Into the Impossible With Brian Keating - EXCLUSIVE: Katherine Freese Has Evidence of Dark Stars! (#365)

Episode Date: November 8, 2023

Katherine Freese first presented the concept of dark stars at a conference in 2007. It was not well received at the time, as there was no evidence for it, and finding it seemed impossible. That is until recently… Katherine Freese is a renowned theoretical physicist, professor of physics at the University of Texas at Austin, and a member of the Simons Observatory. She works on a wide range of topics in theoretical cosmology and astroparticle physics, including her quest to identify the dark matter and dark energy that permeate the universe. She wrote The Cosmic Cocktail: Three Parts Dark Matter, published in June 2014 by Princeton University Press. She is one of the most renowned scientists that exists today, and I’m excited to have her back on the show to discuss Hubble tension, natural inflation, dark energy, and, of course, the star of the show (pun intended), dark stars! Tune in.  Key Takeaways:  Intro (00:00) In honor of Steven Weinberg (01:09) Katie’s take on Hubble tension (03:28) Natural inflation and the particle responsible for it (08:43) Katie’s take on dark energy (16:25) Philosophical and theological implications of Katie’s research (21:11) Katie’s philosophy as an educator (22:58) Katie presents her proof of dark stars (29:29) Pedagogical expectations (43:10) Outro (48:04) — Additional resources:  🥗 Thanks, HelloFresh! Go to HelloFresh.com/50impossible and use code 50impossible for 50% off plus 15% off the next 2 months. 📝 With a MasterClass annual membership, you can take one-on-one classes from the world’s best for $10 a month with your annual membership, get unlimited access to every class — and even better, right now, as an Into The Impossible listener, you can get 15% off when you go to MASTERCLASS.com/impossible. 🧑‍💻 Visit LinkedIn.com/IMPOSSIBLE to post your job for free! 📚 The Cosmic Cocktail: Three Parts Dark Matter by Katherine Freese: https://a.co/d/9r13mlp  💻 Check out my first interview with Katherine: https://www.youtube.com/watch?v=6Hp0lBRf7WQ  ✖️ Katherine’s Twitter: https://twitter.com/ktfreese  ➡️ Follow me on your fav platforms: ✖️ Twitter: https://twitter.com/DrBrianKeating  🔔 YouTube: https://www.youtube.com/DrBrianKeating?sub_confirmation=1  📝 Join my mailing list: https://briankeating.com/mailing_list  ✍️ Check out my blog: https://briankeating.com/blog.php  🎙️ Follow my podcast: https://briankeating.com/podcast  — Into the Impossible with Brian Keating is a podcast dedicated to all those who want to explore the universe within and beyond the known. Make sure to follow so you never miss an episode! Learn more about your ad choices. Visit megaphone.fm/adchoices

Katie Freeze is a renowned theoretical physicist, a professor of physics at the University of Texas at Austin, and a member of the Simon's Observatory. She's one of the most acclaimed scientist of our time, and she's recently made headlines again, claiming to have found the first evidence of dark stars, putting us one step closer to figuring out what the universe is made of. Join us for a sip of Katie's intoxicating cosmic cocktail. Any sufficiently advanced technology is indistinguishable from magic. Open the pod bay doors, hell. Cosmetology meets cosmology. Today's a special episode for me.

It's not all the time I get to interview not only one of my friends, not only one of my collaborators, but one of the most renowned scientists that exist today. And that's Professor Katie Freeze of the University of Texas at Austin. Welcome, Katie. How are you enjoying San Diego? Thank you, Brian. I'm having a great time. It's always great to see you. It's great to have you back for your second appearance on the podcast. The first time you're on was for this just amazing book. I mean, there are too many books that, you know, I read cover to cover in science because a lot of it, I mean, you and I are experts in science, so we don't really need to know much of these scientific content.

But this was so much fun. I read the whole thing and I really devoured it and digested it and we're going to get into the hijinks of it, maybe as a recap for people that haven't seen in, I might re-released or linked to the episode when Katie was on two years ago. It's amazing. But it's pertinent today. We have now Simon's Observatory branded merch, which you can get for $100 million or so. This is a bottle of whiskey for your next, for your next cosmic cocktail, Katie. That's hard to say.

And since you were last on, a lot has happened to the Simon's Observatory. and for your in your career. And we're going to talk about all that, including this mesmerizing, mystifying concept called Dark Stars, which may have been detected. We'll talk about that with this device that's up front right there,

the James Webb Space Telescope. Oh, there it is. My student 3D printed it. But first, let's start with big news, sad news in a way. About a year and a half ago, you tried to connect me with Professor Stephen Weinberg, and since then he passed away.

He actually gave a lecture of the same kind of honorary lecture that you're giving here. Dashian Memorial. He did it remotely because it was near the end of his life. But you're here in person very much alive. Talk to us briefly about Stephen. What did he mean to you? What is it like being the director of the Weinberg Institute? Is the Weinberg Institute?

Or what do we call it? It is. Yes, it's the Weinberg Institute for Theoretical Physics. And it is in honor of Steve Weinberg, who was the greatest physicist of our time. There's just no question. I think pretty much everybody agrees. So he was the theorist behind much of the standard model of particle physics, the quarks and leptons,

and how they merged together, especially going to higher energies and back in the early universe, the forces of nature unified together, the ElectroWeak theory. And can I also say he was a friend. Yeah. One of the kindest people on this planet. He was wonderful.

