 It's my pleasure this afternoon to introduce one of our own alums from our physics department and Returning as our visiting assistant professor in physics Daniel Berg to introduce Professor Krause Okay, I'm really excited to be up here because I'm a little strange in that I really enjoy a little bit of awkwardness And I have a feeling that This is going to induce a little bit of awkwardness and excitement in all of us this talk and discussion to follow Some of the questions that we are here to ask that we've been talking about is why is there something rather than nothing and if space is infinite, what is it expanding into and Is the ideas of multiverse is a reality and why does any of this matter? Our innate human curiosity has fueled our journey of scientific understanding and is why you're all here today We seek to answer the larger questions of who we are How we got here and if we are unique or rather, what is our place in this universe? the significance of these questions is profound and it links us to the greater cosmos as Dr. Filipenko talked about yesterday in 1998 There were published observations of type 1 supernova that suggested the expansion of the universe is accelerating Dr. Lawrence Krauss was one of the first physicists to suggest that space is composed of dark energy making up approximately 70% of our universe by volume Although we cannot see dark matter or dark energy directly Many of the scientists that are here today and others around the world are looking at its effects on the visible universe Krauss has gone further by examining our current understanding of the universe in order to ascertain how we got here By a universe full of stuff such as our own How could it result from nothing by natural processes? So although we have many spirited young speakers with us today and even younger Lawrence Krauss received his bachelor in physics and mathematics from Carlton University in Ottawa and his PhD in physics from the Massachusetts Institute of Technology He is currently a foundation professor and director of origins initiative at Arizona State University He has published more than 200 scientific articles many about the physics and astrophysics that we're discussing here Krauss has also authored several celebrated books, which you can get in the bookmark across the way hand-tint Including some really great books on the fear of physics about Star Trek About the atom and a universe from nothing Further he's a recipient of numerous awards including the American Association for the Advancement of Sciences award for public understanding of science and technology and The Julius Edgar Linienfeld Prize of American Physical Society He was even nominated for a Grammy Award for his liner notes for the Teller CD of music from Star Trek This guy has literally done everything He has even received the Colbert bump for his book a universe from nothing in his abundant spare time He has been working on and created a documentary film called the unbelievers with fellow renowned skeptic atheist and Evolutionary biologist Richard Dawkins, which is currently being released in limited cities, and I hope to eventually see The film follows Krauss and Dawkins as they speak publicly around the globe about the importance of science and reason in the modern world As a science educator and advocate Krauss is also an active and respected member of the skeptics community I bring this up because I first heard Lawrence speak at the amazing meeting in Las Vegas in 2011 After watching him stand up to a very a very spirited discussion with Neil deGrasse Tyson on the future of manned space missions I was a little intimidated But more so excited and challenged by the controversial ideas Krauss presented as you may have noticed already during this conference He is not afraid to voice his opinion Confront disagreement or initiate that provoking discussion from His exceptional taste in shoes, which you'll get to see in a moment To being quoted via tweet by Miley Cyrus or to his impressive IMDb webpage, I cannot think of a more interesting passionate or accomplished scientist to engage us all on the universe and its limits To quote Lawrence Krauss himself, so don't get mad at me The amazing thing is that every atom in your body came from a star that exploded and that the atoms in your left hand Probably came from a different star than your right hand It really is the most poetic thing. I know about physics. You are all stardust You can't be here if stars hadn't exploded because the elements the carbon nitrogen oxygen iron all the things that matter for evolution Weren't created at the beginning of the time They were created in the nuclear furnaces of stars and the only way they could get into your body is if those stars were kind enough to explode So forget Jesus the stars died so that you could be here today whether that quote Inspired you and left that ah induced tingling feeling that I get in my body or it rocked the boat for you a bit I Cannot wait to see what Lawrence shakes up today and the important discussions that will ensue It is my great pleasure to introduce to you the sixth speaker of the 49th annual Nobel conference and his talk about a universe from nothing As he challenges what you may think you know about the universe and its origins and ignite your imagination of what lies ahead Please help me in welcoming a rock star of my scientific world a man who is obsessed with nothing Professor Lawrence Krause That work. Thank you. I'll have Thank you. Thank you. Danielle. Thank you everyone here Chuck and everyone else for organizing this. It's been a it's been Remarkable first thing I'm gonna do is get off the podium because I don't like podiums. I I I want to change thank Chuck at the well first of all actually as many who can know I like to try and one up my colleague Frank will check whenever I can and And I want to point out that that this is better than his because I won't actually take off my my shirt during the talk and So thanks to that to Chuck I want to thank him for for allowing me to speak 6th after two talks on cosmology So that the universe to talk with the universe from nothing I kind of thought would there be nothing left to talk about and I figured that's what he would he would want me to do But I'm gonna try it. I'm gonna try anyway, and I think actually I've thought about there'll be some overlap But but but Alex's talk and George's talk allowed me to build I think on on some things that they said and put them together in a way that I hope will will enhance things and And really what I want to do and then this is really what I think all the speakers has tried to do It's one of my favorite quotes that I began at least one of my books with it. I'm also by the way not gonna use that stupid arrow Because because I've learned that actually all I checked empirically that you can actually see the screens from the back of the room So if I do this in this you can actually see what I'm doing. So it's easier for me to do that But really the most exciting part of any mystery is getting to the starting point and hopefully what we've all done and what Will do today and yesterday is get you to the starting point because they're wonderful mysteries And they're young people here who are gonna carry on science the next generation It's those mysteries that should inspire you the science We often too often teach science as if it was especially physics as if it was done two hundred years ago by dead white men and And it's not they're full of mysteries And and I hope that that you will be inspired to solve the problems that we've been talking about here today In any case, okay, so let's begin the question that that Danielle mentioned is an interesting question and Why is there something rather than nothing? It's really inspired humanity since humanity has been thinking about that How did we get a universe? How did everything we see get here? And it's been the source of of constant speculation from religion to philosophy and science and and and What's amazing is that science is beginning to at least be able to confront a version of that question And that does upset some people as as we'll undoubtedly talk about But there but what I want to show you is the amazing Results that that couldn't have been talked about at a Nobel symposium 30 years ago We've really it's been a revolution in our understanding of the universe It's allowed us the temerity to begin to address these questions not answer them but address them And I think that's what makes it so exciting Okay, so there are two ways to answer that question one way is to write a book that begins like this doesn't tell you anything about anything and Now Frank may think I'm being provocative and and but of course I'm really happy to see that my good friend George Coyne agrees with me about this and I'm I really hate always hesitate to say that George Coyne is a good friend of mine because I'm always worried he'll be excommunicated but But he is and But really if we want to learn about the universe the way is not to not to think about a book Written before we even knew the earth orbited the Sun but to ask the universe and you've seen this image a lot in different forms The Hubble steep field but the way if we want to learn about how the universe might have come into being and ask those questions because because it did come into being and It's a physical universe and if we want to address these questions physically We have to look at the universe and ask the questions and that's what I want to talk about and the universe has given us has changed our picture of Everything more in the last 30 years and perhaps the last 2000 and it's an incredibly exciting time so Alex did a talked a lot about Hubble and the expanding universe. I won't there are two things I want to add to what he did One is he didn't mention Hubble's most important characteristic as far as I can tell for the young people here, especially Because Hubble gives me hope for humanity Because he began life as a lawyer and then became an astronomer and so for all of you Who are thinking in a law school? There's hope for you After that, that's the first thing the second thing is especially with the questions after George's talk And and George happily once again showing us at the Senate. We're at the center of the universe I thought I might also complement what Alex did a little bit to give you a different way of understanding that we're not and and this is useful I think because I often tell students that in physics, you know the first time you see something you don't understand it And the second time you see you say I've seen that before and so There's a lot of familiarity that helps with that regard so so anyway, this is so Alex was kind enough to give me the slide the version of the slide he showed before this is what Hubble discovered which is that everything's moving away from us and And we codified in some relationship that the velocity of objects is proportional to their distance and That makes it look like with the center of the universe and he gave one example But I'd like to give a different one which I think for me at least Helps me understand that that this doesn't tell us where the center of the universe It tells us that the universe is uniformly expanding now the real problem is myopia. We are actually stuck in our universe Well, most of us are the Republican Party clearly isn't today, but but You can Anyway, so the way to see this is to get outside of our universe and and I can draw a universe We're outside of here's a universe that