Into the Impossible With Brian Keating - Francis Halzen: Catching Neutrinos at the South Pole (#276)

Episode Date: November 30, 2022

Francis Halzen is the Hilldale and Gregory Breit Distinguished Professor of Physics at the University Wisconsin-Madison and principal investigator for the IceCube Neutrino Observatory, the world's largest neutrino detector, he is the Director of the Institute for Elementary Particle Physics, and the Hilldale and Gregory Breit Distinguished Professor at the University of Wisconsin-Madison. A theoretician studying problems at the interface of particle physics, astrophysics, and cosmology, Halzen has been working since 1987 on the AMANDA experiment, a first-generation neutrino telescope at the South Pole. AMANDA observations represent a proof of concept for IceCube. After six years of construction, IceCube became operational in 2010. IceCube searches for neutrinos from the most violent astrophysical sources: events like exploding stars, gamma ray bursts, and cataclysmic phenomena involving black holes and neutron stars. The IceCube telescope is a powerful tool to search for dark matter, and could reveal the new physical processes associated with the enigmatic origin of the highest energy particles in nature. The most important result from the IceCube was the clear break-through observation of high-energy neutrinos (about 100 times more energetic than the particles accelerated today in the world’s most powerful machine, the LHC at CERN) in 2013, from as yet not identified sources outside the Galaxy. This discovery has stimulated the planning and development of even larger neutrino telescopes, both at the South Pole and deep under the ocean. https://user-web.icecube.wisc.edu/ Connect with me: 🏄‍♂️ Twitter: https://twitter.com/DrBrianKeating 📸 Instagram: https://instagram.com/DrBrianKeating  🔔 Subscribe https://www.youtube.com/DrBrianKeating?sub_confirmation=1 📝 Join my mailing list; just click here http://briankeating.com/list ✍️ Detailed Blog posts here: https://briankeating.com/blog.php 🎙️ Listen on audio-only platforms: https://briankeating.com/podcast Subscribe to the Jordan Harbinger Show for amazing content from Apple’s best podcast of 2018! Can you do me a favor? Please leave a rating and review of my Podcast:  🎧 On Apple devices, click here, https://apple.co/39UaHlB - scroll down to the ratings and leave a 5 star rating and review The INTO THE IMPOSSIBLE Podcast. 🎙️On Spotify it’s here: https://open.spotify.com/show/2G3PRMUhxGQkyQzLiiCqlf?si=8656119458df4555 🎧 On Audible it’s here : https://www.audible.com/pd/Into-the-Impossible-With-Brian-Keating-Podcast/B08K56PXJX?action_code=ASSGB149080119000H&share_location=pdp&shareTest=TestShar Other ways to rate here: https://briankeating.com/podcast-  Support the podcast on Patreon https://www.patreon.com/drbriankeating  or become a Member on YouTube- https://www.youtube.com/channel/UCmXH_moPhfkqCk6S3b9RWuw/join Learn more about your ad choices. Visit megaphone.fm/adchoices

Being a physicist, from all objective point of views, is a miserable career. Yes. And I don't have to state the reasons. The only reason it's worth doing is you just enjoy this. You're obsessed by it. You love what you're doing. And so if you do it as a job, it's going to be very, very disappointing, I think. So don't underestimate yourself until...

I went on this crazy adventure of Amanda and Ice Cube. I always live with the insecurity that I didn't belong to the circles I moved in, which I think must be true for almost every graduate student. Just get over that. Hello and welcome to another fascinating and ultimately endearing episode of The Into the Impossible podcast. This is such a treat to present Francis Halzin, who not only is one of the greatest physicists living today, but met the greatest cosmologist, perhaps, of the 20th century,

the man who came up with the Big Bang Theory, according to some accounts. And that's, of course, father, Georges Le Maitre. And I know I'm pronouncing that right because he was Belgian, and today's guest is Belgian too, and that's Professor Francis Halzin, who had that honor of knowing Le Maitre, and also teaching yours truly for a brief quarter while I was a student at the University of Wisconsin-at-Madison,

home of the Badgers, the fighting cheeseheads. I love my time there. I miss my time there. He's the second professor to come on the show from the University of Wisconsin-Madison. My PhD advisor, Peter Timby, was on about a year ago, maybe for our Father's Day episode a year or so ago. And that was great.

But I never had Peter Timby, my graduate advisor for a professor, unlike Francis, who is today's guest. And you'll just love his ability to explain to entertain, to recant as a raconteur, and share his inimitability. knowledge of the cosmos, of particle physics, really from the beginning. And he's so sprightly. He hasn't really aged a bit, maybe physically has some more gray hairs, but not mentally. He's as sharp as ever. And he's really been through enough to give anybody gray hairs. You'll hear

about the moments of panic that led to moments of great relief, perhaps, but only after decades. And it really reminds me of some of the interviews I've done with Ray Weiss and Barry Barish that you can find in the back catalog. So please do, really, you won't want to miss the slides that he shows what you can see on my YouTube channel, Dr. Brian Keating on YouTube, we have about 75,000 subscribers. It's free to subscribe. You can join if you want. There's a tiny membership you could pay if you really wanted to. But I don't do that for this. I do that. What I do for really the privilege of talking to these credible minds and thinkers and contributors to what I think of as the highest expression of culture of what we do as human beings, which is to work

together to build scientific tools that allow us to understand where we find ourselves in the universe. And it's incredibly important to me that, uh, that, you know, you are on this journey with me because, uh, when I mentioned to Francis that, uh, that I wanted to have them on, he, he recognized this podcast and this podcast wouldn't exist without you guys. And the support and love you give. And if you want to show some more love, again, these are all free things. I only do free stuff, really. I don't ask for money. I feel like I get paid enough as a humble, uh, servant of the University of California with the newly re-elected governor, Gavin Newsom, my boss, that we will really have enough to sustain ourselves intellectually

just with a tiny bit of support. And so one way to do that, subscribe to my YouTube channel where you'll see the slides that he showed, and really you'll see the animations and videos as well. And you should also leave a review or rating wherever you're listening to this podcast. And if you do a review on Audible or on Apple Podcast, I'll read it, and I might read your name

like I'll do today with Marco H. Kras, from the good old USA, whose review is entitled, Inspiration for Curiosity and Problem Solving, great podcast with a thoughtful host and a variety of interesting guests that died deep into thought-provoking subject matter. Fresh takes on cutting-age research and age-old questions alike. That's exactly the vibe. I'm going for, thank you so much, Marco. And I'm just so thrilled that I have you all on this journey.

And you won't want to miss joining my free email mailing list, which comes out twice a month, basically. It's easy to join, easy to leave if you want to. It's free. And you may win some of this stuff, which is. a high-energy particle at some point. These are little tiny meteorites, which used to be fragments of a failed planet

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some of this phenomenal space schmutz. So for now, sit back and enjoy a tour, a journey, a voyage that will take us to the bottom of the Earth, the South Pole, and to the deepest reaches of the cosmos as we explore the fascinating, mysterious world of the only form of dark energy we know exist. Sorry, did I say dark energy? I meant dark matter.

