[HN Gopher] In New Paradox, Black Holes Appear to Evade Heat Death
___________________________________________________________________
In New Paradox, Black Holes Appear to Evade Heat Death
Author : theafh
Score : 93 points
Date : 2023-06-06 13:57 UTC (9 hours ago)
(HTM) web link (www.quantamagazine.org)
(TXT) w3m dump (www.quantamagazine.org)
| jareklupinski wrote:
| Maybe black holes were torn in spacetime by advanced
| civilizations in previous iterations of the Universe in an effort
| to escape their own Universe's heat death
| BudaDude wrote:
| This sounds like a great premise for a sci-fi novel
| pelagicAustral wrote:
| Indeed, I just ask ChatGPT to write me a story using this
| premise and it was gold.
| haneefmubarak wrote:
| Please share with the class, what did our dear AI come up
| with?
| jareklupinski wrote:
| "To Hitch a Ride on a Dying Star" will be the title :)
| SomeCallMeTim wrote:
| Reading about how, over time, the volume of a black hole seems to
| grow infinitely makes me immediately jump to an obvious
| connection:
|
| The universe as a whole is ALSO a system that appears to grow
| infinitely.
|
| I mean, there have been many conjectures that a black hole could
| contain a new universe, and that the creation of a black hole
| also creates a new universe. This would seem to hint at another
| potential connection.
|
| That said...I'm really not a physicist, so maybe that connection
| is at best a hook for a science fiction story. But it surprises
| me that the article didn't even mention the parallel.
| Freestyler_3 wrote:
| I like that idea, a bubble has small bubbles inside. All of
| them growing, but one inside it is growing more, and it "eats"
| the others until it consumes the bubble it is in, and then it
| pops and all matter starts moving from center outwards.
|
| Now we need to find some way to prove this is real.
| hinkley wrote:
| I'd be willing to put $100 on longbets to say our universe is
| inside a singularity, but I doubt anyone who remembers I
| existed will still be alive when we figure it out.
| moffkalast wrote:
| You best bet some future physicist doesn't also figure out
| how to reverse entropy, or they'll be back to collect on that
| bet.
| ben_w wrote:
| You can't be inside a singularity because that's a point, but
| we are inside (surrounded on all sides by) an event horizon.
| boringuser2 wrote:
| What proof exists for this hypothesis?
| pdonis wrote:
| _> over time, the volume of a black hole seems to grow
| infinitely_
|
| Unfortunately, the article fails to note that this is a
| speculative _hypothesis_ with which not all physicists agree.
| It 's not an established fact. It's not even an established
| theoretical prediction.
| cyberax wrote:
| So they're integrating across a singularity to compute volume?
| That's always a bad idea.
| RecycledEle wrote:
| May someone who does not understand any of this ask a question?
|
| Years ago scientists made small black holes here in Earth, and,
| while I was screaming in protest, they assured me they would not
| fall to the center of the Earth and slowly eat us all. They
| assured us those black holes would evaporate.
|
| Has anything changed? Should I be worried?
| drdeca wrote:
| In addition to what the other reply points out (that the LHC
| and such are not sufficient to produce a black hole), another
| calculation I've seen shows that, even if it had produced a
| black hole with mass given by the energy of these collisions,
| and even if these black holes had started at rest with respect
| to the earth, and like, fallen into the earth (and started
| oscillating around the center), and if they did not evaporate
| (say, if Hawking radiation wasn't actually a thing), then the
| amount of time needed for them to swallow any appreciable
| amount of matter at all, would be very very long, and so would
| not actually cause any problem for the forseeable future.
|
| (not that any were created. The detectors would have noticed.
| But even if they had been created, it wouldn't have been a
| problem, even if we are wrong in thinking that they would
| immediately evaporate.)
|
| The thing is, if the black hole is made from something of a
| given mass, then, well, it only has the amount of gravitational
| attraction associated with that quantity of mass. And, that is
| a very small amount unless the-thing-to-be-attracted is very
| very very very close to it, and, a point particle falling
| through the earth wouldn't be likely to get that close to many
| atoms.
|
| Ok, found the link I read this on :
| https://4gravitons.com/2023/01/27/lhc-black-holes-for-the-te...
|
| He says that it would take 10^67 years for the black hole to
| double in mass.
|
| So.... Not really a problem.
| beecafe wrote:
| No black holes have ever been produced on Earth
| devoutsalsa wrote:
| Scientists have not made black holes here on earth. The energy
| required to do this is insanely higher than anything we are
| currently capable of. Even at the LHC we aren't even hitting
| the energy levels of cosmic rays hitting out own atmosphere.
| These aren't the most reputable sources, but you'll get the
| basic idea...
|
| https://www.scientificamerican.com/article/has-anyone-create...
|
| https://www.forbes.com/sites/startswithabang/2019/08/23/cosm...
