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Dick Bond on Multiverses, Hubble Tension, and Dark Matter
February 1, 2023
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My name is Dick Bond. I'm at the Canadian Institute for Theoretical Astrophysics, which is based at the University of Toronto, but it is flung across all of Canada under the guise of CETA, Canadian Institute for Theoretical Astrophysics. I'm a theoretical astrophysicist, a cosmologist, first and foremost a theoretical physicist. I've been thinking about these universal matters.
When did you become first interested in physics and astronomy? Probably birth? No, I would say...
Something that had an impact on me was a book that emerged in the early 50s, not that I was reading in the early 50s, but it was called, I think, 123 Infinity, which is a nice by George Gamoff, who was sort of Mr. Big Bang, although Hoyle named it,
And what was so compelling about it is that he was trying to take the information they had then on the universe and on formation of Earth geology and all that and life for that matter. And he tried to make a synthesis of going from basically the beginning through to the evolution of life on Earth. This is one book.
And it was amazing, amazing that human thought could try and
capture this. Of course we have gone a large distance from the information he had back then, but on the other hand he was a very smart guy and this was pretty compelling and I'm not the only one. I was talking to somebody at NYU, a great professor there, and it seems that she of the same era as me had the same
At one point I wanted to be a writer, and then I said,
You can't write without knowing what the leading edge of human thought is on reality if you like.
anybody who's writing without being there is writing something which will maybe will have things like emotional truth and other such things but it cannot be a correct statement not that what the students are reading now are correct anyway so what i did is i sort of shot my bow from that period
And the arc of my career has been exactly the attempt to do this kind of full integration of thinking and trying to take science, which means knowledge, and apply it to
The thing that really matters to me, which is the eye, that is to say the science is the way to try and comprehend one's self and the place in the universe, which is not an easy thing to do and most people have minds that are split into a lot of channels and many of the channels don't talk to each other, but a goal ultimately is to integrate and now that I'm of an age,
Do you believe that science is the cutting edge?
The modus operandi for humans to
Understand and see the universe and that it was the great development. I mean I can go back to Definitely the Greeks the pre Greeks through the whole Period of the Renaissance and in particular there is that period that is called the age of reason We have now entered into the age of unreason in the world around us although everything is trying to
Unify with everybody communicating with information and the information flood is kind of overwhelming and it does split into streams and we see this manifested all around us.
But what should be at the core is the basic quest for knowledge, which is the quest for science. So science is then transcending just physics or chemistry or biology. It is at the heart of humanity and how people should be operating. That is to say you want knowledge and you want to apply knowledge to the world around us. What's meant by the term universe?
Well, that's an interesting question because what is often put out there is the word which I am not that fond of, although many of my friends like to use it, the multiverse. There is only universe. That's what the uni is in front. It's the one. And then the question is, how complex is it? But it is all that there is basically by definition. The thing that is very humbling, if you like,
The universe seems vast, the part that we can see, but the way we think of it now is that what we see is only a tiny part of a much, much greater whole. Then the question is, is it all connected or are there disconnected elements? Well, if it is a completely disconnected element, we could never know about it because there's no communication.
The things that are beyond the speed of light reach, we don't get information on. The only way we can get that information is by looking around us in the universe, try to understand how the patterns have developed and then say,
I'll go back to 123 infinity. You then say that this applies to the regions that you cannot see. That, of course, is impossible to get right, really.
But on the other hand, it is clear that the themes that we see around us and out to the observable edge of the universe, there is a commonality. I mean, that is an amazing thing, right? That, you know, you don't go into some area of the universe, which is drastically different. I mean, in time, it's different because it evolves, but
It isn't like, at least in the patch that we can see, that there is a coherence. The coherence is essential basically, but for me, I don't really see why there should be coherence.
I mean, coherence writ really large, that is to say everything connected. In fact, one of the things that I'm known for is of label the cosmic web, which of course web means something to everybody because of the internet web. But what
That word or those words cosmic web indicate is the interconnectivity of everything and that every aspect of the universe is connected with every other that sort of
cliche and obvious, but it's also incredibly profound. It means that everything is dressed in the interactions with everything else. And in particular, it's writ large in the universe that we can see. But for me, the universe is beyond that.
And one way you can think about this is I don't want to get into the concept of the universe of simulation, although that's an interesting point. But in a sense, we think of the universe as a realization of reality. And then
We think there can be a lot of realities and at some level quantum mechanics
has those realities interacting with each other because the quantum theory is one of its basic elements is that information diffuses which means that you don't you cannot over concentrate information so it flows out I mean that's a manifestation of that as things like the hydrogen atom etc where
You don't have the electric charge rate at the center on top of the proton. The uncertainty aspects of the universe enforce through this kind of interaction that it's got a ground state. I may be going too far here, but it's got a ground state structure.
and you know that's manifested everywhere that there are these structures that occur and one aspect of the structure is information trying to propagate from whatever the origin is to throughout the universe. I mean that's sort of one of the main themes that I work on in what I do research on. That was a long way from what is universe
But in fact it isn't, because it's in my view at the heart of the universe. Regarding complex structure, how does it arise? You know, we have a mantra, and the mantra has been in place from, well actually you could really trace it to around 1980 or so, but maybe even a bit before.
but not well formed then, which is that there is something fundamental which we believe is happening all around us. Something that we work with all of the time. Everything is built upon it. We call it the vacuum, which sounds like it's nothing, but in fact the vacuum is like everything.
And that'll probably become clear as I say more. But within the vacuum, there are these fluctuations are often called virtual fluctuations. What does it mean to be virtual? It means that humans aren't seeing it. But if you take the vacuum,
and fend it then you get observable consequences and one of the observable consequences is all of the structure in the universe or at least that's the current picture and so uh and it's a picture which is so compelling it's one of the reasons i put so much energy into trying understand the concept of deformed vacua which is so anyway the basic picture and
These fluctuations are happening all around us and you know at some level all of your structures Yourself is built upon that underlying structure of this what you might call vast sea of fluctuations that exists and that all of Phenomenal reality is played on top of that Hugh it's like a huge sea and here we're sort of you know, I
Sailing along the surface of that sea and we don't know how deep the sea is. We don't know how far the vacuum goes It may go I doubt anything goes to infinity but it could and so the
Anyway, so the vacuum is fundamental fluctuations that are like virtual, I mean people think of it as virtual particles. So you think of charges like plus and minus, plus and minus always appearing, but that they don't actually break apart from each other so that you actually can observe in your detector a plus or a minus. They're kind of always oscillating and blending, but the same
aspect is that that's kind of a so-called fermion picture where there's uh well i i actually don't
Want to get heavily, unless we go there eventually, into fermions and bosons? We probably will, but maybe not at this point in the conversation. Anyway, the basic mantra is quantum fluctuations, but that isn't the important issue. That they exist is fundamental. That they condense and freeze out
and freeze in patterns of density, fluctuations, gravitational potential fluctuations. Those things are what ultimately grows to make all of the complex structure of the universe. So we have what is in effect a relatively
Simple theory. I mean, it's ridiculous that we think we can think about it, which is, you know, the first 10 to the minus 33 seconds of the universe and all of that, but we do
and it just seems like home those thoughts right and that consequences are everything and we actually think we can observe them through the impact on things like the cosmic microwave background the photon afterglow the big bang and and many other things so we have a a theory where we can make observations here and now on earth in the large scale structure of the universe
and interpret what we think is going on at these unimaginably early times and part of that is because what was happening at those unimaginably early times at least in the region that we can see seems to have been relatively simple. We're looking for
more complexity in what emerged from the Ultra-Early Universe because that would give us more information. But right at the moment, the amount of information we're getting is we're essentially compressing all of the information in the Ultra-Early Universe into what is in effect two numbers. It's hard to believe, but that's the story. I mean, that is the general point about structure formation. Then
As the universe evolves, species emerge. I'm not unlike in evolution, biological evolution, so there may be some kind of grand unification soup, which I think is probably correct, inflationary energy, and I know you want to get to this eventually, that is to say what is called dark energy, that that's like this kind of universal coherent
energy that splits up into what is ultimately all of the species of the universe and then it and then the universe passes through various epochs where certain of those species are more important than in other times. Species come and species go and we're dealing with some kind of fossil relic which is a non-trivial one because it's what makes us up.
Can you explain how the universe expands and what's meant by it? Contrary to popular view, it's true that on large scales the universe around us is expanding, but it is not expanding here in this room. It's in effectively a state of equilibrium.
And so when galaxies and other such things form, there is no expansion associated with that. This is a good thing, otherwise we would all be getting fatter because of the universal expansion.
On the large scales, very large scales, there's an expansion. The expansion is characterized by a rate of expansion. It's called the Hubble parameter. I'm sure you've heard of it, which is basically just the expansion rate of the universe. But you can also think of it as spatially dependent. And so in our region of the universe, our galaxy here, there is effectively
The Dynamical Universe
And now I'm losing the thread of where we were trying to go basically because I was going someplace. I was trying to give you a way of looking at the universe that is actually not standard. But if I'm to look around me, which if I can, I will. This is a, uh,
Undergraduate student is working with me. This is density against time showing the thermal history of the universe as it starts at the beginning and goes through various phases. I know you're going to ask this question later, but I thought, thanks for arranging my prop.
And here were four points about what we were going to do. She's still engaged with this with me. And one of them is the H naught tension, which has gotten a lot of press recently because from the cosmic microwave background, which is this really high precision thing that I've been very much engaged with throughout my entire career, uh, we get a certain value of how rapidly on large scales the universe is expanding on average.
And then there are other claims using things like supernova and stars of a specific form that the value is different in the quite general cosmic neighborhood around us. This is called the H naught tension, the expansion rate tension. And it's the number of meetings about this is enormous around the world.
And the issue is whether it's a systematic effect of not understanding the data well enough or whether there is some new profound thing associated with something that happened relatively late that caused this expansion to change. We already know that the expansion is changing. In fact, that was part of the great discovery of what's called the dark energy.
But it may be that there is a different expansion in the area around us. Razor blades are like diving boards. The longer the board, the more the wobble, the more the wobble, the more nicks, cuts, scrapes. A bad shave isn't a blade problem. It's an extension problem. Henson is a family owned aerospace parts manufacturer that's made parts for the International Space Station and the Mars Rover.
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If you use that code, you'll get two years worth of blades for free. Just make sure to add them to the cart. Plus 100 free blades when you head to H E N S O N S H A V I N G dot com slash everything and use the code everything. Out to a fairly large distance and then on even larger distances. So this is a puzzle. And why did I do this? I was just trying to say that
there is a simple way of thinking about the evolution of the universe as long as you add position as well as time into how you think about it and that it's inhomogeneous and that it's the same basic language but it is rarely used that way in the subject which one of my missions even with undergraduates is to teach that way of looking at things
What is dark energy? Dark energy, well it emerged as so-called Einstein's cosmological constant and back in 1917 or so,
The observations were such that there was no indication, A, that there was clearly external galaxies. And so it seemed like the stars and structure, they were just buzzing around us. So that on average, it was an equilibrium situation. And so yet when you take the laws of gravity, Einstein's theory, curiously enough, it would either contract or expand.
Automatically the contraction is called gravitational instability and it's the way we understand how structure formed in the universe. It's the gravitational instability theory of the formation of structure. And so he said, well, you know, maybe the data is going to enforce me. So I'm going to put in a term.
which the theory allowed and it's called the cosmological constant and then about a decade later or so somebody proved that that theory is unstable as well and Hubble discovered the expansion of the universe by looking at galaxies nearby and how they were moving away and you know this famous statement
Einstein's that it was the biggest blunder. He never apparently actually said that and it wasn't a blunder. It's at sort of the heart of much of our thinking because one way of thinking about it is that it's the energy density of the vacuum and I'm going back to the word vacuum. So when I write it,
I often use rho as density, many people use rho for density, sub-vac, as if that's an obvious thing, vacuum energy, except that, as I said earlier in this, in this brief thought flow, is that
The vacuum is fundamentally deformed. It's deformed by the expansion of the universe. It's deformed by structures in the universe. So vacuum is not actually this pristine thing that people think about anyway. The bottom line is that that was the original lambda and it was embraced by, well I won't go into the full history of this, but it
would rise up and go down and rise up and go down in terms of its stock, if you like, about whether people were interested in it. It kind of got resurrected for a few reasons around the mid 80s. And that's when I was, I thought it was a, you know, a great idea. Why? Because, uh,
As well as matter and radiation, the universe can have curvature. I mean, in fact, it's always got curvature on small scales. That's what causes the matter to concentrate. Anyway, the basic point is that there was this first indication for me that you needed something akin to a lambda. The reason of going back to the thread of thought there,
Curving the universe on average on large scales and yet having small fluctuations on smaller scales and we had evidence for that Anyway, the basic point is you have to have this large-scale curvature if you're going to have what is called an open or closed universe whether it's curved up like a sphere or curved down like a saddle and
That was, you know, what people mostly thought about. Whereas the vacuum energy density is something that's constant and scale independent, or at least that's the view. So then the other dilemma occurred. Well, how can it be as small as it would need to be to make a universe like ours? And that continues to be a huge mystery. Because if you count
The amount of energy density that you think is in the vacuum, it would depend upon the Planck energy scale. In fact, it would go like the fourth power, which is a huge, huge number, like nothing that we have ever seen, except the key element here is that you don't apparently get to observe that. You only get to observe differences or changes. And so maybe it can all be well understood that way.
But anyway, so I liked Lambda. I liked it as a extension beyond just dark matter and burials, which are the stuff that we're made of. And so it became part of my kind of standard thing.
And then we were dealing with two kinds of data. Cosmic microwave background as it was emerging, fluctuations that emerged from the universe around 380,000 years after the so-called Big Bang. And that's like 13.8 million years ago. So that was giving us valuable information. It's since filled in
brilliantly, but, you know, as it emerged, it was giving us an indication, but you had to, we had to add large scale structure to that, the spatial inhomogeneity on large scales of the universe, in order to say, it looks like lambda is pretty good. And we did.
And then, so that was microwave background and large-scale structure observations. Then another set of groups, they were looking at supernova and they were developing something, curiously enough, it's called the Hubble diagram, where it's Hubble parameter as a function of time and
If you have an ordinary universe without any lambda it would have a certain shape and with lambda it has a different shape. And so after some stops and starts it emerged that that looked like it was also indicating accelerated expansion and that's the one that sort of
became the popular way of understanding about this emerged. But the microwave background and large-scale structure were right there as the underpinning of this whole story. And then there was another experiment that I was involved in that was called Boomerang.
