Earlier quoted context omitted.
Partition them by velocity
Velocity relative to what?
Relative to CMB.
JWST spots giant black holes all over the early universe
131–140 of 186 posts
Re: JWST spots giant black holes all over the early universe
#132Earlier quoted context omitted.
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.
> 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."
If you're sufficiently cynical, you can describe almost all astronomy results that way. Lots of alternate explanations for the observations have been proposed, and fail to match the full evidence.
Just how much evidence are you going to demand of phenomena hundreds of lightyears away before you say, "yeah, that's probably what it is"? Anyway, do be sure to read the whole list of observations linked above by csours, as there are quite a few.
Re: JWST spots giant black holes all over the early universe
#133So 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. w…
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 o…
... 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.)
Re: JWST spots giant black holes all over the early universe
#134I'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.
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.
Re: JWST spots giant black holes all over the early universe
#135Earlier quoted context omitted.
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.
That doesn't follow. A galaxy is not like a star system that orbits a single massive object in a single plane. Objects orbit the center of mass of the galaxy, which is made of of an enormous mass of stars and clouds of dust and gas. For example, the central molecular zone (CMZ) is an asymmetrical roughly spherical region, about 1600-1900 light years in diameter, that contains about 60 million solar masses of gas and…
An excellent reply, far better than my idle musings warranted, however a point was missed. At some point in solar system formation the mass of the not quite yet a sun was only 6% of the mass of the entire system. At some very early point I assume the distribution of mass in the proto solar dust cloud would be the same as the distribution of mass in the galaxy.
I hesitate to reinforce my idea because really, it is ill informed musings on how solar system formation is coalescing gas and dust clouds and would galaxy sized objects eventually coalesce into the same proportion of objects. ill-informed because it turns out we can look into the past and see what newer galaxies look like.
Anyway, thank you again for a great post.
Re: JWST spots giant black holes all over the early universe
#136Earlier quoted context omitted.
I guess we might be better off if Pol Pot had killed more smart people than he did. Maybe Trump will win and finish off the rest of us and you can be happy. We dill die fighting though, good luck
> We dill die fighting though I agree for the rest but will we? The planet is burning and we don't do shit.
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Re: JWST spots giant black holes all over the early universe
#137The 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…
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.)
Re: JWST spots giant black holes all over the early universe
#138Earlier quoted context omitted.
What if you have 3.14Pi?
Then you're so close to 10 that you can just use 10. I actually did that on a physics exam once. Somehow I had a value with pi squared. I just replaced it with 10. I don't remember if I got that question right or wrong - I'm hard pressed to think of a situation where pi squared actually legitimately shows up.
Surface area of a Torus?
Re: JWST spots giant black holes all over the early universe
#139Maybe 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…
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).
Re: JWST spots giant black holes all over the early universe
#140The 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…
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?
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.