consciousness to learn about more about this and our other upcoming virtual events. you can visit harvard.com and sign up for our email newsletter or check out the page harvard.com/science for more info. also be posting a link to our science research public lectures channel in the chat where you can view previous talks you might have missed. this evening's discussion will conclude with some time for your questions if you have a question for our authors at any time during the talk tonight. click on the q&a button at the bottom of the screen. we'll get through as many as time allows. in the chat. i'll be posting a link to purchase this way to the universe on harvard.com your purchases and financial contributions make events like tonight's possible and help ensure the future of a landmark independent bookstore. thank you to our partners at harvard university and thank you all for showing up and tuning in in support of authors publishers indie book selling and especially for science. and finally as you have no doubt experienced in virtual gatherings technical issues may arise if they do we'll do our best resolve them as quickly as possible. thank you for your patience and understanding now it is my pleasure to introduce tonight's speakers. michael dine is distinguished professor of physics of the santa cruz institute for particle physics at the university of california at santa cruz as one of the world's leading particle physicist. he has been a sloan fellow a guggenheim fellow a fellow of the american physical society and in 2010 was elected a fellow of the american academy of arts and sciences with ann nelson. he was awarded the prestigious soccer uprise for his contributions the field of particle physics. tonight he's joining conversation by fellow physicist lisa randall the frank baird jr. professor of science at harvard university. a member of the national academy of sciences the american philosophical society the american academy of arts and sciences. she is the recipient of countless honors and awards and was previously named among the 75 most influential people of the 21st century by empire magazine. this evening michael and lisa have joined us for discussion of michael's latest this way to the universe an accessible authoritative and up-to-date celebration of the core values of physics, which leonard suskin calls an extraordinary journal journey into what we know what we hope to know and what we don't know. widely regarded for his profound contributions to the study of time matter the big bang and what might have come before it michael diane intrepidly pursues answers to our greatest questions while giving us a tour of his illustrious career. i will end with final praise from the incomparable sean carroll who calls this way to the universe a rare event a grand overview of the leading ideas in modern fundamental physics presented by someone who is a true master. we are so excited to be hosting this event tonight without further ado. i am delighted to turn things over to our speakers. the digital podium is all yours, michael and lucille. hi there. hello, so. it's a pleasure to see you lisa and one of the things i don't describe in the book is one of the disappointments in my career is that this illustrious physicist didn't come to santa cruz when we tried to attract her some years ago. and weeks like this leave me i miss it. yeah. okay good. so i begin a little bit. so i so i thought i talked a little bit about the book and just read a little bit and then lisa can. asked me difficult questions so i was driven by to this to write this book by a desire to convey some of our present our current understanding which is really quite exquisite. of the laws of nature on both extremely small scales and very large scales. so in fact scales small scales meaning small scales much smaller than the size of an atomic nucleus and extremely large scales in meaning the universe as a whole. okay, and this understanding? though comes with the ability to formulate and what and wonder about very precise sharp questions. so the book is a combination of looking at things. we understand and the things we don't understand and that we would like to understand it sort of trying to understand or to appreciate which thing which questions we may answer with experiments and compelling theory in the foreseeable future and may be more removed. so that's kind of the goal and and as i wrote as i wrote this i so i sort of organized this in terms of hours of ten orders of magnitude. okay things that are very large and things that are very small and in the book actually have a little discussion about the orders of magnitude in terms of our experience of these last two years with covid. but rather than deal with that sort of depressing topic i start here just a little with a little reading about powers of 10 and sort of what got me thinking about some of this. so they said but powers of 10 need not always tells that the grim story. they are a valuable tool for thinking about nature. we humans occupy a tiny planet in a vast universe. at the same time there is a world of far tinier things molecules atoms protons neutrons and electrons. powers of 10 are also useful useful concept in these happier pursuits. in 1977 while a graduate student visiting the smithsonian institution with my brother. i watched the video powers of 10 by charles and ray eames a couple best known for their work in industrial design. this beautiful film summarized our understanding of nature at that time on the largest and smallest scales. starting with a couple enjoying a beautiful spring day occupying a space maybe two meters across in each direction. it explored scales progressively larger by factors of 10. parks cities states nations the planet the solar system galaxies and clusters of galaxies. it then proceeded in the other direction describing smaller scales parts of the human anatomy then cells atoms in the nuclei of atoms. it's summarized for me pretty well what i was learning in my studies to be honest. there was a good deal. i didn't yet know in that bill. a lot has happened in the subsequent decades. we understand nature at several powers at scale several powers of 10 larger and several powers of 10 smaller and we have clues to many more powers of 10 in each direction. i have been a witness to and in some cases a participant in many of these developments. telling the story of nature on this vast range of scales is the subject of this book. the story follows this progress and physics astrophysics and cosmology. i only occasionally mentioned the spectacular discoveries of the past century in biology medicine computer and cognitive science and other fields. so i want to describe that a little going to describe a little bit about sort of my career and sort of what what this is involved. okay, so i'm like lisa. i'm a theoretical physicist, but very interested in the outcomes of experiments. okay, and these