The Next Universe | Full Talk | Roger Penrose

Well, thank you very much for inviting me and I want to describe an idea that, well, is not that new because it is about 15 years old, but I suppose it counts as new. I want to

talk

about something that I say happened before the Great War. Bang now you see this represents a change of mentality on my part that I used to think like Stephen Hawking in many people that the Big Bang had no before because the notion of before and after meant nothing when there was none. a

universe

around and that's why you couldn't even

talk

about before, well, I'm going to come back to that and claim that there is something before, but before I get to that, let me describe the

universe

, this is an image that more or less describes the history. of the universe as we understand it.

I need to explain a couple of things about this image. Well, first of all, time is going up and the Big Bang is down there and it expands, it slows down a little bit and then it starts doing this. tx what they call the accelerated expansion that seems to be taking place although there was some dispute about it in the previous discussions I was involved in, but I am considering the visit is doing this accelerated expansion now, a couple of things about this image. I just want to show you that you can take sections that represent a moment in time if you want.

We imagine that blue plane sliding upward and the universe at any moment is considered to be that intersection. Warning: It looks like a line instead of three-dimensional. space, you have to make allowances, add a couple of dimensions to get the right image, so this is really three dimensions and one times, so that's the first thing I want to explain about the image, the second thing is what it's all about this. The frilly things on the back are fine, that's there because I don't want to prejudge the issue of whether the universe is spatially open or closed.

These are beautiful photographs that were due to MC Escher, the Dutch artist, and here we have the closed one. You see, you imagine space as the surface of that again. Now you have to rule out two dimensions, so one dimension because it's actually a three-dimensional version of that. That is the near case where the curvature is positive. This is the flat case where it is. Euclidean and this is the case that is called negative curvature. I want to come back to this image later because it's a particular representation of this geometry that's called hyperbolic geometry where these angels and demons, I mean, Escher very cleverly uses the same creatures to illustrate these three completely different geometries, now the current view is which is more or less flat but of course that means we don't really know because we haven't seen everything, it could curve or it could do this.

I'm not going to worry about the ruffles in the back is just to say that I don't care which one it is and I don't care what happens in the back because at least in this discussion I do care to some extent, but that It is not like this. The point now, the

next

question is what is all this in the beginning? I have this thing called inflation. Now, if you look at any modern cosmology book, whether popular or technical, they talk in the first ten to minus thirty-two seconds. that means one over a fraction of a second, that is, something like thirty-two digits long, a ridiculously small fraction of a second that the universe was supposed to have inflated.

Now, to give you an idea of ​​what inflation looks like, I'm putting up a mighty mountain. magnifying glass here to take a good look and what do we see I should point out that we don't see that is the handle of the magnifying glass but what you see is something very similar let's go back to what you see in the future written So it's kind of a model of what's happening there , but hidden at the beginning. Now you see the reason why I didn't want to mention it here. There are two reasons, one is of course that it could be hidden there and that's why we need the magnifying glass. glass, the other reason is that I don't really believe it, so this puts me in a bad minority, but I'm already in a minority, so that doesn't matter too much, so I'm trying to say that I don't believe in this, but there good reasons to believe them, let me first say what the limits are.

One of the reasons that people bring up is that you want to explain the curious fact that the universe is actually very, very uniform and this was one of the explanations that somehow if it was very irregular then this inflationary phase will make everything longer now never I believed that argument and the kind of reason is this imagine the universe was collapsing so time doesn't keep going up but then there will be all kinds of wrinkles There will be black holes and this image doesn't now. I want to use another image but I couldn't find it as good.

Don't you have to imagine that it's a very, very complicated thing up there that doesn't look like that? A neat little spot, but a big mess up there, that's the kind of thing that happens when the black holes that you see this fall will form black holes and freeze and make a big mess and it would look horrible if it didn't. So why was it like this? Isn't that the other way around? You see that Einstein's equations work equally well over time one way or another. Why wasn't it that big mess at the beginning? An inflation does not solve that equation but I want to talk about it because this is a key point of the argument and for the moment I am not going to say why I am only going to say what in a certain sense and to do that it is useful Return to the Escher image that I just showed you and now this is a spatial image, there is no time in it, so it is a space, but these angels and demons inhabit this infinite universe, although it seems to us that they are getting smaller and smaller. to the edge you have to imagine but you can choose the devil's angel however you prefer you are the same size no matter how close to the edge you are so these guys or fellow asses no matter where you are you will see what it looks like Just like the beginning and the transformation involved here, is what's called conformal, that is, you squish in all directions by the same amount, so not only are you scratching this way, but you're squishing it by the same amount, it's a very kind of pleasant. from geometry the angles like the angle on this devil's wing will be the same no matter how close to the edge you are the eyes will be the same shape you know how close to the edge they are just a different size so which is a very beautiful type of geometry, well, you're not interested in distances, but you are interested in shapes, small shapes, so if you like angles, this is a very crucial part of the argument that I want to present here.

These angels are demons because, from their point of view, the universe is completely infinite, we look at it from a different perspective, we allow ourselves to crush the infinite in this conforming way and you can imagine yourself taking a step from here to there, they can't. do it, but you can imagine that something could do that, so let's get to that, okay, now I've applied this to the universe. This was the smallest drawn image now in the history of the universe that continues to infinity, but that infinity. like in the image of angels and demons, it was crushed to this limit here, which represents the infinity of this universe and that is something quite accepted.

