Gravity is half spin hyperdimensional vector torsion. I have decided to accept “half spin torsion” as “vortex” and see gravity as the torsion interference along a G <timespace> dimensionality.
There are other dimensionality!
The dimensions are like origami, not parallel universes, however the relationships are as though such (all origami pieces then hyperdimensionality relate.)
If we call the underlying “universal potential” and whatever we think our universe as, is a plane for hyperdimensional coordinates, much of this will begin to make sense.
Gravity (and space time) is a “universal field” that “falls”
Around the distributed mass (vector torsions of mass particles) and mass particles are universal potential (same stuff as measured energy in a photon) is half spin vector locked discrete amounts.
Sub-atomic particles may then be discrete spin lock configurations and not distinct in any other way.
This would make the Higgs particle a lie, and the Higgs field this deformation of gravitational surface area.
Just what I’ve come up with. Existential reality (universal potential distributing) is holographic and gravity is half spin vector torsion on a plane of universal existence.
Like matter verses anti-matter? If so I think this has actually been considered by physicists hence we tested to ensure that anti-matter responds to gravity in the same way as matter.
If anit-matter had shown anti-gravity effects then gravity may have been just some imbalance of forces in the universe, but it doesn't appear to be that way.
As a non expert who's just curious about science but also tries to talk like a normal person, from what I can tell holography really seems like it's now the leading candidate to be the next big conceptual revolution in physics.
There's not necessarily any breakthrough right around the corner and we shouldn't rush to coronation preemptively, but there's a lot of physics "voting with their feet" for holography as the article says, and I think it's officially time to start getting hyped. It could have sanity-restoring answers to questions of quantum weirdness, albeit at the rather expensive cost of giving up even more on our day to day intuitions about space and time in favor of an apparently informational substrate.
String theory had a generation of great science communicators writing its books and singing its praises, but holography doesn't yet have equivalent public champions, and I hope that's something that changes sooner than later.
No string theory (10d) or m theory (11d) map to lower dimensions (eg 4d) via (generalisation of) Kaluza Klein compactification. Vector boson (eg maxwell or Yang mills) are internal degree la of freedom-> 6/7d graviton becomes a photon/ gluon.
There’s holography in string theory: AdS/CFT but this rather maps 4d super Yang mills (on the boundary of AdS5) in an AdS5xS5 background: which is one holography correspondence we know works.
Holography is much more common, but we only really understand it on hyperbolic spaces.
Also since it has a theory at strong coupling on one side we cannot really do calculation on that side and verify it.
Many concepts can be framed as projections onto lower dimensions. It’s the specific ways in which things are projected that makes things string theory. IOW don’t mistake the concept of a map for the territory that one type of map describes.
I don't think the distinction between holography and string theory is as clean as you're making it. The vague idea of holography predates string theory, but most of the working examples we have of holography come from string theory. That's what AdS/CFT is: It's an explicitly holographic description of superstring theory in an anti-Desitter space. It's frankly bizarre that the author of this article doesn't mention that fact. I suspect we are seeing a popular science rebranding of string theory without the word strings.
I didn't intend to assert a clean distinction, you're exactly right about its connection to string theory. What I mean is that String Theory Writ Large enjoyed a lot of popular esteem in the 00s and 2010s in public communication as being our potential new framework for what lies beneath the quantum world, but string theory is huge in and of itself.
It's more a difference of emphasis (holography in particular) than something that's outside the scope of string theory.
String theory had a generation of great science communicators writing its books and singing its praises...
I would argue that has done more harm than good. Strong media personalities shouting "the next big breakthrough is here!" followed by 25 years of zero practical results have not done good things for public perception of field of physics. A layperson could be mistaken for assuming the field is literally regressing.
Holography implies that you can do that — reconstruct every fold, vessel, and neuron in three dimensions — without actually looking inside. Simply photographing the surface of the brain somehow suffices.
Gah I am not a fan of pop-sci simplifications like this for the sake of a soundbite. The author goes onto explain how no, a picture is not enough, you need to actually measure the distortion of spacetime at the surface. Somebody is going to walk away thinking this stuff is possible, that maybe psychics really can detect something wrong with them.
I know what you mean and I think you're right, but I take it as the cost of doing business when trying to turn frontier physics into layperson analogies. You're not going to use an analogy to successfully complete a calculation of black hole entropy, you're going to use it to convey the high level intuition that "stuff on inside = stuff on boundary".
Because if we litigate the imperfections of analogies all day long, then you're going to react to videos titled "black holes described at five levels of difficulty" by saying the first four levels were all wrong, which may in a sense be technically true but not in the spirit of the exercise.
It's okay as long as they call it out, but the author doesn't and instead states it like a fact. They could have easily caveated it with "but a magical camera that can see magnetic and gravitational fields" or something. The analogy is fine, but it's not presented as one, so it's not clear how far the analogy actually goes. So the takeaway is "wow technically it's possible!"
Consider a video game sun passing behind a video game tree. The sun pixels touch the tree pixels directly, yet the tree does not burst into flames. This is because the sun pixels are independent of the tree pixels.
With apologies to Babbage, I am not able rightly to apprehend the kind of confusion of ideas that could provoke such an explanation.
lol yikes. Some of the other illustrations quoted seemed OK esp if you already have a layman's understanding of the major concepts... but this just seems.... bad.
Just as acceleration through space causes [the same effect as] gravity, could regular gravity be the movement through TIME?
Could gravity be a facet of time as electricity is to magnetism and vice versa? and the reason we cannot "isolate" gravity is because it's interwoven with time?
But then it would be weird that photos who don't experience time are affected by gravity..
When I read "But holography really starts to bite only after..." my LLM-dar goes off. Everything I read up to that point was comprehensible, but man, I have developed a shudder reaction to any language suggesting AI was involved ibn its creation.
I find AI written stuff to be hard to read. Part of my career is being a writer and I take great pride in my outout. AI written materials is a slog because you can see how it's pumping out words to hit various metrics rather than what's needed for the task.
LOL, same. Usually I watch with a great, much deserved attention, but sometimes I need to work on something so I replay videos, and his voice, with such a fantastic cadence and soothing registry, talking about things I deeply enjoy and appreciate, makes work easier and better.
