I could listen to Sean Carroll all day, every day. He seems to perfectly blend the mind-boggling complexity of his subject matter, with an ease and flow of delivery that makes it come across as comprehensively understandable at an engaging and relatable level.
This means so much to me.. I am a student from India with just no resources at all.. This empowers me.. Thank you everyone who is involved in this channel and video
Think of it as an apology from the Royals of England to your and any other country who had to endure their reign earlier in history. Also, you have the internet, the most powerful tool in history for learning, if you want it to be. Good to see that you have an interest in the basic fundamentals of everything, it's an extremely good character trait in my eyes. Schooling does count for something, but the basic human trait of curiosity is so much more important.
I am from India, but I have the resources! How is it that you don't? All we need in today's world is a laptop with internet connection and am sure u have that.
check out Leonard Susskind's lectures from Stanford. You, like the rest of us, have access to the best lecturers I the world. This is a wonderful age. Take advantage of it!
It happened first time in my Life that I watched a UA-cam video of one and a half an hour without skipping even a single second. Sean is a great explainer.
I traveled for nearly a week from an MSF mission in the Congo to attend these two's wedding in LA in the 2007 (ish?). Unique, beautiful ceremony. Took another nearly a week to travel back.
WTF at times it was a utterly incomprehensible USELESS explanation & nobody knew WTF he was talking about eg: 47:47 _"In a black hole, the 2-dimensional event horizon really does contain all the information you need, to talk about what's happening inside, according to the holographic principle. But it should be true even in this room, or the galaxy or the universe. & if that is true, locality is being dramatically violated, because there is a lot less that can possibly happen in this room than you thought could. You thought that something could be happening here & something could be happening there & different things could be happening at every point. But the holographic principle says: No, that's not true. 1 of the arguments for it, is if you imagine all of the different possible things that could happen most of them would have a lot of energy & would collapse to make a black hole. So there is an upper limit on the number of things that could happen in this room, & the size of the upper limit is proportional to the area of the walls around this room. So there is this hypothesis that all of physics really lives in a world that is 1 dimension lower than the world we actually see. & again, we are trying to make sense of this idea. We are making progress, but we are not completely there yet."_ _"The other idea that has come out of Black holes and argues against locality is called Black hole complementarity. Remember I said that, from the point of view of Bob from far away, he sees radiation coming out of the Black hole, and he says: well if I trace it backwards, it must have been very high energy radiation when it left the event horizon. Whereas Alice, in the conventional way of thinking about things, passes through the event horizon & sees nothing there, just empty space. So they had incompatible ways of describing the same situation. Bob thinks the event horizon is bubbling with high-energy radiation; Alice says there's nothing there. Black hole complementarity says: they are both correct. Black hole complementarity says they are different-sounding ways of giving equivalent descriptions of the same fundamental underlying reality, & that 2 things that are seen by 2 observers can look very very different, as long as the observers can never get together to compare notes. So what happens is, if you give Bob enough time to collect the Hawking radiation, & figure out what he thinks the horizon looks like, & you give Alice enough time to fall into the horizon. If Bob then says: alright, I've got some data; I know what's coming out of the Black hole. I am going to fly into the Black hole & tell Alice what I saw. It is too late. She has been spaghettified & crushed into the singularity. So these 2 observers see a very different thing happening in the world, but hey can never talk about it. Only we - God-like physicists, looking at the whole thing from afar, can give the bird's eye view on everything that is going on. That is the principle of Black hole complementarity. It's borrowed from the early days of quantum mechanics when Niels Bohr pointed out that you are allowed to measure position, OR you are allowed to measure velocity. You are not allowed to measure both at the same time. That was quantum complementarity; this is Black hole complementarity. So again, it's a violation of locality in some sense. It says that the right way to describe the world isn't what's happening here, & what's happening there, & what's happening there, and what's happening there, separately. What's happening right there can depend in a very dramatic way on who's looking at it & from what perspective. So somehow, all the information about what's going on in the world is not simply located in individual points in space. It's encoded in some cryptic way that we don't yet understand, & that's what we are trying to get at, by doing these thought experiments. The problem is, these 2 types of non-locality, don't seem to be enough to solve the firewall puzzle."_
I could listen to you all day, Sean. Thank you for all your talks. I get them off youtube. I watch many academic lectures in physics to better grasp these concepts of the nature of black holes & the reality of space-time. I only have a BA in music, but I do understand acoustic physics. So, I do have some foundation; just not a very strong one. I can't help but be excited about this stuff. It's what I do for entertainment, instead of TV & that nonsense. Thank you for your contribution to humanity, Mr Carroll
+CaptianKeyz Imagine where we could be as a species, if more people thought of this as entertainment instead of the absolute dreck populating TV, cinema, and radio, encouraging our children to follow in the footsteps of the great thinkers.
Sean is likely my favorite of his peers in terms of public communication; I enjoy his zeal and humor. Thanks for your time and thanks for uploading this!
@@percestyler Sean Carroll doesn't believe in the scientific method?? That nonsense you wrote plus the typical name calling reveals it is in fact you who doesn't like him just because he's an atheist. Everything he's said here is valid regardless of the existence of God.
Same. I have the need to watch Sean Carroll lectures while doing something slightly less complicated than quantum mechanics, namely lace knitting. 🤣 Weirdly, it keeps me on task!?
First, I would like to say that having these kinds of lectures available on the internet is something that fills me with such a sense of pride in the human race that is refreshing. Thank you so much for this gift. Second, I would like to point out a small correction. In the talk, Sean Carrol states the unfortunate link between the term "firewall" in this context and in computer science. Well, actually, the analogy is EXACTLY what happens in a computer firewall, except with a twist. The way a firewall works is it's a "membrane" any information wanting to pass from one network to another as to go through. The default behavior is that any information is stopped. How is information stopped? It is "destroyed". This is the membrane acting "as nature intended". Destroying information is something we do all the time in computer science. How do we do it? We make heat. That's one of the reasons why your computer gets warm. The twist is the trick to computer science. We get to cheat and decide what information is allowed to pass, basically by deciding to look at it instead of dissipating it. That's what makes it a very useful thing to protect "my precious universe" from the big bad things on the other side of the firewall.
Not to be pedantic, but... Actually the packets that DO get through generate more heat than the rejected packets. All packets are equal before inspection. Dropped packets simply cease to be, but allowed packets have to be reassembled and forwarded to their destination, which requires more energy to transmit on down the line as either electricity or light.
LOL i just explained that firewalls have been around for some time (before computers)... if i remember right the first recorded instance was after londons great fire... adjacent buildings had to share at least one wall of stone, brick, or other masonry.
This is amazing lecture! I stumbled upon this channel by accident but the skill, clarity and fervour of Mrs Ouellette had me anchor here and bask in the faint. warm glow of all the rest of the videos on the channel. Thank you! Subscribed with a rare and true joy.
Exceptional talk! Thank you to Ri for sharing this. A huge thank you to Jennifer Ouellette and Sean Carroll for sharing their thoughts and research with us.
Came to understand more about black holes, only to now understand we know seemingly less about black holes than we assumed in the past...I LOVE SCIENCE :D
Wonderful talk! The way Sean can convey such complex ideas in a nutshell with such clarity to the layman without missing a beat is an incredible skill. I think Feynman could do this too. Thank you for making these videos.
My biggest dream at the age of 33 and just beginning to start my physics education is to contribute beyond the giants shoulders I've stood on for a year now. I have ADHD and the only thing I can keep focus on is absolutely everything to do with physics, mathematics, general relativity, quantum mechanics, and etc. It is a privilege to be able to learn so much for free these days. Godspeed.
Nice talk but I also really enjoyed the question and answer period, could have enjoyed an entire vid of just that, he's good at answering questions cold off the cuff, and people in the audience are good at trying to narrow down ambiguities in language from the main talk to pierce the veil of the analogies a little bit while simultaneously sean immediately understands what they are getting at and resolves the ambiguity to clarify what is really being said.
The guy asking the question at about 1:17:00 ish, I like to think about it like this: Get a piece of elastic, and mark it close to the left end. Grab the elastic by either end and stretch it. The rate at which the mark moves away from your left hand is remarkably less that the rate at which your right hand is moving away from your left hand. Nevertheless, the elastic is stretching uniformly.
I've read Jennifer's articles on Ars Technica for years, but this is the first time I've seen her on video. Crazy. Wonderful presentation, btw, and love her works on Ars.