It was a microwave background experiment called Boomerang because you launch from the Antarctica and the prevailing winds at the top of the atmosphere caused the balloon to go around and around and around and so you get lots of data. And it was really the thing that sold the vast community, in particular the particle theorists, on that you have to take this extremely seriously. It's like
that that's clearly the answer. Then the issue is, what is the nature of this so-called dark energy? I mean, what does it mean to say an energy is dark? For that matter, this is a bit of a joke. For that matter, why do we call it dark matter? And why, since matter and energy are intimately related,
Why do we have this stupid label? But we do that in this subject. There are stupid labels all over the place. Some actually quite clever, but you know, up down strange charm is
is particle theory right so you know there's a little windsy that does occur but dark energy really doesn't convey the information it's actually a potential energy density that at the moment we observe only through its impact on the expansion of the universe and not in any direct experimental way the whole
is that we will be able to. And so, you know, billions of dollars actually have been put into experiments that give huge amounts of astronomical information. But one of their primary raison d'etres was to learn more about the dark energy, which you cannot learn from observations on the Earth in the lab.
it is really something writ large in the ultra-large-scale dynamics in the universe. Anyway, it emerged as being an ingredient, and as time went on, it got, the observational evidence got stronger and stronger and stronger that that was it.
And so there were two aspects to this. One is, is it just a uniform potential energy density so that everywhere, including in this row, there would be this uniform energy density that's sitting there. You wouldn't really be feeling it, but if it could, it wouldn't try and expand you. It's just that the other forces are so strong that that doesn't happen.
So there's this kind of uniform energy density that we think is all pervasive, but the evidence we have for it is on very large scales. So then the question is, does it change in time?
And why is that interesting? It's because it says it might not just be potential energy, it might also have a kinetic component. You know, there are two types when you learn physics in school, there is potential energy and kinetic energy. And so what is the kinetic energy amount of the dark associated with the dark energy? So this is a blazing question. And as I said,
We're trying very hard to determine whether or not that's needed. At the moment, it isn't. And yet, some people say you'll never find it because it's uniform. It's got to be uniform. And I don't ascribe to that. I think that it can change. The thing that to my mind is the most interesting is if the dark energy
actually interacts with ordinary matter and dark matter so that it can have a spatial dependence, not a sharp spatial dependence, but a spatial dependence that can allow us to determine more about it because otherwise all we get is a number. What's the balance between matter and dark matter? You know, the fact is we have dark matter here in our galaxy holding it together
but we don't think that we have a very high concentration we do would have a concentration but not a very high concentration of dark matter in this room with this relative to the rest of everything else everything has its structural aspect and it's all describable in detail by
the laws of transport in the universe, something that I am very keen about because it's an issue of how does energy go from one place to another. And evolution is all associated with transport. And so
The transport of very unsordinary matter is different than the transport of dark matter and the transport of dark energy seems to be particularly simple, but hopefully not so simple that we can't learn more about it than just a single number.
And so all of this is in this mix or this soup of ingredients. And I think this is one of the points you want to get to later. So jump into it now and actually go back to my prop here, which is the history of the universe, the so-called thermal history of the universe, starting with
This very high density, which is the inflationary epoch, the idea is that it was fluctuation this year that ultimately led to structure.
then there is a point at which that incredible coherence breaks up. A colleague who's actually just in the office next door and I, we coined the phrase a shock in time, so that you have this universal accelerated expansion, which is the dark energy of its time, alter the universe, but then it kind of shatter isn't the word, but it
shocks and becomes all of these kind of fluctuations like photons and electrons and positrons and all of the normal quarks and hadrons and other things that have to arise from our, you know, our observations show it, our existence shows it.
And that is a period in which the density changes. That's a period in which radiation dominates. And there are a number of epochs that are associated with that. There is the so-called Hadronic era, which is the period where you haven't formed
that it's primarily a quark-gluon plasma, which means that the quarks haven't really, you know, completely gone into neutrons and protons, and then you have all of these, which later become mesons, all of these so-called gluons, which are the glue that holds them together, and the gluons and the quarks
They are all relativistic and have this large density. See, I'm speaking as if this is an absolutely obvious stated, you know, from above we had these tablets and that is not true. Everything that one thinks about the elderly universe, you know, there could be the rug pulled up from under us or maybe a different way of thinking about it, but
The evidence is amazing for the story of cosmic evolution. So we have gone through to the quark era, but then the quarks and gluons, but then they basically freeze out first into one that's dominated by mesons as well as neutrons and protons. But the neutrons and protons are sort of
small ingredients relative to the total. I know you want to get to this question as well. So we'll get there. Don't worry. It's nice that I have my prop though. And there is a period in which you transition from basically free quarks and gluons that are all in some what's called a plasma
not unlike the plasmas that we're used to with the electrons and ions, etc. And then it becomes hadronic, which means that because of the expansion of the universe, you've moved things far enough apart that forces caused
Basically a spectrum of mesons with different masses to form.
Ultimately, as the universe continues to expand those annihilate, and at least behind the protons and the neutrons, there's still a huge amount and most of the energy is in electrons and protons and neutrinos and photons. And that is what is called the lepton era of the Big Bang, or at least used to be called that. I mean, to me, it's just a continuous situation. And that is the period that hear that sound,
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in which hydrogen and helium nuclei get the patterns they do. So it's called Big Bang Nucleosynthesis, for nuclear, and the reactions that occur create
the light elements. Mostly helium and hydrogen remains and so most of the universe is hydrogen and helium. There's some deuterium and you don't get very much
almost none carbon and oxygen and iron or anything like that that is delayed until the formation of stars and you forge those in the nuclear furnaces of the stars and then you have to explode things and blow them out so we're passing through these epics this thermal history and so we've gone through this dominance of relativistic particles
So here it was dominated by what was you might call it ultra early dark energy. Then we have this period of dominance by radiation and then
There is an epic, maybe a hundred thousand years after the Big Bang, where you begin to transition to the dominance of matter, which is non-relativistic. That's when the protons and the neutrons in the dark matter basically take over the dominant things in the expansion. And that's also
When the photons decouple, the word decoupling is something I may use later. As the universe expands, various things at various times decouple. An extremely important one is when the cosmic microwave background, the photon after glow, the big bang, basically stops strongly interacting with the electrons. And so they
can split apart and we observe the residue of that in the cosmic background radiation. Thank you for this prop as well. This was from the so-called Wilkinson Microwave Anisotropy Probe, the beach ball. It shows the tiny fluctuations in the microwave background from which we learn so much. And this is basically trying to be a snapshot
of the universe.
the Planck satellite. This was an early version of Planck as we were taking all of the stuff in front of it, and these are the fluctuations. Planck is still the best experiment and the best information, and I've been involved in that a long time, and it's the best indicator for lambda, the cosmological constant. Anyway, so that's this period.
of dominance by non-relativistic matter and with the photons having propagated up, that was essential for the structure to start collapsing and forming and allowing the ability for galaxies and ultimately planets to form. You had to get it out of the A, dominance by dark energy and B,
out of the dominance of radiation in order for a structure to have formed. So that's an extended period. And then in a well, depends how you rate this, but not so long ago in cosmic history, we now see that it's this expansion
is trying to go towards this uniform energy density which is the new form of the dark energy so it's a interesting thing that we begin with what is in effect dark energy theory which is the emergence of the universe and then we end up with a dark energy which is the late time behavior so dark energy dark energy now what is really curious
is that there is no grand unified theory between this and this, which is just egregious. But there are many egregious things in this diagram which I have not gotten into, not egregious, hints that we haven't folded into the full unfolding of the cosmic evolution story. For example, the passage from when it was dominated by radiation to when it was dominated by matter
happens to be relatively close in time to when the
electrons started to coalesce onto the protons and make hydrogen atoms so the universe passed from fully ionized plasma into a largely neutral medium and that, that those numbers are close to each other is weird and there's no explanation for that. Similarly there's no explanation, although people have tried of course, for why the
That amount of baryons, ordinary matter, is so closely tied to the amount of dark matter. There's sort of a factor of six in between them, but six in cosmological terms isn't very much. And so a full theory should be able to tell us exactly why that's so, and it can emerge
It's just that there is no solidified understanding of why that should be true. I think you want to mention wimps in the future. There was something called the wimp miracle, which does tend to give
by chance relationship between the two. But, you know, just, well, anyway, I can go on and on. So maybe you might want to redirect me into something else. I have just given you the full thermal evolutionary history of the universe and then a question that naturally comes to mind. What happened? It's a good prop. It was well arranged.
What happened before here? That's time zero. And what's going to happen out here, which is time infinity if there is such a thing?
And obviously, you know, we may have a lot of hubris, but not that much hubris. But the standard picture is that if it really is a potential energy dominated, then the expansion just continues exponentially. That doesn't mean that everything disappears. That's ordinary. It's just that everything is being
kind of not fully but somewhat torn apart by the dark energy which is trying to do an accelerated expansion so even things that are stable right now might not be stable I mean there are many reasons for the instability but then you know once upon a time fooled around with the theory in which this would go up like that
where the density goes up. And then it would go up to a point and start the whole cycle again, which is kind of a cyclical version of the universe, of which many people have played that game over time, and it's still popular in certain circles. But the main point is we don't know. It's really interesting physics if it's true.
but we don't have an indication really about you know what the long-term behavior is here so we can't really predict our future and what is I have my own ideas not that different from some other people's ideas on how we go from before times zero through to there is no time zero is the basic
answer it is that the expansion of the universe which is necessary the coherent expansion universe which is necessary to make the universe as we see it around us it emerges it emerges from some maybe it's you could call it a quantum soup or something with again fluctuations all over the place
Anyway, all of that is, of course, I mean, you have to be very careful here. What do you know? What do you think you know? And what's heavy speculation? There's a lot of fun in heavy speculation. And, you know, you can do some theorizing. And what we prize most, I'm a theorist, what we prize most is a
The detailed mathematical understanding of the kind of phenomenon that one's trying to explore, explore mentally, exploring it observationally, really, not these utterly ethics. I mean, you would like to find some signature of what happened at time before the Big Bang or whatever, and people have proposed those things to
These are highly speculative, great fun. And then the question is, when you get
The avalanche of papers, which constantly appear on these subjects, how much attention do you want to give to each one? Because, you know, a lot of it's whistling in the wind as well. Playing in the sandbox is maybe another way to say it. What does the Hubble tension indicate about the future of the universe? This issue of the Hubble tension, if it's physics
then it's saying that something different than what we think is going on. And there is some kind of passage that has occurred and the time of that passage would be later than when the current dark energy overtook the non relativistic dominance of the universe. And so that's, you know, obviously exciting.
if true, and the skepticism or worries that occur is that these observational campaigns are really difficult to get right. And one of the advantages paradoxically of the cosmic microwave background at 380,000 years is that it's relatively simple to understand
whereas once you're dealing with real astrophysics supernova and uh... sephi variable stars and things like this there are all sorts of effects that you may not be able to fully deal with theoretically and you just use as uh... well it looks like this is the trend so let's use that law and let's say that it's perfect everywhere uh... anyway so that's into the dark energy thing so it makes
I mean nominally the density on average is related to this Hubble parameter and so if the Hubble parameter is like 10% difference roughly speaking according to this Hubble tension
Then if you were really naive, you'd say, ah, something has happened to cause the H to go up. What is that? And so it would be a really profound implication for the universe at large if it turns out to be true. And we will get
the better and better experimental information on this. I mean, there's no question we have these change campaigns that are going on. Uh, the, uh, James Webb telescope, of course, is the thing that is most, uh, in the public mind, but the number of, uh, of experiments, the observations observatories in all wave meds that are covering
The sky is just enormous and it's a tribute to humans that they've decided that this is one of the places where our resources should be put into. And, you know, I believe in this strongly. I should because I'm an astronomer, but I believe in this strongly because it's going back to treating the universe in terms of the ideas of the age of reason, which is where we were at at the beginning, which is reasoned.
How can we reconcile the variance of dark matter? Anyway, but then you were asking about the issues of dark matter and what is it, and we know of it at the moment only through its effect on gravity. That doesn't mean that it's not dark matter or that other alternatives are reasonable.
I mean, we have a lot of really interesting evidence for it that has actually been around since the 1930s. It sort of picked up steam around the early 70s. And I'll just explain that for a second. So in the 30s, a very smart guy said, you know, if there wasn't something else, the lotion of
This is not too long after Hubble expansion. The velocities of the galaxies within clusters of galaxies, the thing would have fallen apart if there wasn't something extra, and this was the dark matter, the first indication.
Some colleagues very cleverly said, you know that a galaxy would be unstable
If there wasn't some kind of dark matter holding it together. So this was an issue of, you know, galaxies. A lot of them were in these spiral forms and those would be unstable. And so the invention was, oh, let's put a halo of something around it to stop this thing going unstable. And then the issue is, what is it?
Well, the original idea is let's be conventional. Let's just say that there's stars, but stars that are a bit difficult to see.
And, you know, I got into that game. We were especially interested in whether there could be a lot of black holes doing it. It's still possible that black holes could be the dominant source, but we were especially interested in black holes that might have come from an early generation of stars rather than from the ultra early universe. If they come from the ultra early universe, it's like other forms of dark matter. You might call them wimps, except that it would be they're called primordial black holes.
Anyway, there's that possibility. Then there was a period where neutrinos, well, neutrinos do have masses, but it was possible that their masses would be such that they could make the dark matter. And that was extremely exciting, but it made certain predictions, which turned out not to be true. It's still a component of dark matter, but not the dominant one.
and then as we explored it further we said okay well you know it can't be the neutrinos because they were created from the early universe moving too fast so let's deal with a colder variety and that's called cold dark matter and I had a lot of fun exploring all of those possibilities in the
early eighties, actually through to now. And, you know, then an issue is just like with the dark energy, but even more so, what are the interactions of this stuff? And that manifests itself in a few ways to create it and decouple it.
That requires interaction beyond gravity, and that would be early universe. And there are various things that can be dark matter that arise in the early universe. One of them is these weakly interacting massive particles. The weakly interacting, that's what neutrinos are, they're weakly interacting. It's just that the mass is a bit higher here than the neutrino masses, which is why they turn out to be cold.
But then there are other possibilities that there is this sort of more wave-like dark matter, just to give the term called axioms, that also were emerging at the time and that we folded into the possibilities for the cold dark matter.
So those were kind of the panoply of things that were on the table with a lot of work on the weakly interacting massive particles sort and the different theories that could give rise to them. And then the exciting issue was that if they have interactions, which they must have to have decoupled in the early universe, it means that those same interactions can manifest themselves around us.
And so huge expenditures have occurred to try and directly detect the dark matter, not just gravitationally, but in, for example,
Now that we're here in Canada, the Sudbury Neutrino Observatory in Sudbury, which is a very deep mine, has got a lot of experiments that are trying to detect the evidence for the dark matter if it's all around us coursing through the earth and making reactions that you can then infer the nature of dark matter.