advances which i've described have been the product of dedicated dedicated work of experiments experimenters and theorists. the cut like sorry partly the dichotomy between the two can be confusing one but one which will i hope become clear in these pages. well, i seriously considered a career in experimental physics as a student. i fell in love with theoretical physics. this was professionally a risky choice and some of my mentors discouraged me telling me that the competition was just too stiff. while i believe them and was by no means convinced i had the stuff for theory. i was in love with the subject. by graduate student days were spent studying phenomena at the smallest scales then accessible about 1/3 of the size of an atomic nucleus or about 10 to the minus 14 centimeters. about what about a trillionth of a centimeter? about a hundredth of a trillion of centimeters. excuse me. i have to confess that i was hardly a brilliant student, but my teachers had faith in me and i went on to do a postdoctoral fellowship at the stanford when you're accelerator center menlo park, california. here i was involved in interpreting experiments. i'm still smaller link scales. among my mentors were sydney drew a leading. oh, sorry a leading voice for nuclear arms control. and leonard suskin then it brash young theorists who had recently come to stanford. still though i had a hard time finding my way in that period the problems i worked on didn't really move me. after two years at stanford. i moved to a similar position at the institute for advanced study. the institute is an institution institution to exclusively devoted to theory and it is famed most notable. i'm sorry in part because of the faculty of its early days. this includes most notably albert einstein but also figures like jay robert oppenson oppenheimer who handed the atomic bomb project at los alamos during the second world war. john bun neumann and early computer pile of pioneer and george cannon the diplomat who shaped much of us policy relatives to the soviet union in the early days of the cold war. its current faculty including edward whitten nathan seibert one malthusena and nima arcane hamid are among the premier living theoretical in the world. in this environment i found my scientific bearings and started to probe questions beyond the level of our then current understanding. from there. i went on to five productive years on the faculty of the city college of new york before moving for family reasons back to the west coast joining the faculty of the university of california at santa cruz. i've spent the subsequent three decades there. so i talk a little bit about santa cruz and how beautiful it is and she would make lisa remind lisa why i wish she had come. but i go on a little bit and talk a little bit about about theory and experiment. so you just make sure. oops. yes. so this this book will explore many orders of magnitude beyond those which the creators of the powers attend video could contemplate. we will journey across scales both voluminous and micro miniature, but it will also travel the scales of time our clock will start at time zero at the big bang. on this clock our present instant is instant is about 13 billion years later. from our present moment. we'll look back to times when stars and galaxies but began to form one billion years after the big bang and further to the earliest times. we completely understand three minutes after the big bang when hydrogen and helium were produced in a hot cosmic soup. but we'll look back much for earlier the times for which we have only scattered bits of evidence when the universe was perhaps a billionth of a second old when matter itself may have been created. ultimately will peak behind the curtain of the big bang asking what might have come before and encounter controversial ideas like the multiverse? this idea provides a compelling explanation of one and maybe more than one. of nature's greatest mysteries it is even conceivable that we could find observational evidence for this bizarre possibility. and just a little more. let's see how we do for time. yeah, just another minute or two. i know i talk a little bit about the the difference between theorists and experimentalism what they do. and you talk in particular about einsteinus the pattern of the paradigm. excuse me of the modern theories, of course is albert einstein. einstein burst onto the scene in 1905 with three remarkable pieces of work. the two most famous of these are his theory of special relativity and the photoelectric effect for which he won the nobel prize. the average physics student is less aware of his work on the brownian motion, but this work did much to stimulate the rate just to establish the reality of atoms. gave a reasonably good estimate of the new of the number of atoms in the cubic centimeter of water avogadro's number. and how to profound influence not only in physics but in chemistry and biology all of these were combinations of some combination of pure thought and analysis of data from existing experiments. going to go on to talk a little bit about another theorist and the different style and that's enrico fermi who did who was both a theorist but also an experimentalist and perhaps the last great figure of that who really struggled both, but i do talk early about how you can particle physics in. yes. that's right it probably because and new and i do talk a little earlier about newton was also so so the book goes on. to talk about newton and einstein what did you do? what what did einstein do what was this theory of special relativity and then a good deal about his theory of general relativity. talks about quantum mechanics. it talks about our understanding of the forces of nature and how that's developed our understanding of the strong the weak and the electromagnetic force and how we finally have developed this thing known as the standard model. up and how we finish it how we got to this place? discusses the large hadron collider and the discovery of the higgs boson up and then a good deal about our just a discussion of our present understanding of the universe of its history and it's composition and again, how do we get there? up, then we bring raise up the book raises some of our outstanding questions at the moment questions that certainly lisa and i are you know why we could like worrying about so what where do large numbers in nature come from? there are some very bizarre large pure numbers and this is one of the great mysteries in nature. why is the more why is there more matter than antimatter? how did that happen? what's going on with neutrinos? there are a lot of mysteries about neutrinos. we know many things, but there are other things we don't and a lot of our current experimental effort is future experimental efforts are geared towards answering some of these questions. what is the identity of the dark matter? what is the nature of the dark