My nitpick is with something the author said in passing about Hawking.
Yes, around 1970 Hawking and the scientific community at large still used to believe nothing could escape a black hole, and between 1971 and 1973 Hawking along with Penrose and others expanded their evolving understanding and consequences of of Albert Einstein's breakthrough work.
But then Hawking argued back the opposite case, which in simple terms means that some things can, indeed, escape an event horizon. In fact, name dropping Hawking just to mention his views as they stood before his 1973 work, and his 1974 model of Hawking radiation seems dangerously incomplete journalistic reporting.
In 1974 Hawking formulated what we now know as Hawking Radiation, which is the *exact opposite* of what was previously believed about the impossibility of anything coming back from a black hole. Whilst still not conclusively proven as a physical fact, this did win him the Special Fundamental Physics Prize in 2013. specifically for his discovery of Hawking radiation from black holes and his deep contributions to quantum gravity and quantum aspects of the early universe.
I find myself not agreeing with a lot of nitpicks, but this is a good one! The article says "Contrary to what Stephen Hawking argued, black holes are not inescapable prisons." But information escaping black holes is named after him! He definitely, in the full scope of his career, was perfectly agreeable to the idea of information escaping black holes.
Hawking found that energy/mass can escape but the information remains destroyed. You can't run a black hole backwards in time and reconstruct the matter that created it and hawking radiation bears no resemblance to anything that was ever beyond the horizon.
Not sure I follow your comment exactly, perhaps I am misunderstanding it but Hawking radiation doesn't involve anything escaping a black hole.
The radiation never originates from within the event horizon. Furthermore the radiation itself does not encode any information about what fell into the black hole apart from the electric charge, angular momentum, and mass (all of which must remain conserved).
The only caveat that I'd ask about is the death of a black hole after it evaporates away too much mass. If that explosion does occur, is that matter/energy that was from inside the singularity itself?
AFAICT nobody has a consistent theory proven by observations. Some theories offer an explosion in which the singularity vanishes, but this has trouble with information / entropy. Some say a microscopic remnant stops radiating because the original assumptions of Hawking radiation mechanism do not apply at near-Planck scale. Some say that as the curvature grows with the diameter shrinking, the black hole pops off from "our" spacetime and forms a parallel universe, without an explosion.
The current age of the Universe is way small compared to the time needed for evaporation, so observing anything like that happening (or not) is hardly possible.
Indeed All Hawking radiation takes from a black hole is some mass. It's a bit like radiation resulting from annihilation of matter and antimatter: it does not "escape", it "gets born" in the process.
We can play with words all day, but in the sense of a particle entering into the event horizon of a black hole and then at some point in the future exiting from inside of the event horizon, that simply never happens and Hawking radiation does not propose that.
I don't know the slightest about this but... That list looks like it is supposed to be limited but that sounds like infinitely more information than zero?
> Not sure I follow your comment exactly, perhaps I am misunderstanding it but Hawking radiation doesn't involve anything escaping a black hole.
> The radiation never originates from within the event horizon. Furthermore the radiation itself does not encode any information about what fell into the black hole apart from the electric charge, angular momentum, and mass (all of which must remain conserved).
I don't know the slightest about this but... That list looks like it is supposed to be limited but that sounds like infinitely more information than zero?
I don't know about electric charge, but can't you observe mass and angular momentum of a black hole from outside? I think the "no information" thing means the Hawking radiation won't let you tell you if the black hole was made from a dead star or just a really big pile of meat or what's going on inside of it.
IIRC, all Hawking radiation does is provide a mechanism for a black hole to eventually decay.
It's been ages since I read it and I am 99% sure I'm remember horribly wrong, but I was thinking it's something like this? Also - your "the only information" is precisely what we can measure of quantum states, so information is still preserved. That's more a limit of what we know?
I think that with Hawking radiation you have quantum entanglement of two pairs. You have a matter-antimatter pair production near the horizon. When the antimatter falls into the blackhole without being destroyed via mutual annihilation, the matter particle at the boundary now "radiates" away. HOWEVER.
The matter inside boundary which the anti-matter DOES interact with is destroyed, and the information of that interaction is is "passed" to the outside via the the anti-matter's entanglement with its co-created pair.
Something like that, isn't it? Please any physicists clarify :)
I think that with Hawking radiation you have quantum entanglement of two pairs. You have a matter-antimatter pair production near the horizon. When the antimatter falls into the blackhole without being destroyed via mutual annihilation, the matter particle at the boundary now "radiates" away. HOWEVER.
That's not how Hawking radiation actually works. It's just a "lies-to-the-children" explanation. Antiparticles have positive mass, so the black hole would be _growing_ as a result. This mechanism also violates the equivalency principle, as you shouldn't be able to detect the event horizon with only local observations.
Reality is more interesting. In flat space, the ground state of quantum fields is actually non-zero. But black holes "bias" the fields in such a way that their ground state becomes _negative_ from the viewpoint of a remote observer.
This in turn permits it to create new particles from just nothing. This in turn adds _negative_ energy to that space, resulting in the black hole decreasing in mass.
But crucially, the event horizon itself is NOT involved. Particle creation can happen anywhere in the vicinity of the black hole, not just on the event horizon.
Please correct my understanding as I am not a scientist, but why do you assert that Hawking radiation "escapes" or "comes out of" a black hole? Nothing crosses the event horizon. Isn't it more correct to say that Hawking radiation is produced by the extreme warping of the spacetime very near the event horizon, and the black hole shrinks to conserve the energy? Black holes can also shrink as gravitational waves are produced, but we don't say that the waves "escape" the black hole.
My understanding is that Hawking radiation is where:
1. a particle/anti-particle pair is created at the event horizon;
2. the particle is on the outside edge of the event horizon, so "escapes" the black hole;
3. the anti-particle is on the inside edge of the horizon, so decreases the size of the black hole due to particle/anti-particle annihilation (with a corresponding particle on the inside of the black hole).
This is often used as an explanation in pop-sci materials, but it isn't particularly accurate, IIRC.
For example, Hawking radiation is always photons, with the wavelength corresponding to the size of the black hole. That isn't explained purely by virtual particles.
Also, for that explanation to work, it would always have to be an anti-matter particle that is selected to cross the event horizon, and I don't see how that would be the case.