I have watched this, maybe, 27 times, and I still find something subtle I didn't catch before! I would love to have dinner conversation with these two!
Wonderful lecture by both Sean and Jennifer. I've been a professor of psychology for 43 years and during the last 6 years I have become fascinated with quantum mechanics and cosmology. I would like a do over in life as a theoretical physicist. Unfortunately, that can't happen.
Perhaps all was not lost, as in another universe you did become a theoretical physicist! Although i bet in that universe you wish you had become a professor of psychology.
I'm 63 with a high school education who got D's in any math class I managed not to flunk and I intend to spend the rest of my days trying to understand this stuff! Enjoy physics on your free time!
I don't think the average person can understand the higgs mechanism. At university they don't even bother teaching it to undergrad students. I never understood any of this stuff until I started writting out the math and playing around with the numbers: Put in 0 or 1 and see what answers you get. It took e yaers to figure out how a massless particle can push" a massive particle but it can due to compton scattering. Once you do the math it makes sense.
It's true that some people are very logical without having a particular interest in mathematics. However, if you are interested in mathematics, e.i. are good at it, you very likely are logical. But, yes, Philosophers are very logical and great thinkers but aren't necessarily good mathematicians.
@@daveb5041 There are different levels of understanding. I can follow most public lectures about GR, black holes and quantum physics without a lot of difficulties, but there's no way I could do the math, and I'm well aware that public lectures are a very downsized version of what a physics student would have to learn. So it's like being around a black hole: From the perspective of an average citizen, I'm quite savvy in astrophysics and quantum theory, but from the perspective of a physics professor, I'm not even a noob. And, as we have learnt, both are right ;)
Am I the only one that feels like I can remix music under her speach? This is a conpliment, it's almost rap without the background music. Plus what she's actualy saying.... Art man.
You can avoid spaghettification falling into a black hole by rotating at high speed. So remember, if you feel yourself going, tuck and roll, tuck and roll.
I'll just measure the size of this black hole as I'm falling into it.....What? If you're going to die anyway, there is no down side. Tuck and roll, tuck and roll.
Must say again, how lucky we are to have Professor Carroll talk. Gifted, certainly. Additionally, my cat's name is Schroedinger; she's very much alive, and wants you to know that, other than for recreation, has never been in a box, and if she chooses to nap in one, please do not bother her to check her "state."
Sean: "You've come very close to inventing what is called the Many Worlds Interpretation of Quantum Mechanics.." Audience Member: "Oh, thank you very much. I have to text my mum, she'll be very proud!" LOL.
The first time I conceptually understood Hawking Radiation and my mind is blown! The black hole rips virtual particles apart and it creates 2 real particles, 1 goes inside the black hole and the other goes outside, the one outside has positive energy and the one inside has negative energy, which is why it loses mass. And I just took for granted that the black hole would lose energy.... I thought it would just get tired, not realizing that it if it's truly black it wouldn't lose energy.
@@alexlarsen6413 I thought I heard Sean say between 32 and 35 minutes that the charge of the two particles is opposite, the spin is opposite and also the energy is opposite. So the particles falling in have negative energy. I don't think enough time was spent on this oddity.Does that mean the firewall is comprised of negative energy? And how do particles with negative energy behave? And what happens when they interact with particles with positive energy? And can particles have negative energy inside a black hole but not outside? There are a lot of questions which were not dealt with in this talk.
You know I really appreciate someone who stops to take a moment and pause to reflect on the fact they're standing at the very desk where Michael Faraday once stood. Truly standing on the shoulders of a giant
46:38 is it not the case that volume and outside surface area would necessarily increase proportionally? Not sure I understand why the distinction about increasing entropy being dependent on the (2D) area of the event horizon as opposed to the volume of its interior is so important. Could anyone clarify?
This is called the “no drama” principal, but Bob is just asking for it, trying to entangle with Carrie, when he knows Alice is waiting at the end of time for him.
So, the first audience question is exactly what I wondered since ever, and I have the feeling Sam's answer is not addressing the problem. He says that Bob cannot see Alice anymore at some point and therefore Bob cannot exclude that Alice has not passed the horizon. But, we do not need visual evidence to know this. The equations of GR tell us that time dilation becomes infinite from the perspective of an outside observer, and so we can conclude that Alice never passes the horizon (from Bob's point of view). In fact, Bob can conclude (by calculation) that the BH must evaporate before Alice falls through the horizon. And this is the point that he does not address. He always shift to "but Alice sees ..." and "Alice' point of view is relevant". But this is completely irrelevant to the question. The question is what an outside observer must conclude about the fate of Alice.
I'm no expert, but maybe the answer has to do with the uncertainty surrounding quantum mechanics. That the amount of time it takes for the black hole to evaporate can be calculated, but this is only an average, and it could be much quicker or much slower depending on the roll of the dice. Crucially that there is an infinitesimal probability that it will take an infinite amount of time to evaporate. Therefore you can never say categorically that the black hole has evaporated before Alice has fallen in. Secondly that the photons reflected from Alice as she falls in will rapidly become very dim and infrequent - and perhaps these become merged with those emitted by the hawking radiation? Maybe if you shine more light on Alice as she falls in, this will allow you to see her better, but this also adds mass to the black hole, delaying the time of occurrence of evaporation.
Could the near infinite mass inside the event horizon disrupt particle interactions with the Higgs field, making them massless and allowing them to escape as Hawking radiation? Once outside the event horizon they start interacting to regain mass, giving the impression the black hole is losing mass, and the mass acquired by the black hole is compression of the Higgs field? Arttu Rajantie, a theoretical physicist at Imperial College London, revealed that when space-time is greatly curved, the Higgs boson increases in mass. Could black holes be made up of Higgs boson's and everything else escapes as Hawking radiation?
Well, I'm not actually a physicist, only an enthusiast. Maybe that's the reason I haven't quite understood the contradiction between the Hawking's radiation principle with the integrity of information. I mean, why is there a contradiction? Why information was considered lost by Hawking if the same information that falls into the black hole would eventually evaporated out from it as radiation?
Oners82 Well. Since I've posted this comment/question I've been studying and reading about these black holes paradoxes. I realized that actually the black hole evaporates not because it irradiates the matter that falls into ir, but because there is anti particles created from the virtual particles separation that happens at the event horizon. So what comes out of it actually comes out of the event horizon and not from inside. If I am right, that answer my question. So in fact, what is coming out of the black hole is not actually coming from inside. It's just the positive particle from the virtual particle that was created at the event horizon. Actually no information is coming out it, and that information that falls into like dust, meteors, etc., is being neutralized by antimatter created at the event horizon. So in fact, by this point of view information would really be lost.
Oners82 If the pair production is the process by which they evaporate, technically the information that comes out is not coming from the black hole. So how can he evaporate if not by the annihilation of matter inside it? I mean, the radiation that is coming out comes from the event horizon, not from inside, right?
Oners82 I suppose there are two events regarding information falling into the black hole. First is the negative pair particles created at the event horizon which negative ones fall into. Second one is about the matter that comes from the space such as meteors, dust, stars and so on. These seems to me quite different events. If you consider the quantum entanglement principle to be preserved and use black hole complementarity to solve it, that would be OK with particles that are entangled. But a meteor is not entangled, is it?
Oners82 Well, I understood. Actually I kinda understood the whole point of my question (which was my idea that information would be lost through the contact with negative particles into the BH) on your first answer when you said that when positive and negative matter collide they release energy, so it enlightened my mind on how my thoughts about the hole process was wrong. Thanks for your consideration. I really am. Sorry for my dumbness :-) I'm sorry. I haven't made my self clear. This would be a second question. Actually this comparison I've made before, which may seem really stupid, in my mind has some sort of a sense. I've made this comparison because along Sean's lecture he talked about how it would feels like for someone to fall into a black hole. First he says that according to no drama principle (classical thought), a person would feel nothing at the no return point (event horizon). After this, he speaks about the Firewall concept, that Alice would be shred to pieces right at the event horizon. After that he proposes complementarity principle as a solution to this deadlock. Basically, the whole point of my comparison is that, his subject is considering entangled particles that would never talk to each other in such event. But what if we are talking about a non entangled particle falling. Would complementarity apply to that scenario? I mean, there wouldn't be a particle to "not talk to". Wouldn't it mess complementarity? It seems to me that complementarity, when it concerns whether a particle is shred to pieces or if it would feels nothing at the event horizon, only solves the cases with entangled particles.
