
What are the main candidates for dark matter? Neil deGrasse Tyson and comic co-host Chuck Nice sit down with theoretical physicist Katherine Freese to tackle fan questions about dark matter, dark energy, and the dark universe at large.
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Chuck Nice
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Neil deGrasse Tyson
Today we are growing our stable of cosmologists.
Chuck Nice
Yes.
Neil deGrasse Tyson
Got Katie Freeze coming in.
Chuck Nice
That's right.
Neil deGrasse Tyson
Talks about dark matter, dark energy. Rockin'.
Chuck Nice
Yep. The only cosmologist who sounds like a Batman villain, Katie Freese.
Neil deGrasse Tyson
Coming up on StarTalk. Welcome to StarTalk, your place in the universe where science and pop culture collide. StarTalk begins right now. This is StarTalk. Neil DeGrasse Tyson, your personal astrophysicist. This is gonna be a cosmic Queries edition on cosmology. There's no end of cosmic queries we can do on cosmology.
Chuck Nice
I suppose there is not.
Neil deGrasse Tyson
This is Chuck Nice right here.
Chuck Nice
That's right.
Neil deGrasse Tyson
Professional comedian. Stand up comedian.
Chuck Nice
There is an end to me.
Neil deGrasse Tyson
So cosmology. Yes. So we're broadening our stable of cosmologists to whom we can reach out for Our queries. Right. And today we have a second timer.
Chuck Nice
That's right.
Neil deGrasse Tyson
The one and only Katie. Freeze. Katie.
Chuck Nice
Welcome back.
Katie Freese
Yay.
Neil deGrasse Tyson
Welcome back to StarTalk.
Katie Freese
Thank you. Thank you.
Neil deGrasse Tyson
Last time you were here, I think we talked about the search for dark matter. And we did. We did.
Katie Freese
We did.
Neil deGrasse Tyson
Because that's cosmology writ large. And we poked your brain about all manner of things. And this is gonna be a cosmic queries where we have told our Patreon supporters that you're gonna be on and they're fans of yours and they've written in. Or they became fans of yours when they saw your expertise.
Chuck Nice
That's right.
Neil deGrasse Tyson
And they wrote in. And the questions are here.
Katie Freese
Well, thanks a lot. I haven't seen these queries.
Neil deGrasse Tyson
Well, neither have I. He's the only one who's seen them.
Chuck Nice
Yes.
Neil deGrasse Tyson
Okay.
Chuck Nice
And I'm the only one who can't answer them.
Katie Freese
That may be true.
Neil deGrasse Tyson
That is kind of funny. The only people who can answer them haven't seen it. And the one who can't answer.
Chuck Nice
There you have it. So
Neil deGrasse Tyson
a couple of times people have asked questions that no one has been able to answer. Like with the quark one going into a black hole.
Chuck Nice
Quark into a black hole. We still don't know the deal.
Neil deGrasse Tyson
We still don't know that one.
Chuck Nice
Everybody's.
Neil deGrasse Tyson
Maybe Katie knows. We can find out.
Chuck Nice
We should find out. Yeah.
Neil deGrasse Tyson
Well, let me get your bio here. Director of the Weinberg Institute for Theoretical Physics, UT Austin. That's Stevie Wonder. Steven Weinberg.
Chuck Nice
Yeah.
Neil deGrasse Tyson
Right.
Katie Freese
So Steve Weinberg, my hero. One of the founders of the standard model of particle physics.
Neil deGrasse Tyson
Yes.
Katie Freese
He was the greatest physicist of our time. In the opinion of many, including me. His office was three doors down from me. He recruited me to UT Austin. Maybe that's why I think he's the greatest lightning physicist.
Neil deGrasse Tyson
That helps. Who gave you the good job, right?
Katie Freese
Right.
Neil deGrasse Tyson
Yeah, but it was only named.
Katie Freese
No, seriously.
Neil deGrasse Tyson
He was only named in his death, obviously.
Katie Freese
Yeah, he died about three years ago.
Neil deGrasse Tyson
Yeah. Okay.
Katie Freese
And we started the institute in his honor.
Neil deGrasse Tyson
And now he's more a hero for me than he is for you.
Katie Freese
Why is that?
Neil deGrasse Tyson
Cause he went to my high school.
Chuck Nice
Oh, Bada bing.
Katie Freese
Oh, Bronx Science.
Neil deGrasse Tyson
The Bronx High School of Science.
Katie Freese
Yeah, yeah, yeah.
Neil deGrasse Tyson
Both he and Shelly Glashow were in the same class. They were classmates and both shared the Nobel Prize.
Katie Freese
Okay, so the moral of the story is, when are you getting your Nobel Prize?
Neil deGrasse Tyson
Yeah. I didn't mean to set it up that way. That was not. So what else do I have here? And you spent some time at Stockholm University. And that's ending coming up very shortly.
Katie Freese
10 years. They gave me a really. The Swedish government gave me a $15 million grant over 10 years to do cosmoparticle theory. And that was so much fun.
Neil deGrasse Tyson
Wow.
Katie Freese
Oh, wow.
Neil deGrasse Tyson
Did you have students too and everything?
Katie Freese
Oh, I did.
Neil deGrasse Tyson
With a budget to go back.
Katie Freese
I did, yeah. So I had students and I had postgraduate fellows and everybody running up and down the halls having great ideas and having fun. It was awesome.
Neil deGrasse Tyson
Wow.
Katie Freese
Ye.
Neil deGrasse Tyson
Okay. Because I think when we last interviewed you, you were like fully up and running with them. And what else? Oh, and I'd love this back now 10 years ago. The Cosmic Cocktail. Can you get a better title than that?
Chuck Nice
Shaking Nuts.
Neil deGrasse Tyson
I don't. I don't think. Three parts dark Matter. Ooh, that's about right.
Chuck Nice
That's pretty cool, man.
Katie Freese
You know, the amazing thing about that book is that I still give public lectures about it and people are still buying lots of them. In fact, Amazon ran out again.
Neil deGrasse Tyson
Whoa.
Katie Freese
And that was a book I wrote 10 years ago. So. Good for you, I guess. It was a good one. And you wrote a blurb for it. You said. What did you say? I don't know, three parts dark matter, seven parts memoir or something like that. Oh, right.
Neil deGrasse Tyson
Because it was folded into your life.
Katie Freese
It was, yes.
Neil deGrasse Tyson
Very important feature of that. Thanks for reminding me. It just made it a much more interesting account. Yeah, right, right. Cool. Here's another plug for it.
Katie Freese
Thank you.
Neil deGrasse Tyson
Amazon run again. So we're going to chat for a bit before we go to Q and A to catch us up on a couple of things. The James Webb. There's been a lot of talk about these early galaxies that it has discovered in a zone of the early universe where you're not supposed to.
Katie Freese
So wait, you're talking about the James Webb Space Telescope?
Neil deGrasse Tyson
Yeah, yeah. Not the administrator of NASA during the 1960s after whom the telescope was named. You know, he was an accountant.
Chuck Nice
James Webb. Yeah, I did.
Neil deGrasse Tyson
One of the rare non scientists after whom a telescope is named.
Chuck Nice
An accountant.
Neil deGrasse Tyson
I think that was his main training.
Chuck Nice
That's pretty wild, I gotta say.
Katie Freese
I guess he was. What was he important for in NASA?
Neil deGrasse Tyson
He was head of NASA.
