Cracking a Black Hole Paradox - Sixty Symbols

Researchers may have used wormholes to solve the so-called "Black Hole Information Paradox", as Tony Padilla explains.
More links and info below ↓ ↓ ↓
More Black Hole videos: bit.ly/Black_Hole_Videos
More Tony Padilla videos: bit.ly/Padilla_SixtySymbols
Papers and reading from this video:
Replica wormholes and the black hole interior
inspirehep.net/literature/176...
Replica Wormholes and the Entropy of Hawking Radiation
inspirehep.net/literature/176...
The entropy of Hawking radiation
arxiv.org/abs/2006.06872
Black holes and quantum information
www.nature.com/articles/s4225...
Tony Padilla is a professor at the University of Nottingham.
Also catch Tony on Numberphile: bit.ly/Padilla_Numberphile
Visit our website at www.sixtysymbols.com/
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This project features scientists from The University of Nottingham
bit.ly/NottsPhysics
Patreon: / sixtysymbols
Sixty Symbols videos by Brady Haran
Artwork by Pete McPartlan
www.bradyharanblog.com
Email list: eepurl.com/YdjL9

[@frostyusername5011]

Brady is on point with his interview questions, truly a master in his art.

[@thenasadude6878]

We should grant him the Master of Deduction Award (Defi Brilator, JoJo on crack)

[@RitusG]

He has a brilliant way of setting up the right questions. Always seems to hit on exactly what questions I have while watching.

[@conanichigawa]

I agree.

[@realworld912]

I always think this

[@magilmart]

I was going to comment the same. I am often amazed at how he always gets to understand difficult concepts in real time from so many different areas and how insightful his questions are. Probably an IQ over the roof.

[@Malakawaka]

Next video: imaginary time

[@ujjwaLoL]

Have you read a brief history of time If you haven't (quite unlikely) i suggest you read it It mentions imaginary time in last few chapters

[@Malakawaka]

@@ujjwaLoL Thanks, I actually did read it many years ago, but I don't remember it talking about imaginary time and related to time disappearing through black holes and the relationship with wormholes. Anyway I think it would be interesting to re read it. Especially interesting is to think if time comes out on the other side of the wormhole

[@sujimtangerines]

Yes please! I'm not well-versed enough to do a deep dive via the book mentioned above and I seem to learn pretty well, even at 50, using the analogy technique especially in video format... Which is why I really appreciate all of Brady's channels!!

[@S1nwar]

in a "a universe in a nutshell" by hawking it was described as basically a coordinate that counts across all the parallel universes, at a fixed point of real time in those universes

[@thenasadude6878]

More like an album title for some band like the Muse

[@peppybocan]

Worm hole through the black hole. That's a deep rabbit hole.

[@lewsdiod]

Holes all the way down, buddy! 🌪🌪🌪💦

[@channelwarhorse3367]

Honestly using gravity induction engine the graphic gave the concept of device utilization. To induct biology through Event Horizon to center is complicated. Mechanically applicable. Rs

[@channelwarhorse3367]

Honestly using gravity induction engine the graphic gave the concept of device utilization. To induct biology through Event Horizon to center is complicated. Mechanically applicable. Rs

[@ozzymandius666]

Leonard Susskind solved this years ago.

[@channelwarhorse3367]

@@ozzymandius666 Rs. No faster then light or frame of reference of mass energy content generation of space. Sub c and g to zero. You know faster then light. Applied Relativel, use exact solution to GR. U wish.

[@jrr4166]

Imaginary time is time spent watching Sixty Symbols instead of working....

[@CreepsCompilation]

Exactly... These pseudo science channels constantly spew out theoretical assumptions with ZERO factual observations to PROVE any of them..

[@David_Last_Name]

@@CreepsCompilation Ummm.... You do realize that this is an interview with an ACTUAL, published theoretical physicist, right? He isn't "spewing" anything, he is giving a genuine breakdown of a real physics paper. When he says "in my opinion", that is the opinion of an expert, not a lay person. Contrast that to the "spewing" which is done in the comments section.

[@usr7941]

@@David_Last_Name lol that blind faith

[@David_Last_Name]

@@usr7941 what blind faith? Feel free to type your answer into that magical box which let's you instantly communicate with anyone in the world using invisible waves. Then tell me who discovered the tech which makes it work. Thanks.

[@Mia-ln1zs]

@@usr7941 I wouldn't call it blind. That said I tend to put little weight in titles. The arguments, reasoning, and/or points are what's important. Don't care if you're a "published theoretical physicist." You can still be in error. Not that the guys in the video are "spewing" anything.

[@lopzag]

"One less elephant in the solar system"

[@thenasadude6878]

For what we know, there's a small chance that the Oort cloud is 95% pure elephants

[@SlimThrull]

@@thenasadude6878 Naw, it's all jackalopes.

[@davidwuhrer6704]

It's teapots, surely.

[@d5uncr]

That's not a big problem, unless it's one of the elephants standing on the turtle and holding up the Disc...

[@HiAdrian]

A tragedy surely.

[@flymypg]

Tony's enthusiasm is beyond awesome. This video is one example, second only to his reactions during his visit to CERN. I've listened to way too many scientists who had passion, but were totally unable to share or communicate it. Tony spends days doing the work, finds personal joy, then shares the mix with us. We are fortunate beyond all reason.

[@scotttroyer]

And now we need a video on imaginary time.

[@LateNightHacks]

it's the time you have between a task and it'd deadline...

[@MegaManki]

Imaginary time is just a dirty mathematical trick physicists use to make things finite. It's not a "real" thing.