Minor quibbles: Hawking radiation has a blackbody spectrum, so we get a variety of wavelengths, with a peak determined by the size of the hole. The outgoing particles should eventually include any kind of particle that can be created in the Standard Model, not just photons and gravitons.
Strangely, it is _not_ the instrinsic curvature of spacetime that produces Hawking radiation. There's a variation on Hawking radiation -- called Unruh radiation -- experienced by accelerated observers in flat spacetime. Any two observers will agree on the value of a field (e.g. the electric field) at a point, but an accelerated observer will experience empty spacetime as a _thermal bath of particles_, with a temperature proportional to the acceleration. Relatively accelerated observers don't agree on what the vacuum is.
You’re missing a big issue here… Hawking Radiation doesn’t escape from within the event horizon, and there’s no physical process preventing that. It’s radiation from the surface of the black hole, not the interior.
This doesn't make sense. Which consciousness is absolute? Yours or mine? Because I can't see your consciousness; I can only infer its existence. You can't see my consciousness; you can only infer its existence.
All possible subsets of a Universal Set can be considered as Observers. So a Power Set is collection of observers. Power Set of Power Set is another such collection. So on and so forth. Powersets all the way up.
With gravity, mass plays the role of charge. It bends space-time around it, and it is always positive. There is no negative mass, so you can always infer the one real arrangement of stuff inside from the warping of space-time at the surface of your box.
This is a simplification to the point of just being wrong. Gauss’s law works for gravity; if you put a shell around Earth you have no way of knowing whether it’s a planet or an Earth-mass black hole inside. Assuming spherical symmetry of density, anyway.
This is a simplification to the point of just being wrong.
Is it? If you project a "3D" singularity onto a surface, it's still a point. If you project a roughly spherical object, it's roughly circular.
Gauss' law in this case would apply to the total force of gravity exerted by the mass within the shell, not its distribution across the surface of the shell.
I assumed the analogy meant that just by measuring the gravitational field outside the shell, you could figure out the mass distribution inside. And you can't, not in the general case.
I think the box explanation is misleading. There isn't literally a box whose surface you measure. The idea is that the state of a higher-dimensional gravitational system can, in some cases, be completely described by a theory in one fewer dimension.
Is the "in some cases" constraint really necessary? I thought Bousso's whole point in his talk linked elsewhere in this thread is that you can describe a 3D system in terms of 2D information.
Could you keep going, fully describing systems of higher order in less and less dimensions?
This article seems to repeatedly blur the distinction between 'having space' to encode all the states inside a volume on it's surface and an actual theory of correspondence of states.
"Having space" is just a consequence of black holes. If you have more information in a volume than can be encoded on its surface in theory, you have enough mass inside the volume to make it a black hole and the event horizon then has enough space to encode the information even if the original surface did not.
The correspondence between information, thermodynamics, and mass that causes black holes to 'make it possible' to holographically encode all the information inside is what makes this theory so tempting. What if everything is information, and black holes aren't an expression of 'too much mass', but rather just a result of 'too much information to store'. This theory, if it existed, would demonstrate a key result of both relativity and quantum theory based on a very simple premise, and suggests it might then be possible to base both General Relativity and Quantum Theory on top of a simpler theory.
That’s a violation of logic and geometry. It asks us to erase the categorical difference between square meters and cubic meters.
No, that's sheer nonsense.
There is no negative mass, so you can always infer the one real arrangement of stuff inside from the warping of space-time at the surface of your box.
Positive mass does not make this argument work. Two bodies in GR can have different distributions of mass but identical exterior geometry. A counterexample is two spherically symmetric, uncharged bodies with the same total gravitational mass but different radial density profiles. By Birkhoff’s theorem, their exterior vacuum geometries are identical.
Mathematician, not physicist, but it seems reasonable to me that you could encode a sufficiently constrained 3D space on a 2D boundary. And if you have such an encoding, it also doesn't seem insane that some things might be more easily modeled on the 2D boundary than the 3D space.
If you can convert back and forth between a 2D representation and a 3D representation, and different phenomena are more easily modeled in each, does it matter which is "real"? Unless of course you can come up with a specific prediction and experiment to test it.
The YouTube video was uploaded 18 years ago, and looks like it was filmed on a VHS camcorder. I guess it could have been 480p as the original would have been 480i, but it wouldn’t look all that much better.
I haven't watched it so far, but I'd expect some diagrams on a chalk-, or whiteboard, maybe some 'overhead' projection. These will all be almost unrecognizable at that resolution, on current screens. Would have to try to upscale with AI. Which I won't.
My favorite quote and a point where something really clicked was when he said "If you tried smaller you would instead be making a Planck-size black hole".
Is the physical nonlocality of the relationship between the bulk and boundary somehow related to the noncontinuity of any bijection between manifolds of different dimension?
In recent years, they’ve started to get more creative. Susskind and other teams have made progress [link] on holographic de Sitter models [link] that differ radically from AdS/CFT. Instead of squashing a volume into an area, these universes seem to cram all the dimensions into a lone quantum point.
If unitarity and the no-hiding theorem are true and the Big Bag emerged from a point, doesn’t it follow that all the information about the universe was once contained in a dimensionless point?
At sufficiently high energies, interactions that appear distinct at low energies may be described by larger underlying symmetries. Symmetries reduce the amount of independent information needed to describe a system. So the early universe can admit a remarkably compact description.
Regarding unitarity, an initial state does not need to contain a record of a history preceding it; unitarity only requires that subsequent evolution preserve the information encoded in the quantum state. Later states may contain enormously complicated correlations that simply did not yet exist in the initial state.
And there is no general principle saying that a large amount of quantum information requires a large classical spatial volume. A Hilbert space can support an enormous number of possible states even when its geometric description is extremely compact.
More importantly, the universe didn't emerge from a dimensionless point. The (t=0) singularity is the limit where classical general relativity breaks down and stops being a useful description, so the ordinary picture of information as some number of independent "bits" packed into a 3D space is no longer obviously applicable. A coherent theory of quantum gravity would probably be needed to really break further ground.
You can “compress all of the three-dimensional world into two dimensions.”
