14 ms·

Black hole paradoxes reveal a fundamental link between energy and order

163 points by nnx 6y ago

peter_d_sherman 6y ago
>"Plumbing black holes for knowledge of quantum gravity originated with Stephen Hawking. In 1974, the British physicist calculated that quantum jitter at the surfaces of black holes cause them to evaporate, slowly shrinking as they radiate heat." If heat is related to a black hole shrinking, and a black hole shrinking is related to information, then perhaps heat is related to information, and vice-versa. [...] >"In that case, the universe of the far future will be littered with tiny, indestructible black hole remnants — the remains of any black holes that carry even a touch of charge..." You mean like an atom? Perhaps atoms (and other particles, in fact, all other particles) are really just black holes! Perhaps curved space is a better way to look at it... perhaps all black holes (and all particles) are really just curved space... in fact, perhaps all waves are curved space too... Which would mean that everything in the universe, all of its particles, all of its waves, all of its contents, including the universe itself... is basically curved space... in one form or another... [...] >"In a paper published in March in Physical Review Letters, [Garrett] Goon and Riccardo Penco broadened the lessons of the earlier work by proving a simple, universal formula relating energy and entropy. The newfound formula applies to a system such as a gas as well as a black hole." If gases (particulate matter spread thinly in a thinner medium, i.e., space) can be related to black holes, then black holes can be related to the particles in the gases, which lends additional credence to the idea that all atoms are black holes, although, this being said, it's not a hard proof... [...] >"When they combine Einstein’s gravity equations and the equations of electromagnetism, they calculate that a black hole’s charge, Q, can never surpass its mass, M, when both are converted into the same fundamental units. Together, the black hole’s mass and charge determine its size — the radius of the event horizon. Meanwhile, the black hole’s charge also creates a second, “inner” horizon, hidden behind the event horizon." Super weird idea here... if we thought about a black hole of whatever size holographically, as information, then what would be true if the inner, hidden part of the black hole actually contained a miniature replica, a miniature mirror-image -- of ALL of the information inside this universe, a universe-inside-of-a-universe? That's highly speculative of course, but I think it's an idea worth exploring... [...] ">When a black hole hits this point, a simple option for further decay would be to split into two smaller black holes." You mean like + and - on a battery terminal? Let me go for "full crackpot theorist" <g>... What if charge, as we know it, in electricity, is implemented by various clusters of small black holes, regions of curved space, that we have (up until this point in time) been calling by such names as "charge", "electron", "electricity", "potential", "potential difference", etc. When, what you've got might be multiple black holes, split into pairs, where one is a complex conjugate, a mirror image of the other, and they basically want to unify and annihilate, producing various wavelengths (heat/information) in the process? All physics should be solvable once the correct identities are established between apparently dissimilar phenomena...
- cjfd 6y ago
  Sure, one can speculate that. There is quite a lot of devil in the details, though. One thing that is a bit unclear when it is 'all curved space' is how one would ever get spin 1/2 particles, i.e., non-integer spin particles. E.g., in string theory one has to invent a 'fermionic string' to get them otherwise one only gets integer spin particles. Also it is not clear how 'multiple black holes' are going to be a stable configuration together.
  - peter_d_sherman 6y ago
    I'm not saying I'm right... I'm just saying "it may be worth exploring..." Nothing more, nothing less! <g>
    - ngold 6y ago
      I had fun.
    - qubex 6y ago
      There’s plenty of ‘exploring’ going on. The famous “ER = EPR hypotheis” suggests that entangled particles are opposite ends of a wormhole.
  - wrnr 6y ago
    I always thought that the non integer spin was more of an historic artefact, because they measured the photon first. Not my area of expertise, but does the half spin have any meaning?
    - wnoise 6y ago
      Well, it acts quite a bit like an angular momentum of that amount, including obeying conservation laws jointly with regular ("orbital") angular momentum. I don't know of a good way of explaining the half-integral nature without diving into representation theory. The short story is: 1. Conservation laws and continuous symmetries are the same thing. The standard explanation of this is when we move or turn the system, the rules it obeys are the same. Or alternately change our view of the system by picking different origin and axes for our coördinate systems, the form of the rules (how to evolve, how to measure, how to predict) remains the same. This is Noether's theorem. 2. But symmetries don't mean our description of a system is unchanged. It means that our descriptions must change in a compatible way with our new point of view. 3. Cashing this out in math, symmetries are groups acting on states. Having the states transform compatibly means these actions must be "linear representations of groups". 4. A spin-one object has the wave function (normally considered the fundamental state) act like a vector under rotations, and because symmetry under rotation is angular momentum, this must be too. 5. When we do this quantum mechanically, all of our predictions come from the density matrix, where the wave function enters twice (as an outer product). A spin-1/2 object has the density matrix transform like a vector, and the wave-function itself transforms "like a spinor", which is to say, itself.