Even more mysterious to some, and that's neutrino physics. Come along, let's go with Francis Halson, into the impossible. Any sufficiently advanced technology is indistinguishable from magic. Well, it's not every day you get to talk to a hero of physics, of modern physics. someone whose roots go back quite a way, someone who's been a leader in the field of astrophysics, of particle physics, who's an educator and a communicator of science, but also who is actually, I think today's guest is my first ever guest who is a professor of mine, although I took his class as an adjunct student.

Well, I was at the University of Wisconsin, and it is one of my personal heroes. This is Francis Halzin, who is a Belgian particle physicist, although he's been in America probably more than half of his life. He's the Hildale and Gregory Bright, distinguished professor at the University of Wisconsin-Madison. He's a director of the Institute for Elementary Particle Physics, and he's the principal investigator of the Ice Cube Neutrino Observatory, which is operated at the South Pole, Antarctica since 2010. Before that, there was Amanda. Francis, it's a certain treat to be here for me to host you here, rather. And I just hope you won't share the grade that I got in your club.

Please don't tell my audio. I don't want to. I don't think my bureaucracy, my administration is so good that I would be able to produce it. Well, it was one of my favorite classes of all time, not to mention the fact that back then it was rare that professors wrote the textbook that was used for the class. I think I had that only with Leon Cooper at Brown with one of his quantum mechanics books. But to take this course on particle physics with you, and it was such a treat. And I thought we'd start there, Francis. We always start, we have on, you know, we just had on Martin Rees, Lord Martin Rees last week, and he spoke about his book. And we always do a scenario called judging books by their covers, where we look at the cover of your book, and we judge it. And we judge it.

it and how did you come up with the name and hopefully entice a tenfold increase in book sales instantaneously. So the book we're talking about is called Quarks and Leptons. It was a wonderful, wonderful book that I had there. We'll show it on the screen. It's written with your co-author, Alan Martin. I don't recall much about him, but certainly taking it from you was quite a treat. So, Francis, can you help us judge Quarks and Leptons by its cover? How'd you come up with the title, the subtitle, and the cover illustration. The title was actually, first of all, I must say this was a long time ago. And that's the amazing thing about the book, right?

People don't realize now that this book was written a long time ago and that the W, the Z, the top quark, none of these things, the Higgs, none of these things, the Higgs, none of these things had been discovered. You know, like the whole book is kind of prediction of the standard model. And in fact, the book was in print when the W was discovered at Sun, the weak intermediate boson. Wow. And so the editor called me and said, you can still change things, you know. I've read a newspaper.

And I said, there's nothing to change. and he was kind of worried that he had been part of some huge gamble. But the title is kind of embarrassing because although I think it was really, the books were really written in parallel. O'Koon, famous Russian theorists, wrote the book, Leptons and Quarks, that came out around the same time. time. So it's not that original. And the illustration that you have on the cover, what does that

represent? The only thing I remember is that I actually made it. And it remembers, you know, jets were something rather new then, you know, quark glue on jets, the concept. And so I know that it represent like a jet made in deep in elastic scattering or something like that. It's amazing that I cannot remember. No, I think that rings true. And actually, we have had on past guest Frank Wilczek many times. And he cites that, the discovery of jets at least, not by Ice Cube or anything personally, but he cites that as the kind of signature achievement of his career and of work that

that particle physics as a community has led to. And I wonder, you know, if we could pivot from this wonderful book, which I learned a great deal from, and I still make reference from when I have the task of teaching to young people as well, as well as your style. So I want to first take a step back. It is rumored that you knew La Maitre, the famous Belgian Catholic priest, the progenitor in some sense of the Big Bang. Is that true, Francis? I barely knew him. He, he died when I was doing my undergraduate thesis. And so I could tell a mattress stories for a long time. But I'll only tell you two.

Because, of course, every interaction I had to assume is now legendary, right? But I'll only tell you too. He had a computer. He built himself to solve Friedman's equations. And it was a big room with vacuum. tubes. And that computer, I mean, your state of the art at the time was only used during the day. And we actually, we mean another graduate student and I, Remo Gastmann's, we would actually break into the room and use the computer at night. And we used it to calculate Feynman diagrams.

Veldman had just discovered the methods to calculate Feynman diagrams by computer and so I think we may have been the first people to do this after Veldman discovered it. The other story is that when I was an undergrad the matter would arrive in a limousine at a physics building and, you know, he was an important person, and he couldn't walk anymore, barely walk. And we put him on a chair and then carried him to his office on the second floor.

And it's only later that someone else who was part of the institute told me that that was actually Le Maitre. I had never made the association. Wow. He was not very visible. He was retired. then, you know, he came in very rarely. And by the way, he was not famous, right? As you can imagine.

He was famous for being a cardinal and for his role, maybe his role in Vatican, too, but I don't think so, actually. Yeah. So he was, I mean, you know, the status of cosmology at that time, right? So it was just at the time he died, as you know, when the microwave background was discovered. That's right. And one of the things that's always impressed me about him and many others is that he was an advocate that the Pope, was it Gregory. I forget who it was in Vatican.

But they attempted, the Vatican attempted to utilize the predictions of the Big Bang, at least as a motivation for Genesis. And I was actually just in Galileo's house in Florence, our Chetri, Italy. And of course, you know, he was refuted by the Catholic Church and repudiated his own ideas under penantly of death, basically. But did you ever get the sense? Or was there anything in the Belgian physics community, perhaps, that, you know, spoke of what was his true, you know, emotional investment in the Big Bank? Did he have one?

Or was he able to detach being a scientist from being a scientist from being a. of theologian. Yeah, I cannot tell. I was not, you know, I never got any class. He basically was at the end of his life. And so we had really no interactions scientifically with him. But the fact that he denied that the Big Bang had any connections to creation, that's, I think, well documented. Yeah. You read this bio, there are a couple of biographies of this, which I've read of course. And they clearly document that he didn't see, he didn't make any connection to religion. And when we were getting ready to start recording today, I wanted to kind of get your,

you know, take on the obligations of a scientist in terms of what he or she should do, quote unquote, should do. And I think, you know, LaMaitre certainly took that role seriously, but, you know, he had so many hats that he was wearing, you know, pontifical hats maybe and science hats. But what's your philosophy? We'll come to more kind of big picture questions later after we review Ice Cube in your career. But what is your view of what the obligation, if any, that a scientist has to explain things to the public? And then do they have to kind of be careful how they explain things because maybe the public doesn't understand what they're doing? Well, I think I, from this point of view, I am a very practical person.