energy? what is string theory about can it explain anything or everything as some of its proponents hope? up and what are the what what are the issues around the anthropic principle, which has been? sort of subject of controversy now for several decades, especially in connection with the observed dark energy so i think that's kind of why i have my way of introduction. you know, i'll turn it over. okay? so that's certainly a very comprehensive book of what we have today and it's exciting. i mean, i actually before we dive into the details. i actually am curious. i mean writing a book is a big endeavor. some of this isn't books that were there before and wouldn't i'd like to know like why you want to write a book personally like what it is for you that you wanted to do and also what you think the readers are getting that might have been missing before just how you would see it. how did you see this endeavor? well, i think i think i thought saw this endeavor from several perspectives one of which was with the discovery of the expos on i thought was a it was a kind of watershed moment. it's something that so this happened in 2012, and that's probably around the time. i started thinking about this book. be so it was so in some sense our understanding of the standard model at that stage was complete the exposone boson was as you well know. a sort of outlier in terms of you know it should look like it should be there, but it's awfully weird. in many ways. it's one of the things that the book discusses. and the and if the fact that over the subsequent few years some of the things we hope for for the lhc were not discovered that we work kind of at a moment. at a critical moment. and without criticizing other books, i think that there that that there are and i'm certainly not criticizing the books by you. the there are things i think that are worth conveying. to a general audience and that that i that i hope to convey so so i should say i mean one thing i really respect michael for and i think he's one of the few physicists. who really do both pure theory and really pay attention to experiment and model building and you know there really are these divisions that have immersion of field and somehow. you managed to ride over them and one of the things that was fun to read in the book was i mean, i i had dreaded the idea of having to commute everywhere, but how you were able to really take advantage of that and learn from your colleagues? and i think that was really nice in the in the fact that but that you were always open to that and i think sometimes reading the book is a little bit like, you know sitting in the car with you for a long time and hearing what you have to say and i think that's very nice. but i guess one question i have is some so a lot of the time i mean despite the fact, i mean, i do think that you know, you're basically the voice of reason on everything which is really nice. um, but you also are sort of taking the party line and most of the most of the questions so where would you say that you would be most deviating or most crit? of like where the physics community is. is there some place that you think is some unexplored or some unappreciated place to go. that's a good question. there's a sort of an issue of there there are various party lines and it's various points. i line up with one or another. i'm not sure. i'm not sure i am. so distinct that you could say this is this is dying alone. so so it one thing i think i should be curious to your thoughts at this point. it's a one of the things that i say sort of drove this was. we we have pattern that we're now almost 10 years since the discovery of the exposing. and we haven't discovered another major new thing but that's almost certainly telling us things. it's also it's also it's also disappointing. but there are various party lives there. are those who feel that we're that something new is around the corner. and those who feel that perhaps not. and and i and i think i present both sort of the nature of both viewpoints. and i straddle them. so my so for example i talk of the deal about supersymmetry in the book and for super symmetry proponents. the lhc has been a disappointment. but i give some reasons why maybe not so maybe maybe that's not the case. and and my colleague howard haber among at santa cruz among others pointed out actually some years ago that a higgs as heavy as the one we found. this hex about 125 times the mass of the proton is is only really is naturally compatible with supersymmetry at a scale. that's a bit too high for the lhc. and that's certainly gives me pause. and i talked in the book actually about some more outlandish ideas of my own about what might account for that. but but that's one example actually there i do have a question for you. why didn't you talk more about your own work engage mediation? i was surprised you didn't. right well gave me well and that she's nothing so much about gauging excuse me, excuse the audience for it. this is a technical thing having to do with how super symmetry breaking his communicated and michael did some nice very nice work on that along with ann nelson, right? this is an area where certainly this is this is areas where and i don't know if you remember this, but when i was visiting you actually walked into my office and said this is really interesting and i was working on technical at the time so i couldn't be bothered and then you went on into this really fabulous workout subject, right? this is actually something which i am the people i worked on with this is then nelson that's your related. unfortunately sure. it's not the right price. the well at the moment, i don't have a really a really good idea. it could be there. i don't talk about talk about it much. what i talk about instead is something a little more outlandish. which is why you might. with a lack of direct experimental evidence think that super symmetry has something to do with anything. and that i that i discussed in a another context in the context of the so-called landscape. where there's this picture that there that there are many that are universally really is much in some sense much larger than what we see. and that there are many people within that large universe many different possibilities possibilities for laws of nature. are realized and one of the issues in such a universe, is that most of those states? naively are not stable. they're radioactively decay and they decay fast. if our universe is unstable, it has to be still quite what businesses called metastable very nearly stable has to live at least 13 billion years and probably far longer. so what would that be and if you look for an explanation of that fact within ideas that are around for a landscape? good, the only idea i can think of is actually that there is some degree of super symmetry. so that's interesting that you say that because that's actually relates to another question. i would ask