I do have a question to Sean. The black hole tears the empty space, alice pop into the singularity while bob go away. 1. As nothing escapes from the black hole how could bob manage to do it. 2. After the empty space get torn down, what possibly could left behind on there. Thank you.
P.P.S. At 1:03:00 he is talking about the gravitational redshift of light/radio signal from Alice to Bob. But that's not at all important in this context. What is important is what HAPPENS from a certain observer's point of view. And that can always be deconvolved from light (or radio etc.) signals sent out from both parties (Bob & Alice). And on that matter, I'd be delighted to hear the opinion of these experts here.
Frankly, I don't understand the statement at 35:18. (And ok, that might be only my problem.) Two entangled particles that are either "red" or "blue" when observed, represent exactly 1 bit of information, not 2 bits. That 1 bit is preserved in Bob. Alice is not needed outside the event horizon to carry that information, she is redundant. (Sorry, Alice.) So why would we need Carrie? Does Bob somehow "know" that he once was entangled with a particle that is now lost? Is being entangled a measurable property of one particle? I thought it's not. I'm sure there's a reason and the talk is correct. I just don't feel it is explained here--and it seems crucial for understanding.
Quantum Woo are the metaphores that are used to make people understand QM a bit more. Unfortunately, those metaphores are never 100% accurate. Even I am guilty of this for parts of QM.
I don't understand how information is lost in the black hole in terms of virtual particles. If the particle that goes in is entangled with the particle that escapes, don't the properties of the escaping particle that are measured give us the exact information of the particle that doesn't escape(as the entanglement causes those properties to be opposite to the ones measured). Plus surely if they come from empty space, isn't the 'total' information content 0? And for objects falling in, how would that information become encoded in the virtual particles( hawking radiation)? Thanks for the clarification!
This video, inspiring the deepest thoughts mankind can imagine - 100k views. Nicki Minaj, Gangdam Style, and Pewdiepie - billions of views. This is harder to conceive of than any topic in this video. Henry Rollins said it best...disgusting, disgusting on an epic scale.
I wouldn't call it disgusting, I would call it natural. Evolution, even cultural evolution, is very gradual. You can't fault people for behaving like the primates that they evolved from.
Guess most of the people are scared off for life from physics (or science in general) in high school. Remember your physics classes? They didn't have much in common with lectures like this, did they? Plus, most of the times they didn't even cover interesting stuff. I think science teachers could learn a lot from UA-cam.
it has Taken this Man Quite some time and Many Explanations to Say that Somewhere in this Universe and Possibly somewhere outside this Universe he is Both Correct and Wrong...LOL
Thank you both, a question I'd like to put forward begins with a photons red shift. Matter isn't expanding but lights wave length is, could light also suffer a loss of energy in this process to contribute to Dark Energy. Apologies if this is ignorant, again thank you both for the discussion.
Jennifer Onellette should avoid self deprication, and right from the start: "I'm not worthy." (Nervous laugh...) Of course, you are worthy! The producers of this presentation should consider different microphones. Headsets are distracting.
Peter Wexler it's like giving some kids a short basketball lesson, only there's another big one by Michael Jordan after you, it's safe to have some self deprecation here,
Oners82 "I think you are probably the only person who gives a shit, let alone even noticed the headsets." Anyone who's got at least an undergrad degree in Speech Communication will notice, and half of those will "give a shit."
I have a question: HOW CAN YOU PRESUME THAT BOB COULD BE ENTANGLED WITH CARRIE?! First of all, I would like to mention that I sucked HARDCORE at maths, physics & chemistry in school, so I apologise if my question is dumb Here it goes Time reference in video: min 35:16 OK SO I GOT THIS PART: 1)Bob is entangled w Alice 2)Alice gets sucked into black hole => Alice has - energy => Bob has +energy 3)Bob is then entangled with Carrie that used to be entangled with Dave that was also sucked into black hole WAIT WHAT?! If Dave is in b hole => Dave is -energy => Carrie is +energy SO HOW CAN YOU PRESUME THAT BOB COULD BE ENTANGLED WITH CARRIE IF THEY'RE BOTH +ENERGY? Is it not a necessity for entangled particles to be of opposite energies?
Two questions come to mind. 1. As a virtual pair is crated on the edge of the event horizon. Why is it always the positive energy particle that escapes and the negative particle that falls in the hole? 2. When is the information actually lost? If one particle leaves and the other one falls in the hole and they are both entangled. Would we not know the state of the one in the hole by measuring the one that escaped.
I don't quite understand why in QM it is a problem, when particles or information goes into a black hole and just stucks there. Does this mean the information is destroyed? Couldn't it be that it is just out of reach for us? And why it is a problem when information gets destroyed anyway? Is there a link to a document or a video which explains this well and in detail?
The only one who proposed a real new way of thinking about all this are Susskind and T. Hooft. Carrol is a good explainer for the masses, but he is no discoverer.
In many discussions about black holes, there seems to be an assumption that the event horizon is a clear boarder that being the same to all observers. However this seems to be self contracting since by definition the "maximum" event horizon is the border where inside it light can't escape to infinity. However if you are closer to that horizon (but not entering it), the light inside that border can still reach you since you are not infinitely far away. However there should still be another horizon relative to your position so the light inside it can't reach you. This horizon should be inside the "maximum" horizon, and the Hawking radiation temperature should be higher than what was observed from infinity. Therefore, if getting closer and closer to the black hole the temperature should become hotter and hotter but you will never be able to "touch" the horizon until it becomes so hot that it destroys you. Is there anything wrong in the above thought experiment?
I don't understand how you can have entangled particles where one particle can have positive energy and the other entangled particle has negative energy. How can a particle have negative energy? How can anything have less than zero energy? Sean said if you initially have two virtual particles just outside the event horizon that they are "ripped apart" as they reach the event horizon. In the process they are transformed into two real particles, one having positive energy (Hawking radiation) ejected outward from the event horizon and one having negative energy falling into the black hole and into the singularity. I understand the concept of conservation of energy from thermodynamics. Is it the case that the inward falling particle has a negative energy relative to the outward ejected particle's energy or that it has a negative energy relative to absolute 0 K or relative to the energy level of the surrounding vacuum space? If anyone could help me understand this it would be greatly appreciated.
Anti matter has negative energy to allow for annihilation to occur. look into particle physics for more detail. I believe feynman does a good lecture on it
No it isn't. A lot of this video is incomprehensible. DrPhysicsA did the best video on BH. E.g. Carroll said this gooblegook: 47:47 _"In a black hole, the 2-dimensional event horizon really does contain all the information you need, to talk about what's happening inside, according to the holographic principle. But it should be true even in this room, or the galaxy or the universe. & if that is true, locality is being dramatically violated, because there is a lot less that can possibly happen in this room than you thought could. You thought that something could be happening here & something could be happening there & different things could be happening at every point. But the holographic principle says: No, that's not true. 1 of the arguments for it, is if you imagine all of the different possible things that could happen most of them would have a lot of energy & would collapse to make a black hole. So there is an upper limit on the number of things that could happen in this room, & the size of the upper limit is proportional to the area of the walls around this room. So there is this hypothesis that all of physics really lives in a world that is 1 dimension lower than the world we actually see. & again, we are trying to make sense of this idea. We are making progress, but we are not completely there yet."_ _"The other idea that has come out of Black holes and argues against locality is called Black hole complementarity. Remember I said that, from the point of view of Bob from far away, he sees radiation coming out of the Black hole, and he says: well if I trace it backwards, it must have been very high energy radiation when it left the event horizon. Whereas Alice, in the conventional way of thinking about things, passes through the event horizon & sees nothing there, just empty space. So they had incompatible ways of describing the same situation. Bob thinks the event horizon is bubbling with high-energy radiation; Alice says there's nothing there. Black hole complementarity says: they are both correct. Black hole complementarity says they are different-sounding ways of giving equivalent descriptions of the same fundamental underlying reality, & that 2 things that are seen by 2 observers can look very very different, as long as the observers can never get together to compare notes. So what happens is, if you give Bob enough time to collect the Hawking radiation, & figure out what he thinks the horizon looks like, & you give Alice enough time to fall into the horizon. If Bob then says: alright, I've got some data; I know what's coming out of the Black hole. I am going to fly into the Black hole & tell Alice what I saw. It is too late. She has been spaghettified & crushed into the singularity. So these 2 observers see a very different thing happening in the world, but hey can never talk about it. Only we - God-like physicists, looking at the whole thing from afar, can give the bird's eye view on everything that is going on. That is the principle of Black hole complementarity. It's borrowed from the early days of quantum mechanics when Niels Bohr pointed out that you are allowed to measure position, OR you are allowed to measure velocity. You are not allowed to measure both at the same time. That was quantum complementarity; this is Black hole complementarity. So again, it's a violation of locality in some sense. It says that the right way to describe the world isn't what's happening here, & what's happening there, & what's happening there, and what's happening there, separately. What's happening right there can depend in a very dramatic way on who's looking at it & from what perspective. So somehow, all the information about what's going on in the world is not simply located in individual points in space. It's encoded in some cryptic way that we don't yet understand, & that's what we are trying to get at, by doing these thought experiments. The problem is, these 2 types of non-locality, don't seem to be enough to solve the firewall puzzle."_
Does anyone know what the current state of the firewall hypothesis is? It's very frustrating to try to read about it, not the least of which because I keep getting home networking articles!
