UHZ1: NASA telescopes discover record-breaking black hole
chandra.si.edu
chandra.si.edu
We've spotted strong evidence for a supermassive black hole (of the kind that tend to sit in the center of galaxies like ours, which contains Sagittarius A*) in an extremely distant galaxy - one that formed within the first half-billion or so years of the galaxy.
What makes this important is that we've seen increasing evidence that supermassive black holes (SMBHs) exist earlier than we've expect if they were born from the deaths of massive stars and slowly accumulating mass in the way "typical" black holes today do.
This black hole is apparently very good evidence that these early SMBHs did not form from star collapse but may have formed from gas clouds collapsing directly into black holes. Finding support for this alternative model could lead us to new possibilities in physics.
Universe?
Galaxies were still being created much after the Big Bang and the universe coming into existence.
I don't think he has any math to back this up. In his theory, it just… happens.
Not to mention if supermassive black holes were being formed by accretion, you would expect to see many intermediate mass black holes (1000-1000000 solar masses) everywhere, but we see almost none.
Either what we know about black hole formation is basically complete (it goes gas -> star -> black hole -> accretion + collisions) but the environment in the early universe was sufficiently different/dense that parameters which rule out the formation of supermassive black holes now were different. Maybe there were many intermediate black holes just in the millions of years after the big bang and things were still close enough together that accretion could happen and collisions were "likely" at the rate needed to form SMBHs after just a billion years. If that is true we might expect to see many many active galactic nuclei as we get better telescopes and look further back, depending on how quickly such black holes formed.
The other option is there is a mechanism of black hole formation that bypasses the above chain which we understand. People talk about supermassive stars, gas clouds collapsing directly into black holes, or primordial black holes that existed due to essentially random distributions of density moments after the big bang causing some regions of space to collapse into massive black holes which then persisted. Such things are far more difficult to observe, but could be inferred if we don't see many many active nuclei as we get better telescopes but all other indications of the accuracy of the big bang + inflationary theory hold true.
Why do we assume mass distribution in the early universe followed a regular pattern? We can't explain why the universe isn't isotropic and we can't explain why there's more matter than antimatter so why couldn't there have been clumps of very dense matter ready-made to collapse into a black hole?
This in turn puts constraints on the primordial quantum fluctuations that were inflated during the inflation phase, and backtracking through simulations it puts constraints on the entire dark matter and matter history from now back to age 380,000 years.
I'm no expert, but wouldn't it make sense that in a non-uniform expanding explosion, the densely packed areas would behave the way density behaves? If the universe expands over time, isn't it denser near the beginning, allowing large scale density events to take place early in time? Couldn't a dense universe have allowed supermassive stars to form that just immediately collapsed?
It's cool to discover it or anything else, but I'm not clear on why we should be surprised?
Article reports some new evidence that seem to support it.
Not every seemingly obvious hypothesis is true.
My personal favourite at-first-counterintuitive law of nature: in orbital mechanics, to catch-up, speeding-up does not work. Speeding up (1) changes the orbit, (2) elevates the orbit, (3) higher orbit has lower speed. (Excluding trivially close distances)
> mass falls between 10 and 100 million suns
The size of the sun already causes my brain to shut down. Everything about this is beyond contemplation.
From the article:
> The extremely distant black hole is located in the galaxy UHZ1 in the direction of the galaxy cluster Abell 2744. The galaxy cluster is about 3.5 billion light-years from Earth. Webb data, however, reveal that UHZ1 is much farther away than Abell 2744. At some 13.2 billion light-years away, UHZ1 is seen when the universe was only 3% of its current age.
In fact Earth might survive (as an ice planet) much longer than it would around the Sun since the Sun is expected to become a red giant and possibly swallow the Earth when it dies.
And as a motivator for both our intellectual curiosity and our scientific curiosity, the lack of a detailed moon in our night sky would have retarded the development of human civilization.
One could argue that Plank length is not the most best lower limit.
It turns out, as beings living in the 10^0m scale, we are much closer to the size of the universe 10^27, than to the smallest possible distance, 10^-35.
Which boggles my mind, I did not imagine the Planck length to be this small, if it even makes sense to use the word "imagine".
It has nothing to do with smallest possible length or something like that and it's just a common mistake in non-scientific physics articles that has sadly spread.
This intuition does not work in curved spacetime, particularly not for black holes. Black holes do not even have a well-defined volume at all.
I was uncomfortable with the conflation of the "volume of a black hole" with the volume of that sphere.
