Uncovering Dark Matter Mysteries with Katherine Freese

Did JWST discover dark stars? Neil deGrasse Tyson and comedian Chuck Nice explore the dark universe and how learning about dark matter could help uncover the mystery of JWST’s primordial objects with theoretical physicist Katherine Freese.

Speaker names marked ? are inferred from speaking time and the show’s known hosts — they are not voice-verified.

• 0:00Neil deGrasse Tyson?

  So Chuck, we brought the dark universe into my office.

• 0:03Chuck Nice?

  Yeah.

• 0:04Neil deGrasse Tyson?

  At the Hayden Planetarium.

• 0:05Chuck Nice?

  You had me at darkzilla, baby.

• 0:07Neil deGrasse Tyson?

  Oh, darkzilla.

• 0:08Chuck Nice?

  Darkzilla. I am all about darkzilling right now.

• 0:11Neil deGrasse Tyson?

  You want to be part of any research project that talks about darkzilla.

• 0:14Chuck Nice?

  And I will never again look at a supermassive black hole the same way.

• 0:19Neil deGrasse Tyson?

  Ooh, there you go. There you go.

• 0:21Chuck Nice?

  Sexy.

• 0:22Neil deGrasse Tyson?

  Dark matter everywhere.

• 0:23Chuck Nice?

  That's it.

• 0:24Neil deGrasse Tyson?

  Throughout the universe. All right. That's what it was. That's how it will be.

• 0:31Neil deGrasse Tyson?

  Welcome to StarTalk, your place in the universe where science and pop culture collide. StarTalk begins right now.

• 0:44Neil deGrasse Tyson?

  This is StarTalk. Neil deGrasse Tyson here, your personal astrophysicist. As always, I got Chuck Nice with me. Chuck, baby.

• 0:52Chuck Nice?

  Hey, what's happening, Neil?

• 0:53Neil deGrasse Tyson?

  That's right.

• 0:54Chuck Nice?

  Your, your personal, ah, no, I'm not your personal comedian. I'm just gonna be honest.

• 1:00Chuck Nice?

  I don't even want to tell the jokes to a paying public.

• 1:04Chuck Nice?

  Let alone be available for somebody personally.

• 1:08Neil deGrasse Tyson?

  Yeah, if, if, if the going gets a little dry or boring, then I mean, comedian.

• 1:13Chuck Nice?

  Exactly.

• 1:14Neil deGrasse Tyson?

  I need a joke about right here.

• 1:15Chuck Nice?

  Right, yes. I'm livening it up.

• 1:19Neil deGrasse Tyson?

  Today, we're calling this episode Going Dark.

• 1:22Chuck Nice?

  Ooh.

• 1:24Neil deGrasse Tyson?

  Going Dark.

• 1:25Chuck Nice?

  All right.

• 1:26Neil deGrasse Tyson?

  You gotta get low. Going Dark.

• 1:27Chuck Nice?

  Going Dark.

• 1:29Neil deGrasse Tyson?

  Dark. Yeah. This is everything dark in the universe.

• 1:33Chuck Nice?

  Okay.

• 1:34Neil deGrasse Tyson?

  Yeah, that, that's a heavily used word lately.

• 1:36Chuck Nice?

  It is.

• 1:37Neil deGrasse Tyson?

  In the cosmos. Now, while I have a little bit of expertise, I don't have the expertise necessary to devote a whole show to it.

• 1:43Chuck Nice?

  Okay.

• 1:44Neil deGrasse Tyson?

  So we combed the cosmos and we found.

• 1:49Chuck Nice?

  In the next galaxy over. We found.

• 1:52Neil deGrasse Tyson?

  We found Katie Freeze. Katie, welcome to StarTalk. Thank you, Neil. Yeah. Happy to be here. We go back, we came up, basically, we're the same generation coming up through the ranks. Yeah. And we saw each other at the same conferences and, and this sort of thing and. We did. So it's just delight to see that, and you've always been interested in these weird stuff in the universe and no one understood what, what it is or what's going on.

• 2:18Chuck Nice?

  Yes.

• 2:18Neil deGrasse Tyson?

  And you're still interested in that.

• 2:19Chuck Nice?

  That is a good source of job security.

• 2:22Speaker 02

  Astroph particle, the little particles that explain the cosmos on the largest scale.

• 2:28Neil deGrasse Tyson?

  Yeah. Ooh.

• 2:29Speaker 02

  Very cool stuff.

• 2:30Neil deGrasse Tyson?

  Yeah, because that's foundational to whatever understanding would be laced on top of that. So we want to know like dark matter, dark energy, dark stars, dark, everything dark. You've made a career of this.

• 2:44Speaker 02

  I guess I have, yeah.

• 2:48Neil deGrasse Tyson?

  So let me get some of your resume here. Director of the Weinberg Institute for Theoretical Physics at UT Austin. Weinberg, that would be Steven Weinberg, I guess.

• 2:57Speaker 02

  Yes.

• 2:58Neil deGrasse Tyson?

  Okay, he ended his career at UT Austin while I was there. He was there and.

• 3:04Speaker 02

  And I noticed you have his book right there, right behind Chuck.

• 3:08Neil deGrasse Tyson?

  Wow. Yeah, it's right here.

• 3:10Speaker 02

  That is the book I learned cosmology from.

• 3:12Neil deGrasse Tyson?

  Oh, yeah.

• 3:13Speaker 02

  Yeah.

• 3:13Neil deGrasse Tyson?

  Yeah.

• 3:14Speaker 02

  I was an experimentalist at Fermilab.

• 3:17Neil deGrasse Tyson?

  Gravitation and cosmology, principles and applications of the general theory of relativity.

• 3:21Speaker 02

  Yeah.

• 3:22Neil deGrasse Tyson?

  Nice.

• 3:24Speaker 02

  Steven Weinberg, one of the creators of the standard model of particle physics. One of the great minds of our time. And his office was three doors down from me. And sadly, he died a couple of years ago.

• 3:36Neil deGrasse Tyson?

  Yeah, he died a few years ago. But then the institute got named in his honor or was it named while he was there?

• 3:40Speaker 02

  No, it was in his honor.

• 3:41Neil deGrasse Tyson?

  Okay.

• 3:42Speaker 02

  And as of last month, we actually have a webpage.

• 3:45Neil deGrasse Tyson?

  Okay, coming along slowly, but it's there. You're also director of the Texas Center for Cosmology and Astroph particle Physics. Damn, professor of physics at Stockholm University. There's a joint position there.

• 3:59Speaker 02

  I got this grant 10 years ago from the Swedish government. $15 million over 10 years to do theoretical cosmology.

• 4:08Neil deGrasse Tyson?

  Nice.

• 4:09Speaker 02

  And the way it works is you spend half the year in your home institution and the other half at Stockholm University.

• 4:14Neil deGrasse Tyson?

  Love it.

• 4:15Speaker 02

  So I've had a blast.

• 4:17Neil deGrasse Tyson?

  Okay, all right, very cool. Director Emerita.

• 4:21Neil deGrasse Tyson?

  Emerita, that's the female singular.

• 4:24Chuck Nice?

  Emeritas.

• 4:24Neil deGrasse Tyson?

  Emeritas, yes, female singular Latin. Of Nordita, the Nordic Institute of Theoretical Physics.

• 4:30Speaker 02

  Yeah.

• 4:30Neil deGrasse Tyson?

  Okay. And.

• 4:32Chuck Nice?

  Is there any place you haven't worked? Maybe this would be quicker.

• 4:35Neil deGrasse Tyson?

  Quicker.

• 4:36Chuck Nice?

  We'll just name the places you have not.

• 4:38Speaker 02

  Do you, if you want to hear all the grad schools I went to before I figured out what I want to do? A long list.

• 4:44Chuck Nice?

  Really?

• 4:44Speaker 02

  Yeah, yeah.

• 4:45Chuck Nice?

  You know, that's.

• 4:46Speaker 02

  I have alumni status everywhere.

• 4:47Neil deGrasse Tyson?

  Yeah, but that, but that also means you know faculty in different places. And so you are, you are very much a fundamental part of the community. When everyone knows you and you go to conferences and the like. 10 years ago, you wrote a book, The Cosmic Cocktail, Three Parts Dark Matter.

• 5:02Speaker 02

  Neil, you wrote a blurb for it.

• 5:04Neil deGrasse Tyson?

  I, I, now that I'm looking at it, I said, I thought I remembered I had a, I blurbbed.

• 5:08Chuck Nice?

  Wow, is that how many blurbs you've written in your life?

• 5:12Neil deGrasse Tyson?

  I'm a blurbing dude.

• 5:13Chuck Nice?

  No, this, this looks familiar to me.

• 5:17Neil deGrasse Tyson?

  So Katie, can you just catch us up on some of what is dark in the universe? So let's just start with the OG dark thing, dark matter.

• 5:31Chuck Nice?

  Dark matter.

• 5:32Neil deGrasse Tyson?

  Okay.

• 5:33Speaker 02

  What's OG?

• 5:35Neil deGrasse Tyson?

  Original gangster.

• 5:37Speaker 02

  Oh, sorry.

• 5:39Chuck Nice?

  You gotta get out more, okay?

• 5:41Neil deGrasse Tyson?

  Okay, so dark matter, it's 85% of the gravity we measure in the universe.