[@tinfoilhatseller]

@@LateNightHacks 😆😆😆😆

[@seeseefok7659]

root of -1 time

[@adm0iii]

It happened on imaginary last Tuesday.

[@SmartAlx]

Brady, you are sooo GREAT at asking AMAZING questions!

[@InternetStranger476]

i love his animations lol

[@treyquattro]

that's the real elephant

[@Macieks300]

Emma Watson is one of the last names I would've expected in a Sixty Symbols video.

[@Thisisahandle701]

Gucci Mane

[@NoNameAtAll2]

when was it said?

[@bbbl67]

If Dr. Becky Smethurst was still working on these videos, then she'd be dropping Emma Watson references everywhere.

[@bbbl67]

@@NoNameAtAll2 Starting around 18:50

[@lukesnyder1036]

Wamma Etson?

[@etiennedud]

So... We have found a solution but it is too early to be easy to understand without looking at the math Cool stuff none the less

[@pafnutiytheartist]

I think you relied very heavily on analogies. I understand that it's a cutting edge science and difficult to simply, but I would like to see something slightly more technical.

[@matbroomfield]

Yeah, the art gallery house was appalling.

[@suivzmoi]

uggh completely unnecessary analogy. just say the information is preserved after all and we can inspect it using wormholes.

[@sparkmagea99]

He linked the papers in the description, go after it my friend.

[@dosomething3]

I liked the analogy. It’s very difficult to get your stuff back. But it can be done

[@JJohnMatt]

Check out Maldacena's strings 2020 talk on youtube. It explains the technical terms. It might be too technical, but I think there are enough pictures to get an idea of what's going on.

[@alan2here]

Quantum Entanglement over the event horizon. Quantum Entanglement over the… Each subatomic particle gets it's own wormhole. 🤷🏻‍♂️ ok. Sort of a classical version of entanglement.

[@non-inertialobserver946]

Look up ER=EPR

[@alan2here]

Thank You :) Nice. It brings Entanglement, Wormholes (including these tiny particle pair ones), and "entanglement graph (network) is space graph" together nicely. It would mean each subatomic particle is part of a lot of entanglements pairs.

[@TheBackyardChemist]

@@alan2here My jaw is kinda dropping, this is remarkably similar to what was portrayed in the sci-fi novel Diaspora by Greg Egan.

[@alan2here]

You may also like Greg Egan's, Shild's Ladder. I like this thread. :)

[@thenasadude6878]

If each particle has its own wormhole, the the black hole suddenly has a lot of hair

[@Daxtahfakenham]

So glad Brady asks the questions he does. Really helps break the ideas down imo

[@serversurfer6169]

Initially it sounded like he was saying that the information wasn’t lost because it remained trapped in the black hole, but theoretically you could peek at it through these wormholes. But if that’s the case, what happens when the black hole evaporates completely? Wouldn’t the information be lost at that point? Like, when the mansion burns down and takes the paintings and dilettante with it? 🤔 But then it sounded like the information actually escaped through these wormholes. But if that’s the case and they don’t form until half of it has evaporated, does that mean the first half of the radiation escapes with no information about its origin, and half escapes with double information? 🤷‍♂️ And what does it even mean for “half” of a black hole to evaporate if they can be of arbitrary size and even grow during their lifetime? 🤪

[@patrickgreen1656]

I'm guessing half the "information/data" is outside the black hole, but it's impossible to even start making sense of it till you get a bit more than half of the "data". The point is the rest of the information is still in the black hole and not deleted, because it does all eventually come out.

[@IntraFinesse]

I was thinking the exact same questions. Do these wormholes lead to this "island" that is not in our universe? So the interior of a black hole is in a different dimension, lets say the 5th dimension, and the information remains there forever? Can a wormhole be destroyed so there is a permanent loss of information?

[@benp9793]

@@IntraFinesse What do you mean? You do realize that "dimensions" are just the different ways directions in space that we can move. It isn't the sci fi idea of alternate realities. For instance, we perceive the universe as 3d, because we have 3 spatial dimensions, left and right, up and down, and forward and backwards. a 5d world would just be another direction of movement.

[@acecreation4770]

Maybe the half size evaporation was for the case when a backhole is dormant, but still in any case it looks like half the information will be lost 🤔

[@smokey04200420]

You’re giving it much more thought than it deserves. It’s just more nonsense science fiction.

[@elave16]

The notion that two particles are created and then separated is a very simplified one. If anyone wants to dive a little more on the theory pbs spacetime has an excellent video using the concept of posible wave lengths when horizons occur and also a nice explanation of the unruh radiation

[@Jhymnbeau]

Indeed. As the two particles involved are, though, entangled, then the quantum state of the free particle should briefly yet accurately reflect the quantum state of the trapped particle. Already, the black hole is leaking information, no matter its size.

[@deandeann1541]

James - I'm not sure that counts as information in the physics sense of the word. Note that two entangled particles cannot be used to transmit information between points in normal space. When you measure an entangled particle's spin it is still random. I don't believe it would be any different just because one particle is within the black hole, there is still no transmission of information.

[@jfbeam]

@@deandeann1541 It _seems_ random to us because we don't understand how to control spin state, or what mechanism causes it to change. None the less, when you measure an entangled particle you know something about the state of another particle -- inside a blackhole or not.

[@kellymoses8566]

It is fundamentally wrong because it would mean that hawking radiation intensity would be proportional to the surface area of the black hole, but it is actually the opposite.