That sounds a little like the sophons in the novel Three Body Problem. IIRC, aliens took a photon, unfolded it to a flat surface to etch circuitry on, then folded it back up and fired the photon at earth where it unfolded again and did the bidding of the aliens.
you can decipher the entire contents of the box just by repeatedly measuring points on the surface
So if the box is both inside and outside of a black hole, is that a path for information to leave a black hole?
I immediately thought of the painter analogy (from the books which are astonishingly good) of "painting" 3D objects into 2D objects from the stories, and wondered if the author was exploring the reverse of this "perfect painting" that is still "functional". I'm definitely a lay person, I know enough physics to use a lever to lift heavy things.
More like space opera is my point. Science fiction projects out into the future to extrapolate from current science, it doesn't invent a parallel reality that is contradictory with already understood science.
When all gravity runs out, and all forces fizzle into the vaccuum, entropy returns to a single maximally ordered state indistinguishable from any other. Identical conditions for a Big Bang.
Consider time itself: one beginning, and many endings. Why many endings? And who even asks the question in the first place? Many intelligent observers, with many endings, but the same beginnings. Perhaps the black holes are a hint to our own ending?
We're born and blink into existence. And then we die and fade into the void, carrying our varied stories with us.
Logically, it doesn't make sense, and we can't possibly know the answer. But what if all those ends wrapped around to the same beginning?
- Time is strictly perceptual. The Universe as a whole (including changes in the fourth dimension) has always existed and will always exist. There is no 'end of time'.
- When your portion of the universe runs out (death) you just rerun it again. Because linear time is an illusion that helps us make sense of it (and not fear the future) and in reality we're skipping all over the place constantly. Forever. So hope your life isn't terrible. You're going to be reliving it infinitely. Enjoy.
To me (a total physics layperson with just an interest in it) space and time HAVE to be emergent and not fundamental because of the real phenomena of spooky action at a distance and dual slit craziness. All spacetime surely has to be connected is what it’s telling us.
Or hear me out here… we as a species have developed measuring methodology that is precise enough at human scale but not actually correct and breaks down at larger scales.
As far as I understand it,the relative time as we know it, is just something that emerges from the fact that all particle interactions travel with constant light speed.
So if anything moves, the interactions don't change their speed, they stay constant, but the delta to the movement changes, and thus time dilates.
Would be interesting to know if there is some absolute/fundamental global time that has nothing to do with the time we perceive.
Pause for a moment to reflect on how outrageous this assertion is. You can’t see into the box at all. Nevertheless, holography says that you can learn exactly what’s happening everywhere in the box without any access to the interior. Observing the surface alone is enough. In this sense, the amount of stuff that fills a box is the same as the amount of paint that covers it. That’s a violation of logic and geometry.
The breathless tone of this article obscures rather than illuminates its subject. It sounds as if the author describes a box with some particles bouncing around inside, and every time a particle bounces off the wall of the box the outside glows briefly indicating the location and intensity of the collision. The author is amazed that by repeatedly measuring this, you can draw inferences about what's going on in the box.
I can't see what's 'outrageous' about this. You need a lower surface which registers information about activity inside a higher-dimensional volume, some way to accurately read that information, and the time/patience to repeat the measurement many times. Isn't this how radar works, or feeling your way around a pitch-dark room using only the 2-dimensional surface of your hands (or shins)? We know from computer science that you can mathematically encode any structure of arbitrary dimension into a binary tree. One might as well ask how it's possible that our complex 3 dimensional world can be contained in the flat surface of a mirror, film strip, or camera sensor.
It’s not just drawing inferences, though; it’s saying you can determine exactly what’s happening in the box. But the pigeonhole principle would suggest there’s far more possible states in the 3-dimension volume than can be unique expressed on the 2-dimensional surface. That’s the part that defies common sense.
Does it? Isn't this basically the same as how cellular companies can figure out exactly where someone is calling from as long as their phone is pinging 3+ towers? Just connect the towers into a box and you have the same result.
The metaphor as written is maybe bad, but the holographic idea really is outrageous and mindboggling. Because according to it the inside might as well be completely empty.
Gravity is half spin hyperdimensional vector torsion. I have decided to accept “half spin torsion” as “vortex” and see gravity as the torsion interference along a G <timespace> dimensionality.
There are other dimensionality!
The dimensions are like origami, not parallel universes, however the relationships are as though such (all origami pieces then hyperdimensionality relate.)
If we call the underlying “universal potential” and whatever we think our universe as, is a plane for hyperdimensional coordinates, much of this will begin to make sense.
Gravity (and space time) is a “universal field” that “falls” Around the distributed mass (vector torsions of mass particles) and mass particles are universal potential (same stuff as measured energy in a photon) is half spin vector locked discrete amounts.
Sub-atomic particles may then be discrete spin lock configurations and not distinct in any other way.
This would make the Higgs particle a lie, and the Higgs field this deformation of gravitational surface area.
Just what I’ve come up with. Existential reality (universal potential distributing) is holographic and gravity is half spin vector torsion on a plane of universal existence.
Physics threads on HN can be so entertaining.
Any HN thread where real thought is required devolves into insanity quickly.
What if you half spin the other direction?
Why would it matter?
A torsion to the right, a torsion to the left mate in circular momentum.
Sounds like complementary spins.
Like matter verses anti-matter? If so I think this has actually been considered by physicists hence we tested to ensure that anti-matter responds to gravity in the same way as matter.
If anit-matter had shown anti-gravity effects then gravity may have been just some imbalance of forces in the universe, but it doesn't appear to be that way.
Using a spin lock is wasteful and not the best move in times of rising energy prices. Use a mutex to put the waiting thread to sleep.
Spin lock traps potential, requiring more energy than available to release.
That trapped potential in time and space is mass rather than radial propagation.
This is an interesting theory, but I think it has less explanatory power than the Sugon framework for gravity.
This is not a theory.
You are half spin torsioning my subatomic particles right now
As a non expert who's just curious about science but also tries to talk like a normal person, from what I can tell holography really seems like it's now the leading candidate to be the next big conceptual revolution in physics.
There's not necessarily any breakthrough right around the corner and we shouldn't rush to coronation preemptively, but there's a lot of physics "voting with their feet" for holography as the article says, and I think it's officially time to start getting hyped. It could have sanity-restoring answers to questions of quantum weirdness, albeit at the rather expensive cost of giving up even more on our day to day intuitions about space and time in favor of an apparently informational substrate.
