 So, I think it's kind of fitting that this talk comes after the previous talk, because a lot of what I'm going to talk about is I use this visualization that artists have rendered. There's a lot of astronomical art in this talk. And so, what we're going to step through is that the laws of nature and the initial positions change a little bit so that the density of the universe is so small that atoms never interact with each other or that there are no heavy elements of essentially no chemistry. And so, this is a puzzle of any sciences. And so, I'm going to present one hypothesis of what this might mean, it's a bit controversial. And so, the starting point for this talk is about how the universe evolved from when it was the second world. We actually have observations or indications of what the universe looked like, just a second world. And all of them made sense today. So, we can roughly say what happened over that few 14 billion year time span. And one of the reasons we can do this is that if you take a telescope and that's sensitive to one centimeter of light, so our eyes can see hundreds of nanometer of light, so much shorter, 10,000 times shorter light wavelengths. Then, so if you look at these much longer wavelengths, the universe is dominated at these wavelengths by radiation from when the universe was a hot plasma from the big bang. And in fact, there's 100 times more energy than this one centimeter of band than there is in all other bands, all other weight bands. All radiation emitted by stars in the history of the universe is less than a hundredth of the energy that we see at one centimeter when we look at the sky. And so, we've taken a picture of this because the cosmologists have really studied this radiation, looked at different directions, and then, and this is what it looks like. And so, this is a 2D projection of this cosmic microwave background. And so, this projection is very similar to, like if you took the globe, the Earth, the Earth is here, and if I made a 2D projection, the Americas would be here, and Europe, and Asia's here, and Africa's there, and you can turn that around, you can look out at the sky and look at different angles, and this is what you see. So, this is, again, a 2D projection of a surface, a spherical surface, and then every pixel here is telling us about how much radiation we're getting from different locations on the sky, and you can see that there are differences. So, the red, there's a little bit of less radiation, and the blue, there's a little bit more, and these differences are telling us that there were improved genealogies in this radiation that we're seeing, and this radiation is coming from the universe that was 400,000 years old, and so there's small and huge in the 80s in the universe, small fluctuations in the amount of matter from place to place, and the size of these fluctuations are part of 10,000, so the contrast in this picture has really been dialed up so that we can see the fluctuations, and these are the fluctuations that grow into us. And so, one thing that pathologists try to do is they try to model how these fluctuations grow. We think we know the laws of physics that have all been forward, so we put this on a giant computer, super computer, and we hit go, starting with these little matter fluctuations from place to place that we see from when the universe was 400,000 years old, and we hit go, and gravity does its job, it's mostly gravity, and it causes regions that have more matter to get denser and denser, it's the pool of gravity larger when there's more matter, and the regions that have the most matter, those are what become galaxies, and we run these simulations, and you get galaxies, and you get stars, and you don't resolve everything, and so if we think we had even bigger super computers, we get planets, and so we kind of know the story from how we map from these fluctuations until today, but in order for this story to work, it seems like the conditions for the universe that allowed galaxies to happen seem very true, and so that's the theme of this talk, and so just to kind of illustrate, so something's at these fluctuations, I'm gonna mention what we think it is later on, but since there's these fluctuations in the universe that are 400,000 years old, and then you have gravity, but if the fluctuations aren't big enough, so if they're too small, then gravity can't do enough by today, you don't have anything in the universe. If the fluctuations are a little bit too big, and I should say, if they're a little small, and even the effect of tin would totally get rid of all galaxies, the effect of a few big difference, so if they're a little bit smaller, nothing. If they're 10 times bigger, the universe becomes a lot more chaotic, well, probably a lot harder for life to exist. If they're 100 times bigger, these two bombs become black holes, and so these fluctuations were set up so that gravity could become us, and they couldn't be much different. It's also true that we would not exist if there wasn't something called dark matter. That might sound really crazy, because we don't even know what dark matter is. We have ideas, probably some particles that haven't yet produced a lab, but the thing that makes dark matter special is that it doesn't respond, if there's radiation in the universe, it is not pulled around by that radiation, whereas everything that we know, electron, nuclei, the radiation just pulls them around, and there's so much radiation in the universe. So when the universe was 100,000 years old, there's a much energy in radiation as there is in everything else. The radiation just pulled everything around, and if you didn't have something