I don't think I'm on a mission of anything. And on the other hand, I think that even we are supported by the public to do our science, we owe some return to them. And, you know, I have never done an invitation to talk about my work to anyone. At any level, any student of any age, I always react positively to an invitation to discuss my work. And that's, I think, an obligation we have. Beyond that, I think it's very dangerous to, you know, our expertise, is science. And it's actually, even within science, it's a very limited expertise. And I think

it's to the advances of scientists that they stick to their expertise. And that's certainly something I always do. Yeah, I always say that, you know, the problem that we are scientists deal with is that sometimes we become political scientist and you start to delve into politics. No, that's not a good idea. And it also. also it hurts science, right? Because then science begin to look like something that it shouldn't be, and it's not. Right. And there's a danger in what we call audience capture that you have to only do what your audience wants you to do. So on this channel, a lot of times people want me to only have people that won the Nobel Prize or only talk about aliens or only talk about

dark matter. And I have to be very careful because I get a lot of attention from the videos. that are popular, but that isn't necessarily the totality of what I think a scientist should be interested in. So anyway, I think you're absolutely right. And I want to ask you, you know, first we can go back to maybe a moment in your career that was a little bit, you know, maybe perilous. I remember being in Madison, as you know, from 97 until Peter Timby, my wonderful advisor, who's been a guest on the channel. So you're my second guest from the University of Wisconsin, Madison, the great Badgers, cheese state,

Dairyland state. So I had nothing but fond memories of being there. When I had Peter on, we were kind of, you know, speculating on the notion as a scientist to deal with uncertainty. And I remember you building, you preparing to build

and starting to build up Amanda. And it wasn't just the technology. It wasn't just the theory. It wasn't just the science. It was the people. It was the team that you built, which is, you know, which is unrivaled.

And it seems to me you've been working on this for so long. Was there ever a time that you had doubts in yourself, that the funding would come about, that you might not succeed as you've done so spectacularly well with Ice Keep? Did you ever have a moment of panic that you just were so terrified that project might not move forward? The whole story was a story of panic. You got the right word. you know from the beginning when people thought that this was a very cute idea but that it wouldn't work well that's what we taught too so but it kind of started as a you know as a game it didn't cost that

much we were piggybacking on the on the south pole infrastructure that already existed to a large extent but then NSF started to fund the project i actually borrowed a lot of money from the university of wisconsin and i was deep in depth to both NSF and the university and we had never seen a neutrino, not an atmospheric neutrino. And so, and of course it's because we really didn't know whether turning ice in a Schrenkov detector was possible. It took us like a decade to figure out what the ice was like. We couldn't put it in a test beam at Fermilab. And so, you know, the most exciting, among all the panic moments, the most exciting, the most exciting, moment was not when we discovered cosmic neutrinos, but when we finally observed atmospheric

neutrinos, because that I felt we have delivered. Now it's up to nature. And even afterwards, I thought, you know, if scientists, the English liked to gamble, right, scientists wrote an article that gave us six to one to discover cosmic neutrinos, against, of course. And I remember not feeling very well when I read this. But then I always thought if we built something that unusual, we'll do something interesting. The big surprise, actually, is that we are doing neutrino astronomy and not something totally different. We do different things as well. But the other moment of panic is when we finally got the courage to publish in

science that we had detected cosmic neutrinos. And weeks later, we were declared breakthrough of the year in 2013. And I must say that was also a moment of panic. And I remember the press conference. And the only thing I thought about, this, how do we run this backwards if this happens not to be true? Right. And I lived with that panic for quite a long time. In fact, it's only now that we see sources, right, since 2017, that, you know, I, I sleep better at night.

Well, that's a, you know, a 30-year journey to... But this was a wild ride, right, right? this whole story of ups and downs. And yeah. So what was the role of the South Pole in this? Could it have been done somewhere else? There are alternative approaches, but none even closely related in success to what you've achieved.

No, that was, it's a unique opportunity because you need clear eyes. Clear eyes exist elsewhere, but you have to build a sophisticated detector in a remote location and without the South Pole stations I mean this would not have been possible remember we started in a very modest way and nobody would say oh there by we always wanted to build a kilometer cube detector can you imagine someone saying ah Halseman wants to build a kilometer cube detector let's build a station somewhere above the glacier in green and give him the opportunity. It was pure serendipity that these two things came together,

the clear ice at the South Pole and the station being there. Nobody would have built it for us. No, and it's such a unique location. I've been there twice. I actually prefer going to McMurdo than going to the South Pole, but that's just me. A lot of people love going to the South Pole more than anything. and the results that you've garnered, yeah, it is serendipitous in a way, but it also took a lot of

foresight by you and your team to recognize and persuade. I think one of the least appreciated aspects of a scientist is his or her ability to persuade, and that includes persuading undergraduate to work in his or her lab or a funding agency or to get tenure or to get even a professor job. It's so hard nowadays, but then building a team. So it's not enough to have right idea. Like the idea is just kind of the table stakes, you know, to use a gambling analogy. So when did the kind of that subsiding of that panic? What has been, I mean, of all the things that Ice Cube does, and we're going to cover it a little bit of technical detail, because my audience is the most sophisticated in the known regions of the multiverse that we inhabit. But I want to ask

you of the technical breakthroughs, could Ice Cube have been done, you know, 50 years ago, let's say if there was a, you know, very, very young Francis Halzin as a graduate student, could you have done it 50 years ago or were there technological breakthroughs that you and your colleagues and understanding of the ice has made? Yeah. It depends. It's a difficult question. It's a question I've never answered.

One of the challenges, I mean, maybe the biggest challenge was to, build a hot water drill. And that was such an unusual problem. It was also an exciting problem because, you know, you don't go to school and they teach you about hot water drills, right? No. So in Wisconsin they do actually, right?

This was done by a group in Wisconsin of engineers, professors, graduate student technicians, anyone who could contribute, contributed. And it was very exciting. But I think, you know, it's car wash heaters that make the power. And the nozzle is very sophisticated.

It was designed by an engineer. But it could have been done before. No doubt about it. I am not so sure about the data acquisition because, of course, we could have used the Amanda technique of just sending analog signals over the cable. that brings down the high voltage, right, that powers the photomultipliers. So, but the data acquisition of Ice Cube is a bit more sophisticated. You know, we capture the signals in the ice, transform them to digital and then transmit them.

And so that was, in fact, the chips that are used, where the PhD thesis of a student of David Nygren. at Berkeley. Oh, wow. So that was really a bit beyond state of the art at the time. Of course, now that technology looks like archaeology, right? But this was, the Berkeley design was made in the late 1990s, because it was all in place when we submitted a proposal in 99. Right.