String theory had a generation of great science communicators writing its books and singing its praises, but holography doesn't yet have equivalent public champions, and I hope that's something that changes sooner than later.
isn't holographic universe a similar concept to string theory in that they both propose higher dimensions projecting into lower dimensions
string theory, 11 dimensions, is bonkers though, it's what happens when people are too smart for their own good imho lol
Eh, 11 dimensions is just what the math predicts based on the theory’s postulate and observations of the universe.
Holographic gravity is no less fanciful if there’s no practical experiment to prove it.
No string theory (10d) or m theory (11d) map to lower dimensions (eg 4d) via (generalisation of) Kaluza Klein compactification. Vector boson (eg maxwell or Yang mills) are internal degree la of freedom-> 6/7d graviton becomes a photon/ gluon.
There’s holography in string theory: AdS/CFT but this rather maps 4d super Yang mills (on the boundary of AdS5) in an AdS5xS5 background: which is one holography correspondence we know works.
Holography is much more common, but we only really understand it on hyperbolic spaces.
Also since it has a theory at strong coupling on one side we cannot really do calculation on that side and verify it.
You can use it tho to make calculations.
Many concepts can be framed as projections onto lower dimensions. It’s the specific ways in which things are projected that makes things string theory. IOW don’t mistake the concept of a map for the territory that one type of map describes.
I don't think the distinction between holography and string theory is as clean as you're making it. The vague idea of holography predates string theory, but most of the working examples we have of holography come from string theory. That's what AdS/CFT is: It's an explicitly holographic description of superstring theory in an anti-Desitter space. It's frankly bizarre that the author of this article doesn't mention that fact. I suspect we are seeing a popular science rebranding of string theory without the word strings.
I didn't intend to assert a clean distinction, you're exactly right about its connection to string theory. What I mean is that String Theory Writ Large enjoyed a lot of popular esteem in the 00s and 2010s in public communication as being our potential new framework for what lies beneath the quantum world, but string theory is huge in and of itself.
It's more a difference of emphasis (holography in particular) than something that's outside the scope of string theory.
I would argue that has done more harm than good. Strong media personalities shouting "the next big breakthrough is here!" followed by 25 years of zero practical results have not done good things for public perception of field of physics. A layperson could be mistaken for assuming the field is literally regressing.
Could be forgiven?
Yes, thanks!
Damnit, I rewrote that sentence twice and still got it wrong.
Gah I am not a fan of pop-sci simplifications like this for the sake of a soundbite. The author goes onto explain how no, a picture is not enough, you need to actually measure the distortion of spacetime at the surface. Somebody is going to walk away thinking this stuff is possible, that maybe psychics really can detect something wrong with them.
I know what you mean and I think you're right, but I take it as the cost of doing business when trying to turn frontier physics into layperson analogies. You're not going to use an analogy to successfully complete a calculation of black hole entropy, you're going to use it to convey the high level intuition that "stuff on inside = stuff on boundary".
Because if we litigate the imperfections of analogies all day long, then you're going to react to videos titled "black holes described at five levels of difficulty" by saying the first four levels were all wrong, which may in a sense be technically true but not in the spirit of the exercise.
It's okay as long as they call it out, but the author doesn't and instead states it like a fact. They could have easily caveated it with "but a magical camera that can see magnetic and gravitational fields" or something. The analogy is fine, but it's not presented as one, so it's not clear how far the analogy actually goes. So the takeaway is "wow technically it's possible!"
It is Quanta, the home of sensationalist oversimplifcations. What did you expect, solid science?
Yes, the rest of the article is pretty good.
This was the low point for me:
With apologies to Babbage, I am not able rightly to apprehend the kind of confusion of ideas that could provoke such an explanation.
lol yikes. Some of the other illustrations quoted seemed OK esp if you already have a layman's understanding of the major concepts... but this just seems.... bad.
<Layperson>
Just as acceleration through space causes [the same effect as] gravity, could regular gravity be the movement through TIME?
Could gravity be a facet of time as electricity is to magnetism and vice versa? and the reason we cannot "isolate" gravity is because it's interwoven with time?
But then it would be weird that photos who don't experience time are affected by gravity..
Or maybe space, time and gravity are a trinity?
(no I'm not high, but maybe I should be)
is this why i increase in mass and volume every year?
Do you also attract more things?
Where did you get a photo that isn't effected by gravity?
fuck lol photon
When I read "But holography really starts to bite only after..." my LLM-dar goes off. Everything I read up to that point was comprehensible, but man, I have developed a shudder reaction to any language suggesting AI was involved ibn its creation.
I find AI written stuff to be hard to read. Part of my career is being a writer and I take great pride in my outout. AI written materials is a slog because you can see how it's pumping out words to hit various metrics rather than what's needed for the task.
PBS Space Time, could watch it all day, sometimes listen in the background all day
* https://www.youtube.com/watch?v=DoCYY9sa2kU
* https://www.youtube.com/watch?v=klpDHn8viX8
* https://www.youtube.com/watch?v=qYSKEbd956M
* https://www.youtube.com/watch?v=YNEBhwimJWs
LOL, same. Usually I watch with a great, much deserved attention, but sometimes I need to work on something so I replay videos, and his voice, with such a fantastic cadence and soothing registry, talking about things I deeply enjoy and appreciate, makes work easier and better.
My nitpick is with something the author said in passing about Hawking. Yes, around 1970 Hawking and the scientific community at large still used to believe nothing could escape a black hole, and between 1971 and 1973 Hawking along with Penrose and others expanded their evolving understanding and consequences of of Albert Einstein's breakthrough work.
But then Hawking argued back the opposite case, which in simple terms means that some things can, indeed, escape an event horizon. In fact, name dropping Hawking just to mention his views as they stood before his 1973 work, and his 1974 model of Hawking radiation seems dangerously incomplete journalistic reporting.
In 1974 Hawking formulated what we now know as Hawking Radiation, which is the *exact opposite* of what was previously believed about the impossibility of anything coming back from a black hole. Whilst still not conclusively proven as a physical fact, this did win him the Special Fundamental Physics Prize in 2013. specifically for his discovery of Hawking radiation from black holes and his deep contributions to quantum gravity and quantum aspects of the early universe.