to lay a base or to hold on to things, if you didn't have dark matter, then there wouldn't be any fluctuations, and so you wouldn't have galaxies. So we owe our existence in part to the fact that most of the matter in the universe is the stuff called dark matter. That's also weird. Okay, another coincidence is that if you're taking a physics class, you may have learned that there's this symmetry, that for every particle, there's an anti-particle, and it's bad. If I had a gram of stuff, I'm not gonna, I have a really bad joke here, so I don't know what I mean. I have a gram of stuff, and I bring matter and anti-matter together. That's as much as the approach to what I think we're all. So if we had matter and anti-matter in this room, it would be really, really, really bad. But somehow, something broke this symmetry in the early universe, and made it so that there was a billion asymmetries between matter and anti-matter, and then everything, all of the anti-matter, found matter, annihilated, and we were just left with the matter, and then we could exist. But why did this happen? I mean, we don't know, but we needed it to happen. Okay, next coincidence, and I should also say, I'm just really skimming the surface on it. I'm a cosmologist, and so I'm giving you some of the cosmology coincidences, but there are, it's kind of ridiculous how many coincidences there are for life. And so, okay, next, I told you that gravity, I start with fluctuations, gravity makes galaxies. This is not quite right. So the gravity makes big balls of gas in this situation. Why don't we dye a gas bulb in the universe? What's gravity is to this job? And so the reason that there's no dark, so any gas bulb, or dark matter, and there's a gas, the gas we know, but the gas we know has a really special property that it can emit photons, and as it loses energy, it will cool, and it will contract, and then it gets a lot denser than the dark matter, and that's why galaxies are made out of gas. They're not made out of dark matter. But in order for gas to be able to radiate, it turns out that you need a light particle, so we have electrons, and we have a nuclei in the universe, and that's most of stuff, and the electrons are really good at radiating because they're really light, but you also need something really heavy, you need something that's a thousand times heavier, so that's where the proton, if they weren't, we don't know why they're a thousand times different, it's not like a, well, we don't, physics can't predict what the masses of these particles, these are just parameters that we haven't figured out how to understand, but somehow it was tuned so that the gas can cool and form galaxies. I think, at the very least, you need a galaxy to have one, but it's just too diffuse otherwise. All right, okay, next. So this gas is cooling, and it cools into this, and I'll tell you all the why this galaxies are this, big gas ball, and it's rotating a little bit, but then as it, Matt, you need a light. Am I? This is dangerous, I should have said that. Contribution and angular momentum. Start with these fluctuations in the early universe, and conservation and angular momentum can exist that with light galaxies. And it says, all of this physics is super easy. And then, and the solar mass scale is, and this is the scale where you just, if things were much smaller than the solar mass, and all of these things that are the sizes of stars, if the fragments were a lot smaller, you wouldn't have fusion, and you wouldn't have stars powering light. And also, you need tensile mass things, because the tensile mass things make heavy elements. The heavy elements are really important, we're not. I didn't tell you, but the universe starts off with just hydrogen and helium, so you need to form something larger than the heavier than the hydrogen and helium. And coincidentally, there's like a miracle that carbon can be even produced in the universe, but that's what this works. And then, okay, so then you have these, and why are tensile mass things, so they make heavy elements, and then they explode, and then supernova. And like as far as we can tell, supernova, like even in our universe, we can barely get them to explode, and it involves like so much physics, it involves something called a neutrino, like which isn't important for anything else, but supernova's just in our universe, supernova wouldn't explode, and we wouldn't have anything but hydrogen and helium, most of the time. Somehow our universe knew that it needed neutrinos, so that stars could explode, and then you need that for a term. Okay, so now, we're getting kind of to the end, but okay, so then, so it turns out that there's another thing in the universe, so there's dark matter, and it's just one dark thing, and dark energy, and then there's another dark thing. Most of the energy that's in the universe is in dark matter and dark energy, so we like, I mean, maybe cosmologists kind of suck, but we don't know what it's like, maybe we kind of have ideas, but, you know. But what we think dark energy is, is energy in the vacuum, and so then we go and we calculate how much energy in the vacuum there should be, and we make a small mistake, and it turns out our mistake is off by a factor of 10 to the 120, and so, somehow the vacuum energy is much, much, much, much, much smaller, that's a big number, which is not everything, it makes the universe expand a lot faster, and so if there were a factor of few more dark energy structure would form, you wouldn't have galaxies, which is weird, so it's not, and so strength theorists have come up with some solution to this, which is that they find that the typical amplitude of dark