Wow. So it could have been done, it probably could have been done earlier, but in its present form. And for the discoveries we make, the electronics, I don't think we could have done it with Amanda analog signals. It's pretty essential to have the technology that Nygren and the Berkeley group developed for the data acquisition. I want to ask you, because I knew you as a as a student. of yours, albeit not as a graduate student, I think that would be a great treat. But as a student

in a class about for advanced undergraduates and graduate students and particle physics, why do we conflate scientific ability with educational or pedagogy ability? In other words, someone who's a pilot may be extremely skilled at flying, but we don't ask him to like teach flying necessarily. Although you, and you can, you can. can actually teach flying with, I'm a pilot in my side hustle to pay the bills here at the State University of California. But I want to ask you, why is it that we do that? Do they do that in Europe? Is that common, you know, that we have an expectation that because Francis or Brian are good at scientific research, that they're also good at teaching? Or is that a mistake?

Well, this is one of the things I feel passionately about. never had a time to do much about it. But I think that, you know, the graduate school that exists today at American universities is, in a sense, unfortunate. It still lives in the days that you take courses and learn all of physics and then do research. First of all, you cannot learn all of physics anymore. You cannot even learn all about some specialized subject in physics. No.

So the way I have everything I know, and the Belgian system at the time allowed you to do this, everything I know I've learned by doing research. You get interested in a problem. You have to solve it. You learn everything you need to solve that problem. And that's how you learn. And you remember, by the way. And I think that's the ideal way, trying to get a background of all of physics before you start doing research is an illusion, which we are still living in in our present system of graduate schools.

Yes, yes. And it seems to be, you know, sort of strange how the European system influenced the American system. you know, the Germanic kind of emphasis on research. And now most of the Ludwig Boltzmann or Max Planck Institute, they don't teach, as I understand it. So it's kind of ironic that the educators of the American system, they don't do any education of their own anymore. So I wanted to talk a little bit about the technical details

and the theoretical underpinnings of Ice Cube. And you've been kind enough to prepare some slides. so I'll let you get set up to share the screen. Your summer starts now with Memorial Day deals at the Home Depot. It's time to fire up summer cookouts with the next grill, four-burner gas grill, on special buy for only $199. And entertain all season with the Hampton Bay West Grove seven-piece outdoor dining set for only $499.

This Memorial Day get low prices guaranteed at the Home Depot. While supplies last, price is invalid May 14th or May 27th, us only exclusions apply. See homedepopo.com slash price match for details. Okay. So, you know, we want to detect neutrinos from space because we want to do astronomy with neutrinos rather than with photons. And we know how to detect neutrinos.

This is an experiment in Japan, in a deep mine, and it's a huge tank of water and light sensors. and that's how you detect neutrinos. The problem with this is a beautiful experiment is that the theorist in their wisdom told us that, and by the way, I'm not blaming anyone, it was one of them, told us that this experiment is 10,000 times too small

to do astronomy and catch the tiny flux of neutrinos that reaches from the, universe. So to make a long story short, we build a detector that instead of water, made out of water, is made out of ice. And the phototubes are distributed throughout the ice. And according to our wisdom, as theorists, it probably had a chance to detect cosmic neutrinos, but no guarantees were given. And so what you're looking at, of course, is not a real picture. But so if you go under the South Pole, you stand, the South Pole station stands on three kilometers of ice.

And you go one and a half kilometer deep. There are strings with the light sensors that you saw on the walls of the Japanese experiment. And so the strings are a kilometer long. and there are 86 of them. So the light sensors between strings are 17 meters apart and the strings are 125 meters apart. And 86 of these strings fill a volume of ice with light sensors. This idea, by the way, was born in 1960,

the Russian physicist Markov came up with this idea. So the idea is certainly not new. So the challenge was to melt these sensors into the ice. And so we developed, that was the first big challenge. We developed technology at Wisconsin to do this. And the second challenge was, was this ice good enough to act as a particle detector? And that's a long story. And the story is told in this slide.

And I would spend the rest of your time if I went through this slide. But we made our major breakthrough when we realized that the light, blue light in ice, travels over 100 and sometimes hundreds of meters. So this is a compacted snow of 70,000 years ago. It's ultra pure. And even in a lab. you cannot build a block that transparent to blue light. So we didn't know that.

That was pure serendipity. So these two things being solved, we build it and took data. And the idea is you can imagine your block of ice here. And you can imagine that it's like one and a half kilometer deep. It's dark. So what we do is we look for particles coming through the earth. And only a neutrino can come. through the earth, nothing else.

And that neutrino not only comes through the earth, it comes through your detector. But occasionally, like one in a million, will hit the nucleus in the ice, the nucleus of hydrogen or oxygen, and make particles. The particles it makes in the nuclear interaction, they are charged and they make the light glow.

That's called sharenkoff radiation. And if this is a muon neutrino, then it makes a particle called the muon, and it travels for kilometers in the ice. So that muon, you can detect from 50 meters to at high energy 50 kilometers away. That's not quite practical. but you get the idea that your detector is bigger than what you instrument. And the other thing is you have a telescope because you not only detect a muon, you can point it back

because the muon travels at the speed of light almost. And the light in ice travels at three quarters of the speed of light. So it's like a speedboat that outruns its waves. And so you get a shock wave, like the bow wave of a boat, and it points back where that muon comes from and where the neutrino comes from. Right. So we built a detector, and here you see an event. This is a neutrino that comes 11 degrees below the horizon and streams through the detector. It deposited inside the detector 2,600 TV of energy.

So you must remember the highest energy beam at CERN in Geneva, it's 14 TV. So this particle deposit just inside the detector, 2,600. And by the way, I mentioned atmospheric neutrinos, which are background. This event is much too heavy to be produced in the atmosphere, much too energetic. And we can do astronomy these days with about 0.3 degree resolution. If you didn't get a picture here, you see on our online display, you see the muon going through the detector with the speed of light slowed down by the computer. And so that's the method. And so what we did is we measured neutrinos from the cosmos.

and you see here, this is the energy that the detector collect the neutrinos from the cosmos and as a function of the energy of the neutrinos. And the data points you are looking at are electron and tau neutrinos. And this actually is the flux of the muon neutrinos measured the pink band. is the flux measure with the method I just displayed. The other data points, we measure electron and tau neutrinos with a different method, but you see they agree. And so this is the muon flux through the earth,

and you see how we measure the flux from the atmosphere when we reach the threshold of the detector, which is 100 GV. then we get more and more background in atmospheric neutrinos. And when we reach someplace like tens of TV, then you see the atmosphere turns off and we see the excess flux that was shown on the previous picture. This is a measurement now close to 10 sigma.