...is not what a black hole is. It is not even "something kinda sorta like a sphere with some Schwarzschild radius". It is nothing like any ordinary object you're used to. It doesn't have a well-defined "radius" any more than it has a well-defined volume; the Schwarzschild "radius" is actually sqrt(A / 4 pi), where A is the surface area of the hole's horizon (which in turn is calculated from the mass of the hole).
This is relevant to the discussion at hand because for these very large black holes that density is not very high and conceivably a gas cloud of sufficient mass could contract to that density and have an event horizon form without collapsing into Stars.
No, it doesn't. There are indeed upper limits on the mass of objects that are formed from stars that run out of nuclear fuel, before the objects collapse to black holes (the Chandrasekhar limit for white dwarfs and the Tolman-Oppenheimer-Volkoff limit for neutron stars), but those limits are not based on density.
It is true that, especially in the early universe, gas clouds forming very massive black holes without going through the intermediate stage of forming stars is considered possible; but that is not based on the kind of simplistic calculation that you describe. It's based on numerical simulations of the Einstein Field Equation with relevant initial conditions.
Another factor you are not considering is that the universe is expanding, and the early universe was expanding much more rapidly than our current universe is. So gas clouds contracting to form very massive black holes had to work against the expansion to do so. That further complicates the calculations.
Is that correct? My understanding is that the expansion of the Universe occurs away from large concentrations of mass; expansion doesn't cause the stars in a galaxy to move apart.
What does that mean? The Schwarzschild radius is just the distance at which even light can no longer escape, the only matter there is the matter that happens to be falling in at that moment. Unless you mean the average density within the Schwarzschild volume (a term I just made up as far as I know, but you know what I mean) if all the mass of the black hole were spread out evenly throughout it.
That seems like a weird condition. "Average density" is pretty well-defined and doesn't need even spreading.
Even more, isn't the distribution of mass within a black hole a meaningless question? There's no information coming from the black hole, for an external observer it literally doesn't matter how the matter is arranged within.
A rotating (or merging) black hole can be deformed (non-spherical), but that doesn't stop you to calculate average density.
It's not really separate, because more things can fall in.
It's also not really separate if black holes may evaporate, in part because it is the outside conditions that determine when (and even if) evaporation begins. There are unsettled questions about whether black holes, even given suitable exterior conditions, fully evaporate; and exactly how to connect what fell into the black hole with what's left after complete evaporation. However, it is the mass inside that gives rise to Hawking radiation outside, so there is some connection.
Otherwise I think you're quite right, particularly about the gentleness of the Weyl curvature (the tidal part of the Riemann curvature tensor) around the event horizon of a large black hole.
"Pass through the event horizon, alive" is the "no-drama conjecture" that is part of the firewalls debate. Indeed, extremely massive black holes should have the least drama in the classical theory which describes black holes in the first place, so what feature of some quantum theory generates extremely high energy particles that we don't find anywhere between the Earth and Moon, or in the Jovian system, etc? "The firewall radiation can only be seen upon crossing an event horizon and there isn't one in those parts of our solar system" is not very satisfying, and it turns out that the arguably best-developed answer to that (by Afshordi/Dykaar/Abedi) is not significantly supported by gravitational wave data (so called repeating damped "echoes" cannot reliably be extracted from the noise) from LIGO, Virgo, and Kagra so far.
Though they might just be mathematical abstracts and not "real".
https://en.m.wikipedia.org/wiki/White_hole
https://physics.stackexchange.com/questions/740527/penrose-d...
A longer answer is somewhat model-dependent, and somewhat on how one chooses to split spacetime to distinguish spatial distances (for volume) and time (the volume is time-dependent). Unfortunately this means thatg for practicaly any given black hole there is no unique definition of its interior volume.
In general it is fairly safe to say that within generic black holes there is a small volume that tends towards infinite density, and that small volume is embedded in a much larger (even for a tiny-mass black hole) interior space, even fairly early in the (time-dependent) black hole's lifetime (e.g. within a few horizon-diameter light-crossing times after formation by matter collapse).
The most commonly known theoretical models of black holes are, absent perturbation, not time-dependent. This tends to highlight the non-uniqueness of interior volume. DiNunno & Matzner 2008 <https://arxiv.org/abs/0801.1734> is a fine pedagogical treatment. 'An occasional question to the teacher of relativity is: ".. then what is the volume of a black hole?" The answer is that, unlike the response about the surface, the volume depends on the way that the 3-dimensional "constant-time" space containing the black hole is defined.'