He was, as I say, a mensch. He was one of the few nobles. that I have not, didn't get a chance to interview, sadly, we'll never get to. I had his co-loriates, Shelley Glashow on, and they were basically in a friendly competition since they were in high school together. It's just amazing. That's right. All the way up to Cornell and Harvard and their careers were so intimately intermashed. And Shelley, thank God, is still very much alive and with us and sharp as attack. But I wonder, you know, what Stephen might make of, you know, so the discoveries that have happened just in the last couple of years.

And in particular, things that we are partnering on with the Simon's Observatory to try to uncover you from a theoretical angle and myself and my team from experimental angle and then kind of commishing them together. So is it not the case that we know now that we know less about certain things in the universe, including dark matter and especially this Hubble tension? I've been just dying to ask you about that. So where do you come down in the Hubble tension? What's the answer? Because I look to you for the most erudite advice on these matters.

So, Katie, tell us, what is your take on the Hubble tension? Is it for real? Should we just ignore it? Is it a fad? What do you make of it? Well, I think it's really important. So the trying to learn about the expansion rate of the universe from data from the cosmic microwave background, which comes pretty early in the history of the universe, or from supernovae that are more recent. and it seems that these numbers are discrepant at 5 sigma at this point. So the Hubble constant, based on this earlier epic, is lower than the Hubble constant, 67 versus 72. Now, putting it in a broader historical perspective, when I was in grad school, there was the camp that said, it's 50.

And the other camp that said, it's 100. And so now we're arguing about 67 versus 72. So is it possible that there's something going on in the experimental observational side? that will resolve and everything will meet. I don't know. Wendy Friedman seems to think so. I don't know. Is it an observational problem?

In the meantime, as theorists, we get to have fun trying to explain this. When I think about Katie Freeze, I think about your taste and you have exceptional judgment and taste, and you're always seeming to be, you know, where the puck is going. I had Adam Reese in that very chair about five months ago when he gave a distinguished lecture much of the kind that we're looking forward to you're giving later on today. And, you know, there's a notion that, you know, maybe there are a thousand flowers that can bloom theoretically. But from an observer's point of view, they seem to get really entrenched in different explanations. And I spoke to your, you know, a friend of Mike Turner recently.

The episode hasn't aired yet, but by the time this one does, it might. And we talked about, well, what are the known knowns about things like the Hubble tension? So not exotic, things like magnetic fields. We know magnetic fields exist. Do you have a favorite explanation? or is that kind of a non-scientific way to think about it? Like, should we have favorite explanations? Should we be married to our ideas about theoretical models that could explain it?

Or should we just be open and, you know, kind of see what happens? So I always, my attitude is always we should be open to see what happens. But there's a lot of ideas that fail. They get ruled out. And so then you move on. And the question is, did some, is if you're going to introduce new physics, would it be before the time of the cosmic microwave background? Would it be after the time of the cosmic microwave background? And I think everybody agrees that the later stuff is much harder to work

with. And so I thought particularly interesting, I think, is the idea of early dark energy, where you would have a vacuum component to the universe that it never dominates, but it's important just before the production of the cosmic microwave background. And it would come in as a constant vacuum which suddenly disappears at exactly the right time. And I'll tell you, I saw that. And I thought, oh, my God, that looks like a phase transition to me. Yes. So we've been looking at first order phase transitions as possible explanations.

And that would be where you make bubbles of the new phase, kind of like boiling water. And so this is, yeah, it's a possibility that that would be an explanation. We called this one the chain early dark energy. And yeah, so that got us interested more generally in bubble collisions and how they might actually show up in the gravity. The bubble collisions lead to gravitational waves that you could see. So there's a prediction there. And how would they agree or be in tension or compete with the primordial B mode polarization that we're looking at the waves of gravity that generate those phenomena? No, they not in the same frequency range, not showing up in the same way.

Could you see them with like LIGO? Yes, you could see them with things like LIGO. Or if they're different, not the ones for early dark energy, but more generally, you could nanograph has stochastic gravitational waves that they've just recently confirmed. That's right. And is that due to supermassive black holes colliding? We don't know. Or actually what might fit the data better would be bubble collisions from first order.

phase transitions in the universe. And so we're exploring that possibility. It's peak pollination season, and my business is scaling fast. To keep the nectar flowing, I need a phone plan with top priority data speeds. That's why I chose GoogleFi Wireless. My connections stay strong even when the hive is buzzing. Plus, unlimited plans started $35 a month. Now, that's a deal that doesn't stay.

Explore GoogleFi Wireless plans today. Plus taxes and government fees. Google Fiore Wiarless is not subject. to data traffic deprioritization during times of high network usage. When I first saw, you know, kind of the initial data from Bicep back in 2014, 2013, when we started to have an inkling that we were on to something, it never really occurred to me the kind of uproar that it would stir up. And, of course, I wrote about that in my first book, losing the Nobel Prize.

So have I talked to you about the what the uproar it did to me? I want to talk because I remember we did I did get an email from you and I did see things like that around the time when the rumors were kind of percolating along with many of my friends and colleagues. So tell me about the upward. I actually haven't I haven't heard this from from the direct party involved. So please tell us, kid. We have a model called natural inflation. Yes. It uses a particle and axiom as the particle that's responsible for inflation. And the idea of using axions for inflation, I thought it was a great idea back then. because how else are you going to explain this bizarre situation where you have in, it's a really good idea. And since then, it has been picked up by lots and lots of people, different variants of it. The original variant, well, we had very specific predictions for what it would look like in CMB data. And when this original short-lived discovery happened, it was a perfect match to the CR theory. So I went through the roof and I, we all at, at Michigan, I was the University of Michigan. and we all got together in a giant room to talk about what the new discoveries are.