Chuck Nice
Was the head of hr Taken while
Neil deGrasse Tyson
we went to the moon. He was head of NASA. So it was. Give a little back to that. Look at that fact. Cause you need to. You need good administrators, not just good scientists to make stuff happen. When you're in bureaucracy.
Chuck Nice
Well, you're a damn good administrator. When they start naming Stuff. After you.
Neil deGrasse Tyson
So what's this we hear about paleo detectors? What is that? Is that a thing?
Katie Freese
Yeah.
Neil deGrasse Tyson
What is that?
Katie Freese
Well, the paleo part means that they've been around for a billion years. And so these. Let me back up. We're trying to figure out what dark matter is made of.
Neil deGrasse Tyson
Yes.
Katie Freese
And we think it's some kind of particle we haven't identified yet.
Neil deGrasse Tyson
Yes.
Katie Freese
And most of the experiments now involve these giant tons and tons of liquid xenon. And so the idea is, okay, instead of having.
Neil deGrasse Tyson
That's because xenon has some probability of interacting with a dark matter particle.
Katie Freese
Yeah, yeah. Dark matter particles flying around in the galaxy. And by the way, there would be billions going through your body every second. Yeah, yeah. But it's okay. Only one a month hits you.
Chuck Nice
I thought I felt tired for a reason.
Neil deGrasse Tyson
You know, there's a lot of elements on the periodic table. Why do you know that xenon might work when we otherwise know nothing about dark matter?
Katie Freese
The way these detectors work is the dark matter comes along, hits one of these xenon atoms, deflects off of it, and the xenon gets some energy deposited in it, and they're able to detect that. So there's. You have to have a detector design that works. And with xenon, we know how to do it.
Neil deGrasse Tyson
Okay. So it could be any particle that that would happen to. But xenon has some other convenient properties.
Katie Freese
So the kind of interactions we're looking for is from the weak force, very, very weakly interacting particles.
Neil deGrasse Tyson
Hence the name.
Katie Freese
Hence the name. Weakly interacting massive particles. And people need to build detectors that are. That they know. You need to know how to build a damn detector. I don't know how to answer this one, Neil.
Neil deGrasse Tyson
No, so say it differently. A neutrino detector, for example, that uses vats of liquid, uses like some kind of chlorine molecule, but not xenon. So where are these xenon detectors?
Katie Freese
They're deep underground.
Neil deGrasse Tyson
Okay.
Katie Freese
One of them is underneath the Apennine Mountains outside of Rome. Okay. Ooh.
Neil deGrasse Tyson
You know the Apennine Mountains on the moon named after those.
Chuck Nice
I was gonna say that. You've actually said that Italy came first named after the mountains here.
Neil deGrasse Tyson
The reason why I know them and the reason why they are is the phase of the moon that's best for telescopic views is half moon.
Chuck Nice
Okay.
Neil deGrasse Tyson
Cause shadows are the longest. And the Apennine Mountains crosses the half moon divider, the terminator. And so Apennines just pop on a first sighting of the moon. Oh, so to me, the Apennine Mountains are on the moon, not in Italy.
Katie Freese
All right.
Neil deGrasse Tyson
Okay.
Katie Freese
Well, if you could build something on the moon, that would be even better, because the reason you have to go underground is to get away from cosmic rays.
Neil deGrasse Tyson
Okay?
Chuck Nice
Right.
Katie Freese
And there's a million cosmic rays for every one of these dark matter particles if you're on the surface of the Earth. So we go deep underground because the cosmic rays don't make it down there.
Neil deGrasse Tyson
But the dark matter particle would.
Katie Freese
But the dark matter particles would.
Neil deGrasse Tyson
Okay. Based on what we think dark matter particles would be like.
Katie Freese
Well, because they're only weakly interacting.
Neil deGrasse Tyson
Okay. Normal particles would interact electromagnetically.
Katie Freese
If you and I collide, we're not getting very far.
Neil deGrasse Tyson
No, that's right, because we don't pass through.
Katie Freese
We don't pass through each other.
Neil deGrasse Tyson
Right.
Chuck Nice
I'll tell you something about xenon. Makes a hell of a headlight. Just wanted to contribute something.
Neil deGrasse Tyson
I don't know.
Katie Freese
I'll tell you. Want to hear another something about xenon? Another thing about xenon, it's become very expensive because the xenon experiments have bought the entire world supply.
Neil deGrasse Tyson
Get out.
Katie Freese
No, I'm serious.
Neil deGrasse Tyson
Wow.
Chuck Nice
Wow. I wish.
Katie Freese
I'm serious.
Chuck Nice
Now you tell us.
Neil deGrasse Tyson
Yeah, you should have told us.
Chuck Nice
You told us before these experiments. We could have got it on the cornering of the xenon market.
Katie Freese
Oh, my God, that's true.
Neil deGrasse Tyson
Yeah.
Katie Freese
Which is why we want to propose an alternative. So instead of giant detectors, we're going to dig up little rocks from deep underground, and they've been collecting dark matter tracks for a billion years, so we're replacing volume with time. Isn't that cool? Hence paleo.
Chuck Nice
Oh, okay. Now that is. First of all. That's very smart. Thank you. Yeah.
Neil deGrasse Tyson
Wait, wait. So how do you know which rock to get? Or any rock?
Katie Freese
Oh, well, we had to talk to a lot of geologists, and, you know, this was first a paper with a few theorists in 2018, and next thing you know.
Neil deGrasse Tyson
So in 2018, that was only a proposal.
Katie Freese
It was.
Neil deGrasse Tyson
Yeah.
Katie Freese
We wrote a bunch of theory papers. Not every day does this stuff turn into reality. I've done it twice now. You know, the underground detectors? I wrote papers that got that going. And now with Paleo detectors, that's actually becoming a major experimental effort. Isn't that cool?
Neil deGrasse Tyson
And it's a cool name for a detector, too. Yeah. So they tell you which rocks would
Katie Freese
best respond to this, and the answer is Olivine.
Chuck Nice
Ooh, olivine.
Katie Freese
Olivine.
Neil deGrasse Tyson
I know. Olivine.
Katie Freese
You Do?
Neil deGrasse Tyson
Yes.
Katie Freese
Okay.
Neil deGrasse Tyson
There's a class of meteorite called pallasites. Where? Oh, my gosh. So where do you get a meteorite from? It's a smashed whatever it used to be. Right. Okay. So if it's a protoplanet, it meant it partially, as the geologists would say, differentiated, because at some point in its formation, the heavy stuff would fall to the middle, the lighter stuff would float to the top. If, however, it cools before it fully segregates, then the metallic innards can trap olivine crystals.
Katie Freese
Oh, wow.
Neil deGrasse Tyson
Within it as they were slowly bubbling their way up to the top. And so a slice of these meteorites rear lit, if it's thin enough, the thickness of an olivine crystal. You see the metallic meteorite and these green crystals going through. And we have a sample of one in our whole of the universe.
Katie Freese
Oh, very cool.
Neil deGrasse Tyson
It's called a pallasite.
Katie Freese
Oh, I gotta see this.
Neil deGrasse Tyson
I'll take you down right after this.
Chuck Nice
Very cool, very cool.
Neil deGrasse Tyson
So in other words, it's rare because the boundary layer between the dense middle of a protoplanet and the lighter things that float up is very thin. And so when you smash the whole thing, you have a lot of rocky stuff, less metallic stuff, and even less at the boundary layer.
Katie Freese
Well, can we borrow your olivine to look for dark matter tracks, please?
Neil deGrasse Tyson
You gotta know somebody.
Sponsor/Ad Voice
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Neil deGrasse Tyson
You gotta know somebody who works here.