mormegil 6y ago
> In that case, the universe of the far future will be littered with tiny, indestructible black hole remnants — the remains of any black holes that carry even a touch of charge I don't get that. Wouldn't the charge be neutralized by consuming particles with an opposite charge (which are attracted gravitationally and electrically)? Or even by merging two extremal black holes with opposite charge?
- hellofunk 6y ago
  I think if you read the article, they talk about this far future hypothesis.
at_a_remove 6y ago
Here's the one that has bugged me since I first learned of Hawking radiation as an undergrad: if it is true (it's still unobserved but let's go with it), that means that merely passing through the event horizon allows for violation of the conservation of baryon number. I generally regard most of the "Star Trek physics" ideas like FTL with the hairy eyeball, but this one really gets me. Being able to violate the conservation of baryon number (and lepton number, for that matter) would point to -- in some scenarios -- mass-energy conversion being a lot more available than the laborious processes of fission, fusion, and particle/antiparticle mutual annihilation.
- simonh 6y ago
  Surely the conservation of baryon numbers is just a rule for reactions. I don’t see how crossing the event horizon changes anything. Remember from the POV of the baryon, it never crosses the event horizon. It’s not really ‘destroyed’, it just becomes unobservable to the external universe.
  - qubex 6y ago
    True, but from the point of view of an observer at infinity, the baryon falls and comes to a halt, while the event horizon of the black hole expands and encompasses it (or would, if you could measure the diameter of the black hole with sufficient precision). This is just the essence of the information paradox, expressed in terms of baryon and lepton numbers. Either the Hawking radiation that comes out is ‘correlated’ with the matter that fell in (meaning that black holes have hair) and information is preserved, or they’re not, and information is destroyed. That’s literally the crux of the matter.
    - simonh 6y ago
      That’s a good point, I wasn’t thinking about it in terms of the information paradox, but then the recently proposed solutions look like they have a good chance of panning out. https://en.wikipedia.org/wiki/Black_hole_information_paradox#Recent_developments https://en.wikipedia.org/wiki/Black_hole_information_paradox... But anyway I still don’t think this is really an issue regardless. The same could be said of the cosmic event horizon. Vast swathes of the universe are unobservable and causally disconnected from us due to the expansion of the universe separating us at faster than the speed of light. Again, no Baryons are being destroyed in this process, they’re just becoming unobservable _to_us_. https://en.wikipedia.org/wiki/Event_horizon#Cosmic_event_horizon https://en.wikipedia.org/wiki/Event_horizon#Cosmic_event_hor...
andrewflnr 6y ago
I remember reading somewhere that charged black holes would quickly lose their charge by radiating charged particles rather than, I guess, purely neutral photons. I've been taking that for granted for a while now, but don't remember exactly where I read it. Does anyone know where that hypothesis comes from and how it relates to the work in article?
- qubex 6y ago
  I think the prevailing notion is another, namely that an electrically charged black hole would quickly neutralise by preferentially attracting particles of opposite charge.
  - AnimalMuppet 6y ago
    In particular, if a charged black hole creates Hawking pairs, the oppositely-charged particle is more likely to be captured than the same-charge particle.
  - wnoise 6y ago
    Once Hawking radiation is produced at all, those are the same process.
pierrebai 6y ago
As a true amateur,I don't understand the basic premise of this extremal black hole mystery. In my simple view, if a charged black whole is extremal and cannot shrink then... the solution simply is that it must grow again. It absorbs particles of the opposite charge until it becomes neutral enough to shrink again and the process repeat until it completely evaporate. That seems both a simple and straightforward theory. (Then my other misunderstanding is how a black whole would become so charged when the universe is seemingly so neutral. The law of big number ensures that a black hole would be mostly neutral and the extremal case would only happen for very small ones on the brink of evaporation.)
zzv 6y ago
What a ridiculously well-written article!

