quantum mechanics,
| as far as I know. Wave/particle dualism says that different
| experiments can either view light as a wave or a particle
| (never both) and that speaking about the nature of light
| when an experiment is _not_ being performed is non-
| scientific by definition.
|
| Importantly, light very much behaves like a conventional
| wave in many real experiments - the interferometer
| experiment being one of the oldest and most well known. It
| is not a probability wave in that case, but an actual
| physical wave (now known to be an oscillation in the
| electro magnetic field, but long assumed to be a mechanical
| wave in the luminiferous aether).
| fpoling wrote:
| Experimentally one never observes waves. Light is
| detected based on its interaction with electrons and that
| is always by an electron absorbing a quanta of energy,
| not via some continuous process as would be the case with
| waves.
|
| Classically one can imagine that as if electron was hit
| by a particle. But then we have light diffraction and
| interference, which classically is described as a wave.
| So from a classical point of view light travels as a wave
| but interact as a particle.
|
| As of nature of the light, then consider that there is a
| reformulation of a classical electrodynamics that
| eliminates electromagnetic waves all together. There are
| only electrons that interacts with each other directly
| with no waves in between. Feynman spent quite some time
| trying to develop quantum electrodynamic based on that.
| He failed. Still the point stands that we never observe
| light directly but only through its effects on electrons
| and other charged particles. So it could be that what we
| call light is a theoretical artifact and there is no
| light in reality.
| jsbisviewtiful wrote:
| 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 wrote:
| 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.
| dotnet00 wrote:
| 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.
| [deleted]
| mvdtnz wrote:
| 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.
| Mistletoe wrote:
| It actually made the story more interesting to me. I like
| learning the human side to the stories.
| [deleted]
| prvc wrote:
| 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.
| ajross wrote:
| 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.
| mvdtnz wrote:
| > 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.
| colechristensen wrote:
| 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.
| forrestthewoods wrote:
| > 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.
| bowsamic wrote:
| 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.
| andai wrote:
| 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 wrote:
| 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.
| teaearlgraycold wrote:
| English text transformation is a task it's exceptionally
| good at. You just need to prompt it to only use the source
| material you give it for summarization.
| atoav wrote:
| "Explain me _something_ , I don't care if it is true, because
| I wouldn't be able to tell anyways"
| burnished wrote:
| I'm not sure this is good advice, especially considering the
| context is around novel material.
| afterburner wrote:
| The universe is draining.
|
| Don't worry, there's still time.
| somat wrote:
| 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 wrote:
| 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?
| cooper_ganglia wrote:
| I knew it wasn't possible, but I'm not smart enough to
| verbalize exactly why. So, I asked ChatGPT! Here is it's
| answer:
|
| "Certainly, it's fun to entertain such a "shower thought" or
| imaginative idea, and though it doesn't align well with our
| current understanding of galactic formation, it's worth
| exploring.
|
| The analog between solar system formation and galaxy formation
| is an interesting one, but there are several key differences
| that make the comparison difficult:
|
| 1. *Scale*: The scale of solar system formation and galaxy
| formation is vastly different, not just in terms of size but
| also in terms of physical processes.
|
| 2. *Gravitational Interactions*: The formation of a solar
| system involves the gravitational collapse of a cloud of gas
| and dust, which leads to the formation of a central star with
| planets and other objects forming from the remaining material
| in a protoplanetary disk. Galaxies, on the other hand, are
| composed of billions of stars, many with their own solar
| systems, along with vast amounts of interstellar medium and
| dark matter. The interactions are much more complex.
|
| 3. *Dynamics*: In a solar system, most of the mass is
| concentrated in the central star, and the gravitational
| dynamics are relatively simple. In galaxies, the mass is
| distributed throughout, and the gravitational interactions are
| influenced by many factors, including the presence of dark
| matter.
|
| 4. *Evolution Time Frames*: As you mentioned, the time scales
| are vastly different. The formation of a solar system takes a
| few tens of millions of years, whereas galaxy formation and
| evolution occurs over billions of years.