And we have seen atmospheric neutrinos in at least four totally different ways. that's the status of ice cube. I have a few slides to show what our results are. Yeah, please do. In fact, our most important result, we actually never advertise, but I'll do today, and I always personally do. I showed you the flux that we receive from the universe,

the energy flux in neutrinos. It's what astronomers call new F new. And of course, we receive, we detect fluxes of gamma rays. Here you see this peak, this huge peak, that's the CMB. Very familiar to my host. And then you go through, it dominates the universe, then you go to different waves, X of light. This is ultraviolet light, x-rays.

gamma rays, but then the universe turns opaque to gamma rays. They turns opaque to gamma rays because they cannot make their way through the microwave background. The microwave background filled the universe, stops them from reaching us except from our own galaxy. Right. And actually, Francis, I have to stop you there. Yeah, go ahead. Did you know that the namesake of your professorship, Bright, the Bright Wheeler

phenomenon, which is the interconversion of photons to positron-electron pairs. That was only recently detected. And actually, I made a video about that. I'll have a link to it in here. Thank you. Yeah. That was really exciting. Right.

Anyway, please go on. Yeah, the pair production. Yep. Per production. So these photons per produce, make E plus and minus pairs interacting with the microwave photons. And so they lose energy. So the flux disappears.

And that, of course, is the resonant a detre of neutrino astronomy. You see here, once you are beyond this demarcation line, you can only do astronomy with neutrinos. But the other interesting thing is, if you look at the flux of the gamma rays, the flux in neutrinos we observe is actually larger than the flux in gamma rays. and nobody had ever expected that. And that's also why we found it with only two years of data. And so this is an interesting fact, which still requires some thought and explanation. So now we have to find where these neutrinos come from. So here is a picture of one year of neutrino data in Galactic.

coordinates. So that's the sky. We see neutrinos. We have 10 of these pictures for 10 years of data, more now. And we know from the flux we just measured that in this map, there are 138,000 plus atmospheric neutrinos. 200 of them are actually cosmic. But you also saw what I explained. And if you go to very high energy, the atmosphere cannot deliver neutrinos anymore and you are in business. So if you look at the very highest energies, it look like this. These are various methods with which we collect that is cosmic neutrinos. But notice one thing, we don't see our own galaxy. Now, in any other wavelength of light or any other way of doing astronomy,

the first thing you see are the sources in your own galaxy. We don't see those. We see flux at the 10% level of the flux that reaches us from the cosmos. So there are galaxies outside or sources outside our own galaxy that overpower the flux from the nearby sources that produce neutrinos in our own galaxy. We have a paper that's on the review in science that will address this question. But just to remind you, that's what the galaxy look like in visible light, and we don't see the galactic plane in neutrinos.

Now, for many years, we made the cosmic neutrinos were discovered in 2013. Of course, the game was where do this particle come from. You know, we know their direction now to 0.3 degrees. And we did all kinds of things. But I'm going to just tell you about the latest. We actually discovered a source in a multi-messinger campaign. pain in 2017. It was an active galaxy. And I'm going to tell you what happened since then. We collected, we looked at our 10-year map and we published a paper a year ago and you are

looking what's in this paper. And forget the red, just look at the blue. The blue, this is the upper limit on neutrino sources, we didn't see any by analyzing 10 years of data. And you see the dashed line is our sensitivity to sources as a function of where they are in the sky. The northern hemisphere is on the right, zero is the horizon, and the left is the southern hemisphere. And we discovered, however, that our map after 10 years was not quite symmetric, isotropic anymore. And it was due to these four sources that we detected at almost 5-Sigma discovery. But that's before the look elsewhere effect. After you imply the look-elfare effect, the asymmetry in the map was still real,

but the evidence for the source is not so great. NGC,068, almost reached three sigma, with all trials taken into account. So the question was, were this limits on fluctuations? And I'm not going to, I'll just give you the answer. They are not fluctuations. We went to a campaign to calibrate the detector better, to do improved reconstruction.

using machine language. We improved the point spread function of the telescope, abandoning Gaussian approximations. And with the conspiracy of all these improvements, we answered the question I just post. And here you see NGC, 168 before the improvements. And then you see we calibrate the detector better, including calibrating each phototube individually. And you see how this is the source, the astronomical occasion.

You see how with more statistics we move towards the source. We point better at the source. and our final evidence is at the level of 4.2 sigma. Now, this is the result of a blind analysis where we mathematically can compute all our trials. So this is a real, this is not a social construct, it's a real probability. And so I can sleep well at night with 4.2 sigma. So here, another way of looking at it, this is a picture of NGC,000, It has this very active hot corona surrounding the central black hole.

And here you see the simplest way to look at a signal. You see this is the direction of NGC, 1968. The oranges are background from atmospheric neutrinos. And you see if you approach the source, the number of neutrinos increases. So we see 88 neutrinos pointing at the source with on average higher energy than the energy of the background, which you cannot see on this picture. So that was certainly very exciting. Here you see, let me just look at the top one.

these are three analyses that confirm each other. They are slightly different. They actually use assumed different spectral indices. But you see here the 5 Sigma discovery, which I showed before, and you see this is pre-trial.

You see NGC sticking out of it. You see a source TXS05 or 506. That's the source we discovered in 2017 because it produced a neutrino of enormous energy. that telescopes in a multi-messenger campaign pointed back at this source. N of source PKS 1424 plus 240. So the top three sources reappear with improved significant.

Interestingly, one of these sources here on the fourth row in this analysis is NGC 4151. So here we are, you know, in 1950s, 43, Sefer discovered broad spectral lines from these two sources published in this paper. So we reproduce these two sources in neutrinos. And now I could go forever and forever again. But so all these sources are sources that are actually active in radio. so they have an active core, and the core is opaque to gamma rays.

So none of the stuff we see is accompanied by gamma rays. The gamma rays are shifted in the dense target that produces the neutrinos. They are shifted to MEV energy, X-ray or below. And so this is where we stand. So in fact, this is multi-messenger astronomy plan B. How do you look for sources that don't emit gamma-Rae? That's not so simple, actually. So I'm waiting for ideas.

I think that's the end of this. Yes, so this is NASA picture of NGC, 168. Yeah, sorry, this is it. And thank you so much, Francis. So the other thing I wanted to pivot to was a recent paper that your team had in nature about a limit on quantum gravity. And I wonder, first of all, do you have any slides about that?

Yes, I do. Okay, great. I do. You know, I want to emphasize that we are about 350 people analyzing Ice Cube data. What I presented, the astronomy I presented, is probably only about one third of us are doing this. I don't know the exact number. but people are using this detector, of course, to do glaciology. There was a time in my life I published more glaciology papers than physics papers.

I'm very proud of it. And a large fraction is looking for dark matter. That has been a long haul. Amanda was actually originally very much motivated by the fact that we would have discovered dark matter. matter if the Wimp Miracle had happened. And unfortunately, it didn't. So, that's right. But we are still looking. And people use the neutrinos to do tomography of the earth, geology. And it goes on and on. We do neutrino oscillations competing with Fermilab, with a different part of the detector that I didn't emphasize here. But, uh, one

One of the things we have been doing is given the opportunity is so unique, we have been looking for quantum gravity. And this is a very old story. There is actually a whole community in physics that involves looking for quantum gravity, which is kind of merit to the alternative, which is looking, for violations of special relativity. It's, it's, it's, it's, they are embed together, as you will see. But it's easy to explain, you know, our neutrinos have a mass. We detect them for over cosmic distances with enormous energies compared to neutrinos

we make at accelerators. So the fact that they have this tiny masses is very important for physics, but it's totally irrelevant here. Our neutrinos are like photons. And so if they travel through the vacuum from the sources far away to here. And even though they have a flavor and oscillating to each other, by the time they arrive here, they arrive as packages of electron, tau, and muon neutrinos in equal numbers.

so this is boring. Unless this thing happens and I wrote an article two decades ago and a German artist made this picture and what does it show?