I find myself not agreeing with a lot of nitpicks, but this is a good one! The article says "Contrary to what Stephen Hawking argued, black holes are not inescapable prisons." But information escaping black holes is named after him! He definitely, in the full scope of his career, was perfectly agreeable to the idea of information escaping black holes.
Those claims are backwards.
Hawking found that energy/mass can escape but the information remains destroyed. You can't run a black hole backwards in time and reconstruct the matter that created it and hawking radiation bears no resemblance to anything that was ever beyond the horizon.
Not sure I follow your comment exactly, perhaps I am misunderstanding it but Hawking radiation doesn't involve anything escaping a black hole.
The radiation never originates from within the event horizon. Furthermore the radiation itself does not encode any information about what fell into the black hole apart from the electric charge, angular momentum, and mass (all of which must remain conserved).
The only caveat that I'd ask about is the death of a black hole after it evaporates away too much mass. If that explosion does occur, is that matter/energy that was from inside the singularity itself?
AFAICT nobody has a consistent theory proven by observations. Some theories offer an explosion in which the singularity vanishes, but this has trouble with information / entropy. Some say a microscopic remnant stops radiating because the original assumptions of Hawking radiation mechanism do not apply at near-Planck scale. Some say that as the curvature grows with the diameter shrinking, the black hole pops off from "our" spacetime and forms a parallel universe, without an explosion.
The current age of the Universe is way small compared to the time needed for evaporation, so observing anything like that happening (or not) is hardly possible.
Indeed All Hawking radiation takes from a black hole is some mass. It's a bit like radiation resulting from annihilation of matter and antimatter: it does not "escape", it "gets born" in the process.
I'm not sure that is a meaningful distinction. All a black hole _is_, is mass. If you take away the mass, you are taking away the black hole.
It's also information / entropy, hence the https://en.wikipedia.org/wiki/Black_hole_information_paradox
And electric charge, which is conserved!
The entire blackhole will eventually evaporate, so yes it is literally escaping from the black hole.
We can play with words all day, but in the sense of a particle entering into the event horizon of a black hole and then at some point in the future exiting from inside of the event horizon, that simply never happens and Hawking radiation does not propose that.
I don't know the slightest about this but... That list looks like it is supposed to be limited but that sounds like infinitely more information than zero?
I don't know about electric charge, but can't you observe mass and angular momentum of a black hole from outside? I think the "no information" thing means the Hawking radiation won't let you tell you if the black hole was made from a dead star or just a really big pile of meat or what's going on inside of it.
IIRC, all Hawking radiation does is provide a mechanism for a black hole to eventually decay.
It's been ages since I read it and I am 99% sure I'm remember horribly wrong, but I was thinking it's something like this? Also - your "the only information" is precisely what we can measure of quantum states, so information is still preserved. That's more a limit of what we know?
I think that with Hawking radiation you have quantum entanglement of two pairs. You have a matter-antimatter pair production near the horizon. When the antimatter falls into the blackhole without being destroyed via mutual annihilation, the matter particle at the boundary now "radiates" away. HOWEVER.
The matter inside boundary which the anti-matter DOES interact with is destroyed, and the information of that interaction is is "passed" to the outside via the the anti-matter's entanglement with its co-created pair.
Something like that, isn't it? Please any physicists clarify :)
That's not how Hawking radiation actually works. It's just a "lies-to-the-children" explanation. Antiparticles have positive mass, so the black hole would be _growing_ as a result. This mechanism also violates the equivalency principle, as you shouldn't be able to detect the event horizon with only local observations.
Reality is more interesting. In flat space, the ground state of quantum fields is actually non-zero. But black holes "bias" the fields in such a way that their ground state becomes _negative_ from the viewpoint of a remote observer.
This in turn permits it to create new particles from just nothing. This in turn adds _negative_ energy to that space, resulting in the black hole decreasing in mass.
But crucially, the event horizon itself is NOT involved. Particle creation can happen anywhere in the vicinity of the black hole, not just on the event horizon.
Please correct my understanding as I am not a scientist, but why do you assert that Hawking radiation "escapes" or "comes out of" a black hole? Nothing crosses the event horizon. Isn't it more correct to say that Hawking radiation is produced by the extreme warping of the spacetime very near the event horizon, and the black hole shrinks to conserve the energy? Black holes can also shrink as gravitational waves are produced, but we don't say that the waves "escape" the black hole.
My understanding is that Hawking radiation is where:
1. a particle/anti-particle pair is created at the event horizon;
2. the particle is on the outside edge of the event horizon, so "escapes" the black hole;
3. the anti-particle is on the inside edge of the horizon, so decreases the size of the black hole due to particle/anti-particle annihilation (with a corresponding particle on the inside of the black hole).
This is often used as an explanation in pop-sci materials, but it isn't particularly accurate, IIRC.
For example, Hawking radiation is always photons, with the wavelength corresponding to the size of the black hole. That isn't explained purely by virtual particles.
Also, for that explanation to work, it would always have to be an anti-matter particle that is selected to cross the event horizon, and I don't see how that would be the case.
Minor quibbles: Hawking radiation has a blackbody spectrum, so we get a variety of wavelengths, with a peak determined by the size of the hole. The outgoing particles should eventually include any kind of particle that can be created in the Standard Model, not just photons and gravitons.
Strangely, it is _not_ the instrinsic curvature of spacetime that produces Hawking radiation. There's a variation on Hawking radiation -- called Unruh radiation -- experienced by accelerated observers in flat spacetime. Any two observers will agree on the value of a field (e.g. the electric field) at a point, but an accelerated observer will experience empty spacetime as a _thermal bath of particles_, with a temperature proportional to the acceleration. Relatively accelerated observers don't agree on what the vacuum is.
You’re missing a big issue here… Hawking Radiation doesn’t escape from within the event horizon, and there’s no physical process preventing that. It’s radiation from the surface of the black hole, not the interior.
Would this imply that time is the third dimension?
Wouldn't time be one of the two resulting dimensions - the other being space?
Aside: Quanta magazine always has excellent design & visuals.
space is an illusion...The only thing that is absolute is consciousness, on top of which all illusions stand.