The executive summary is that after all of this time, we still have the situation where dark matter has an uncertainty in its mass that's 60 orders of magnitude, at least. In other words, we still don't know
But that doesn't mean that dark matter isn't there. It is there. It's just a question of how do we actually detect it by non-gravitational means? Can you walk us through one of your academic adventures? It's more of how I approach things, which is early on I got enamored by the universe as a collective. I mean, it is, but
You know that it really got into me so that if you have a slab of matter, let's take this table as an example. And because I did a lot of my original research at the beginning on neutrinos, they're really weakly interacting. So you have neutrinos coming in, they do this little tickling.
And in order to get the response, you think of this entire table as a thing that's responding, even though, you know, we're used to thinking about point light phenomenon, but there is a whole collectivity of things. So that's point one. I love the collective and how, and that's the whole idea of the cosmic web, everything interconnected with everything else. But then the other great passion I have is for entropy.
And entropy, of course, it was a thermodynamic concept that was developed to understand heat engines and all of that. And people have been struggling with entropy for a very long time. And there is this guy, you may have heard of him, Shannon, who was interested in information flowing along channels.
And I'm going to tell this hear that sound.
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It was a great story. Von Neumann, who was the person that took
entropy and made it into something that was quantum mechanically compatible. Shannon asked, I have this thing, it's sort of like entropy. What should I call it? I said, just call it entropy. Nobody understands entropy. So my whole career has been trying to understand entropy, which I now think I sort of do.
In a way, I'm still struggling with a full, grand, unified vision of how it relates to everything. Now, why is this getting back into your other question? I can also, of course, expound upon specific
Whichever route you believe would be more appropriate to answer that question.
Well, I'm going to first of all, give a little anecdote. Theory of everything been around for quite a while. Of course, grand unified theory is what everybody's been striving for. So I was at a conference, many people, including Jim Peebles, Nobel Prize winner, were at a conference on Vancouver Island and playing Tarzan, I swung into
This will sound crazy, but I swung into a pond, hit my toe on a rock, and it broke, and so I had, you know, had to do some pain pills or something, but I had to still do my talks. So I decided to make this into a cosmic joke and said, I am now going to tell you about my theory of everything, the toe, because that's what it was, T-O-E, the toe, right?
And so I use the whole spiel to make a theory of the universe associated with my toe being broken and the search for solution and healing of the toe. Anyway, what is this to get across? It's to get across that if you don't have humor in dealing with the quest for toe, then you're not thinking about it right. People are
What role do higher dimensional manifolds play in structuring the universe? The more important thing than metric is the square root of metric. If you know what I mean, it is called in four dimensions called a fear mind. It is a field. It's a field with labels and the labels are
Energy. So it's like a gauge field and one of the parts of it is energy. Energy is in that case like a charge. So it then means that that quantity, the fear bind for energy is quite, quite analogous to the photon field, the electromagnetic field for charge. They're the same in structure and how they play out.
Momentum with the three dimensions that we now have of space, they each have their gauge field. They have their minds and they couple in exactly the same way as the photons, even more so they're coupling. It is more closely related to how the gluons that hold things together work.
So when people ask, and that was one of the questions which I think you were trying to get at, is gravity real? And I will tell you that if gravity is very, very similar to all of these other situations, the interesting thing is that you put energy together
with this fear mind, they couple together tightly and that makes action. And action is, if you look at any particle physics paper, the very first thing they do is they write down the action. The action is the thing that is coupling the forces of action and reaction together
and it causes the whole process to occur, not unlike yin and yang actually, but you know, one can riff off of these philosophical thoughts, but basically the structure of the universe seems to be that you have something akin to a charge and then the universe or the reservoir or whatever, or the vacuum is responding.
to the charge and the two are tightly coupled together. An interesting question from my perspective now is how tightly they're coupled together. But the main point is that they form this quantity together. So this concept of gravity being so different is, in my view, just people playing in the sandbox, but it's dirty sand or something. Is gravity an emergent property?
People have played with an attempt to make what is in effect a thermodynamic view. Whether thermodynamic or non-thermodynamics, it's the same thing. It's just that, I mean, again, it's kind of playing with ideas, but in my view, not looking at them as they are. You see, thermodynamics is not just, you know, temperature or something.
fundamental is change and so in any thermodynamic system of which this room is an example it's an open one but it's true
There are thermodynamic fluctuations all over, and there are gradients in the thermodynamic potentials that cause things to move, for example, from hot to cold. I mean, that's, you know, standard thing. That actually is the story of entropy, which is ultimately related to the story of action
which is also gradients associated with flowing from here to there. So the second derivative of these things is got all of the aspects or many of the aspects of curvature associated with it. And curvature is one way that we understand how gravity is operating. And so
What we're dealing with is an attempt to find a language. But the thing is all the languages are all ultimately going to tell us the same thing. It's just that if you hear something in different languages or with different words, you can get further insight. And then some people get locked into just a single language. It is great to develop many ways of looking at the same phenomenon.
And that can allow you to grow. So when people want to say, oh, it's just thermodynamics, I don't think they're thinking about it deeply enough. But if they're saying it's just classical curvature and that gravity is really classical, they're not thinking about it enough. So to me, that is not the mystery. And the structure is not the mystery.
The mystery is perhaps, and I'll get right back to it, is how things emerged and what did they emerge from? I think, you know, I can play around with ideas of what was there that caused emergence. My view is that apart from entropy and phase, which is also called quantum mechanics, it turns out, the log of
Schrodinger's psi wave function is i times complex action of which the real part is the usual action and the imaginary part is one half of the entropy. That's the universal relationship and at its heart
is the quantum phenomenon and quantum mechanics is the language of the universe and what it's doing it's saying that I do not I there are forces that are there in Schrodinger's equation for example that try and take the ensemble of possible realizations and make sure that they're spread apart see now I'm getting into where I
obviously some uncertainty, but that is where we are headed in my view. I mean, I am headed there. And what I am seeing is that everybody's headed there. That is to say, the concept of information and the laws of information, which is quantum information, all quantum, is the underlying architecture of everything. And so when you say is gravity,
quantum mechanics writ large yes it is but that's because it splits into entropy and action and the way entropy and action work is that it's a product of charge times response to charge so that this is kind of the universal story so then getting back to your questions I haven't forgotten it which is something about spin spins really interesting here and we could riff on that for a while
But the basic point is that the metric picture is a picture of effectively, even though it's done as metric squared, distance squared, at some level, it is an expression of either action squared or entropy squared. And so, okay, that's interesting.
But it's like, what am I going to say? There is something called the density matrix in quantum mechanics, which encodes all of the information. And it basically is telling you about how a system changes from one form to another. And what we do is we split it up into a product and we call that product the wave function.
So the density is a quadratic combination of wave functions. And what's interesting about that is that it's a complex product. So there are two elements. One is action, which is phase. And then there is the overall density aspect, which is entropy. Entropy is count.
and phase is coherence among counts. So I've taken you to where I am actually spending much of my thinking and how am I doing it? I'm doing it by concrete problems with many of my colleagues around here. So the theory of inflation is a fantastic playground for all of these ideas because
I want to use something which can actually have observable consequences in order to improve my comprehension of how the universe actually works. So that's what the quest is.
spin metrics. Well the first point is that usually we deal with four dimensions, time, three space. Then within string theory there was an argument for it being, depending upon how you did it, ten dimensions or eleven dimensions. To me every degree of freedom is a dimension which means that it's x, y, z, t
Zed by the way. And then all the fields. And the fields are dimensions. Why not? And so
then the issue is is a particle a particle itself a field or is it always a collection and that's an interesting issue. So in my view dimensions are relatively easy to create and destroy and it is not something that people should be overly intimidated by but of course historically we had this path
which meant that people's minds were kind of frozen in because it takes time for people to adapt and now I'd say that partly because string theory didn't break make the breakthroughs that people had thought because it's complicated I mean it may still be underlying but as a result of that all these bright minds have been pushing at
All these other questions in physics and it seems to me we're on the cusp of a real breakthrough in what unifies the whole thing together.
is essentially information theory. I mean, and I'm not the only one saying this. It's just that I came to it from a very different route. It's basically been where I've been going all along, but now I see he's doing, he's doing it, she's doing it, she's doing it. That is what is kind of dominating the minds. And then what it blends with is the Google lights in this world because they see the world as information and that's human information.
and human information and physics information, just like with Shannon information along channels and thermodynamic information. It's the same thing. So if we are talking about a theory of everything, a grand unified theory, then it must fundamentally engage in
Not just the existence of humans that happened on this little planet and, you know, chemical operations of unbelievable complexity all came together to produce this tremendous force of life which just is, doesn't seem to be, well, humans look like they can repress it, but is irrepressible. Life
everywhere, right? It's amazing how if something goes wrong, Mother Nature comes up with something else, something else, something else. That all has to be fully integrated. And the problem is that it seems so impossible because everything is so complex that how can you make a brand new fight theory? Well, you do it by saying there's principles
You wanted it to be framed in terms of laws. Law are unclear. I mean, that's the way people used to think about it, right? There's law. There has been, from above, a law has been dictated. But laws are created. Just like things evolve, a law can evolve. A law is an expression of a collective.
Act of Collective
And so this is one of the interesting things that I'm into now. We call these things effective potentials that define how flows, trajectories, realities change. And usually what you do in physics is you say, let there be this effective potential and then let's look at the consequences. But the view I have is that, yeah, but it feed feeds back.
and the law or the effect of potential changes. And so there is a feedback. Then the question is, how does it all fit together in some TOE? But the most important thing, maybe it's because I'm in my dotage, is that, I mean, this has always been the goal. I think it's everybody's goal. You want to have a grand unified theory that includes all of human phenomenology.
And not just from the point of view of us as kind of mechanical beings, but us as generators of ideas. And does this include consciousness? Yeah, yeah. Well, consciousness writ large, that is to say,
You know, Plato, Cave, little ideas become capital ideas, capital I. And he would have said it's the capital ideas which are the real truth and the little ideas are just the shadows that are playing out. I'm not
going to go that far, but the profundity of their thinking was enormous in my view. Everybody else would say the same thing, but it isn't translated into this world as much as it should be. That ideas are the things that have been the great creation. I mean, Mother Nature obviously created them in some sense, but we have something that happened on this planet.
which is the creation of these mega ideas, which required many things. We had to learn writing. We had to learn to speak to each other. We had to, that is all physics. So when you ask what is universe, the universe is you and you and you, and that is the subject. That's a subject of physics, theoretical physics. It's why I got so impassioned by it from the beginning.
because I think I had a glimpse of that's what it should be and could become whether or not I'll get there I don't know or whether you know I'll go laboring off on this except that it is an attempt within you know one being to have a mini grand unification I think that's what everybody is trying to do they're trying to unify their being under maybe not just one capital idea although religion is one capital idea
Does spirituality play into your life? I believe in everything and nothing. That is my mantra. And that is actually a fundamental statement of the universe. In condensed matter physics, what is fundamental are things called particles and holes. You know, in going back to matter and antimatter, which you wanted to raise earlier of why baryons and not antibaryons.
The holes are the positrons and the particles are the electrons. But it could have been that the positrons are the particles and the holes are the electrons. That is to say, it's totally reciprocal. It's just that something built the symmetry, relatively small force, but something created symmetry. It may sound like I'm escaping,
what you wanted to get at, which is everything I do is, I don't know, would you use the word spiritual? It is just trying to understand the raison d'etre, why, you know, age of reason, raison d'etre, what are we here for, what am I here for, what is happening, and
This is unfortunately the situation I'm at right now. The way I see it, it's not unlike ancient Hindu, I guess, that most of the universe writ large may be this kind of fluctuating component in which nothing special is arising and then every now and again
there is the development of coherence and coherence can breed instability and that's what happened in the alter the universe and a way to say that is that there was a bubble of Hubble parameter that was coherent so instead of it being all sorts of fluctuations like this it developed kind of something where this was connected to this connected to this and then that
coherence becomes unstable to further development. And so the universe that we can see is that sort of entity in which there's this huge degree of coherence. But if I were, well, I'm not going to bet on this, but I would say that the most natural situation is not to have that
It is
There's spirituality, there's more of philosophical spirituality, mathematical physics view of, but trying to integrate all of human phenomenology in the same basic umbrella. Then there was another question, I can't remember what that was.
Ah, well, you know, one of the amazing things is the sheer number of planets that are being observed now. I mean, there was a time when we only had the nine and we had the eight, if you know what I mean with Pluto. But we have this huge panoply. It is
ubiquitous that there are planets. And at least with the Earth as an example, which is clearly, in my view, special, not just because we're here, but because of this incredible balance of how water came out and is in all of its forms and it's got, you know, the courage is just right, you know, I mean, it's amazing.
But there are so many planets, conditions not unlike that may have happened, and life will choose further paths in order to organize its chemistry. And the organization of chemistry is just so amazing. It's one of the things that intimidates me about trying to do a TOE or granification. It is, you know, how this unbelievable complexity
emerged from simplicity, and it's playing out. It played out in the early universe with the development of nucleons, then nuclei, then atoms, and then the atoms cohere, but we needed to make complex atoms in the furnace of stars in order to create planets which could then create life. I mean, it's amazing that all of this stuff
was worked out. And I guess that means that Mother Nature is, you know, working out our equations as we're going, I don't know. And so that's why I don't really have that view. I often use the terminology Mother Nature just to give it not because I'm anthropomorphizing, it's just because
Things happen that I'm not in control of, and Mother Nature is in control of them and has defined all of us, and it's amazing how she has. Anyway, I would like to find a TOE, so this is getting back to the original thing, but the TOE must have
What's important to consider for the future? I think that what is probably unstoppable
is the transcendence of human beings as biological entities. We can see it. We have these devices, but this is now as if it's part of my brain.
The amount of exterior information in this is outrageous and is full connection and it's connecting us. Fortunately, I don't tweet, but it connects everybody and everybody's buzzing and it's making well, you know, the word is the high mentality and all of that.
and it's got pluses and it's got minuses. Obviously their minuses are completely evident in this day and age, but the pluses are there as well. The amount of information that I can get just from this thing right here and now is just outrageous. So then that's the integration of the machine into the being of the human being.
And that's unstoppable, no matter what people say, no matter, you know, Elon Musk and others are saying, Oh, we have to worry about the development of the machine life. I don't think that we can stop that. That's the natural flow of information. And then, you know,
If that's true, how did that manifest itself with civilizations that are more advanced than us? They will have integrated with machines. I mean, what's the difference between a biological machine and a mechanical machine? And why wouldn't they be intimately related? Because, you know, you can make complex chemical things in a machine. So what is our future?