I would be very grateful if someone could help me understand the following assertion: 34:02 "Indeed any particle that escapes to infinity has a positive amount of energy, and therefore, as far as the outside observer is concerned, the infalling particle has a negative amount of energy". Why is that? Why couldn't the opposite randomly happen as well? I mean, the particle with positive energy falls in, and the other one escapes.
spiras73 I had this question forever too. Shouldn’t equal amounts of particles and antiparticles fall in, canceling each other out. The answer is that the whole particle/antiparticle picture is a simplified way of stating the math. Bottom line: both particles are made “real” by the BH’s gravitational field and so, the BH must lose mass as a consequence
According to today's video of S. Hossenfelder there is an issue with negative mass and negative energy - they very likely do not exist... The closest-to-reality-explanation I have ever heard was on a World Science Festival video and had to do with the different gravitational potential of the two virtual particles, but I did not get it at all, sorry.
Sean Carroll's wife is brilliant!!! She is an excellent communicator and knows her stuff....and you can tell she really loves her husband Sean, good stuff!
Firewall comes from the barrier between adjacent buildings through which utilities are allowed to move and not fire. It was later borrowed by information technologists.
Let me be clear when i defined Information as opposed to nearly pure energy... Im talking about a specific necessary restructuring of energy (just as matter can be a state of energy) for a requisite stable structure dependent on the space time topology, at a inner event horizon (were gravity is equal to the velocity of light) Ask this does a black hole preserve the law of conservation of momentum and then what does this mean in the case of the surface at the event horizon of such a object. To say were does spin go when transforming from a 3d space onto a 2d surface. Ironically at 52:20 they are simply speaking of relativity on the quantum scale. I don't see how they can not see this. Too boot a 2 dimensional surface that expands as information is added can also be directly considered from some hard to imagine point of view but no less valid as a one dimensional space. Which is also no less a way to describe a expanding filament of information. Which while less applicable then a two dimensional space in the context given of being within space time. It should be considered as the velocity of both mass and light falling in approaches c and thus even vibrational inertia becomes one dimensional as dilation maximizes. As you know a forward velocity can be described in terms of distance over time which in this case becomes constant and the motion is in the direction only of what is relatively forward or backwards in relation to a extreme curvature of space time which is almost surely circular. So that most everything spoken of depends on the topology of that curvature and from that what the properties such curvature would necessarily imply which could make a scenario valid or invalid. Consider were the center of gravity of such a structure described as this 2 dimensional surface originates from for a inward falling particle... In such a scenario the entire surface structure has most likely a gravity well moving at the speed of light at that surface and locality would be warped into essentially a line across the surface that wrapped around it as it spins in that case 3 dimensional locality also becomes 2 dimensional. Which is a much wilder thought then just the energy barrier around it as you are flattened into it and widened around it. Again this is just one logical structure from a specific space time topology at a information or uniformed energy state.
I've worked for one or two companies over the decades that, looking back, was just like jumping into a black hole. They pretty much ripped me to shreds in no time flat - toxic environments that is. Only it had a reverse effect in that it aged me, unlike a real black hole.
This guy is a beast. Able to give such good, professional speeches while presumably doing full-time academic research and being on the bleeding edge of quantum mechanics. e: 1:30:00 lol also answering impromptu grilling venomous double barrel highly technical questions.
I could listen to Sean Carroll all day, every day.
He seems to perfectly blend the mind-boggling complexity of his subject matter, with an ease and flow of delivery that makes it come across as comprehensively understandable at an engaging and relatable level.
This means so much to me.. I am a student from India with just no resources at all.. This empowers me.. Thank you everyone who is involved in this channel and video
Think of it as an apology from the Royals of England to your and any other country who had to endure their reign earlier in history. Also, you have the internet, the most powerful tool in history for learning, if you want it to be. Good to see that you have an interest in the basic fundamentals of everything, it's an extremely good character trait in my eyes. Schooling does count for something, but the basic human trait of curiosity is so much more important.
I am from India, but I have the resources! How is it that you don't? All we need in today's world is a laptop with internet connection and am sure u have that.
You got smart people in India. The most important resource :)
You speak english and have the internet... The world is yours
check out Leonard Susskind's lectures from Stanford. You, like the rest of us, have access to the best lecturers I the world. This is a wonderful age. Take advantage of it!
I'm very often, if not always, impressed with the RI audiences (especially the "kids") and their level of curiosity and general knowledge.
It happened first time in my Life that I watched a UA-cam video of one and a half an hour without skipping even a single second. Sean is a great explainer.
I traveled for nearly a week from an MSF mission in the Congo to attend these two's wedding in LA in the 2007 (ish?). Unique, beautiful ceremony. Took another nearly a week to travel back.
not sure that i've ever heard this topic presented as clearly, articulately and enjoyably as it was by ouellette in the above vid, just outstanding.
WTF at times it was a utterly incomprehensible USELESS explanation & nobody knew WTF he was talking about eg:
47:47 _"In a black hole, the 2-dimensional event horizon really does contain all the information you need, to talk about what's happening inside, according to the holographic principle. But it should be true even in this room, or the galaxy or the universe. & if that is true, locality is being dramatically violated, because there is a lot less that can possibly happen in this room than you thought could. You thought that something could be happening here & something could be happening there & different things could be happening at every point. But the holographic principle says: No, that's not true. 1 of the arguments for it, is if you imagine all of the different possible things that could happen most of them would have a lot of energy & would collapse to make a black hole. So there is an upper limit on the number of things that could happen in this room, & the size of the upper limit is proportional to the area of the walls around this room. So there is this hypothesis that all of physics really lives in a world that is 1 dimension lower than the world we actually see. & again, we are trying to make sense of this idea. We are making progress, but we are not completely there yet."_
_"The other idea that has come out of Black holes and argues against locality is called Black hole complementarity. Remember I said that, from the point of view of Bob from far away, he sees radiation coming out of the Black hole, and he says: well if I trace it backwards, it must have been very high energy radiation when it left the event horizon. Whereas Alice, in the conventional way of thinking about things, passes through the event horizon & sees nothing there, just empty space. So they had incompatible ways of describing the same situation. Bob thinks the event horizon is bubbling with high-energy radiation; Alice says there's nothing there. Black hole complementarity says: they are both correct. Black hole complementarity says they are different-sounding ways of giving equivalent descriptions of the same fundamental underlying reality, & that 2 things that are seen by 2 observers can look very very different, as long as the observers can never get together to compare notes. So what happens is, if you give Bob enough time to collect the Hawking radiation, & figure out what he thinks the horizon looks like, & you give Alice enough time to fall into the horizon. If Bob then says: alright, I've got some data; I know what's coming out of the Black hole. I am going to fly into the Black hole & tell Alice what I saw. It is too late. She has been spaghettified & crushed into the singularity. So these 2 observers see a very different thing happening in the world, but hey can never talk about it. Only we - God-like physicists, looking at the whole thing from afar, can give the bird's eye view on everything that is going on. That is the principle of Black hole complementarity. It's borrowed from the early days of quantum mechanics when Niels Bohr pointed out that you are allowed to measure position, OR you are allowed to measure velocity. You are not allowed to measure both at the same time. That was quantum complementarity; this is Black hole complementarity. So again, it's a violation of locality in some sense. It says that the right way to describe the world isn't what's happening here, & what's happening there, & what's happening there, and what's happening there, separately. What's happening right there can depend in a very dramatic way on who's looking at it & from what perspective. So somehow, all the information about what's going on in the world is not simply located in individual points in space. It's encoded in some cryptic way that we don't yet understand, & that's what we are trying to get at, by doing these thought experiments. The problem is, these 2 types of non-locality, don't seem to be enough to solve the firewall puzzle."_
I could listen to you all day, Sean. Thank you for all your talks. I get them off youtube. I watch many academic lectures in physics to better grasp these concepts of the nature of black holes & the reality of space-time. I only have a BA in music, but I do understand acoustic physics. So, I do have some foundation; just not a very strong one. I can't help but be excited about this stuff. It's what I do for entertainment, instead of TV & that nonsense. Thank you for your contribution to humanity, Mr Carroll
+CaptianKeyz Imagine where we could be as a species, if more people thought of this as entertainment instead of the absolute dreck populating TV, cinema, and radio, encouraging our children to follow in the footsteps of the great thinkers.