This doesn't make sense. Which consciousness is absolute? Yours or mine? Because I can't see your consciousness; I can only infer its existence. You can't see my consciousness; you can only infer its existence.
Ours. Or every ones..We can easily accept that we inhabit the same spacetime. Why is it hard to imagine the same for consciousness?
Because deceit and lies exist.
Consciousness is the greatest illusion of them all.
Get a load of this. You can have only consciousness and still have a sensation of a full universe.
Tell me again how Consciousness is an illusion..
All possible subsets of a Universal Set can be considered as Observers. So a Power Set is collection of observers. Power Set of Power Set is another such collection. So on and so forth. Powersets all the way up.
This is a simplification to the point of just being wrong. Gauss’s law works for gravity; if you put a shell around Earth you have no way of knowing whether it’s a planet or an Earth-mass black hole inside. Assuming spherical symmetry of density, anyway.
Is it? If you project a "3D" singularity onto a surface, it's still a point. If you project a roughly spherical object, it's roughly circular.
Gauss' law in this case would apply to the total force of gravity exerted by the mass within the shell, not its distribution across the surface of the shell.
I assumed the analogy meant that just by measuring the gravitational field outside the shell, you could figure out the mass distribution inside. And you can't, not in the general case.
I think the box explanation is misleading. There isn't literally a box whose surface you measure. The idea is that the state of a higher-dimensional gravitational system can, in some cases, be completely described by a theory in one fewer dimension.
For black holes it is quite literal tho.
So like describing the properties of a sphere by using a circle.
Is the "in some cases" constraint really necessary? I thought Bousso's whole point in his talk linked elsewhere in this thread is that you can describe a 3D system in terms of 2D information.
Could you keep going, fully describing systems of higher order in less and less dimensions?
This article seems to repeatedly blur the distinction between 'having space' to encode all the states inside a volume on it's surface and an actual theory of correspondence of states.
"Having space" is just a consequence of black holes. If you have more information in a volume than can be encoded on its surface in theory, you have enough mass inside the volume to make it a black hole and the event horizon then has enough space to encode the information even if the original surface did not.
The correspondence between information, thermodynamics, and mass that causes black holes to 'make it possible' to holographically encode all the information inside is what makes this theory so tempting. What if everything is information, and black holes aren't an expression of 'too much mass', but rather just a result of 'too much information to store'. This theory, if it existed, would demonstrate a key result of both relativity and quantum theory based on a very simple premise, and suggests it might then be possible to base both General Relativity and Quantum Theory on top of a simpler theory.
No, that's sheer nonsense.
Positive mass does not make this argument work. Two bodies in GR can have different distributions of mass but identical exterior geometry. A counterexample is two spherically symmetric, uncharged bodies with the same total gravitational mass but different radial density profiles. By Birkhoff’s theorem, their exterior vacuum geometries are identical.
Isn't this the same as Newton's shell theorem?
Yep! Although it's different due to lack of superposition, I think it happens to work out for spherical shells.
Mathematician, not physicist, but it seems reasonable to me that you could encode a sufficiently constrained 3D space on a 2D boundary. And if you have such an encoding, it also doesn't seem insane that some things might be more easily modeled on the 2D boundary than the 3D space.
If you can convert back and forth between a 2D representation and a 3D representation, and different phenomena are more easily modeled in each, does it matter which is "real"? Unless of course you can come up with a specific prediction and experiment to test it.
Yeah, there's a great talk about the physics of the holographic information encoded on the surface by Raphael Bousso (if you have an hour):
https://www.youtube.com/watch?v=GHgi6E1ECgo
HIGHLY recommend it for lay folks interested in this stuff. Which reminds me, I should yt-dl this so it's not lost, and I have a copy...
In 240p only? :-(
The YouTube video was uploaded 18 years ago, and looks like it was filmed on a VHS camcorder. I guess it could have been 480p as the original would have been 480i, but it wouldn’t look all that much better.
VHS has an effective resolution of ~240p anyway.
How much more knowledge are you hoping to extract from a 4K version?
There’s some physics-y Shannon entropy data or black hole joke in there somewhere I just am not mart enough to find it.
I haven't watched it so far, but I'd expect some diagrams on a chalk-, or whiteboard, maybe some 'overhead' projection. These will all be almost unrecognizable at that resolution, on current screens. Would have to try to upscale with AI. Which I won't.
I watched the whole thing, I didn't notice anything substantial lost.
what app do you use for yt-dl?
https://github.com/yt-dlp/yt-dlp seems to be a more currently maintained fork of the original https://github.com/ytdl-org/youtube-dl/
https://github.com/yt-dlp/yt-dlp is generally where the most up-to-date workarounds for Google's attempts to block downloads are.
This is a great video, thanks for sharing.
My favorite quote and a point where something really clicked was when he said "If you tried smaller you would instead be making a Planck-size black hole".
Is the physical nonlocality of the relationship between the bulk and boundary somehow related to the noncontinuity of any bijection between manifolds of different dimension?
If 3D space can be packed into a 2D hologram, then, can that 2D data be packed into a 1D hologram and so on?
The article touches on that:
In recent years, they’ve started to get more creative. Susskind and other teams have made progress [link] on holographic de Sitter models [link] that differ radically from AdS/CFT. Instead of squashing a volume into an area, these universes seem to cram all the dimensions into a lone quantum point.
If you read the article, one of the analogy points to this. Compressing everything to a point.
But I had the same question few months back. Asking Claude is fruitful in this case.
If unitarity and the no-hiding theorem are true and the Big Bag emerged from a point, doesn’t it follow that all the information about the universe was once contained in a dimensionless point?
At sufficiently high energies, interactions that appear distinct at low energies may be described by larger underlying symmetries. Symmetries reduce the amount of independent information needed to describe a system. So the early universe can admit a remarkably compact description.
Regarding unitarity, an initial state does not need to contain a record of a history preceding it; unitarity only requires that subsequent evolution preserve the information encoded in the quantum state. Later states may contain enormously complicated correlations that simply did not yet exist in the initial state.
And there is no general principle saying that a large amount of quantum information requires a large classical spatial volume. A Hilbert space can support an enormous number of possible states even when its geometric description is extremely compact.