[@jfbeam]

It's also the Sci-Fi phenomenon of "vacuum energy". While we've not actually gone up to a blackhole to see what's all is going on, we're pretty sure anti-matter isn't being created at the event horizon. If this spontaneous creation-and-annihilation were true, statistically 50% of the time the anti-particle would be would be on the outside. (which would go on to collide with normal matter in the universe, which would be bad for everyone.)

[@costa_marco]

Brady, your questions are not stupid. They are really pertinent and on point. Keep up with the good work!

[@MisterMajister]

Brady always asks such great questions! I love it!

[@jojojorisjhjosef]

lmao, Tony's face 6:14 is like "shit he got us"

[@thetruthexperiment]

Yeah. You’re absolutely right.

[@jazzabighits4473]

@@thetruthexperiment Not really, how are you going to account for every elephant on the planet, let alone every single quantum particle/state in the universe?

[@hayder978]

Two issues: 1. If we have multiple growing black holes, how can we know this one fed on the missing elephant and that one on the missing car.. 2. In order to 'remember' old information so you will know what had been missing, you need to copy information. When black hole destroyed one copy, even if we have the 2nd copy, but still there is information lost if the 1st copy destroyed. The problem is that information shouldn't be destroyed even if we have a 2nd copy of it.

[@aiberengi]

@@hayder978 1) feels like you're trying to pivot away from answering the simple scenario (one black hole in the entire universe) by introducing multiple black holes. what's the answer for the simple scenario? 2) the problem isn't that the elephant/car is destroyed. the problem is that, given just the black hole, we don't know whether it ate an elephant or car. but we *do* know, because we have a catalog of everything in the universe. why doesn't this work? i'm still not satisfied by the prof's answer.

[@dinos372]

Always excited to watch a video with professor Tony

[@maitland1007]

Brady your questions are my favorite part of your videos.

[@oafkad]

I love Brady's thinking face. His gears are chugging along at such a high pace.

[@Mck6]

The painting analogy was completely pointless. It didn't explain how the information gets out of the black hole at all. The point of analogies is to assign an easy to understand point of reference for each part of a complex system. What is the guy with the paintings? What are the paintings? Are the parties integral to the analogy? How are the townspeople the radiation when no part of any townsperson goes inside/comes out of the mansion? You already explained how the radiation works in the first part of the video and assumed everyone understood that (otherwise you'd start with the analogy). There's no need to a convoluted analogy to say "the radiation actually has some information connected to it". In fact, the most integral part of how the information can get out (the wormholes) aren't even a part of the analogy!

[@RicardoPenders]

everything they do is pointless!

[@thenasadude6878]

But singularity are point like

[@coryc9040]

Agreed. This was a half baked video. Would have been just as useful to have a 10 second video where he says "how do we solve the information paradox of a black hole: wormholes" and I would have learned as much.

[@lit3plumber12]

I understood the analogy but it was an overdrawn one. As I was hoping for a simple one, he showed the headphones, so I'm satisfied with that.

[@TheFrozenthia]

I understood the analogy and references. I guess it's not really for a layman's explanation for the radiation but I did understand the connection.

[@iambiggus]

Tony is great. Always enjoy his interviews and his genuine enthusiasm.

[@kennethhicks2113]

This helps in explaining entanglement. Ex. A virtual particle pair appears. They have to be entangled. One goes in event horizon. WHEN detected on information island, the info is transferred to the outside particle. Entanglement is a wormhole. Unidirectional information exchange (but in either direction ; ). Entropy teleportation, um (entropy conserved). Guess the only question left is, "What is time?".

[@luvo47]

😭i missed sixty symbols content

[@tobiasthrien1]

6:08 remember the time order of what is happening. of course if you keep track of the amount of elefants in the galaxy and then one disappers you know what fell into the black hole. but the problematic part is to work it out in the opposite direction. you know just the state of the universe at the later time (and just at that time, not the history of everything that happened) and you want to find out what it was before. You don't know wether an elefant or a car is missing without knowing the history (or at least one state from an earlier time).

[@ikoukas]

But doesn't that 'debunk' the whole point of this video? If the information of the elephant only comes out after trillions of years when the black hole evaporates doesn't that mean that between the elephant falling inside and the information coming out in the future that information doesn't exist inside the accessible universe?

[@tobiasthrien1]

@@ikoukas Information not being accecssible to one region of space for a period of time isn't the problem (that isn't in contradiction to the laws of quantum mechanics). The information is inside the black hole in that period and the whole construction just shows this explicitly by giving a mechanism for how it is transferred to the outside before the black hole evaporates due to hawking radiation. I guess your argument is that since the information doesn't exist in the accessible universe in the meantime than this is the same as assumming it was destroyed (it doesn't exist at all. who cares if it exists somewhere inaccessable). But that's too simple. If we can geither the information at a later time than it obviously still exists.

[@jazzabighits4473]

@@tobiasthrien1 they didn't really solve anything

[@hayder978]

Excellent explanation!

[@Blessed_V0id]

Tonys cheeky smile and glisten of passion in his eyes fills me with a joy. Like a child discussing the secrets of their favorite game.

[@AlphaFoxDelta]

I love these videos so much. Thank you all.

[@kapa1611]

the analogy confuses things more than it helps... just talk about the radiation dammit xD

[@ab_ab_c]

Exactly. They don't because they can't. They just make up rubbish to pretend wormholes must be the bridge between entangled particles that were never probably disentagled in the 1st place.

[@KlaasDeforche]

I agree

[@CallsignJoNay]

Seriously. Worst analogy ever.