That's just impossible. We can't even say it here and now in 2023, by the way, of what things will look like in 2050. I mean, you can't because it's moving so fast. Things are integrating so fast. Our problem is instability. Now, I've extolled the virtues of instability in creating universes.
But instability can also create disasters, and we are moving towards a disaster, which is that this precious planet, I'm just saying what everybody knows, this precious planet is being transformed by human interactions because we are this collective hive that's able to make these transformations, and we've got such a large number of people
that it requires an incredible amount of us being self-controlled and able to manage as a coherent entity, humanity. So it is, you know, futurologist, what's a futurologist?
They don't know. Nobody knows because it's all changing so rapidly. I mean, the changes in my life have been amazing. The change that you're seeing is amazing. And then what's coming is either even more amazing or even more disastrous. It's just a question of whether that we can, you know, gain control over the forces that are going to try and split us all apart.
So if we then want to say what about the theory of everything within this context, one way or another, that's what we're going to be moving towards. And I think it'll be based upon information theory, quantum information, because that's the law of the land.
And, you know, is it going to be from how the computer or is it going to be from, you know, one or two people with their blackboards? And the answer is probably how. But this is, in my view, much more creative and fun. And then the other thing that I will fold into that is that
You know, we've all been zooming our life away in the last few years, and that's not a bad way of communicating, but there's something intangible about humans in the same room in relatively small groups interacting together, basically getting intellectually high together with ideas, ideas again, and that
is precious. And I guess machines can get there. Why wouldn't they? They can enhance it. But it's something which is not reproducible over Zoom. So that gives hope for the biological machine that there is a phenomenology which is occurring, which we do not understand really. Although, of course, many people with religion think they understand it. But that's anyway, so future is murky.
The podcast is now concluded. Thank you for watching. If you haven't subscribed or clicked on that like button, now would be a great time to do so as each subscribe and like helps YouTube push this content to more people. Also, I recently found out that external links count plenty toward the algorithm, which means that when you share on Twitter, on Facebook, on Reddit, etc.
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"text": " My name is Dick Bond. I'm at the Canadian Institute for Theoretical Astrophysics, which is based at the University of Toronto, but it is flung across all of Canada under the guise of CETA, Canadian Institute for Theoretical Astrophysics. I'm a theoretical astrophysicist, a cosmologist, first and foremost a theoretical physicist. I've been thinking about these universal matters."
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"start_time": 141.288,
"text": " And what was so compelling about it is that he was trying to take the information they had then on the universe and on formation of Earth geology and all that and life for that matter. And he tried to make a synthesis of going from basically the beginning through to the evolution of life on Earth. This is one book."
},
{
"end_time": 175.811,
"index": 7,
"start_time": 171.527,
"text": " And it was amazing, amazing that human thought could try and"
},
{
"end_time": 205.896,
"index": 8,
"start_time": 176.886,
"text": " capture this. Of course we have gone a large distance from the information he had back then, but on the other hand he was a very smart guy and this was pretty compelling and I'm not the only one. I was talking to somebody at NYU, a great professor there, and it seems that she of the same era as me had the same"
},
{
"end_time": 235.401,
"index": 9,
"start_time": 205.896,
"text": " At one point I wanted to be a writer, and then I said,"
},
{
"end_time": 248.131,
"index": 10,
"start_time": 236.681,
"text": " You can't write without knowing what the leading edge of human thought is on reality if you like."
},
{
"end_time": 269.036,
"index": 11,
"start_time": 248.439,
"text": " anybody who's writing without being there is writing something which will maybe will have things like emotional truth and other such things but it cannot be a correct statement not that what the students are reading now are correct anyway so what i did is i sort of shot my bow from that period"
},
{
"end_time": 285.503,
"index": 12,
"start_time": 269.036,
"text": " And the arc of my career has been exactly the attempt to do this kind of full integration of thinking and trying to take science, which means knowledge, and apply it to"
},
{
"end_time": 315.418,
"index": 13,
"start_time": 285.503,
"text": " The thing that really matters to me, which is the eye, that is to say the science is the way to try and comprehend one's self and the place in the universe, which is not an easy thing to do and most people have minds that are split into a lot of channels and many of the channels don't talk to each other, but a goal ultimately is to integrate and now that I'm of an age,"
},
{
"end_time": 344.667,
"index": 14,
"start_time": 316.442,
"text": " Do you believe that science is the cutting edge?"
},
{
"end_time": 350.196,
"index": 15,
"start_time": 345.486,
"text": " The modus operandi for humans to"
},
{
"end_time": 382.125,
"index": 16,
"start_time": 352.312,
"text": " Understand and see the universe and that it was the great development. I mean I can go back to Definitely the Greeks the pre Greeks through the whole Period of the Renaissance and in particular there is that period that is called the age of reason We have now entered into the age of unreason in the world around us although everything is trying to"
},
{
"end_time": 398.012,
"index": 17,
"start_time": 383.404,
"text": " Unify with everybody communicating with information and the information flood is kind of overwhelming and it does split into streams and we see this manifested all around us."
},
{
"end_time": 426.305,
"index": 18,
"start_time": 398.251,
"text": " But what should be at the core is the basic quest for knowledge, which is the quest for science. So science is then transcending just physics or chemistry or biology. It is at the heart of humanity and how people should be operating. That is to say you want knowledge and you want to apply knowledge to the world around us. What's meant by the term universe?"
},
{
"end_time": 456.067,
"index": 19,
"start_time": 426.92,
"text": " Well, that's an interesting question because what is often put out there is the word which I am not that fond of, although many of my friends like to use it, the multiverse. There is only universe. That's what the uni is in front. It's the one. And then the question is, how complex is it? But it is all that there is basically by definition. The thing that is very humbling, if you like,"
},
{
"end_time": 478.439,
"index": 20,
"start_time": 456.715,
"text": " The universe seems vast, the part that we can see, but the way we think of it now is that what we see is only a tiny part of a much, much greater whole. Then the question is, is it all connected or are there disconnected elements? Well, if it is a completely disconnected element, we could never know about it because there's no communication."
},
{
"end_time": 498.814,
"index": 21,
"start_time": 478.439,
"text": " The things that are beyond the speed of light reach, we don't get information on. The only way we can get that information is by looking around us in the universe, try to understand how the patterns have developed and then say,"
},
{
"end_time": 511.101,
"index": 22,
"start_time": 499.224,
"text": " I'll go back to 123 infinity. You then say that this applies to the regions that you cannot see. That, of course, is impossible to get right, really."
},
{
"end_time": 539.667,
"index": 23,
"start_time": 511.647,
"text": " But on the other hand, it is clear that the themes that we see around us and out to the observable edge of the universe, there is a commonality. I mean, that is an amazing thing, right? That, you know, you don't go into some area of the universe, which is drastically different. I mean, in time, it's different because it evolves, but"
},
{
"end_time": 555.367,
"index": 24,
"start_time": 539.667,
"text": " It isn't like, at least in the patch that we can see, that there is a coherence. The coherence is essential basically, but for me, I don't really see why there should be coherence."
},
{
"end_time": 579.497,
"index": 25,
"start_time": 557.142,
"text": " I mean, coherence writ really large, that is to say everything connected. In fact, one of the things that I'm known for is of label the cosmic web, which of course web means something to everybody because of the internet web. But what"
},
{
"end_time": 592.466,
"index": 26,
"start_time": 579.787,
"text": " That word or those words cosmic web indicate is the interconnectivity of everything and that every aspect of the universe is connected with every other that sort of"
},
{
"end_time": 615.23,
"index": 27,
"start_time": 592.927,
"text": " cliche and obvious, but it's also incredibly profound. It means that everything is dressed in the interactions with everything else. And in particular, it's writ large in the universe that we can see. But for me, the universe is beyond that."
},
{
"end_time": 637.978,
"index": 28,
"start_time": 615.23,
"text": " And one way you can think about this is I don't want to get into the concept of the universe of simulation, although that's an interesting point. But in a sense, we think of the universe as a realization of reality. And then"
},
{
"end_time": 645.623,
"index": 29,
"start_time": 639.104,
"text": " We think there can be a lot of realities and at some level quantum mechanics"
},
{
"end_time": 672.125,
"index": 30,
"start_time": 646.561,
"text": " has those realities interacting with each other because the quantum theory is one of its basic elements is that information diffuses which means that you don't you cannot over concentrate information so it flows out I mean that's a manifestation of that as things like the hydrogen atom etc where"
},
{
"end_time": 692.398,
"index": 31,
"start_time": 672.125,
"text": " You don't have the electric charge rate at the center on top of the proton. The uncertainty aspects of the universe enforce through this kind of interaction that it's got a ground state. I may be going too far here, but it's got a ground state structure."
},
{
"end_time": 719.07,
"index": 32,
"start_time": 692.398,
"text": " and you know that's manifested everywhere that there are these structures that occur and one aspect of the structure is information trying to propagate from whatever the origin is to throughout the universe. I mean that's sort of one of the main themes that I work on in what I do research on. That was a long way from what is universe"
},
{
"end_time": 738.046,
"index": 33,
"start_time": 719.36,
"text": " But in fact it isn't, because it's in my view at the heart of the universe. Regarding complex structure, how does it arise? You know, we have a mantra, and the mantra has been in place from, well actually you could really trace it to around 1980 or so, but maybe even a bit before."
},
{
"end_time": 762.79,
"index": 34,
"start_time": 738.046,
"text": " but not well formed then, which is that there is something fundamental which we believe is happening all around us. Something that we work with all of the time. Everything is built upon it. We call it the vacuum, which sounds like it's nothing, but in fact the vacuum is like everything."
},
{
"end_time": 782.875,
"index": 35,
"start_time": 763.251,
"text": " And that'll probably become clear as I say more. But within the vacuum, there are these fluctuations are often called virtual fluctuations. What does it mean to be virtual? It means that humans aren't seeing it. But if you take the vacuum,"
},
{
"end_time": 809.292,
"index": 36,
"start_time": 783.677,
"text": " and fend it then you get observable consequences and one of the observable consequences is all of the structure in the universe or at least that's the current picture and so uh and it's a picture which is so compelling it's one of the reasons i put so much energy into trying understand the concept of deformed vacua which is so anyway the basic picture and"
},
{
"end_time": 836.937,
"index": 37,
"start_time": 809.633,
"text": " These fluctuations are happening all around us and you know at some level all of your structures Yourself is built upon that underlying structure of this what you might call vast sea of fluctuations that exists and that all of Phenomenal reality is played on top of that Hugh it's like a huge sea and here we're sort of you know, I"
},
{
"end_time": 861.852,
"index": 38,
"start_time": 838.797,
"text": " Sailing along the surface of that sea and we don't know how deep the sea is. We don't know how far the vacuum goes It may go I doubt anything goes to infinity but it could and so the"
},
{
"end_time": 892.892,
"index": 39,
"start_time": 864.275,
"text": " Anyway, so the vacuum is fundamental fluctuations that are like virtual, I mean people think of it as virtual particles. So you think of charges like plus and minus, plus and minus always appearing, but that they don't actually break apart from each other so that you actually can observe in your detector a plus or a minus. They're kind of always oscillating and blending, but the same"
},
{
"end_time": 900.589,
"index": 40,
"start_time": 893.234,
"text": " aspect is that that's kind of a so-called fermion picture where there's uh well i i actually don't"
},
{
"end_time": 923.353,
"index": 41,
"start_time": 901.118,
"text": " Want to get heavily, unless we go there eventually, into fermions and bosons? We probably will, but maybe not at this point in the conversation. Anyway, the basic mantra is quantum fluctuations, but that isn't the important issue. That they exist is fundamental. That they condense and freeze out"
},
{
"end_time": 944.019,
"index": 42,
"start_time": 923.968,
"text": " and freeze in patterns of density, fluctuations, gravitational potential fluctuations. Those things are what ultimately grows to make all of the complex structure of the universe. So we have what is in effect a relatively"
},
{
"end_time": 956.647,
"index": 43,
"start_time": 944.599,
"text": " Simple theory. I mean, it's ridiculous that we think we can think about it, which is, you know, the first 10 to the minus 33 seconds of the universe and all of that, but we do"
},
{
"end_time": 985.384,
"index": 44,
"start_time": 957.022,
"text": " and it just seems like home those thoughts right and that consequences are everything and we actually think we can observe them through the impact on things like the cosmic microwave background the photon afterglow the big bang and and many other things so we have a a theory where we can make observations here and now on earth in the large scale structure of the universe"
},
{
"end_time": 1003.422,
"index": 45,
"start_time": 985.384,
"text": " and interpret what we think is going on at these unimaginably early times and part of that is because what was happening at those unimaginably early times at least in the region that we can see seems to have been relatively simple. We're looking for"
},
{
"end_time": 1030.384,
"index": 46,
"start_time": 1004.343,
"text": " more complexity in what emerged from the Ultra-Early Universe because that would give us more information. But right at the moment, the amount of information we're getting is we're essentially compressing all of the information in the Ultra-Early Universe into what is in effect two numbers. It's hard to believe, but that's the story. I mean, that is the general point about structure formation. Then"
},
{
"end_time": 1060.64,
"index": 47,
"start_time": 1030.896,
"text": " As the universe evolves, species emerge. I'm not unlike in evolution, biological evolution, so there may be some kind of grand unification soup, which I think is probably correct, inflationary energy, and I know you want to get to this eventually, that is to say what is called dark energy, that that's like this kind of universal coherent"
},
{
"end_time": 1090.128,
"index": 48,
"start_time": 1061.237,
"text": " energy that splits up into what is ultimately all of the species of the universe and then it and then the universe passes through various epochs where certain of those species are more important than in other times. Species come and species go and we're dealing with some kind of fossil relic which is a non-trivial one because it's what makes us up."
},
{
"end_time": 1110.981,
"index": 49,
"start_time": 1091.118,
"text": " Can you explain how the universe expands and what's meant by it? Contrary to popular view, it's true that on large scales the universe around us is expanding, but it is not expanding here in this room. It's in effectively a state of equilibrium."
},
{
"end_time": 1125.23,
"index": 50,
"start_time": 1111.476,
"text": " And so when galaxies and other such things form, there is no expansion associated with that. This is a good thing, otherwise we would all be getting fatter because of the universal expansion."
},
{
"end_time": 1153.916,
"index": 51,
"start_time": 1126.715,
"text": " On the large scales, very large scales, there's an expansion. The expansion is characterized by a rate of expansion. It's called the Hubble parameter. I'm sure you've heard of it, which is basically just the expansion rate of the universe. But you can also think of it as spatially dependent. And so in our region of the universe, our galaxy here, there is effectively"
},
{
"end_time": 1174.957,
"index": 52,
"start_time": 1155.282,
"text": " The Dynamical Universe"
},
{
"end_time": 1193.336,
"index": 53,
"start_time": 1175.623,
"text": " And now I'm losing the thread of where we were trying to go basically because I was going someplace. I was trying to give you a way of looking at the universe that is actually not standard. But if I'm to look around me, which if I can, I will. This is a, uh,"
},
{
"end_time": 1211.442,
"index": 54,
"start_time": 1193.933,
"text": " Undergraduate student is working with me. This is density against time showing the thermal history of the universe as it starts at the beginning and goes through various phases. I know you're going to ask this question later, but I thought, thanks for arranging my prop."