| passion__desire wrote:
| So Roger Penrose was right all along. CCC.
|
| This[0] is a nice overview lecture by Scott. Lenny and Scott were
| exploring these ideas long time ago.
|
| [0] Scott Aaronson: Black Holes, Firewalls, and the Complexity of
| States and Unitaries https://www.youtube.com/watch?v=zJdTtL3ajaI
| denton-scratch wrote:
| > Once they cross the event horizon, they are moving at the speed
| of light toward certain doom.
|
| Can that be correct? I thought the falling man experienced no
| change on crossing the event horizon (other than the effects of
| spaghettification, which begins long before arriving at the
| horizon).
|
| I thought that you'd continue accellerating toward the
| singularity, asymptotically approaching both the speed of light
| and infinite inertial mass. Am I wrong?
| samstave wrote:
| When I was in 7th grade we were learning about Black Holes -
| and the movie "Explorers" had come out where the kids are able
| to make a forcefield sphere surrounding an abandoned car from a
| carnival ride/roller coaster --- and they fly into space and
| meet aliens and stuff...
|
| Welp - 7th grade me postulated that if you had one of those
| force spheres, and you could accelerate at the same rate or
| slightly faster than the speed at which matter is pulled into a
| black hole, could you stay ahead of the gravity wave and "surf"
| it safely into the black hole?
|
| https://www.youtube.com/watch?v=al75vXD6koc -- Trailer
|
| https://www.youtube.com/watch?v=RqQKGxrfwsk -- Trivia
| [deleted]
| downWidOutaFite wrote:
| No reason you would continue accelerating. Seems like you would
| would reach a stable speed while orbiting inside the event
| horizon.
| vikingerik wrote:
| No - this doesn't happen, because the speed required for a
| stable orbit would be greater than the speed of light.
| pdonis wrote:
| _> Can that be correct?_
|
| The "towards certain doom" part is correct. The "at the speed
| of light" is not. Unfortunately this kind of thing is typical
| for pop science articles.
|
| _> I thought the falling man experienced no change on crossing
| the event horizon_
|
| That's correct. The infalling person has no way of knowing,
| locally, that they have crossed the horizon and are now doomed
| to hit the singularity. But that doesn't change their doom.
|
| _> (other than the effects of spaghettification, which begins
| long before arriving at the horizon).*
|
| Not for the typical black holes we observe in the universe.
| Tidal gravity at their horizons is too small for
| spaghettification; that doesn't happen until the infaller is
| well inside and approaching the singularity.
|
| _> I thought that you'd continue accellerating toward the
| singularity, asymptotically approaching both the speed of light
| and infinite inertial mass. Am I wrong?*
|
| Yes. None of these things are true. Your acceleration is zero--
| you're in free fall. There is no well-defined notion of "speed"
| at all, but your worldline remains timelike. Your inertial mass
| is unchanged. And, finally, the singularity is not a place.
| It's a moment of time. You can't "accelerate towards" it any
| more than you can accelerate towards next week.
| denton-scratch wrote:
| > Your acceleration is zero--you're in free fall.
|
| So if I jump out of an aeroplane, I don't accelerate towards
| the ground? Apparently my understanding of the natural world
| needs some enhancements.
| AdamH12113 wrote:
| > So if I jump out of an aeroplane, I don't accelerate
| towards the ground?
|
| In a very real sense (although not a useful one for a
| skydiver), the answer is yes. This is a key insight of the
| Equivalence Principle and the curved-spacetime view of
| gravity. You (in free-fall) are on an inertial "straight
| line" path through spacetime towards the center of the
| Earth. When you reach the ground, it pushes on you, messily
| accelerating you off of that path.
| ninkendo wrote:
| Nope, you're in an inertial reference frame when in free-
| fall. Ignoring air resistance, if you were to take an apple
| out of your pocket and place it next to you in mid-air, it
| would be motionless relative to yourself. Put a box around
| you with no windows and you'll have no idea whether you're
| floating through space in the absence of gravity, or if
| you're free-falling inside a gravity well.
|
| This is the main difference between general relativity and
| the newtonian notion of gravity: GR says gravity is just
| spacetime curvature, and by following an inertial
| (geodesic) path through spacetime, it _appears_ to be
| acceleration to certain observers, but is in fact inertial.
| Newtonian mechanics says instead that gravity is a force
| and you 're indeed accelerating, but it's a view that
| breaks down at high mass/speed, and GR makes correct
| predictions where Newtonian mechanics does not, so we
| generally prefer the GR interpretation.
| smallnamespace wrote:
| > you're in an inertial reference frame when in free-
| fall.
|
| But the falling person's frame isn't the only one
| available. Someone on the ground would rightfully
| describe the falling person as accelerating towards the
| ground (or them) (at least until they reach terminal
| velocity).
