"a black hole is a mirror and the way it's a mirror is if light a photon bounces off your face towards the black hole and it goes straight to the black hole just Falls in you never see it again but if ..."

"you are part of the Harvard black hole initiative which has theoretical physicists experimentalists and even philosophers so let me ask the big question what is a black hole from a theoretical from an..."

"it definitely happens we've seen those regions we have spectacular pictures especially in the last several years of those regions um they're there in fact they're up in the sky thousands or millions o..."

"um if you're on the Earth and you're on a rocket ship leaving this the surface of the Earth and if we ignore the friction from the air um if your rocket accelerates up to 11 kilometers per second that..."

"interesting there's a lot of interesting things here first of the speed limit how Wild is it to you if you put yourself in the mind in the time of Einstein before him to come up with a speed limit of ..."

"beautiful ideas that physics have this very hard to get yourself back into the mindset of course Einstein was confused about many many things doesn't matter if you're a physicist it's not how many thi..."

"well what a hundred years later what is coordinate transformation as it was a hundred years ago to today let's imagine I want to draw a map with pictures of all the states and the mountains and then I..."

"just based on either one okay space or time that gets very tricky and Einstein uh didn't didn't didn't have it right and in fact he had an earlier version of general relativity in 1914 which he was ve..."

"crashes everything becomes infinite there's two so the questions are just no good there now that's actually not a bad thing it's a really good thing and let me explain why um so it's an odd thing that..."

"trying to get as close as possible yeah so you think are you saying objective truth doesn't exist in this world we could discuss that but that's a different that's a different thing um we wouldn't say..."

"would collapse it's Quantum you know so that's a huge correction there sure so every Theory gets corrected as we learn more dude just be no reason to suppose that it should be otherwise well how is th..."

"so it's a good thing that the theory drives itself that it predicts its own demise Newton's gravity had its demise there were regimes in which it wasn't valid Maxwell's electromagnetism had its demise..."

"the failures the edges are wonderful because that keeps that keeps us in business so that one of the things you said I think in your Ted Talk that uh the the the fact that quantum mechanics and uh and..."

"understood uh there was the periodic table there was but in fact that was such a rich thing um that uh well so that what a lot of exciting stuff happened around 1920. it took it took the whole it took..."

"gravitational field the gravitational force is instantaneously transmitted across the entire universe so you could you know if you had a a a a friend on you know in another galaxy with a very sensitiv..."

"seem the the tension the contradiction there seems to hint at some deeper deeper thing that's going to be discovered in the century yes because that one has been understood since the 50s poly was the ..."

"uh what are all the different unification efforts okay so again five questions yeah it's a theory that describes everything with astonishing accuracy it's the most accurate theory in the history of hu..."

"particle to be observed was the Higgs particle served like a over a decade ago the Higgs is already a decade ago I I think it is yeah wow time flies but you better check me on that yeah it's it's true..."

"so precise it's predictions it's hard to imagine something yeah yeah yeah and it was all based on something called let me not explain what it is let me just throw out the buzzword renormalizable quant..."

"uh is string theory and its cousins and we don't know what or if in any sense String Theory describes the world the physical world but we do know that it um is a consistent reconciliation of quantum m..."

"are some interesting developments uh what do you see as the also the future of string theory and what is string theory well the basic idea which emerged in the early 70s was that if you uh you take uh..."

"one thing I can't explain is how wonderfully precise will the mathematics is that goes into describing String Theory we don't just wave our hands and throw strings around and you know there's some ver..."

"then that string theory was an interesting sort of toy model for putting quantum mechanics and general relativity together on paper but um but that it couldn't describe some of the very idiosyncratic ..."

"that it isn't parody of invariant and string theory it was thought could not tolerate that and um then it was learned in the mid 80s that not only could it tolerate that but if you did things in the r..."

"eventually sort of found its place and it's also true of Einstein's theory of general relativity you know he had the wrong version of it in 1914 and he was missing some pieces and you wouldn't say tha..."

"and and it would I mean another thing that I didn't mention about strings theory is of course we knew that it solved the Infinities problem and then we later learned that it also solved Hawking's puzz..."

"black holes yeah so that is a very interesting story I was interested in black holes before I was interested in String Theory I was sort of a reluctance strength there is in the beginning I thought I ..."