Well, it shows what the vacuum that our neutrinos travel through looks like if you marry quantum mechanics and gravity and so if you marry quantum gravity

and quantum mechanics and gravity, you know, the sheet that matter transforms that Wheeler always talks about, that sheet now has quantum fluctuations. Yes. And so this is a picture of what the vacuum looks like. Our daily vacuum we live in now, what it looks like when it has quantum properties

and quantum fluctuation, which it does have to. have. The problem is that in our present vacuum we live in, they are suppressed by the Planck scale. So they're tiny. And if I transform the Planck scale in a distance, they're 10 to the minus 33 centimeter. So you need neutrinos or photons with wavelengths of that magnitude to become sensitive to these fluctuations. And we do. And we already, were aware of this and set the first limits with Amanda. I don't know if we want to go into that much detail.

We should. Yeah, I mean, the audience loves to hear the details. How do we look for this? I mean, clearly, our experiment is ideal to look at these particles traveling through this quantum fluctuations over cosmic distances. That's how we get sensitivity. This effect is very small, but we can build it up by having the neutrinos travel for a very long way. And so what you basically do is you test whether the particles satisfy this,

the classic special relativity dispersal relation, E-square equal p-square plus M-square. And that's the property of these neutrinos. when they travel in absence through just vacuum. The M square doesn't really matter at our energy, but this relation between energy and momentum is modified when the neutrinos start to interact with the, they start to feel this quantum fluctuation,

and that we parameterize as a power series, you know, a sum of an equal 1, 2, 3 and so on a distortion in energy that's characteristic of the Planck scale. So the quantum gravity scale or the scale of the violation of relativity because you see

E square not equal to p square can also be caused by violating special relativity. So we look for terms like that when the neutrinos propagate. And so it's a few line calculation.

So what actually happens? What happens is that particles with different energy now begin to propagate violating to a different extent is E-square-E-square-equal p-square relation.

And so the particles with high energy get a time delay proportion to particles with lower energy. The ones with high energy interact more, so they get delayed. And the time delay is given by the power of the term you're investigating, this power series. You know, we typically look for an equal to term. and then so we look for a term of time delays that are proportional to the energy square. But the time delay builds up the larger distance you look to the source.

So even though this is very small effect, if you build it up over long enough distances, you can become observable and it does in the case of ice cube. So as it says here, integrate over very long distances. So here is an example of one version of this analysis. And I always like to quote to show it with a quote from Michael Turner, who said that unlike Newtonian physics, general relativity will not last 200 years. So we're trying to prove him right. But you see here, we can put limits of delta C over C, a change in speed of light,

or an influence of the gravitational field, phi, on the propagation of the neutrinos. And you see, we're sensitive to the variation of order 10 to the minus 28. when the coupling to the gravitational field is strong enough is given by this angle, which is, I won't explain. So we are putting limits on violations of relativity of 10 to the minus 28. Now, if you listen to how I explain this, so you have these wave packages of three flavors

traveling through this quantum fluctuations. So the different flavors can undergo a phase shift when they interact with these gravitational fluctuations. And that creates flavor oscillations made by the interaction with this field, with this quantized field. And that violates, can vary. the prediction I made two minutes ago that we have wave package of equal flavor arriving.

And so what Ice Cube now does is it, and that the paper we recently published was one version of this. So this is the number of tau, mu, and electron neutrinos in the beam. So we have to discover this red dot. If we are anywhere else in this plot, we have discovered something. Lorenz violation, quantum gravity. You can interpret it any way you want. And so our present, this red dot with our present measurements of the three flavor scenario as a systematic error, which is given by the,

by this butterfly. But so if we can establish violations of these principles, new physics, by ending up somewhere, anywhere else in this diagram. And so this is our present measurement. This is the error bar at a 68% level. And we are doing a dedicated effort similar to, or even bigger, to what I explained for finding the sources of the cosmic neutrinos to squeeze these error bars.

We are actually going to put in new strings upgrading the detector in the season 25-26, which among other things will exactly focus on making this a small ellipse around the red dot, and hopefully maybe not. So we will see. But this is a high priority of the experiment. I have two more slides to remind you of a fun fact. You may remember that the opera experiment discovered the violation of relativity many years ago. Yeah, it was actually the year before the Bicep 2 results came out, which made us very nervous that we made a wonder. Yeah, exactly. And you can see on this slide, there is another way to test relativity, which was pointed out by Glashow.

That is if your particles move at the speed of light C prime, which is bigger than the speed of light, they carry an excess energy, MC prime square minus MC square, and that extra energy, they can radiate away. And that radiation, for instance, can come out as a plus a minus pairs. But when they radiate away their energy, it means they lose energy. And at the time, Glashore and Floyd Stecker pointed out that the highest energy neutrinos had actually too high energy and were inconsistent with the opera observation. Of course, I don't know whether the opera has an observation disappeared. before the paper was published.

But our highest energy events seen at the time were inconsistent with that violation of relativity. So it shows we are doing something real in a very concrete way, right? And actually, yes, I didn't know about that. And Sheldon was a guest on the podcast about two years ago. And I neglected to ask him about that event. Well, there's so much to talk to Sheldon about as there is a view. Yeah, I mean, how do you pick your subjects, right? Yeah, we could go for hours.

The only thing I want to say about the Lorentz invariance, and we're looking for it in the polarization signals of distant objects as they rotate or do not rotate, and you can look for birefringence types of effects, as you talked about with the ice. By the way, you know, it's a clear quantum, but what I was explaining before is the analogous of gamma-raised traveling to. a crystal, right? And they can exchange their polarizations. So it's a pure quantum effect. But it's very straightforward to look for it. Yeah, it's very interesting. And I guess the only, you know, kind of, you know, critique that I've heard is that the results are somewhat model dependent. I mean, this SME framework, which I've used in my papers before as well, is very, it's very specific to,

a particular class of, you know, it's like they say about non-Gausianity. It's like saying it's a non-dog animal. Well, there's a lot of non-dog animals in the world. Right. So how do you address those, you know, kind of... Well, my answer is that this is the least model dependent you can get, right? If you have a model, you can always reinterpret it in terms of this power expansion. That's right. This is actually a standard method that was pioneer by... Weinberg, right? To, to, you have a theory and you

parameterize the deviations in terms of operators of different dimensions and N are the dimension of these operators. That's amazing. So I think that's the most model. So it's the most model independent

you can get that. And any model we can reinterpret in terms of these results. That's right. That's right. Well, thank you so much for that, Francis. I guess the topics I'd now like to turn to is what comes next for Ice Cube. There's rumors of advanced Ice Cube structure that will come about. Can you talk a little bit about the status of?