[@CalvinHikes]

I find this almost always true when talking about quantum physics. I generally assume there's not a better way to discuss it with out complicated math. But I like it straightforward without cheap stories attached.

[@jazzabighits4473]

So basically, they didn't solve anything. They came out with a theoretical solution to a paradox and accepted it as scientific fact, even though the fact of the matter (pun not intended) is you can't detect or interpret this apparent information coming through any apparent wormholes (not to mention the physical implications and aberrations of spacetime you'd get if there were worm holes coming out at random angles/tangents to the black hole). This is unfalsifiable, which is akin to pseudoscience. I could've just said "After entering a black hole, the information ends up in another universe, trust me guys, that way our knowledge of entropy/thermodynamics/quantum mechanics isn't wrong!"

[@ButzPunk]

Well now I definitely need an entire video on imaginary time!

[@deandeann1541]

It took me quite some time to understand that i graphically can represent a rotation. I'm unsure about imaginary time as time is constrained to one direction.

[@leoself9858]

Fascinating subject. Agreed with the premise that when we do finally understand black holes it will reveal a higher understanding of the universe too.

[@dustinpace6356]

Congratulations on Liverpool winning professor! Wish all the supporters could have celebrated together. Thanks guys for the videos!

[@locolob0606]

Thanks for this video! The questions and answers were perfect, specifically the segment when asking "what is meant by information". One question: if the wormholes that connect the radiation to the inside of the blackhole are only possible at 1/2 mass or less, does that mean the information paradox still exists before 1/2 the mass is evapourated?

[@Dywindel]

Brady: What do you mean by wormholes? Are they literal holes in space. Me: Oh, they're probably not literal holes in space, that's probably an analogy. Tony: They are literal holes in space Me:

[@adityawirayuthakayasimto8979]

Yeah lol, black hole made me think like that

[@davidwuhrer6704]

It's when two separate points in space-time are somehow the same point. In the space-time diagrams in which space is one dimension and time is the other, they are depicted as holes which connect two separate points in space-time. It's like some volume of space that is both here but also somewhere - and somewhen - else.

[@notarabbit1752]

made by actual worms

[@Hecatonicosachoron]

They are smooth though, they are not like tears or creases of space which are not smooth, and which are not described by any physical theory particularly well.

[@riadhalrabeh3783]

Brilliant and very clear discussions. Many thanks.

[@spaceshipable]

Thanks for asking great questions Brady

[@Groink1]

How do you access the islands inside the black hole after the black hole is fully evaporated and long gone? Are the islands not evaporating?

[@sabarapitame]

You should see the video again

[@Groink1]

@@sabarapitame I did. Didn't help.

[@revenevan11]

@@Groink1 the information was entangled with the radiation. All the radiation is still spreading out into space once the black hole has evaporated, so you get the information from it. (Doesn't matter that it's spreading out through the universe at the speed of light, it still contains the information about what the now long gone black hole was made of!)

[@Groink1]

@@revenevan11 Okay, but the radiation will create entangled states with other particles. Can we then still obtain the information?

[@FPSEli]

It sounds like he's explaining both black holes and the US economic system...

[@thegreyeyedcat9142]

Oof

[@Triggerboy78]

You dont know where the money is gone until most of the government has evaporated?

[@watcherofwatchers]

Not brilliant. Lame and unnecessary in this discussion.

[@avicennam7708]

This is a great video keep it up. Lot of good information

[@mustafa1912]

Wow such a complicated matter and has a fascinating back ground but explained brilliantly and thanks for adding cartoons too they made visualization much easier

[@GeoffreyThornton-TheWinGuru]

Sounds like the makings of a new sci-fi comedy, "Dude, Where's My Elephant?"

[@MantraHerbInchSin]

Dude how could football be more interesting than black holes?

[@yuhmadorwah]

Easily. Have you seen Liverpool play lately?

[@chonchjohnch]

Does the UK have an NFL of its own?

[@markusfarron1644]

I think they're referring to soccer as "football".

[@enderwiggins8248]

This is so fascinating! Hopefully I learn enough physics soon that I can understand the paper myself

[@code4chaosmobile]

Great video and thank you for all your hard work.

[@jazzabighits4473]

1: We always had a problem describing the black hole information paradox, because information seems to be lost and unable to be deciphered or properly retrieved when it passes the event horizon of a black hole. 2: "information" can be thought of as the "state" of a bunch of things, how they are arranged. E.g. if the entire universe was carbon atoms, 1cm apart forever, there is pretty much zero information. Different types of atoms or different positions (different states the universe is in) gives it more information. That is, disorder (or Entropy), can be used to measure information. 3: When something goes into a black hole it seems either information is lost (thereby breaking the laws of thermodynamics which state entropy always increases) or it is damaged to the point where it can't be retrieved (same problem). 4: To solve this, they theorised that quantum worm holes could be "leaking" information out which would account for the apparent loss of information which caused the paradox. (5: Analogy: some people (the universe outside the black hole) give their money (information) to a bank (black hole), the bank holds all the physical money so the people look poor to a 3rd party (other people in the universe outside the black hole), but they are not. If access to the bank's (black hole's) information was available, it'd be obvious to the third party that those people aren't poor. They are saying there IS a way to access the bank's info (access the information in a black hole), but you can't just do it simply through the front door (event horizon), it takes "wormholes" to "leak" the information out. But the point is, the information still exists and is theoretically attainable/understandable.) Really not that hard to explain, I don't even have a university degree and I haven't been to highschool since 2012.