• 5:49Chuck Nice?

  Wow.

• 5:49Speaker 02

  Yeah.

• 5:50Neil deGrasse Tyson?

  But we don't know what it is.

• 5:51Speaker 02

  Yeah.

• 5:52Neil deGrasse Tyson?

  So Katie, if you do, if you also still do not know what it is, what do you think it might be?

• 5:57Speaker 02

  The best bet is that it's some new kind of fundamental particle, so not neutrons and protons.

• 6:03Neil deGrasse Tyson?

  Says the particle physicist.

• 6:04Chuck Nice?

  Of course.

• 6:04Neil deGrasse Tyson?

  Of course she would say that.

• 6:05Chuck Nice?

  Right.

• 6:06Neil deGrasse Tyson?

  She's a particle physicist.

• 6:07Chuck Nice?

  Well, you know, to a hammer, everything's a nail.

• 6:09Neil deGrasse Tyson?

  Okay.

• 6:13Chuck Nice?

  No, I'm joking.

• 6:14Neil deGrasse Tyson?

  Okay.

• 6:14Chuck Nice?

  That only makes sense what you said.

• 6:16Neil deGrasse Tyson?

  All right. And so it could be some kind of exotic particle.

• 6:19Speaker 02

  Yep, yep. Look, we, that's, that's our, that is our best bet.

• 6:23Chuck Nice?

  That's really exciting though. I mean, but how, well, I'm, I'm getting way too far ahead.

• 6:27Neil deGrasse Tyson?

  Aren't you, aren't you backing into that explanation? You're saying, we can't measure it any other way. It must be a particle that doesn't interact with us. But it's real and it's out there even though we can't see it, can't measure it, can't read it, but it has gravity. But are we just backing, is there any other theoretical reason to say that about it?

• 6:48Speaker 02

  Well, yes. So the candidates that I consider the best motivated, most of us do, are the ones that saw that it killed two birds with one stone.

• 6:58Neil deGrasse Tyson?

  Good.

• 6:59Speaker 02

  They were invented in particle theories for reasons other than dark matter to solve problems in particle physics.

• 7:06Neil deGrasse Tyson?

  Ah, so that's, that, that would give you a little more confidence if you have it for one reason and it also solves another.

• 7:13Speaker 02

  Yep.

• 7:13Neil deGrasse Tyson?

  That's good.

• 7:14Speaker 02

  Yes.

• 7:15Neil deGrasse Tyson?

  I didn't know that.

• 7:16Speaker 02

  Yeah, good motivation.

• 7:16Neil deGrasse Tyson?

  Yes. Yeah. Okay. That happened with Einstein. Einstein comes up with a general theory of relativity and there's something called the procession of Mercury's orbit.

• 7:26Speaker 02

  Right.

• 7:26Neil deGrasse Tyson?

  Mercury's orbit around the sun did not exactly follow Newton's laws.

• 7:29Speaker 02

  Okay.

• 7:30Neil deGrasse Tyson?

  And we astronomers, we said, there must be some planet that we can't see that's too close to the sun, lost in the glare and that's tugging on it. That must be it. And we named it. We called it Planet Vulcan.

• 7:39Speaker 02

  Planet Vulcan.

• 7:40Neil deGrasse Tyson?

  We were completely happy just making stuff up.

• 7:43Speaker 02

  Right.

• 7:43Neil deGrasse Tyson?

  To explain what we could not understand. And then Einstein says, here's general theory of relativity. Oh, and by the way, it warped spacetime close to the sun and that accounts for Mercury. Vulcan evaporated overnight.

• 7:56Speaker 02

  Wow, look at that.

• 7:56Neil deGrasse Tyson?

  Over, we didn't, we weren't clutching to it. It was just, it was, we made it up. As a secondary accounting for what, at a second explanation, we, we were all in.

• 8:07Speaker 02

  You know, can I say something about the importance of Einstein that I like to think about it this way?

• 8:11Neil deGrasse Tyson?

  Oh, yeah.

• 8:12Speaker 02

  The people in antiquity must have asked the same questions we do. Like what is out there? What are we, what are we made of? What is the, where are we going? And they had creation myths. Well, we have our own creation myths as of 100 years ago, the hot big bang, based on Einstein's relativity. The difference is that we're right. Think about that in human achievement. That is so amazing. So in the last hundred years, the accomplishments are amazing. One more thing I have to add. Go. The other thing that changed in the last, over the last hundred years? A lot more in people get to do science. Instead of back in the old days, it was a bunch of rich white guys.

• 8:48Neil deGrasse Tyson?

  Yeah.

• 8:48Speaker 02

  Now we have a little more diversity.

• 8:50Neil deGrasse Tyson?

  Right.

• 8:50Speaker 02

  Yay!

• 8:51Chuck Nice?

  Gentleman scientists, yes.

• 8:52Speaker 02

  Was it gentleman scientists?

• 8:54Chuck Nice?

  Gentleman scientists.

• 8:54Speaker 02

  So I deviated from the dark matter question, but I just think this is so amazing, the achievements of humanity that we've accomplished.

• 9:02Neil deGrasse Tyson?

  The social-cultural observations are a fundamental

• 9:04Speaker 02

  Yeah.

• 9:04Neil deGrasse Tyson?

  part of how any of this works at all and happens. And the pace at which things, I think about it, right. It wasn't just a gentleman scientist. It was, like you said, only men, which meant half the population of the world did not participate in this exercise.

• 9:18Chuck Nice?

  Which is why we're so far behind. If only they had allowed women back then. We would actually know what dark matter is right now.

• 9:26Neil deGrasse Tyson?

  By now, long ago.

• 9:28Chuck Nice?

  We'd have figured it out.

• 9:29Neil deGrasse Tyson?

  We'd be floating through the...

• 9:33Neil deGrasse Tyson?

  We definitely would have had flying cars by now, for sure. For sure. So, so does that particle have a name?

• 9:39Speaker 02

  Well, there's two of them.

• 9:41Neil deGrasse Tyson?

  Okay.

• 9:42Speaker 02

  There's...

• 9:42Neil deGrasse Tyson?

  Two candidates.

• 9:43Speaker 02

  Two different candidates, axions and wimps, that both have reasons for existence that have nothing to do with dark matter.

• 9:50Chuck Nice?

  Okay, I just, I'm sorry, but I, wimps? Like, why would you do that to the particle? Like, really? I mean, seriously, this is a monumental discovery or at least...

• 10:03Neil deGrasse Tyson?

  The particle has no emotional investment in its name.

• 10:06Chuck Nice?

  It will, once it finds out it's a wimp! Like...

• 10:10Speaker 02

  Well, there used to be the machos, massive compact halo objects. Now there's the wimps, the weakly interacting massive particles, so...

• 10:16Neil deGrasse Tyson?

  Which was an acronym.

• 10:17Chuck Nice?

  Okay.

• 10:17Speaker 02

  Yeah, two different acronyms.

• 10:19Neil deGrasse Tyson?

  Right, yeah, machos and wimps.

• 10:20Speaker 02

  Machos and wimps.

• 10:25Speaker 02

  These were not my inventions, these names.

• 10:26Chuck Nice?

  That's okay. I just want to know, is there particle lunch money anywhere in this equation?

• 10:31Neil deGrasse Tyson?

  To be taken from...

• 10:35Neil deGrasse Tyson?

  Alright, so we have wimps, weakly interacting... Massive particles, what makes them massive? When I think of particles, I think of very light objects. So where does massive come in on this?

• 10:46Speaker 02

  Well, they weigh about 100 times as much as protons.

• 10:49Neil deGrasse Tyson?

  Wow, okay, so in the particle universe. Yeah, they're massive.

• 10:52Speaker 02

  In the particle universe, they're massive. They're, they're heavy.

• 10:55Neil deGrasse Tyson?

  If they're that massive, and we can detect protons, why can't we detect these massive particles?

• 11:02Speaker 02

  Well, there are four forces of nature.

• 11:04Neil deGrasse Tyson?

  Yes.

• 11:05Speaker 02

  And by definition, all mass feels gravity. But the dark matter doesn't give off light, so it doesn't feel electromagnetic forces.

• 11:13Neil deGrasse Tyson?

  Let's go through the forces again.

• 11:14Speaker 02

  Okay.

• 11:15Neil deGrasse Tyson?

  So we're gonna call gravity a force in this list, okay? And then what else you got?

• 11:18Speaker 02

  Electromagnetism.

• 11:19Neil deGrasse Tyson?

  Which I think we're all familiar with.

• 11:21Speaker 02

  Yes.

• 11:21Neil deGrasse Tyson?

  Light, and it's, it holds our molecules together, and our particles, and the, you know, atoms, and...

• 11:27Speaker 02

  Electromagnetism.

• 11:28Neil deGrasse Tyson?

  Nice.

• 11:32Neil deGrasse Tyson?

  A demonstration of electro... We can punch chalk. Punch chalk. That's electromagnetism. If it weren't for electromagnetism, I wouldn't have felt that.

• 11:40Neil deGrasse Tyson?

  Cool. And, and I think, we, we did a little bit in Cosmos about this. You're, you're not actually touching each other. That there's a field, you're reacting to a field that's set up. And it feels like you're touching them.

• 11:53Speaker 02

  Right.