"at it you know you can't you can't grasp it all in the beginning and and um so our understanding of string theory in uh uh in 1985 was almost all about uh you know weekly coupled waves of strings coll..."

"20th century physics I don't think there are many equations that made it to headstones and and they're really Central equations and you put them together and you get a formula for the number of gigaby..."

"uh where where's yeah and what's information I'm liking this ask five questions to see which one you actually answer oh okay I'm going to ask you about that I should try to memorize them and answer ea..."

"exactly and that's the holographic principle the universe is so weird and that's the holographic principle that's called the holographic principle that is it's the area we're just jumping around what ..."

"problems in uh physics is to you know apply or even formulate the holographic principle for more realistic well black holes are realistic we see them but um yeah in in more General context so from a g..."

"so we can have curvature in a way that mixes up space and time and that's kind of hard to visualize because you have to step what a couple of Dimensions up so it's hard to you have to step a couple bu..."

"all the unit matter in it will be expanded away but it will continue to expand because uh well they would call it the dark energy Einstein would call it a cosmological constant in any case that the in..."

"well again the same thing be said about all all the constants all of the content be said about gravity can't they be said about the speed of light like why is the speed of light so slow so fast so slo..."

"the world we Intuit the World Through The Eyes of the these biological organisms I guess mathematics helps you escape that for a time but ultimately isn't that how you wonder about the world absolutel..."

"have a theory that corrects it string theory and now sort of was the Moment of Truth well when we first discovered String Theory we knew we knew from the get-go that string theory would correct what E..."

"string theory because if it hadn't given the answer that beckenstein and Hawking said it had to give for consistency String Theory itself would have been inconsistent and we wouldn't be doing this int..."

"yeah it would have been a major a major uh change in the way we think about string theory if it and it was a good thing that you know one supposition that the world is made of strings solves two probl..."

"information and um that is the one that we solved in some cases so it's sort of like you know your your smartphone how does it store at 64 gigabytes well you rip the cover off and you count the chips ..."

"just to clarify the storage is on the plate on the flight on the holographic plate and then it projects somehow inside the the bulk the the space time is the Hologram the Hologram but man I mean did y..."

"that is the Great thing about being a theoretical physicist is anybody can very quickly stump you if they going to the next level of wise yeah so if I can just keep asking yeah you could just keep ask..."

"you you co-wrote co-author the paper with Stephen Hawking called soft hair on black holes yes that makes the argument against Hawking's original prediction that black holes destroy information can you..."

"that is every black hole in the universe is described just by its mass and spin they wrote they can also rotate as was later shown by Kerr and um and this is very much unlike a star right every Star o..."

"and that means when you throw some in Einstein's description of them which we think must be corrected and um if you throw something into a black hole it gets sucked in and if you uh throw in a red boo..."

"Hawking and I showed and also Malcolm Perry um is that one has to be very careful about what happens at the boundary of the black hole and this gets back to something I mentioned earlier about when tw..."

"the soft hair right so and soft is the word that is used in physics for things which have very low energy and these things actually carry no energy there are things in the universe which carry no ener..."

"about life uh from uh having worked with Stephen Hawking well he was one of my great teachers of course he's he's older than me and I was I was reading his um his textbooks in in um in graduate school..."

"sometimes he was wrong do you feel pressure from the community so for example with strength Theory I was very popular for a time there's a bit of criticism or is less popular now do you feel the force..."

"um and uh people are always sort of disagreeing with me and they're usually right but I'm right enough and like you said the contradiction ultimately paves the path of Discovery yeah uh let me ask you..."

"I mean why would there be math that had no physical manifestation it seems a little odd right you have two kinds of math some that are relevant to the real world where they don't have to be contradict..."

"an answer to the question and everybody will agree what the answer is and that there's a an algorithm for for getting there um not that these other questions aren't interesting um and they don't someh..."

"Multiverse or uh you can have a lot of kind of very far out there questions or your gut and Instinct and intuition says that maybe in 1500 200 years you'll be able to actually have strong experimental..."

"is a very different thing than saying do this experiment here's a billion dollars and after you do it we'll know whether or not strings are real but I think it's a crucial difference it's measurable i..."

"the real world and you know when I started out in graduate school I said what is the what is the most interesting problem that there might be the deepest most interesting problem that there might be p..."

"and it could happen that we I don't think we're gonna light see the heterotic string Spectrum in an accelerator but but it could be that things come around and and uh in an interesting way and somehow..."