163 points by nnx 6y ago

>"Plumbing black holes for knowledge of quantum gravity originated with Stephen Hawking. In 1974, the British physicist calculated that quantum jitter at the surfaces of black holes cause them to evaporate, slowly shrinking as they radiate heat." If heat is related to a black hole shrinking, and a black hole shrinking is related to information, then perhaps heat is related to information, and vice-versa. [...] >"In that case, the universe of the far future will be littered with tiny, indestructible black hole remnants — the remains of any black holes that carry even a touch of charge..." You mean like an atom? Perhaps atoms (and other particles, in fact, all other particles) are really just black holes! Perhaps curved space is a better way to look at it... perhaps all black holes (and all particles) are really just curved space... in fact, perhaps all waves are curved space too... Which would mean that everything in the universe, all of its particles, all of its waves, all of its contents, including the universe itself... is basically curved space... in one form or another... [...] >"In a paper published in March in Physical Review Letters, [Garrett] Goon and Riccardo Penco broadened the lessons of the earlier work by proving a simple, universal formula relating energy and entropy. The newfound formula applies to a system such as a gas as well as a black hole." If gases (particulate matter spread thinly in a thinner medium, i.e., space) can be related to black holes, then black holes can be related to the particles in the gases, which lends additional credence to the idea that all atoms are black holes, although, this being said, it's not a hard proof... [...] >"When they combine Einstein’s gravity equations and the equations of electromagnetism, they calculate that a black hole’s charge, Q, can never surpass its mass, M, when both are converted into the same fundamental units. Together, the black hole’s mass and charge determine its size — the radius of the event horizon. Meanwhile, the black hole’s charge also creates a second, “inner” horizon, hidden behind the event horizon." Super weird idea here... if we thought about a black hole of whatever size holographically, as information, then what would be true if the inner, hidden part of the black hole actually contained a miniature replica, a miniature mirror-image -- of ALL of the information inside this universe, a universe-inside-of-a-universe? That's highly speculative of course, but I think it's an idea worth exploring... [...] ">When a black hole hits this point, a simple option for further decay would be to split into two smaller black holes." You mean like + and - on a battery terminal? Let me go for "full crackpot theorist" <g>... What if charge, as we know it, in electricity, is implemented by various clusters of small black holes, regions of curved space, that we have (up until this point in time) been calling by such names as "charge", "electron", "electricity", "potential", "potential difference", etc. When, what you've got might be multiple black holes, split into pairs, where one is a complex conjugate, a mirror image of the other, and they basically want to unify and annihilate, producing various wavelengths (heat/information) in the process? All physics should be solvable once the correct identities are established between apparently dissimilar phenomena...

cjfd 6y ago
Sure, one can speculate that. There is quite a lot of devil in the details, though. One thing that is a bit unclear when it is 'all curved space' is how one would ever get spin 1/2 particles, i.e., non-integer spin particles. E.g., in string theory one has to invent a 'fermionic string' to get them otherwise one only gets integer spin particles. Also it is not clear how 'multiple black holes' are going to be a stable configuration together.
- peter_d_sherman 6y ago
  I'm not saying I'm right... I'm just saying "it may be worth exploring..." Nothing more, nothing less! <g>
  - ngold 6y ago
    I had fun.
  - qubex 6y ago
    There’s plenty of ‘exploring’ going on. The famous “ER = EPR hypotheis” suggests that entangled particles are opposite ends of a wormhole.
- wrnr 6y ago
  I always thought that the non integer spin was more of an historic artefact, because they measured the photon first. Not my area of expertise, but does the half spin have any meaning?
  - wnoise 6y ago
    Well, it acts quite a bit like an angular momentum of that amount, including obeying conservation laws jointly with regular ("orbital") angular momentum. I don't know of a good way of explaining the half-integral nature without diving into representation theory. The short story is: 1. Conservation laws and continuous symmetries are the same thing. The standard explanation of this is when we move or turn the system, the rules it obeys are the same. Or alternately change our view of the system by picking different origin and axes for our coördinate systems, the form of the rules (how to evolve, how to measure, how to predict) remains the same. This is Noether's theorem. 2. But symmetries don't mean our description of a system is unchanged. It means that our descriptions must change in a compatible way with our new point of view. 3. Cashing this out in math, symmetries are groups acting on states. Having the states transform compatibly means these actions must be "linear representations of groups". 4. A spin-one object has the wave function (normally considered the fundamental state) act like a vector under rotations, and because symmetry under rotation is angular momentum, this must be too. 5. When we do this quantum mechanically, all of our predictions come from the density matrix, where the wave function enters twice (as an outer product). A spin-1/2 object has the density matrix transform like a vector, and the wave-function itself transforms "like a spinor", which is to say, itself.