has galaxies at regular intervals and just so you don't feel bad over here I'll point these and And you can see if you're standing outside of that universe that that it's a little bit later It's expanded the distance between all the galaxies is bigger and the question is what would you see if you lived in that universe? It's quite simple. Just pick a galaxy any galaxy say that one and to see what you'd see Just we just superimpose this image on top of this one placing that galaxy on top of itself. What do you see? Exactly what Hubble saw and the point is it doesn't matter what galaxy you pick that there's the image that Hubble saw Let's take another galaxy put it on top itself Everywhere you are everything is moving away from you and that's exactly what Hubble saw So what Hubble told us is there is no center of the universe or every place is a center It depends on how you like to think about things But but really what's important is that the universe is expanding and that the fact that the universe is expanding changed everything again, we It's so permeate the public consciousness That the universe began well except in certain states like Arkansas and Ohio and a few others that it began 13.8 billion years ago But the fact that universe began in a big bang is so much a part of popular culture that we forget that Less than a human lifetime ago. That was not the conventional wisdom in science The conventional wisdom in science and when when Einstein was developing general relativity was that the universe was static and eternal They've been around forever and it would be around forever It seemed reasonable when you looked out at the sky and so the universe having a beginning changed everything in science and also obviously in philosophy and religion and It changed everything in science Also, because if the universe was dynamical the natural next question was if the universe had a beginning How will it end and Alex talked a little bit about that and I'll talk more about it because if the universe is expanding the Natural question then becomes will that expansion stop and re-collapse in the in the big crunch or something else and The answer to that question depends it turns out remarkably The only way to actually consistently describe an expanding universe is to use the laws of general relativity Because general relativity is the first theory to describe not just how things move in the universe in space and time But how space and time themselves dynamically respond and what Einstein told us is that space and time Dynamically respond to the presence of matter and energy like curving and and and potentially expanding and so what Einstein told us is that the future of the universe depends upon how space responds to the presence of matter and How much matter there is and we you know we present pictures of that as an up to a picture It's always hard to do because it turns out our universe because matter can Because space responds to matter space can curve in the presence of matter and that means it turns out and Frank gave a beautiful Talk on geometry that our universe can exist in one of three different geometries So-called open closed or flat Now we it's hard to picture these as Frank was pointing out It's hard to picture a four-dimensional universe in general It's hard to picture a curved three-dimensional universe because we live in in a three-dimensional universe So we draw pictures two-dimensional pictures to guide the eye, but that's all they are So here it turns out a two-dimensions the same thing you can have a closed Universe which is a surface of a sphere in two dimensions a flat universe like a piece of paper that's flat or a open universe like a like a saddle But these just guide the eye in a real closed universe We're talking about the curvature of three-dimensional space, and you can't picture that Easily you can write it down mathematically you can we can talk about what it would seem like for example It's such a universe if you look far enough in that direction you'd see the back of your head Okay, so we could talk about that and it all sounds very nice But what's really interesting and the reason physicists cared about that in fact the reason I got into cosmology So I got into cosmology because I wanted to be the first one to know how the universe would end it seemed like a good idea at the time and The answer depends upon Based on general relativity on the amount of matter Because if there's enough matter and we live in a matter-dominated universe alone Then if you if you have enough matter to make a closed universe while that looks nice And it's wonderful to talk about a cocktail party the important thing is in a matter-dominated universe The universe will expand to a maximum size and then collapse in an open universe It'll go on expanding forever and a flat universe is the boundary between the two where it slows down and never quite stops That's and so the real question of 20th century cosmology became which universe do we live in? Because then we know what the future will be and if we want to know which universe we live in we have to know how much stuff There is very simply. We just have to weigh the universe. It's a homework exercise and and that really weighing the universe became the business of 20th century cosmology and I've written books about it and And you can talk about it for a long time But like many things a picture is worth a thousand words But I want to to give you a perspective we have weighed the universe and I'll show you the results To give you a perspective on this. I want to take you back a little time in history. I think especially for the students Some of you will become scientists and you'll submit articles to journals like science and you'll be rejected Okay, and I just want to tell you it you shouldn't wait I want to take you back to a kindler gentler time. It's a much more difficult time than it used to be so I want to take you back to 1936 and there was a there was an article that came out in science magazine called lens-like action of a star by the deviation of light in a gravitational field and Here's how it began Some time ago R. W. Mandel paid me a visit and asked me to publish the results of a little calculation Which I had made it his request this note complies with his wish Okay, try that now and see what happens. Okay, so I mean and now the the author had credentials His name was Albert Einstein. So it kind of helped but But what Einstein published there was the results of a calculation that he thought was completely unimportant So unimportant he wouldn't have published it otherwise he published results of a calculation He'd earlier showed that light curved around a massive object. That's what made him famous as was pointed out but He realized if you had a massive enough object and he had a source of light behind that massive object then the light Could curve in both directions and come back and converge and the object could act like a lens It could magnify objects like my glasses do for nearby objects or if I had a cut glass goblet Which you don't have here. I could look through through that and I'd see many images of you But he thought it would never be observable. He thought it was totally unimportant In fact, it's kind of interesting if you look at his calculation and from his notebooks in 1936 You also realize that this is the calculation on which that space that actually he done exactly the same calculation in 1912 in his notebooks from 1912. He just forgot he'd done it Okay, and my favorite part of this whole story is the note. He wrote the editor afterwards He said let me also. Thank you for your cooperation with the little publication which mr. Mandel squeezed out of me. It is a little value, but it makes the poor guy happy Okay, that's how science is done. Okay, and the great thing of course is he was totally wrong It's not a little value It's the way we weigh the universe and here is the picture of the very phenomena that Einstein said would never be Observable and and I showed a different one, but this is this is relevant This is an amazing picture because it's a picture of gravitational lensing It's a picture that results from the fact that space is curved So you don't have to be a rocket scientist as as Sam Ting would say to to See that you know, this is a cluster of galaxies and as George pointed out Clusters of galaxies are the largest bound objects in the universe Maybe almost 10 million light years across from side to side They're the biggest bound objects in the universe and anything that can fall into anything Will fall into a cluster so if you can weigh the clusters you can weigh the universe and And every and like many of the images you've seen before every every dot in this picture is a galaxy Not a star each of these galaxies contains hundreds of billions of stars. This is a cluster. That's five billion light years away Five billion light years away. So the light from those stars left before the earth even formed Okay, and by similar token if if if there were beings on that cluster that looked at us And saw the light that's happening now we'd long be gone by the same time they watched And in fact most of the stars in this image may not even exist anymore They may have ended their lives and the civilizations that may have existed around them and had meetings like this are no longer And I mean that's I think that's really important because we may talk about spirituality But real this is real spirituality this when you look at this images like this They they inspire you in ways that nothing else I know off to inspire But in any case as inspiring as that is the really important thing is you don't have to be a rocket scientist to see these blue things Here are different and what they are are multiple images of a single galaxy Located five billion light years behind that cluster a galaxy that's so faint that without the magnification of that cluster We probably wouldn't have even seen it, but not as you're only just one image There are many images because the cluster as a clutch glass goblet would splits up the light it bends in many different directions So this is proof if you wish that space is curved We don't but we don't need the proof because we we know general relativity works We tested many other ways so now as Frank talked about we can now use it to test other things And so we use general relativity and the point is if we now that we know general relativity works We can use it to weigh this cluster because you can ask how much mass must there be in that cluster And where is it distributed in order to produce the image we get now? That's a complicated thing called a mathematical inversion It's relatively complicated to do but you can do it and and Tony Tyson and others a long time ago at Bell Labs did it and Here is this cluster, and this is where the mass is as Show it in the end as extracted from in order to produce the image that was seen The mass must lie in this in this direction here in this way, and of course what you can see is spikes where the galaxies are But really what's most important is you see a huge mountain of stuff where the galaxies aren't There's 40 times as much mass in this picture as meets the eye Most of the mass is where the stuff isn't shining and in fact around each galaxy There are little mountains as well most of the mass associated with each galaxy is not visible And that's the stuff with that physicists with their great linguistic perspicacity have called dark matter And so we know that there's 40 times as much stuff in here, and