Sir Roger Penrose on Blackholes and The Big Bang | Joe Rogan

it's not to mislead you there's a mathematical theorem cover the hairy dog theorem hairy dog theorem yes I mean SSF ocular terminology but you think of a something which is topologically a sphere that means you see you imagine a dog shape but you could sort of move it around with a piece of plasticine until it looked like a sphere it doesn't have holes in it okay forget about this digestive system you see you're thinking about the surface outside and then you're out the problem is you try to comb the hair on the dog all the way around and the theorem says there's got to be somewhere where the hair doesn't lie flat and you try it on the sphere there's got to be a point where where the hair makes a kind of singular point so it's a bit like that you have no idea where the singularity is but you know from general topological reasons that there's got to be one somewhere and that was the sort of argument that I produced and I guess a lot of people a little bit of trouble because they've never seen this kind of argument and a lot of people picked up on it and particular Stephen Hawking and it became for a while a lot of many people working on it I guess it's not so popular now because they probably would run out of serums the idea of a singularity like is when you see something like a quasar or the the center of a galaxy nam and we were talking about a black hole when you say a singularity what exactly are you do you mean by that with a normal expectation is that you have a place like in the middle of the Oppenheimer Snyder dust cloud that a point there where the density becomes infinite and so the curvature of space-time becomes infinite so you have a place where the equations run away and they go to infinity and you say well something's gone wrong but maybe initially it was in these very symmetrical cases but but you could show by these indirect arguments that somewhere something's got to go wrong you can't continue the equations of and they got stuck right in that place where they go infinite door what in detail happens in theorems don't tell you they just say that something goes wrong and that's what we call a singularity and if a black hole is larger or smaller the singularity remains constant it remains in in there it remains in there but it's not measurable in terms of its actual size so whether you can measure its size very well cuz its size that's that's an intriguing question you might say the size has gone to zero right it could be quite complicated irregular not like the original obernai Messiah or my soldier something even then the point is the wrong point of view but let's not go into that now there is something about the structure of these things you can say they're not all the same no then the singularities and all the same but the black holes are not all the same they're not all the same but they this one of those strange things about black holes is that if you let them settle down they're not all the same to begin with but they're not many different things they can settle into they can have rotation they can have a certain mass and the mass translates into the size of a diameter of the hole and you've also got rotation so they can rotate and this is hardship found the non rotating ones and it was Roy Kerr an Australian who first produced the solution for a rotating black hole rotating yes a rotating one but then you see the remarkable thing is that's what they settle down to so they're good theorems which tell you that the general black hole to be very complicated fairly rapidly will settle down and become one of these curved solutions the rotating black hole I remember when I first saw that documentary I saw the when they were discussing the the shape of these galaxies and that the center of it had this supermassive black hole that was slowly devouring the galaxies yeah I mean it's it is an unbelievably beautiful yet simultaneously terrifying idea is that there's this yes infinite power in the center of infinite mass that's absorbing slowly but surely everything around it yes but it's not infinite mass the mass is quite well defined and it's not infinite but yeah I was a good question I mean if you wait forever how much of the mass actually gets swallowed by the mine hole you see I think the pictures to think not just in one galaxy but a cluster mmm you see our galaxy has this four million solar mass black hole and we are on a collision course with the Andromeda galaxy and I don't know how long but many but some time in the future yes the black holes will probably spiral into each other and there'll be one big one so it's definable mass but in infinite density and that this point which were they were speculating that this could possibly in the center of the supermassive black holes now if you could go through that there would be another universe well yes that's all nice speculation it's a nice romantic thought is it more whoo I'm afraid so so good yes I know well it's a shame for science fiction yeah makes a nice little it's just thing that we try to make things more complicated than they are because they're so complicated as it is like dark matter for instance it boggles the mind that we don't really totally understand what 90 plus percent well that's a good question yeah what is that stuff well you want me to tell you my theory yes please well you see it's part of a story which I don't know about 15 years ago I must have years a passing by I can't remember how long ago now so I had this idea you see the universe as a whole is expanding now early in the this century don't ask me dates again some people by observing super not supernovae saw exploding stars very very far away they found out that the universe is actually accelerating in its expansion and some people found this very mysterious on the other hand it's in all the cosmology books because there is that expectation you see in 1915 I saw and produced his general theory in 1917 he introduced what's called the cosmological constant so you think of a it was called lambda you think of a v-shape turned upside down which is remember and he introduced this term for the wrong reason because at that time people weren't there was some indication in the universe was expanding but not very clear and Einstein I guess maybe didn't know believe it and this the couple's observations hadn't yet come to make a convincing case of the expansion so I thought well maybe the universe is static it's kind of philosophically nice to think that it's sitting there all the time and he couldn't make it do that so he had to introduce this term called