[@gzachar77]

Thanks for the brilliant summary! I have so many questions! What are the consequences of this new theory for a near heath death universe in the far future? Will there be wormholes all around when most of the black holes are almost evaporated? You mentioned, it was gettin easier to make the wormholes as the black hole evaporated more and more. Can they come to existence spontaneously when the hole is almost evaporated? What happens, if the radiation falls into an another black hole? Will there eventually be many black holes interconnected by wormholes? Very small black holes evaporate very quickly (am i right?), are there such black holes in our universe? Can they be tested for signs of wormholes? Also as far as i know, for a wormhole to be kept open some exotic matter is needed which has negative energy. Does the new theory say anything about the nature of such thing? And another thing might be unrelated: if one of the member of an entangled particle pair falls into a black hole, will they still be entangled. Does this not violate the principle of event horizon? Sorry if my questions are naive, my physics knowledge comes mostly form SciAm and your channel :) Thanks again and I hope you keep us updated in many more videos! Greg

[@revenevan11]

I love your idea of many black holes being interconnected by wormholes from their Hawking radiation falling into each other! That's so cool!

[@zapfanzapfan]

Imaginary time is the time I have spent together with Emma Watson.

[@jackofeet1000]

Brady your questions are always so on point. Would have loved a chat between you and Feynman 👍

[@shrimpeye]

Great video Brady, thank you!

[@gigapede]

If information can only be recovered after the black hole has half its mass, then wouldn't that mean half the information is lost?

[@michaelkaliski7651]

Jason Siadek I suspect that what is meant is that once a black hole has lost half its mass, the content of the remaining half can be inferred from what has been radiated already. This assumes two things; first that the information in the black hole is radiated isotropically and secondly that every particle having an exactly equal chance of radiating. So with a hypothetical black hole containing one million and one individual bits of information, as soon as 500,001 bits had been radiated, the content of the remaining 500,000 bits can be calculated.

[@pdgiddie]

I suspect that once you're able to form these wormholes, all the information from the previous radiation can be "unscrambled" and reconstructed. It doesn't really matter that the information was *temporarily* unavailable, since space-time is a single system. So long as everything balances eventually, nothing is lost.

[@ludgrob1]

@@alis8863 this honestly just sounds like a copout to me.

[@jazzabighits4473]

@@alis8863 So basically, they didn't solve anything. They came out with a theoretical solution to a paradox and accepted it as scientific fact, even though the fact of the matter (pun not intended) is you can't detect or interpret this apparent information coming through any apparent wormholes (not to mention the physical implications and aberrations of spacetime you'd get if there were worm holes coming out at random angles/tangents to the black hole). This is unfalsifiable, which is akin to pseudoscience. I could've just said "After entering a black hole, the information ends up in another universe, trust me guys, that way our knowledge of entropy/thermodynamics/quantum mechanics isn't wrong!"

[@Android480]

Would love to know where this theory stands nearing 2022. Is it still considered a real possibility? I remember this episode well, I found it incredibly exciting.

[@yeahnahmate1560]

Nice to hear a theorist holding an experimentalist in such high regard

[@Jehannum2000]

Experiment can disprove theory. Theory can't disprove experiment.

[@ASLUHLUHCE]

Brady asks some great questions

[@krjonovo2063]

Wait what happens when the black hole is radiated away? Can you make these worm holes even after the black hole is radiated away, because if you can't make them after the black hole is gone than that means that information is then lost forever, but if you can that means that these worm holes lead to somewhere but where do they lead if there is no black hole?

[@SmartAlx]

That's the question I wanted Brady to ask.

[@adolfoholguin8169]

Before that happens you can get back most of the info inside

[@SmartAlx]

@@adolfoholguin8169 Most? LOL That's a violation. Also, the information is supposed to remain... FOREVER.

[@adolfoholguin8169]

@@SmartAlx what i meant i that by that point the EFT they used to get the replica wormholes breaks down.

[@SmartAlx]

@@adolfoholguin8169 I don't understand what you're saying. Please rewrite using clear grammar.

[@diGritz1]

So this only occurs after around 1/2 the mass has been radiated away? Doesn't that mean everyone was 1/2 right and half wrong 1/2 of the time?

[@jannikheidemann3805]

How do you count that if two black holes merged?

[@Fish_InChips]

Still don't understand it. I think he explained it in the physicist terms. Interested in the answers to questions like "where are these wormholes," "why can't the particles be entangled without a wormhole," "what is an island and does it represent a physical thing?"

[@Nimbulus85]

The perfect unintentional demonstration of relativity and quantum mechanics. If you watch Tony's shadow during the interview; something about the combined shutter speed of his camera, the bitrate of the video call and the time of day/amount of interference with the photons from the sun outside make it appears as though he's moving at two different rates at once. To the perspective relative to me, his body is in smooth motion. In truth however, his shadow demonstrates it is only a series of photons smashing into my retinas in discrete quanta.

[@paddym6075]

can someone clever answer me this; Hawking radiation occurs when a particle/anti-particle pair appear on the event horizon, and the anti-particle falls into the blackhole and particle on the outside, thus decreasing the mass of the black hole over time. My question is, why don’t events, where the opposite happens (particle forms on the inside of event horizon, anti-particle on the outside), compensate for the Hawking radiation?

[@ktx49]

I just asked a similar question. But also it's even more confusing because anti matter has the same mass/energy.

[@retropulpmonkey]

It doesn't matter which particle leaves. Both particles have mass.