},
{
"end_time": 1242.005,
"index": 55,
"start_time": 1212.824,
"text": " And here were four points about what we were going to do. She's still engaged with this with me. And one of them is the H naught tension, which has gotten a lot of press recently because from the cosmic microwave background, which is this really high precision thing that I've been very much engaged with throughout my entire career, uh, we get a certain value of how rapidly on large scales the universe is expanding on average."
},
{
"end_time": 1271.237,
"index": 56,
"start_time": 1242.722,
"text": " And then there are other claims using things like supernova and stars of a specific form that the value is different in the quite general cosmic neighborhood around us. This is called the H naught tension, the expansion rate tension. And it's the number of meetings about this is enormous around the world."
},
{
"end_time": 1296.817,
"index": 57,
"start_time": 1271.698,
"text": " And the issue is whether it's a systematic effect of not understanding the data well enough or whether there is some new profound thing associated with something that happened relatively late that caused this expansion to change. We already know that the expansion is changing. In fact, that was part of the great discovery of what's called the dark energy."
},
{
"end_time": 1323.404,
"index": 58,
"start_time": 1297.329,
"text": " But it may be that there is a different expansion in the area around us. Razor blades are like diving boards. The longer the board, the more the wobble, the more the wobble, the more nicks, cuts, scrapes. A bad shave isn't a blade problem. It's an extension problem. Henson is a family owned aerospace parts manufacturer that's made parts for the International Space Station and the Mars Rover."
},
{
"end_time": 1351.869,
"index": 59,
"start_time": 1323.404,
"text": " Now they're bringing that precision engineering to your shaving experience. By using aerospace-grade CNC machines, Henson makes razors that extend less than the thickness of a human hair. The razor also has built-in channels that evacuates hair and cream, which make clogging virtually impossible. Henson Shaving wants to produce the best razors, not the best razor business, so that means no plastics, no subscriptions, no proprietary blades, and no planned obsolescence."
},
{
"end_time": 1368.234,
"index": 60,
"start_time": 1351.869,
"text": " It's also extremely affordable. The Henson razor works with the standard dual edge blades that give you that old school shave with the benefits of this new school tech. It's time to say no to subscriptions and yes to a razor that'll last you a lifetime. Visit hensonshaving.com slash everything."
},
{
"end_time": 1398.114,
"index": 61,
"start_time": 1368.234,
"text": " If you use that code, you'll get two years worth of blades for free. Just make sure to add them to the cart. Plus 100 free blades when you head to H E N S O N S H A V I N G dot com slash everything and use the code everything. Out to a fairly large distance and then on even larger distances. So this is a puzzle. And why did I do this? I was just trying to say that"
},
{
"end_time": 1426.067,
"index": 62,
"start_time": 1398.439,
"text": " there is a simple way of thinking about the evolution of the universe as long as you add position as well as time into how you think about it and that it's inhomogeneous and that it's the same basic language but it is rarely used that way in the subject which one of my missions even with undergraduates is to teach that way of looking at things"
},
{
"end_time": 1446.374,
"index": 63,
"start_time": 1426.749,
"text": " What is dark energy? Dark energy, well it emerged as so-called Einstein's cosmological constant and back in 1917 or so,"
},
{
"end_time": 1475.811,
"index": 64,
"start_time": 1447.108,
"text": " The observations were such that there was no indication, A, that there was clearly external galaxies. And so it seemed like the stars and structure, they were just buzzing around us. So that on average, it was an equilibrium situation. And so yet when you take the laws of gravity, Einstein's theory, curiously enough, it would either contract or expand."
},
{
"end_time": 1496.067,
"index": 65,
"start_time": 1476.271,
"text": " Automatically the contraction is called gravitational instability and it's the way we understand how structure formed in the universe. It's the gravitational instability theory of the formation of structure. And so he said, well, you know, maybe the data is going to enforce me. So I'm going to put in a term."
},
{
"end_time": 1525.367,
"index": 66,
"start_time": 1496.834,
"text": " which the theory allowed and it's called the cosmological constant and then about a decade later or so somebody proved that that theory is unstable as well and Hubble discovered the expansion of the universe by looking at galaxies nearby and how they were moving away and you know this famous statement"
},
{
"end_time": 1547.807,
"index": 67,
"start_time": 1525.794,
"text": " Einstein's that it was the biggest blunder. He never apparently actually said that and it wasn't a blunder. It's at sort of the heart of much of our thinking because one way of thinking about it is that it's the energy density of the vacuum and I'm going back to the word vacuum. So when I write it,"
},
{
"end_time": 1571.459,
"index": 68,
"start_time": 1548.848,
"text": " I often use rho as density, many people use rho for density, sub-vac, as if that's an obvious thing, vacuum energy, except that, as I said earlier in this, in this brief thought flow, is that"
},
{
"end_time": 1601.22,
"index": 69,
"start_time": 1573.37,
"text": " The vacuum is fundamentally deformed. It's deformed by the expansion of the universe. It's deformed by structures in the universe. So vacuum is not actually this pristine thing that people think about anyway. The bottom line is that that was the original lambda and it was embraced by, well I won't go into the full history of this, but it"
},
{
"end_time": 1627.858,
"index": 70,
"start_time": 1601.561,
"text": " would rise up and go down and rise up and go down in terms of its stock, if you like, about whether people were interested in it. It kind of got resurrected for a few reasons around the mid 80s. And that's when I was, I thought it was a, you know, a great idea. Why? Because, uh,"
},
{
"end_time": 1657.637,
"index": 71,
"start_time": 1629.189,
"text": " As well as matter and radiation, the universe can have curvature. I mean, in fact, it's always got curvature on small scales. That's what causes the matter to concentrate. Anyway, the basic point is that there was this first indication for me that you needed something akin to a lambda. The reason of going back to the thread of thought there,"
},
{
"end_time": 1682.824,
"index": 72,
"start_time": 1657.995,
"text": " Curving the universe on average on large scales and yet having small fluctuations on smaller scales and we had evidence for that Anyway, the basic point is you have to have this large-scale curvature if you're going to have what is called an open or closed universe whether it's curved up like a sphere or curved down like a saddle and"
},
{
"end_time": 1711.459,
"index": 73,
"start_time": 1683.234,
"text": " That was, you know, what people mostly thought about. Whereas the vacuum energy density is something that's constant and scale independent, or at least that's the view. So then the other dilemma occurred. Well, how can it be as small as it would need to be to make a universe like ours? And that continues to be a huge mystery. Because if you count"
},
{
"end_time": 1742.193,
"index": 74,
"start_time": 1712.346,
"text": " The amount of energy density that you think is in the vacuum, it would depend upon the Planck energy scale. In fact, it would go like the fourth power, which is a huge, huge number, like nothing that we have ever seen, except the key element here is that you don't apparently get to observe that. You only get to observe differences or changes. And so maybe it can all be well understood that way."
},
{
"end_time": 1768.729,
"index": 75,
"start_time": 1742.978,
"text": " But anyway, so I liked Lambda. I liked it as a extension beyond just dark matter and burials, which are the stuff that we're made of. And so it became part of my kind of standard thing."
},
{
"end_time": 1798.643,
"index": 76,
"start_time": 1769.309,
"text": " And then we were dealing with two kinds of data. Cosmic microwave background as it was emerging, fluctuations that emerged from the universe around 380,000 years after the so-called Big Bang. And that's like 13.8 million years ago. So that was giving us valuable information. It's since filled in"
},
{
"end_time": 1821.203,
"index": 77,
"start_time": 1798.848,
"text": " brilliantly, but, you know, as it emerged, it was giving us an indication, but you had to, we had to add large scale structure to that, the spatial inhomogeneity on large scales of the universe, in order to say, it looks like lambda is pretty good. And we did."
},
{
"end_time": 1848.541,
"index": 78,
"start_time": 1822.142,
"text": " And then, so that was microwave background and large-scale structure observations. Then another set of groups, they were looking at supernova and they were developing something, curiously enough, it's called the Hubble diagram, where it's Hubble parameter as a function of time and"
},
{
"end_time": 1872.329,
"index": 79,
"start_time": 1849.104,
"text": " If you have an ordinary universe without any lambda it would have a certain shape and with lambda it has a different shape. And so after some stops and starts it emerged that that looked like it was also indicating accelerated expansion and that's the one that sort of"
},
{
"end_time": 1889.104,
"index": 80,
"start_time": 1873.78,
"text": " became the popular way of understanding about this emerged. But the microwave background and large-scale structure were right there as the underpinning of this whole story. And then there was another experiment that I was involved in that was called Boomerang."
},
{
"end_time": 1919.189,
"index": 81,
"start_time": 1889.821,
"text": " It was a microwave background experiment called Boomerang because you launch from the Antarctica and the prevailing winds at the top of the atmosphere caused the balloon to go around and around and around and so you get lots of data. And it was really the thing that sold the vast community, in particular the particle theorists, on that you have to take this extremely seriously. It's like"
},
{
"end_time": 1945.145,
"index": 82,
"start_time": 1919.531,
"text": " that that's clearly the answer. Then the issue is, what is the nature of this so-called dark energy? I mean, what does it mean to say an energy is dark? For that matter, this is a bit of a joke. For that matter, why do we call it dark matter? And why, since matter and energy are intimately related,"
},
{
"end_time": 1957.483,
"index": 83,
"start_time": 1945.913,
"text": " Why do we have this stupid label? But we do that in this subject. There are stupid labels all over the place. Some actually quite clever, but you know, up down strange charm is"
},
{
"end_time": 1980.794,
"index": 84,
"start_time": 1957.961,
"text": " is particle theory right so you know there's a little windsy that does occur but dark energy really doesn't convey the information it's actually a potential energy density that at the moment we observe only through its impact on the expansion of the universe and not in any direct experimental way the whole"
},
{
"end_time": 2004.957,
"index": 85,
"start_time": 1980.794,
"text": " is that we will be able to. And so, you know, billions of dollars actually have been put into experiments that give huge amounts of astronomical information. But one of their primary raison d'etres was to learn more about the dark energy, which you cannot learn from observations on the Earth in the lab."
},
{
"end_time": 2024.514,
"index": 86,
"start_time": 2004.957,
"text": " it is really something writ large in the ultra-large-scale dynamics in the universe. Anyway, it emerged as being an ingredient, and as time went on, it got, the observational evidence got stronger and stronger and stronger that that was it."
},
{
"end_time": 2052.995,
"index": 87,
"start_time": 2024.94,
"text": " And so there were two aspects to this. One is, is it just a uniform potential energy density so that everywhere, including in this row, there would be this uniform energy density that's sitting there. You wouldn't really be feeling it, but if it could, it wouldn't try and expand you. It's just that the other forces are so strong that that doesn't happen."
},
{
"end_time": 2070.828,
"index": 88,
"start_time": 2053.387,
"text": " So there's this kind of uniform energy density that we think is all pervasive, but the evidence we have for it is on very large scales. So then the question is, does it change in time?"
},
{
"end_time": 2096.8,
"index": 89,
"start_time": 2071.203,
"text": " And why is that interesting? It's because it says it might not just be potential energy, it might also have a kinetic component. You know, there are two types when you learn physics in school, there is potential energy and kinetic energy. And so what is the kinetic energy amount of the dark associated with the dark energy? So this is a blazing question. And as I said,"
},
{
"end_time": 2122.517,
"index": 90,
"start_time": 2097.295,
"text": " We're trying very hard to determine whether or not that's needed. At the moment, it isn't. And yet, some people say you'll never find it because it's uniform. It's got to be uniform. And I don't ascribe to that. I think that it can change. The thing that to my mind is the most interesting is if the dark energy"
},
{
"end_time": 2152.295,
"index": 91,
"start_time": 2122.961,
"text": " actually interacts with ordinary matter and dark matter so that it can have a spatial dependence, not a sharp spatial dependence, but a spatial dependence that can allow us to determine more about it because otherwise all we get is a number. What's the balance between matter and dark matter? You know, the fact is we have dark matter here in our galaxy holding it together"
},
{
"end_time": 2172.841,
"index": 92,
"start_time": 2152.807,
"text": " but we don't think that we have a very high concentration we do would have a concentration but not a very high concentration of dark matter in this room with this relative to the rest of everything else everything has its structural aspect and it's all describable in detail by"
},
{
"end_time": 2191.459,
"index": 93,
"start_time": 2173.268,
"text": " the laws of transport in the universe, something that I am very keen about because it's an issue of how does energy go from one place to another. And evolution is all associated with transport. And so"
},
{
"end_time": 2210.811,
"index": 94,
"start_time": 2192.108,
"text": " The transport of very unsordinary matter is different than the transport of dark matter and the transport of dark energy seems to be particularly simple, but hopefully not so simple that we can't learn more about it than just a single number."
},
{
"end_time": 2233.609,
"index": 95,
"start_time": 2211.578,
"text": " And so all of this is in this mix or this soup of ingredients. And I think this is one of the points you want to get to later. So jump into it now and actually go back to my prop here, which is the history of the universe, the so-called thermal history of the universe, starting with"
},
{
"end_time": 2246.101,
"index": 96,
"start_time": 2235.316,
"text": " This very high density, which is the inflationary epoch, the idea is that it was fluctuation this year that ultimately led to structure."
},
{
"end_time": 2274.94,
"index": 97,
"start_time": 2246.869,
"text": " then there is a point at which that incredible coherence breaks up. A colleague who's actually just in the office next door and I, we coined the phrase a shock in time, so that you have this universal accelerated expansion, which is the dark energy of its time, alter the universe, but then it kind of shatter isn't the word, but it"
},
{
"end_time": 2299.394,
"index": 98,
"start_time": 2275.555,
"text": " shocks and becomes all of these kind of fluctuations like photons and electrons and positrons and all of the normal quarks and hadrons and other things that have to arise from our, you know, our observations show it, our existence shows it."