you more again more physicist and for this but one might also just argue that i mean and you've done very nice work on this subject to see how you could find find minima where you're in a weekly coupled regime of string theory, but as you know, it's very easy to be in the strongly couple of regime in which case we can't really say anything. so what would make you confident that it's something nice and something that week as humans can handle and it's not just in some messy strong strongly interacting state. that is it could still be our universe. it's not saying it's wrong but might be beyond what we can do at this point. i'm not confident. yeah something and it's something i talk about. so again, you asked me about party line. i don't know that there is a party line this question. it's actually interesting how little is said about that possibility because i mean it does seem like you know when people talk about the difficulty of finding string back you are with positive cosmological concept. i mean there it seems very clearly related to the fact that we just don't know how to write down stable theories that don't have super symmetry in them. and of course then it makes it really hard to have it because super symmetry would have generally zero or negative cost logical constant. so it seems that very that's that's a case for we should be a little bit more humble about it and admit that this could be our failing and not knowing how to find solutions. so right right. no, actually i've written not you know more professional context. i've actually written on this question recently right back. you have a colleague harvard who has discussed this questioning conjecture. that perhaps there are you know, there are not to sitter. but i should pause and say that. we measure this thing called the dark energy. this is a spectacular. result in it's a bizarre result. okay, it's bizarre because while there's a lot of it, it's 70% of the energy of the universe. there's a lot less than you might have guessed. there should be. and so understanding that has been a big puzzle. that's partly what? police says alluding to here. and the and in thinking about that one of the ideas that's around is something called the landscape and in fact what there's an idea do in part to one of lisa's harvard colleagues from irvafa called the swampland. which is a sort of suggestion about things that don't happen. string theories or in this kind of larger context and one of the things he said is that the cosmological constant like we seem to see doesn't happen, but this is based. on looking at the things we don't understand. and and i've thought about this a bit and written over on this topic a little bit and i think and i think you're absolutely right. that we are that we don't focus enough on the challenges of exploring. this question of what what? does string theory lead to things where we can really where we can actually calculate things? and of course, it's much more fun and interesting for us when we can and we learned a lot of things from that but when we make these grand statements like this doesn't happen in string theory. it seems like we should be a little bit more welcome. i i think the statements are really interesting, but i think they're also i think also they should be yeah taken with made with some humility with some recognition that we don't really know but it also gets to a larger question. which well, perhaps a larger question which is what ultim are there limits ultimately to things we to what we may be able to understand? yeah, that's never worth asking because like we'll just keep and answering things till we can't do it anymore. right? i think that's right and and and the lesson the historical lesson, is that that all that may be true but somehow we've managed to discover, you know, that's the flip side of this exquisite understanding we have we we didn't necessarily have any right to understand the things we do. and it's one of the things i talk about actually borrow a phrase from a colleague of ours tom banks. is is just in about quantum academy? it's really remarkable that people figure this out. it's you know, you know, you could sort of understand why we why we what you know, the newton would get it right and galileo. you know, we're programmed to you know. work by our evolutionary development to watch projectiles to throw things to watch it, you know watch things move, you know, the classical motion of objects is something where we're you know, we can have what's not surprising ultimately that we could figure that out. even if it took a long it's not easy. quantum mechanics is really weird. there's nothing in our you know in our there's no evolutionary obviously evolutionary imperative to understand how atoms work. and they worked in very strange ways. but it is it is also worth noting though that i mean and i know that you know this but quantum mechanics wasn't just discovered in a vacuum. it really was we were i mean physicists at the time we're facing an abundance of data that i'm just couldn't be explained. and one thing i like to say is, you know, a lot of people were like, well did the greeks have the atoms and for the greeks it was sort of you know, these eternal unchanging objects that were indivisible and really the way quantum mechanics and atoms are discovered is that they are divisible and that they do change so there was a fair there were fair bit of clues and i think that's important when we think about this question of how much we can do with theory that there was all this data. oh, absolutely. absolutely. i totally agree, but i also i also would refer back to people like neil sport who really did worry that maybe this would be beyond human understanding. and i'd say that in some sense depends what you mean by understanding when people even though we can all do our calculations and we all teach the course and solve our problems. that's we still at some level. we are still bothered we think. oh, yeah, absolutely. absolutely, and but i would also i would also say the fact that they're we certainly were capable of organizing lots of data stay in the night in the early part of the 20th century. but we you know, we then had this rather sort of bizarre accident of people like heisenberg and schrodinger writing down these equations, which worked. after following up on earlier work by bohr and others which it were given empirical formulas for things and certainly also following up on plunk and einstein. but but but the fact that we sort of put this together and as you say it's also true. that there are things that as much as we do understand about quantum mechanics and as much control as we had and as you say as we can do calculations with ridiculous accuracy there are things that are puzzling and disturbing and whether there's some larger understanding that might ultimately emerge i i wouldn't i would be i would not be so immodest to say no. um