[@tiamagus6641]

They can and do happen the other way around, but due to the abundance of normal matter in space, most anti-particles will collide with a normal one and become a photon in the process. The issue is that absorbing one particle from a pair of virtual particles requires the black hole to give up some energy, thereby making the not absorbed particle 'real', where the energy of the particle is exactly the energy lost from the black hole (there's also the problem of the newly 'real' particle appearing to be the same size as the black hole itself to an observer, but I digress). That's what Hawking radiation is. It's less about whether or not it's an anti-particle, and more about the process by which virtual particles become real. Hopefully that helps. I'm not an astrophysicist, so if somebody notices something wrong with my explanation, feel free to point it out and correct it.

[@juzoli]

Pat _ Because particles created outside can fall into the black hole, but particles created inside can NOT fall out of the black hole. If a particle pair is created inside, both will fall towards the singularity. A particle created outside have more options, they can both fall into, both stay outside, or one falls in, other stays out. This later is the Hawking Radiation.

[@1SmokedTurkey1]

@@juzoli I think you're the only one who understood the question.

[@jacklee5876]

Wonderful interview. Great questions, great answers, really loved the analogies. ^_^

[@jazzabighits4473]

you liked that analogy? lol

[@celewign]

Question: can you actually unpick the fluid cups original state if you have enough computing power, or is the motion of the molecules random in a way that is impossible to backtrack? I had thought Brownian motion was partly determined by quantum randomness.

[@SimonTheWookie]

Hi Brady. First of all I wish to salute you for the accuracy of your questions and the respect with which you treat the professors. it's a fine line. you're a top tier interviewer. This made the hopeless layman in me wonder about preservation of information. Succintly, what about the cosmic event horizon?also as an after-question, since the cosmic event horizon is relative to the observer, this law, dictates that all information must be preserved, then we mean, preserved for the system, right? in a, running time backwards, kind of manner? if we could presume that if we reversed time, an object having disappeared behind the cosmic ecent horizon, might reappear, could we not presume the same of an object having fallen in a gravity well? why does the strength of the gravity well matter so much in the case of black holes, beyond the fact that it's not observable for a period of uhhh god-observer-based time? i don't see how becoming non observable affects its ability to follow a reverse time path to its origin. sorry for the disjointery, i can't English.

[@ekscalybur]

Someone square this for me. A particle and it's anti-particle spring into existence at the event horizon, having never been a part of the black hole. One because of it's location goes into the black hole, so the black hole is now it's entire mass plus this particle, and the other particle that never was part of the black hole flies off into space is counted as the black hole evaporating/becoming less massive.

[@3333amira]

The energy for the particles has to come from somewhere and you can think of the energy as being taken out of the gravitational potential energy of the black hole (which is contained around as well as inside it). The fact that one of the particles escapes means that half the energy from the pair is taken out of the black hole.

[@thedeemon]

Moku's quote is spot on. The popular description with two virtual particles separating is indeed an extreme oversimplification and doesn't make much sense on its own, you're right to notice that black hole would grow in that scenario instead of shrinking. The actual mechanism described in Hawking's papers for physicists (unlike his books for laymen) is quite different. It's about how black hole creation changes the geometry of spacetime such that the basis of quantum fields changes, so the vacuum state of the old basis is not a vacuum state in the new basis, which means it must contain some particles, these are the Hawking radiation. Why that leads to negative flow of energy from the BH is shown with lots of very technical calculations and hard to explain without them.

[@yuotwob3091]

@@thedeemonhaha, all observer's agree, elephant's boot

[@jazzabighits4473]

So basically, they didn't solve anything. They came out with a theoretical solution to a paradox and accepted it as scientific fact, even though the fact of the matter (pun not intended) is you can't detect or interpret this apparent information coming through any apparent wormholes (not to mention the physical implications and aberrations of spacetime you'd get if there were worm holes coming out at random angles/tangents to the black hole). This is unfalsifiable, which is akin to pseudoscience. I could've just said "After entering a black hole, the information ends up in another universe, trust me guys, that way our knowledge of entropy/thermodynamics/quantum mechanics isn't wrong!"

[@masoudbahrami188]

Isn’t it the same as ER=EPR of Lenny Susskind? How is that new and exciting? He figured it out many years ago!

[@Nnda8731]

Correct but it’s been confirmed now and FYI, Maldecena who worked on the proof in the Princeton team also co authored the ER=EPR with Susskind

[@TarikELHAJRI]

I was looking for this comment 👌 Also the holographic principle, that is Key to this "new discovery", was introduced years ago by 't Hooft and Susskind years ago but no mention of their names in the video!!!

[@masoudbahrami188]

Sure, I agree with both but like you said he should acknowledge the inventor of the theory for sure. But maybe he was so excited might forgot. No biggie, just like Lenny so much!

[@bentn1374]

Brady coming out with some really good questions here. As usual.

[@adraedin]

That "Couldn't we do a census of everything outside the blackhole...?" question was a really interesting angle.

[@IragmanI]

How does a blackhole know it's radiated half it's mass before these wormholes develop?

[@anastasiosmertzanis4818]

It doesnt know it. Gravitational forces just become low enough for warmholes to start forming

[@CallsignJoNay]

@@anastasiosmertzanis4818 That makes no sense. Half of what? Let's say you have two black holes. Black hole A has a mass of 2,000 suns, and black hole B has a mass of 1,000 suns. They both radiate away half their mass. Black hole A is still twice as massive as black hole B, but now they are both magically able to form worm holes where as before they couldn't? How can that be true if black hole A is the same size as black hole B before it radiated away half its mass?