Katie Freese
Thought I did.
Neil deGrasse Tyson
Yeah. No, we can totally. We can totally explore them. That could be the key. Sitting under our noses. But it's been here for 25 years.
Katie Freese
Well, then it's been collecting cosmic ray tracks.
Chuck Nice
Oh, yeah.
Neil deGrasse Tyson
No, it's. We didn't have it.
Katie Freese
Sad.
Chuck Nice
Yeah. Do you guys have any, like, deep under the Earth here? Like, is there a secret?
Neil deGrasse Tyson
But it still has to get through the building.
Katie Freese
We want to know about the sub basement.
Neil deGrasse Tyson
Get through the building, though. The cosmic rays have to get through the building.
Katie Freese
Yeah.
Neil deGrasse Tyson
Well, that'll block some of them, right?
Katie Freese
Nah.
Neil deGrasse Tyson
All right, so congratulations on this. This is now a burgeoning next step in this. So why a billion years and not 100 million or 50 million? Does it matter?
Katie Freese
Well, we have to go deep enough to get away from cosmic rays, and that's actually like five kilometers.
Neil deGrasse Tyson
Oh, that's deep.
Katie Freese
And then the other idea is if we get rocks from different ages, we also can study neutrinos, because neutrinos will also leave tracks. The tracks will be different. Okay. So you can tell the difference, but then you can figure out how many supernova went off in the galaxy, if you look in the past, a different amount of time. Isn't that cool?
Chuck Nice
Wow, man. And that is because the supernova, that's where the neutrinos come from.
Neil deGrasse Tyson
Copious immunity.
Katie Freese
Oh, I forgot to say that.
Neil deGrasse Tyson
Yeah.
Katie Freese
Neutrinos give off a lot of supernova. No,
Neil deGrasse Tyson
no, no, no.
Katie Freese
Supernova give off a lot of neutrinos. And so you. Which supernova which are dying exploding stars. And you can look for the neutrinos from the supernovae.
Chuck Nice
Right. Cool, man.
Neil deGrasse Tyson
And neutrinos are once again your weakly interacting particles.
Katie Freese
Yeah, they are also weakly interacting particles.
Neil deGrasse Tyson
Yeah.
Chuck Nice
Most unfortunate particles.
Katie Freese
Now the other thing you can do
Neil deGrasse Tyson
with weakly intermeching particles.
Katie Freese
Yeah, well, we know who named them that.
Chuck Nice
New names.
Neil deGrasse Tyson
Have I forgotten?
Katie Freese
Mike Turner.
Neil deGrasse Tyson
Is that right? Mike Turner.
Chuck Nice
That would have made sense if you said I Turner.
Neil deGrasse Tyson
Whoa.
Katie Freese
The word eponymous comes to mind.
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Chuck Nice
Nicholas I'm Nicholas Costella and I'm a
Katie Freese
proud supporter of StarTalk on Patreon.
Chuck Nice
This is StarTalk with Neil DeGrasse Tyson.
Neil deGrasse Tyson
So I got one more question before we go to Q and A. Some of the results of the James Webb Space Telescope and other sources suggest that we cannot reconcile the age we have derived for the universe by these different methods. One of them is from the CMB cosmic microwave background. Others is from galaxies at other times. And it has been suggested that you can reconcile them if dark energy changes over time.
Katie Freese
The biggest evidence for dark energy changing over time comes from a different experiment, the DESI experiment.
Neil deGrasse Tyson
Okay.
Katie Freese
And what they're looking at, Lucy and desi,
Chuck Nice
dark matter. You got some splinter to do. Oh, that's good.
Katie Freese
That's good.
Neil deGrasse Tyson
With desi. So other than Lucy and desi, what does DESI stand for? Astrophysically?
Katie Freese
The Dark Energy Spectroscopic Instrument.
Neil deGrasse Tyson
Okay. All right. Clean and simple. And what does that tell us?
Katie Freese
What they're looking at is based on some physics from the early universe. And there were waves which froze out at the same time the cosmic microwave background was produced. So that's 400,000 years after the Big Bang, which is like, I don't know, a thousandth of a percent of the age of the universe today. And what those waves did was leave an imprint that throughout the rest of time, galaxies form in these spheres left over from those waves. And so as time goes on, you look at how big are those spheres, and that tells you about the expansion of the universe.
Neil deGrasse Tyson
Yes.
Katie Freese
And what they're saying is because the
Neil deGrasse Tyson
spheres would grow with the universe.
Katie Freese
Yeah.
Neil deGrasse Tyson
Yes.
Katie Freese
Yeah. And so by studying that, you can figure out what the expansion is doing. Is it accelerating? What is it doing? And what they claim is that the dark energy, which everybody, the vanilla model, is that it doesn't change in time, but it definitely affects the overall Expansion of the universe. No matter what it's causing the acceleration. So we think. And what they're claiming is that the acceleration is slowing down. Oh, so it's a decrease in the dark energy contribution to the universe. So now can I put it in a plug for my own work, please? So my collaborator Yun Wang and I, we looked at the same data, and we looked at it differently with a simpler way of interpreting the data. And we do not find that evidence to be very strong, actually. So I don't think it's happening. Big picture, There's a big debate. Is it real? Is the dark energy changing with time or not? Is it time varying or not? And different people have different opinions on the point.
Neil deGrasse Tyson
If you found a simpler way to look at it, where the effect goes away, and we were betting on the likelihood of one truth or another, I'm betting with a simpler explanation.
Katie Freese
Thank you. Well, me too, obviously.
Neil deGrasse Tyson
I mean, that taps Occam's razor.
Katie Freese
Well, from the data, we're directly extracting the dark energy density, the amount of dark energy, instead of going through a secondary. A secondary thing, which is called the dark energy equation of state. So we're doing it more directly. So that's why I like what we're doing better.
Neil deGrasse Tyson
So you know about Occam's razor. You've heard.
Chuck Nice
Let me just think. Removing all other considerations, the simplest answer is the most likely.
Neil deGrasse Tyson
That's a modern interpretation. What he actually said was, go ahead. Multiplicity ought not be posited without necessity.
Chuck Nice
Oh, wow. Wow. Damn.
Neil deGrasse Tyson
So Occam, named for William of Ockham, he goes way back.
Chuck Nice
Okay.
Neil deGrasse Tyson
Yeah, like 700 years. Wow. So he had some insights into nature that persists to this day.
Chuck Nice
William of Ockham, sure enough, he knows how to turn a phrase, that's for sure.
Neil deGrasse Tyson
So I'm betting on Katie on this one. Definitely. Very cool. But let me exit this before we get to the questions with a related question.
Katie Freese
Okay.
Neil deGrasse Tyson
You said the vanilla version of dark energy is that it does not change over time.
Katie Freese
Yeah.
Neil deGrasse Tyson
That's how it appears in Einstein's general relativity.
Katie Freese
It is a constant, the cosmological constant.
Chuck Nice
Right.
Neil deGrasse Tyson
If you want to start making that not constant, then it's no longer Einstein's general theory of relativity. It's some modification to it.
Katie Freese
No, it doesn't.
Neil deGrasse Tyson
How does he accommodate. How can his formulation of general relativity accommodate a cosmological constant that's not constant?
Katie Freese
I just want to say about dark energy, it is a complete mystery to all of us. We have no idea what's going on, to be honest. Okay. We could call it gobbledygook.
Neil deGrasse Tyson
I've already named it Dark matter and dark energy. Are Fred and Wilma okay? Cause it doesn't have any bias at all. They're just two words.