CaptianK
CaptianKeyz Godnrules
Yes!!!
dont 4 get to think 4 yorself,and reverse everything.
Congrats to the couple.Learned so much with Prof. Sean Carrol from 2007 to 2019. Excellent Podcast and lectures.
Sean is likely my favorite of his peers in terms of public communication; I enjoy his zeal and humor. Thanks for your time and thanks for uploading this!
He;s an idiot who doesn't even believe in the scientific method. You like him 'cause he's an atheist.
Sean’s enthusiasm and eloquence are to be admired. The trap he sets is you may believe everything he says.
Nikola Perkovic bringing up religion when nobody was talking about it. You seem like a rational person, give us your method to scientific research.
@@percestyler Sean Carroll doesn't believe in the scientific method?? That nonsense you wrote plus the typical name calling reveals it is in fact you who doesn't like him just because he's an atheist.
Everything he's said here is valid regardless of the existence of God.
@@iannamandwa7017 we are all american at heart.
I could watch Sean Carroll lectures all day. In fact, I think I will.
Same 👋
Same. I have the need to watch Sean Carroll lectures while doing something slightly less complicated than quantum mechanics, namely lace knitting. 🤣 Weirdly, it keeps me on task!?
First, I would like to say that having these kinds of lectures available on the internet is something that fills me with such a sense of pride in the human race that is refreshing. Thank you so much for this gift.
Second, I would like to point out a small correction. In the talk, Sean Carrol states the unfortunate link between the term "firewall" in this context and in computer science. Well, actually, the analogy is EXACTLY what happens in a computer firewall, except with a twist. The way a firewall works is it's a "membrane" any information wanting to pass from one network to another as to go through.
The default behavior is that any information is stopped. How is information stopped? It is "destroyed". This is the membrane acting "as nature intended". Destroying information is something we do all the time in computer science. How do we do it? We make heat. That's one of the reasons why your computer gets warm.
The twist is the trick to computer science. We get to cheat and decide what information is allowed to pass, basically by deciding to look at it instead of dissipating it. That's what makes it a very useful thing to protect "my precious universe" from the big bad things on the other side of the firewall.
So what? You think hell is on the other side? You "worry" me a bit... You are not religious, are you?
Not to be pedantic, but... Actually the packets that DO get through generate more heat than the rejected packets. All packets are equal before inspection. Dropped packets simply cease to be, but allowed packets have to be reassembled and forwarded to their destination, which requires more energy to transmit on down the line as either electricity or light.
LOL i just explained that firewalls have been around for some time (before computers)... if i remember right the first recorded instance was after londons great fire... adjacent buildings had to share at least one wall of stone, brick, or other masonry.
Onl no mm on
Information as stated in physics should be more fundamental than the term used in computer science. I guess.
This is amazing lecture! I stumbled upon this channel by accident but the skill, clarity and fervour of Mrs Ouellette had me anchor here and bask in the faint. warm glow of all the rest of the videos on the channel.
Thank you! Subscribed with a rare and true joy.
I well remember this joint lecture taking place in London, Sean and his wife were excellent and engrossing.
instaBlaster.
Wife?
Exceptional talk! Thank you to Ri for sharing this. A huge thank you to Jennifer Ouellette and Sean Carroll for sharing their thoughts and research with us.
0000000
Came to understand more about black holes, only to now understand we know seemingly less about black holes than we assumed in the past...I LOVE SCIENCE :D
Wonderful talk! The way Sean can convey such complex ideas in a nutshell with such clarity to the layman without missing a beat is an incredible skill. I think Feynman could do this too. Thank you for making these videos.
When listening to Sean's lectures, I deel like I listen to the world's best teacher. And you are a great couple.
My biggest dream at the age of 33 and just beginning to start my physics education is to contribute beyond the giants shoulders I've stood on for a year now. I have ADHD and the only thing I can keep focus on is absolutely everything to do with physics, mathematics, general relativity, quantum mechanics, and etc. It is a privilege to be able to learn so much for free these days. Godspeed.
Not to be rude but ADHD is lame
@@WebesJamm ha what?! Most random & weird comment ever wtf…
@@ermagherd1204 he's referring to it not being real because it's generally bad diet related etc than being a specific disease I think
@@Hakor0 I'd love to hear your information on it, the diet/brain correlation is interesting af but I never heard anything about ADHD being related
@@Hakor0xx
Nice talk but I also really enjoyed the question and answer period, could have enjoyed an entire vid of just that, he's good at answering questions cold off the cuff, and people in the audience are good at trying to narrow down ambiguities in language from the main talk to pierce the veil of the analogies a little bit while simultaneously sean immediately understands what they are getting at and resolves the ambiguity to clarify what is really being said.
He's good at collapsing the interrogative wave function.
i just watched all the sean carroll videos so I'm ready for my PhD in theoretical quantum physics.
He's on shrooms , just making stuff up - he fakes norble reel Goode...
Good luck with your Doctorate then!
@@garymingy8671 Well, you are certainly ''minging'' Gary!
@@geoden Hopefully I will spell his name correctly next time.
@@garymingy8671 Quite right, not interesting
The guy asking the question at about 1:17:00 ish, I like to think about it like this: Get a piece of elastic, and mark it close to the left end. Grab the elastic by either end and stretch it. The rate at which the mark moves away from your left hand is remarkably less that the rate at which your right hand is moving away from your left hand. Nevertheless, the elastic is stretching uniformly.
Sean and Jennifer are my two new favorite people. Bravo.
I watch RI videos during lunch. _So_ glad I picked spaghetti for this one!
I've read Jennifer's articles on Ars Technica for years, but this is the first time I've seen her on video. Crazy. Wonderful presentation, btw, and love her works on Ars.
I have watched this, maybe, 27 times, and I still find something subtle I didn't catch before! I would love to have dinner conversation with these two!
Or shout them whit tomatoes
You would never understand even after watching BILLION times Fool Cockroach 🤣🤣🤣🤣🤣😂😂😂😂😂😆😆😆
My meal would reach absolute Zero before I even start eating!
Wonderful lecture by both Sean and Jennifer. I've been a professor of psychology for 43 years and during the last 6 years I have become fascinated with quantum mechanics and cosmology. I would like a do over in life as a theoretical physicist. Unfortunately, that can't happen.
Perhaps all was not lost, as in another universe you did become a theoretical physicist! Although i bet in that universe you wish you had become a professor of psychology.
I'm 63 with a high school education who got D's in any math class I managed not to flunk and I intend to spend the rest of my days trying to understand this stuff! Enjoy physics on your free time!
Oh man seeing that thumbnail in my feed made me happy! I love listening to Sean Carroll! Thanks a lot RI!
Stunning duo work; they complement each other and their love for cats is adorable.
Thanks for sharing! This has been one of the clearer presentations of motivation for black hole firewalls and the holographic principle.
Drop the icrap please, it is disgusting.
I'm so happy that this has a million views.
Brilliant as always, Sean Carrol! Thank you, Ri, for publishing!
Sean Carroll is a nice talker :D I really enjoyed this talk ... Thank you for making available
She's brilliant...great lecture. Thank you. Always say thank you for such people.
Thank you very much I've watched this many times and will watch it many more times in the future.
I will spend the rest of the day picking up and reassembling the pieces of my blown mind.
Thank you!