[@jazzabighits4473]

@@anastasiosmertzanis4818 So basically, they didn't solve anything. They came out with a theoretical solution to a paradox and accepted it as scientific fact, even though the fact of the matter (pun not intended) is you can't detect or interpret this apparent information coming through any apparent wormholes (not to mention the physical implications and aberrations of spacetime you'd get if there were worm holes coming out at random angles/tangents to the black hole). This is unfalsifiable, which is akin to pseudoscience. I could've just said "After entering a black hole, the information ends up in another universe, trust me guys, that way our knowledge of entropy/thermodynamics/quantum mechanics isn't wrong!"

[@acetate909]

You lost me at the lavish party but I found you again through the wormhole.

[@BillMSmith]

Great video as always. Stereo Tony at 15:15 is superb.

[@Ideasquevalelapenadifundir]

Thanks a lot for this video!

[@Sublimeoo]

I think you need to get him back to explain imaginary time xD

[@alan2here]

I agree :) p.s. My comment is still here?

[@MichaelEhling]

@@alan2here nah Mate, it fell in. You have to wait for a bit. Then you'll see it pop out of the wormholes.

[@bentaye]

3:45 I though that sentence was karl pilkington for a second.

[@chubbyadler3276]

Something I've been wondering, seeing that the deeper we go into quantum mechanics, the more we find to dig through, is that perhaps the frame of reference itself could be the "source" of the lost information itself. Perhaps as the nanoparticles at the smallest scale, whatever that happens to be still undiscovered, enter the black hole and are randomized, in the same way as matter falls into certain stars and the atoms themselves break apart, forming neutron stars, quark stars, etc., nothing about those nanoparticles are changed except for their bonds to each other. As a result, there is no information lost, though the larger scale effects, being charge, mass, energy, etc., become accessible similar to how a video in edit may be lost due to the randomization of magnetic poles on a hard disk. You still have the same mass and volume of magnetic material in the same locations, but since the poles are now all over the place and not in an order, the "information" of the video in question is now missing. (Always keep backups, by the way.) The same thing is likely happening with a black hole, and as it evaporates, these nanoparticles are being liberated somehow.

[@alexpearson8481]

I love the comments here in these science videos. Intelligent, thoughtful comments.

[@_jb_3441]

Hmm..I don't know. It's either really complicated or he is just explaining it wrong but like this the explanation sounds really cheap to me.

[@dariusherick7001]

When the half black hole has to be vaporized can you get the Information from that half too🤔

[@ticketforlife2103]

no

[@TranceFur]

So that information is lost. I don’t see how they’ve really solved the paradox.

[@patrickgreen1656]

The information is clearly there before the black hole forms. Then I guess this new theory shows that at the end of the black hole's life the information is still all there. So we can infer the information was never deleted only spread between the inside and the outside. No-one said information can't move around (I.e go in and out of the hole) just that it shouldn't be deleted at any point.

[@patrickgreen1656]

Yes, you can get it by just waiting and measuring everything that comes out as the second half evaporates

[@jazzabighits4473]

@@patrickgreen1656 I think you're wrong because if information gets put into a black hole and scrambled into random information, that isn't deleting it, it's just damaging the information you can get from the matter.

[@MD-kl1tr]

When something hits a black hole, it gradually increases its mass, thereby changing the black hole's gravity, gravity changing at the speed of light, and you can definitely tell how massive the particles added at a certain point in time. Gravity is the only thing that can carry information out of a black hole.

[@sykes5000]

My favourite channel on youtube

[@discreet_boson]

Me when I see that 60 symbols has uploaded: A surprise, to be sure, but a welcome one

[@lutz18692]

That bit about Emma Watson was so weird like wtf are you talking about Tony haha

[@samcottle]

I agree with Tony on that last point about quantum gravity. The more I've looked into this myself the more I've come to suspect that most, if not all the major theories of quantum gravity, might turn out to be "not even wrong". As for my thoughts on Hawking radiation, I think tunneling electrons from the black hole interior deposit photons beyond the black hole's event horizon, and that these electrons would also be comprising the gravitational field of the black hole, hence acting as a sort of quantum for gravity. But that's just my own crazy theory.

[@vee.m]

I quite like these kind of videos

[@AliHSyed]

"imaginary" is a criminal misnomer... Makes it sound like it's not real. But complex numbers are just as real as our regular number line.

[@inertia9325]

Hmm. I can demonstrate physically what “one” (or any other real whole number) object is. I can demonstrate zero by having no objects. I can demonstrate fractions by having partial objects, like, say, half an apple. I can demonstrate irrational numbers just by drawing a circle. I can even demonstrate negative numbers physically by interpreting them as removal of objects. There’s no physical way of demonstrating sqrt(-1) objects, however. That's why I always argue that imaginary numbers aren’t just as real as the reals. That doesn't change the fact that they're incredibly useful in many ways, though.

[@ModusTrollens91]

​@@inertia9325 You demonstrate imaginary numbers by looking at any cyclical process. Or the fact that quantum wave forms are an imaginary function. Seems embedded in reality to me.

[@psbbianforlife]

complex numbers are made of two parts. a real part and an imaginary part

[@Djorgal]

​@@inertia9325 No you can't show physically what "one" is by showing an object, what you've shown is an object, not the concept of "one". What you did is a model, you mapped this concept onto reality. A model is not the thing itself. There are many such models that works for complex numbers. For example, I can show the very physical thing of a 90° rotation to the left and tell you that this is the number i. That's correct, a quarter turn counterclockwise is the number i, or at least it models it just as much as "one" models the presence of a single object. There are also many other things that complex numbers can model, and the same is true for integers. In some sense they are even more real than the real numbers because if you only allow yourself to consider real numbers, you lack numbers. It is just like if someone told you that they use integers but not 4. They don't like that one, thus they refuse to consider it. Then there would be something lacking in the way they count. The same is true if you only consider numbers that have no imaginary component, you are lacking something and you can't really count correctly.