"person taking every route and you know if somebody on another route uh uh find something that looks really promising you know I'm gonna make a Portage over the mountain and get on their street you kno..."

"completely and it's just that's where the philosophy done right I think is very useful that's where even the you know these thought experiments which is very fun and sort of the the tech sci-fi world ..."

"complexity all right he's totally right about that yeah and I and physicists I guess don't have don't know what to do with that don't know do with cellular automata because you can describe the simple..."

"but if you look at the standard model it's kind of a laundry list with neutrino masses and all that stuff they're they're hundreds of free parameters where do they come from is there an organizing pri..."

"good way to improve your understanding because you know you've understood it if you could do the predictions yeah one of the interesting things that might come to a head with is our artificial intelli..."

"predictor yeah like uh you want to play Just within AI yeah AI people are trying to understand what it is that the AI Bots have learned in order to produce whatever they produce for sure but you still..."

"what governs the whole thing um and maybe you can ask it a question it'll be some kind of Hitchhiker's Guide to the Galaxy type answer uh that you know it's a funny world uh we live in of course it's ..."

"but a simple algorithm a relatively simple algorithm to predict everything so for me it would be a sad day if we arrived at that without answering some deeper questions sure of course it definitely is..."

"because we we you know one of the one of the basic principles the physics is determinism that the past follows from the the present follows from the past the future follows from the present so on but ..."

"have a trick that that helps us with that puzzle do you think we'll be able to sneak up to the the origin of the universe like reverse engineer it from experimental from theoretical perspective like o..."

"something that we we you know we're getting a pluses in sure let's pretend we live in a world where in a hundred years we have an answer to that yeah what would that answer look like who what departme..."

"since uh you highlighted the issue with time and the origin of the universe do you think time is fundamental or or emergent I think ultimately it has to be emergent yeah what does it mean for time to ..."

"Community we're not getting a pluses on these efforts but what we'd like to do is to see um examples in which the extra space-time dimension is time in other words usually what what we understand very..."

"you co-authored a paper titled Photon rings around warped black holes first of all whoever writes your paper titles you like uh the soft hair and the and and the term black hole in the Big Bang you're..."

"which started out in an effort to understand the image that they'd seen so it's a great thing for somebody like me a theoretical physicist lost seemingly lost in string land to be presented with an ac..."

"in the process of talking to them and thinking about how light behaves around a black hole it they black holes just have so many magic tricks and they do so many weird things and the photon ring is am..."

"stringy black holes but they have a somewhat different character with a stringy black hole the the black holes that describe us the black holes that are contained in string theory and they have differ..."

"it'll swing around the back and come back to you and you see yourself from the photon that went around the back of the black hole but not only can that happen the black hole the photon can swing aroun..."

"so you can go there a thousand times wearing different clothes but each time there will be the same relation between the subsequent images and that is how we're going to learn about the black holes we..."

"region around a black hole is crazy it's not like in this room right the curvature is everything you know you spend probably enough time with the math and the photons can you put yourself in that spac..."

"but you're not ripped apart the fact that this was just nonchalantly stated is is just beautiful like two biological systems discussing uh which level of curvature is required to rip apart said biolog..."

"soluble examples in this case in an example in one lower Dimension where we can handle the equations better that the quantum system that describes the black hole should correspond to a region of space..."

"gotta like do everything let me ask you another sort of philosophical type question but not really actually um it seems that thought experiments are used so it's not just mathematics that makes progre..."

"problems that were not solvable the ambition of Youth yeah what what what made you fall in love with physics at first if we can go back to the early days you said black holes were there in the beginni..."

"in hundreds of years yeah yeah are you able to by the way um love the idea the exploration of ideas themselves without the names yeah yeah that's what I'm saying so I have not I hope someday but I hav..."

"interesting thing about you is and I have been very excited about things which turned out to be completely wrong you know well that's the the excitement is a precondition for uh for breakthroughs um b..."

"about it you know man yeah this is a really frustrating thing when we think from uh me as an AI person you start to think about what is intelligence which is consciousness you start to sometimes again..."

"build a brain so the process of engineering intelligence not just the neuroscience perspective of just looking at the brain but trying to create it uh but yeah that story hasn't been written almost at..."

"different way let me ask you um kind of a heavy question for a physicist but one on nuclear weapons just in general what do you think about nuclear weapons where like philosophical level where brillia..."