• 11:53Neil deGrasse Tyson?

  But if you really zoomed in, it's just fields.

• 11:56Speaker 02

  Really?

• 11:56Neil deGrasse Tyson?

  They're resisting each other.

• 11:57Speaker 02

  Oh, okay.

• 11:57Neil deGrasse Tyson?

  Yeah.

• 11:58Speaker 02

  Cool.

• 11:58Neil deGrasse Tyson?

  At, at the tiniest scale, you're just... There's a whole, we did like a half a whole episode on Cosmos on that. Excellent. Yeah, yeah. But, so, okay, so...

• 12:07Speaker 02

  The strong force.

• 12:08Neil deGrasse Tyson?

  Strong force.

• 12:09Speaker 02

  Which holds our nuclei together.

• 12:10Neil deGrasse Tyson?

  Yes.

• 12:11Speaker 02

  And the weak force.

• 12:12Neil deGrasse Tyson?

  The weak force, which...

• 12:14Speaker 02

  Is responsible for some types of radioactivity, like uranium decay.

• 12:18Neil deGrasse Tyson?

  So these are completely different forces. Don't have anything to do with each other.

• 12:21Speaker 02

  Nope.

• 12:22Neil deGrasse Tyson?

  Okay, yet they all come together to make the world as we know it.

• 12:25Speaker 02

  Yeah.

• 12:25Neil deGrasse Tyson?

  Okay, so now, you have ways that particles know about each other, and interact with each other.

• 12:33Speaker 02

  Through these forces.

• 12:33Neil deGrasse Tyson?

  Through these forces.

• 12:34Speaker 02

  Yeah.

• 12:35Neil deGrasse Tyson?

  And I guess what you're telling me is that you've got a... Massive particle that does not use these forces to interact, other than gravity.

• 12:44Speaker 02

  Well, no, we think the WIMP, weakly interacting massive particle.

• 12:49Neil deGrasse Tyson?

  Not no interacting.

• 12:50Speaker 02

  Feels, yeah, it feels the weak force.

• 12:52Neil deGrasse Tyson?

  Oh.

• 12:53Speaker 02

  So of these four forces, it's got gravity.

• 12:55Neil deGrasse Tyson?

  That's where you got the weekly.

• 12:55Speaker 02

  And that's where the name weakly interacting comes from.

• 12:58Neil deGrasse Tyson?

  Oh, not that it interacts once every seven days.

• 13:02Speaker 02

  Well, there are, you know, a reporter once.

• 13:04Neil deGrasse Tyson?

  Weekly, that's a joke.

• 13:05Speaker 02

  Oh, weekly, oh, God, oh, God, I can't believe I didn't get it. Because the answer is actually more like monthly.

• 13:14Neil deGrasse Tyson?

  Oh, the rate at which you might detect it.

• 13:16Speaker 02

  No, the, there are billions going through your body every second.

• 13:20Neil deGrasse Tyson?

  Billions of.

• 13:21Speaker 02

  If they exist, these WIMP particles, there are billions going through your body, but about.

• 13:25Neil deGrasse Tyson?

  And they go through because they don't interact.

• 13:26Speaker 02

  Well, except about once a month, one of them would hit one of your nuclei.

• 13:31Neil deGrasse Tyson?

  And interact.

• 13:32Speaker 02

  And, and interact.

• 13:34Neil deGrasse Tyson?

  Okay.

• 13:34Speaker 02

  By the weak force.

• 13:36Neil deGrasse Tyson?

  Oh.

• 13:36Speaker 02

  Weak interactions with a nucleus in your body, which is, you know, harmless.

• 13:41Chuck Nice?

  Right.

• 13:42Neil deGrasse Tyson?

  We think.

• 13:42Chuck Nice?

  Yeah, well, let's hope.

• 13:44Neil deGrasse Tyson?

  It's the same thing, we, we hope.

• 13:46Chuck Nice?

  We hope it's harmless.

• 13:47Neil deGrasse Tyson?

  So what about the theory that gives us this particle can tell you that it will interact at all?

• 13:55Speaker 02

  So the original motivation beyond dark matter is supersymmetry.

• 14:01Neil deGrasse Tyson?

  Okay, supersymmetry. We did supersymmetry recently on an episode.

• 14:05Chuck Nice?

  Right.

• 14:05Neil deGrasse Tyson?

  I think we had Brian Greene in here.

• 14:06Chuck Nice?

  Yes, we did.

• 14:07Neil deGrasse Tyson?

  Talking about supersymmetry.

• 14:08Chuck Nice?

  Yeah.

• 14:08Neil deGrasse Tyson?

  Where, let me repeat it if I think I understand it. In supersymmetry, we have our particle universe, electrons, protons, neutrons, right? At a higher energy level, a whole counterparts to those particles exist, and we see them in particle accelerators.

• 14:23Chuck Nice?

  Right.

• 14:23Neil deGrasse Tyson?

  So we have a heavier electron, okay, and heavier quarks, which make up the neutron and the proton. And then there's a third level, okay? And so there's three layer, energy layers in the universe. We only can really access the other two in particle accelerators and in energetic places in the universe.

• 14:41Chuck Nice?

  Right.

• 14:41Neil deGrasse Tyson?

  Okay, so that's the standard model, I guess, right?

• 14:43Speaker 02

  That's the standard model.

• 14:44Neil deGrasse Tyson?

  So the supersymmetry, are you telling me, I think if I remember, there's an entire other counterpart to all of these particles, not just a fourth layer up there, a whole other counterpart.

• 14:56Speaker 02

  For every particle that we have in the standard model, there would be a partner. And it has to be a heavier one, so that you double the number of particles, but they're heavier, which is why we don't see them every day. And the heaviest ones decay to lighter ones, to lighter ones, da-da-da-da-da, until you get to the lightest one, that is a dark matter candidate. And that makes a great wimp.

• 15:23Neil deGrasse Tyson?

  They can't decay into our world of particles.

• 15:25Speaker 02

  No, they can't.

• 15:26Neil deGrasse Tyson?

  Why not?

• 15:27Speaker 02

  No.

• 15:28Neil deGrasse Tyson?

  Wait, wait, if you're making all this up anyway, just declare it so.

• 15:31Chuck Nice?

  Oh, man.

• 15:31Neil deGrasse Tyson?

  Let it be so.

• 15:34Chuck Nice?

  So let it be written, so let it be done.

• 15:37Speaker 02

  Well, there are symmetries, and so they have...

• 15:40Neil deGrasse Tyson?

  So the symmetries force some of the discussion on it?

• 15:42Speaker 02

  Yeah, they have their own interactions, their own gauge groups, their own symmetries, and there's a symmetry called R parity, which if that's conserved, then you can't interact with our sector.

• 15:54Neil deGrasse Tyson?

  So R stands for what in that?

• 15:56Speaker 02

  Uh, the name is R. Capital R, dash, parity.

• 16:01Neil deGrasse Tyson?

  Okay.

• 16:01Speaker 02

  Doesn't stand for anything.

• 16:02Neil deGrasse Tyson?

  Okay, so when I see particle physicists hang out together, I hear the word gauge, come a gauge symmetries or gauge things, and I can't claim that I know what they're talking about. Is a gauge a thing, you know, animal, vegetable, mineral, person, place, or thing? How do I come to understand what gauge means?

• 16:22Speaker 02

  It refers to, in mathematics, group theory. So there are different groups that describe these different fundamental forces.

• 16:31Neil deGrasse Tyson?

  Okay.

• 16:31Speaker 02

  And so the gauge group for the weak interactions is different than the gauge group for the strong interactions or the electromagnetic interactions.

• 16:40Neil deGrasse Tyson?

  Okay, all right, so it's a way to...

• 16:43Chuck Nice?

  Is it like classifications, kind of, or organizational?

• 16:47Speaker 02

  It's organizational, but it also talks about how things interact with each other.

• 16:51Neil deGrasse Tyson?

  Okay, okay.

• 16:52Speaker 02

  So within the strong interactions, the way the strong force works, you have the particles that are made, as you know, neutrons and protons, and inside there you have quarks and gluons.

• 17:03Neil deGrasse Tyson?

  Right.

• 17:04Speaker 02

  And the gauge group defines how those interactions happen.

• 17:08Neil deGrasse Tyson?

  Okay, so it's a recipe in a sense.

• 17:11Speaker 02

  Yeah, I guess you could say that.

• 17:12Neil deGrasse Tyson?

  Okay, an interaction recipe.

• 17:14Chuck Nice?

  Nice.

• 17:15Neil deGrasse Tyson?

  You're a quark, I'm a quark, let's check the gauge table and see how we interact.

• 17:20Chuck Nice?

  Sounds like a great cooking show. I love it.

• 17:23Speaker 02

  And if you're a neutrino, you don't interact with anything at all, other than with weak interactions. So wimps are like that, like neutrinos in that sense.

• 17:45Speaker 03

  Hello, I'm Vicky Brook Allen, and I support StarTalk on Patreon. This is StarTalk with Neil deGrasse Tyson.

• 18:01Neil deGrasse Tyson?

  So this reminds me of the story of the prediction and discovery of the neutrino, where there was some particle interaction, and there was a missing accounting of the energy. So it didn't add up? It didn't add up. All the charges were there, everything else was there, the charges were there. But something didn't add up that carried energy away. And so since the charges add up, it had to be neutral. Right. And it was a little bit of energy, a little, and so I guess.