And I was like going, yay. But the basic idea still holds up, even though not that original simple version. Explain for the audience that may know, I mean, I have the most brilliant audience in the known universe, I always say, but explain for my audience that may not be familiar. What is an axon? And what does it have, if anything, to do with inflation rather than being a putative mechanism for dark matter? That's where they've heard about it primarily on this channel.

So what is an axiom and how can it be related to inflation at all? The original axiom was the brainchild of Stephen Weinberg and simultaneously of Frank Wilczek, both Nobel laureates. Frank's been against. And though that idea would be a particle that would solve problems in the theory of strong interactions. And so that is the dark matter candidate that people are very excited about and looking for. However, the word axion, I'm going to put quotation marks around it now, is used more generally for anything that has similar physics built into it.

So what we need for inflation in particular is we need, this is a potential for the vacuum energy, which has, it's a very, very flat potential. And so it needs to be very wide, but then it needs to be short. You have to have lots and lots of e-foldings of inflation. The universe has to inflate for a long time. but inflation also produces density perturbations, which we see in the CMB, and you can't overproduce those. That's right. So the beauty of the axiom is that there's a reason for two different scales in the problem.

Most particle theory, you only have one, and so the height and width would be the same. But if we use an quote-unquote axiom, modeled after the physics of the QCD axion, we have a really good, literally natural candidate for inflation. So that's what our basic idea is. It'd be higher energy scales, important earlier in the universe. But it's the same on the theoretical grounds. We're writing down the same things. I see. Now, I don't have a really strong opinion about the following quote,

but I've heard it said, I'd love your reaction to it. A theorist only has to be correct once in her life to make a career, you know, outstanding career. An experimentalist only has to be wrong once in his or her life to ruin his career. Now, I'm probably a counter example to that. What do you make of that? Do theorists, you know, have a propensity to kind of swing for the fences and, and if something sticks, then so be it. But there's sort of what I call lack of quality control, an overabundance of theory. Or do you think it's really more on a parity that actually both experimentalists and theorists both have to grapple with quality and quantity and equal measures? What's your take on that silly quote? Well, let me start talking about on the theory side because something I know more about. We have to. Yeah, whatever we do, we can be creative, and that's what I really enjoy doing, sitting around the table, batting ideas around with people, and then you have a flash of insight.

Wow, we've got to try this. It has to be consistent, it has to be self-consistent mathematically. It has to be consistent with all the data that are out there. And if you violate any one of those things, and you, so if you make a big mistake and you put that out in public, you could really hurt your career too, just in the way you said an experimentalist could. So that's not something I've ever done. I think I'm known for having a lot of ideas. And I'm very careful. Most of them die within 10 minutes or maybe within a week. But having them stick around for 30 years, that's pretty cool. And I guess I remember in grad school, one of my professors saying,

if you have a paper that's still quoted 10 years later, you're doing well. And so I guess that's the standard that I live by, and so I'm doing pretty well. one of my favorite things about how you operate, shall we say, or the things that really speak to me about your brand, the KD. Freeze, Catherine Freeze brand, is that you love working with experimentalists. And in fact, without you, the Simon's Observatory may not have, you know, gotten to the level that it's at because you've been an instrumental,

no pun intended, supporter intellectually and logistically, financially, et cetera, et cetera. How do you choose of all the things that you're portals? portfolio could allow as you're, I mean, you've had some just outstanding, you know, successes in your career that have led to tremendous leadership opportunities for you. How do you choose, as a leader, where are you going to put your institutions' finances and the most precious resource, their intellectual capital and attention? How do you allocate that as a leader? Well, thank you for the compliment. And I have always looked for physics that you can test. And I mean in my lifetime, not 300 years from now.

Yeah. So I work on dark matter that you can test, that is being tested. We're behind some of the tests that are going on now. Yeah. And also on inflation, when we realized you can test this, that which is very, not just the idea of inflation overall, but individual models are testable because of the density of your perturbations, because of these primordial B modes,

that Simon's Observatory is really really, going, gunning for. And that is frankly why I got all excited about C&B experiments because I thought, we're going to get the B modes. We're going to prove that natural inflation is right. I was all into it. And so then the, then the funny thing is, you know, there's another piece of physics that I also have my very first paper ever, the bounds on neutrinos from cosmology. So the idea that you can go after neutrino mass with cosmology. And all of a sudden, I was writing, I was writing, I, I hired a postdoc. Martina Jurbino.

She's also a leader in Simon's Observatory now. And we were writing a bunch of theory papers and comparing to data and da-da-da-da-da. Guess who can go after that? Simon's Observatory. So when, I know. We can go after dark matter. We can go after so much. Planet 9.

Yeah. So that was from, that's why I really wanted to get involved and started hiring postdocs, students, lots of people. And most recently at UT. Your former postdoc, Nikolitsky, is doing great at Texas. A picture of him here, yeah, good old Nikolitsky. I gave him a shout on on Joe Rogan when I was on it. I think I gave you a shout.