I don't think the average person can understand the higgs mechanism. At university they don't even bother teaching it to undergrad students. I never understood any of this stuff until I started writting out the math and playing around with the numbers: Put in 0 or 1 and see what answers you get. It took e yaers to figure out how a massless particle can push" a massive particle but it can due to compton scattering. Once you do the math it makes sense.
It's true that some people are very logical without having a particular interest in mathematics. However, if you are interested in mathematics, e.i. are good at it, you very likely are logical. But, yes, Philosophers are very logical and great thinkers but aren't necessarily good mathematicians.
I am such a person. Good for me! XD
@@daveb5041 There are different levels of understanding. I can follow most public lectures about GR, black holes and quantum physics without a lot of difficulties, but there's no way I could do the math, and I'm well aware that public lectures are a very downsized version of what a physics student would have to learn. So it's like being around a black hole: From the perspective of an average citizen, I'm quite savvy in astrophysics and quantum theory, but from the perspective of a physics professor, I'm not even a noob. And, as we have learnt, both are right ;)
Let go , saniety ain't all it's cracked up to be or snot to bee swelling to extreame deminsions impossible to alloy smelt nor brazed , amen ,adue
Am I the only one that feels like I can remix music under her speach?
This is a conpliment, it's almost rap without the background music.
Plus what she's actualy saying....
Art man.
Sounding like an old-school dubstep intro
You can avoid spaghettification falling into a black hole by rotating at high speed. So remember, if you feel yourself going, tuck and roll, tuck and roll.
+kash krupa just enjoy the humor
I'll just measure the size of this black hole as I'm falling into it.....What? If you're going to die anyway, there is no down side. Tuck and roll, tuck and roll.
you can also avoid spaghettification by falling into an extremely large black hole, for a time anyways...
gamesbok o
gamesbok so
great talk .. cant get enough of these.. espeially sean .. he gets his point across very well
Must say again, how lucky we are to have Professor Carroll talk. Gifted, certainly. Additionally, my cat's name is Schroedinger; she's very much alive, and wants you to know that, other than for recreation, has never been in a box, and if she chooses to nap in one, please do not bother her to check her "state."
He's just good at vulgarization.
What an absolutely delightful presentation, David Tong
wrong video mate. I agree David Tong is good better than Carroll
Sean: "You've come very close to inventing what is called the Many Worlds Interpretation of Quantum Mechanics.."
Audience Member: "Oh, thank you very much. I have to text my mum, she'll be very proud!"
LOL.
That joke was so British. I can't think of anywhere else where someone would come back like that.
reply: "its alright son, its not any more testable now than it was 100 years ago for its originator"
BadTrip l look
Sean Carroll is a great communicator. So articulate.
The first time I conceptually understood Hawking Radiation and my mind is blown! The black hole rips virtual particles apart and it creates 2 real particles, 1 goes inside the black hole and the other goes outside, the one outside has positive energy and the one inside has negative energy, which is why it loses mass.
And I just took for granted that the black hole would lose energy.... I thought it would just get tired, not realizing that it if it's truly black it wouldn't lose energy.
It's charge that's positive and negative, but otherwise yes. The black hole loses its energy because Bob escapes.
@@alexlarsen6413 I thought I heard Sean say between 32 and 35 minutes that the charge of the two particles is opposite, the spin is opposite and also the energy is opposite. So the particles falling in have negative energy. I don't think enough time was spent on this oddity.Does that mean the firewall is comprised of negative energy? And how do particles with negative energy behave? And what happens when they interact with particles with positive energy? And can particles have negative energy inside a black hole but not outside? There are a lot of questions which were not dealt with in this talk.
You know I really appreciate someone who stops to take a moment and pause to reflect on the fact they're standing at the very desk where Michael Faraday once stood. Truly standing on the shoulders of a giant
“Sorry Dave” cracked me up! Brains and humor… thank you for a mind stimulating experience!
46:38 is it not the case that volume and outside surface area would necessarily increase proportionally? Not sure I understand why the distinction about increasing entropy being dependent on the (2D) area of the event horizon as opposed to the volume of its interior is so important. Could anyone clarify?
This is called the “no drama” principal, but Bob is just asking for it, trying to entangle with Carrie, when he knows Alice is waiting at the end of time for him.
.....that Carrie.........
RIP Dave...
Can't get enough of these videos
So, the first audience question is exactly what I wondered since ever, and I have the feeling Sam's answer is not addressing the problem. He says that Bob cannot see Alice anymore at some point and therefore Bob cannot exclude that Alice has not passed the horizon. But, we do not need visual evidence to know this. The equations of GR tell us that time dilation becomes infinite from the perspective of an outside observer, and so we can conclude that Alice never passes the horizon (from Bob's point of view). In fact, Bob can conclude (by calculation) that the BH must evaporate before Alice falls through the horizon. And this is the point that he does not address.
He always shift to "but Alice sees ..." and "Alice' point of view is relevant". But this is completely irrelevant to the question. The question is what an outside observer must conclude about the fate of Alice.
I'm no expert, but maybe the answer has to do with the uncertainty surrounding quantum mechanics. That the amount of time it takes for the black hole to evaporate can be calculated, but this is only an average, and it could be much quicker or much slower depending on the roll of the dice. Crucially that there is an infinitesimal probability that it will take an infinite amount of time to evaporate. Therefore you can never say categorically that the black hole has evaporated before Alice has fallen in.
Secondly that the photons reflected from Alice as she falls in will rapidly become very dim and infrequent - and perhaps these become merged with those emitted by the hawking radiation? Maybe if you shine more light on Alice as she falls in, this will allow you to see her better, but this also adds mass to the black hole, delaying the time of occurrence of evaporation.
Great talk by a great duo. RI thanks!
Incidentally, the cat observes, too.
Why is this at the end of the watchmen motion comic playlist
The Arctic Thing i have no idea o.0 maybe it’s a clue for where ozymandias is lol
Could the near infinite mass inside the event horizon disrupt particle interactions with the Higgs field, making them massless and allowing them to escape as Hawking radiation?
Once outside the event horizon they start interacting to regain mass, giving the impression the black hole is losing mass, and the mass acquired by the black hole is compression of the Higgs field?
Arttu Rajantie, a theoretical physicist at Imperial College London, revealed that when space-time is greatly curved, the Higgs boson increases in mass.
Could black holes be made up of Higgs boson's and everything else escapes as Hawking radiation?
Well, I'm not actually a physicist, only an enthusiast. Maybe that's the reason I haven't quite understood the contradiction between the Hawking's radiation principle with the integrity of information.
I mean, why is there a contradiction? Why information was considered lost by Hawking if the same information that falls into the black hole would eventually evaporated out from it as radiation?
Oners82 Well. Since I've posted this comment/question I've been studying and reading about these black holes paradoxes. I realized that actually the black hole evaporates not because it irradiates the matter that falls into ir, but because there is anti particles created from the virtual particles separation that happens at the event horizon. So what comes out of it actually comes out of the event horizon and not from inside. If I am right, that answer my question. So in fact, what is coming out of the black hole is not actually coming from inside. It's just the positive particle from the virtual particle that was created at the event horizon. Actually no information is coming out it, and that information that falls into like dust, meteors, etc., is being neutralized by antimatter created at the event horizon. So in fact, by this point of view information would really be lost.
Oners82 If the pair production is the process by which they evaporate, technically the information that comes out is not coming from the black hole. So how can he evaporate if not by the annihilation of matter inside it? I mean, the radiation that is coming out comes from the event horizon, not from inside, right?
Oners82 Or does the meteor that falls into the black hole is radiated out?
Oners82 I suppose there are two events regarding information falling into the black hole. First is the negative pair particles created at the event horizon which negative ones fall into. Second one is about the matter that comes from the space such as meteors, dust, stars and so on. These seems to me quite different events. If you consider the quantum entanglement principle to be preserved and use black hole complementarity to solve it, that would be OK with particles that are entangled. But a meteor is not entangled, is it?
Oners82
Well, I understood. Actually I kinda understood the whole point of my question (which was my idea that information would be lost through the contact with negative particles into the BH) on your first answer when you said that when positive and negative matter collide they release energy, so it enlightened my mind on how my thoughts about the hole process was wrong. Thanks for your consideration. I really am. Sorry for my dumbness :-)
I'm sorry. I haven't made my self clear. This would be a second question.