Do you have any slides on that? No. I don't have any slides on that. That's fine, yeah. So I, but it's very simple. I mean, if I had given a one, one hour talk, and I often do on Ice Cube, the only conclusion any reasonable listener can come to is we need better angle resolution, we need more statistics, we just don't want to

deal with a few sources, we need more sources, and what do you do, you have to build a bigger detector. Yes. fortunately, we discovered when we build and design, when we build ice cube, we only had a vague understanding

of how large the absorption length actually was. Because Amanda was much smaller, right? So we had never seen ice and light propagating ice over a kilometer distance, which was necessary to measure an absorption length, which at the bottom

of the detector is 250 meter for shrink of life. So it's just incredible. And so we were conservative, but now we know we can space our photomultipliers further. And so this 125 meter distance between strings of photomultipliers, we're going to increase to 250 meters. And then we can instrument 8 to 10 times the volume with the same number of photomultipliers. Wow. So 10 times the volume for the price of ice cube. And of course, you know, all the data acquisition, which I discussed at the beginning, all that is improved and much cheaper.

And so we really think we can build a next generation detector for the same cost as the original one. We actually have designed this detector and submitted a design to the Decadal Review, who endorsed it. So it's not a dream anymore. At least unlike the first dream, at this point we know what we're doing. It's not a gamble anymore. You said this place was steps from the water. We just haven't found the steps yet. How much did we save?

Enough. Enough to get lost. Or you could book a stay with Hilton. Welcome to your ocean front room. Just steps from the water. The Hilton sale is on now. Book on Hilton.com or the Hilton app and save up to 20% to get the stay you expected.

When you want savings, not surprises. It matters where you stay. Hilton, for the stay. that's wonderful well congratulations with that and of course you know it's this a phenomenal treat to see not only the success of your projects and the leaders under your leadership but all the young people that have come out of it my friend nathan whitehorn at ucLA and and of course sharing the the space with you and and your team down at the south pole um with uh so many young people it's always so energizing to be down there and not to mention the hot tubs, which were, which were quite great.

I never got to go swimming in one of the hot tubs. Yeah, I always show a picture of the collaboration at the end of my talk. Yeah. But it's actually a picture and it's incredible, the age of our collaboration. I have theories why this is, but I won't go into it. It doesn't matter. The other thing I have to say is, and this was always emphasized. by the late Trevor Weeks who discovered, who developed gamma ray astronomy,

earth-based gamma-ray astronomy. Trevor Weeks used to say, astronomy is not like particle physics. You need many telescopes. It's not like discovering the Higgs, you know, in principle. One detector could maybe have done it, but you need two. Even there you need two. And so astronomy, the sky is a, big. There are many problems.

With a smaller telescope and the right idea, you can contribute. And so people pick, I think the biggest compliment to Ice Cube is that people are now planning and building detectors, building in Lake Baikal, building in the Mediterranean, building off the coast of Vancouver in Canada, and planning a detector. in China. Yeah. So there are many more to come, I hope. It's truly breathtaking and inspiring to me as one of the five or so co-leaders of the Simon's Observatory, which is equally sized and is also hoping to shed some light, no pun intended, on neutrinos.

And their whole is dark matter and as a very important budget and energy budget, in the cosmos. So, for instance, we speak a lot on this channel to young people, graduate students, postdocs, undergraduates. And one of the favorite parts of the show is when I ask kind of non-scientific questions, which I call the existential questions, are the final four. And I'd be honored if you'd answer some of them, if you don't mind right now. I am fearless, but I'm probably not a good or certainly not a typical subject for this, but let's go. There's no difficult subject. So yes, let's go into the impossible, the final four questions I ask. So they typically have to do with the distant future, both yourself and

of humanity, perhaps, and then advice to your former self as a young person, because as I said, we have a lot of, mostly men, I'm trying to boost that up, but mostly young men interested in science, technology, but we are open for all. So the very first question that I always ask is, what would you put in what's called your ethical will? In other words, what would you like to impart as wisdom that you've learned? Not scientific necessarily. It could be anything. It could be to your children or great, you know, grandchildren or many, many generations down the line.

What piece of wisdom guides you, if any? Well, I think with the advantage of not just looking at the future, but looking back, I want to come back to my years that I was at Lemaître's Institute writing my undergraduate thesis on quarks. And imagine this was 1967, 8, 1967, actually. And so I alluded to the fact that if you worked on cosmology at the time, time, you were kind of a crack portrait. Yes. La Maitre was not a famous person except for the fact he was a cardinal.

And he had been, you know, the president of the papal academy and so. But I actually, my undergraduate thesis was on Quarks, another topic that nobody would touch at the time. Right. And so first of all, the first of all, the first. message is just do what you're interested in. You cannot be successful if you do physics as a job. And I'm kind of at the edge of the generation where actually physics wasn't a job. And that was wonderful. I'm afraid to say the time is gone and it's rightly gone.

So that's one message. The other message is how to You know, I don't have to predict or be a visionary. Look how exciting science is. Can you imagine that in 67, you worked on quarks and jets and on cosmology and the Big Bang? You were not taken seriously. In fact, you couldn't get a job, even if it was a job. And look where we are now. I mean, a black hole and a big bang and a quark jet are as real as this cup of coffee on my desk, right?

Nobody questions this anymore. And this happens in my career in one generation of a physicist. And I have no doubt that this will continue. It may not continue in the direction that we are now talking about. it may be off in a different direction. But I'm sure it will continue. Science will always be exciting. Yes, absolutely.

It's as you'll hear in just a second, I'll say what my next, my next quote comes from Sir Arthur C. Clark, who said that any sufficiently advanced technology is indistinguishable from magic. And I want to ask you, what knowledge, either from your personal career or from all of science or maybe, I don't know, anything from philosophy, theology, who knows? What piece of one sentence or the shortest amount of words that you could possibly describe

the thing that humanity should be most proud of? Well, I always limit myself to the expertise I have. And not just humanity, my generation should be proud of what, we just talked about. Yeah. And that's something to be very proud of, I think. I agree. Yeah, my late great colleague Hans Parr, did you ever know Hans?

Did you ever know Hans? Yes. Yes. So he was a great influence on me. He said that the general relativity, which is part of some of what we've talked about, was the pinnacle not of just science, but of all of Western civilization. And so I agree. A lot had to go into that.