the cosmological constant and he did that and then not while very much longer after this Hubble showed that the universe does seem to be expanding and Einstein regarded this lambda term as his biggest blunder which is an irony because it turns out that this term is probably the explanation for the expansion of the universe we now see so it's what people call dark energy I don't like the term very much because it's neither dark nor proper energy in any clear sense but still don't let's not worry about that right it would so it's a it's an odd term yes I think so it's a little confusing because it's dark matter as well which is quite different you know shamash yeah I'm confused with the dark energy as it's called or the cosmological constant which as far as we can tell it is completely consistent with the observations it's a positive number very small but it seems to be producing this expansion and I'm quite happy with that viewpoint because it leads to a picture which I've been trying to plug for a while now maybe up to 15 years I can't remember the idea I know it's hard to explain but let me try it came about because I was worrying about the remote future and I was thinking okay when these black holes are on this wall I love all the stars and they're just sitting around and what's the most next exciting thing happening well the Hawking of apparation they're going to radiate away Stephen Hawking showed that black holes had this temperature extremely cold how many of these enormous ones are absurdly cold much colder than anything made on the earth and but when the universe expands and expands and expands it gets colder than the black holes and so those black holes get become the hottest hottest things around and so they radiate away very very slowly this Hawking radiation and that carries energy and so they shrink and shrink and they shrink and finally they disappear with a pop I said pop is probably a pretty big explosion but that not that big from the cosmological that's the physical scale so they disappear well it may be you've been pretty boring when you're sitting around waiting for the black hole to go pop but afterwards that's really boring so this was a picture I thought of being rather depressed by thinking that's that's our that fate you see the fate of all the interesting things happening ultimate fate is this unbelievably boring final state okay this is an emotional argument but it give me a bit of leeway okay so I began to think well it's not going to be us who are going to be bored because we're not gonna be around that the main things that'll be around will be photons and it's pretty hard to borrow Photon for two very good reasons one is it probably doesn't have conscious experiences not sure so but the other is more of a science point that that they don't measure time because a photon has no mass it travels at the speed of light and but the way relativity works it means that clocks stopped if you like so if it had experiences it but the moment of its creation would be one moment and the next moment would be infinity and so they just zip out to infinity without noticing a thing now you see I'd been doing work on this kind of thing thinking more about gravitation radiation and how you measure its energy and things like that and it was a very useful picture to squash down infinity a useful thing to think about here if you've seen these pictures by the Dutch artist MC Escher mmm yes and there are those which are called circle limits and there's a very famous one with angels and devils interlocking and they get all crowded up down to the edge they what you've got to think about is that this is a kind of geometry called hyperbolic geometry and the angels and devils live in that geometry and the ones right close to the edge think they're the same size and same shape as the ones in the middle oh you got it good yeah and so the idea is that if you look at it from the angels and devils point of view that's infinity that boundary but from our point of view we can look at it and we have what's called a conformal map that picture is a conformal map what that means is that little shapes are quite consistently drawn but there can be big or small and you don't care about whether there be or this more as small shapes are accurate or angles if you like a correctly drawn so it's what's called a conformal map and that conformal map describes infinity now you can do the same thing to the universe but I said do it um you can imagine hitting them with this remote future you can squash it down just like in the Escher picture to a finite boundary and as far as the things with no mass they don't have a way of measuring how big or small it is the Maxwell equations don't know the scale they don't care it's that work just as well for small as for big and you can stretch it in some place and squash it somewhere else as long as the stretching and squashing is isotropic so just as much one way as the other way which means more or less that you keep what I call the light cones there let's not go into details here but it means that that if you have things without mass than most particularly the photons then that boundary is just like anywhere else and the photons go zipping up to it and so you might think they gotta have somewhere to go okay well that's a you don't have to think that but that was the point of view I had the photons need to need some way to enter in a way but then where does it go but then there's the other picture which is the opposite then there's the Big Bang now you can do a similar sort of trick there which is stretching it out and making it into a boundary and that can be done too I played around with these ideas for a long time and the standard cosmology models you can do it with but the more complicated cosmology models you might have one which is very complicated Big Bang the general ones don't look like that at all so you need a condition which tells you that the Big Bang was the very special kind that it was it's all tied up with this thing called the second law of thermodynamics and there's all ties together with physics in a way which perhaps we don't have time to talk about but it seemed to me a really good idea to have the condition on the Big Bang that you could continue it in the same way I should say the idea of doing this was a former student of mine Paul Todd who's colleague of mine and he used this as continuing form or continuation as a nice way of saying what the condition is on the Big Bang to give you what you want but that's a huge condition but if nevertheless it's what starts our universe off in in a very special state which