Katie Freese
Well, I don't know, because we know dark matter exists. I'm not so sure about dark energy. I want Wilma to exist. But anyway, but so dark energy, there's two possibilities. One is, as you said, you have to modify Einstein's equations and that feels wrong to me. Well, you know, I actually had an idea for how to do that 2002, but let's not go there. I want to talk about the other way, which is we stick with Einstein's.
Neil deGrasse Tyson
Wait, in 2002 you had a way to modify Einstein's general theory of relativity.
Katie Freese
Well, more specifically the evolution equation for the universe. Yeah, the Friedman equation for the universe. We had been working in extra dimensions. If you have string theory.
Neil deGrasse Tyson
As one would do.
Katie Freese
As one would do. Because as one does. As one does. So in string theory you have to have 10 spatial dimensions instead of the X, Y, Z, the normal ones that we usually work with. And if you do that, it's possible that, well, our universe is a three dimensional surface in there and there could be another one and the stuff in between, which we call the bulk is pulling on our surface and causing the equations to change.
Chuck Nice
Oh, interesting.
Katie Freese
So we positively.
Neil deGrasse Tyson
Okay, so the equations would be sound within the universe left to its own devices, but influence outside of it. You gotta give it some slack.
Katie Freese
Yeah, you do. You gotta add these other terms into the equations which describe the evolution of our three dimensional universe.
Neil deGrasse Tyson
She just called our universe a slice.
Katie Freese
I did, yeah. I believe that it's kind of an interesting slice. I like it.
Neil deGrasse Tyson
Yeah, it's a dimensional slice. Yeah, that's a dig if I ever heard one.
Chuck Nice
I don't know, like during my Ayahuasca trip, I met some beings that told me that there were dimensions alongside of our dimension, like more than we could ever know. Dimension, dimension, dimension. And that there were dimensions above and dimensions below. I don't want. Anyway, I don't even know why I said this. Let's.
Katie Freese
But, yeah, but you know what they're called in, in physics? They're called brains. B, R, A, N, E. Okay.
Neil deGrasse Tyson
Which is short for membrane.
Chuck Nice
Membrane, yeah, short for membrane. Just like. Yeah, yeah, yeah. So they're like thin little dividers.
Katie Freese
So the question you're asking, do some other of these brains contain B, R, A, I, N's? And we don't Know.
Neil deGrasse Tyson
Because we know ours does, right?
Chuck Nice
I mean, I think so keep telling yourself, if you want to call it
Neil deGrasse Tyson
that,
Chuck Nice
we use the term loosely in our dimension.
Katie Freese
So on the. Can I tell you what I called this theory?
Neil deGrasse Tyson
What?
Katie Freese
I called it Cardassian cosmology. And the reason is that Lisa Randall was going on about the warp factor,
Neil deGrasse Tyson
which I thought there's another physicist up at Harvard.
Katie Freese
Oh, yeah, she's great. And so she was talking about the warp factor in her theory and I thought that came from Star Trek, but actually it's just a relativity term that I had heard called something else. And so I thought, well, I'm going to go to Star Trek. So I went for the Cardassians. So I called it Cardassian expansion because everything would be made of ordinary matter, ordinary radiation, ordinary stuff, no weird dark energy, but the equations would be different. And so like the Cardassians, they are. They're weird looking, but they're made of the same. But they're two bipeds like we are, and their goal is accelerated expansion of their evil empire.
Chuck Nice
Correct? That's right. They're quite draconian and their whole purpose is to take over everything.
Katie Freese
Yeah, well, Kardashian.
Chuck Nice
Yes. The Cardassians. Yeah, yeah, yeah.
Neil deGrasse Tyson
Well, all right, so you got questions, we got.
Chuck Nice
Let's get to it. Let's jump right in. These are directly for.
Neil deGrasse Tyson
And you haven't seen these questions?
Katie Freese
No. That's not fair.
Chuck Nice
Why do you know?
Neil deGrasse Tyson
I don't know. That's the whole thing here.
Chuck Nice
All right, well, this first question is from anthropocosmic Dylan, who basically says, hey, yeah, he says, how do dark stars work? What would they be like to visit? And how do they impact extrasolar systems and potentially astrobiology? So he's just. He wants you to just answer everything.
Neil deGrasse Tyson
That's where it all happens. Let me prepend that.
Chuck Nice
Go ahead in.
Neil deGrasse Tyson
Was it the 1800s or late 1700s? There was a calculation done by a physicist who said to himself, the gravity on a star is whatever it is, but if the star shrinks, the surface gravity goes up. There'll be a point where the surface gravity prevents light from escaping and the star will disappear from the universe.
Katie Freese
In other words, what we call now black holes.
Neil deGrasse Tyson
Exactly. So it was like the first attempt at thinking about what we now would call a black hole, but so that technically would be a dark star. But I don't think that's what this question is about. I think they're asking if matter can make planets, can dark matter make planets?
Chuck Nice
No.
Katie Freese
I mean, I think he's asking about my work on dark stars.
Chuck Nice
Oh.
Katie Freese
And dark stars are not made of dark matter. They're the first stars that form. And they would be made of ordinary stuff, ordinary hydrogen, ordinary helium, almost entirely. But they're powered by the dark matter that's inside them. But just so it's ordinary matter powered by dark matter.
Neil deGrasse Tyson
It's one of your early papers.
Katie Freese
Instead of by, there's no fusion. It's dark matter power.
Chuck Nice
Wow.
Katie Freese
Yeah.
Neil deGrasse Tyson
That's some crazy innovation.
Katie Freese
If they exist, these things. I'm so excited because we have candidates for them in the James Webb Space Telescope. I'm so excited. They would start out at about the same mass as the sun, but then they would grow, grow, grow until they become a million times as massive as the sun and a billion times as bright.
Neil deGrasse Tyson
They grow because they're absorbing dark matter?
Katie Freese
No, because they're absorbing ordinary matter. Normal stars can't keep growing because their surfaces are hot. You know, they have fusion. Fusion's hot.
Neil deGrasse Tyson
Right.
Katie Freese
And then so they blow stuff off. But dark stars are cool. Oh. In radius, they're 10 times the distance between the Earth and the sun.
Neil deGrasse Tyson
So they're huge.
Katie Freese
They're huge and they're cool. Which means they can keep accreting matter. Grow, grow, grow, and they get really, really big.
Neil deGrasse Tyson
So there's no pressure on the outer surface to prevent new matter from accreting to it.
Katie Freese
Yeah, exactly. Exactly.
Chuck Nice
Right.
Katie Freese
So they can get really big. And we have candidates in the James Webb Space Telescope for some of those really early objects that are super bright and they don't know how to explain them. Well, we'll take them.
Neil deGrasse Tyson
You'll take them?
Katie Freese
We'll take them.
Chuck Nice
Whoa. Yeah.
Katie Freese
I'm excited.
Neil deGrasse Tyson
When you win your Nobel Prize, will you come back and on their show.
Chuck Nice
Was that a kiss?
Neil deGrasse Tyson
No.
Chuck Nice
Okay.
Neil deGrasse Tyson
The body language, that was a very, very, like, gesture. No, he's. He's still learning social cues. Oh.
Katie Freese
I'm at the opposite.
Chuck Nice
Okay, cool. Yeah. I'll tell you this much. Once. Once you. He's right. That is Nobel stuff right there, man. That's fantastic.