the other really striking thing i think is that you know the people working on quantum mechanics they were daring but they were all so conservative in their ways so they would believe the step that they needed to believe to do it. so, you know, there's this idea that light is quantized but is are the quanto real then are the quantum actually particles and then and you know, so each other our photons really those particles so i think but and i think that's just the way it is and i think it's a i mean, it's look it's one of the most beautiful lessons in how science is done that you don't get everything right the first time and also there are different interpretations that all can simultaneously work. and so i guess another question i like i mean so, you know, it's some level we're both effective theorists, you know, we sort of deal with what we can see at this at these energy scales, but we know there could be a lot going on beyond so i guess it's a little bit related to the question of you know, do we really need to solve things and strong public? so do you think there are things that we're going to miss by being effective theorists. do you think there's some fundamental ways of thinking about things that we would be missing? oh, that's a good question. i don't know that i have a good answer. i think that's perfect. answer is definite maybe. okay. imagine there's no problem with that. i just was curious if you thought about i mean, this is your grandson about you know, right? i think so, for example, if i could turn this around a little bit. so one of the one of the things that's in some ways very discouraging. is this landscape idea so as much as i've been sort of intrigued by it, it's also discouraging in the sense that this does suggest that there are there's a there are very serious limits to our understanding. and i my in my own thinking i sort of turned this around a little bit. so i mentioned this issue of the stability of the universe, for example. so i've tried to turn around like your discussion of all the questions that we know won't or that at least at this point. we have no idea if why would they be resolved by a landscape kind of thing? right? right, and i think that was a really important point which makes it no, that's right. so so i think there are you know, so i think what i've tried to do, and i think i think you asked in the beginning sort of what what was driving a little bit and a little bit was this to try and be sort of honest about what what were puzzled about and what may be the limitations of our what? you know what we can hope for and what might be the limitations of our ability to understand so i'm gonna switch gears for a a minute because i think we have been losing some people by talking about this so that i think it's fun. so i guess i'm going to ask just a couple of this more general questions. one question is so i'll give you a choice of questions, so we'll run out of time. eventually one is just are there books that you liked in terms of physics? i mean one book that i liked a lot and was the first three minutes. i thought that was a really nice book to tell us where things are going on. i was curious if they're you know, or even in writing this book. did you look at other books and find any inspiring but another question i have is um sort of about the state of the field. and do you see the polarizations increasing or decrease to answer that question? i'll go into more detail about what i yeah, i'll start with i'll start with with books. i looked at a lot of books as i was thinking about this and of course through my life before my giving my career in my career there looks like i've read i would have also certainly mentioned the first three minutes and i think a lot of us, i'm sure you also as you wrote. your various books thought, you know as a model for what one might like to achieve a sort of a book that is honest and serious clear not not, you know if you talk to people who've read it not everybody gets everything but a lot of people do. so it's a wonderful book weinberg has a number of other books. he had a book on. dreams of a final theory which was written in the era of the ssc? so as the ssc was on the brink of cancellation, so it was partly addressing. so for those of you who are actually young who's who are still a read books the ssc was a superconducting super collider, which was a mega version of the large patron collider that you probably do know about that's it and it was a great the great promise for american physics, i guess back in the 80s and 90s. yes, right and and i sell some stories about that and those of you who are at least old enough to have been fans of the west wing may have once seen a west wing episode which was about the cancellation of the of the ssc but but in this book so the book was as a to a large degree address that that it addresses other issues actually and i and i quoted a little bit. one of the things i talk about a little bit this is a sort of a little off that our main topic here. but but one of the things i talk about a little bit is the idea that of and it gets a little bit to what lisa was saying. this this fact that we can understand nature is something quite remarkable. and and it has moved a lot of people einstein certainly spoke about this and others. weinberg has a has a fabulous remark in that book, which i quote which is basically to say that the more we understand about the universe the more it seems pointless. and i don't know the universe seems pointless not understanding the universe. yes. yes. that's right, and i don't necessarily agree, but it certainly again in terms of presenting various party lives. this is a this is this this is what i when i present, i'm an admirer of your books. especially what passages okay, i wasn't fishing care, but thank you, but i think it does it does it does achieve some of the things that i hope to achieve with this book in terms of explaining what we understand in a very comprehensible way as then going on to discuss more speculative ideas. and i think the important thing wring these books which you obviously were very clear and it's just to really be clear when it is speculative. it's fine to talk about things. we don't know but not to present it as as a no, so i have another question for you since this is, you know grant of your career. associate or a young graduate student today, would you would you want to be doing theoretical physics still and if you were what directions do you think you would start off? and you don't have to have an answer to that but if you do would be really interesting. i think i think what i would probably hand student my book. and say these are some of the questions. you know, i could talk a little bit about some of the directions which which people are i'm asking you are starting off as a student. if i was starting up assistant there was thinking about the advice i give to is to know i'm asking