The jets are 23 million light years in length! That's 140 milky way galaxies laid out -- these are sizes I can't even begin to comprehend
Imagine the amount of energy required to create a jet that large! The scales are so big, it makes me wonder if there isn’t an upper limit to energy density. How much energy can be in one spot before you inadvertently create a Big Bang?
> it makes me wonder if there isn’t an upper limit to energy density
Yes, in a sense. The point at which the energy bends space-time into a black hole.
Actually, in theory there is one place denser but our models show it can never happen.
The moment right after the big bang. As energy can never be created nor destroyed, all the energy in the universe was practically in one point in space-time a femtosecond after the big bang.
This is a misunderstanding. All the energy in our « observable » universe was compressed in that small size. We do not have any estimates of the size of the actual universe now, nor at a time shortly after Big Bang. For all we know, the universe might be infinite, both now and back then.
My layman understanding is that we don't have the theories or math to try and understand this so it's just a black box that we pretend to understand
At that moment, why didn't the entire [mass of the] universe collapse into a black hole?
Perhaps gravity evolved.
That's a question that I always also asked myself, from my layman understanding space time expanded quicker than gravitational collapse
The whole concept of the Big Bang is a mind warp. The whole explosion must have happened in some… space-time thing to begin with. What was that immense point of matter and energy in? What was “around” it? We’ll never know.
Imagine a one meter long jet.
Congratulations, you've begun to comprehend it and now are at 1/(2.176 × 1023) of the total length.
10^23 is actually easy to comprehend, because it’s close to the amount of h2o molecules in a syringe. Just that many meters.
If the plasma jet is wildly larger than our entire galaxy, I wonder if some sort of exotic life could evolve inside the jet. Some sort of life that would be totally rare in the universe.
Sometimes I wonder if our whole universe is some kind of transient aberration, if you zoom out far enough
For all we know, we live inside some large scale invisible jet and our entire understand of physics is really the exception rather than the rule
if you zoom out far enough, there's no other option (imo)
We are little critters living in space squirts
You are getting a single plastid. No more, no less.
Not my field, but could the Big Bang have been a massive black hole that "spat" out jets of plasma that formed into new stars and galaxies? I call this the black hole big burp theory.
This is very close to an idea known as "Black hole cosmology" -- basically the idea being that the visible universe is inside a black hole, leading to a sort of "nested multiverse".
A related theory, rather than being inside a black hole, is that the other side of a black hole is a "white hole". As matter collapses into a black hole, it is emitted from the white hole, creating another universe.
Here's an article from 2010 that expands on the idea, though this is definitely not the first time (or last time) it was discussed, it just happens to be an easily searchable article.
I'm sure it's not practical, but I always thought it would be interesting if instead of living "inside" a black hole, the visible universe was simply being consumed by a black hole so large it just encompassed everything outside the visible part. So no nesting, the universe just eventually gets consumed entirely by one black hole.
Wait a minute, I missed the discussion
Wow, thanks for the resources! I actually never heard of a living universe 'inside' a black hole.
Interesting read. Her proposal for a “bounce” cosmology sounds like it has a neat explanation for why things appear smooth, but as far as why/how the universe should bounce at all (especially given current consensus that the current universe will NOT bounce) are only briefly gestured at (“promising recent work”, to paraphrase).
Has that work developed and found traction among physicists in the 7 years since the article?
Interesting! It would be nice to solve dark matter & excise inflation in one stroke (or a few strokes). My lay understanding of PBHs—as-dark-matter is that it has been whittled down to a pretty tight range of their masses, though, bounded by “they would’ve already evaporated” and “we’d already have detected them”
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> I wonder if some sort of exotic life could evolve
Some might say humans are exotic life that evolved.
And to think that we witness this from the comfort of our pocket sized terminals makes me happy, but also sad that maybe mankind will not reach spacefaring… great filter and all… dunno
Is it possible for these jets to hit other galaxies/stars/planets?
Just think... in the presence of a constant magnetic field, this could be the most powerful particle collider in the visible universe
I have a question about black holes, HN.
Let’s say you have a black hole. You fire a laser beam straight into it. Just by symmetry, shouldn’t it blueshift on the way in, gain some preposterous amount of energy — enough that it can escape?
> shouldn’t it blueshift on the way in, gain some preposterous amount of energy — enough that it can escape
You're devilishly close to the Penrose process by which "energy can be extracted from a rotating black hole" [1]. (You can also make them explode [2].)
There _is_ no amount of energy it could gain to escape though. It goes no faster, gets no closer to escape. It just splats into the black hole and we'll never see it again no matter how much energy it started with or gained.
Light travels in a straight line - black holes don't "pull" light in, they change what a straight line looks like in the space around it.
The event horizon is the distance where all straight lines lead to the black hole.
Very exciting until they figure out the jet is just a Starlink satellite passing in front of the telescope.
John C. Wright in the Count to the Escaton sequence. But it's just part of the background of awesome while the real people story plays out in the foreground (as it should)
What happens to the plasma that the black hole spits out? Do they have any ideas?