I'm going to get you connected to Joe Rogan. And hopefully Lex Friedman, both of whom I've become friendly with. Let's turn to this, back to this book. In addition to such cool topics as a DNA dark matter detector, with you and the president of the Simons Foundation, I believe David Spurgel worked on many, many a year ago. the aspects for detecting dark matter, as you say, not only in your lifetime, but in your, in your careers, you know, kind of golden years that we're, you know, I don't say golden years,

but just most productive years. When you're making hay, so to speak, while the sun is shining. Hello, students of the impossible. It's Professor Brian Keating here with just a tiny little homework assignment to interrupt your podcast. And that's to make sure that you're subscribed to the podcast or following us. your podcast app of choice, get some research, and actually only about 50% of you are actually following or subscribing to the Into the Impossible podcast. And really mean a lot if you could

subscribe and keep up to date with me and with all the greatest content. I'm putting out tremendous amounts. Podcast has grown in popularity, but it can be better and bigger with your help. Do that. Please do it now. Don't wait. You'll forget. If you're looking to really boost your position on the grade curve for some extra credit, make sure to leave a rating or review of the It really helps. Thanks a lot. Now back to the show. I came away a little bit pessimistic. I mean, the subtitle is, you know, three parts, dark matter. I came away a little bit pessimistic from this book when I read it. And I've revisited it recently. Let me move the CMB beach ball. So people can see it. That, you know, perhaps it's just it's a long shot, but at least it's not as big a long shot as dark energy. You know, when I sat here when Adam Reese and I were sitting there, it just seems like. there's almost no hope for dark energy coined by, as I said, Mike Turner, who you'll see that episode soon. But even Mike seems to agree that like we know almost nothing about dark energy. And where do you stand? I mean, we're going to get into dark matter, dark stars, etc.

What is dark, the other parts of the cosmic cocktail? What's your, what do you make it? What the heck is going on? Who ordered that drink? Dark energy. What the heck? Yeah. So 95% of the universe is the dark side. And 70% is the dark energy. And at this point, you might as well call it gobbledygook because we know so little. And it's, yeah, well, I will tell you a story of my involvement. So I remember when people started the idea of dark energy was named dark energy all of a sudden. And then all of a sudden it's going to be parameterized in terms of the equation of state W. And I'm sitting there thinking, whoa, wait a minute.

The observers are going to specifically look for this one thing. But how do you know that's the right way to parameterize it? So I was at a meeting in Chicago, I was out in the halls, all of a sudden I had this inspiration. Wait a minute. What if you don't need any dark energy at all? What if it's only dark matter and, sorry, only matter and photons and so on. So that's all there is. There's matter.

There's photons and there's nothing else. But the equations change. The equations are different. And I'd been working with a postdoc Dan Chung on extra dimensions. So there could be, in addition. to our universe, our three-dimensional universe, sitting as a membrane in many other dimensions, and there could be another three-dimensional membrane somewhere else, and the effects of this extra-dimensional stuff is to change the equations governing the evolution of our universe.

So Einstein's equations, as applied to our universe, the Freeman Robertson-Walker equations, there would be an additional term, okay? And so we had thrown around, well, you don't know what that term is, but what if it's such that it only becomes important recently in the history of the universe, it causes acceleration just with matter and radiation photons and so on. No dark energy. So I had that idea, and I probably foolishly called it Cardassian cosmology. So I still think that could be true. It's Einstein's equations that need a... Since that time, that was 2002. So then since that time, a lot of people have played around with a lot more sophisticated modifications of Einstein's equations, disformal gravity, galileons, da-da-da-da-da-da. Most of those ideas have been ruled out because gravitons that move at the same speed as light pretty much.

So those ideas have mostly died. So that I still think is an interesting direction, but I kind of stopped working on dark energy. It's too hard. Yeah. 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. It seems just hopeless. Too hard. The more, as your colleague, late-grade colleague, used to say, the more, you know, we learn about dark energy, to paraphrase him, he said about the universe, but he said, the more we learn about the universe, the more pointless, it seems. The more we learn about dark energy, it seems mostly pointless. Do you ever think about the philosophical or theological even implications of your research? Sure.

I think most of us in cosmology thought about it as part of why we do what we do. now the hmm well there's the question is there God or is or is or is there not and how do we I think cosmologists some are automatically atheists

no we're just doing we're doing laws of physics we're right now in equations and that's all there is others are very religious and well that tells you something that you could this entire spectrum is possible and still be doing cosmology and so where do

I stand on this? I'm not sure. And how does it, you know, there's some questions like, what is the origin of time? Does that have something to do? Is that a physics question? Is that a metaphysical question? I, in my heart, I believe all these things are physics questions and that we'll get somewhere with them. And similar to the multiverse. What are your thoughts there? Not crazy about it. I feel like it's chickening out. It's not chickening out, but you're not answering the questions that you're supposed to be answering, which is why does the fundamental constants have the value they do? Then, yeah, yeah, I know, if you change the value of E, the electric constant, by one tiny, tiny bit, then we all

disappear because our nuclei don't hold together. That's right. Yeah, well, that doesn't mean that we happen to live in somewhere in a multiverse that has the right value. I don't buy that, I'm sorry. I want to know why it has the value it does. That's right. Yeah, and I think these are kind of the questions that plague, that should plague people.