Katie Freese
So the, you know, the thing about astronomy field is that you can have a great idea and. You know. Let me back up. Usually when you have a great idea, you kill it in 10 minutes because it violates some observation. Occasionally it not only survives those first 10 minutes, but then people start telling you, did you know you solved this problem? Did you know you solved that problem? And that's what's going on here.
Neil deGrasse Tyson
Yeah, that's right.
Katie Freese
We keep Solving problems. So dark stars could explain a lot of things that could explain, once they die, the supermassive black hole that you see in the early universe. They could explain the blue monsters, and they could explain the little red dots. And I figured you'd like those terms.
Neil deGrasse Tyson
Whoa. They're very bluntly descriptive of stuff we see in the early universe because there's nothing nearby that we have a counterpart to. It's a red dot. It's a red dot.
Chuck Nice
Okay, so we call it a red dot. Now, what about the blue monster? Where'd you get that reference?
Katie Freese
Blue monster is a really, really, really bright objects way early in the history of the universe.
Neil deGrasse Tyson
Yeah, it should be like the formation of galaxies. I mean, we know they're blue. They don't look blue. They look very infrared. Cause that blue has been redshifted to the sweet spot of the James Webb telescope.
Chuck Nice
Yeah, yeah, but. Yeah, that's very cool. All right. Okay. Well, hey, what a great question. Anthropogenic.
Neil deGrasse Tyson
So she said she's coming back after her Nobel prize. Absolutely.
Chuck Nice
Now here's the question. Can I wear your Nobel prize when you come back?
Neil deGrasse Tyson
So here's the best line related to that. It was from Hoop Dreams. Do you know the line?
Chuck Nice
I don't know. I don't know the movie.
Neil deGrasse Tyson
You know this line? You know the movie?
Chuck Nice
I don't think I know. Hoop Dreams.
Neil deGrasse Tyson
Hoop Dreams. Go ahead, dude. There's a documentary.
Katie Freese
Oh, you don't know Hoop Dreams?
Chuck Nice
I do not know Hoop Dreams, but go ahead.
Neil deGrasse Tyson
Yeah, it's a documentary following high school students, some who have ambitions to play in the NBA.
Chuck Nice
Oh, okay, okay.
Neil deGrasse Tyson
And the social dynamic that surrounds it. It's a documentary, but here's the line. When you're rich and famous, will you remember us? As one of them goes off and he says, if I'm not rich and famous, will you remember me?
Katie Freese
Damn. Oh, that's good.
Neil deGrasse Tyson
That's good.
Katie Freese
That's really good.
Chuck Nice
I'll tell you, the answer to both those questions is Ouch. No. The answer no to both. All right, let's move on. This is Nate, and Nate says hello, Dr. Tyson, Dr. Freeze and Lord. Nice. This is Nate from Southern Idaho. If dark energy has gravitational effects on everything, just like regular matter does, why does it not coalesce and push away from itself? This seems counterintuitive considering the fundamental nature of gravity is to pull things together by bending space time. Does dark energy abide by its own rules where it can cause gravity, but it isn't affected by it? This would imply that it is not influenced by the curvature of space time in which it causes. This guy did some thinking here. Freaking Nate, bro.
Neil deGrasse Tyson
Whoa, dude. Whoa. So let's start from scratch.
Chuck Nice
Yeah.
Neil deGrasse Tyson
We're calling it dark energy because it's a placeholder term. We don't know what the hell it is.
Katie Freese
Right.
Neil deGrasse Tyson
But if it's energy at all, then it has a mass equivalent and it should have gravity. So does dark energy have gravity?
Katie Freese
The definition of matter is that it feels gravitational attraction. So that's true for ordinary matter. That would be you and me and you.
Chuck Nice
I was gonna say. Thanks.
Neil deGrasse Tyson
He's not ordinary matter.
Katie Freese
He's not ordinary matter. And it would be dark matter. So all of that stuff clumps together,
Neil deGrasse Tyson
is attracted together, and energy contains a matter equivalent.
Katie Freese
No, no. You know, for ordinary matter and energy, that is true, but for dark energy, it is completely different from matter. It is something that's causing a repulsive behavior. It's pushing things apart from one another.
Neil deGrasse Tyson
That's why we should call it just Wilma. Something that doesn't have the word energy in it.
Katie Freese
Yeah. Yeah. So it's not. So it's confusing because matter and energy in the ordinary world are related, but dark matter and dark energy are probably not.
Neil deGrasse Tyson
Okay, so the foundation of this question is not valid because it's assuming that it's participating in the curvature of space time. And if it's helping to make it, why isn't it responding to it? Why is it spreading things out rather than pulling things in?
Katie Freese
Well, I mean, it does fit into Einstein's theory of general relativity. It's just that if you have this vacuum energy, it causes repulsion rather than attraction. It causes acceleration. So it's a completely different type of.
Neil deGrasse Tyson
Yeah, but we calculated with that. And you're off BY like, oh, 10
Katie Freese
to the 120 power. Yeah. In the exponent.
Neil deGrasse Tyson
Yeah, that's true. Yeah.
Katie Freese
Well, I'm not saying we understand it. I'm not saying we can calculate it.
Chuck Nice
That's funny.
Neil deGrasse Tyson
Isn't that the biggest mismatch between a theory and a calculation ever?
Katie Freese
Yeah, it's really. It's just unbelievable. Vacuum energy. What does that mean? Well, what it means, by the way, there's vacuum energy in this room that you could measure. There are particle. And it doesn't mean there's nothing. It means particle antiparticle pairs that pop into existence.
Chuck Nice
Yes.
Katie Freese
They last infinitesimal amount of time and then they disappear again. But that serves as an energy. And it has been measured. There's been two plates that are trapped.
Neil deGrasse Tyson
It's not the Casimir effect.
Katie Freese
Yes, the Casimir effect. It's the Casimir effect. Absolutely.
Neil deGrasse Tyson
This is where two in a vacuum, two parallel plates, you bring them very, very close together and there's a point where there's.
Chuck Nice
They just attract, right?
Katie Freese
Yep.
Chuck Nice
They just attract.
Neil deGrasse Tyson
Yeah. Yeah.
Katie Freese
Yep, yep, yep, yep. It's the same vacuum. The same. Exactly the same thing.
Chuck Nice
That's pretty wild.
Katie Freese
But if you do the mathematical calculation, your answer is too big by 10 to the 120 in the exponent. So if you add up all the contributions from all those particles, it gets the wrong answer. And that's considered one of the biggest.
Neil deGrasse Tyson
It gets the very wrong answer.
Katie Freese
One of the deepest unsolved problems in all of physics.
Neil deGrasse Tyson
All right.
Katie Freese
Wow. But it gets worse. People thought, well, it gets worse. It gets worse. People thought, look, somehow somebody will figure out how to bring that number down to zero and we'll be good. No. All of a sudden it looks like there's a small amount left over. Well, it's not that small for our universe, but compared to 10 to the 120, there's dark energy, which means there is some vacuum left over. That's driving acceleration. It's neither the big answer nor is it zero. It's somewhere in between. What the heck?
Neil deGrasse Tyson
All right.
Katie Freese
I feel like I'm talking too much.
Neil deGrasse Tyson
No, we love it. That's the whole point of why you're on it.
Chuck Nice
Ooh, wow.
Neil deGrasse Tyson
If you're talking a lot, it means I have less to add. So it is. Your words and ideas and brilliance are gracing the scene.
Chuck Nice
You're a real expert
Katie Freese
on some things.
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Chuck Nice
All right, let's go to Sumik Sharma who says hello, Dr. Tice and Dr. Freeze Lord. Nice. This is Sumit from Delhi. I am a new member here.