I have a memory of a fine and surprisingly accessible treatment by a mathematician about the interior volume of a Schwarzschild BH, but unfortunately I can't find the URL. There are plenty of other discussions about BH interior volumes scattered around the web and the academic literature, although a depressing number of the latter focus on anti-de Sitter (AdS) black holes. Black holes in our universe, like the one in the linked Chandra article or like Phoenix A, are decidedly not embedded in a collapsing spacetime with a lightlike boundary "screen" as would be the case if the exterior spacetime of these black holes were AdS rather than expanding Friedmann-Lemaître-Robertson-Walker with local overdensities (the galaxies around these black holes). Which is too bad, because if our universe were AdS, the interior volume of a black hole could have a nifty relationship with information complexity; in our universe, shrug.
Two more things for completeness. The exterior of a black hole, if not vacuum, can be relevant in determining the interior volume. Single black hole exact solutions (Schwarzschild, Kerr-Newman) have infinite vacuum outside the horizon, but one can introduce perturbations (lumps of matter or other mass-energy) that raise "bumps" on the horizon and strangenesses in the interior. For a large and relativistic perturbation like a second black hole, or a swarm of them, you run into the problem that in general single black hole solutions do not superpose well (and certainly not linearly). The interiors of "hard" black hole binaries may be very different from that of black hole binaries so soft (or wide, thinking only spatially) that they are barely in mutual orbit. And finally, black holes may evaporate completely, so the spacetime would then be finite, and thus it would be weird to cut the interior spacetime up into time-indexed spatial volumes where some of those volumes are infinite.
Consequently, calculating an average density comparable to that of a homogeneous ball of fluid (or even a differentiated planet like Earth) doesn't really say much about the black hole itself. And that I think is the weird thing related to your comment.
Finally, even for round-planet-sized objects and stars, the interior volumes "suffer" a mainly mass-dependent volume surplus compared to a Euclidean 3-ball. The interior Schwarzschild solution is a starting point; it provides a calculation for the volume of a self-gravitating sphere of a constant-density fluid or gas and this calculation reveals that that volume is greater than the corresponding empty spherical shell <https://en.wikipedia.org/wiki/Interior_Schwarzschild_metric#...>.
On another note, our senses generally work on a log scale (https://en.wikipedia.org/wiki/Weber–Fechner_law), so it’s not something unnatural.
Where confusion creeps back in is when sensory input is quantified. People don't perceive a 1000 lumen source as twice as bright as a 500 lumen source, but tend to think they should.
Is the universe so empty that it's not a problem? Are we just lucky that this object happens to be directly observable? What proportion of the sky is directly observable at 13.2 billion light years?
https://commons.wikimedia.org/wiki/File:Webb%27s_First_Deep_...
Even without a telescope, you can infer that space is mostly empty because the sky is dark at night:
Pretty much, yes.
There is plenty we have trouble viewing (e.g. objects that our own galactic plane obstructs), but the universe is Big. Which, luckily for us, means that even though plenty is hidden from our view, there's a lot that we can still observe.
https://www.nasa.gov/universe/webb-reveals-colors-of-earende...
You don't need 100% of the light to reach you to have a clear image of something. Even a small portion of the light is enough to get a clear image.
Also, I would suggest just because we can observe things doesn't mean we can observe them from every direction -- there are directions that are more empty and there are directions where we can't see well. For example, large part of our sky is blocked by our own galaxy arms and center and we can't see well much behind it.
And then there are things that we can observe only because we are extremely lucky (usually through gravitational lensing). When we say "we observed the oldest star" we don't mean there were no other stars at the time this one emitted the light.
But yes, in general, our universe is so empty that most of the light after it became translucent will never hit anything.
> You can clearly see images even through a mesh.
> You don't need 100% of the light to reach you to have a clear image of something. Even a small portion of the light is enough to get a clear image.
You can see something that's relatively large (in your field of vision) through a mesh. Something that's a tiny point seems like another matter.
Even if you can't see something directly, you could see emitted light indirectly, that reflects off something else. But that doesn't get you a direct image of it, like the ones the astronomy teams publish.
I thought the redshift value was typically given in the designation of these ultra-distant objects (e.g. GN-z11, GLASS-z12, GL-z13, JADES-GS-z13-0, at redshifts of ~11, ~12, ~13 respectively) but I guess that must not really be a "rule".