it's dark It doesn't shine but what makes it particularly exciting and one of the reasons we were talking about it is for reasons I won't have time to go into maybe in the question period. I don't know We are we have many good reasons to believe not to believe to understand That there's too much stuff there to be accounted for all by all the protons and neutrons We know are in the universe We know how many protons and neutrons are in the universe and there's ten times more of this stuff That is allowed by that so that tells us that it's probably not protons and neutrons That means it's some new type of elementary particle of the type we talked about and Tara was talking about discovering at the large adder on collider And what makes that particularly exciting is that means we don't have to just look out there through telescopes for it It's in this room. It's going right through your bodies as you nod off after lunch during this lecture And that means we can build experiments to look for it. We don't have to use telescopes And where do we build the experiments not here because right now we're all being bombarded by cosmic rays That would if you put an experiment here would it would just have too much noise you go deep underground Because most of the cosmic rays will be absorbed But these dark matter particles because we think they interact so weakly most of them will go right through the earth without even knowing It was there and there are experiments being built around the world To look for that actually this is it takes me back This is actually based on a proposal of Frank and I made 25 years ago or so and then we didn't have to build it So But this is a this is a dark matter detector. It's actually located in Minnesota Deep underground and it's kind of simple You just take a little bit of germanium here and cool it down to about one one thousandth of a degree above absolute zero Which is what I'm told it is here in in the winter and And and then what happens is most of the dark matter particles will go right through the earth without even knowing is there But every now and then if we're right one of them may bounce off a nucleus of germanium And it'll heat the whole thing up roughly by one one thousandth of a degree And so you put the whole thing underground and you try and shield it from radioactivity And you hope maybe once a year once a decade once a century you'll see a blip That can't be explained by anything else and that might tell us the nature of the dark matter What's as I said after Tara's talk the interesting thing is? There's a race between the large Hadron collider and experiments like this to see if the dark matter is made of this stuff One or both should see it and that's incredibly exciting But it turns out it doesn't matter what it is again It's I think Frank mentioned afterwards it doesn't matter because we just want to know how much of it there is because it's its Gravity that will determine we thought the future of the universe So let's go back to this and say how much stuff is there when we weigh the universe like this? And we've come up with the answer after 80 years. We've come up with the answer and I'm going to show it to you a drumroll Okay, whatever and There it is Okay, I can there people back of the room. They're fainting right now Now ways when physicists have an important number. We always give it a Greek letter to sound scholarly and Omega which with George alluded to is a very important quantity Omega We call the it's a quantity that defines for us the ratio between the actual amount of matter in the universe and The amount of matter to make an exactly flat universe So if Omega is less than one the universe is open and if Omega is greater than one the universe is closed And you can see here even from a long time ago that At high accuracy and the numbers have gotten better The there's only 30% of the amount of stuff to make a flat universe So it looked like we got the holy grail We'd finally figured out the universe is open end of story. No need to have talks and such etc But there's a problem The problem is we theorists knew the answer because we always know the answer We're not often right, but we always know the answer Okay, and we knew that the universe was flat Because a flat universe is the only mathematically beautiful universe and here these darn observers were doing what observers do so well Which is get it wrong? we thought but there's clearly a loophole here which is This determines how much stuff is around galaxies and clusters of galaxies But what about all the stuff where there aren't all the regions where there aren't galaxies clearly? There's huge ways of missing stuff And this is a very weird way of determining the geometry of the universe because this really tells us the geometry of the universe We thought because you have to plug the matter into Einstein's equations and solve Einstein's equations Measure other quantities like the expansion rate of the universe plug it all in and from that try and infer the geometry of The universe wouldn't it be better to measure the geometry of the universe directly? And what's amazing is that we can and we have been able to and I'm thankful to George in some sense that he's He didn't talk too much about it. So I can We've been able in the last decade or so to measure the geometry of the universe, which is just remarkable in the extreme Now, how would you measure the geometry of the universe? Especially if you let's ask how you could measure the earth is curved if you couldn't go around it or you couldn't go into a Satellite, okay, you just live in Kansas. How would you know the earth is curved? Well, very simple and draw a triangle and You ask Gustavus Adolphus student one of the some of the angles in a triangle you ask Anyone else and they won't know but it's 180 degrees, but I'm assuming that they have a good education here I can tell and That's fine because we all learn our geometry from Euclid As Frank pointed out But in fact on a curved surface It's quite different and in fact he showed a slide about that but on a curved surface like the surface of the earth I can draw a triangle as follows I can go along the equator then I can make a right angle and go up to the north pole and then another right angle and Go back to equator and I got I got a triangle with three right angles Three times 90 is 270 and 270 isn't 180 So if I made a draw a triangle was big enough on the surface of the earth, I could prove the earth is curved and what is truly amazing is that same Thinking works not just in two dimensions, but in three dimensions if you could find a big enough triangle in our universe You could measure the curvature of the universe and that's what that's what we've been able to do People were trying for a long time and we've been able to do it with the causing microwave background radiation that George So beautifully talked about I Remind you from George's talk that when we look out at the causing microwave background radiation We're looking back at a time when the universe was a few hundred thousand years old back to the moment when it became transparent now Seeing the the images of that baby universe, and I'll show a different version of it is amazing It's worth a Nobel Prize or two in fact at least two But what's equally interesting is is there's a very important scale on that surface, and that's one degree Because one degree Represents in general in certain cases and in a case that I'll talk about a hundred thousand light years across on that surface Approximately, and if the universe is about a hundred thousand years old Einstein told us that no information can travel faster than the speed of light And if that's true nothing on this surface over here Could ever could affect anything at that surface over there because that's how far light can travel in the history of the universe Okay, and certainly at that time that that surface was created now that sets an important scale Because if I have a lump of matter That's smaller than that scale. What does that lump of matter do as George pointed out it collapses And then it heats up and it does all the sort of things that lumps of matter do But if I had a lump of matter that's bigger than that scale it doesn't even know it's a lump It's like I used to watch a lot of TVs It's like while it widely chaotic on the Road Runner if you remember he used to run off a cliff and then he'd hang around a while before he realized He's supposed to fall and that's exactly what would be the case lumps bigger than this Don't know they're supposed to collapse So the biggest lumps that can have collapsed or begun to collapse the moment they might go in background University becomes neutral when things can begin to collapse as George pointed out The largest lumps that can collapse are that big but that creates a ruler for us It creates a ruler. That's a hundred thousand light years across. Well, let me just go back for a second So that's a ruler and it creates a triangle We can ask how how big are the largest lumps and to go back to this image as and this is again I think something a Frank's slide showed you know in a flat universe and by the way a flat three-dimensional universe is not a Pancake, it's just the universe. You always thought you lived in where the x y and z axes point in the same directions everywhere in space okay In a flat universe light travels in straight lines and a hundred thousand light year across Ruler or lump should span on our eye one degree But in an open universe where light rays diverge as you go back in time The angle spanned by a hundred thousand light year across ruler will be smaller the ruler the lump will look maybe half a degree across And in a closed universe where light rays converges you go back in time The ruler will look bigger so all we have to do is take a picture of the types George took and Ask how big are those biggest lumps and that's what we've been able to do and and the first Experiment that began to really address this was not a satellite experiment. It's a ground-based experiment It was in Antarctica the boomerang experiment was called it was it here's a a balloon and a microwave Radiometer and it was sent up above the earth to be able to look carefully At a small region of sky and that balloon went around the world Which is of course easy to do in Antarctica if you're the South Pole you just do this But but it wasn't there was it McMurdo So it when it took about two weeks to get around and come back to where it began what was called boomerang and Then it took this image which superimposed on the original image Here are the hot spots and cold spots of the stuff the type that George showed As observed first by Colby and then much harder detailed by other satellites But here they are and the question is these are the primordial lumps See point out that were created at the very beginning of time that would later collapse that form everything we see the galaxies the stars the planets Etc. But the important question is how big are they on average? so to see that way we can create universes in the laboratory and and on a computer Well, I guess I wanted to show the plank picture just to show we do much better now, but I figured George will show it and And here's boomerang here's that same region of the sky looked at and in a different false color image And here are universes on the computer We create a closed universe an open universe a flight universe and we ask how big on average with those lumps look and In a closed universe the average hundred thousand light-year-across