I find oftentimes my students don't think about these things, that they got into cosmology because they're really good at, you know, building instrumentation, working on dilution refrigerators and vacuum systems, or they got into because they're really good in theory and calculating and they love doing homework problems as an undergraduate and this got them into it and they're creative and they want to think about things. But they tend not to really address the, you know, as Roger Penrose calls it, the mastodon in the room, which is, you know, what the heck is going on with the origin of the universe? On the other hand, though, Katie, I wonder how you react to this. If I study, you know, my biology colleagues, you know, that gave me this brain and everything else, like their job as biologist is not to explain like the origin of the origin. of life, right? I mean, some work on that, but that's not their job. So why as cosmologists do we think about understanding the origin of the universe? Maybe that's a cop-out. I don't know if you

want to react to that. If not, we can move on. But yeah, I just, it's important to think about the big picture topics. Maybe I'll segue into another direction briefly. And that has to do with you as an educator. You know, you're not only, you know, this world famous theoretical physicist, you know, contributing for, in so many different fields from machos, dark matter. Today I learned about axioms and inflation. But you're also an educator. And I think of you like that. And I've learned a lot from you, not just from your wonderful popular works and books and

appearances and so forth, but also from your papers and seeing you lecture as we're going to be treated to later today. What's your philosophy as an educator? Who do you look to? Do you have role models, mentors? How does someone become a teacher of the, caliber that you exhibit? I feel like as I teach, as I get more and more experience, I relate to students better and better. And I even teach classes of non-sum. Right now I'm teaching a class

to non-scientists. Really? And it's maybe the only class they're going to take in anything related to physics or even the hard sciences sometimes. And it's my job to get them excited. That's, I think, the main task I feel in this particular case. And I've learned that if I tell stories, personal stories or stories about Tycho Brahe or whatever, that they have a lot of fun. Galileo. Oh, there's Galileo. Okay. So you tell stories about people and you bring it down to earth and they really have fun and they engage and who knows which one of these is going to become a politician who votes on whether we get funding or not. So I feel like that's one of my tasks, my jobs. And I also, I've always thought it was my job to mentor young women. So I've always

made a lot of effort there. Initially, it was really assistant professors around the country who would call me, that we would talk and I would advise them on, you know, when you have a job interview, he's what you should expect or whatever. And so I've always taken that very seriously. I think that's part of my teaching role. Yeah. And I have, I had an undergraduate who I thought, I think She's outstanding. So I told her, hey, why aren't you applying to grad school? Oh, I hadn't thought of that. And so now she is, you know.

Was it Jan 11, you're on your show? Jan 11 was my very first graduate student. Past guest, yeah. Yeah, she's pretty awesome. Phenomenal. Yep, phenomenal. She is. Love Jana.

And she also exemplifies that trade of doing, giving back to the public as well as to your colleagues and into your career and what you do. Well, that's another aspect of his not teaching, but outreach. Yeah. So I think that's a really important thing that we have to do. And so I give lots of public. lectures, TV, radio, panels, and I think, podcasts. So I think all of this is really important for us as scientists to reach out to people who

want to know what we're doing. Yeah. And I'd pay our salary. I always joke, you know, if you worked at a paperclip making factory and your boss came in and said, yeah, what are you doing today, Brian? It's very, very complicated. It's very arcane. And that's strapped.

You can't understand it, boss, man. So just leave it to the expert. You know, they would be fired. next day and yet we expect the public to just keep shoveling money towards us because we're so smart and and sometimes i do get this this comment and i've gotten a lot of heat from this on on twitter and other places where you should follow katie also katie frees on twitter but the uh the notion i said that you know it's it basically should be part of our education public communication outreach yeah oh yeah and i always hear oh no scientists sabina

hassenfelder many-time guests no scientists should just work on what they do and we need people to do. And I said, oh, so if you, you know, if you want to continue to do what you do, you have to at least give some ROI return investment to the public that pays your salary. Otherwise, you know, it's not only jeopardizing you specifically, but the notion of scientific education among the public. And she said, oh, it's too hard. Well, okay, you know what's hard? Also, quantum electrodynamics is really hard. Working on inflationary potential is really hard. You weren't born knowing that. You learned how to do it. So anything you feel important, you should learn, including communication.

I'm not saying everyone should be Mealdegrass Tyson or KV Freeze, but everybody should have at least some exposure to the so-called soft skills. Anyway, I'll give you a reaction. So when I actually advocated for a course where, I mean, if you think about it, this is something that's not taught. So you're supposed to go out into the world and you're going to be judged immediately on how well do you communicate, which you do. And you get no training?

No training? I think that's insane. So I actually did create a course where people would give talks at different level. and I brought in speaking, speaker speaking experts. I brought in breathing experts because all of this matters. Can I take this course? Yeah, isn't that great? And I created a syllabus that actually went around the country and other people used it.

But you know, in the end then you're told, well, this isn't really hardcore and we really need you to teach something more, you know, substantive. Rigorous, right. More rigorous, yeah. So that course kind of died, but I think it's, I'm really believing it. That's what Janet told me too. She said, you know, when she was writing her first book, they were like, don't do it. You're not going to get a job. She wouldn't even have her job at Barnard. But then her second book or something, they said, well, we're not going to, you can write it.

We won't punish you for it. That's ridiculous. I had the same thing. I had a Nobel laureate, the son of a Nobel laureate who is no longer here. So I can speak about him. I love him. He loves me. But he used to say things like, you know, we won't, we won't hold it against you, but we're not going to give you any sabbatical time.