• 18:33Speaker 02

  Pauli.

• 18:34Neil deGrasse Tyson?

  Pauli predicts it.

• 18:35Speaker 02

  Yeah.

• 18:36Neil deGrasse Tyson?

  Wolfgang Pauli?

• 18:37Speaker 02

  Yeah.

• 18:37Neil deGrasse Tyson?

  Oh, okay. You walk in a room and your name is Wolfgang, people just gotta shut up and listen. They just give you their wallet.

• 18:46Neil deGrasse Tyson?

  That's another level of influence. So when we go firmly coins the term neutrino, or little neutral one. But there's a prediction that something's there that no one has seen.

• 18:58Speaker 02

  Yeah.

• 18:58Neil deGrasse Tyson?

  And I think that this is a very powerful position to be in as a particle physicist. By experiment, you trust the laws of physics so thoroughly, that when something doesn't add up, you say, there's something else we haven't even found yet. Start looking. Start looking. Start looking.

• 19:16Speaker 02

  Well, that's the fun of being a theorist, that we get to propose things, to explain.

• 19:24Speaker 02

  Unexplained data, so we get to be creative, we get to invent stuff.

• 19:28Neil deGrasse Tyson?

  We make stuff up.

• 19:29Speaker 02

  We make stuff up.

• 19:31Speaker 02

  We do sci-fi.

• 19:32Chuck Nice?

  But it's not crazy, I mean, you are still constrained. You're not making it up out of nothing, though.

• 19:37Speaker 02

  No.

• 19:38Chuck Nice?

  It's not a story, you know?

• 19:39Speaker 02

  Yeah, you have to satisfy the laws of physics, and you have to build on the existing information you have, so it's actually not easy to come up with. Usually, you come up with an idea on the back of the envelope, and then within a day, you realize, oops, this idea is dead. So that's 99% of the time. So for an idea to survive that process, it actually, it's not easy, and it has to be a pretty good idea.

• 20:02Neil deGrasse Tyson?

  The public needs to recognize, we joke about you just making stuff up, but you are constrained by nature.

• 20:08Speaker 02

  Big time.

• 20:09Neil deGrasse Tyson?

  Which is your ultimate judge, jury, and?

• 20:12Chuck Nice?

  Executioner?

• 20:13Neil deGrasse Tyson?

  There it is.

• 20:15Speaker 02

  Okay.

• 20:16Chuck Nice?

  He gave me the ominous one, of course.

• 20:18Neil deGrasse Tyson?

  Yeah, yeah, yeah.

• 20:20Chuck Nice?

  So now, wait, back to neutrinos, though. Did we ever prove that that's what it was?

• 20:25Speaker 02

  Yes.

• 20:25Chuck Nice?

  That it is the neutrino?

• 20:26Speaker 02

  Oh, yes, yes, yes.

• 20:27Neil deGrasse Tyson?

  It took decades later, but yes. Yes, we discovered the neutrino. It is very weakly interacting.

• 20:32Speaker 02

  Yeah, and they're studied every day. They're created and studied every day in particle accelerators. And in fact, the big push in the particle experimental community in the United States is to build experiments to measure neutrino properties. So you create them, and a particle accelerator, you shoot them through the earth underground for thousands of miles, and then you put your detector on the other end.

• 20:53Neil deGrasse Tyson?

  Right. And it doesn't interact with the earth.

• 20:55Speaker 02

  Right.

• 20:56Neil deGrasse Tyson?

  It's like the earth isn't even there. Right.

• 20:57Speaker 02

  Yeah, that's right.

• 20:58Chuck Nice?

  Is that, that's why they say neutrinos are just passing through the earth all the time?

• 21:02Neil deGrasse Tyson?

  Right.

• 21:03Chuck Nice?

  Got you.

• 21:03Speaker 02

  And wimps are somewhat like that, because they also only have weak interactions, which is why they're so damn hard to detect.

• 21:12Neil deGrasse Tyson?

  So, well, let's go back for a bit, because... You want to, a theorist needs to make a prediction.

• 21:16Speaker 02

  We did, yeah.

• 21:17Neil deGrasse Tyson?

  And so, you predicted what?

• 21:20Speaker 02

  We, well, I did the scattering rates of particles off of, if you were to build a detector out of some atom. So how much, how much energy would you get from the wimp hitting that nucleus?

• 21:32Neil deGrasse Tyson?

  Because most would pass through.

• 21:33Speaker 02

  Most would pass through.

• 21:34Neil deGrasse Tyson?

  So the scattering cross-section, I think that's what it's called, right? You send something through, what fraction of everything you send through is actually going to interact?

• 21:42Chuck Nice?

  Right.

• 21:42Neil deGrasse Tyson?

  And then you get a number, and you design your experiment around that number?

• 21:46Speaker 02

  Yeah.

• 21:46Neil deGrasse Tyson?

  Okay.

• 21:47Speaker 02

  Yeah.

• 21:47Chuck Nice?

  And, and are you measuring that interaction by what's left over, what's no longer there? Or how are you measuring that interaction?

• 21:55Speaker 02

  These interactions are elastic. That means that the particle goes vroom vroom, scatters off.

• 22:00Chuck Nice?

  Okay.

• 22:00Speaker 02

  But it deposits energy in the detector.

• 22:03Chuck Nice?

  So it deposits energy.

• 22:04Speaker 02

  You gotta measure that energy somehow. Very small amount of energy. So that's, and these experiments have to be deep underground because you have to get away from competing signals that would be a lot bigger. So you have to go a mile underground, and you have to sit there for a long time.

• 22:19Neil deGrasse Tyson?

  So you have things like cosmic rays coming in from space.

• 22:22Chuck Nice?

  Other particles that could just actually interfere with the sun even.

• 22:25Speaker 02

  Cosmic rays have electromagnetic interactions, which are, that's a much stronger force and happens much more frequently. So you'd have a million of those for every wimp, and you'd never be able to dig out the wimp. So you gotta go underground because the cosmic rays do get stuck in the earth.

• 22:38Neil deGrasse Tyson?

  You're stuck in the earth because earth and cosmic rays are the same stuff.

• 22:41Speaker 02

  Yes.

• 22:42Neil deGrasse Tyson?

  Right? I mean, there's some transparency, but they know how to interact with each other very nicely.

• 22:46Speaker 02

  Shall we demonstrate electromagnetic interactions again?

• 22:50Neil deGrasse Tyson?

  They interact. But in those experiments, is, does the, does the interacted nucleus give off light or something, and you see the light? Or is it the temperature of the vat? Or like, what is it?

• 23:02Speaker 02

  Well, you know, there's different experimental techniques. And so either one of those can happen. So you're depositing energy so that can just be, you look for the heat that got deposited. It could create some light flashes you look for. Depends on the type of experiment.

• 23:14Neil deGrasse Tyson?

  Okay.

• 23:15Chuck Nice?

  Okay.

• 23:15Neil deGrasse Tyson?

  I have not heard lately, so I'm going to presume we have yet to make such a discovery.

• 23:21Speaker 02

  Most of the experiments have found nothing, with one exception, and that's the Dama experiment. That is-

• 23:27Neil deGrasse Tyson?

  Jeffrey Dahmer was a physicist. Did you know this?

• 23:29Chuck Nice?

  No, I thought he was a cannibal.

• 23:32Speaker 02

  Oh geez.

• 23:33Chuck Nice?

  Oh no, that's Jeffrey Dahmer. I'm sorry.

• 23:36Neil deGrasse Tyson?

  No, Donner, what is this experiment?

• 23:38Speaker 02

  Dama, I don't know what it is, dark matter experiment of some sort. But it's in Italy and it's underneath mountains outside of Rome, Apennine Mountains. So the Dama experiment is seeing something called an annual modulation of the signal. It's something we predicted that the count rate should be the highest in June and the lowest in December, and they've got 15 years' worth of data with this annual modulation in it. So they're definitely seeing what we predicted, but nobody knows what to make of it because they won't share their data, which is unusual, mostly.

• 24:12Neil deGrasse Tyson?

  Is this because of the sun and our difference in distance from the sun?

• 24:15Speaker 02

  It's because the Earth is moving around the sun.

• 24:16Neil deGrasse Tyson?

  Right.

• 24:17Speaker 02

  And that means that the relative speed between us and the particles changes depending on the time of year.

• 24:23Neil deGrasse Tyson?

  Okay.

• 24:24Speaker 02

  The sun is moving around the center of the galaxy, so it looks like we're moving into a wind of wimps. And so that looks, it's like when it rains on your windshield, it looks like you're going

• 24:36Chuck Nice?

  Like you drive into a storm.

• 24:39Neil deGrasse Tyson?

  It looks like it's coming at you.

• 24:40Speaker 02

  So it looks like it's coming at you, and that relative speed is really important, but because the Earth goes around the sun, when you're going into that wind, you're going to get a higher count rate. And when you're coming out of it.

• 24:51Neil deGrasse Tyson?

  And the wind is coming where, the center of the galaxy? Where's it coming from?

• 24:54Speaker 02

  Well, we're going around, the sun is going around the center of the galaxy.

• 24:57Neil deGrasse Tyson?