lump would look that big, but that's bigger than these lumps In an open universe the average hundred thousand light-year-across lump would look that big, but that's smaller than these lumps But just like Goldilocks In a flat universe. It's just right and in fact we now know to an accuracy of perhaps better than 1% That the observable universe is flat So if you're a theorist you can do this Okay, well you shouldn't pat yourself in the back too much because of course There's a problem here, which I hope you're aware of isn't a few minutes ago. I proved the universe was open We've only measured 30% of the amount of stuff To make a flat universe and so there's a big problem. Well if the stuff isn't where the where the galaxies are It must be where galaxies aren't But what is where galaxies aren't? nothing now The amazing thing is that we have learned one of the great developments of 20th century physics is that nothing is not so simple When you put together the laws of quantum mechanics and relativity Then empty space becomes a dynamical thing much more dynamical and when you put together quantum mechanics and special relativity It turns out that there must be that the empty space is really a boiling bubbling brew of virtual particles That are popping in and out of existence in a time scale so short you can't see them Particles we call virtual particles now that doesn't sound very impressive. It sounds like counting angels on the head of a pin Okay, but so you know the purpose of science isn't to invent things you can't see that's the purpose of other things I won't go into as a moment, but So if they if you can't see them then how do we know they're there we can't see them directly But we can see their effects indirectly in fact They're required an essential part of understanding of modern physics this image which all of you have been staring at While I've been talking I see what's actually something that Frank showed at the Nobel Prize ceremony It's actually a while it's an while it's an animation. It's it's more than just that it's based on real calculations This is what the empty space inside of a proton looks like Now if you went to a good high school, and I'm sure the students here did You learned that protons are made of three quarks, right? Okay, well we lied Okay, they're not they are made of three quarts But it turns out if you add up the mass of those quarks they account for almost very small percentage of the total mass of the proton Most of the mass of the proton comes from the fact of these virtual particles popping in and out of existence these fields Giving energy and mass to the proton so maybe 90% of the mass the proton or more is due to these virtual particles and fields So you wouldn't be here if those parts of virtual particles didn't exist. That's how important they are so If and in fact Frank won the Nobel Prize for the theory that allowed this calculation to be performed So if we can we have a theoretical basis for calculating the contribution of Virtual particles to the inside of the proton Why not apply the same ideas to empty space and ask how much energy would these kind of virtual particles give to empty space? And that's where you come up with the result that Alex mentioned. I noticed kindly the one is missing from here, but If we do the same kind of calculation We get we estimate that the energy of empty space is roughly a gazillion times the energy of everything we see It's indeed is the worst prediction in all of physics. Although maybe some of my colleagues here have made worse. I don't know but but What we know is that the energy of empty space cannot be much more than the energy of matter or we wouldn't be here and So this this problem has been around since I before I was a graduate student But certainly when I was a graduate student and since then which became called the cosmological constant problem Why should the energy of empty space not be up a good 120 orders of magnitude larger than everything we see? And as I alluded to in the panel earlier We were able to go to sleep at night because we knew the answer because we're theorists and We knew the answer had to be exactly zero because zero is a beautiful number More or more than that There's a real other more relevant physics reason if the energy of empty space was not going to be bigger than the energy of everything We see we have to cancel this big number to 120 decimal places leaving a non-zero number in the hundred and twenty first decimal place No one knows how to do that But zero is a number we know how to get in physics We have mathematical symmetries of the type Frank talked about and others that that it's their mathematical symmetries that might cancel Things exactly so we all knew we all went to bed at night knowing that there was some symmetry of nature That would cancel things exactly and the answer was zero and and so we didn't have to worry about it But physics is an empirical science and as I will argue in a bit the universe doesn't give a damn What makes us happy and so what we really want to know is that really the case and the only way to do it is to observe it Now it turns out if you put energy in empty space as has been alluded to in general relativity it is remarkably Gravitation or pulse of all the people who've taken physics here know that gravity sucks Okay, but in fact for empty space gravity blows okay, and That is remarkable and that means if you look at the expansion of the universe Over time instead of slow if the universe is dominated by the energy of empty space The expansion of the universe will speed up not slow down now as Alex talked about in 1998 Several groups of astronomers were trying to measure not that the universe was speeding up But they were trying to measure the rate at which the universe was slowing down Because that's what a sensible universe should do and to do that They had to measure very carefully the rate expansion rate of the universe And I just want to show to give Understand how much better the things are with type 1a supernova of the type that Alex talked about here's Hubble's original data On the expanding universe from 1929 velocity versus distance This is one of the reasons he was such a great scientist because he knew to draw a straight line through that data set and not so obvious and He also did something else that astronomers have you depend upon ever since then he got the answer wrong by a factor of 10 They've tried to emulate that I mean he didn't do it because he was a bad astronomer He did it for precisely the reasons that Alex talked about to measure velocity and distance You have to measure to know the distance of objects You have to know you have to have a standard candle and it's very difficult to get standard candles in the type 1a supernova I that he talked about have changed everything Here's that picture he showed this is a I love this picture. It's a of an exploding star as bright as a galaxy It's about 90 million light years away and one of the other things I want to do just to add to what he said to maybe maybe Emphasize this point is that we can we can use these things and and here's a here's a nice Movie made by one of the two groups that he worked for this is a exploding star You can see its brightness over time and then and its colors and I'll re it'll keep reproducing over time while I talk about it the amazing thing is That you can do this and he alluded to wise using statistics But I want to just emphasize it from a slightly different perspective if you went out tonight And it's a clear night and you held up a hole in your hand about the size of a dime Okay, where you couldn't see any stars With the largest telescopes in the world of the type you showed you could see a hundred thousand galaxies in a region that big and And if you do the calculation once per hundred years per galaxy if you can see a hundred thousand galaxies in a single image like that You're bound to see a star explode and people like him apply for telescope time to do just that and they do it And it's amazing. It's an important lesson the universe is big and old and rare things happen all the time another lesson that I think has Implications in different contexts as we'll talk about things sometimes just happen even if they're very strange Okay This is to show you how much better you can do now. This is a modern Hubble plot with the type 1a supernova this was of course developed after the Profound mathematical discovery that on a log log plot everything's a straight line But still aside from that guide to the eye We can now use that to measure the Hubble constant to an accuracy of better than maybe five percent Not a factor of ten as as when Hubble got it wrong And that allowed these groups as he pointed out to produce result And this is actually there was the cover of science was shown But then afterwards this is the the two groups data. This is the Hubble plot This is the distance versus velocity and the question is what happens to it at very far distances Does it turn up or turn down and the way to see what what happens is to draw a straight line through that data set and make the Whole thing horizontal so a straight line would be a horizontal line here and what they and and the and the both groups were looking for was to see how these distance supernova I would follow this curve going down because that's what a sensible universe should do and What they discovered to their amazement is that the supernova? I didn't even lie below the straight line or on the straight line. They live above the straight line and There's two explanations of this one the data is wrong, which it usually is but in this case it isn't and two Empty space has energy and the universe is accelerating Now if just for fun you try and fit the data and ask how much energy would you have to add to empty space? Fitting the data you get exactly what we were missing if you put 70% of the energy of a flat universe in empty space Everything works That's another reason why scientists are so quick to accept this result Not just because it was a convincing result that the universe is expanding There were lots of things that might have suggested that was wrong, but the universe is flat only 30% in matter and this fits exactly So that is the cockamamie universe we live in that of those that is a profound result We live in a universe a flat universe and with 70% of the universe is dark energy this stuff that we that the energy of empty space Almost 30% of it is dark matter and a little bit of cosmic pollution Actually 1% of it is what we can see it's true that it was mentioned to be 4% But most of that isn't even visible if you look at the universe that we can see if you take all the stars and galaxies and everything You can see on a beautiful night here in Minnesota and get rid of it and us and everything the universe would be largely the same So so much for a universe made for us We are a little bit of cosmic pollution in a universe of dark matter and dark energy and it's changed everything And I want to spend the rest of talk talking about the implications. So let me summarize The dominant energy in the universe resides in empty space We don't have the slightest idea why it's there and I want to remind you We do not have the slightest idea why it's there and in deference to my good friend Jim Gates If anyone comes here and tells you they understand it, they're lying especially if they're a string theorist and Its existence is tied we think to the very nature of space and time into the origin of our universe Which is why it's so