We're not going to do anything for any of my books. And so I've done it, you know, in my summer, you know, when I'm not getting paid by the university. So that's when I. Yeah, I'm asked, would you like to write another. book and I'm like, when am I supposed to do that? I mean, it's tough. 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 invalid May 14th or May 27th, U.S. only exclusions. apply see homedepot.com slash price match for details. Yeah, especially with all the stuff that you're juggling there. Let's get to that really exciting stuff that just, you know, as soon as I heard it, I didn't even have to look. They said that Leibniz once got a paper and he was asked to review. It was

about calculus or something. And the author was anonymous and he said, it's Isaac Newton. They said, how do you know? And he said, I know the lion by his paw. So I knew the lioness. you know, when I saw the, you know, the Dark Stars, when I saw JDSC, first of all, talk about this. This is my brief that I got from one of my sponsors, Ground News. Dark Stars are a proposed concept in which the first phase of stellar evolution in the universe is powered by dark matter heating instead of nuclear fusion. And then I read the PN, proceeding the National Academy of Science paper, which is a one, not only does Katie, you know, do the hardcore stuff, but your writing is phenomenal.

And did you do like, well, let's get into that later. I don't want to keep, you know, keep just to sing your praise. I'll be here all day. But talk about dark stars are formed at the centers of proto galaxies and the sufficient abundance of dark matter servers or heat search. Where do these things come from? Are they just like, let's fit the data or like, have you been thinking about these for a long time? All right.

2007. Wow. I was a Miller professor at Berkeley as a visitor. And Doug Spoliar, former Michigan undergrad, had started grad school in Santa Cruz and said, I want to do a project with Katie Freeze on something to do with dark matter. And after many iterations of throwing the ideas in the garbage because we were so frustrated. Well, something good came of it. And we involved Palo Gondolo as well.

And so the idea that the very first stars that form 200 million years after the Big Bang inside these proto-galaxies that will later merge together to make galaxies. And what happens is you have, at that point, the only thing existing is hydrogen and helium from the Big Bang. You don't have any other elements around yet. So that clouds of hydrogen start to collapse inside the space. very centers of these proto-galaxies. There's molecular hydrogen. There's molecular hydrogen. Yes.

These clouds collapse, start to collapse. And in the standard picture, they get to be really, really tiny, and then fusion kicks in and so on and so forth. And we just ask a simple question, yeah, but at the center of proto-galaxies, there's a lot of dark matter. What does that do? And the answer is that the dark matter, let's say it's some type of dark matter that annihilates these particles annihilate among themselves, such as weakly and interactive.

massive particles or some types of self-interacting dark matter. So if the dark matter annihilates, the annihilation products, they collide with the hydrogen and they get stuck inside this collapsing cloud. So all of a sudden you're dumping all the energy that was in the dark matter and you're dumping it into the cloud as a heat source. So we realized, okay, well that's going to stop that cloud from collapsing. And then a year later we realized, oh my god, it's an actual star. It really satisfies the four equations of stellar structure.

It's in hydostatic equilibrium where gravity is balanced by the pressure all because we have this dark matter heating going on and so forth. And they become, well, they initially start out about the mass of the sun. But how weird. They're 10 AU in size. 10 times the distance between the earth and the sun. Big, puffy, cold. There's no fusion.

There's not hot anywhere. Dark matter annihilation doesn't care how hot it is. And that means that more mass can fall onto them. So they grow and grow and grow and grow And they can grow to become a million times as massive as the sun And a billion times as bright It's just I'm telling you it took us a couple of years To put all these pieces together

And at this point John Mather The Nobel laureate who put Two-time guest on the podcast Creator of the James Web Space Telescope And John Gardner PI of one of the instruments They say to us come on this is a cool idea Tell us what we're going to see What shall we look for

And that was 2010 and so we migrate student at the time Cosmin Ily he did it he figured out okay what are these spectra what are these things going to look like and guessing how many there could be that's hard but so we went so we were waiting for the data from the JWST and when it came out we knew exactly what to do with it because we were we had planned on this you know so when the data came out recently announced there was a you know claim that there were two galaxies potentially that that might harbor these objects. 10 AU sounds big, but, you know, a redshift of 11, it's infinitesimal, least small. So how can you, you know, how can you be sure? How could one verify or refute that these are,

these galaxies themselves harbor these massive dark stars within it? Well, one dark star would be as bright as an entire galaxy containing a bunch, lots of smaller stars. And the way to tell the difference will be, well, let me, you know, let me back up. Yeah. JST has 700 objects from, potentially from the early universe, probably, but you're not really sure until you get spectra, the brightness at different frequencies. And so they had, at the time we wrote our paper, they may have more now, but there were nine with spectra that were absolutely confirmed as being early universe objects. And of those nine, five were had publicly available data. And so we looked at those. and four in particular interesting, the jades objects,

James Webb Extragalactic, I don't know, survey. GSZ11-0, that's such a beautiful name. These are, so of those four objects that had spectra, three of them are consistent with being dark stars. And what I mean by that, so the spectra, spectrum of any star, it's a black body. It goes up and it goes back down in a very well-defined way. And our stars would be made only of hydrogen and helium.

So that's all you would see information about. That's all that you would see. Whereas these competing galaxies, they have also later generations of stars in there. So you would see that's processed. So you'd see carbon, nitrogen, I don't know, neon, whatever. And so down the road, when we get clean spectra, then we'll know which it is. How can you differentiate? So I would imagine these could be confused with other objects that are also, to my knowledge,

not discovered, but are part of the panoply of research portfolio for web, which is called Population 3. Am I right that we have never discovered something that we know for sure is population three? And then two, how would you distinguish a dark star from a population three object? So the population three objects were the, when I was telling this picture of the collapsing hydrogen clouds, that is the standard formation of the population three stars. And they are hot.

They have fusion. So they can't grow very large. They can grow about to 500 times as massive as the sun. We're talking about a million times as massive. So our guys are a hell of a lot brighter. Right. I see. So that would be a way to distinguish it.