},
{
"end_time": 2324.07,
"index": 99,
"start_time": 2299.633,
"text": " And that is a period in which the density changes. That's a period in which radiation dominates. And there are a number of epochs that are associated with that. There is the so-called Hadronic era, which is the period where you haven't formed"
},
{
"end_time": 2347.824,
"index": 100,
"start_time": 2325.128,
"text": " that it's primarily a quark-gluon plasma, which means that the quarks haven't really, you know, completely gone into neutrons and protons, and then you have all of these, which later become mesons, all of these so-called gluons, which are the glue that holds them together, and the gluons and the quarks"
},
{
"end_time": 2370.06,
"index": 101,
"start_time": 2347.824,
"text": " They are all relativistic and have this large density. See, I'm speaking as if this is an absolutely obvious stated, you know, from above we had these tablets and that is not true. Everything that one thinks about the elderly universe, you know, there could be the rug pulled up from under us or maybe a different way of thinking about it, but"
},
{
"end_time": 2395.486,
"index": 102,
"start_time": 2370.06,
"text": " The evidence is amazing for the story of cosmic evolution. So we have gone through to the quark era, but then the quarks and gluons, but then they basically freeze out first into one that's dominated by mesons as well as neutrons and protons. But the neutrons and protons are sort of"
},
{
"end_time": 2417.892,
"index": 103,
"start_time": 2395.998,
"text": " small ingredients relative to the total. I know you want to get to this question as well. So we'll get there. Don't worry. It's nice that I have my prop though. And there is a period in which you transition from basically free quarks and gluons that are all in some what's called a plasma"
},
{
"end_time": 2442.739,
"index": 104,
"start_time": 2418.66,
"text": " not unlike the plasmas that we're used to with the electrons and ions, etc. And then it becomes hadronic, which means that because of the expansion of the universe, you've moved things far enough apart that forces caused"
},
{
"end_time": 2449.206,
"index": 105,
"start_time": 2442.739,
"text": " Basically a spectrum of mesons with different masses to form."
},
{
"end_time": 2478.831,
"index": 106,
"start_time": 2449.343,
"text": " Ultimately, as the universe continues to expand those annihilate, and at least behind the protons and the neutrons, there's still a huge amount and most of the energy is in electrons and protons and neutrinos and photons. And that is what is called the lepton era of the Big Bang, or at least used to be called that. I mean, to me, it's just a continuous situation. And that is the period that hear that sound,"
},
{
"end_time": 2505.947,
"index": 107,
"start_time": 2479.838,
"text": " That's the sweet sound of success with Shopify. Shopify is the all-encompassing commerce platform that's with you from the first flicker of an idea to the moment you realize you're running a global enterprise. Whether it's handcrafted jewelry or high-tech gadgets, Shopify supports you at every point of sale, both online and in person. They streamline the process with the Internet's best converting checkout, making it 36% more effective than other leading platforms."
},
{
"end_time": 2525.794,
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"start_time": 2505.947,
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},
{
"end_time": 2555.401,
"index": 109,
"start_time": 2525.794,
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},
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"text": " Think Verizon, the best 5G network is expensive? Think again. Bring in your AT&T or T-Mobile bill to a Verizon store today and we'll give you a better deal. Now what to do with your unwanted bills? Ever seen an origami version of the Miami Bull?"
},
{
"end_time": 2599.889,
"index": 111,
"start_time": 2578.2,
"text": " Jokes aside, Verizon has the most ways to save on phones and plans where you can get a single line with everything you need. So bring in your bill to your local Miami Verizon store today, and we'll give you a better deal. Rankings based on root metrics, root score, report data to 1-H-2025, your results may vary. Must provide a post-paid consumer mobile bill dated within the past 45 days. Bill must be in the same name as the person who made the deal. Additional terms apply. In around a minute,"
},
{
"end_time": 2620.589,
"index": 112,
"start_time": 2600.384,
"text": " in which hydrogen and helium nuclei get the patterns they do. So it's called Big Bang Nucleosynthesis, for nuclear, and the reactions that occur create"
},
{
"end_time": 2633.729,
"index": 113,
"start_time": 2621.015,
"text": " the light elements. Mostly helium and hydrogen remains and so most of the universe is hydrogen and helium. There's some deuterium and you don't get very much"
},
{
"end_time": 2660.862,
"index": 114,
"start_time": 2634.531,
"text": " almost none carbon and oxygen and iron or anything like that that is delayed until the formation of stars and you forge those in the nuclear furnaces of the stars and then you have to explode things and blow them out so we're passing through these epics this thermal history and so we've gone through this dominance of relativistic particles"
},
{
"end_time": 2677.312,
"index": 115,
"start_time": 2661.561,
"text": " So here it was dominated by what was you might call it ultra early dark energy. Then we have this period of dominance by radiation and then"
},
{
"end_time": 2703.439,
"index": 116,
"start_time": 2680.742,
"text": " There is an epic, maybe a hundred thousand years after the Big Bang, where you begin to transition to the dominance of matter, which is non-relativistic. That's when the protons and the neutrons in the dark matter basically take over the dominant things in the expansion. And that's also"
},
{
"end_time": 2733.285,
"index": 117,
"start_time": 2704.036,
"text": " When the photons decouple, the word decoupling is something I may use later. As the universe expands, various things at various times decouple. An extremely important one is when the cosmic microwave background, the photon after glow, the big bang, basically stops strongly interacting with the electrons. And so they"
},
{
"end_time": 2763.456,
"index": 118,
"start_time": 2733.507,
"text": " can split apart and we observe the residue of that in the cosmic background radiation. Thank you for this prop as well. This was from the so-called Wilkinson Microwave Anisotropy Probe, the beach ball. It shows the tiny fluctuations in the microwave background from which we learn so much. And this is basically trying to be a snapshot"
},
{
"end_time": 2784.121,
"index": 119,
"start_time": 2763.882,
"text": " of the universe."
},
{
"end_time": 2810.998,
"index": 120,
"start_time": 2784.309,
"text": " the Planck satellite. This was an early version of Planck as we were taking all of the stuff in front of it, and these are the fluctuations. Planck is still the best experiment and the best information, and I've been involved in that a long time, and it's the best indicator for lambda, the cosmological constant. Anyway, so that's this period."
},
{
"end_time": 2837.466,
"index": 121,
"start_time": 2811.817,
"text": " of dominance by non-relativistic matter and with the photons having propagated up, that was essential for the structure to start collapsing and forming and allowing the ability for galaxies and ultimately planets to form. You had to get it out of the A, dominance by dark energy and B,"
},
{
"end_time": 2860.589,
"index": 122,
"start_time": 2837.688,
"text": " out of the dominance of radiation in order for a structure to have formed. So that's an extended period. And then in a well, depends how you rate this, but not so long ago in cosmic history, we now see that it's this expansion"
},
{
"end_time": 2889.241,
"index": 123,
"start_time": 2861.34,
"text": " is trying to go towards this uniform energy density which is the new form of the dark energy so it's a interesting thing that we begin with what is in effect dark energy theory which is the emergence of the universe and then we end up with a dark energy which is the late time behavior so dark energy dark energy now what is really curious"
},
{
"end_time": 2919.462,
"index": 124,
"start_time": 2889.599,
"text": " is that there is no grand unified theory between this and this, which is just egregious. But there are many egregious things in this diagram which I have not gotten into, not egregious, hints that we haven't folded into the full unfolding of the cosmic evolution story. For example, the passage from when it was dominated by radiation to when it was dominated by matter"
},
{
"end_time": 2926.391,
"index": 125,
"start_time": 2919.872,
"text": " happens to be relatively close in time to when the"
},
{
"end_time": 2955.759,
"index": 126,
"start_time": 2927.722,
"text": " electrons started to coalesce onto the protons and make hydrogen atoms so the universe passed from fully ionized plasma into a largely neutral medium and that, that those numbers are close to each other is weird and there's no explanation for that. Similarly there's no explanation, although people have tried of course, for why the"
},
{
"end_time": 2976.783,
"index": 127,
"start_time": 2956.254,
"text": " That amount of baryons, ordinary matter, is so closely tied to the amount of dark matter. There's sort of a factor of six in between them, but six in cosmological terms isn't very much. And so a full theory should be able to tell us exactly why that's so, and it can emerge"
},
{
"end_time": 2995.998,
"index": 128,
"start_time": 2977.09,
"text": " It's just that there is no solidified understanding of why that should be true. I think you want to mention wimps in the future. There was something called the wimp miracle, which does tend to give"
},
{
"end_time": 3024.292,
"index": 129,
"start_time": 2997.125,
"text": " by chance relationship between the two. But, you know, just, well, anyway, I can go on and on. So maybe you might want to redirect me into something else. I have just given you the full thermal evolutionary history of the universe and then a question that naturally comes to mind. What happened? It's a good prop. It was well arranged."
},
{
"end_time": 3033.387,
"index": 130,
"start_time": 3024.974,
"text": " What happened before here? That's time zero. And what's going to happen out here, which is time infinity if there is such a thing?"
},
{
"end_time": 3063.78,
"index": 131,
"start_time": 3034.138,
"text": " And obviously, you know, we may have a lot of hubris, but not that much hubris. But the standard picture is that if it really is a potential energy dominated, then the expansion just continues exponentially. That doesn't mean that everything disappears. That's ordinary. It's just that everything is being"
},
{
"end_time": 3091.101,
"index": 132,
"start_time": 3064.189,
"text": " kind of not fully but somewhat torn apart by the dark energy which is trying to do an accelerated expansion so even things that are stable right now might not be stable I mean there are many reasons for the instability but then you know once upon a time fooled around with the theory in which this would go up like that"
},
{
"end_time": 3115.862,
"index": 133,
"start_time": 3091.613,
"text": " where the density goes up. And then it would go up to a point and start the whole cycle again, which is kind of a cyclical version of the universe, of which many people have played that game over time, and it's still popular in certain circles. But the main point is we don't know. It's really interesting physics if it's true."
},
{
"end_time": 3143.609,
"index": 134,
"start_time": 3116.271,
"text": " but we don't have an indication really about you know what the long-term behavior is here so we can't really predict our future and what is I have my own ideas not that different from some other people's ideas on how we go from before times zero through to there is no time zero is the basic"
},
{
"end_time": 3172.483,
"index": 135,
"start_time": 3143.763,
"text": " answer it is that the expansion of the universe which is necessary the coherent expansion universe which is necessary to make the universe as we see it around us it emerges it emerges from some maybe it's you could call it a quantum soup or something with again fluctuations all over the place"
},
{
"end_time": 3198.558,
"index": 136,
"start_time": 3172.841,
"text": " Anyway, all of that is, of course, I mean, you have to be very careful here. What do you know? What do you think you know? And what's heavy speculation? There's a lot of fun in heavy speculation. And, you know, you can do some theorizing. And what we prize most, I'm a theorist, what we prize most is a"
},
{
"end_time": 3222.125,
"index": 137,
"start_time": 3198.729,
"text": " The detailed mathematical understanding of the kind of phenomenon that one's trying to explore, explore mentally, exploring it observationally, really, not these utterly ethics. I mean, you would like to find some signature of what happened at time before the Big Bang or whatever, and people have proposed those things to"
},
{
"end_time": 3245.213,
"index": 138,
"start_time": 3222.125,
"text": " These are highly speculative, great fun. And then the question is, when you get"
},
{
"end_time": 3271.647,
"index": 139,
"start_time": 3246.015,
"text": " The avalanche of papers, which constantly appear on these subjects, how much attention do you want to give to each one? Because, you know, a lot of it's whistling in the wind as well. Playing in the sandbox is maybe another way to say it. What does the Hubble tension indicate about the future of the universe? This issue of the Hubble tension, if it's physics"
},
{
"end_time": 3299.548,
"index": 140,
"start_time": 3272.176,
"text": " then it's saying that something different than what we think is going on. And there is some kind of passage that has occurred and the time of that passage would be later than when the current dark energy overtook the non relativistic dominance of the universe. And so that's, you know, obviously exciting."
},
{
"end_time": 3323.729,
"index": 141,
"start_time": 3299.974,
"text": " if true, and the skepticism or worries that occur is that these observational campaigns are really difficult to get right. And one of the advantages paradoxically of the cosmic microwave background at 380,000 years is that it's relatively simple to understand"
},
{
"end_time": 3354.206,
"index": 142,
"start_time": 3324.275,
"text": " whereas once you're dealing with real astrophysics supernova and uh... sephi variable stars and things like this there are all sorts of effects that you may not be able to fully deal with theoretically and you just use as uh... well it looks like this is the trend so let's use that law and let's say that it's perfect everywhere uh... anyway so that's into the dark energy thing so it makes"
},
{
"end_time": 3374.77,
"index": 143,
"start_time": 3355.333,
"text": " I mean nominally the density on average is related to this Hubble parameter and so if the Hubble parameter is like 10% difference roughly speaking according to this Hubble tension"
},
{
"end_time": 3392.363,
"index": 144,
"start_time": 3374.77,
"text": " Then if you were really naive, you'd say, ah, something has happened to cause the H to go up. What is that? And so it would be a really profound implication for the universe at large if it turns out to be true. And we will get"
},
{
"end_time": 3422.671,
"index": 145,
"start_time": 3393.046,
"text": " the better and better experimental information on this. I mean, there's no question we have these change campaigns that are going on. Uh, the, uh, James Webb telescope, of course, is the thing that is most, uh, in the public mind, but the number of, uh, of experiments, the observations observatories in all wave meds that are covering"
},
{
"end_time": 3450.469,
"index": 146,
"start_time": 3422.892,
"text": " The sky is just enormous and it's a tribute to humans that they've decided that this is one of the places where our resources should be put into. And, you know, I believe in this strongly. I should because I'm an astronomer, but I believe in this strongly because it's going back to treating the universe in terms of the ideas of the age of reason, which is where we were at at the beginning, which is reasoned."
},
{
"end_time": 3478.558,
"index": 147,
"start_time": 3451.22,
"text": " How can we reconcile the variance of dark matter? Anyway, but then you were asking about the issues of dark matter and what is it, and we know of it at the moment only through its effect on gravity. That doesn't mean that it's not dark matter or that other alternatives are reasonable."
},
{
"end_time": 3504.002,
"index": 148,
"start_time": 3478.933,
"text": " I mean, we have a lot of really interesting evidence for it that has actually been around since the 1930s. It sort of picked up steam around the early 70s. And I'll just explain that for a second. So in the 30s, a very smart guy said, you know, if there wasn't something else, the lotion of"
},
{
"end_time": 3527.449,
"index": 149,
"start_time": 3504.48,
"text": " This is not too long after Hubble expansion. The velocities of the galaxies within clusters of galaxies, the thing would have fallen apart if there wasn't something extra, and this was the dark matter, the first indication."
},
{
"end_time": 3538.865,
"index": 150,
"start_time": 3528.643,
"text": " Some colleagues very cleverly said, you know that a galaxy would be unstable"
},
{
"end_time": 3568.166,
"index": 151,
"start_time": 3539.735,
"text": " If there wasn't some kind of dark matter holding it together. So this was an issue of, you know, galaxies. A lot of them were in these spiral forms and those would be unstable. And so the invention was, oh, let's put a halo of something around it to stop this thing going unstable. And then the issue is, what is it?"