|
| The most important lesson of relativity is that _no
| reference frame is privileged_. That means both
| descriptions are valid, provided you attach the reference
| frame to the description.
| pdonis wrote:
| _> The most important lesson of relativity is that no
| reference frame is privileged._
|
| No, the _most_ important lesson of relativity is that
| _only invariants are physically meaningful_. IIRC
| Einstein once commented that he wished his theory had
| been called the "theory of invariants" since that would
| have been a better description of its most important
| feature.
|
| The _second_ most important lesson of relativity is that
| yes, you can use whatever frame you wish, _because_
| invariants are the same no matter what frame you use to
| calculate them. So you will come up with the same
| physically meaningful quantities no matter what frame you
| choose.
| 867-5309 wrote:
| all this talk of GR and invariants, not to confuse a
| mathematical singularity with a gravitational one, at
| which point GR itself breaks down per the need for a
| quantum mechanical description. the truth is we don't
| know what happens within a black hole, and probably never
| will
| pdonis wrote:
| _> GR itself breaks down per the need for a quantum
| mechanical description_
|
| This is the current predominant belief among physicists,
| yes, but that doesn't mean it's established fact.
|
| _> the truth is we don 't know what happens within a
| black hole, and probably never will_
|
| This is way too pessimistic. The predictions of GR for
| this regime are precise and unequivocal. Even if you
| believe GR breaks down when spacetime curvatures reach
| the Planck scale (which is the current predominant
| belief, as I said above), that still leaves _most_ of the
| black hole 's interior within GR's domain of validity.
| akomtu wrote:
| Falling in a black hole is a different experience. It must
| be more like being squeezed in a narrow tube with a glowing
| light that was once the universe on one end of the tube and
| something indescribable on the other end. Perception of
| time will change too, as all the particles that let us
| perceive the time will be messed up in strange ways.
| Perhaps time will seem multidimensional or there will be
| many timelines. In other words, your perception of a fall
| from an aeroplane isn't true or absolute, it's mediated by
| particles that define, for you, space and time, and if
| those particles get messed up, your reality will change
| completely.
| pdonis wrote:
| None of what you say is correct as a description of what
| General Relativity says will happen to someone who falls
| into a black hole.
| pdonis wrote:
| _> if I jump out of an aeroplane, I don 't accelerate
| towards the ground?_
|
| Not in your rest frame. In your rest frame, the ground
| accelerates towards you.
|
| However, the acceleration described in both frames (yours
| and the Earth's) is coordinate acceleration, which is
| frame-dependent, and in relativity frame-dependent
| quantities don't have any direct physical meaning. The
| quantity that has physical meaning in terms of acceleration
| is proper acceleration--what an accelerometer strapped to
| you would read--and in free fall that is zero.
| FrustratedMonky wrote:
| Typically I thought Quanta magazine did better than typical
| pop-science. Guess this was an exception?
| beebeepka wrote:
| > That's correct. The infalling person has no way of knowing,
| locally, that they have crossed the horizon and are now
| doomed to hit the singularity. But that doesn't change their
| doom.
|
| This is what happened to SG-10.
| smallnamespace wrote:
| It's pretty clear GP was using the reference frame of a far-
| away observer.
|
| It's fine to switch to the infalling observer's frame, as
| you're doing here, but that choice isn't objectively any more
| correct than GP's. For example:
|
| > Your acceleration is zero--you're in free fall.
|
| That's in the falling observer's frame. It's totally fine to
| say 'a astronaut in freefall is accelerating towards the
| earth', explicitly invoking Earth's reference frame.
|
| The freedom to choose a frame is literally why it's called
| 'Relativity'.
| pdonis wrote:
| _> It 's pretty clear GP was using the reference frame of a
| far-away observer._
|
| Even in such a frame (for example, Painleve coordinates),
| not all of the statements are correct. In those
| coordinates, the infaller's coordinate acceleration is
| nonzero, as you say, but their coordinate _speed_ inside
| the horizon is _greater_ than the speed of light. Their
| inertial mass is still unchanged. And the coordinate
| acceleration in this frame is still not "towards" the
| singularity, since the singularity is still a moment of
| time, not a place in space.
|
| _> It 's totally fine to say 'a astronaut in freefall is
| accelerating towards the earth', explicitly invoking
| Earth's reference frame._
|
| In terms of _coordinate_ acceleration, yes. But coordinate
| acceleration, precisely because it is frame-dependent, is
| not considered a physically meaningful quantity in
| relativity. Only invariants can be physically meaningful
| quantities. _Proper_ acceleration--what an accelerometer
| attached to the infaller reads--is an invariant, and that
| is zero for a free-faller.