  But why would it be two different directions?

• 25:00Speaker 02

  Oh, okay, so the two different directions are just because the Earth is going around the sun. Okay, so the sun's going like this, and the Earth is going around it.

• 25:09Neil deGrasse Tyson?

  Which way, which way the wind's coming in?

• 25:11Speaker 02

  The wind is coming this way.

• 25:12Neil deGrasse Tyson?

  Why is it coming, that's what I'm asking.

• 25:13Speaker 02

  Because the sun's going that way.

• 25:15Neil deGrasse Tyson?

  Oh, okay.

• 25:16Speaker 02

  It's just the motion of the sun.

• 25:18Neil deGrasse Tyson?

  Just the sun.

• 25:18Speaker 02

  That creates an artificial wind.

• 25:20Neil deGrasse Tyson?

  Whether going with it or against it?

• 25:22Speaker 02

  Yeah.

• 25:23Neil deGrasse Tyson?

  Got it.

• 25:24Speaker 02

  Yeah.

• 25:25Neil deGrasse Tyson?

  Got it, okay.

• 25:25Speaker 02

  So it's not a real wind, it just looks like a wind because we're moving into it.

• 25:28Neil deGrasse Tyson?

  Okay, now, if dark matter doesn't interact with us, it kind of also doesn't interact with itself, or does it?

• 25:35Speaker 02

  Oh, yes, it does, it annihilates. So when two dark matter particles hit each other... They annihilate, which means they're, they turn into something else.

• 25:44Neil deGrasse Tyson?

  Then how can you make an object out of dark matter?

• 25:47Speaker 02

  I don't make an object out of dark matter. Do you make objects out of dark matter?

• 25:51Neil deGrasse Tyson?

  I thought you made a dark matter star.

• 25:53Speaker 02

  No, I'm, uh, dark stars are made almost entirely of hydrogen and helium. Ninety-nine point nine-nine percent. And it's a little bit of dark matter.

• 26:02Neil deGrasse Tyson?

  Like all stars, like all stars of that, okay?

• 26:04Speaker 02

  Yeah, and, uh, but, well, no, it's only hydrogen and helium from the big bang, because these are the first stars that ever formed.

• 26:10Neil deGrasse Tyson?

  Got it.

• 26:10Speaker 02

  So they don't have anything else in there, no carbon, nitrogen, oxygen.

• 26:13Neil deGrasse Tyson?

  All I meant was, all stars have hydrogen and helium in them, that's all I meant.

• 26:16Speaker 02

  Yeah, yeah, yeah, yeah, yeah. So it's an ordinary, it's ordinary matter, but it's powered by dark matter. So, that, that's because you have a lot of dark matter in there, and those dark-

• 26:26Neil deGrasse Tyson?

  Leftover from the early universe.

• 26:28Speaker 02

  Okay, let's back up. The dark stars would have been the first stars to form in the history of the universe, when it was 200 million years old, and we're now at 14 billion years.

• 26:36Neil deGrasse Tyson?

  And dark, this is your baby, these dark stars.

• 26:37Speaker 02

  That's my baby.

• 26:38Neil deGrasse Tyson?

  This is your birthday.

• 26:39Speaker 02

  This is my baby.

• 26:39Neil deGrasse Tyson?

  Yes, okay, go on.

• 26:40Speaker 02

  Yeah, yeah.

• 26:41Neil deGrasse Tyson?

  Go on.

• 26:41Speaker 02

  Yeah, and back in the early universe, you, these things would have formed at the centers of protogalaxies.

• 26:50Neil deGrasse Tyson?

  Yes.

• 26:50Speaker 02

  Small objects that are gonna merge together to make our galaxy later on.

• 26:54Neil deGrasse Tyson?

  The gravitational action was.

• 26:56Speaker 02

  Yeah, and so smack in the middle of these protogalactic objects, they're called mini halos, that's where you would have collapsing clouds of hydrogen that are on their way to forming stars. In the standard picture, they keep collapsing and make tiny little objects a thousandth of the mass of the sun, and then accrete back up to about a hundred times the mass of the sun. But, nobody asked, well, yeah, but if you're smack in the middle of the protog galaxy, what about the dark matter? What does that do?

• 27:22Neil deGrasse Tyson?

  Right.

• 27:22Speaker 02

  So that was the question that we asked, and it changes-

• 27:25Neil deGrasse Tyson?

  You would be enclosing some volume of dark matter in doing so.

• 27:28Speaker 02

  Well, there's a lot of dark matter at the center of our galaxy, at the center of the protog galaxy. The fact that you're smack in the middle is what counts.

• 27:36Neil deGrasse Tyson?

  Got it.

• 27:36Speaker 02

  Because that's where you got a lot of dark matter.

• 27:38Neil deGrasse Tyson?

  Got it.

• 27:38Speaker 02

  And when you got a lot of dark matter, you get a lot of dark matter annihilation.

• 27:41Chuck Nice?

  Hmm, and why, why the coalescing of dark matter at the center of the galaxy?

• 27:45Neil deGrasse Tyson?

  Because it's response to gravity. We knew that.

• 27:46Chuck Nice?

  Oh, that's right, because at the center of every galaxy, there's a black hole, is that the deal?

• 27:51Speaker 02

  No, it doesn't matter about the black hole.

• 27:53Neil deGrasse Tyson?

  Doesn't matter about the black hole.

• 27:53Speaker 02

  No, no, it's just, yeah, if you go at, go to the center of any massive object, a galaxy, a cluster, anything, there's a ton of dark matter in there, and then as you move out, there's less, it gets less and less dense in terms of the dark matter.

• 28:08Neil deGrasse Tyson?

  So just to be clear, there's more, if dark matter is a matter is a thing, there's more of it than our matter.

• 28:15Chuck Nice?

  Right.

• 28:16Neil deGrasse Tyson?

  So it's been analogized, I love this analogy, correct me if I'm wrong here, that when we look at our galaxies and the light from them, the stars, this is sea froth on an ocean of dark matter that's what's actually driving where everything collects in the universe.

• 28:38Chuck Nice?

  Exactly.

• 28:39Neil deGrasse Tyson?

  Is that a fair characterization?

• 28:41Speaker 02

  That's great. Yeah.

• 28:42Neil deGrasse Tyson?

  Yeah, and here we are thinking the visible stars and galaxies, that's the thing. No, the dark matter dictating everything.

• 28:48Speaker 02

  You know, this is a weird thought. The way stars are moving around the center of the galaxy, they would get flung out of the galaxy if it weren't for the dark matter providing the gravitational pull to keep them in.

• 29:00Chuck Nice?

  Right.

• 29:00Speaker 02

  So we're, we desperately need dark matter, even for the Milky Way.

• 29:05Neil deGrasse Tyson?

  Vera Rubin first showed that.

• 29:06Speaker 02

  Yes.

• 29:07Neil deGrasse Tyson?

  1976.

• 29:08Speaker 02

  Yes.

• 29:08Neil deGrasse Tyson?

  That you figure out how fast all the stars are moving, then you're going too fast.

• 29:12Chuck Nice?

  Right, to be, to stay.

• 29:14Neil deGrasse Tyson?

  To stay.

• 29:14Chuck Nice?

  You're going too fast to be.

• 29:15Neil deGrasse Tyson?

  You have enough speed to escape and you're not escaping.

• 29:17Chuck Nice?

  Exactly. How is that kid staying on the merry-go-round? That he's not fat enough to stay on the merry-go-round.

• 29:24Neil deGrasse Tyson?

  Massive enough.

• 29:25Chuck Nice?

  Massive enough. Very good, very good. Yeah, he should have been flung off.

• 29:29Neil deGrasse Tyson?

  Flung off, and so some extra forces are holding it.

• 29:32Chuck Nice?

  Right.

• 29:33Neil deGrasse Tyson?

  Behold, this mysterious problem.

• 29:36Chuck Nice?

  This is what is so fascinating about the whole thing. It's like, you guys are, it's, all the information allows you to infer all this other information.

• 29:47Speaker 02

  Yeah.

• 29:47Chuck Nice?

  Crazy.

• 29:48Neil deGrasse Tyson?

  That's how it works.

• 29:49Chuck Nice?

  It's friggin' crazy.

• 29:50Neil deGrasse Tyson?

  That's how it works. And it worked because the information that we trust.

• 29:55Chuck Nice?

  Right.

• 29:56Neil deGrasse Tyson?

  We trust on a level that gives us the confidence that the next thing we invent might have some validity. Because this worked.

• 30:05Speaker 02

  And we have to test it, we have to find it, we have to prove it, experimentally or observationally.

• 30:10Chuck Nice?

  Right.

• 30:11Neil deGrasse Tyson?

  Yeah.

• 30:11Chuck Nice?

  Wow.

• 30:30Neil deGrasse Tyson?

  So Katie, give me an update to your babies here, your dark stars. Are they still, are people still contemplating them?

• 30:39Speaker 02

  Oh, yeah.

• 30:40Neil deGrasse Tyson?

  And JWST, which is exquisitely tuned to observe the early universe and the birth of galaxies, seems to me ought to be right where you needed to be to test your hypothesis.