because you the advice you give to yourself the advice. i would still probably give this advice to myself i it would be it would be. tricky, i think that that on the one hand though, and i mean we have exactly this. this tension between the fact that we understand a lot. we're our understanding is so much richer. then when i started out as a student. you talked about you mentioned. that's what is a slightly tactical term. you and i are sort of effective field tourists. what that means is that we look at. but theories that are adequate to describe the phenomena we're looking at and not necessarily to describe much more. and they're loosely. what we can do now with that knowing that knowing that they're an approximation and they're copy more fundamental physics underline. so knowing so just like newton's laws or a an approximation to something larger encompassed by einstein and einstein is presumably an approximation to some something else. so so what we understand that that level is so much more impressive. when i was a student or someone later when lisa was a student. and and and so the subject richer i think intellectually. then it was years ago at the same time the you can worry about where where are the areas of progress? so a lot of people you and me included. up have been our investing some of their effort in thinking about the dark matters so we know there is this called dark matter. um, and we know it and we know there's about five times as much of it is ordinary matter and we don't know what it is. and and answering this is a is one of the certainly one of the great questions. whether we're guaranteed to succeed. is another matter. and and ideas are a little bit all over the map. so i so i have a hard time. so if i were entering the field and entering that area, i'm not sure exactly what i would. right. i mean i i think i mean so my personal view on that is that it's the right attitude because we really do have no idea so they should be all over the map because what we want to do is make sure that they're if there is a way to observe dark matter, which is very challenging. we don't miss it. so by thinking broadly about the possibilities, we're more likely to exactly right exactly. what i say to people is what i most appreciate or ideas that cup for experiments for example that can explore broad swath of possibilities and and there are and there are certain things like that out there, but i think this is this is a challenging area to have an impact. so in terms of as a career choice you know, i i i'm not sure if it you know, i'm not sure how that would work. but absolutely another question, which is again kind of hard question, but what do you think we take as obvious today that we're going to will change. like all right. well good question if i really knew the answer to that i would you know, well, it's not necessarily something that we it could be a really hard problem that i mean a lot of the really interesting problems as you know, and i know or ones that are just very hard to attack directly. so we you know, we have take this side roots but then in the end we might think some big things going to happen. yeah, well, i would say, you know, the is certainly. an example of something where people are exploring things that a few years ago people, you know what the conventional wisdom was. they're not possible. so for example one interesting idea, and i'm not sure how seriously to take it which people are exploring again is the idea that the dark matter might be might be some form of so called primordial black holes black holes, which were formulated early in the and whether you know, you know if a number of years ago, the conventional wisdom was no they can't be. but that wisdom is certainly been challenged recently. and and i think that you know that if that's true. if that should turn out to be the case if we could establish that was the case. that would be quite remarkable and would tell us about aspects of the early universe which otherwise we probably would have no access to so on the other hand, i mean just to be clear. so dark matter. it's just matter. that interacts with gravity like ordinary matter, but just doesn't interact with lights. it's not made up of the standard model particle physics stuff. it's it's really something beyond and but what i always find shock is that people are so upset by it because why shouldn't it be there? i mean it's and and if it was there it would be really hard to find it because it's something that just doesn't interact with us a lot. so it's by it's very nature. i mean the only thing that's really surprising i would say is that the amount of dark matter is so comfortable to the amount of ordinary matter and that that is definitely a mystery but again, we wouldn't know about it if it wasn't true. so i was gonna say the same thing what's remarkable about the dark matter in the dark and the dark energy both is that they're all? in this moment in the history of the universe. all they're all comfortable. one of the things i talked about in the book is in fact, of course. with the dark energy is taking over. so is if we into the future. the dark energy will become the dominant form of energy. and whether you know so again, so there are people talk about this they called cosmic coincidence or so on in these these things are sort of part of the part of the mystery. so i'm going to ask one more question, which you can use to answer or not. and then i'm going to switch to audience questions. so behind you you can see the text and i know that you are somewhat religious and how do you think that's affected you as a physicist in your thinking? and be curious i would okay. so so to elaborate on that i am i'm not particularly religious, but i am in a family where some people are and certainly have friends. who are and i'm and i'm sympathetic to of religious viewpoints, but it hasn't in terms of my work. it's something i keep separate. and i think i think you would find among. people of various religious persuasions, even those who are who do describe they usually are able to keep these things. separate as i say i sometimes them i mean it gets back i think to this remark i made who alluding to einstein and others who would talk about the wondrous thing about nature is that we can understand it. and and i sometimes hold that view and sort of that might be sort of quasi religious. and then of course i quote this. remark of steven weinberg's which is to say just the opposite that the universe is just kind of a mess and why you know, we understand it more and more and there's no driving rationale. so i i take the cop-out approach, which is the effective theory approach which is that the universe is interesting on our time scale and our lives and that and that's it in terms of the ultimate purpose. who knows but but as long as it's interesting to us, it works. i mean i talk a little bit. i mean the other side of this