Neil deGrasse Tyson
Nice. Okay, Patreon member.
Chuck Nice
Welcome, welcome. Well, go ahead. You do it.
Neil deGrasse Tyson
Welcome to the universe.
Chuck Nice
There you go. You got an official welcome.
Neil deGrasse Tyson
There's my cosmos voice. That.
Chuck Nice
That's right. I want to know where does the scientific consensus stand on WIMP as an alternative hypothesis to dark matter today? I don't understand that. But anyway, I don't understand.
Neil deGrasse Tyson
WIMP is the abbreviation.
Chuck Nice
We can interact in mass.
Katie Freese
It's a candidate for the dark matter.
Chuck Nice
Oh, okay. But it can't be a substitute.
Katie Freese
But anyway, no, it is. It is a type of dark matter.
Chuck Nice
It's a type, right. That's what. That's the answer. Also, since dark matter is invisible and hard to to detect directly, what indirect properties or effects of dark matter are scientists currently studying and by what methods? I love that. Like, yeah. So what's the deal? It doesn't interact with anything. How are you guys measuring it? How are you figuring out anything about it?
Katie Freese
You know, the thing about dark matter is We've got about 20 different candidate particles that it could be.
Neil deGrasse Tyson
Okay.
Katie Freese
Some of them are well motivated and some are not as much. So my favorite three would be WIMPs, axions, and primordial black holes. Okay, so WIMPs, the weakly interacting massive particles, they do have an interaction, which is the weak interaction, the weak force.
Chuck Nice
Okay.
Katie Freese
And axions, what they do is that they can actually, in the presence of a magnetic field, they turn into photons, into light. So they can switch axion photon, axion photon, and then you can detect that light. Now, primordial black holes, they would be black holes that formed very early in the history of the universe.
Neil deGrasse Tyson
They don't evaporate right away.
Katie Freese
Some of them do. So they have to be bigger than the smallest ones do. But there would be some leftover. And they form wherever there's some region of the universe that has more an excess of stuff in it and over density that collapses into a black hole. And that, for example, could be at some phase transition in the early universe. This is like when water boils, it switches from liquid to gas, and that's where you get these fluctuations and boom, you would make primordial black holes. And the reason people care nowadays is because gravitational wave detectors are seeing merging black holes. And some of those could be primordial black holes. So people got all excited about primordial black holes again. Okay, as far as wimps go, there's. Oh, you can either. To find them. You can make it shake it or break it.
Chuck Nice
Right on. Go ahead, do your thing. Shake what your mama gave you.
Katie Freese
Let's talk about the make it first.
Chuck Nice
Shake it or break it.
Katie Freese
Yeah, make it. Shake it or break it. So the make it is in particle accelerators, such as the Large Hadron Collider at cern, you shoot really rapidly moving protons into each other, moving nearly at the speed of light, and out come potentially dark matter particles like WIMPs. And you look for them that way. No discovery yet.
Neil deGrasse Tyson
Okay, so it would have a signature that you couldn't otherwise identify, and you would describe it to dark matter.
Katie Freese
Yeah.
Neil deGrasse Tyson
Because you otherwise know what you're supposed to get out of it, right?
Katie Freese
Yeah. If it's ordinary stuff, then you know what to expect. But if you're making some kind of new particles, then they might escape from the detector without. And you'd see that as missing energy.
Neil deGrasse Tyson
Okay.
Katie Freese
You'd add up all the energy of all the particles coming out.
Neil deGrasse Tyson
Right.
Chuck Nice
Right on. Okay, There you go.
Katie Freese
And do you want to hear about the shake it?
Chuck Nice
Yes, and break it. I mean, now we gotta make it. You can't leave without shaking it and breaking it.
Neil deGrasse Tyson
All right.
Katie Freese
Okay. So the shake it is. You've got your detector deep underground, and a particle comes along, hits your detector, gives it a little bit of energy, and you look for that energy deposit. So it's shaking that nucleus.
Chuck Nice
It's like a little vibration.
Katie Freese
Exactly. In some cases, that's exactly what they're looking for.
Chuck Nice
In some cases. Gotcha, Gotcha.
Katie Freese
Or some light that comes off or whatever. So that's what they're doing.
Chuck Nice
Okay.
Katie Freese
And then the break it. That's called indirect detection. And that's when. Well, dark matter particles, these wimps can be their own antimatter. And that means when they hit each other, they annihilate and turn into something else. And what you gotta do is measure that something else. So people are looking for neutrinos, you know, where they look, where those detectors are underneath the ice at the South Pole.
Neil deGrasse Tyson
That's Ice Cube.
Katie Freese
That's Ice Cube.
Neil deGrasse Tyson
Ice Cube.
Katie Freese
Yep. Two miles down.
Chuck Nice
Straight out of Compton. I mean, straight out of South Pole.
Katie Freese
Oh, that's good. That's good. That's good.
Sponsor/Ad Voice
Yeah.
Neil deGrasse Tyson
Because Ice Cube was in Straight Outta Compton. Yes, he was the actor.
Katie Freese
Yeah, yeah, yeah. That's good.
Neil deGrasse Tyson
The rapper.
Katie Freese
We like that. Yeah. All right.
Chuck Nice
Yeah. That was great. That was. What a great question. Sue me for your first time asking anything here on StarTalk. And what a.
Neil deGrasse Tyson
From Old Deli.
Chuck Nice
From Old Deli. Make it shake it or break it. Just remember that. All right, all right. This is Chris Hampton. He says dear Lord Nice or Baron.
Katie Freese
Wait a minute. Christopher Hampton, that was a playwright. Is a playwright.
Neil deGrasse Tyson
Really? Okay.
Chuck Nice
I'm not familiar with him.
Katie Freese
Yes.
Chuck Nice
Oh, very well.
Neil deGrasse Tyson
Is it a living playwright?
Katie Freese
I think so.
Neil deGrasse Tyson
Okay, so it could be him. Okay. Treat him nice.
Chuck Nice
There you go. He says, dear Lord Nice or Baron. No, actually, you dubbed Paul Mercurial Baron. So I. It's just which, by the way, I found out they're kind of the same, the titles, which, you know, we're gonna have to demote.
Neil deGrasse Tyson
Paul.
Chuck Nice
I'm joking. I love him. Could dark energy be caused by a constant inflow of space time itself, perhaps through black holes from a parent universe? In other words, we're bringing more in than there is flowing out like a Brita Flat Iron system. Okay.
Katie Freese
Oh, wow.
Neil deGrasse Tyson
Yeah.
Katie Freese
Not sure how to answer that one.
Neil deGrasse Tyson
Brita Flat Iron System.
Katie Freese
Yeah. What the heck is that?
Chuck Nice
I don't know what a Brita Flatiron system is. I have a brother at home. I put water in it and it flows through and then I Drink it.
Katie Freese
But I mean, you know what Einstein had to do to get a static universe? He had to have material somehow bubbling into our universe and appearing out of nowhere on a regular basis. So that is not an insane idea. People have thought about that.
Neil deGrasse Tyson
You know what Isaac Newton's solution to that was?
Chuck Nice
Go ahead.
Neil deGrasse Tyson
It was if the universe were just finite, then all the galaxies would collapse to each other. Okay, okay. He didn't think of the universe as expanding, but he said the only way out of this is if the universe is infinite.
Chuck Nice
Right.
Neil deGrasse Tyson
Then you can't favor one point or another.
Katie Freese
Oh, really? Newton said that?