• 30:54Speaker 02

  Well, these dark stars start out when they first form, being about as massive as the sun. But they can, they're really weird. They're in distance 10 times, their radius is 10 times the distance between the earth and the sun. Isn't that weird? They're big, puffy objects. And they keep, and they're very, very cool. They're not hot, no fusion, no core, nothing. They keep accreting and growing and growing until they can get a million times as massive as the sun and a billion times as bright in the early universe. Now you've got something you can see, you can look for.

• 31:27Neil deGrasse Tyson?

  Whoa. Because you're... Wait, wait, wait. So if it's not undergoing fusion, where does the brightness come from?

• 31:34Speaker 02

  Dark matter heating. Dark matter heating.

• 31:37Neil deGrasse Tyson?

  There it is.

• 31:38Speaker 02

  Yep.

• 31:39Neil deGrasse Tyson?

  Dark matter, don't you run out of dark matter? It just keeps annihilating itself. You're gonna run out.

• 31:43Speaker 02

  Well, there's an awful, you're right, eventually you will. But then that mini halo is gonna merge with other mini halos. And if the dark star stays at the center, it can keep going, it can keep getting more and more dark matter.

• 31:56Neil deGrasse Tyson?

  Blame it. Wait, so if your dark star uses up all the dark matter in it, then it's just a big ball of gas?

• 32:02Speaker 02

  Yeah, and guess what happens to the million solar mass? Something that weighs a million times as much as the sun with no heat source anymore. Kump, black hole.

• 32:12Speaker 02

  Supermassive black hole, which no one knows how to explain.

• 32:15Neil deGrasse Tyson?

  So you can explain that?

• 32:16Speaker 02

  Yes, the big black hole problem.

• 32:17Neil deGrasse Tyson?

  We don't know how to make a big black hole.

• 32:19Speaker 02

  No, we don't.

• 32:20Neil deGrasse Tyson?

  We had no idea.

• 32:21Chuck Nice?

  There is no cosmic shovel to make a big black hole.

• 32:24Neil deGrasse Tyson?

  And so, but, and you, and you make it for free?

• 32:26Speaker 02

  Yeah.

• 32:27Chuck Nice?

  Wow, look at that.

• 32:27Speaker 02

  You know why I said you try ideas and they're usually dead within three days? Well, this was the opposite. Somebody told us, oh, did you know you just solved a big problem? I said, what problem? The big black hole problem.

• 32:37Neil deGrasse Tyson?

  The massive black hole in the center of the galaxy.

• 32:39Speaker 02

  Supermassive black holes.

• 32:40Neil deGrasse Tyson?

  We, we were making, we were saying, well, there must be some way to channel matter for, the, the, the big problem here unstated is it's very hard to get to the center of anything.

• 32:49Chuck Nice?

  Right.

• 32:50Neil deGrasse Tyson?

  If you have any motion at all. Because if you can go to the center, it meant you, you had no angular momentum around it. You have to like, so people say, let's just take our garbage and just send it to the sun.

• 33:02Chuck Nice?

  Right.

• 33:02Neil deGrasse Tyson?

  Can't do that. Cause all of our garbage is moving at 30 kilometers per second with the earth around the sun. You have to stop, you have to take that speed to zero. Then it'll fall towards the sun. If it has any other speed, it's just gonna orbit the sun.

• 33:18Chuck Nice?

  It'll go with you. It's on the, it's going on a ride with you.

• 33:21Speaker 02

  It could, and it would be, it would be annually modulating, like on the earth going around the sun, the garbage going around the sun.

• 33:26Chuck Nice?

  Yes, right. That is, that is so cool.

• 33:30Neil deGrasse Tyson?

  No, I've never heard that before.

• 33:31Chuck Nice?

  No, but you're absolutely right.

• 33:32Neil deGrasse Tyson?

  There's no other.

• 33:33Chuck Nice?

  You can't just shoot your garbage at the sun.

• 33:36Neil deGrasse Tyson?

  At the sun, because it's going sideways.

• 33:38Chuck Nice?

  It'll just start falling around the sun the same way you do.

• 33:41Neil deGrasse Tyson?

  Correct.

• 33:41Chuck Nice?

  Correct.

• 33:42Neil deGrasse Tyson?

  That's amazing.

• 33:42Chuck Nice?

  You know what it'll do?

• 33:43Neil deGrasse Tyson?

  It'll have an orbit that'll have it re-intersect earth.

• 33:46Chuck Nice?

  Right.

• 33:46Neil deGrasse Tyson?

  Yes.

• 33:46Chuck Nice?

  And then your garbage just comes back.

• 33:48Neil deGrasse Tyson?

  Right back in your face. Okay, so you solved the supermassive black hole problem.

• 33:52Chuck Nice?

  Wow.

• 33:53Neil deGrasse Tyson?

  So they'd be accreting the dark matter themselves, wouldn't they?

• 33:57Speaker 02

  But the black holes. So most of the accretion is ordinary matter. The dark star accreted, creates ordinary, more and more ordinary matter.

• 34:03Neil deGrasse Tyson?

  No, no, no.

• 34:03Speaker 02

  More and more hydrogen.

• 34:04Neil deGrasse Tyson?

  If the supermassive black hole is in the center of the galaxy.

• 34:06Speaker 02

  Oh.

• 34:07Neil deGrasse Tyson?

  And, and dark matter centers on the centers of galaxies, rather. Galaxy center on the centers of the dark matter. Why wouldn't the black hole also be eating dark matter?

• 34:16Speaker 02

  Yeah, I guess it is.

• 34:18Neil deGrasse Tyson?

  Okay.

• 34:19Speaker 02

  And then there could be more dark matter around there that's annihilating, and you can look for signatures of that dark matter annihilation.

• 34:24Neil deGrasse Tyson?

  Okay, so when it annihilates?

• 34:25Speaker 02

  Same annihilation, the same annihilation that happened in the early universe.

• 34:29Neil deGrasse Tyson?

  And it doesn't give off photons that we met?

• 34:31Speaker 02

  Yes.

• 34:32Neil deGrasse Tyson?

  Regular photons, not dark matter?

• 34:34Speaker 02

  Nope, regular photons, yep, gamma rays, so high-energy photons.

• 34:39Neil deGrasse Tyson?

  Oh.

• 34:39Speaker 02

  That people in the Fermi satellite is looking at the gamma ray sky.

• 34:45Neil deGrasse Tyson?

  Named after Emilio Fermi.

• 34:46Speaker 02

  Named after Emilio Fermi, and it has.

• 34:49Neil deGrasse Tyson?

  It specializes in what part of the spectrum?

• 34:51Speaker 02

  Gamma rays.

• 34:52Neil deGrasse Tyson?

  Gamma rays, okay.

• 34:53Speaker 02

  And it sees an excess coming from the center of our galaxy. And there are those who speculate, oh, that's dark matter annihilation, which is, would be so cool. Now, the trouble is, there's a lot of astrophysics at the center of the galaxy.

• 35:06Neil deGrasse Tyson?

  Yeah.

• 35:06Speaker 02

  There are.

• 35:07Neil deGrasse Tyson?

  A lot of things that can make that.

• 35:08Speaker 02

  There are a lot of other things that could make the same signal, so we're not sure.

• 35:11Neil deGrasse Tyson?

  Okay, but Katie, when you get your Nobel Prize, will you invite us to Stockholm?

• 35:15Speaker 02

  Well, you know, I already spent 10 years in Stockholm. I've already gone to that Nobel party a number of times. And I have, and hold on, no. My point is, I know exactly how to sneak people in.

• 35:29Neil deGrasse Tyson?

  Oh, which back door was that, Amber?

• 35:33Neil deGrasse Tyson?

  No, I wouldn't want you to sneak in, I want you to announce us.

• 35:35Speaker 02

  I will invite you.

• 35:36Neil deGrasse Tyson?

  I don't want to be snuck in. I want to be announced.

• 35:40Neil deGrasse Tyson?

  And, you know, that's a Lord, Lord, Lord Nice, Lord Nice, right. All right, so you solved the black hole problem, the supermassive black hole problem. That's amazing. How does J W S T contribute to this?

• 35:52Speaker 02

  We had this idea in 2007, the idea of dark stars. And then in 2010, John Mather, the Nobel laureate, who is the guy behind the James Webb Space Telescope, said to us, hey, give us predictions. These are bright early objects, we can look for them. So we did, so we predicted what the spectrum should be. So how much light at different frequencies would be coming out of these objects? And they're only made of hydrogen and helium, so you better not see signs of any other elements in there. So when the James Webb turned on, we were ready to compare the early universe objects that they're seeing to our dark star predictions.

• 36:30Speaker 02

  Now, one dark star is, can be as bright as an entire early galaxy of stars, and so telling the difference, well, you, there aren't very many spectra yet. But at the time, we did this a year ago, there were five objects with spectra that we could get our hands on, and three of them were dead on perfect matches to dark stars. But we don't know yet.

• 36:51Neil deGrasse Tyson?

  But these five objects were those mysterious objects in the dark ages of the universe.

• 36:55Speaker 02

  Yeah, absolutely.

• 36:56Neil deGrasse Tyson?

  I think we did a thing on that. These were, there's a point where before galaxies formed.

• 37:01Speaker 02

  Right.

• 37:01Neil deGrasse Tyson?

  But matter had coalesced, so there's this gap, you know, before stars had formed, that we all just called the dark ages. And then James Webb turned on, found five galaxies doing the backstroke in the dark ages. Who ordered that? Nobody ordered that. Katie ordered that, apparently. Nice.