In fact, the only way that we're really going to figure out what's going on is probably not the current objects, but many. I mean, James Webb is just getting started. And so there will be many more objects coming in. And some of those will be magnified by lensing. In other words, they'll look brighter and you'll have more information because there's stuff in front of them that makes that amplifies the signal. If you have just an ordinary like Lyman Alpha cloud or just some primordial hydrogen cloud, molecular hydrogen cloud or other configuration, can you still form these Darkstar? Like could there be some forming in the Milky Way or somewhere or they only form the primordial universe? They're as soon as you get other chemistry going, it's different.

So we're talking about hydrogen and helium only. Only, right. So you couldn't do it from pre-processed. Well, I mean, no, not. You can't do it from processed stuff. But what if there's some void that hasn't had any action? That's right. And so maybe somewhere in there, there's still sitting, there's still a few forming in there.

But. So we wouldn't expect to see one floating by in the Milky Way or something. Right. I see. No, too bad. So, yeah. So these objects are, you know, really captivated the attention in the media along with. Reuters picked it up.

Reuters new scientists. Once Reuters picks it up, everybody. picks it up, Scientific American. Yeah, front page article in New South. It was incredible. Yeah, it's beautiful. We'll show a cover, the cover article of it on the B-roll footage if you're watching on YouTube, where you can find me, Dr. Brian Keating, but also find Katie on Twitter and many other interviews that I've done with her and she's been featured before. So I want to talk about another thing that might be concomitant with this discovery. And this is the so-called claim that is proffered about the same media in some circumstances.

unfortunately, new scientists or fizz.org, you know, either the Big Bang never happened. Oh, I think I know it was coming yet. Or the universe is 26 billion years old, not 13 billion years old, including by a gentleman Rajesh Gupta, who's a Regenda Gupta, who's in Ottawa, who's I've been in contact with, but maybe he'll come on the podcast and come to visit us. But anyway, tell us, what is this connection? What do you make of these claims? Because I'm old enough to remember in 1996 or whatever when Hubble Deepfield came out and you heard the same kinds of things. These galaxies are too mature to have spiraling arms and so forth and have this grand design. The universe must be much older. In fact, it must be infinitely old or eternal.

What do you make of these claims? Why are they so eye-catching and click-baity for the media? Well, I mean, sure, it would be exciting if we'd been getting everything wrong all along, but you know what? I don't think we have. Brian, I'll turn to you. You're the CMB guy. You tell me, what's the age of the universe? This is my podcast. Every piece of data you've ever looked at. Right. Well, so the claims are the following.

So you have to, in my mind, a part of education is you should be able to steal man or steal woman the opponent. So they'll say there are other explanations for the CMB. There are things that we don't understand in the CMB that need to be explained and including like how do these perturbations get there? How do these, how do it get to be so thermal? Yeah. And then other things can be explained by phenomena, as I said, that are. more well formed, like plasmas are much more familiar than, say, inflation, or scalar field that we only know one example of the Higgs boson.

Again, I'm just bolstering my opponent's viewpoint, right? So they'll say there are these props. And they'll say that, you know, light can lose energy. It can become redshifted and it can make the appearance of all these things. But the worst thing is that these galaxy size tests fail the standard expansionary hypothesis. They're inconsistent. The Tullman test, they fail these are called Toulman tests. And the only way around those Tolman tests that the galaxy size doesn't decrease with distance,

according to these people, is that, you know, the universe is much, much older and then we see it. And so the light has gotten tired by its travel, some mechanism they don't explain. And or the fundamental constants are changing, as you said, you know, alpha is changing, what have you. Or, you know, or some hybrid. So anyway, obviously the CMB tells us a lot. It doesn't tell us about time equals zero. It only tells us, only tells us 380,000 years after the Big Bang. But there are lacunae in the Big Bang model.

That's the nature of science. So what these people attempt to do is say these flaws lead to a consideration that maybe the Big Bang is wrong. Okay. That being said, what could or could not these dark stars do to alleviate these hypothetical tensions between the age problem? I had Allison Kirkpatrick on from Kansas. She was the one who's quoted like, astronomers are panicking, you know, because the web shows spiral galaxies. So that is a concern. I have my own take on that. The C&B is dispositive, in my opinion, but that the Big Bang happened. But these galaxy formation models, they seem to require

some maturation beyond the 13.8 or beyond 300 million years after the formation of the light elements. So tell us, you're the expert in these things. So how could dark stars alleviate or not this problem, quote unquote, of mature early galaxies? So another way to talk about, so the standard model of a cosmology, the 70% dark energy, da-da-da-da, the Lambda CDM model of cosmology. Three parts. People, yeah, three parts, dark matter. People have done simulations of structure formation.

And you have certain predictions for how many objects you should see you have, and so forth. And so these bloated things that they're seeing early on where this, there's all those, what faction of the bare hands of the universe have to go in to create one of these things? I have two answers to that. one is, well, we're very happy if some of those are actually dark stars. So let's take away some of the big beasts that you don't know how to explain, well, we do. So that is, I was actually thinking of mentioning that. And actually, secondly, there's also the Eddington bias, and I don't know what role that plays

in this. This is an observational bias. Okay. If you have, there are, let's say, lots more faint objects than bright ones, then it's more likely that a that a faint one looks bright than the other way around so in terms of basins it's not a flat prior there's a you need to take that into account I'm not sure so people have some people have done that with with these with these galaxies so that could be part of the explanation but I'm I'm sticking I'm sticking to my guns I want some of them to be dark stars that would be

phenomenal we'll take some and will be the podcast that had you on when I want to close out because we have to get you over to the medical school to give your colloquium that is so desirable for millions of people to go watch and maybe eventually we'll get a recording of it. Brian, can we have a sip of this before we do anything else? Absolutely. Let's get these Irish up these coffees. I want to ask you just two last questions. One is about your pedagogical expectations. So I have a rule for my students, including one you're going to meet in a minute, as he escorts you to get your laptop. And that is that my experimentalist, they need to know theory.