},
{
"end_time": 3576.493,
"index": 152,
"start_time": 3568.882,
"text": " Well, the original idea is let's be conventional. Let's just say that there's stars, but stars that are a bit difficult to see."
},
{
"end_time": 3607.022,
"index": 153,
"start_time": 3577.022,
"text": " And, you know, I got into that game. We were especially interested in whether there could be a lot of black holes doing it. It's still possible that black holes could be the dominant source, but we were especially interested in black holes that might have come from an early generation of stars rather than from the ultra early universe. If they come from the ultra early universe, it's like other forms of dark matter. You might call them wimps, except that it would be they're called primordial black holes."
},
{
"end_time": 3634.48,
"index": 154,
"start_time": 3607.022,
"text": " Anyway, there's that possibility. Then there was a period where neutrinos, well, neutrinos do have masses, but it was possible that their masses would be such that they could make the dark matter. And that was extremely exciting, but it made certain predictions, which turned out not to be true. It's still a component of dark matter, but not the dominant one."
},
{
"end_time": 3659.224,
"index": 155,
"start_time": 3634.889,
"text": " and then as we explored it further we said okay well you know it can't be the neutrinos because they were created from the early universe moving too fast so let's deal with a colder variety and that's called cold dark matter and I had a lot of fun exploring all of those possibilities in the"
},
{
"end_time": 3680.794,
"index": 156,
"start_time": 3660.486,
"text": " early eighties, actually through to now. And, you know, then an issue is just like with the dark energy, but even more so, what are the interactions of this stuff? And that manifests itself in a few ways to create it and decouple it."
},
{
"end_time": 3711.544,
"index": 157,
"start_time": 3682.056,
"text": " That requires interaction beyond gravity, and that would be early universe. And there are various things that can be dark matter that arise in the early universe. One of them is these weakly interacting massive particles. The weakly interacting, that's what neutrinos are, they're weakly interacting. It's just that the mass is a bit higher here than the neutrino masses, which is why they turn out to be cold."
},
{
"end_time": 3732.022,
"index": 158,
"start_time": 3711.954,
"text": " But then there are other possibilities that there is this sort of more wave-like dark matter, just to give the term called axioms, that also were emerging at the time and that we folded into the possibilities for the cold dark matter."
},
{
"end_time": 3761.596,
"index": 159,
"start_time": 3732.329,
"text": " So those were kind of the panoply of things that were on the table with a lot of work on the weakly interacting massive particles sort and the different theories that could give rise to them. And then the exciting issue was that if they have interactions, which they must have to have decoupled in the early universe, it means that those same interactions can manifest themselves around us."
},
{
"end_time": 3773.763,
"index": 160,
"start_time": 3762.244,
"text": " And so huge expenditures have occurred to try and directly detect the dark matter, not just gravitationally, but in, for example,"
},
{
"end_time": 3799.053,
"index": 161,
"start_time": 3775.077,
"text": " Now that we're here in Canada, the Sudbury Neutrino Observatory in Sudbury, which is a very deep mine, has got a lot of experiments that are trying to detect the evidence for the dark matter if it's all around us coursing through the earth and making reactions that you can then infer the nature of dark matter."
},
{
"end_time": 3819.07,
"index": 162,
"start_time": 3800.503,
"text": " The executive summary is that after all of this time, we still have the situation where dark matter has an uncertainty in its mass that's 60 orders of magnitude, at least. In other words, we still don't know"
},
{
"end_time": 3847.108,
"index": 163,
"start_time": 3819.701,
"text": " But that doesn't mean that dark matter isn't there. It is there. It's just a question of how do we actually detect it by non-gravitational means? Can you walk us through one of your academic adventures? It's more of how I approach things, which is early on I got enamored by the universe as a collective. I mean, it is, but"
},
{
"end_time": 3866.049,
"index": 164,
"start_time": 3847.534,
"text": " You know that it really got into me so that if you have a slab of matter, let's take this table as an example. And because I did a lot of my original research at the beginning on neutrinos, they're really weakly interacting. So you have neutrinos coming in, they do this little tickling."
},
{
"end_time": 3894.77,
"index": 165,
"start_time": 3867.193,
"text": " And in order to get the response, you think of this entire table as a thing that's responding, even though, you know, we're used to thinking about point light phenomenon, but there is a whole collectivity of things. So that's point one. I love the collective and how, and that's the whole idea of the cosmic web, everything interconnected with everything else. But then the other great passion I have is for entropy."
},
{
"end_time": 3924.206,
"index": 166,
"start_time": 3895.794,
"text": " And entropy, of course, it was a thermodynamic concept that was developed to understand heat engines and all of that. And people have been struggling with entropy for a very long time. And there is this guy, you may have heard of him, Shannon, who was interested in information flowing along channels."
},
{
"end_time": 3928.985,
"index": 167,
"start_time": 3925.077,
"text": " And I'm going to tell this hear that sound."
},
{
"end_time": 3956.032,
"index": 168,
"start_time": 3929.957,
"text": " That's the sweet sound of success with Shopify. Shopify is the all-encompassing commerce platform that's with you from the first flicker of an idea to the moment you realize you're running a global enterprise. Whether it's handcrafted jewelry or high-tech gadgets, Shopify supports you at every point of sale, both online and in person. They streamline the process with the internet's best converting checkout, making it 36% more effective than other leading platforms."
},
{
"end_time": 3975.913,
"index": 169,
"start_time": 3956.032,
"text": " There's also something called Shopify Magic, your AI powered assistant that's like an all-star team member working tirelessly behind the scenes. What I find fascinating about Shopify is how it scales with your ambition. No matter how big you want to grow, Shopify gives you everything you need to take control and take your business to the next level."
},
{
"end_time": 4005.538,
"index": 170,
"start_time": 3975.913,
"text": " Join the ranks of businesses in 175 countries that have made Shopify the backbone of their commerce. Shopify, by the way, powers 10% of all e-commerce in the United States, including huge names like Allbirds, Rothy's, and Brooklynin. If you ever need help, their award-winning support is like having a mentor that's just a click away. Now, are you ready to start your own success story? Sign up for a $1 per month trial period at Shopify.com"
},
{
"end_time": 4026.408,
"index": 171,
"start_time": 4005.538,
"text": " It was a great story. Von Neumann, who was the person that took"
},
{
"end_time": 4051.869,
"index": 172,
"start_time": 4027.432,
"text": " entropy and made it into something that was quantum mechanically compatible. Shannon asked, I have this thing, it's sort of like entropy. What should I call it? I said, just call it entropy. Nobody understands entropy. So my whole career has been trying to understand entropy, which I now think I sort of do."
},
{
"end_time": 4067.892,
"index": 173,
"start_time": 4052.21,
"text": " In a way, I'm still struggling with a full, grand, unified vision of how it relates to everything. Now, why is this getting back into your other question? I can also, of course, expound upon specific"
},
{
"end_time": 4093.148,
"index": 174,
"start_time": 4067.892,
"text": " Whichever route you believe would be more appropriate to answer that question."
},
{
"end_time": 4122.858,
"index": 175,
"start_time": 4094.377,
"text": " Well, I'm going to first of all, give a little anecdote. Theory of everything been around for quite a while. Of course, grand unified theory is what everybody's been striving for. So I was at a conference, many people, including Jim Peebles, Nobel Prize winner, were at a conference on Vancouver Island and playing Tarzan, I swung into"
},
{
"end_time": 4153.302,
"index": 176,
"start_time": 4123.524,
"text": " This will sound crazy, but I swung into a pond, hit my toe on a rock, and it broke, and so I had, you know, had to do some pain pills or something, but I had to still do my talks. So I decided to make this into a cosmic joke and said, I am now going to tell you about my theory of everything, the toe, because that's what it was, T-O-E, the toe, right?"
},
{
"end_time": 4180.845,
"index": 177,
"start_time": 4153.575,
"text": " And so I use the whole spiel to make a theory of the universe associated with my toe being broken and the search for solution and healing of the toe. Anyway, what is this to get across? It's to get across that if you don't have humor in dealing with the quest for toe, then you're not thinking about it right. People are"
},
{
"end_time": 4210.247,
"index": 178,
"start_time": 4181.135,
"text": " What role do higher dimensional manifolds play in structuring the universe? The more important thing than metric is the square root of metric. If you know what I mean, it is called in four dimensions called a fear mind. It is a field. It's a field with labels and the labels are"
},
{
"end_time": 4240.606,
"index": 179,
"start_time": 4211.442,
"text": " Energy. So it's like a gauge field and one of the parts of it is energy. Energy is in that case like a charge. So it then means that that quantity, the fear bind for energy is quite, quite analogous to the photon field, the electromagnetic field for charge. They're the same in structure and how they play out."
},
{
"end_time": 4270.845,
"index": 180,
"start_time": 4241.869,
"text": " Momentum with the three dimensions that we now have of space, they each have their gauge field. They have their minds and they couple in exactly the same way as the photons, even more so they're coupling. It is more closely related to how the gluons that hold things together work."
},
{
"end_time": 4293.217,
"index": 181,
"start_time": 4271.442,
"text": " So when people ask, and that was one of the questions which I think you were trying to get at, is gravity real? And I will tell you that if gravity is very, very similar to all of these other situations, the interesting thing is that you put energy together"
},
{
"end_time": 4320.64,
"index": 182,
"start_time": 4294.377,
"text": " with this fear mind, they couple together tightly and that makes action. And action is, if you look at any particle physics paper, the very first thing they do is they write down the action. The action is the thing that is coupling the forces of action and reaction together"
},
{
"end_time": 4349.548,
"index": 183,
"start_time": 4321.442,
"text": " and it causes the whole process to occur, not unlike yin and yang actually, but you know, one can riff off of these philosophical thoughts, but basically the structure of the universe seems to be that you have something akin to a charge and then the universe or the reservoir or whatever, or the vacuum is responding."
},
{
"end_time": 4379.889,
"index": 184,
"start_time": 4350.128,
"text": " to the charge and the two are tightly coupled together. An interesting question from my perspective now is how tightly they're coupled together. But the main point is that they form this quantity together. So this concept of gravity being so different is, in my view, just people playing in the sandbox, but it's dirty sand or something. Is gravity an emergent property?"
},
{
"end_time": 4408.319,
"index": 185,
"start_time": 4380.435,
"text": " People have played with an attempt to make what is in effect a thermodynamic view. Whether thermodynamic or non-thermodynamics, it's the same thing. It's just that, I mean, again, it's kind of playing with ideas, but in my view, not looking at them as they are. You see, thermodynamics is not just, you know, temperature or something."
},
{
"end_time": 4418.66,
"index": 186,
"start_time": 4408.814,
"text": " fundamental is change and so in any thermodynamic system of which this room is an example it's an open one but it's true"
},
{
"end_time": 4443.695,
"index": 187,
"start_time": 4418.916,
"text": " There are thermodynamic fluctuations all over, and there are gradients in the thermodynamic potentials that cause things to move, for example, from hot to cold. I mean, that's, you know, standard thing. That actually is the story of entropy, which is ultimately related to the story of action"
},
{
"end_time": 4468.456,
"index": 188,
"start_time": 4443.695,
"text": " which is also gradients associated with flowing from here to there. So the second derivative of these things is got all of the aspects or many of the aspects of curvature associated with it. And curvature is one way that we understand how gravity is operating. And so"
},
{
"end_time": 4499.804,
"index": 189,
"start_time": 4470.213,
"text": " What we're dealing with is an attempt to find a language. But the thing is all the languages are all ultimately going to tell us the same thing. It's just that if you hear something in different languages or with different words, you can get further insight. And then some people get locked into just a single language. It is great to develop many ways of looking at the same phenomenon."
},
{
"end_time": 4529.923,
"index": 190,
"start_time": 4500.316,
"text": " And that can allow you to grow. So when people want to say, oh, it's just thermodynamics, I don't think they're thinking about it deeply enough. But if they're saying it's just classical curvature and that gravity is really classical, they're not thinking about it enough. So to me, that is not the mystery. And the structure is not the mystery."
},
{
"end_time": 4560.128,
"index": 191,
"start_time": 4530.674,
"text": " The mystery is perhaps, and I'll get right back to it, is how things emerged and what did they emerge from? I think, you know, I can play around with ideas of what was there that caused emergence. My view is that apart from entropy and phase, which is also called quantum mechanics, it turns out, the log of"
},
{
"end_time": 4588.541,
"index": 192,
"start_time": 4561.391,
"text": " Schrodinger's psi wave function is i times complex action of which the real part is the usual action and the imaginary part is one half of the entropy. That's the universal relationship and at its heart"
},
{
"end_time": 4616.544,
"index": 193,
"start_time": 4588.814,
"text": " is the quantum phenomenon and quantum mechanics is the language of the universe and what it's doing it's saying that I do not I there are forces that are there in Schrodinger's equation for example that try and take the ensemble of possible realizations and make sure that they're spread apart see now I'm getting into where I"
},
{
"end_time": 4646.834,
"index": 194,
"start_time": 4618.797,
"text": " obviously some uncertainty, but that is where we are headed in my view. I mean, I am headed there. And what I am seeing is that everybody's headed there. That is to say, the concept of information and the laws of information, which is quantum information, all quantum, is the underlying architecture of everything. And so when you say is gravity,"
},
{
"end_time": 4676.084,
"index": 195,
"start_time": 4647.108,
"text": " quantum mechanics writ large yes it is but that's because it splits into entropy and action and the way entropy and action work is that it's a product of charge times response to charge so that this is kind of the universal story so then getting back to your questions I haven't forgotten it which is something about spin spins really interesting here and we could riff on that for a while"
},
{
"end_time": 4704.053,
"index": 196,
"start_time": 4676.374,
"text": " But the basic point is that the metric picture is a picture of effectively, even though it's done as metric squared, distance squared, at some level, it is an expression of either action squared or entropy squared. And so, okay, that's interesting."
},
{
"end_time": 4730.794,
"index": 197,
"start_time": 4704.855,
"text": " But it's like, what am I going to say? There is something called the density matrix in quantum mechanics, which encodes all of the information. And it basically is telling you about how a system changes from one form to another. And what we do is we split it up into a product and we call that product the wave function."
},
{
"end_time": 4753.541,
"index": 198,
"start_time": 4731.374,
"text": " So the density is a quadratic combination of wave functions. And what's interesting about that is that it's a complex product. So there are two elements. One is action, which is phase. And then there is the overall density aspect, which is entropy. Entropy is count."