energy in the universe is 120 times, 10 to the 120 times larger than in our part of the universe, but that we live in part of the universe with 10 to the minus 120, at least unlikely, so that the end of dark energy fluctuates from place to place, and so then, and so maybe this is pointing to the universe being much bigger, and so that brings me to this hypothesis, maybe the universe is much, much larger than it is observed, and the reason that things seem so fine tuned is that we can only exist in a very special part of it, and at some level, this doesn't seem that controversial, it makes sense that we're not existing outside of Earth's atmosphere, we're outside of our galaxy. The Earth's atmosphere, late Earth, is just a very, very, very small fraction of the universe, the universe is 14 billion light years across, Earth is a very small fraction of a light year, very, very, very, very small. I would do that regulation, but I wouldn't sense it here. So, yeah, so maybe on large scales in our universe, extreme theorists think that this might be the case, that in their theories this work kind of happens, that on large scales, other things, a matter of dark matter, a matter of dark energy, like a matter of, in matter, in matter, all of these change, and we live in this really special spot. And I would say that if you've been, in addition to everything that I've shown you, I think there's some stronger evidence that this is the case. And so we started off talking about these density fluctuations in the early universe. 400,000 year old universe, we see these small density fluctuations, and it turns out that cosmologists have a theory for what, and I would say it's a very successful theory for what created these density fluctuations. And in particular, the theory is something that's called inflation, it's probably one of the most profound theories out there, in my opinion. And so the story kind of goes that there was some particle in the early universe that printed these fluctuations, involves quantum mechanics and stuff like that. But it really explains the properties of these density fluctuations we see in the universe, it's really successful. But the way this theory works, it predicts that the universe is very, very likely, much, much, much, much larger than our universe. And in fact, in many, many versions of inflation, it predicts that not only is the universe much, much larger than anything we can observe, but it predicts that the universe varies from place to place. Most parts of the universe are expanding much faster than our universe, apart of the universe, to no galaxy, to no anything. And so I think it's not crazy to think that our universe is much, much larger than this. Okay. Okay. Okay. They're interacting. You might not know this, but matter and vacuum, and in like nanoseconds, they're even smaller, are annihilating everywhere. But yes, they interact and they annihilate. And so they affect the anti particle of an electron, it's called a positron, and they have opposite charges, so they just pull each other, they pull each other together and boom. And this is much more, you get all mc squared of energy. This is much more efficient than fusion or fusion. Yeah, that's a good question. I don't know if there's a precise definition, but if I get it as the universe being, that the properties of our universe, the physical laws are different in other parts of space, space time. And so everywhere we look, universe looks the same, the laws of physics look the same, but the laws of physics seem very fine tuned. And so this is an explanation for why, there were many parts in the universe, then you can exist in that fine, then the reason we find ourselves in this fine tuned location is because that's the only place we can exist. But everywhere else, life can't exist. So that's the hypothesis. So that's the argument why it might, of all day universe, of all day universe might be likely for it, to explain these coincidences. Yeah, so I already talked about these coincidences that were so small of a chance that we were getting here. But then I also thought that the universe was practically infinite. So I wanted to know if in a practically infinite universe that maybe existed for, I don't know, maybe forever, isn't it? Don't these coincidences have to occur at a certain point? Are they bound to occur? So this is the thing we don't know. We don't know what the size. So we can only see things that have been traveling through the age of the universe. So roughly, we can see you're 14 billion light years away. And that's big, maybe, but we don't know. Like is it, or does it just terminate like on kind of that scale? And so this is, I think the subtlety is not only that this is predicting a much, much bigger universe than what we see, but that it varies from place to place so that there are regions where life can exist. Back there. Yeah, this is a really good question. This is the principal reason why people hate this theory. It is essentially a theory arguing that that we are not going to be able to understand everything and some things are like the electron mass and the value of the amount of vacuum energy and the dark energy is a kind of a random thing that we should be able to understand everything. Like I think that that has been the hope of physicists, but I don't think it's any reason to expect that nature will be that kind of thing. I guess I've totally forgotten to repeat questions. So the question is something like, are there other big beings in the universe in this multi-verse picture? And so I'd first like to say that, okay, what is the big bang? The big bang is that it's essentially, maybe it's a bit of a misnomer. And