You had to have cooperation, language, there's a beauty, there's artistry, and there's also a hard technology. And the most important thing, which you keep emphasizing so rightfully is people. And the culture of an experiment is so important. And people who are really obsessed with what they're doing. Those are the ones you are looking for. That's right. Next question, the second to last question, is another quote from Sir Arthur C. Clark. and he said, when a distinguished but elderly scientist says that something is possible,

he is almost certainly right. But when he states something is impossible, he is probably wrong. So I want to ask you, Francis, what have you been wrong about, if anything? Oh, many, many things. In fact, let's go back to my career, career was half astro particle physics and half particle physics, right? I lived around accelerators. And when we were writing Halson and Martin, I actually gave Halzen and Martin originated

because I took a semester leave at the University of Hawaii because I was working with Sandhapakvasa. By the way, that was the time they were developing Dumont. And I had no idea what Dumont was, but I'm sure it's stuck in my brain somewhere. But at the time, they asked me to give a course, and they say, you just come and talk what you did the last week. I thought, I walked into the room, and the whole faculty showed up. Wow. And so I decided the set, the C-0 had just been discovered, a weak intermediate boson.

And I talked the first lecture about what a breakthrough this was. And so then I actually decided over the semester to develop, which we now recognize as the standard model as lectures. And so that was the beginning of Halden and Martin. So I think I never, there's something called the gym mechanism. and I couldn't believe that you could just invent another quark to fix a deep problem of the theory. And I thought that was incredibly naive.

And it turned out to be right. And I remember going through this history of me being wrong, not believing the gym mechanism. You know, the gym mechanism fixed a standard model was postulating that there was a charm quark in the theory. And so it made a big impression on me in the sense that, you know, sometimes you shouldn't hold it against simple ideas. The simpler an idea, the more elegant, this was in a sense elegant.

And my reaction was totally wrong that something simple cannot be right. nature. That simple. And so I learned a lot from that. It makes a big impression on me too because, you know, I, it doesn't feel good being totally wrong about something. No, absolutely not. But I think the mark of a good scientist is to recognize, learn from it.

And I learned my lesson from that. Absolutely. And I, you know, I never have, unless something can, it's demonstrate. trouble wrong. I accept everything, basically. I mean, if you, you have to have a very open mind when you approach a problem. It's not good to be biased. That's the thing I learned here. Yeah. Well, that really does dovetail into the last question, which is from Arthur C. Clark's third law, which states the only way of discovering the limits of the possible is to venture a little way into the impossible. And maybe I'll pivot because you've, you've said so much about, you know, kind of advice to your

former self. Maybe if you were getting into this career or any kind of career, you're 20 years old, you're at the University of Wisconsin-Madison, you're at UC San Diego or wherever, but what would you go into? What would you advise a young Francis Halzin to go and do, to do as you've done, to go into the impossible? I already gave the answer to that. You go what you're interested in, unless you're obsessed by the subject. I mean, being a physical, from all objective point of views is a miserable career. And I don't have to state the reasons. The only reason it's worse doing is you just enjoy this.

You're obsessed by it. You love what you're doing. And so if you do it as a job, it's going to be very, very disappointing, I think. So I think this is just, and the other thing, is, you know, I always lived with, don't underestimate yourself. I totally lived with until I went on this crazy adventure of Amanda and Ice Cube.

I always lived with the insecurity that I didn't belong to the circles I moved in, which I think must be true for almost every graduate student. Just get over that. And I don't know how to do this. I never did it until, you know, you go on a wild ride like we did with neutrino astronomy. Then you're just, you know, surfing the waves. Right. But at many times of my career, I think I missed opportunities because I was insecure.

And so, you know, it are not always the smart people who make the breakthroughs. It's another way. That's a very parochial way of thinking about it. You know, imagination can trump intelligence. There are many angles to doing research. And so just go for it. It's very, very wonderful that you say that, and we'll close with this. So when I interviewed Barry Barish two or three years ago now for this podcast,

I asked him that same kind of a question in the form. of have you ever experienced the imposter syndrome, which is this feeling of insecurity that you just spoke about? And he said, yes, I have it worse than ever now. What are you talking about? You have the Nobel Prize. He said, no, no, no, Brian. When you win a Nobel Prize, you have to go and sign this log book in Sweden that says that I got my Nobel Prize. So Barry's incredibly curious, very imaginative. And he goes back and he looks through the previous pages and he sees, he sees Feynman, and he sees a gal man at his home institution of Caltech. He goes farther back.

He sees Maria Gepard-Mayer maybe here at San Diego. And then he goes back to 1922 and sees Albert Einstein. He sees this guy's signature here, my favorite little sock puppet. And he says, I'm not worthy. I'm not as smart as Einstein. And I say, Barry, guess what? You know, Einstein had the imposter syndrome. You know, he wasn't always Einstein.

He said, what are you talking about? He said, Einstein felt that. that Newton did more for the human culture and civilization than any person before or since. And he said, wow, I didn't know that. I said, Barry, guess what? It gets better. Newton had the imposter syndrome. He's like, ah, you got to be kidding me.

I said, no, Barry. Isaac Newton wrote, he said, I live in shame that I never lived up to the ideals of Jesus Christ. So we all have our imposter, you know, kind of moments when we feel we're inadequate. And then he ended up writing. I don't know if you can read this, but I'll send you a copy of this book next time I'm out there. But Barry wrote the forward to my second book, which has his interview. And I hope someday that. I actually read it either on your webpage or somewhere.

Yes, yes. I don't think it's unusual. I think it's also, I don't think it's a problem. It's only a problem when it prevents you from doing things. That's right. That's exactly right. And I think you're right to have the courage. As you said, just as you said, just do it. Well, Francis, you've been an inspiration to me as a scientist, as a teacher, as a leader, as an author. And I'm just so glad and honored and thrilled that you were able to spend so much of your valuable time with us. Thank you so much. I hope we can see each other again. Maybe you'll come here in January and I'll go there in June and we'll go and get some cheese curds on the Capitol together. It was a pleasure. Well, wasn't that just amazing?

And it's such a delight to have guests like Francis on his curiosity, imagination, is purely, truly, truly contagious. I just get such a thrill talking to him. It's been 20 plus years since we were together. And so you guys give me the opportunity to talk to these people. And I just can't thank you enough for joining in. As I said, please leave a review of the podcast, a rating at least an asterism of five stars or so. Wherever you're listening to it, and you can leave a review on Apple Podcast. Don't forget to subscribe for my mailing list.

dot com slash list you could with one of these meteorites and one of them might have your name on it yes you driving while you're listening to this be careful watch out look out up ahead there could be a high energy neutrino coming your way and that's about it don't forget to subscribe to the youtube channel to see the slides from francis halzen and i'll give special thanks to my super producer stuptow and all the great support that i get at u.c san diego at arthur ccloc center of human imagination which i am privileged to associate direct it's kind of weird sounding but that's the truth So for now, I hope you have a rest of your week that is truly, truly magical. Until next time, signing off your fearful host, Dr. Brian Keating.

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