• 37:18Speaker 02

  Well, the other thing that's nice about this is the standard model, Lambda CDM, of cold dark matter and the dark energy that everybody considers the standard.

• 37:29Neil deGrasse Tyson?

  So CDM, cold dark matter.

• 37:30Speaker 02

  CDM, cold dark matter.

• 37:31Neil deGrasse Tyson?

  And Lambda is the, is Einstein's.

• 37:34Speaker 02

  Cosmological constant.

• 37:35Neil deGrasse Tyson?

  Which gives us the acceleration of the universe.

• 37:37Speaker 02

  Yes.

• 37:38Neil deGrasse Tyson?

  Yes, okay.

• 37:38Speaker 02

  So according to, according to that model, some of these, these objects they're seeing from the early universe are too massive. They'd have too many stars in them.

• 37:49Neil deGrasse Tyson?

  They didn't have time to make, to become that massive.

• 37:52Speaker 02

  Well, all of the, all of the ordinary matter of the universe would have had to go into these things, and that just doesn't make sense. You don't have enough ordinary matter to produce that many stars.

• 38:00Neil deGrasse Tyson?

  Hmm.

• 38:02Speaker 02

  So, all right, we'll take some. They're dark stars.

• 38:05Neil deGrasse Tyson?

  Ooh. Wow. Okay.

• 38:07Speaker 02

  Yeah, yeah. We don't know yet because you need, you need better spectra, you need more details.

• 38:12Neil deGrasse Tyson?

  But the rudimentary spectrum right now.

• 38:14Speaker 02

  The rudimentary spectrum, spectrum match.

• 38:17Neil deGrasse Tyson?

  And just to remind people, so you said, and I'm going to say it again, that when you take a spectrum, you want to know how much energy is coming in at different wavelengths. Right. And, and the shape of that spectrum is something, in principle, you can predict with your models.

• 38:31Speaker 02

  Yep, yeah.

• 38:31Neil deGrasse Tyson?

  And so if the spectrum matches up, so it's not just how much energy is here in this one spot, or how much energy is there, is what is the full? Once you have all these matched up, that's a pretty good prediction right there.

• 38:44Speaker 02

  Mm-hmm, mm-hmm.

• 38:45Neil deGrasse Tyson?

  It gives you some confidence. It's wild.

• 38:47Speaker 02

  So what we need in the future is to wait for more data, because some of those objects that are coming in are going to be lensed. In other words, there's a bunch of mass in front of them. It will magnify the images and then you're going to see in more detail and you'll be able to tell, oh, is that a dark star with exactly the hydrogen and helium that we predict? Or is it something else that has carbon, nitrogen, and so on? So, we're waiting for more data.

• 39:13Neil deGrasse Tyson?

  I have some memory that some people are calling, they have an idea called the dark big bang, is that a thing?

• 39:20Speaker 02

  Yeah, yeah, we invented that, I get to say it, we invented that.

• 39:23Neil deGrasse Tyson?

  Okay. Wow.

• 39:24Speaker 02

  Yeah.

• 39:25Neil deGrasse Tyson?

  Okay.

• 39:25Speaker 02

  Well, we were asking, we were realizing that people talk about, there was an inflationary epoch of accelerated expansion in the very early universe. And at the end of that, that energy, that the vacuum energy gets converted to ordinary stuff. And that's where ordinary matter would come from and people usually think, oh, you make matter, ordinary stuff, standard model particles, you make dark matter, you make it all at once. And we had the idea, well, wait a minute, what if you don't? What if the dark matter is produced later? And so, we're going to say, okay, there's inflation early on, but then there's a dark sector. Now, we're talking about dark matter that does not at all interact with ordinary matter, which is eh, you know, it's different.

• 40:11Speaker 02

  So, if in this dark sector, you could have a smaller vacuum energy that later on converts to dark matter, create the dark matter later, and the time that we were...

• 40:22Neil deGrasse Tyson?

  What does that buy you when you do that?

• 40:24Speaker 02

  Well, what we wanted to do was push it forward all the way to the time when matter and radiation, matter-radiation equality, in which case, that would be kind of cool that you're producing dark matter right then. But we were unable to do that, so the farthest forward we could push it is one month after the regular big bang. So, we have the dark big bang at one month, but that's human scale, which in the early universe is a really, really long time.

• 40:50Neil deGrasse Tyson?

  Given the sequence of events that unfolded... A zillion things happened before a month.

• 40:55Speaker 02

  Oh, God, yes.

• 40:56Neil deGrasse Tyson?

  Yes.

• 40:56Chuck Nice?

  Okay.

• 40:57Speaker 02

  And we also talked about what kind of dark matter particles you would get out. And so we have things like cannibal dark matter. We have dark zillas. We had a lot of fun.

• 41:05Neil deGrasse Tyson?

  Darkzilla.

• 41:06Speaker 02

  Dark, we have the dark wimps. All kinds of possibilities that are non-standard.

• 41:11Neil deGrasse Tyson?

  I never heard of these particles, but I don't want to mess with darkzilla.

• 41:14Speaker 02

  Well, darkzilla is pretty heavy, yeah.

• 41:16Chuck Nice?

  How about dark Rodan?

• 41:20Speaker 02

  The sculptor?

• 41:23Speaker 02

  Rodan?

• 41:23Neil deGrasse Tyson?

  No, no, no. Rodan, if you don't mention Godzilla, you gotta mention Rodan. Rodan was the.

• 41:28Chuck Nice?

  Art nemesis of Godzilla.

• 41:30Speaker 02

  He was?

• 41:31Chuck Nice?

  Yeah.

• 41:32Speaker 02

  Oh, I thought you were talking about the sculptor.

• 41:33Neil deGrasse Tyson?

  Yeah, so Rodan was basically a pterodactyl. But it was supersonic. So it would fly and like buses would tumble behind it. If darkzilla is this, has this huge mass and dark cannibal, what did you call it?

• 41:49Speaker 02

  Yeah, we have dark cannibals too.

• 41:50Neil deGrasse Tyson?

  Dark cannibals, what do those do?

• 41:52Speaker 02

  Dark cannibals eat, eat, eat themselves. So you start out with four of them and when they interact and you end up with only two of them.

• 42:02Chuck Nice?

  Ooh, man.

• 42:04Neil deGrasse Tyson?

  And two of them got bellies at the end and they.

• 42:11Neil deGrasse Tyson?

  Okay. So they don't just annihilate or anything, they actually consume them?

• 42:14Speaker 02

  Yes, they consume, they consume themselves.

• 42:16Neil deGrasse Tyson?

  And these are properties you have derived from all of your equations and your analysis?

• 42:19Speaker 02

  Well, these are different possible dark sector, dark matter particles that could come out of the dark big bang from these bubble collisions that people hadn't really thought about before. So these are, these are new ideas.

• 42:31Neil deGrasse Tyson?

  Okay, so there are people with other hypotheses that are out there, as there, of course there would be.

• 42:36Speaker 02

  Yeah.

• 42:36Neil deGrasse Tyson?

  Is there anyone who's specifically critiquing your work? Do you have a nemesis?

• 42:41Speaker 02

  No, I'm happy to say.

• 42:43Neil deGrasse Tyson?

  Good, that's good. So it's, so it is afloat with the other ideas and ultimately the data will, will, will show.

• 42:49Speaker 02

  Yes.

• 42:50Neil deGrasse Tyson?

  Excellent.

• 42:51Chuck Nice?

  So do you actually, as I'll ask you both, do you actually care if somebody, if, if their theory ends up proving out and yours does not? Does that, does that hurt at all?

• 43:05Speaker 02

  Of course.

• 43:06Chuck Nice?

  Okay.

• 43:06Speaker 02

  But I, I honestly think that dark stars.

• 43:11Speaker 02

  As precursors to black holes are better than the other candidates. Because I think the other, some of these other-

• 43:17Neil deGrasse Tyson?

  Says the person who came up with it. I'm just saying.

• 43:20Speaker 02

  True, true. So, but if, if one of those proves to be right, of course I'll be disappointed.

• 43:25Neil deGrasse Tyson?

  But, yeah, but, but I get to say as a non-participant in this exercise, in this research exercise, that if we have any solution at all, I'm celebrating.

• 43:39Speaker 02

  Yeah, okay, right, yeah, right.

• 43:41Neil deGrasse Tyson?

  Because it advances our understanding of the known universe.

• 43:43Speaker 02

  You know, there are people, actually it's the opposite. People have picked up on our ideas and there's a group in, in Sweden and jointly with University of Virginia, who have massive grant money to study dark stars as precursors for the supermassive black holes. And they're the ones who can give you the arguments why the other competing models have problems. And so it's, it's kind of the other way around. People are picking up on it.

• 44:09Chuck Nice?

  Right.

• 44:10Neil deGrasse Tyson?

  That's a good sign.

• 44:10Chuck Nice?

  That's a great sign.

• 44:11Neil deGrasse Tyson?

  Yeah, it's a good sign.

• 44:12Speaker 02

  Yeah, that is a good sign, yeah.

• 44:13Chuck Nice?

  And, and, and this is not something that you sought specifically to-

• 44:17Speaker 02

  No, no, not at all.