interesting to us and as Alex alluded to but I'll describe in a little more detail it will determine the future of the universe In fact, the reason I got into cosmology was the wrong reason because it turns out geometry is irrelevant Doesn't matter what we live in an open closed or flat universe The future of the universe is determined not by geometry, but by the energy of empty space okay Now I want to I was gonna ask for your apple I meant to ask Alex for but pretend I have Alex's apple here No, it's okay. I'll just love this is good enough for me. It's more likely. I'll catch it So if I throw we I want to take you back to one of your favorite times in in high school, which is high school physics, okay? We teach high school students how to Calculate what will happen I throw a ball up in the air if I throw it up as you pointed out It'll come back down if I throw it up faster come back down a little bit later And if there's no ceiling if I throw it really fast it won't come down at all and here's how we do the calculation We turn it into bookkeeping We say that that the energy of a apple has two pieces that we call it the kinetic energy in the potential It doesn't matter. There's a positive piece, which is the energy of motion There's a negative piece which is due to the gravitational pull of the earth and it just becomes bookkeeping if the total energy The total some of the two energies is positive the coin will escape if It's negative it'll come back to earth and that's what NASA uses every time they try and figure out whether how fast to throw a satellite up into space But we could the remarkable thing is we can use that to to discuss the universe as a whole Because if it's expanding and it's the same everywhere Then what happens to every galaxy in the universe will happen to any galaxy and Therefore if we take a region where we're at the center and ask what's gonna happen to the universe We just have to look at one galaxy that's moving away from us And if it stops and comes back then they all will and then the calculation becomes just like an apple We want to know the two pieces of the energy of this thing the positive piece depends on its speed away from us But that's what mr. Hubbell and others have told us That's the positive piece the negative piece comes from the gravitational pull of all the stuff inside We're including the dark matter that we've discovered So all you have to do is compare those two things and you can determine in a matter-dominated universe the future Okay, now the interesting thing is if B if the negative piece beats the positive piece if B over A is bigger than one Then that then that region will collapse again if B over A is less than one the universe will expand forever But what is truly remarkable is we now know in a cosmic sense that B over A is nothing other than that quantity Omega Which we've measured we live in a flat universe Omega is one and if Omega is one then B over A is one And if B over A is one then B is equal to a but if B is equal to a the negative piece equals the positive piece And that means the total gravitational energy of every object in the universe is zero Now if you were gonna make a universe from nothing, what would you make the total energy? The first idea that maybe maybe You can have a free lunch and in fact as Alan Guth has said the universe is the ultimate free lunch So now let's go to this question. How wise or something rather than nothing? The first answer that what we have to be a little careful and describe what we mean by nothing So the first kind of nothing is say the nothing of the Bible of an infinite void a dark infinite empty void empty space Well that kind of nothing. It's easy to get something from in fact. It's impossible not to Because that kind of nothing is unstable This is what nothing looks like we've seen it its virtual particles popping in and out of existence. Well, that's not real stuff How can you get a hundred billion galaxies? Well, when you add gravity to the mix The reason these particles pop in and out of existence and it's such a short time It's because something called the Heisenberg uncertainty principle when you take particles and you pop them into existence They have energy but if they stayed there they'd violate energy conservation because there wasn't anything there to begin with So they have to disappear Before you can see them quantum mechanics is kind of like the White House in corporate America if you can't see it anything goes and But when you have gravity into the mix Then these particles can have gravitational attraction which produces a negative energy and the total energy of the particle Antiparticle pair of pops into existence could be zero and if that's the case those particles can exist with impunity There's no violations And so you're guaranteed if you wait long enough in a universe that survives long enough empty space will start spewing out particles and You can get a hundred billion galaxies worth of them if you had to There's nothing that violates Any of the lone laws of physics to get something from nothing. You don't need supernatural shenanigans Okay, well that mom some people say Somebody would say That that's not nothing Because after all where did the space come from you got the particles, but where did the universe come from? Well, the interesting thing is and we don't have a theory of quantum gravity I want to emphasize that we do not have a theory of quantum gravity Okay, we're working on it many people are and many people think they have hints of it But one of the things we know about any theory of quantum gravity is it's quantum mechanical And quantum mechanics tells us that in space Particles can pop in out of existence quantum fluctuations can happen Gravity is a theory of space and time If we quantize that that space and time become quantum variables and space and time could pop in and out of nothing And I think Frank showed a picture with some people would in different versions could say is just that When you add when you in any theory of quantum gravity when you put quantity and quantity of quantum mechanics together It allows spaces and times to pop into existence It means that there's no space no time and poof our universe pops into existence Now most universes that pop into existence will pop out of existence just like virtual particles Okay, you know microscopic time What kind of universe could exist with impunity a Universe with zero total energy now it all begins to sound like it's all coming together But it's not so simple and I don't want to pretend it is Because it turns out the only universe that we can actually mathematically prove has zero total energy is not a flat universe It's a closed universe So what gives? Well, most closed universes as you saw will expand and collapse and they'll expand and collapse if they created Microscopically in a microscopy short time the only closed universe That could not that would survive long enough for us to ask the question is One in which there was a very early period of accelerated expansion that would puff it up so large That it wouldn't collapse right away But that's precisely what particle theory now predicts this theory we've heard mentioned several times called inflation predicts naturally based on the extrapolating the kind of physics we talked about that Very early on the universe there was a period of accelerated expansion when it when it increased inside by a volume of at least 10 to the 90th in a timeframe of a millionth of a billionth of a billionth of a billionth of a second It sounds like science fiction, but it's not Now what will that do? Well, what would inflation do if it happened in the early universe it would take a closed universe and puff it up But if it pops up what would happen? What's like puffing up a Balloon and making it the size of the earth when you puff up a universe that's curved you make it look flatter and Therefore the only closed universe that could survive long enough to live to be enough for us to evolve Still can use that word here is one that had an inflationary period and therefore one that must look flat So then fact the only universe that can be created from nothing by this kind of mechanism and survive long enough for us to Be around is a universe that looks flat Precisely like the universe we live in and that's the point I want to mention We can't show because we don't have a theory yet that the universe came from nothing by this But it's plausible and that plausibility is amazingly worth celebrating But more than that we can ask the question What would a universe look like if it was created from nothing by just laws of physics without any supernatural shenanigans? And it would look exactly like the universe we live in and that is remarkable But that's not enough Because some people say that's not nothing Because you you don't have particles you know of radiation you don't have space you don't have time But what about the laws? What about the laws themselves? Well, it turns out that even the laws of physics themselves may be accidental and To do that I want to answer that the question Sam asked actually in the panel a little more rigorously and And and Alex alluded to it's this amazing coincidence. This is a brief history of time That's the last as George to say it's the last complicated picture. I'm gonna show you so it's downhill This is the density of matter in the universe as the universe expands the density goes down This is the density of empty space energy density of empty space it remains constant And we live in a time 13.8 billion years after the Big Bang when the energy of empty space is roughly three times the energy of matter That's the present time, but when you look at this or when physicists look at this they go crazy If you stare at it long enough Because Copernicus told us it's not supposed to be this way Why should we live this we live in the only time period in the history of the universe when these two numbers are about the same When the energy of empty space is almost the same as the energy of matter. Why should that be the case? It's not supposed to be the case. There's nothing special about 13 8.8 billion years There's nothing special in the fundamental constants. We should just live in an average time. Why are we living in such a special time? Well physicists have thought a lot about this and one of the answers is Here grab galaxies exist as was pointed out and I want to explain that Let's say the energy of empty space were 50 times greater So that line instead of being here was up here Well, then these two curves would cross at a different point They cross in this case at the point when galaxies first formed But if the energy of empty space was greater than the energy density of matter Before galaxies formed galaxies wouldn't form because the repulsive force would beat out the attractive force So if the energy of empty space were much bigger than it is today Galaxies wouldn't form and that's led physicists to something I like to call Anthropic mania The argument is perhaps there are many different universes and the energy of empty space is just a random variable It changes in each universe Then only in the universe in which we only in the universe in which it's not much greater than we measure today Well galaxies form and only then will stars and planets form and only then will astronomers form So the universe is the way it is because there are astronomers here to measure It sounds funny it founds almost religious it sounds like purpose, but it's not that's a mistake It's the same mistake