They don't need to do theory. They need to know theory. They need to know it as well as an incoming theoretical physics graduate student. Yeah. Sounds good. Not required to do it. And then obviously they have to be world expert in the experimental aspects of the polar bear, Simons is there a?

Simons is aervatory. They need to know that way better than I do because they're interacting with it. You know, I already have my PhD. They don't, right? What? And I call that the experimental minimum in deference to our good friend Lenny Suskin, who talks about the theoretical minimum. He means something else by it.

But I want to ask you, what is the theoretical minimum? Like you have a new, fresh off the boat grad student. She's coming to Texas. She's working with you. What does she need to know about experiments, if anything? Oh, oh, about experiments. I thought you were going to say what courses does she need to take, which is- I assume that that's relative to-

All right, let's assume everybody's taking the same courses, including quantum field theory and graduate cosmology and so on. Which you took as a high school student. No, no. Didn't you start college at like 15 or 16? Partly because my high school had no physics at all. So it was the other way around. But anyway, I survived it.

So I talk to experimentalists all the time. It's part of your brand. Oh, you have to. You have to. So they have to. Yes, I make them do that. How do you instantiate that? How do you make them do it?

Well, for one thing, we have in our Weinberg's seminars, we have experimentalists talk to us. And so that I think is really helpful. And who did we hire recently at UT Austin? We can't just... We have to hire experimentalists. So we hire your former postdoc Nikoliski at UT Austin. And we all go to Weinberg lunches together every Tuesday.

And we talk to each other. So that's, I think, really, really important. So that's synergy. And we have the astronomy department in the same building. you take the, all in the same elevator, and so we talk to astronomers up there as well. We also talk to, we have dark matter experimentalists. We have to talk to each other. Yeah, that's phenomenal.

Last question has become kind of a boilerplate question that I've asked people, change them since you were last on the podcast, and that has to do with a quote from Sir Arthur C. Clark. You know that the into the impossible name, into the impossible ITI. For those of you who didn't know that, Arthur C. Clark did a lot of things. He invented the term podcast unintentionally. He did? Well, yeah. In 2001, a Space Odyssey.

You remember that Dave is going to back in the shuttle to put it back in the space station. And he asks Hal 9,000 open the pod bay doors. And a pod became known as this supporter of information and life's assistance. And then Steve Jobs and one of members of his team took that idea and made the iPod. after which that named the iPad after the Hal 9,000 scene in 2001 Space Odyssey and then podcast grew out of the iPod.

Oh, you're kidding. So that's where it all. Arthur C. Clark also said the only way of determining the limits of the possible is to go beyond them into the impossible. So that's the name of this podcast. But he said another thing. And I think I asked you a couple of related questions,

but I've since added a fourth law of his. He said the following. When I'm not going to say elderly. I cannot say elderly. When I look at you, I cannot say elderly, but he said something like that. He said when an elderly, but distinguished scientist says something is possible, he, and I'm going to say she, is very much certainly correct that it's possible.

But when he says something is impossible, he is very likely to be wrong. I'm not calling you elderly, but I am calling you distinguished. I want to use that and ask you, what have you been wrong about? What have you changed your mind about? What has surprised you? Oh, yes, I'll give you one. Tell me. I remember being at conferences and talking to some brand-new graduate student who wrote on the napkin, he writes,

Lambda equals zero. And we all agreed the cosmological constant. Ah, ha, ha, that's obviously zero. Because they're already observers saying, well, wait a minute, there's something fishy going on, which we could explain if we had a cosmological constant in there. And we all thought on the theorists, we were like so sure. it was not there. We were wrong.

We were wrong. There's dark energy. Well, I don't know if it's cosmological constant, but there's, I don't know if it's dark energy, but there's something weird going on. So we were just wrong. Dead wrong. Yeah. Well, Katie Freeze, it's such a delight to have you back on the podcast, especially in person.

It's been a little while. We did a lovely event, and you penn a couple of years back for our books, and that was a delight. That was fun. And I just can't wait to be, now that you're closer and closer than, Sweden or Michigan. Now you're in Sunny, Texas, where we'll have to get you on the pod circuit as well. But this is, we knew you when. We knew you when we only had, you know, a couple hundred thousand subscribers and followers. Katie, freeze, keep being an inspiration. It's experimentalist. Keep supporting the efforts as a leader. And never, never, ever give up

that wonderful brand that is just so uniquely you. And you, you're a mentor to me. We're similar in age. So it's not like, I knew you when I was a baby. But, um, but, um, but, um, But you have such an effect on collaborations and you're the glue that helps keep us together and thrive. So thank you so much, Katie. Oh, thank you, Brian. It's been great. Let's get you to your lecture. Okay.

Thanks a lot. See you next time. I'm Into the Impossible with Brian Keating, your fearful host. And remember, subscribe, find Katie on Twitter. And find her website as well. And we'll have links to her papers and the new scientist article down below. Thanks a lot. We're out.

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