Actually this comparison I've made before, which may seem really stupid, in my mind has some sort of a sense. I've made this comparison because along Sean's lecture he talked about how it would feels like for someone to fall into a black hole. First he says that according to no drama principle (classical thought), a person would feel nothing at the no return point (event horizon). After this, he speaks about the Firewall concept, that Alice would be shred to pieces right at the event horizon. After that he proposes complementarity principle as a solution to this deadlock. Basically, the whole point of my comparison is that, his subject is considering entangled particles that would never talk to each other in such event. But what if we are talking about a non entangled particle falling. Would complementarity apply to that scenario? I mean, there wouldn't be a particle to "not talk to". Wouldn't it mess complementarity? It seems to me that complementarity, when it concerns whether a particle is shred to pieces or if it would feels nothing at the event horizon, only solves the cases with entangled particles.
Wow. Those two make a really nice dynamic duo!
Sean, Empty space is full of energy.
yup. the same level of energy evenly spread throughout. effectively making it not full of energy.
@@mammy24 lols, what funny way for a counter-argument.
I do have a question to Sean. The black hole tears the empty space, alice pop into the singularity while bob go away.
1. As nothing escapes from the black hole how could bob manage to do it.
2. After the empty space get torn down, what possibly could left behind on there.
Thank you.
Leave "Alice & Bob" to cryptography, you're just confusing the rest of us :p
as a student who has to deal with cryptography on the reg I am confused either way
Since I learned about the holographic principle, I have the vague idea that black holes and cryptography have very much in common.
P.P.S. At 1:03:00 he is talking about the gravitational redshift of light/radio signal from Alice to Bob. But that's not at all important in this context. What is important is what HAPPENS from a certain observer's point of view. And that can always be deconvolved from light (or radio etc.) signals sent out from both parties (Bob & Alice).
And on that matter, I'd be delighted to hear the opinion of these experts here.
she has the most inviting voice for this topic.
Love her laugh too..
Amazing talk! Thanks, Sean Carroll!
they are such a nice couple!
i love them both
you would have to walk in their shoes to know.
Frankly, I don't understand the statement at 35:18. (And ok, that might be only my problem.) Two entangled particles that are either "red" or "blue" when observed, represent exactly 1 bit of information, not 2 bits. That 1 bit is preserved in Bob. Alice is not needed outside the event horizon to carry that information, she is redundant. (Sorry, Alice.) So why would we need Carrie? Does Bob somehow "know" that he once was entangled with a particle that is now lost? Is being entangled a measurable property of one particle? I thought it's not. I'm sure there's a reason and the talk is correct. I just don't feel it is explained here--and it seems crucial for understanding.
I love the fact that quantum mechanics is now becoming general knowledge.
Really? Shit I gotta catchup
even 5 year olds know the Dirac equation! ;o)
+Steve Bergman What is QW? It that QM upside down?
+NicenEasyuk Maybe, but we, the general public, is still outdated since QFT is fashion among physicists now...
Quantum Woo are the metaphores that are used to make people understand QM a bit more. Unfortunately, those metaphores are never 100% accurate. Even I am guilty of this for parts of QM.
I don't understand how information is lost in the black hole in terms of virtual particles. If the particle that goes in is entangled with the particle that escapes, don't the properties of the escaping particle that are measured give us the exact information of the particle that doesn't escape(as the entanglement causes those properties to be opposite to the ones measured). Plus surely if they come from empty space, isn't the 'total' information content 0? And for objects falling in, how would that information become encoded in the virtual particles( hawking radiation)?
Thanks for the clarification!
This video, inspiring the deepest thoughts mankind can imagine - 100k views. Nicki Minaj, Gangdam Style, and Pewdiepie - billions of views. This is harder to conceive of than any topic in this video.
Henry Rollins said it best...disgusting, disgusting on an epic scale.
+Daitaigenjitsu You just have to go off-topic, don't you?
I wouldn't call it disgusting, I would call it natural. Evolution, even cultural evolution, is very gradual. You can't fault people for behaving like the primates that they evolved from.
Guess most of the people are scared off for life from physics (or science in general) in high school. Remember your physics classes? They didn't have much in common with lectures like this, did they? Plus, most of the times they didn't even cover interesting stuff.
I think science teachers could learn a lot from UA-cam.
My favourite quote from Oscar Wilde: "We are all in the gutter but some of us are looking at the stars".
You know there's a lot of physics in the steps of gangdam style lol
Sean is a really great explainer.
Is there a copy of the universe in which we fully understand quantum mechanics?
Most interesting, makes one think of the positivities quite exciting, thank you both!
if even light cannot escape a black hole
then being in the black hole is being showered by light :O
Absolutely! You are SPOT ON!!!
@@Lynettjames yes!! glad someone understands what I meant
Great talk Sean, thanks.
it has Taken this Man Quite some time and Many Explanations to Say that Somewhere in this Universe and Possibly somewhere outside this Universe he is Both Correct and Wrong...LOL
Excellent presentation. Beautiful and intelligent.
WANTED DEAD OR ALIVE
SCHROEDINGER CAT.
$1000 REWARD.
Andrew Galloway now that is clever. To bad you didn’t post this 5 years ago. It would have a million likes!
Can i get it if hes dead and alive ?
For me ? Or the cat ?
Thank you both, a question I'd like to put forward begins with a photons red shift. Matter isn't expanding but lights wave length is, could light also suffer a loss of energy in this process to contribute to Dark Energy. Apologies if this is ignorant, again thank you both for the discussion.
Editing tip: Either show the slides long enough to be read or not at all.
exactly
Pause the video.
El gamol asymmetric key exchange protocol 44:00 possible way to see the entanglement and keep locality.
Jennifer Onellette should avoid self deprication, and right from the start: "I'm not worthy." (Nervous laugh...) Of course, you are worthy!
The producers of this presentation should consider different microphones. Headsets are distracting.
Peter Wexler I think that's the unfortunate Dunning Kruger effect.
Peter Wexler it's like giving some kids a short basketball lesson, only there's another big one by Michael Jordan after you, it's safe to have some self deprecation here,
Oners82 "I think you are probably the only person who gives a shit, let alone even noticed the headsets." Anyone who's got at least an undergrad degree in Speech Communication will notice, and half of those will "give a shit."
Oners82 I think that I have heard enough out of you. Later daze.
Peter Wexler If she cannot lift the Hammer, she is not worthy.
Simple as that.
I have a question: HOW CAN YOU PRESUME THAT BOB COULD BE ENTANGLED WITH CARRIE?!
First of all, I would like to mention that I sucked HARDCORE at maths, physics & chemistry in school, so I apologise if my question is dumb
Here it goes
Time reference in video: min 35:16
OK SO I GOT THIS PART:
1)Bob is entangled w Alice
2)Alice gets sucked into black hole => Alice has - energy => Bob has +energy
3)Bob is then entangled with Carrie that used to be entangled with Dave that was also sucked into black hole
WAIT WHAT?!
If Dave is in b hole => Dave is -energy => Carrie is +energy
SO HOW CAN YOU PRESUME THAT BOB COULD BE ENTANGLED WITH CARRIE IF THEY'RE BOTH +ENERGY?
Is it not a necessity for entangled particles to be of opposite energies?
i believe what was presumed was the very fact Bob CANNOT be entangled with Carrie....
Hey it's Sheldon and Amy
What is information? Is it what a thing is made of? Appearance to an external viewpoint? Hight, depth, length, mass?
Crib sheets for midterm?
light is not a constant speed. That is disproven..
In a vacuum, maybe.
Two questions come to mind.
1. As a virtual pair is crated on the edge of the event horizon. Why is it always the positive energy particle that escapes and the negative particle that falls in the hole?
2. When is the information actually lost? If one particle leaves and the other one falls in the hole and they are both entangled. Would we not know the state of the one in the hole by measuring the one that escaped.
She reminds me of Tina Fey.
RonJohn63 she reminds me of a white noise machine
Kinda looks like her. I thought the same.
Was just thinking the same!
I don't quite understand why in QM it is a problem, when particles or information goes into a black hole and just stucks there. Does this mean the information is destroyed? Couldn't it be that it is just out of reach for us?
And why it is a problem when information gets destroyed anyway?
Is there a link to a document or a video which explains this well and in detail?
The only one who proposed a real new way of thinking about all this are Susskind and T. Hooft. Carrol is a good explainer for the masses, but he is no discoverer.