Neil deGrasse Tyson
Yes.
Katie Freese
Wow.
Neil deGrasse Tyson
Yes.
Katie Freese
Smart guy. Damn.
Neil deGrasse Tyson
That's why he's sitting right over there on my desk.
Chuck Nice
Did he know the. That's because he didn't know the universe was expanding, right?
Katie Freese
No, no, no, no. That was 1929 that they figured out Einstein did not like it.
Neil deGrasse Tyson
Yeah. Expanded universe was too weird for everybody.
Chuck Nice
For everybody. What did Einstein say something about God or playing.
Neil deGrasse Tyson
He's always talking about God.
Katie Freese
That was quantum mechanics.
Chuck Nice
It was quantum God playing dice. But the expanding universe. Yeah.
Katie Freese
He didn't like the quantum mechanics. He didn't like the expanding universe. Isn't that interesting? Which a lot of this is. These are fields of physics that he started.
Neil deGrasse Tyson
He created.
Chuck Nice
Fell off his plate from the stuff that he was.
Neil deGrasse Tyson
The Nobel Prize is given to crumbs. It fell off off his plate.
Chuck Nice
Well, I don't know what the hell this is. Whatever. Let's move on. That's him. Wow. That's amazing.
Katie Freese
It is.
Chuck Nice
That's. That's pretty wild. All right. But when he says a constant inflow of space time itself.
Katie Freese
No, no, I don't. That doesn't make any sense to me, so I'm going to just say no.
Neil deGrasse Tyson
So. So spacetime can't come from another brain.
Chuck Nice
Right.
Katie Freese
Space time wouldn't. Would to me would include all of that stuff.
Chuck Nice
Gotcha.
Katie Freese
We are all living in. Within space.
Neil deGrasse Tyson
Okay.
Chuck Nice
Right.
Katie Freese
I'm a little uncomfortable with that notion.
Chuck Nice
Okay, listen, I'll accept that because we are all living in space time. So, you know, that's pretty simple to accept. Greetings, STEM nerds. Mike.
Neil deGrasse Tyson
Thanks for the compliment.
Chuck Nice
Yeah. There you go, buddy. Mike from Colorado here. Since the time of Edwin Hubble, we look at distant galaxies and calculate their speed based on the redshift we measure, which we attribute to the Doppler effect. However, we also know that photons lose energy when traveling out of the gravitational field, which also exhibits as a redshift. Given that dark matter accounts for some 80% of the gravitation in the universe. How do we know how much redshift is due to the doppler effect and how much is due to gravitation? Is it possible that the speeds we calculate for distant galaxies Are just an upper bound on their actual speeds?
Katie Freese
Well, there are. On the average, galaxies are moving apart from one another. That's the Hubble expansion. That causes light between some distant past and us now to stretch the wavelength of light stretches. However, there's no question when you go, for example, some of that light, if it goes through a galaxy on the way here or goes through a cluster of galaxies, that also changes its wavelength. And in fact, we use that to figure out where a cluster is or what a cluster's doing. So it's useful information, and we're very aware that you have both effects going on at the same time. So if you're inside our galaxy, like in this room, we're not feeling the expansion. We're not feeling it, but because I'm feeling it. Yeah, you're feeling it.
Neil deGrasse Tyson
So this reminds me of what they used to call the tired light model. The light's just too tight, Right. Come through.
Chuck Nice
I done been through a lot, y'.
Neil deGrasse Tyson
All.
Chuck Nice
I'm telling you. Traveling. Traveling between these galaxies. Y' all don't know.
Katie Freese
This is.
Chuck Nice
Lord, it's killing me, man.
Neil deGrasse Tyson
Killing tired light. Because it, you know, I don't even have mass.
Chuck Nice
I feel so damn heavy. Oh, y' all don't know. Y' all don't know. So, okay,
Neil deGrasse Tyson
so tau light would be reddened, right? Okay, it would be reddened. However, there's also spectral features of elements within the spectrum. So you could take regolite and it would redden. But if it's the expanding universe and it's doppler shifted, the lines would shift.
Katie Freese
Yeah.
Neil deGrasse Tyson
Yeah, they would shift. And it had nothing to do with red or anything. They would just shift and they shift.
Katie Freese
Yep, they sure do.
Neil deGrasse Tyson
They sure do.
Chuck Nice
Gotcha.
Neil deGrasse Tyson
And so you can still have tired light, but you can't blame that redness on the expanding universe.
Chuck Nice
Very cool. That's a good answer.
Neil deGrasse Tyson
And if we animate StarTalk, you will be the voice of the photon.
Chuck Nice
I done had a hug.
Katie Freese
Wait, now who's gonna be the wimp? Oh, and then, of course, before that, there were the machos.
Neil deGrasse Tyson
The machos.
Chuck Nice
Oh, that's right.
Neil deGrasse Tyson
Massive compact halo object.
Chuck Nice
Compact halo objects. Right.
Neil deGrasse Tyson
So for a while, we had machos, macho, and wimp.
Katie Freese
Yeah.
Neil deGrasse Tyson
We did just show you that men were naming things.
Chuck Nice
Yeah, right.
Katie Freese
Yeah. And the Experiments. Looking for machos.
Sponsor/Ad Voice
Ogle.
Neil deGrasse Tyson
Ogle. Yeah.
Katie Freese
Eros. Ogle. Eros and macho.
Neil deGrasse Tyson
Yeah.
Chuck Nice
Okay.
Neil deGrasse Tyson
Ogle. Optical gravitational lens experiment.
Chuck Nice
Okay.
Neil deGrasse Tyson
And.
Katie Freese
Eros.
Neil deGrasse Tyson
E R O S. What did that stand for?
Katie Freese
I don't know. The God. The God of love. Like Cupid?
Neil deGrasse Tyson
Yeah, yeah, yeah, yeah.
Chuck Nice
It's the only one I like.
Katie Freese
What's wrong with Venus?
Chuck Nice
Well, first you ogle, and that causes arrows.
Neil deGrasse Tyson
We got time for one last question, if you can answer it fast. Okay, Go.
Chuck Nice
Okay, here we go. This is Brian Wheeling.
Neil deGrasse Tyson
It's a test of you.
Chuck Nice
Brian Whelan says hello. Dr. Tyson. Freeze. And Lord Nice. Captain Ben from Sag harbor here, reaching out 30,000 35, 000ft en route home. Oh, he's. He's actually in the cockpit sending us this. This message.
Neil deGrasse Tyson
Because he's captain.
Chuck Nice
He's captain.
Neil deGrasse Tyson
Should you be flying the plane?
Chuck Nice
Well, no. 35, 000ft. The plane flies itself.
Neil deGrasse Tyson
Okay.
Chuck Nice
He goes. Still? Yeah. Still. Yeah. This doesn't inspire confidence.
Sponsor/Ad Voice
Okay.
Chuck Nice
That's all we're saying.
Sponsor/Ad Voice
Okay.
Neil deGrasse Tyson
Okay.
Chuck Nice
I'd rather you be drinking.
Sponsor/Ad Voice
Stop.
Chuck Nice
All right, drink it.
Neil deGrasse Tyson
But still paying attention.
Chuck Nice
Exactly. He says, listen, I've been wondering. Does dark matter coalesce and condense similarly to regular matter? And if not, why not? It doesn't interact electromagnetically, but would gravity do something similar? Sending this message, also on my birthday. Happy birthday, Captain Whelan.
Neil deGrasse Tyson
Captain Whelan.
Katie Freese
There you go.