you make if you assume the fact that bees can see the colors of flowers is because they're designed to do so That's due to evolution a natural selection. This is a kind of cosmic natural selection We would be amazed to find ourselves living in a universe in which we couldn't live that would be worth writing a book about So it may just be a remarkable accident to associate with our existence that the reason we find this value Is that if we're different than we wouldn't be around in our universe? It's awful of course because it turns physics into environmental science God forbid, but nevertheless it may be true But particle physicists have jumped on this because particle physics is way ahead of cosmology There are many more problems. We haven't understood for much longer than cosmology We don't understand why gravity is the weakest force in nature We don't understand why the proton is two thousand times heavier in the electron We don't understand why the three generation of elementary particles Those are the kind of things that our inner colleagues are trying to address with experiments and and theorists are also trying to address So some physicists have jumped on this at this is great. We don't have to understand anything Maybe it's all an accident Maybe it's just if it even were different we wouldn't be here and then we don't need a theory of everything We just need a theory of anything But we have such a theory. It's called string theory so So I want to get before George, you know Jim may give a longer version, but I'm gonna have a short version of string theory So this one guy says to another I just had an awesome idea Suppose all matter and energy is made of tiny vibrating strings the second guy goes, okay What would that imply the first guy says? I don't know so that's a history of string theory over the last 40 years or so and And it's had its good times and bad times But one of the things that nevertheless and it's a well motivated theory. I don't want to make any more fun of it but One of the problems and opportunities I suppose a string theory said it in general requires many more dimensions than the ones we actually see and measure 10 or 11 in most of them and The question is always where are those dimensions? We don't see them and one way to get rid of them is to curl them up into very small volumes But what's amazing is every different way you curl up those extra dimensions in string theory You end up with a residual universe with different laws of physics And so some people realize there may be 10 to the 500 different possibilities Even if there's only one string theory, there may be 10 to the 500 different four-dimensional Universes that could result to each of which would have different laws of physics depending on how you compactify these extra dimensions, but Then you see then you're guaranteed to find a universe like ours because in each universe It could be different laws of physics and the different energy of empty space one of them is bound to look like ours Now is that science? I mean if you could if you have something it's consistent with any possibility that could ever arise It's interesting philosophical question whether you have a scientific theory and that's something to be discussed, but whether it's Not is or not it may be true Whether I like it or not and I don't Well, I've learned is it again the universe doesn't give a damn what I like and So this may be true But if this is true when a universe pops into existence the laws of physics pop into existence along with it and so you got No space no time no particles no radiation no laws to me. That's a pretty good approximation of nothing Now I want to end with another version of nothing It was one that came to me for my late very good friend Christopher Hitchens because I used to talk to him about science a lot And when I told him about this he said you know what nothing is heading towards us as fast as can be And I want to loo to the future Alex talked about it a little bit, but The first person to realize the future was really miserable was was of course, George Orwell Who said what to see what is in front of our eyes or one's nose requires a constant struggle, okay? And this is clearly what he meant by it What he meant is that if you put energy in empty space constant energy universe is going to expand That's going to expand faster and faster and faster and something that really hasn't been alluded to is Eventually objects will be moving away faster than the speed of light That's allowed in general relativity We teach you that nothing can move faster than light, but we lie We have to be like a lawyer and parse a little more carefully Nothing can travel through space faster than light, but space can do whatever the hell it wants And if empty space has energy there are regions now Which are well in fact there are regions now moving away from us faster than light and we can calculate that In fact, we can calculate the distance for away from us beyond which objects are now moving away faster than light It's 18 billion light years and we're universe is 14 billion years old or so So these effects are just becoming beginning to be visible and they're gonna get worse Because when objects are moving faster than light we can't see them the light can't make it back to us They literally disappear in ways that I don't have time to discuss But I've tried to use this indeed Alex before Congress to say that we should measure things now while we have a chance But this did the time frame of this happening is like What I'm gonna talk about happening is two trillion years and that's a lot longer than the long-term future for a congressperson Which is two years so it doesn't work Yeah, never gets to us Okay, but this means and it's been alluded to but in a much more dramatic way than I think it's been alluded to the rest of The universe really disappears and This means in the far future as was pointed out. I find it quite poetic I said That a huge single human life time ago. We thought the universe was static and eternal what I didn't say Was that Hubble also was one of the people discovered there was more than one galaxy In 1925 the picture of the universe was that was static eternal and the Atari universe consisted of a single galaxy our Milky Way Galaxy in 88 years a single human lifetime. We've discovered 100 billion of them That's why we're like the early map makers just beginning to understand the universe on largest scales It's not surprising that we're surprised all the time But in the far future, it's very poetic Astronomy they'll still be stars around in two trillion years There's to be main sequence stars and astronomers on those main sequence stars Will evolve because they'll be carbon and they'll be and they'll evolve and they'll discover the laws of physics of quantum mechanics of Relativity they'll build telescopes and they'll look out and what will they see? Nothing outside their galaxy the universe that they believe they'll live in will be the universe We thought we lived in a hundred years ago with a single galaxy and all evidence of the Big Bang will have disappeared But after that happens these stars will burn out and the universe will become cold and dark and empty So I'll accept so in that case as as Christopher put it the simple answer the question Why is there something rather than nothing is just wait there won't be for long? And I think that's the most important answer because it demonstrates our incredible cosmic arrogance Many people think we're the pinnacle of evolution, but it's not that if evolution had some purpose to get to us and it stopped Okay, and many people think the universe that we live in is the universe is the way it was always was and always will be it's not It's going to be quite different, and we won't be around and there'll be nothing around in the far future So to conclude Science has demonstrated that a universe from nothing is not only plausible. I would argue but likely and What I what's really important is that what we mean by something and nothing is completely changed from the time the classical Philosophers and theologians first raid the issue Thousands of years ago that upsets some people when I say that That science has changed the meaning of things that came out of it, but it's actually called learning Okay, we should celebrate it and Really the important thing is that I want to point out is why is there something rather than nothing is not the important question? In fact, it's not even a reasonable question Because why is there something rather than nothing assumes purpose? Whenever you ask a why question it assumes purpose in fact why questions are fundamentally meaning us whenever we ask why we really mean How and anyone here whose a parent knows this When your kids ask why why why why the only answer inevitably is because go to bed Okay, what really is the important question is? How? How did the universe evolve and how can we find out and that's what we're celebrating here today? And the amazing discoveries we've ever talked about are continuing and the surprises that are going to happen Well that what we now know will compel in comparison to what the young people here will discover as some of them I hope become scientists So to really conclude I've told you two things first You are much more insignificant than you ever imagined and second the future is miserable Okay, but you should be happy because You know we may live in a universe without purpose But what does that do that means the purpose in our lives of the purpose we create and we should consider ourselves Fortunate to have evolved in this place in the middle of nowhere and evolve the consciousness where we can understand the universe The earliest moments of the Big Bang to the far future sitting here in this remote place in the middle of nowhere And so instead of being depressed you should enjoy your brief moment in the Sun. Thank you very much Thank you for pressure Krause. That was the best talk. I've heard about nothing ever At this time I'd like to bring the panelists up for the question-answer period and in a couple minutes We'll get started with the Q&A session Please pass your questions to the ushers as they come around I really enjoyed your talk Go ahead and get your power supply Okay, folks, we're gonna get started in just about a minute here So if you could find a seat pass your questions to the ushers and bring we'll bring them up front for us. Thanks Okay, we'll begin the Q&A session now with questions from the panel and we'll start with Professor Philip Filipenko So Thank You Lawrence for that very interesting talk. I wanted to clarify one issue though one can there are many issues but One can imagine a universe spontaneously forming out of nothing as a result of quantum fluctuations Essentially and then inflation making it grow and it has essentially zero energy But does it presuppose an existing set of laws of physics? Well, that's you know, it's a good question We were talking about before this began but What I wanted to point out it pre obviously well the answer is yes and no Because because the answer is yes, it could be that all possible laws occur It could be that all possible combinations of laws It's but I mean multiverse doesn't have to be finite It could be it could be that every possibility that can happen happens And therefore every possible set of laws of physics may exist and that's the same It seems to me is having no laws and basically it's saying that there's no selection effect It's just anything it can happen happens