is i i talk a little bit. and in fact you mentioned books and i actually did not read this book before i wrote mine, but there's a book by katie mac which talks a great length about this question of what is the ultimate future of the universe. it's something i first heard about in a colloquium actually by one of my astronomy colleagues the person named greg bluffer. many years ago the future of the universe as far as we could tell it's pretty bleak. so it's not we won't be around to know about it, right? that's right. that's right. so so, yeah, so so i i don't find. i don't find much comfort or soul is saying they afraid i'm as much as i go. thanks for answering that i'm sure a lot of people are curious. so i'm gonna turn to audience question. so one question, it's a good very nice one is so what would you think the next great discovery will be oh, i wish i wish i wish i knew if you think about sort of. i could be an example of a possible discovery. okay, so one of the things that people certainly look at at the large hadron collider is the possibility that there are beyond the higgs particle we found there are additional weeks particles. so that's a that's a subject of serious effort. if that were found so i would sort of bet against it. if it were found though, it would be really remarkable. so for example in my mind, this would sort of kill the sort of landscape idea and the anthropic idea there at least combined with that so i should say the anthropic ideas this idea that some of the laws of nature are the way they are. because otherwise there wouldn't be people to know about it. that's kind of an extreme statement of the law. it's usually statement stated a little more conservatively, but that's sort of the idea but there's no need as far as effective field theories. like we said i or concerned for our second hinks to account for the things that are critical to making structure in the universe building stars and building. planets building people and so i think this would really so would be really remarkable. just this thing because i would think that we should go on but there's so many things that seem useless in our universe that i don't know why we have to discover something else useless to to be able to our generation. of course. i don't know your generation, of course the smallness and variety of these things. yes. i mean we've learned to i i'm well, you ask at some point you said at some point. i'm following the party line. and as i say, i'm following a variety of party reliance and i should and i shift to which one that various chapters of the book. yeah. i'm just being provocative there. that's okay. okay. um, this is a good question too. and what's the most important find you hope is realized through observations of the new web observatory. and i think we know we think well that will be but i will let you answer that. well, there are few of them. you actually probably have better ideas about this than i i mean, i think but i think you know, i mentioned at the beginning this this time a billion years after. big bang when structure starts to form and we're going to learn a great deal about that. we're going to confirm ideas about about about how about how? how the initial small i mean i should back up and say that you know, one of the things that's that's very remarkable. is that the universe on? i should back up even further and say one of the things that einstein and earth in the early people who thought about cosmology did which when i first read about this as a student seemed outrageous was they assumed the universe looks the same in every direction and in every which way you go. so the universe is supposed to so called homogeneous and isotopic and if you look our algebra window that looks crazy, but in fact at some level it's it's very true on very large scales. universe is very smooth. okay, and one of the kind of thing that to understand how structure forms how the non smoothness forms is really one of the great questions in science. and web telescope will certainly give us insight into that. i have to say i'm also i'm also excited about things like extra solar planets on which it will do more, you know. remarkable things and so no, it's an exciting instrument, but you probably probably have comments and thoughts beyond my i mean there's certainly, you know crazy thing. i mean that you can imagine it might give us some insights into the first black holes, which is something you mentioned. um, but i think on the whole what it probably will do we'll give us some insights into the beginning structure formation, which of course and just just for to be clear. i mean, that is an amazing story. i mean and that really is one of the stories of the last few decades just how all the stuff around us came to form and you think about it's quite amazing, right? we start off with radiation. that's the same in all directions and somehow that gets perturbed in ways that some stuff collapses into galaxies and then stuff stuff collapses enough to form stars and we end up with the amazing structure we have today and so, you know, and i think a lot of the time one we're looking at these cosmological questions. we know what happened relatively recently, but actually people love to talk about origins, but that's actually a thing. we really understand like how did the universe actually start? how did actually begin, how did life actually form so anytime we can approach that. it's always right, you know, who knows what we'll find. oh great. yeah. this is a great story. i mean and when i okay, so again going back to when i was a graduate student. i i read a textbook a wonderful textbook we talked about steven weinberg's first three minutes at the same at the time you wrote that you wrote a beautiful textbook. and in that textbook this problem of how structure form is described as almost as one of the great mysteries of science. it's presented there. is this this deep and it is one. question, which is in large measure salt at least there are many aspects of this problem of this problem. we understand and this. you know one of the pleasures of being at santa cruz through the years is a good deal with the work was by physicist and astronomers and it's anniversary. yeah, and i want to agree with you on that in addition to being a beautiful place. i mean there is a remarkable collection of physicists there and including howie who's just celebrated which was really nice, but it also realize it was definitely a certain era of physics when this was possible when people could really learn from each other and talk to each other. and so in terms of books my colleague joel premack who was certainly contributor to a lot of these developments also has wrote several very nice books and he likes to explain things. yeah. so so and this is kind of leads a nicely into a question. i'm so taking questions of backwards order in some sense, but but i might even attempt some of