is what we live off in a way it's the second law of thermo exceeds that to get going anyway I don't know if you want to worry about that but anyway the point was that it looks as though it's a good condition on the Big Bang but it also should be conformally I like a boundary which if you had no mass you wouldn't notice it okay you've got particles with mass running around near the Big Bang but as you get closer and closer and closer the energy goes up the temperature goes zooming zooming up they're zipping around at such a speed that the energy of their motion is much bigger than the equals mc-squared mass Einstein's mass the energy in in the mass is a certain amount but when they get so hot you forget about the mass so they like photons behave like particles without mass and so they're just interested in the conformal geometry so the crazy idea I had not just only stretch out the Big Bang you squashed on the Infinity but maybe our Big Bang was a squash down infinity of a previous Eon so I'm saying Ariane began with a big bang ended up with this exponential expansion there was another one before us there will be another one after us there was another one before that and so on so it's an infinite cycle of Big Bang that's the picture and constant expansion to the point where there's no more energy and then somehow or another a Big Bang comes out of that yes that's right well that's the tricky part that people have trouble with it's universally accepted that the Big Bang was an event there's no pretty well unique theories that are attractive I would say nothing terribly popular there are certain ideas which say you can continue into the before the Big Bang Paul Steinhardt and what do they think that was it's it's has things in common with my model but it's not quite the same and you see it still you see there wasn't it right not long after Einstein produces theory and this Alexander Friedmann who was a Russian mathematical physicist and he produced the first cousin cosmology models and one of these was a one which has sort of bounces and Big Bang is expands out and then it contracts again during the bounces and so that was the one of his models the only trouble is if you put irregularities into these models you get black holes and these black holes could Palmer Crooker I mean incredible mess at the end and that doesn't join on to a nice smooth Big Bang the next one so you have trouble with those models but still people take these things seriously and then I say Steinhardt and to archive a model which is like that so these are things were nice to think about my own view is that they don't take into account the the black hole problem which is that my one gets rid of that because the black hole's all evaporate away by Hawking evaporation and so it forms a model I used to give talks about this feeling quite happy nobody would ever prove it wrong so I can go on talking about it but I wasn't quite happy with that I thought maybe you could see signals coming through so I had one idea about that but more recently and this is only just this year I have two polish colleagues that's Christoph Meisner and Pavan NeuroSky and there is a Korean who works in New York called Daniel Ann and we the four of us have a paper which I think today or tomorrow will be the new improved version of his paper should be on the archive and this the title of the paper is are we seeing Hawking points in the CMB sky now what's a Hawking point you see I talked about the black holes sitting the previous Eon to our us assuming it's more or less like ours there will be black holes in clusters of galaxies huge enormous ones swallowing up pretty pretty well the whole cluster and what happens to the energy in those black holes well it goes out in Hawking radiation it takes an age ages and ages and ages maybe 10 to 100 year gogol years or something ages and ages but all that energy in the picture comes out basically in one point think of that as a picture and right at the very edge you see there are not a lot of angels and devils squashed together there so that the entire radiation from that single black hole will be squashed into that little point now we're on the other side what do we see well there will be a big release of energy at that point and that's what we call the Hawking point and it spreads out you see what we see in the Cosmic Microwave Background this is radiation coming from all directions and this radiation doesn't come from the Big Bang exactly it comes from 380,000 years after the Big Bang so there's a sort of last scattering surface where photons which are trying to get out finally finally can escape and we see them now that spread out from the Hawking point to what you see in the in a cosmic microwave background in the last scattering surface is something of the diameter of about eight times the diameter of the moon no bigger no smaller now you wouldn't see the whole thing because our past cone where we what we see cut across it we don't see the whole thing but we see probably most of it so you could imagine something from about four to eight times the moon's diameter which is a small region which is highly energetic more energetic in the middle and tapers off as you go to the edge and we seem to see these things the analysis that but the polls they have the techniques and the actual analyzing the data this is the Planck satellite data whose done by Daniel an and then we look at the data and we seem to see an effect which see what you do is you we've got only one universe that's what they're complaining about so how do you know if something's real or not where you make zillions of fake universes and you compare this with them there's a lot of technique about how you do this but Daniel first did a thousand of these fakes and they were sort of two sizes of these you look at these rings to see whether the temperature goes out from the outside to the middle and there were two sizes both within this size that I'd say about four degrees across the sky and there was no evidence of them at all in the simulation so this is a real effect okay then people were skeptical of this for one reason or another so Daniel did another well 10,000 altogether and you occasionally there one or two which do what two or three to be precise where you see this effect in the simulations but if you work out the probability that this is a real effect you come up with a confidence level of 99.98% that this is a real effect so we're waiting to see what people say about this

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Id: Mz1DAzYS9Kk

Length: 22min 1sec (1321 seconds)

Published: Tue Dec 18 2018