But it could be and in fact in the case of string theory There is some underlying law and in fact You didn't say it explicitly, but I'll say it. I assume quantum mechanics there I mean in order to have quantum fluctuations when I student quantum mechanics I don't know how to I can only work with what I have as a physicist There could as far as I know it's possible that quantum mechanics itself may not be Universal, you know, I we don't have a fundamental law of physics. So I Don't the answer is of course one doesn't know and and not knowing is a wonderful thing And and so there may be a unique set of underlying laws, you know an 11-dimensional universe There may be every possible set of laws the universe In this multiverse that can happen And my point is therefore that it's not so it's not as if you need If we ask what people really mean when they ask what's the miracle of existence? Most of time they say how can you get the stuff we have unless someone said let there be whatever and the point is It's not a miracle to have stuff where there was no stuff. That's no miracle It's not a miracle to have a universe where there was no universe. That's not a miracle And you don't have to have a uniquely set of prescribed laws of physics for us our lives or our universe to rise Indeed, there may be some underlying law of physics in the universe and I don't know the answer but that doesn't to me the important question is how did our universe get here and You know, maybe I push this question. Why is there something rather than nothing back to the multiverse? I don't give a damn. It's not the thing that interests me. The interesting thing that interests me is how did our universe get here? But it's an important but even the multiverse its existence is Difficult to comprehend unless there's some underlying set of laws that allows it to but difficult to comprehend is different than Existence that's what's wonderful about physics is that things that were difficult to comprehend Happens and we've been able to comprehend them There may be ultimately things we'll never comprehend. I don't expect I'm one of the people I don't think we'll ever have a theory of everything I would be amazed if we did and I think that's the wonder and beauty of science the mystery is what makes life worth living and so Absolutely, I can't comprehend the word the words you're using I can't I can't comprehend mathematically or because I don't if I could I'd write it down in a physics paper and So you're absolutely right. These are issues We don't understand but they don't take away from the remarkable fact that It used to be that life was a miracle and had to demonstrate something beyond the laws of nature that they happily Darwin got rid of that and I would argue that physics is getting closer to the point of saying at least to understand How our universe got into existence. We don't have to pause it anything supernatural Lawrence well, okay, Lawrence first of all stellar performance. I'm sure the audience appreciated it and I and for these Thank you and Since you're such a great supporter of the string theory community. I want to thank you for your And I like to give you a free advertising But my serious question is a following you might be surprised to at least in my own personal views Of physics that I find a lot of resonance with what you say in particular the whole question about what are the laws of physics? Themselves actually had some sort of natural selection to act upon them Would you be surprised if I told you that I in fact accept that and have some minor evidence that that is true Well, I I wouldn't be surprised. Well, I first of all, I don't think you should accept anything That's really a key point. So you shouldn't believe anything. Well when I said except I mean provide my own internal yeah, okay I mean if you could see evidence then that's a good bit I There's lots of indirect evidence and I happen to think the phenomenon of inflation is the best motivated evidence There might be a multiverse. It's my opinion, but no, I wouldn't be surprised that if you agreed because I've known you for a long time and your sensible guy That sounds like a cop out to me So when you're saying evidence, do you mean a prediction that we can test experimentally and I know I do not you want to give it I know everyone's wondering so why don't you give it? Well, actually some of the people in this auditorium have actually heard a talk there You know large I've been mucking around down in the mathematics of supersymmetry and We have found these weird and some people say Unimportant but evidence of what looks like error correcting codes There's only one place in nature In the observed world that I know where error correcting codes occur and that's in natural selection And it's even not completely clear there, but there are yes, you know geneticists who make that argument. I mean it's fascinating I'm skeptical, but it's but it's you know, it's great I think and it's amazing it'll be amazing I think what's amazing and what I try to try to illustrate is that we can even ask these questions I we couldn't we could have had a symposium 30 years ago a Nobel symposium and we could have asked the questions But we would have had any sensible and I mean, I'm not sure you'll argue that my answer is sensible But but we know so much more that we've gotten to the point where these questions are even discussed among scientists Which I find fascinating I think a lot of the issue that Alex was raising Many people raise in connection in this connection is what exactly do you mean by nothing? Well, I thought I thought I made it clear No Not entirely clear I've as you know Almost exactly 30 years ago. In fact, I made a proposal very much along the lines that you discussed here in Scientific American With a rather precise however formulation of what nothing means I What I took as nothing is the idea that the universe would begin in a very very symmetrical state with no matter and Much more symmetry the symmetries that are broken in our world would be Restored we know many of them are restored so we could assume that there was a much more symmetrical state early on With for instance equal amounts of matter and antimatter And then I think it was already plausible then and it's become as you mentioned much more plausible now That the laws we know operating on such a state could lead to something very much like our universe But I wouldn't overstate how that means you're getting a universe from nothing. You're getting a universe from a framework of An assumption about what the initial state is and what the laws are and I well And if both of those are certainly still Up for grabs to a large extent especially The assumption about what the initial state is or even whether we should assume an initial state for instance one can Sensibly speculate about whether that's the right formulation at all Maybe the right formulation that would be more symmetrical would be to say something about the final state Yeah, no it that mean cosmology as you know with there is a subject that's changed a lot You emphasize that in fact And I don't think it's over yet. Well, I think very fundamental level Well, I think obviously I resonate with a lot of what you said And I agree that one should be careful as you should have been careful when you wrote the scientific American article and put Said why is why is there something rather than nothing because nothing is unstable does it work? That's exactly what I said you know and so we all use these terms and what we mean I think You look when can have a huge philosophical discussion by the nation nothing I think it's largely a waste of time myself But what what what we operationally mean is that you might say nothing is non-existence And the question is how could you get something that exists now from something it didn't exist before That's the weird thing now whether there was absolutely nothing else is Interesting question, but it's not the question. I think that one's addressing ones. How can you get something that exists? When it didn't exist and actually that's no surprise people seem to find it surprise You know look at the light from the photons are coming from that light while they were emitted spontaneously by electrons that jump between Levels and atoms did the photons exist before the electrons emitted them? Absolutely not So there are photons that came into existence. It doesn't bother anybody somehow it bothers people when we talk about a universe So you're absolutely right one has to be careful, but I tried no space is one version nothing But no I mean no particles as you pointed out is one version nothing But no space is a much more interesting version of nothing no space and no time and Pointing out that even a you even a space can come into existence when it wasn't is a fascinating thing to talk about it Maybe maybe I think you're overstating how much that can be done You need something out you need a space out of which another you can have more space and rising out of some space No, I think but I think you're you know no hold on a second It's very agree that you may that a space time which didn't exist a four-dimensional closed universe Could come into existence that didn't come it wasn't into existence before you will agree It doesn't start from nothing I did it starts from a special initial but it wasn't doesn't start from a universe that existed before because that universe Wasn't there. Well, that's my point being by a universe. Well, the rest is cementing nothing. I know it doesn't it's Well, I mean I I think it's a remarkable thing that a that a universe can have zero Well, you're not the only one it can interrupt Frank But it's a remarkable thing that a universe can have zero total energy and come into existence No without with no question That's all I wanted to point out when Einstein first learned about that He almost got himself run over by by stopping in the middle of the street in Princeton. Yeah And so I think ultimately we're in a striking observation. There's no question. Yeah, but I think the thing that confuses and upsets some people and well, I in fact, I know it does and At least not me it doesn't bother me. I don't care. Oh, okay Except except because of my sympathy for other people But when you say nothing You said that's a mean that's your thread in your title. It's It's it it means Something to it means different things to different people. That's why I tried to find I think I was real I would try to be careful about what I meant by nothing. So did I well I define three different versions of it. I think once you start talking about the laws being random or no laws at all You could really start from nothing at all. I think that's going too far I think it's really within a specific framework that you can discuss these well I and you definitely invoked quantum mechanics. You invoke relativity You know, absolutely. I gave an example by which the universe would come into existence But I made a key point that we don't know Lawrence. What do you mean by exists? Well, that's a good question It means having a panel discussion Well, it's a you know, that's those well as a as a physicist what existence means to me is that I can measure it Or not that I can measure that Tara can measure and that's fine That's fine, but that is not exhaust the meaning of exists. You're right, but it's all that I care about Okay, okay, it's fine. Okay. I mean seriously. It's a little maybe my own limitation But if I can't measure it then as a scientist and that as a scientist