it's a statement that we had this hot plasma in the early universe that and everything is expanding with time. And so if you extrapolate back, you have some kind of singularity, but we don't know how far back you can extrapolate. Inflation kind of naturally happens when the universe is something like 10 to the minus 30 seconds, so maybe you can extrapolate back to that point. At some point, like 10 to the minus 34 or 40 years, I forget, then we don't even know how to calculate this. There are many strings here. So yeah, I guess in essence, there are big things happening in different regions of time in this picture for reasons that maybe I'm not gonna, I won't go in two things, I think it's gonna be a little bit too much, but yeah, yeah, definitely, all right. So I would like to say that I'm representing that hypothesis and I don't, I'll repeat the question and then I'll say this. No, sorry, I'm really terrible at repeating the question. So the question is, do I ascribe to the theory of there being infinite number of places, multi-verse number of universes, or is there a finite number? So I think this is a hypothesis that for what, the multi-verse theory that I presented that, and this is not my, I would also say that I usually work on more mundane pathologies in this, but the other way, I'm writing a paper, can I just say like, what, the, so the, so, I don't know. The, like, please just say one other thing. There are many different places in this multi-verse. I think there's called Bacchua. That's based on this cosmological constant. So there are theories that you need to be greater than some amount, and the claim is that there are tens of 500. Sorry, I was looking for seven. Yeah. All right, all right, yeah. 42. 42, yeah, okay. Yeah. Horses or particles from parallel, or? Yeah, so there's a question of whether there are theories of nature that interpret dark energy or dark matter as forces or particles in some other dimension. And the answer is yes. And in particular, I'm not a string theorist, but string theorists like to, there could be some dimension that we just can't access that's very close to us. And in that other dimension, that we're not able to access, there could be some other particles that, and like, so this is called like, the cloud to climb. Space and time that's separating the universes, does that kind of take away the idea? Sorry, you trailed off to the like that. So just, you mentioned that in between the universe, it's just a space and time. Is that like, take away like the idea of like, you know, kind of folding the tree. Um, I guess, so I'm not gonna repeat the question only because I don't know the answer. I mean, I don't have a great picture for one. This looks like other than, it would look different than our universe. All right, keep going. Two more? Okay. Two. Are these space? Yeah, these spaces are connected. The question was, are the spaces in this multiverse connected? And the answer is yes. I'm a nerd, but I guess I haven't gotten into that either. I've been really upset by the quality of some of the Star Wars movies. Yeah, it is. Star Wars movies, right? Joyce, is there a barrier between the space and it being in the universe? All of these questions around, even starting with the gentlemen's over there, are like, are related and it depends on the picture. So in the inflation picture, most of the other places in the universe, those of the, they kind of need to be, so this is just, this is the multiverse from that occurs in inflation. The, most of the places in the universe are expanding much, much faster than our place in the universe. And so they differ in that respect. But they're connected, but you can never get to them because they're expanding away from you so quickly. That's right, so they are, like a way of saying that is our horizon, we can see out to, or the light can travel some distance and our horizon never intersects these regions, typically. But there are people who write papers about these other pockets of the universe colliding with ours, and you could, in the C and B, the first picture I showed you, you get this is going back to the universe. Nevermind. So people look for collisions of some bubble universe of ours. They look, and it should look like a, like a, like a, like a, a, a, a, a, a, a short game, something like that, in this, in this cosmic way going back around. And there's no indication that this is the case, although this is also, is there, the, the predictions whether that this should occur are, are, are, are sketched, so. Statistically, another part of our multiverse intelligent life. So the question is how probable is it that another part of our universe has intelligent life? And so the, the, my answer would be, well, first in our universe, there are, there are 10 billion stars in our galaxy. A lot of these have planets. There are, there are a trillion galaxies that we can see. As of then, as of that's, that's already a lot of planets. And so I, so I would say it already differs very likely. Like I would be really surprised if there wasn't like another part. But then I think the same probably goes here. Like if, there's no reason to think that we're unique. And so there are, there are other places in our multiverse that, that, that, that I would expect that way. I think it would, it would, it would be just too fine too. Like there's no way for us to do the whole thing. Well, the only reason in the multiverse, I never thought I'd say that. That, that has like, right, that's the last question. Thank you. Thank you, sir. Thank you all so much for coming. We'll see you next month, December 20th for episode six of Promise Against Cosmos. See you then.