I studied these objects for my first research paper in grad school. (You can see a few images of some of the objects I found in Figure 3 of my paper [1]) In essence the jet blows a hot bubble into the gas that comprises the intracluster medium of the galaxy cluster. Over time synchrotron radiation causes the bubble to cool down and eventually (maybe on the order of a few 100 million to a billion years if I recall right) the bubble comes into thermal equilibrium with the surrounding gas.
I thought that only hawking radiation could escape a black hole. Now a paper describing a vast jet of emitted plasma??
The article doesn't quite clarify this point. It mentions the jets shooting from below and above the black holes, but does this mean they're emerging from their interior or being created by the accretion of superheated material that forms in orbit around black holes?
The article simple states this, which seems wrong given the immense gravity of black holes:
>When supermassive black holes become active—in other words, when their immense forces of gravity tug on and heat up surrounding material—they are thought to either emit energy in the form of radiation or jets.
So the holes themselves emit energy jets or their accretion disks do? Sloppy damn phrasing and reporting, and all too common for science subjects.
Its not coming out of the black hole itself, its more like the black hole has an accretion disk around it of material that is being sucked in. The dynamics of the huge forces and energies involved can cause jets to form, throwing high energy particles away from the black hole. The jets still represent a tiny fraction of the matter, most of which is still heading into the hole.
And crazy strong and twisted magnetic fields that will heat things up/create large forces on charged particles.
If you track down the original source, there's a video of the lead author of the Nature paper explaining how it works:
Hawking radiation is one process, but for spinning black holes, especially ones with accretion disks and magnetic fields around them, there are two more theoretical predictions: the Blandford–Znajek process and the Penrose process.
The jets are 23 million light years in length! That's 140 milky way galaxies laid out -- these are sizes I can't even begin to comprehend
Imagine the amount of energy required to create a jet that large! The scales are so big, it makes me wonder if there isn’t an upper limit to energy density. How much energy can be in one spot before you inadvertently create a Big Bang?
> it makes me wonder if there isn’t an upper limit to energy density
Yes, in a sense. The point at which the energy bends space-time into a black hole.
Actually, in theory there is one place denser but our models show it can never happen.
The moment right after the big bang. As energy can never be created nor destroyed, all the energy in the universe was practically in one point in space-time a femtosecond after the big bang.
This is a misunderstanding. All the energy in our « observable » universe was compressed in that small size. We do not have any estimates of the size of the actual universe now, nor at a time shortly after Big Bang. For all we know, the universe might be infinite, both now and back then.
My layman understanding is that we don't have the theories or math to try and understand this so it's just a black box that we pretend to understand
At that moment, why didn't the entire [mass of the] universe collapse into a black hole?
Perhaps gravity evolved.
That's a question that I always also asked myself, from my layman understanding space time expanded quicker than gravitational collapse
The whole concept of the Big Bang is a mind warp. The whole explosion must have happened in some… space-time thing to begin with. What was that immense point of matter and energy in? What was “around” it? We’ll never know.
It wasn't an explosion. Space itself expanded, so there wasn't anything to expand into. https://en.wikipedia.org/wiki/Expansion_of_the_universe
One word, AGI
Pretty crazy!
Imagine a one meter long jet. Congratulations, you've begun to comprehend it and now are at 1/(2.176 × 1023) of the total length.
10^23 is actually easy to comprehend, because it’s close to the amount of h2o molecules in a syringe. Just that many meters.
If the plasma jet is wildly larger than our entire galaxy, I wonder if some sort of exotic life could evolve inside the jet. Some sort of life that would be totally rare in the universe.
Sometimes I wonder if our whole universe is some kind of transient aberration, if you zoom out far enough
For all we know, we live inside some large scale invisible jet and our entire understand of physics is really the exception rather than the rule
if you zoom out far enough, there's no other option (imo)
We are little critters living in space squirts
You are getting a single plastid. No more, no less.
Not my field, but could the Big Bang have been a massive black hole that "spat" out jets of plasma that formed into new stars and galaxies? I call this the black hole big burp theory.
This is very close to an idea known as "Black hole cosmology" -- basically the idea being that the visible universe is inside a black hole, leading to a sort of "nested multiverse".
https://en.wikipedia.org/wiki/Black-hole_cosmology
A related theory, rather than being inside a black hole, is that the other side of a black hole is a "white hole". As matter collapses into a black hole, it is emitted from the white hole, creating another universe.
Here's an article from 2010 that expands on the idea, though this is definitely not the first time (or last time) it was discussed, it just happens to be an easily searchable article.
https://www.space.com/8293-universe-born-black-hole-theory.h...
I'm sure it's not practical, but I always thought it would be interesting if instead of living "inside" a black hole, the visible universe was simply being consumed by a black hole so large it just encompassed everything outside the visible part. So no nesting, the universe just eventually gets consumed entirely by one black hole.