|
| 5. *End State*: Your notion of mature galaxies ending up with a
| small number of point masses is fascinating but not supported
| by our current understanding. Galaxies can indeed host
| supermassive black holes at their centers, and galaxy
| collisions may lead to more complex configurations, but the
| idea of galaxies evolving into a "galaxy-sized solar system"
| with a few black holes orbiting each other doesn't align with
| what we know about galactic dynamics.
|
| 6. *Galactic Collisions*: Unlike solar systems, galaxies often
| collide and merge. These interactions can significantly alter
| the structure of galaxies and are an essential part of their
| evolution.
|
| The beauty of a thought like this is that it encourages us to
| think creatively and question our understanding of the
| universe. While this specific idea may not align with our
| current knowledge, it's certainly an imaginative concept that
| underscores the incredible complexity and mystery of galactic
| formation and evolution. It's these types of thoughts that
| often inspire new avenues of scientific exploration!"
| dotnet00 wrote:
| 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.
| claytongulick wrote:
| 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 wrote:
| Scientist recently got a good picture of one
| csours wrote:
| 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 wrote:
| There's been more than one picture of one
| krukah wrote:
| 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
| Zamicol wrote:
| 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 wrote:
| 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.
| javajosh wrote:
| 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.
| nomel wrote:
| [dead]
| vagab0nd wrote:
| > 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.
| throwuwu wrote:
| Partition them by velocity
| ijidak wrote:
| > internally consistent limits on what the player can know
|
| Interesting thought. Can you expand? What do you mean by this?
| r2_pilot wrote:
| 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.
| jancsika wrote:
| Wouldn't it be slightly easier to just, you know, visually
| obscure the opponent's base?
| JumpCrisscross wrote:
| Has anyone re-written a classic RTSG with a slower speed of
| light? Like, Red Alert, but with time dilation.
| r2_pilot wrote:
| Not to my knowledge, but there is a game called A Slower
| Speed of Light, which probably needs no further
| clarification.
|
| https://en.m.wikipedia.org/wiki/A_Slower_Speed_of_Light
| mekkkkkk wrote:
| Wouldn't that be incredibly hard, considering that the
| players perspective is disconnected from the units?
|
| I observe my base and order a group of units to go to
| some place on the minimap. I see them moving along on
| their way, and decide to scroll to them. Only to realize
| that they already arrived and got massacred by the enemy.
| I go back to my base only to realize that it was
| destroyed ages ago (in its frame of reference) and I'm
| dead. Game over. Thanks for playing SR Red Alert.
| xwdv wrote:
| Would be great as an artistic project, maybe not as a
| game.
|
| Also in time I bet some players would find ways to win
| reliably, creating a new field of military strategy.
| JumpCrisscross wrote:
| You'd have to have a HQ relative to which all dilation is
| calculated. If done correctly, it could simplify server
| operations since the need for simultaneity is relaxed.
| vient wrote:
| In ordinary strategies you already have an assumption of
| immediate information transfer from unit to player - you
| see what each unit is seeing. This can be kept so you
| will see you units moving in real time but as things get
| further from your units on the map, the older info about
| them you get.
| mekkkkkk wrote:
| That's interesting. Wouldn't it lead to paradoxes where
| enemy units are shown at multiple places at once,
| observed from different frames of reference? Would be
| incredibly confusing, but confusing games can be fun too.
|
| EDIT: Also if a unit traveled close to C away from a
| friendly unit, and then back, whos reference is real?
| vient wrote:
| Observations merging is interesting question. Simplest
| thing to do may be to show enemy unit as it is seen by
| our unit closest to them (here we just use "real"
| distance in internal game's coordinates). In other words,
| Voronoi diagram is built with our units as seeds, and
| enemies are shown as seen from their cell center. This
| would evade enemy "phantoms" but enemies can suddenly
| "teleport" as they move closer to other friendly unit (or
| can't they? I don't really know).
|
| In lore it may be explained like "our units know
| distances to objects and choose closest one among all
| units" since we already use "units can communicate
| instantly" magic.
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