mormegil 6y ago

> In that case, the universe of the far future will be littered with tiny, indestructible black hole remnants — the remains of any black holes that carry even a touch of charge I don't get that. Wouldn't the charge be neutralized by consuming particles with an opposite charge (which are attracted gravitationally and electrically)? Or even by merging two extremal black holes with opposite charge?

hellofunk 6y ago
I think if you read the article, they talk about this far future hypothesis.

at_a_remove 6y ago

Here's the one that has bugged me since I first learned of Hawking radiation as an undergrad: if it is true (it's still unobserved but let's go with it), that means that merely passing through the event horizon allows for violation of the conservation of baryon number. I generally regard most of the "Star Trek physics" ideas like FTL with the hairy eyeball, but this one really gets me. Being able to violate the conservation of baryon number (and lepton number, for that matter) would point to -- in some scenarios -- mass-energy conversion being a lot more available than the laborious processes of fission, fusion, and particle/antiparticle mutual annihilation.

simonh 6y ago
Surely the conservation of baryon numbers is just a rule for reactions. I don’t see how crossing the event horizon changes anything. Remember from the POV of the baryon, it never crosses the event horizon. It’s not really ‘destroyed’, it just becomes unobservable to the external universe.
- qubex 6y ago
  True, but from the point of view of an observer at infinity, the baryon falls and comes to a halt, while the event horizon of the black hole expands and encompasses it (or would, if you could measure the diameter of the black hole with sufficient precision). This is just the essence of the information paradox, expressed in terms of baryon and lepton numbers. Either the Hawking radiation that comes out is ‘correlated’ with the matter that fell in (meaning that black holes have hair) and information is preserved, or they’re not, and information is destroyed. That’s literally the crux of the matter.
  - simonh 6y ago
    That’s a good point, I wasn’t thinking about it in terms of the information paradox, but then the recently proposed solutions look like they have a good chance of panning out. https://en.wikipedia.org/wiki/Black_hole_information_paradox#Recent_developments https://en.wikipedia.org/wiki/Black_hole_information_paradox... But anyway I still don’t think this is really an issue regardless. The same could be said of the cosmic event horizon. Vast swathes of the universe are unobservable and causally disconnected from us due to the expansion of the universe separating us at faster than the speed of light. Again, no Baryons are being destroyed in this process, they’re just becoming unobservable _to_us_. https://en.wikipedia.org/wiki/Event_horizon#Cosmic_event_horizon https://en.wikipedia.org/wiki/Event_horizon#Cosmic_event_hor...

andrewflnr 6y ago

I remember reading somewhere that charged black holes would quickly lose their charge by radiating charged particles rather than, I guess, purely neutral photons. I've been taking that for granted for a while now, but don't remember exactly where I read it. Does anyone know where that hypothesis comes from and how it relates to the work in article?

qubex 6y ago
I think the prevailing notion is another, namely that an electrically charged black hole would quickly neutralise by preferentially attracting particles of opposite charge.
- AnimalMuppet 6y ago
  In particular, if a charged black hole creates Hawking pairs, the oppositely-charged particle is more likely to be captured than the same-charge particle.
- wnoise 6y ago
  Once Hawking radiation is produced at all, those are the same process.

pierrebai 6y ago

As a true amateur,I don't understand the basic premise of this extremal black hole mystery. In my simple view, if a charged black whole is extremal and cannot shrink then... the solution simply is that it must grow again. It absorbs particles of the opposite charge until it becomes neutral enough to shrink again and the process repeat until it completely evaporate. That seems both a simple and straightforward theory. (Then my other misunderstanding is how a black whole would become so charged when the universe is seemingly so neutral. The law of big number ensures that a black hole would be mostly neutral and the extremal case would only happen for very small ones on the brink of evaporation.)

zzv 6y ago

What a ridiculously well-written article!