this ballet youtube it says i heard you called say inflation in the standard model a computational standings until theories and display an understanding and this is being compared epicycles and so i want to really emphasize here because it's a really really important lesson about science and about almost the way we understand almost anything. then when we say standing it's more like what we were calling an effective theory it is a rigorous way of doing calculations with the knowledge that we have. and it means that there could be more fundamental theories underlying these things and that's what we're looking for. in fact what we're always looking for are deviations from these theories that make beautiful predictions to see how far do we have to go before we find that they're not right so that we learn about something that underlies it so i've talked enough so i'm gonna let michael take over at this point. yeah, well, this is a certainly a subject. of the book and i think lisa's characterize it well, we know what we're looking for. we know we know from observations a great deal. and for example, we we already know much the james welch webb telescope will tell us more can characterize what what this phenomenon of inflation was in several ways, but there are many there are a number of things. we don't know and and in some ways this is exciting. this is a an area for you know, this is for this is a clue for what's going on. it scales much shorter than those we can currently with accelerators. for example. and i should say that lisa and i passed had a very pleasurable collaboration on some issues of this this kind. so but so i don't think it's like epicycles. i think people are well aware when they write down models that the models have are inadequate and in some ways that there's much that's learned even from precisely from the united inadequacies of these models. and and to be clear, they're adequate describe anything that's been measured so far, right and we're looking for measurements that can tell us why they're not adequate. yeah, so they get more to be inadequate in the sense that they have features that are just on a unsatisfied there might be unsatisfying rather than you know, they're not yet, but people write that people's models if they don't explain the data, they don't get published. sometimes they that's true. okay. so, um, i think we might have somebody from another planet who's asking questions because there was first question from the anonymous attendee was what type of reader did you have in mind when you wrote this book marvelous book i should say and the other one is do you think we will find extra terrestrial life or have we already so i think there's someone in the audience who's clinging? he's from another planet and is really interested in your book. so i'm gonna phrase the question is what do you think are going to be the things that really stand out? i'm actually i was recently asked to be part of the new golden record, which is going to send some information out there on some some mission. so what is it? so what would you say is the thing that you think of all these things? um is what would we want to convey? and i think the fact that we can do science and that we can get these answers is definitely one of those things. so i'm gonna ask you that question and so start with apologies the anonymous attendee for sort of you know, it's a good question. i haven't you know, there's a history of this as you know. right. that's why they're doing the past people sent up things on satellites and one of the things that they tried to do was conveyed the idea that we are a matter universe not an antimatter universe. by proposing an experiment that you could do with a particle known as the cayman. and this must have happened i guess in the 70s. and so there's so i think i'm pretty confident that we're not going to be picked up by any antimatter universes. that's something actually talk about in the first things i worked on that was important was the canvasics and cp evaluation. i have to say it was like one of the hardest things to explain to someone who lives next door to me the idea that we were going to have this communicated hilarious right now forgetting which satellite like this went up on. yeah, but but one of the one explorer that went out into deep space. so probably, you know, it's a good question and probably you want to have you might want to have a biologist or a cognitive scientist or various other kinds of people at the table to think about this. but probably he'll be lots of different way to convey. some way to convey some of the things that we understand. you know this a sort of assumes that you know, the encounter will be with a society that was driven there's a big difference right between life and intelligent life. that's true life and speaking of intelligent life. i think we're very very lucky to have such intelligent life write a book and present it to us. so thank you michael. i think i think we're coming to the end of our time here. so and thank the audience for your great questions too and and it was um, you know, i don't i have to say even though i wrote these books. i don't read them. anybody. your book was a pleasure to go through is really easy to and corpus love interest. okay, well congratulations and i really enjoyed this and it's the i say it's nice to see you and i hope we are. something that's going to be in a situation where we can visit the person. very nice. you should definitely come visit too. okay, fantastic. okay, so i'm just gonna are you taking over benjamin or should i just yeah, i'll close us out again. thank you so much both of you for that. i also should say thank you to the harvard book store for continuing to support books and books about science. it's it's you know, as we see all the things in harvard square disappear. it's so great that it's still there. so, please keep it up. yeah, yeah, it's the square has changed quite a lot these last couple of years. and again, thank you both for this fantastic presentation. thanks to all of you out there for spending part of your evening with us. please learn more about this incredible book and purchase. it at harvard.com. i put the link in the chat a couple times on behalf of harvard bookstore the harvard division of science and the harvard library all here in cambridge, massachusetts. have a good night. keepyou don't have to hide behid that thing. come on out. yeah, come on. come on. i know you coming. they wouldn't have he was i love i love my friend don. he was hiding behind a thing like i was gonna introduce him. like y'all didn't know he was coming. first of all on but on behalf of the book festival at tulane and my fantastic wife cheryl and walter isaacson who here today give him a big round of applause. they and and allison and lindsay and a whole bunch of bucket load of people been working on this for three years suffering with covid and