You can make the universe, as far as we understand it, in the very distant future flatten out somehow. What it allows us is a very general theorem, there is a theorem due to a German Friedrich Hull, who established that in very general circumstances you can do this conformal crushing, so there is no discussion, what I am doing here at the beginning is what opposite. I'm stretching the big bang to make it look like a nice smooth surface. That's not something that usually happens, it just happens when the universe starts off very, very regularly and smoothly the way we seem to see it and there's one thing.

I used to call the vile curvature hypothesis, nothing bothered to explain what that means because it's a bit technical and my former students and colleague Paul Todd, who had another way of saying it, what does it say? The beginning of the universe is conformably nice and smooth, so you can do this, that's a hypothesis, if you take that hypothesis, you get this universe which is kind of smooth in the way we see it and it's very important for this thing called the second law of thermodynamics, the second law of thermodynamics says that this thing called entropy that increases as you go as time increases and the thing is that we see in the observational universe ii, but it seems that the entropy is very, very high at the beginning, which should be very low because it has to start low, what is it like?

It's low, it has low gravity, which means the universe with me. I really don't want to get into that discussion. I shouldn't even start early because it's key to the description, but it will distract me too much from what I want. I'm just saying there's a good reason to say this can be stretched it's very cute it solves a lot of problems if that's the way the universe for some reason stretched like this what's the reason well here's what I'm saying the reason This It's because this is our universe as we think of it, starting with the Big Bang and ending with this eternal exponential expansion that goes on and on and gets more and more boring as time goes by and the argument is that our universes a Those of us who serve We think that it is not the whole story that this future remember that Escher's image can be stretched and crushed and now it becomes the Big Bang of the

next

day and this is what I call cyclical cosmology according to the consort that we are here there was one of In these eons I call neo and looked in the dictionary to make sure that an eon was not a real period of time.

It seems wrong, it's a long time but not a defined period of time, which is fine. I, so I have used that term here, a cosmic Aeon is that, but I am stating that there was a cosmic aeon that preceded us, one after the last one before, etc., and they continue indefinitely. Now, you see, you might say, well, that's a little hard to swallow and that's what a lot of people say is hard to swallow because isn't the distant future very different from a Big Bang? Well, first of all, it's very, very rarefied, it becomes very, low and low density, it's extremely cold.

The temperature goes down and down and down. What is the big bang? The density of light is enormous, the temperature is enormous, but you see when you do this transformation that the one I did with the angels and demons who were satisfied was to crush or stretch, it gives a great point when you stretch it, then the great temperatures drop and the Densities go down when you crush it, temperatures go up and densities go up and coincide, so they coincide physically and also geometrically. Now there's a little downside to all of this that has to do with, well, we'll get to that in a minute before we get to that, let me talk about black holes.

I mentioned them before. This is an image of a black hole. It is not normal to see a black spot in the middle of something. a space-time image, so we have time going up there and this is matter collapsing and this thing here is the horizon, so I have time in one dimension and I managed to get a kind of two-dimensional space in gray, there is another , but only Stive had two when imagining himself going around and around like that and that's the image of a black hole. It's a pretty good image, actually. Now the point of the image is these cones.

Now one of those cones. I have to talk about the cones. What is really important now is what is called a light cone or a null cone. You have to imagine yourself in four-dimensional space-time. At any point there is one of these cones there. What does that cone tell you? Tells you what? the light does it, you imagine that there is a flash of light at that point and it is time that advances, extends. This is a special image. Now I can get all the dimensions if you want here. I have to imagine the cone. It has another dimension, but you think. of it as a surface, but these sections through the cone represent the story of a flash of light in the middle that expands and expands, so we have the red and then the blue and the red represents this section for the cone and the blue. one in that section and here we can have the two dimensions of the surface, so it's three-dimensional together and here we have just one, so it's a good image of what a cone of light does, so a flash of light is would extend and you.

We would have to imagine special terms in which things that extend like a flash of light would do what happens to the passing comb. Well, you imagine a flash of light entering and converging on that point. It's a very useful concept in space-time because it tells you causality, you see that things that can affect other things are always inside or on the cone and outside, you can't influence that, so this is it and this is relativity. special where all these cones are evenly arranged. This is general relativity where they can wobble. In various ways and the image of the jet, this is a kind of illustration of what can happen in the general activity.

The cones are not there uniformly, but you can see that the information inside cannot escape because it would have to cross the cone and stay inside. you can't do the cone because the cones point inward, that's why light and any type of matter is trapped within this horizon, so you can understand these things very well by looking at that image and thinking a lot about it and here is the materialyou look at the energy spectrum, you look at all these random fake skies and 4,000 fake guys that find zero, I mean, all these other numbers are that kind of thing. you find rings that are the wrong shape and size for that signal, when you hit it you see that none of the false skies show this phenomenon, which means that it is really significant this is even quite significant the number is quite small here any kind of good That's right, it's here, it's about six, isn't it okay? after you saw the evidence and then the problem but it's like that Daniel did it again 9,000 more simulations what happened to these zeros when this woman gets to this one it becomes ridiculously smaller than anything else it's a real thing what in terms of probabilities What does it mean that the chance of this being a random effect is that the chancery is real rather than random, there is 99.98% confidence, that's what you get from these figures, so it's really there and It seems to be there and what else can happen?

You explain well, I think that's the end of me, yeah, let's not get into that. I don't have time to go into that, but if people want to ask me, that's fine, thank you very much.