Good thing that you are. ;)
In many discussions about black holes, there seems to be an assumption that the event horizon is a clear boarder that being the same to all observers. However this seems to be self contracting since by definition the "maximum" event horizon is the border where inside it light can't escape to infinity. However if you are closer to that horizon (but not entering it), the light inside that border can still reach you since you are not infinitely far away. However there should still be another horizon relative to your position so the light inside it can't reach you. This horizon should be inside the "maximum" horizon, and the Hawking radiation temperature should be higher than what was observed from infinity. Therefore, if getting closer and closer to the black hole the temperature should become hotter and hotter but you will never be able to "touch" the horizon until it becomes so hot that it destroys you.
Is there anything wrong in the above thought experiment?
Excellent talk.
I don't understand how you can have entangled particles where one particle can have positive energy and the other entangled particle has negative energy. How can a particle have negative energy? How can anything have less than zero energy? Sean said if you initially have two virtual particles just outside the event horizon that they are "ripped apart" as they reach the event horizon. In the process they are transformed into two real particles, one having positive energy (Hawking radiation) ejected outward from the event horizon and one having negative energy falling into the black hole and into the singularity. I understand the concept of conservation of energy from thermodynamics. Is it the case that the inward falling particle has a negative energy relative to the outward ejected particle's energy or that it has a negative energy relative to absolute 0 K or relative to the energy level of the surrounding vacuum space? If anyone could help me understand this it would be greatly appreciated.
Anti matter has negative energy to allow for annihilation to occur. look into particle physics for more detail. I believe feynman does a good lecture on it
Yes. This is how you talk about black holes. Loved the talk. Very insightful and "down to Earth". Kudos! ^_^
No it isn't. A lot of this video is incomprehensible. DrPhysicsA did the best video on BH.
E.g. Carroll said this gooblegook:
47:47 _"In a black hole, the 2-dimensional event horizon really does contain all the information you need, to talk about what's happening inside, according to the holographic principle. But it should be true even in this room, or the galaxy or the universe. & if that is true, locality is being dramatically violated, because there is a lot less that can possibly happen in this room than you thought could. You thought that something could be happening here & something could be happening there & different things could be happening at every point. But the holographic principle says: No, that's not true. 1 of the arguments for it, is if you imagine all of the different possible things that could happen most of them would have a lot of energy & would collapse to make a black hole. So there is an upper limit on the number of things that could happen in this room, & the size of the upper limit is proportional to the area of the walls around this room. So there is this hypothesis that all of physics really lives in a world that is 1 dimension lower than the world we actually see. & again, we are trying to make sense of this idea. We are making progress, but we are not completely there yet."_
_"The other idea that has come out of Black holes and argues against locality is called Black hole complementarity. Remember I said that, from the point of view of Bob from far away, he sees radiation coming out of the Black hole, and he says: well if I trace it backwards, it must have been very high energy radiation when it left the event horizon. Whereas Alice, in the conventional way of thinking about things, passes through the event horizon & sees nothing there, just empty space. So they had incompatible ways of describing the same situation. Bob thinks the event horizon is bubbling with high-energy radiation; Alice says there's nothing there. Black hole complementarity says: they are both correct. Black hole complementarity says they are different-sounding ways of giving equivalent descriptions of the same fundamental underlying reality, & that 2 things that are seen by 2 observers can look very very different, as long as the observers can never get together to compare notes. So what happens is, if you give Bob enough time to collect the Hawking radiation, & figure out what he thinks the horizon looks like, & you give Alice enough time to fall into the horizon. If Bob then says: alright, I've got some data; I know what's coming out of the Black hole. I am going to fly into the Black hole & tell Alice what I saw. It is too late. She has been spaghettified & crushed into the singularity. So these 2 observers see a very different thing happening in the world, but hey can never talk about it. Only we - God-like physicists, looking at the whole thing from afar, can give the bird's eye view on everything that is going on. That is the principle of Black hole complementarity. It's borrowed from the early days of quantum mechanics when Niels Bohr pointed out that you are allowed to measure position, OR you are allowed to measure velocity. You are not allowed to measure both at the same time. That was quantum complementarity; this is Black hole complementarity. So again, it's a violation of locality in some sense. It says that the right way to describe the world isn't what's happening here, & what's happening there, & what's happening there, and what's happening there, separately. What's happening right there can depend in a very dramatic way on who's looking at it & from what perspective. So somehow, all the information about what's going on in the world is not simply located in individual points in space. It's encoded in some cryptic way that we don't yet understand, & that's what we are trying to get at, by doing these thought experiments. The problem is, these 2 types of non-locality, don't seem to be enough to solve the firewall puzzle."_
Does anyone know what the current state of the firewall hypothesis is? It's very frustrating to try to read about it, not the least of which because I keep getting home networking articles!
Love reading all the experts comments on here ... way to go youtube physicists
Brilliant as always, Sean Carrol! Thank you, Ri, for publishing!
I would be very grateful if someone could help me understand the following assertion:
34:02 "Indeed any particle that escapes to infinity has a positive amount of energy, and therefore, as far as the outside observer is concerned, the infalling particle has a negative amount of energy".
Why is that? Why couldn't the opposite randomly happen as well? I mean, the particle with positive energy falls in, and the other one escapes.
spiras73 I had this question forever too. Shouldn’t equal amounts of particles and antiparticles fall in, canceling each other out. The answer is that the whole particle/antiparticle picture is a simplified way of stating the math. Bottom line: both particles are made “real” by the BH’s gravitational field and so, the BH must lose mass as a consequence
According to today's video of S. Hossenfelder there is an issue with negative mass and negative energy - they very likely do not exist...
The closest-to-reality-explanation I have ever heard was on a World Science Festival video and had to do with the different gravitational potential of the two virtual particles, but I did not get it at all, sorry.
Sean Carroll's wife is brilliant!!! She is an excellent communicator and knows her stuff....and you can tell she really loves her husband Sean, good stuff!
Firewall comes from the barrier between adjacent buildings through which utilities are allowed to move and not fire. It was later borrowed by information technologists.
Why does the thumbnail photo not feature or at least include Jennifer Ouellette?
its bias
also I like sean.
who is a great communicator
and learned a lot from him when I was his student in Caltech
Let me be clear when i defined Information as opposed to nearly pure energy... Im talking about a specific necessary restructuring of energy (just as matter can be a state of energy) for a requisite stable structure dependent on the space time topology, at a inner event horizon (were gravity is equal to the velocity of light) Ask this does a black hole preserve the law of conservation of momentum and then what does this mean in the case of the surface at the event horizon of such a object. To say were does spin go when transforming from a 3d space onto a 2d surface.
Ironically at 52:20 they are simply speaking of relativity on the quantum scale. I don't see how they can not see this. Too boot a 2 dimensional surface that expands as information is added can also be directly considered from some hard to imagine point of view but no less valid as a one dimensional space. Which is also no less a way to describe a expanding filament of information. Which while less applicable then a two dimensional space in the context given of being within space time. It should be considered as the velocity of both mass and light falling in approaches c and thus even vibrational inertia becomes one dimensional as dilation maximizes. As you know a forward velocity can be described in terms of distance over time which in this case becomes constant and the motion is in the direction only of what is relatively forward or backwards in relation to a extreme curvature of space time which is almost surely circular. So that most everything spoken of depends on the topology of that curvature and from that what the properties such curvature would necessarily imply which could make a scenario valid or invalid. Consider were the center of gravity of such a structure described as this 2 dimensional surface originates from for a inward falling particle... In such a scenario the entire surface structure has most likely a gravity well moving at the speed of light at that surface and locality would be warped into essentially a line across the surface that wrapped around it as it spins in that case 3 dimensional locality also becomes 2 dimensional. Which is a much wilder thought then just the energy barrier around it as you are flattened into it and widened around it. Again this is just one logical structure from a specific space time topology at a information or uniformed energy state.
THANK YOU BOTH...!!!
This is extremely interesting
I've worked for one or two companies over the decades that, looking back, was just like jumping into a black hole. They pretty much ripped me to shreds in no time flat - toxic environments that is. Only it had a reverse effect in that it aged me, unlike a real black hole.
This guy is a beast. Able to give such good, professional speeches while presumably doing full-time academic research and being on the bleeding edge of quantum mechanics.
e: 1:30:00 lol also answering impromptu grilling venomous double barrel highly technical questions.