I'd if I can't measure it even in principle. Obviously we talk about we've all created the theorists on the panel things We can't measure but in principle we could imagine them being measured and as a scientist if it's not related to that It's just not science, right? So I would like to sort of tie that with what what Frank was just saying and that is 30 years ago you had couldn't have this discussion and 30 more years you're gonna have a really different discussion I mean the fact is we are putting in a lot of cultural Scientific cultural prejudice into our models and it is true You can make up a model in which you get the universe. We're living today From a place that had no space and time and no particles and energy or something that that's perfectly a reasonable Prescription you can kind of I've actually assigned it as a homework problem and have my students choose the coefficient of the area functions to get the universe of their design and But it's much more difficult to be arguing About how to remove the context and how to do that and the you know, so this is where I have to voice my What do you mean how to remove the context? Well, so so that one of the context that both of you talked about in the multi-verses and and the anthropic principle And I you know those are arguments about What's going on, but I can give you Examples of universes that are much more probable than the one we live in and examples of how do you know infinitely more probable than we live in Even though rare things happen, we shouldn't have happened right no no actually that's the important thing if it were really physics It would be great And one of my problem with my I've worried about multi-verses is that if we had a theory that allowed us to calculate the probability Distribution over universes. Well, that would require having a theory of the multiverse, which we don't have We don't anyone who talks about probability distribution doesn't know what they're talking about Because we don't have a theory yet. We can guess the problem, but if you're gonna do the anthropic principle You're immediately putting in probability institutions Well, you're assuming a selection effect, but you're and you're assuming you're assuming the probability institution But you don't that's the problem with the anthropic principle is it's always based on ignorance Because if you really had a theory you wouldn't have to use the anthropic principle anymore. You just calculate right large Can I ask a really dumb question? Yeah, I'm biting my tongue, but go ahead. Yes You agree that space and time come into existence. Yes, probably As you're well aware there are models of bouncing universes that I find particularly ugly That go through something at which you'd have to do plank scale physics But it could you could have imagined an eternal universe that that bounces and it doesn't obviate anything that I Talked about my point is you talked about the dark matter particle going through the universe in this space It's expanding right and time is growing Right what where the space between you me isn't expanding between my hands gravity between us to the audience, right? It's just that gravitationally. We got corrections going on. Yeah, what's the fact is spaces being created all the time, right? Yeah, so so But that that was the question right, but if I could get back to my question points much simpler How do you have dynamics without time? That's a wonderful question. I wish I had the answer But you know the point is when people talk about about in fact one of the arguments I look I've just come from Australia where I was having this debate with a Christian apologist And and the argument given of cause and effect that there had to be some Purpose because there has to be you know the cause and there has to be universal, you know The first mover all the rest of the stuff The point is you're absolutely right if time comes into existence at the same time is space Then the question of of what happened before is not a good question It's not a scientific. It's not a scientific question and but well I'm not sure it's not a sign of question It's not a question we can answer yet because we don't have an Understanding of that theory and then how time can exist. I don't think there's it you will agree with me that there's a Fast difference between things we don't understand and things that are not understandable Oh, absolutely, and so it's absolutely true that I can't as a physicist now Adequately discuss what I mean by universe is without time But that doesn't mean that someday one of the young people sitting here won't no, but I'm just saying that's a whole That's an obvious hole in the argument There's a what that's a what that is to me the most obvious hole in the argument I don't know how to talk about dynamics without time Well, you know you can imagine. I mean what you can you can imagine well you can imagine a super a Superspace, and I wasn't gonna say super strict argument where you have a Hamiltonian and things look like they're static But locally the dynamics when you take part of the system, you know how to do all that Yeah, but then you have a pre-existing Not space and you haven't you know our space you have a pre-existing entity I don't care if there's a pre-existing entity Our universe did not exist. It came into existence. That's the thing I wanted to discuss and I don't see why people are worried about stuff. We can't discuss We can we can discuss possibly how our universe came into existence Isn't that good enough to be celebrating on a nice afternoon in Minnesota? I like it But I want to know what happened beforehand. Well, I would too, but I don't know I think we're all happy to celebrate the idea that We've progressed enormously in recent decades and our understanding has pushed back the the frontiers of yeah of what needs to be assumed as Unexplained in within within our description of the universe But I think it's far from the case that we pushed it all the way back to nothing Well, you know, I think we're I think we're in agreement Because I've never because the point and in any sense of the word listen to carefully what I said and what I'd write I never say we've pushed our understanding back to nothing. We've made certain Postulates plausible and that is fascinating Darwin did not understand DNA when he or the Mechanisms of genetic mutation when he when he developed natural selection what he showed it was his eminently plausible based on the Fossil record and what he knew that all the diversity of life came from a single life form We now know much more and that what's great I mean and what I really want to do I don't want to emphasize is not overstate what we know But these the very fact that we can begin to address these questions should get people interested in thinking about them as scientists Maybe maybe I mean a position that I'm very comfortable with and have been for a long time is that the ultimate laws that govern the universe including both the laws and the Initial conditions and whatever substitutes for initial conditions in a final formulation will turn out to be simple and beautiful But it won't be zero equals zero. It'll be something richer than that Well, that's nice, but that's much more speculative than anything. I said it's a nice idea, but you don't know It'll be simple and beautiful. I mean it's a night. I'm glad it makes you happy I think it's what you're I think it's what they're groping for You know, but what's actually Equally plausible and I thought you were gonna say is that there may be no such thing as initial conditions Initial conditions may be inseparable from final conditions and they're very question itself may be a bad question And that's great. That's great and science will do and that may change the picture. Yeah But we don't know yet. We don't know yet and we let's celebrate and we were pushing things are pushing I'm pushing you You Question from the audience and contextualize it a little bit We've heard some talk about string theory not being physics because it's not testable Well, you would never say that I know Jim's your friend is is the multiverse theory physics What this person is asking is can we design or conceive of us an experiment or set of experiments to explore the Let me that's a really good question Are we just talking metaphysics or is it physics is the multiverse because in principle although It's possible in certain multiverse theories that universes can collide and then you'd know about it before you ended existence but But it could be that and it's quite likely that if if we're part of multiverse that will never have Direct causal information about the rest But I think it can be science in the following sense that atoms were science before we knew about them Namely before we could measure them directly one could imagine that we did have a very good theory That explained why there are three generations of elementary particles why the proton is 2,000 times everything electron et cetera et cetera et cetera why gravity is which we can therefore and it could be a corollary of that theory that in fact We can actually predict that inflation must have happened for example, and then we can make 50 predictions we should compare with experiments, but one of the Inevitable logical consequences that theory is that there's a multiverse so we can probe 49 Aspects of that theory and test them and then we're willing to say the one that the one equally logical Consequence that can't be removed also must exist so I I think that's science. I agree very strongly that in fact I think we have an extremely Useful and profound example of a theory that's very rich in Consequences that can't be verified And that's quantum mechanics quantum mechanics Works on wave functions that have much more information in them than we can extract even in principle So yeah, okay, we're in agreement Questions from the audience because I thought of it too during your talk This idea that during the inflationary period we had sort of a closed universe But it inflated so fast that what we measure appears to be flat and the questioner wants to know Is our determination of the flatness due to our measurements which which you showed Just we're close. It's really closed But our measurements think we make us think it's flat because it It's obviously a good question what we what we need to say and we often need to be more precise than me too And we tend to say things what we mean is that the measurable observable universe is Indistinguishable from a flat universe, but our unit, but the definition of universe has changed of course the universe What we mean by universe is now that which we which we are in causal contact with or ever could be in causal contact if or ever will be in causal contact with in the future and That's not everything and so if that picture I gave which is one version Which is that a closed universe is created if that's true then on sufficiently large scales That that closed space time is curved But but inflation generically although not universally but generically produces so much expansion that you that it's That the difference between will make will one is in the you know 50th decimal place or something So if we waited in a universe that lasts forever if you waited long enough You might see some evidence for that except in a universe that happens to be dominated by vacuum energy All that information will never be recovered because the rest of the universe will disappear Okay, we will close now and reconvene at three o'clock for father coins talk