More importantly, the universe didn't emerge from a dimensionless point. The (t=0) singularity is the limit where classical general relativity breaks down and stops being a useful description, so the ordinary picture of information as some number of independent "bits" packed into a 3D space is no longer obviously applicable. A coherent theory of quantum gravity would probably be needed to really break further ground.
1D = unus Deus
That sounds a little like the sophons in the novel Three Body Problem. IIRC, aliens took a photon, unfolded it to a flat surface to etch circuitry on, then folded it back up and fired the photon at earth where it unfolded again and did the bidding of the aliens.
So if the box is both inside and outside of a black hole, is that a path for information to leave a black hole?
I immediately thought of the painter analogy (from the books which are astonishingly good) of "painting" 3D objects into 2D objects from the stories, and wondered if the author was exploring the reverse of this "perfect painting" that is still "functional". I'm definitely a lay person, I know enough physics to use a lever to lift heavy things.
Different topic, but the sophon idea in TBP revealed the author's complete ignorance of basic particle physics.
…it’s Science Fiction
More like space opera is my point. Science fiction projects out into the future to extrapolate from current science, it doesn't invent a parallel reality that is contradictory with already understood science.
It's touted as "hard science fiction" but it's riddled with this kind of stuff.
I think by definition if part of you is in a black hole, the bits inside it can't affect (or communicate information to) your bits that are outside.
This is cool, but I've noticed that an idea of a "holographic universe" makes the news roughly once a decade.
Maybe fifth time's the charm. ;-)
Only time tells!
Fascinating article... reminds me once again why I went into EE/CS instead of physics, I just wasn't smart enough :-(
When all gravity runs out, and all forces fizzle into the vaccuum, entropy returns to a single maximally ordered state indistinguishable from any other. Identical conditions for a Big Bang.
Consider time itself: one beginning, and many endings. Why many endings? And who even asks the question in the first place? Many intelligent observers, with many endings, but the same beginnings. Perhaps the black holes are a hint to our own ending?
We're born and blink into existence. And then we die and fade into the void, carrying our varied stories with us.
Logically, it doesn't make sense, and we can't possibly know the answer. But what if all those ends wrapped around to the same beginning?
Would you look at the world differently?
what does this mean?
A theory is: blackholes give off Hawking radiation at the end of their lives.
I'm of course, oversimplifying things for a fun thought experiment. Everyone wonders about reincarnation, death, and the 'end of time'.
Just a thought experiment that's not grounded in anything. We all believe what we want and act accordingly.
- Time is strictly perceptual. The Universe as a whole (including changes in the fourth dimension) has always existed and will always exist. There is no 'end of time'.
- When your portion of the universe runs out (death) you just rerun it again. Because linear time is an illusion that helps us make sense of it (and not fear the future) and in reality we're skipping all over the place constantly. Forever. So hope your life isn't terrible. You're going to be reliving it infinitely. Enjoy.
Compassion and good times run out too quickly. I hope we all do alright. It's naive but who cares.
To me (a total physics layperson with just an interest in it) space and time HAVE to be emergent and not fundamental because of the real phenomena of spooky action at a distance and dual slit craziness. All spacetime surely has to be connected is what it’s telling us.
Or hear me out here… we as a species have developed measuring methodology that is precise enough at human scale but not actually correct and breaks down at larger scales.
As far as I understand it,the relative time as we know it, is just something that emerges from the fact that all particle interactions travel with constant light speed.
So if anything moves, the interactions don't change their speed, they stay constant, but the delta to the movement changes, and thus time dilates.
Would be interesting to know if there is some absolute/fundamental global time that has nothing to do with the time we perceive.
"Spooky action at a distance" only happens in some interpretations of quantum mechanics, and not, for example, in MWI.
Pause for a moment to reflect on how outrageous this assertion is. You can’t see into the box at all. Nevertheless, holography says that you can learn exactly what’s happening everywhere in the box without any access to the interior. Observing the surface alone is enough. In this sense, the amount of stuff that fills a box is the same as the amount of paint that covers it. That’s a violation of logic and geometry.
The breathless tone of this article obscures rather than illuminates its subject. It sounds as if the author describes a box with some particles bouncing around inside, and every time a particle bounces off the wall of the box the outside glows briefly indicating the location and intensity of the collision. The author is amazed that by repeatedly measuring this, you can draw inferences about what's going on in the box.
I can't see what's 'outrageous' about this. You need a lower surface which registers information about activity inside a higher-dimensional volume, some way to accurately read that information, and the time/patience to repeat the measurement many times. Isn't this how radar works, or feeling your way around a pitch-dark room using only the 2-dimensional surface of your hands (or shins)? We know from computer science that you can mathematically encode any structure of arbitrary dimension into a binary tree. One might as well ask how it's possible that our complex 3 dimensional world can be contained in the flat surface of a mirror, film strip, or camera sensor.
It’s not just drawing inferences, though; it’s saying you can determine exactly what’s happening in the box. But the pigeonhole principle would suggest there’s far more possible states in the 3-dimension volume than can be unique expressed on the 2-dimensional surface. That’s the part that defies common sense.
Is it any weirder than the fact that there is a bijection between the unit interval and the unit square?
A 3d volume can contain a number of states equal to it's 2d dimensional surface.
All the extra states you would assume the 3d volume can contain are actually a single state called Black Hole.
There is a limit to how much you can fill a 3d volume before it's a Black Hole basically.
That's the clearest description of how this dimension collapse via gravity thing works that I've ever heard.
I really think we live on the 3D event horizon of a 4D black hole, folks.
Does it? Isn't this basically the same as how cellular companies can figure out exactly where someone is calling from as long as their phone is pinging 3+ towers? Just connect the towers into a box and you have the same result.
Build an object out of legos and then reconstruct the shape of what you built by only looking at it from the sides and above.
I'm not sure if I agree, but you certainly articulated it far more clearly than the original writer.
The metaphor as written is maybe bad, but the holographic idea really is outrageous and mindboggling. Because according to it the inside might as well be completely empty.
I don't think the author has relevant scientific background and it's frustrating this wasn't written by one of the Quanta journalists who does.
Going with the video game analogy, would the characters made out of pixels ever have a way to perceive the console and TV that created them?