I think z ~ 10 is technically an ultra-high redshift galaxy. Table 2 in the "Treasury Survey" above predicts observations of tens of galaxies z > 12, when the universe at large is much more likely to be entirely electrically neutral (~ 10 is in the epoch of reionization, more or less). But please come back with "heroic" spectra from z ~ 15-30 (thinking of the linked article at the top with respect to direct-collapse black holes, Pop III, Lyman-Werner radiation, etc etc), or hey GW spectra from z > 10^10 - 10^30 (beyond scope of topic).
It is. Look up. Look down. The rock below and the sky above aren't homogeneous either (birds, clouds, trees; soil, roots, different size granules of sand and pebbles, clays, etc). But that's locally rather than at cosmologically-large scales.
Cosmic-scale isotropy and homgeneity give us a set of freefalling-in-deep-intergalaxy-cluster-space "Eulerian" observers who see, at the largest scales, a dust of galaxies surrounding them; we can build a set of coordinates that travel with these observers. These comoving coordinates are useful in cosmology, and are arguably "picked out" by the distribution of matter. From them we get the scale factor, a notion of cosmological time that applies throughout the entire universe. In principle any observer could determine a mapping between its preferred local system of coordinates and the comoving coordinates. In practice, we can determine the chemistry of distant objects via (red-shifted) spectral lines.
If the universe were anisotropic at the largest scales, but still homogeneous at the largest scales, we can consider a simple (dipole) case to start with: there is unignorably more matter and cosmic radiation in one half of the sky than in the other half, but each half has spiral galaxies galore. We would need a different system of cosmological coordinates, because observers to the left and right are effectively accelerated with respect to each other (and us, in the middle). The shape of the observable universe would differ; rather than the cosmic horizon(s) we have now that depend on the expansion history, we would have a set of Rindler-like wedges defining the boundaries of cause and effect that depend on both the expansion history and the relative anisotropy. Fascinatingly, the acceleration between the left and right gives an observer a very different evolution of particle numbers in each direction (if I remember late-noughties Einsteinian takes on Rastall's 1972 theory of gravitation, which I am not sure I do, the sparser half will fill with a surprisingly warm thermal bath, so the conservation of energy is broken much much harder in such a universe than in ours, which only has energy "disappear" as light and the like experience redshift with the expansion). We could of course complicate this into a multipole anisotropy, and get things that look even less like what we see. Because of that we "wash out" the local anisotropies (we ignore Andromeda and what we see of the Milky Way as "not cosmologically far enough") and find that the resulting isotropy and homogenity is a very good fit for the cosmic microwave background and ultra-deep-field astronomy. That will continue to be tested with gravitational wave astronomy.
Anisotropic and inhomogeneous cosmologies include those with supervoids and/or strangely-shaped masses (spirals and ellipticals here and there, but in other places or at supergalactic scales weirder structures dominate). One finds such cosmologies used in explorations of structure formation. These cosmologies can look much like ours, in terms of present-day observables. They're certainly more interesting for physicists when they are a very close match to our standard (homogeneous, isotropic) cosmology, but different enough to admit a different coupling between the expansion history and dark matter (the standard one dilutes dark matter in a predictable way at the largest scales, and similarly to the dilution of cold ordinary matter). Daniel Pomarède <https://en.wikipedia.org/wiki/Daniel_Pomar%C3%A8de> is a huge figure in that area of research, and the wiki bio is a good starting point if you have a deeper interest in your first question. Temperature winds up being very important, in part because of an acceleration between observers deep in a supervoid and observers in the non-void web-like or net-like structure, so we have to figure out why the cosmic microwave background doesn't seem to have large cold spots, and why the reticulated structure doesn't glow much warmer. This 2022 Starts With A Bang article by Ethan Siegal is relevant and may be of interest. <https://bigthink.com/starts-with-a-bang/cmb-cold-spot/>
Finally, your second and third questions are somewhere between "it's not necessary and doesn't really help" and "well if you adapt cosmology to favour a particular channel of early black hole formation you now need a mechanism to restore the small scale temperature fluctuations of the cosmic microwave background".
https://www.mathworks.com/matlabcentral/fileexchange/72254-s...
Blue is free falling into the hole. Yellow is observing and sees Blue’s clock come to a halt on the horizon. Beyond that much I can’t really explain but I found the link on this page:
https://physics.stackexchange.com/questions/689129/when-an-o...
Aka ~5 × 10^38 W. Why do astronomers use ergs?
Solar system: 30
UHZ1: 1