| ryanSrich wrote:
| I can't accelerate towards next week, but I can predict when
| next week will happen, with extreme accuracy. Is this the
| same for reaching the singularity? Does the person falling
| (for the sake of this example let's assume they maintain
| consciousness) experience the passing of time as they fall
| further "into" the black hole? If so, how long would one
| experiencing the falling until they reach the singularity?
| jleahy wrote:
| Yes, and you can calculate exactly how much time it takes
| (it was an exam question in my final exams for undergrad
| iirc). The amount of time depends on the mass of the black
| hole but it's definitely less than a minute.
| ben_w wrote:
| I'd always assumed that for TON 618 it would've been a
| few days... but I don't have a physics degree, and now I
| come to write this comment realise I'd been just
| presuming it was "Schwarzschild radius/c" and it's not
| _necessarily_ going to be such an easy result.
| russdill wrote:
| You certainly can accelerate to next week as measured by
| Earth calendars. Climb into your local particle accelerator
| and ask them to get you accelerating around the loop as
| close to the speed of light as possible. By accelerating,
| you can get to next week in just a few seconds of your own
| subjective time.
|
| Also, you can accelerate towards the black hole singularity
| and get there faster.
| didgeoridoo wrote:
| I'd love to understand the interaction effects between 1)
| acceleration toward singularity (prob approaching c?), 2)
| gravity (prob approaching infinity?), 3) distance
| compression experienced by infalling observer.
|
| My instinct is that the observer would subjectively
| experience it to take exactly the time predicted by
| classical mechanics to "hit" the singularity -- basically
| that all the considerations above would cancel out in the
| local reference frame -- but that to an outside observer it
| would take an infinite amount of time.
| zmgsabst wrote:
| There's a fairly obvious connection:
|
| Braiding is equivalent to circuits, as shown by Microsoft's idea
| for a topological quantum computer.
|
| If you start a system braiding, it will build complexity because
| braiding appears to be non-local -- and so the tangle becomes an
| increasingly complex circuit. The cusp of a black hole is a
| regime we'd expect such topological effects to accumulate.
|
| AdS/CFT suggests that maybe there's something deeper to the
| relationship between braiding in spacetime and quantum systems.
| Indeed, braiding is one of the few ways we know to generate
| quantized properties within a continuous geometric setting.
| SanderNL wrote:
| Your comment raises important points. The non-local nature of
| braiding in topological quantum computing contrasts with the
| inherent locality of the AdS/CFT correspondence, prompting us
| to wonder how these paradigms might coexist.
|
| Could braiding and entanglement entropy, both non-local quantum
| properties, hint at new understandings in the AdS/CFT
| framework? Additionally, might these braided structures help
| illuminate the microstate structure of black holes as theorized
| by string theory?
|
| Finally, your insight into quantized properties emerging from
| continuous geometry recalls how quantum field theory has been
| linked to knot theory. Can we use these ideas to further probe
| the quantization of spacetime?
|
| Your reflections beautifully intertwine quantum computing,
| holography, and quantum gravity, encouraging us to weave
| together these disparate strands in the tapestry of theoretical
| physics.
| uoaei wrote:
| > If you start a system braiding, it will build complexity
| because braiding appears to be non-local -- and so the tangle
| becomes an increasingly complex circuit. The cusp of a black
| hole is a regime we'd expect such topological effects to
| accumulate.
|
| Would you please expand on the connections between the first
| and second sentence here? What does braiding 'look' like in
| topological spacetime?
| sdfghswe wrote:
| Meaningless word salad.
| dustingetz wrote:
| "system braiding" - what is the wikipedia or googleable term
| for this?
| CaptainNegative wrote:
| I don't understand how this is obvious -- non-locality does not
| inherently imply that iteration increases complexity. For a
| concrete not-entirely-trivial counterexample, von Neumann's
| middle-square method also appears "non-local" (in that every
| output bit is a function of a majority of the input bits
| including well-separated ones) but famously tends to converge
| to short orbits if not a single constant value.
| ChatGTP wrote:
| Blackholes and Microsoft...
| didgeoridoo wrote:
| Obviously!
| EddieEngineers wrote:
| This feels like what GPT-4 would say on the Rogan podcast after
| mushrooms
| jiggawatts wrote:
| I asked GPT-4 to pretend it's on shrooms and talking about
| these topics: https://chat.openai.com/share/b76b8139-4224-4de
| 7-87ce-0e2a3a...
| EddieEngineers wrote:
| > Let's talk about braid theory. In the quantum world,
| particles can be thought of as strands, and their
| interactions as braids. The braids weave and loop around
| each other, creating intricate patterns, a dance of
| existence. Each unique pattern, or braid, represents a
| different state of the particle. The magic is that the
| braids can't get tangled.
|
| That is not too far off hahahaha
| aaroninsf wrote:
| If I could give HN comments reddit awards, I'd start with
| this one.
___________________________________________________________________
(page generated 2023-06-06 23:01 UTC)