[@whywatchme2214]

Djorgal nope 👎🏽

[@ShipOfFreaks]

"imaginary time" lmao

[@a51mj12]

At last, some very good content!

[@robnorris4770]

My life since lockdown has been in imaginary time.

[@pixartist8190]

Just saying, there's a lot of people on yt that can handle a bit more technical depth. PBS spacetime proves that. I wish you guys wouldn't feel the need to package everything in analogies and instead go wild with the explanation

[@FarnhamJ07]

Right? The analogy with the paintings in this video seemed particularly ridiculous. To me, the base idea that "information still exists in these 'islands' and is accessible via wormholes" seemed pretty straightforward on its own, and he doesn't explain much beyond that. Such a contrived analogy didn't help with intuition or whatever at all!

[@apadila1975]

To be fair, we only used the one analogy and it wasn’t ours - it was from the recent review of this work by Maldacena et al and the east coast architects. So we were recounting that story which is part of the narrative. What we must understand is that a simple intuitive explanation simply doesn’t exist - if it did it wouldn’t have taken 45 years to solve (it indeed it is solved). So we just tried to give a flavour of it. You cannot do more with assuming certain knowledge (eg what is a mixed state vs a pure state - a video in itself; semi classical methods in Euclidean quantum gravity - a graduate lecture course in itself; etc etc).

[@nejnovejsi]

I have question. Does this mean, that each black hole develops these wormholes "on its own" and all the information always must leak out before the black hole disappears? Or does this have to be prompted by some kind of measurement or sth?

[@TheShanks]

I'm always impressed with bradys questions.

[@MarkoKraguljac]

They think their "cashless art collector" scenario is imaginary but thats how our plantation "economy" works.

[@bustedrav]

This sounds like more of an idea than a breakthrough. I'd like to see the math, wait, no I don't....

[@dandan7884]

the way he talks about the diffilculty in extracting information from a blackhole reminds me of how one would proceed to reverse engineer the md5 algorithm, for example. after you send your password (information) to the md5 algorithm (blackhole) it will become a seemingly random hash (radiation). if you want to work your way back from the hash (radiation) to the password, you would be dealing with probabilities of states and in the end you could have many other different passwords (information) that matches the same md5 hash you began with. as if the same atoms that make up an elephant could be rearrange to become a car

[@UnforsakenXII]

Penington has literally just been hired by the Berkeley department. Super super super excited to meet him. = )

[@voodoojedizin4353]

To make a long story short he is saying we need more grant money so let's make something up.

[@bobfish7699]

So am I the only one who didn't understand the explanation at all? I found the analogy even more non-sensicle

[@thenasadude6878]

In practice, even if you don't have access to the information inside the black hole, hawking radiation can be analyzed. This analysis will reveal information about what went into the black hole, because the radiation particle has access to what's inside via the wormhole. The mind blowing fact is that the radiation particle never went inside the black hole, but carries information regarding it anyway

[@jazzabighits4473]

So basically, they didn't solve anything. They came out with a theoretical solution to a paradox and accepted it as scientific fact, even though the fact of the matter (pun not intended) is you can't detect or interpret this apparent information coming through any apparent wormholes (not to mention the physical implications and aberrations of spacetime you'd get if there were worm holes coming out at random angles/tangents to the black hole). This is unfalsifiable, which is akin to pseudoscience. I could've just said "After entering a black hole, the information ends up in another universe, trust me guys, that way our knowledge of entropy/thermodynamics/quantum mechanics isn't wrong!"

[@ashutoshchakravarty2669]

Brilliant questions

[@danielleriley2796]

I was thinking exactly what the interviewer asked. My pet elephant is gone but my car isn’t. Great interviewer.

[@ondrejmarek1980]

i need Sabine Hossenfelder take on this

[@jansenart0]

10:00 That's the absolute worst analogy I've ever heard. What I need to know is what principles exactly of QM that are violated by matter being torn down into photons by gravity.

[@thenasadude6878]

Gravity is not a force field, I don't think it can transform one particle into another. It is ignored in QM.

[@apadila1975]

It wasn’t our analogy. It was from the recent review by Maldacena and East Coast team. Sorry that you didn’t like it. I honestly don’t see how any other channel could make this very advanced topic more accessible whilst sticking to the facts. Remember, it took 45 years to solve

[@DubStepNMany]

omg the knot in brady's headphones... 13:38 :o

[@CleberCFros]

Teoricamente a informação pode ser criada em outra forma que ainda não conhecemos, uma configuração diferente . Quanto webhole, o magnetismo poderia criar esse túnel?

[@Yutani_Crayven]

You can throw a car or an elephant into any random star and won't be able to tell which it was after the fact, either. These examples are horrible.

[@AnexoRialto]

You could imagine studying the star and every single particle and it's movements within the star and reconstruct whether it was an elephant or car. The point is that the same is not true of a black hole because you can't directly access the black hole to carry out the reconstruction.

[@jazzabighits4473]

@@AnexoRialto No you couldn't do that because the amount of material an elephant or car has compared to a star is negligible. It'd be like figuring out there was once something the size of human being or smaller on a planet the size of earth through studying the geological record.