},
{
"end_time": 4777.892,
"index": 199,
"start_time": 4754.241,
"text": " and phase is coherence among counts. So I've taken you to where I am actually spending much of my thinking and how am I doing it? I'm doing it by concrete problems with many of my colleagues around here. So the theory of inflation is a fantastic playground for all of these ideas because"
},
{
"end_time": 4793.08,
"index": 200,
"start_time": 4778.729,
"text": " I want to use something which can actually have observable consequences in order to improve my comprehension of how the universe actually works. So that's what the quest is."
},
{
"end_time": 4819.855,
"index": 201,
"start_time": 4793.558,
"text": " spin metrics. Well the first point is that usually we deal with four dimensions, time, three space. Then within string theory there was an argument for it being, depending upon how you did it, ten dimensions or eleven dimensions. To me every degree of freedom is a dimension which means that it's x, y, z, t"
},
{
"end_time": 4832.073,
"index": 202,
"start_time": 4821.015,
"text": " Zed by the way. And then all the fields. And the fields are dimensions. Why not? And so"
},
{
"end_time": 4856.63,
"index": 203,
"start_time": 4832.5,
"text": " then the issue is is a particle a particle itself a field or is it always a collection and that's an interesting issue. So in my view dimensions are relatively easy to create and destroy and it is not something that people should be overly intimidated by but of course historically we had this path"
},
{
"end_time": 4885.367,
"index": 204,
"start_time": 4856.63,
"text": " which meant that people's minds were kind of frozen in because it takes time for people to adapt and now I'd say that partly because string theory didn't break make the breakthroughs that people had thought because it's complicated I mean it may still be underlying but as a result of that all these bright minds have been pushing at"
},
{
"end_time": 4896.544,
"index": 205,
"start_time": 4886.408,
"text": " All these other questions in physics and it seems to me we're on the cusp of a real breakthrough in what unifies the whole thing together."
},
{
"end_time": 4923.319,
"index": 206,
"start_time": 4897.159,
"text": " is essentially information theory. I mean, and I'm not the only one saying this. It's just that I came to it from a very different route. It's basically been where I've been going all along, but now I see he's doing, he's doing it, she's doing it, she's doing it. That is what is kind of dominating the minds. And then what it blends with is the Google lights in this world because they see the world as information and that's human information."
},
{
"end_time": 4947.039,
"index": 207,
"start_time": 4923.848,
"text": " and human information and physics information, just like with Shannon information along channels and thermodynamic information. It's the same thing. So if we are talking about a theory of everything, a grand unified theory, then it must fundamentally engage in"
},
{
"end_time": 4971.476,
"index": 208,
"start_time": 4948.404,
"text": " Not just the existence of humans that happened on this little planet and, you know, chemical operations of unbelievable complexity all came together to produce this tremendous force of life which just is, doesn't seem to be, well, humans look like they can repress it, but is irrepressible. Life"
},
{
"end_time": 4998.575,
"index": 209,
"start_time": 4971.937,
"text": " everywhere, right? It's amazing how if something goes wrong, Mother Nature comes up with something else, something else, something else. That all has to be fully integrated. And the problem is that it seems so impossible because everything is so complex that how can you make a brand new fight theory? Well, you do it by saying there's principles"
},
{
"end_time": 5029.923,
"index": 210,
"start_time": 5000.077,
"text": " You wanted it to be framed in terms of laws. Law are unclear. I mean, that's the way people used to think about it, right? There's law. There has been, from above, a law has been dictated. But laws are created. Just like things evolve, a law can evolve. A law is an expression of a collective."
},
{
"end_time": 5032.176,
"index": 211,
"start_time": 5031.049,
"text": " Act of Collective"
},
{
"end_time": 5062.363,
"index": 212,
"start_time": 5032.602,
"text": " And so this is one of the interesting things that I'm into now. We call these things effective potentials that define how flows, trajectories, realities change. And usually what you do in physics is you say, let there be this effective potential and then let's look at the consequences. But the view I have is that, yeah, but it feed feeds back."
},
{
"end_time": 5089.48,
"index": 213,
"start_time": 5062.756,
"text": " and the law or the effect of potential changes. And so there is a feedback. Then the question is, how does it all fit together in some TOE? But the most important thing, maybe it's because I'm in my dotage, is that, I mean, this has always been the goal. I think it's everybody's goal. You want to have a grand unified theory that includes all of human phenomenology."
},
{
"end_time": 5109.224,
"index": 214,
"start_time": 5090.299,
"text": " And not just from the point of view of us as kind of mechanical beings, but us as generators of ideas. And does this include consciousness? Yeah, yeah. Well, consciousness writ large, that is to say,"
},
{
"end_time": 5133.865,
"index": 215,
"start_time": 5112.756,
"text": " You know, Plato, Cave, little ideas become capital ideas, capital I. And he would have said it's the capital ideas which are the real truth and the little ideas are just the shadows that are playing out. I'm not"
},
{
"end_time": 5160.316,
"index": 216,
"start_time": 5134.514,
"text": " going to go that far, but the profundity of their thinking was enormous in my view. Everybody else would say the same thing, but it isn't translated into this world as much as it should be. That ideas are the things that have been the great creation. I mean, Mother Nature obviously created them in some sense, but we have something that happened on this planet."
},
{
"end_time": 5185.555,
"index": 217,
"start_time": 5160.725,
"text": " which is the creation of these mega ideas, which required many things. We had to learn writing. We had to learn to speak to each other. We had to, that is all physics. So when you ask what is universe, the universe is you and you and you, and that is the subject. That's a subject of physics, theoretical physics. It's why I got so impassioned by it from the beginning."
},
{
"end_time": 5215.06,
"index": 218,
"start_time": 5186.425,
"text": " because I think I had a glimpse of that's what it should be and could become whether or not I'll get there I don't know or whether you know I'll go laboring off on this except that it is an attempt within you know one being to have a mini grand unification I think that's what everybody is trying to do they're trying to unify their being under maybe not just one capital idea although religion is one capital idea"
},
{
"end_time": 5245.196,
"index": 219,
"start_time": 5215.35,
"text": " Does spirituality play into your life? I believe in everything and nothing. That is my mantra. And that is actually a fundamental statement of the universe. In condensed matter physics, what is fundamental are things called particles and holes. You know, in going back to matter and antimatter, which you wanted to raise earlier of why baryons and not antibaryons."
},
{
"end_time": 5273.951,
"index": 220,
"start_time": 5247.295,
"text": " The holes are the positrons and the particles are the electrons. But it could have been that the positrons are the particles and the holes are the electrons. That is to say, it's totally reciprocal. It's just that something built the symmetry, relatively small force, but something created symmetry. It may sound like I'm escaping,"
},
{
"end_time": 5297.381,
"index": 221,
"start_time": 5274.735,
"text": " what you wanted to get at, which is everything I do is, I don't know, would you use the word spiritual? It is just trying to understand the raison d'etre, why, you know, age of reason, raison d'etre, what are we here for, what am I here for, what is happening, and"
},
{
"end_time": 5323.2,
"index": 222,
"start_time": 5298.336,
"text": " This is unfortunately the situation I'm at right now. The way I see it, it's not unlike ancient Hindu, I guess, that most of the universe writ large may be this kind of fluctuating component in which nothing special is arising and then every now and again"
},
{
"end_time": 5350.657,
"index": 223,
"start_time": 5323.626,
"text": " there is the development of coherence and coherence can breed instability and that's what happened in the alter the universe and a way to say that is that there was a bubble of Hubble parameter that was coherent so instead of it being all sorts of fluctuations like this it developed kind of something where this was connected to this connected to this and then that"
},
{
"end_time": 5373.78,
"index": 224,
"start_time": 5351.834,
"text": " coherence becomes unstable to further development. And so the universe that we can see is that sort of entity in which there's this huge degree of coherence. But if I were, well, I'm not going to bet on this, but I would say that the most natural situation is not to have that"
},
{
"end_time": 5389.36,
"index": 225,
"start_time": 5374.428,
"text": " It is"
},
{
"end_time": 5407.91,
"index": 226,
"start_time": 5389.701,
"text": " There's spirituality, there's more of philosophical spirituality, mathematical physics view of, but trying to integrate all of human phenomenology in the same basic umbrella. Then there was another question, I can't remember what that was."
},
{
"end_time": 5426.92,
"index": 227,
"start_time": 5408.865,
"text": " Ah, well, you know, one of the amazing things is the sheer number of planets that are being observed now. I mean, there was a time when we only had the nine and we had the eight, if you know what I mean with Pluto. But we have this huge panoply. It is"
},
{
"end_time": 5448.763,
"index": 228,
"start_time": 5427.346,
"text": " ubiquitous that there are planets. And at least with the Earth as an example, which is clearly, in my view, special, not just because we're here, but because of this incredible balance of how water came out and is in all of its forms and it's got, you know, the courage is just right, you know, I mean, it's amazing."
},
{
"end_time": 5478.166,
"index": 229,
"start_time": 5449.189,
"text": " But there are so many planets, conditions not unlike that may have happened, and life will choose further paths in order to organize its chemistry. And the organization of chemistry is just so amazing. It's one of the things that intimidates me about trying to do a TOE or granification. It is, you know, how this unbelievable complexity"
},
{
"end_time": 5508.49,
"index": 230,
"start_time": 5478.797,
"text": " emerged from simplicity, and it's playing out. It played out in the early universe with the development of nucleons, then nuclei, then atoms, and then the atoms cohere, but we needed to make complex atoms in the furnace of stars in order to create planets which could then create life. I mean, it's amazing that all of this stuff"
},
{
"end_time": 5534.735,
"index": 231,
"start_time": 5509.48,
"text": " was worked out. And I guess that means that Mother Nature is, you know, working out our equations as we're going, I don't know. And so that's why I don't really have that view. I often use the terminology Mother Nature just to give it not because I'm anthropomorphizing, it's just because"
},
{
"end_time": 5555.111,
"index": 232,
"start_time": 5535.35,
"text": " Things happen that I'm not in control of, and Mother Nature is in control of them and has defined all of us, and it's amazing how she has. Anyway, I would like to find a TOE, so this is getting back to the original thing, but the TOE must have"
},
{
"end_time": 5581.169,
"index": 233,
"start_time": 5555.111,
"text": " What's important to consider for the future? I think that what is probably unstoppable"
},
{
"end_time": 5601.749,
"index": 234,
"start_time": 5582.363,
"text": " is the transcendence of human beings as biological entities. We can see it. We have these devices, but this is now as if it's part of my brain."
},
{
"end_time": 5623.712,
"index": 235,
"start_time": 5602.312,
"text": " The amount of exterior information in this is outrageous and is full connection and it's connecting us. Fortunately, I don't tweet, but it connects everybody and everybody's buzzing and it's making well, you know, the word is the high mentality and all of that."
},
{
"end_time": 5645.811,
"index": 236,
"start_time": 5623.712,
"text": " and it's got pluses and it's got minuses. Obviously their minuses are completely evident in this day and age, but the pluses are there as well. The amount of information that I can get just from this thing right here and now is just outrageous. So then that's the integration of the machine into the being of the human being."
},
{
"end_time": 5665.879,
"index": 237,
"start_time": 5646.391,
"text": " And that's unstoppable, no matter what people say, no matter, you know, Elon Musk and others are saying, Oh, we have to worry about the development of the machine life. I don't think that we can stop that. That's the natural flow of information. And then, you know,"
},
{
"end_time": 5692.927,
"index": 238,
"start_time": 5666.442,
"text": " If that's true, how did that manifest itself with civilizations that are more advanced than us? They will have integrated with machines. I mean, what's the difference between a biological machine and a mechanical machine? And why wouldn't they be intimately related? Because, you know, you can make complex chemical things in a machine. So what is our future?"
},
{
"end_time": 5715.742,
"index": 239,
"start_time": 5693.865,
"text": " That's just impossible. We can't even say it here and now in 2023, by the way, of what things will look like in 2050. I mean, you can't because it's moving so fast. Things are integrating so fast. Our problem is instability. Now, I've extolled the virtues of instability in creating universes."
},
{
"end_time": 5743.951,
"index": 240,
"start_time": 5716.288,
"text": " But instability can also create disasters, and we are moving towards a disaster, which is that this precious planet, I'm just saying what everybody knows, this precious planet is being transformed by human interactions because we are this collective hive that's able to make these transformations, and we've got such a large number of people"
},
{
"end_time": 5762.585,
"index": 241,
"start_time": 5743.951,
"text": " that it requires an incredible amount of us being self-controlled and able to manage as a coherent entity, humanity. So it is, you know, futurologist, what's a futurologist?"
},
{
"end_time": 5785.725,
"index": 242,
"start_time": 5763.217,
"text": " They don't know. Nobody knows because it's all changing so rapidly. I mean, the changes in my life have been amazing. The change that you're seeing is amazing. And then what's coming is either even more amazing or even more disastrous. It's just a question of whether that we can, you know, gain control over the forces that are going to try and split us all apart."
},
{
"end_time": 5803.626,
"index": 243,
"start_time": 5785.725,
"text": " So if we then want to say what about the theory of everything within this context, one way or another, that's what we're going to be moving towards. And I think it'll be based upon information theory, quantum information, because that's the law of the land."
},
{
"end_time": 5830.947,
"index": 244,
"start_time": 5804.138,
"text": " And, you know, is it going to be from how the computer or is it going to be from, you know, one or two people with their blackboards? And the answer is probably how. But this is, in my view, much more creative and fun. And then the other thing that I will fold into that is that"
},
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"end_time": 5856.271,
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"start_time": 5833.063,
"text": " You know, we've all been zooming our life away in the last few years, and that's not a bad way of communicating, but there's something intangible about humans in the same room in relatively small groups interacting together, basically getting intellectually high together with ideas, ideas again, and that"
},
{
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"text": " is precious. And I guess machines can get there. Why wouldn't they? They can enhance it. But it's something which is not reproducible over Zoom. So that gives hope for the biological machine that there is a phenomenology which is occurring, which we do not understand really. Although, of course, many people with religion think they understand it. But that's anyway, so future is murky."
},
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"text": " The podcast is now concluded. Thank you for watching. If you haven't subscribed or clicked on that like button, now would be a great time to do so as each subscribe and like helps YouTube push this content to more people. Also, I recently found out that external links count plenty toward the algorithm, which means that when you share on Twitter, on Facebook, on Reddit, etc."
},
{
"end_time": 5939.343,
"index": 248,
"start_time": 5912.398,
"text": " It shows YouTube that people are talking about this outside of YouTube, which in turn greatly aids the distribution on YouTube as well. If you'd like to support more conversations like this, then do consider visiting theories of everything dot org. Again, it's support from the sponsors and you that allow me to work on toe full time. You get early access to ad free audio episodes there as well. Every dollar helps far more than you may think. Either way, your viewership is generosity enough. Thank you."
}
]
}No transcript available.