Wait a minute, I missed the discussion
Wow, thanks for the resources! I actually never heard of a living universe 'inside' a black hole.
This seems incompatible with inflation
Isn't universe inflation already on shaky ground though? https://www.scientificamerican.com/article/cosmic-inflation-...
Interesting read. Her proposal for a “bounce” cosmology sounds like it has a neat explanation for why things appear smooth, but as far as why/how the universe should bounce at all (especially given current consensus that the current universe will NOT bounce) are only briefly gestured at (“promising recent work”, to paraphrase).
Has that work developed and found traction among physicists in the 7 years since the article?
This was on the front page a couple weeks back iirc: https://www.livescience.com/physics-mathematics/dark-matter/...
Interesting! It would be nice to solve dark matter & excise inflation in one stroke (or a few strokes). My lay understanding of PBHs—as-dark-matter is that it has been whittled down to a pretty tight range of their masses, though, bounded by “they would’ve already evaporated” and “we’d already have detected them”
> I wonder if some sort of exotic life could evolve
Some might say humans are exotic life that evolved.
And to think that we witness this from the comfort of our pocket sized terminals makes me happy, but also sad that maybe mankind will not reach spacefaring… great filter and all… dunno
The referenced paper: https://www.nature.com/articles/s41586-024-07879-y
Is it possible for these jets to hit other galaxies/stars/planets?
Just think... in the presence of a constant magnetic field, this could be the most powerful particle collider in the visible universe
I have a question about black holes, HN.
Let’s say you have a black hole. You fire a laser beam straight into it. Just by symmetry, shouldn’t it blueshift on the way in, gain some preposterous amount of energy — enough that it can escape?
> shouldn’t it blueshift on the way in, gain some preposterous amount of energy — enough that it can escape
You're devilishly close to the Penrose process by which "energy can be extracted from a rotating black hole" [1]. (You can also make them explode [2].)
[1] https://en.wikipedia.org/wiki/Penrose_process
[2] https://en.wikipedia.org/wiki/Black_hole_bomb
It will gain energy.
There _is_ no amount of energy it could gain to escape though. It goes no faster, gets no closer to escape. It just splats into the black hole and we'll never see it again no matter how much energy it started with or gained.
Light travels in a straight line - black holes don't "pull" light in, they change what a straight line looks like in the space around it.
The event horizon is the distance where all straight lines lead to the black hole.
Very exciting until they figure out the jet is just a Starlink satellite passing in front of the telescope.
I’ve seen stellar engines [1] show up in fiction.
Has anyone done a galactic engine?
[1] https://en.m.wikipedia.org/wiki/Stellar_engine
John C. Wright in the Count to the Escaton sequence. But it's just part of the background of awesome while the real people story plays out in the foreground (as it should)
What happens to the plasma that the black hole spits out? Do they have any ideas?
I studied these objects for my first research paper in grad school. (You can see a few images of some of the objects I found in Figure 3 of my paper [1]) In essence the jet blows a hot bubble into the gas that comprises the intracluster medium of the galaxy cluster. Over time synchrotron radiation causes the bubble to cool down and eventually (maybe on the order of a few 100 million to a billion years if I recall right) the bubble comes into thermal equilibrium with the surrounding gas.
[1]: https://arxiv.org/pdf/1204.3896
slows, cools, condenses into us sometimes
I think it just blasts off into the universe
Panspermia?
One hell of a thruster.
[flagged]
I thought that only hawking radiation could escape a black hole. Now a paper describing a vast jet of emitted plasma??
The article doesn't quite clarify this point. It mentions the jets shooting from below and above the black holes, but does this mean they're emerging from their interior or being created by the accretion of superheated material that forms in orbit around black holes?
The article simple states this, which seems wrong given the immense gravity of black holes:
>When supermassive black holes become active—in other words, when their immense forces of gravity tug on and heat up surrounding material—they are thought to either emit energy in the form of radiation or jets.
So the holes themselves emit energy jets or their accretion disks do? Sloppy damn phrasing and reporting, and all too common for science subjects.
Its not coming out of the black hole itself, its more like the black hole has an accretion disk around it of material that is being sucked in. The dynamics of the huge forces and energies involved can cause jets to form, throwing high energy particles away from the black hole. The jets still represent a tiny fraction of the matter, most of which is still heading into the hole.
And crazy strong and twisted magnetic fields that will heat things up/create large forces on charged particles.
If you track down the original source, there's a video of the lead author of the Nature paper explaining how it works:
https://www.caltech.edu/about/news/gargantuan-black-hole-jet...
Hawking radiation is one process, but for spinning black holes, especially ones with accretion disks and magnetic fields around them, there are two more theoretical predictions: the Blandford–Znajek process and the Penrose process.
https://en.m.wikipedia.org/wiki/Astrophysical_jet#Rotation_a...
Truly, what kind of pedants would downvote an honest question about this poorly described detail?
I've seen people say "you're not supposed to mention" downvotes if they happen to you, but when they're plainly stupid?