• 44:18Chuck Nice?

  This was just actually presented to you as you were seeking other information.

• 44:23Speaker 02

  Now, the, the, the, when, when we first came up with these ideas, we encountered massive resistance. So I remember going to when we, the, when we, the idea of dark stars-

• 44:32Neil deGrasse Tyson?

  Massive propagated by what particle?

• 44:35Chuck Nice?

  The macho, that was macho.

• 44:37Speaker 02

  Guys, guys, okay, human, humans-

• 44:40Neil deGrasse Tyson?

  Guys, human!

• 44:42Chuck Nice?

  The guy particle.

• 44:43Neil deGrasse Tyson?

  The guy particle?

• 44:44Chuck Nice?

  It's the guy particle.

• 44:45Speaker 02

  Guy particle.

• 44:46Chuck Nice?

  The guy-

• 44:47Neil deGrasse Tyson?

  Total hater. Yeah, and particle physics is like the last bastion of guy, of guidem.

• 44:52Chuck Nice?

  Right.

• 44:52Neil deGrasse Tyson?

  Right, okay.

• 44:53Speaker 02

  Yeah, so we went, we, we went to a conference and at Berkeley, one of the leaders in the field said, "This could radically revolutionize everything. Go to this conference and just put up a poster." Well, I didn't know how to make a poster, so we just put up a couple of pieces of paper and-

• 45:09Neil deGrasse Tyson?

  Just a poster at, at a conference, there are people who give talks, but there's not enough room for everyone, in time, to everyone give a talk. So they have poster sessions where you, and there's, there's drawbacks and benefits. Posters, you're not as visible.

• 45:22Chuck Nice?

  Right.

• 45:22Neil deGrasse Tyson?

  But you can have a one-on-one conversation with someone-

• 45:25Chuck Nice?

  Right.

• 45:25Neil deGrasse Tyson?

  That can be very enriching and deep.

• 45:27Chuck Nice?

  That's called a science fair.

• 45:28Neil deGrasse Tyson?

  Science fair.

• 45:30Speaker 02

  This is the only time in my life I've ever done a poster. I usually do talks. This was so new, there wasn't time to make a talk, right? And but people were extremely skeptical of the show, we say. I heard a grad student calling us crackpots. I'm not kidding.

• 45:46Neil deGrasse Tyson?

  Ooh.

• 45:47Speaker 02

  Yeah. And then that same grad student later ended up writing papers about it. So we had converts. That was really weird. And we had guys saying, why are you inventing wimps? Like, what? Why don't you use the Higgs for the dark matter? The Higgs lasts, huh, 10 to the minus how many seconds? You can't build dark matter out of it. So we had a lot of, a lot of contrariness, shall we say. So when you have a new idea.

• 46:09Neil deGrasse Tyson?

  Wait, you expect that for a new idea.

• 46:10Speaker 02

  That happens every damn time.

• 46:12Neil deGrasse Tyson?

  It's out of respect.

• 46:13Speaker 02

  Every time.

• 46:14Neil deGrasse Tyson?

  That they're attacking you.

• 46:15Speaker 02

  It was pretty, I was pretty shocked by these comments. But the same people, those two people, both ended up writing papers on dark stars independently.

• 46:24Neil deGrasse Tyson?

  That's satisfying.

• 46:25Speaker 02

  Well, I mean, if you have, you have, if you have your science.

• 46:28Neil deGrasse Tyson?

  Did they come back and apologize?

• 46:29Speaker 02

  No, but if you have your.

• 46:29Neil deGrasse Tyson?

  Okay, give me their name. Yeah. Chuck, we got a guy. We know who. We got a guy. Yeah, we got somebody.

• 46:34Speaker 02

  You got a guy?

• 46:35Neil deGrasse Tyson?

  We got somebody.

• 46:36Speaker 02

  Tell you later.

• 46:38Neil deGrasse Tyson?

  We'll talk. Yeah, we'll talk. Let us know.

• 46:40Speaker 02

  So that was, that's gratifying. If the science is right, people are gonna go, oh, okay. They'll, they'll catch on eventually.

• 46:46Neil deGrasse Tyson?

  Yeah, if the science is right.

• 46:48Speaker 02

  That was back in 2007.

• 46:50Neil deGrasse Tyson?

  Then they're just assholes, right? I mean, if the science is right.

• 46:52Speaker 02

  Yeah.

• 46:52Neil deGrasse Tyson?

  They're just, they're revealing that they can't even think outside their own box. Right.

• 46:57Speaker 02

  Right, so you go outside the box, you gotta expect this kind of stuff. And I've encountered it a lot, but in the end, if the science is right, then.

• 47:04Neil deGrasse Tyson?

  It's right, it's right.

• 47:04Speaker 02

  It's right.

• 47:05Neil deGrasse Tyson?

  Exactly. And if the science is right, it has nothing to do with how good a talk you gave.

• 47:10Speaker 02

  Yeah.

• 47:11Neil deGrasse Tyson?

  Or how, how we even paid it, it doesn't matter.

• 47:14Speaker 02

  You know, if you give good talks and people hear about what you're doing, that's important.

• 47:17Neil deGrasse Tyson?

  No, but that's so, but if the science is wrong. They'll hear about it and they'll just delay when it has to be put in the trash bin.

• 47:23Speaker 02

  True.

• 47:24Neil deGrasse Tyson?

  Right? Right, that's correct. Okay.

• 47:27Speaker 02

  So this goes back to the idea of, am I working? I can be creative, but is it sci-fi? No, because it has to, in the end, hold up both theoretically in terms of the mathematics and it has to not be ruled out immediately by some other bound that you didn't imagine. And, and so it has to hold up over the long term.

• 47:46Neil deGrasse Tyson?

  Yeah.

• 47:46Chuck Nice?

  Well, Katie, thanks for catching us up on this.

• 47:49Neil deGrasse Tyson?

  Yeah.

• 47:50Chuck Nice?

  I did not know all the latest. Who knew?

• 47:53Neil deGrasse Tyson?

  Dark.

• 47:53Chuck Nice?

  I mean.

• 47:54Neil deGrasse Tyson?

  To get dark. Dark universe. I know, I'm delighted to to learn that this remains an active, tested, hypothesized field.

• 48:06Speaker 02

  Yeah.

• 48:07Neil deGrasse Tyson?

  And and so should we forgive her for being a particle physicist and suggesting a particle as the result?

• 48:15Chuck Nice?

  Yeah, at this point, I'm I'm like the the student who wrote the paper.

• 48:21Neil deGrasse Tyson?

  You're a convert.

• 48:22Chuck Nice?

  I'm a convert.

• 48:22Neil deGrasse Tyson?

  Total convert.

• 48:23Chuck Nice?

  This is great.

• 48:24Neil deGrasse Tyson?

  Total convert. All in, all in. So Katie, thanks for coming.

• 48:29Speaker 02

  Thank you, Neil. Thank you, Chuck. Great to meet you.

• 48:32Chuck Nice?

  It's great to meet you, too.

• 48:32Neil deGrasse Tyson?

  You're based in Austin, but you came through town because, as you said offline, you presented at the World Science Festival.

• 48:39Speaker 02

  I did last Saturday.

• 48:40Neil deGrasse Tyson?

  Yes, and you know who runs the World Science Festival?

• 48:42Chuck Nice?

  Uh, Brian, right?

• 48:43Neil deGrasse Tyson?

  Brian Greene.

• 48:44Chuck Nice?

  Yeah.

• 48:44Neil deGrasse Tyson?

  He's a friend of our show.

• 48:46Speaker 02

  Yeah.

• 48:46Neil deGrasse Tyson?

  Yeah, and he brings together scientists and artists and the cultural forces just to show that science is a part of our everyday life. Does it every year. Might have had a COVID hiatus, but every year, and that brought you through town. And and your son is getting married.

• 49:00Speaker 02

  My son is getting married. Congratulations.

• 49:04Neil deGrasse Tyson?

  Okay.

• 49:04Chuck Nice?

  That's great.

• 49:05Neil deGrasse Tyson?

  You got it. All right, Katie, thanks for thanks again for coming through.

• 49:08Speaker 02

  Thank you.

• 49:09Neil deGrasse Tyson?

  All right, this has been StarTalk, the Dark Universe Edition, with my friend and colleague Katie Freese. Chuck, always good to have you.

• 49:19Chuck Nice?

  Always a pleasure.

• 49:20Neil deGrasse Tyson?

  Unlike so many other exploits in our civilization, science is exquisitely tuned with its methods and tools to establish that which is objectively true and discard that which is objectively false. And we accomplish this by putting forth an idea and testing it, challenging it, attacking it even. Because there's so many ideas, there's so many ways the universe could be.

• 49:56Neil deGrasse Tyson?

  But there's only really one way that it is. So that ultimately, no matter what ideas you have, no matter how you think the universe can be, should be, ought to be, it is the ultimate judge, jury, and executioner of any thoughts you have. And to chat with Katie, friend and colleague, from the particle physics universe, about how they take known ideas about the universe that have been tested, and then extend them into realms that are not yet tested, I'm just reminded about not only how science works,

• 50:37Neil deGrasse Tyson?

  but how beautiful it is when it makes discoveries derived from it. That is a cosmic perspective. Till next time, keep looking up.