Neil deGrasse Tyson
So that has some overlap with the previous question, but let me tune that a little better. All right. If it interacts weakly, that's still an interaction. So why doesn't it just make weak planets instead of regular planets?
Katie Freese
Well, I'm gonna answer. I'm gonna say something else first, which is that without dark matter, we wouldn't exist. It had to collapse and clump and make proto galaxies before ordinary matter could do it. And then ordinary matter falls into the.
Neil deGrasse Tyson
So you're telling me that there are proto galactic dark matter galaxies out there?
Katie Freese
There were in the early universe, and then ordinary matter fell in there. But is it possible there are some purely dark galaxies that don't have any stars in them? Yes. And people are looking for that, for sure.
Neil deGrasse Tyson
Wow.
Katie Freese
Isn't that cool?
Neil deGrasse Tyson
Wait, wait, wait. Okay, yes, very cool. Very cool. So it wouldn't so much be dark. Cause that would imply it absorbed light. But they don't interact with light. They would just be invisible.
Katie Freese
Well, made of dark matter. Right. So there's nothing to see.
Neil deGrasse Tyson
There's nothing to see.
Katie Freese
Well, except.
Neil deGrasse Tyson
No, no, no. If it doesn't interact with light. Then light just passes through, rendering them transparent.
Katie Freese
No, because of Einstein's lensing. Gravitational lensing.
Neil deGrasse Tyson
Oh. You see the lensing effects.
Katie Freese
You see distant galaxies. The light from behind the dark galaxies will get bent.
Neil deGrasse Tyson
Okay, so it gets big.
Katie Freese
I could see that.
Neil deGrasse Tyson
But the galaxy itself or the dark matter thing itself would be invisible to you. You could just walk through it and you wouldn't even know.
Katie Freese
Yes.
Chuck Nice
Ooh, that's cool.
Neil deGrasse Tyson
There's some serious science fiction material there.
Chuck Nice
There is?
Katie Freese
Yes.
Chuck Nice
Interesting. I love it.
Neil deGrasse Tyson
Chuck, have you met my dark matter friend?
Chuck Nice
Oh, wow. He looks like a black rabbit.
Neil deGrasse Tyson
What's a black rabbit?
Katie Freese
Harvey the Rabbit.
Chuck Nice
There you go. Harvey was a white rabbit. He's dark matter. He's a black rabbit.
Neil deGrasse Tyson
Oh, sorry.
Chuck Nice
Okay, I just went too far too fast. I went too far too fast. This is what happens.
Neil deGrasse Tyson
Well, Katie, thanks for joining us again.
Katie Freese
Thank you.
Neil deGrasse Tyson
That was fun.
Chuck Nice
Another great show.
Neil deGrasse Tyson
Now, if I remember correctly, you have kin in the city.
Katie Freese
So you my boy, my son.
Neil deGrasse Tyson
Your son. So you get through town every now and then.
Katie Freese
I do all the time.
Neil deGrasse Tyson
We will nab you 100% of the time.
Katie Freese
I have a rent stabilized apartment. I just signed a two year lease, so I'll be here.
Neil deGrasse Tyson
Whoa. All right. Whoa. Yeah, okay. We will. Every time you come back here, you're coming right in. You're going to sit right there and
Katie Freese
actually, those queries were fun.
Neil deGrasse Tyson
See, even though you hadn't heard, we're seeing them before.
Katie Freese
That's right.
Neil deGrasse Tyson
Yeah.
Katie Freese
Okay, we're good.
Neil deGrasse Tyson
All right, good.
Chuck Nice
Well, the audience knows you now, so believe me, they got a lot more questions for you.
Katie Freese
Sounds great. And you guys are so much fun.
Neil deGrasse Tyson
Oh, well, thank you. Yeah. Well, there, give me a fist bump on that. All right.
Sponsor/Ad Voice
All right.
Neil deGrasse Tyson
This has been another StarTalk, Cosmic Queries, a Cosmology edition. I'm loving these.
Chuck Nice
Nice.
Neil deGrasse Tyson
And how many cosmologists we got? We got Jana, we got Brian.
Katie Freese
Our Jan.11, just so you know, was my first graduate student.
Sponsor/Ad Voice
Whoa.
Chuck Nice
Yeah, Very cool. Look at that.
Neil deGrasse Tyson
Okay, and we have the two Brians.
Chuck Nice
Yep.
Neil deGrasse Tyson
We have Brian Cox and Brian Greene. That's. What more do you need? Yeah, we got.
Chuck Nice
We got Chuck Lew, too.
Neil deGrasse Tyson
Oh, Charles Lew. But he's not deep cosmology. He's extra galactic guy.
Chuck Nice
Extra galactic guy.
Neil deGrasse Tyson
Yeah, yeah, yeah, yeah. All right.
Chuck Nice
We got enough?
Neil deGrasse Tyson
Yes, enough. Definitely.
Chuck Nice
Anybody else out there? Come on.
Neil deGrasse Tyson
All right, we got a call of quits there, Chuck. Always good to have you.
Chuck Nice
Always a pleasure.
Neil deGrasse Tyson
Katie. You're going to be a regular from now on.
Katie Freese
That sounds great.
Neil deGrasse Tyson
All right.
Sponsor/Ad Voice
Love it.
Neil deGrasse Tyson
You got it. Neil DeGrasse Tyson, your personal astrophysicist, as always bidding you to keep looking up.
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Host: Neil deGrasse Tyson
Guest: Dr. Katherine Freese (Director, Weinberg Institute for Theoretical Physics, UT Austin)
Co-host: Chuck Nice
Date: March 17, 2026
In this lively Cosmic Queries edition of StarTalk, Neil deGrasse Tyson and comedian Chuck Nice welcome renowned cosmologist Dr. Katherine Freese back to the show. The episode dives deep into the mysteries of dark matter and dark energy, new approaches to their detection, the legacy of foundational physicists, and the latest cosmological questions from curious listeners. Blending science, wit, and pop culture, the trio explores the unseen fabric of the universe—and has a few laughs along the way.
A. Dark Stars (27:16–30:03):
B. Dark Energy’s Weirdness (33:07–36:31):
C. WIMPs and Other Candidates (39:28–42:50):
D. Do Dark Matter and Dark Energy Form Structures? (51:47–53:39):
| Segment | Start Time | |-------------------------------------|:--------------:| | Dr. Freese’s background & "The Cosmic Cocktail" | 03:04 | | Introduction to dark matter detection methods (xenon/paleo) | 07:53 | | Paleo detector concept | 11:42 | | James Webb discoveries & early galaxies | 07:09 | | Is dark energy changing? (DESI experiment debate) | 19:11 | | Occam’s Razor discussion | 22:00 | | Cardassian cosmology & extra dimensions | 23:58 | | Dark stars explained (Q&A) | 27:16 | | "Make it, shake it, break it" dark matter detection | 41:48 | | Dark galaxies and lensing effects (Q&A) | 52:07 | | Notable quotes & science humor | Throughout |
The episode is conversational, humor-infused, yet deeply informative. Neil, Chuck, and Katherine balance pop culture (from Star Trek to the Cardassians to Hoop Dreams) and the seriousness of cosmic mysteries—to the delight of new and veteran StarTalk fans alike.
Closing gesture:
Tyson: "Katie, you're going to be a regular from now on."
Freese: "That sounds great." (55:37)
For listeners intrigued by the frontier of cosmology, dark matter, and dark energy, this episode provides clarity, curiosity, and comedic relief—plus, you just might walk away saying, 'Make it, shake it, or break it!'