Dark Universe Decoded with Katherine Freese

Summary

StarTalk Radio: "Dark Universe Decoded with Katherine Freese"

Host: Neil deGrasse Tyson
Guest: Dr. Katherine Freese (Director, Weinberg Institute for Theoretical Physics, UT Austin)
Co-host: Chuck Nice
Date: March 17, 2026

---

Episode Overview

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.

---

Key Discussion Points & Insights

1. Dr. Freese's Background & The Weinberg Institute

• Katherine Freese reflects on her career and her admiration for Steven Weinberg, a founder of the Standard Model. She recounts being recruited to UT Austin by him, calling him "the greatest physicist of our time" (04:27), and describes launching the Weinberg Institute in his honor.
• Book Plug: "The Cosmic Cocktail" (06:11), Freese’s "three parts dark matter, seven parts memoir" popular science book, remains influential a decade after publication.

2. Dark Matter Detection: Xenon and Paleo Detectors

• Traditional Approach: Most dark matter experiments use giant vats of liquid xenon deep underground to catch rare interactions with dark matter particles (08:09).
  • Why xenon? "We know how to build a detector with xenon. ...the dark matter comes along, hits one of these xenon atoms, deflects off of it, and the xenon gets some energy deposited in it..." —Katie Freese (08:12)
  • Detectors are placed deep underground to avoid interference from cosmic rays, which bombard the surface, making detection of rare dark matter events more feasible (10:29).
• New Approach: Paleo Detectors (07:53, 11:42)
  • Instead of building massive detectors, paleo detectors study tiny minerals from deep underground, which have been collecting dark matter and neutrino tracks for up to a billion years.
  • Key mineral: Olivine—suggested by geologists as ideal for this work. Meteorites called pallasites contain striking olivine crystals (12:37–13:39).
  • Advantage: "We're replacing volume with time. Isn't that cool? Hence paleo." —Katie Freese (11:42)
  • Paleo detectors might also provide information about historic supernovae via neutrino tracks stored in ancient rocks.

3. James Webb Space Telescope & Early Galaxies

• Neil introduces the paradox of detecting early galaxies that shouldn’t exist yet according to standard models (07:09).
• Dr. Freese discusses the impact of new instruments like the James Webb Space Telescope on cosmology and the search for "dark stars" (28:22–29:46).

4. Dark Energy Debate: Is It Changing?

• Tension exists over whether direct measurements suggest dark energy is decreasing, as some experimental data hint (DESI experiment vs. Dr. Freese's own analyses).
  • Freese: "We do not find that evidence to be very strong... There's a big debate. Is the dark energy changing with time or not?" (20:21)
  • Occam's Razor: Neil lauds Freese’s simpler interpretation—"Multiplicity ought not be posited without necessity"—and bets on her simpler model (22:00).

5. Modified Gravity, Extra Dimensions, and Cardassian Cosmology

• The group explores the theoretical idea of modifying Einstein’s equations and higher-dimensional "brane" universes:
  • Freese: "In string theory... our universe is a three-dimensional surface ... there could be another one and the stuff in between—the 'bulk'—is pulling on our surface..." (24:12)
  • Cardassian Cosmology: Dr. Freese named a variant model (inspired by Star Trek's Cardassians), in which accelerated expansion arises from new dynamics, not exotic dark energy (26:08).
  • "The equations would be different. And so, like the Cardassians, they are ... weird looking, but they're two bipeds like we are, and their goal is accelerated expansion of their evil empire." —Katherine Freese (26:42)

6. Listener Q&A Highlights

A. Dark Stars (27:16–30:03):

• Not made of dark matter but powered by dark matter within them.
• "They start out at about the same mass as the sun, but... become a million times as massive and a billion times as bright." —Freese (28:47)
• Candidates for dark stars have been observed by the James Webb telescope.

B. Dark Energy’s Weirdness (33:07–36:31):

• Why doesn’t it clump like gravity? "For dark energy, it is completely different from matter. It is something that's causing a repulsive behavior. It's pushing things apart..." —Freese (33:45)
• The vacuum energy calculation is famously off by 10^120: "One of the deepest unsolved problems in all of physics." —Freese (35:56)

C. WIMPs and Other Candidates (39:28–42:50):

• WIMPs, axions, primordial black holes: All remain strong dark matter candidates.
• The fun summary of detection methods: "Make it, shake it, or break it." —Freese (41:48)
  • Make it: Try to produce dark matter in particle accelerators (41:58).
  • Shake it: Detect vibrations from dark matter particles hitting underground detectors (43:01).
  • Break it: Search for their annihilation products (IceCube neutrino observatory).

D. Do Dark Matter and Dark Energy Form Structures? (51:47–53:39):

• Dark matter can collapse and form structure—proto-galactic halos—in the early universe. "Without dark matter, we wouldn't exist. It had to collapse and clump and make proto-galaxies before ordinary matter could do it." —Freese (52:20)
• There might even be "dark galaxies" made purely of dark matter, detectable via gravitational lensing (53:16).

---

Notable Quotes & Memorable Moments

On Xenon Detectors

• "There would be billions [of dark matter particles] going through your body every second. ...Only one a month hits you." —Freese (08:26)
• "Xenon has become very expensive because the xenon experiments have bought the entire world supply." —Freese (11:31)

On Paleo Detectors

• "Replacing volume with time. Isn't that cool? Hence paleo." —Freese (11:42)

On The Scientific Process

• "Usually when you have a great idea, you kill it in 10 minutes because it violates some observation. Occasionally ... it survives those first 10 minutes... that's what's going on here." —Freese (30:11)

On Dark Energy

• "It is a complete mystery to all of us... We could call it gobbledygook." —Freese (23:11)
• "The calculation's too big by 10^120 in the exponent... That’s considered one of the biggest—one of the deepest unsolved problems in all of physics." —Freese (34:46–35:56)

On Occam’s Razor

• "Multiplicity ought not be posited without necessity." —Tyson (22:00)

On Cardassian Cosmology

• "Like the Cardassians, they're weird looking, but they're made of the same... their whole purpose is to take over everything." —Freese and Nice (26:42–26:54)

"Make it, Shake it, or Break it"

• A catchy summary of three detection methods for dark matter (41:48–43:48)

---

Timestamps for Important Segments

| 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 |

---

Final Thoughts and Episode Tone

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!'

Transcript

[Sponsor/Ad Voice]

This podcast is brought to you by Hotels.com make your next trip work for you. Hotel.com's new Save youe Way feature lets you choose between Instant Savings now or Banking rewards for later. It's a flexible rewards program that puts you in control with no confusing math or blackout dates. Book now at hotels.com Save youe Way is available to loyalty members in the US and UK on hotels with member prices online. Other terms apply. See cite for details.

[Chuck Nice]

Hey, are you traveling soon? Imagine arriving and actually understanding the language. Imagine being able to communicate with the people that are there waiting for you to arrive. Rosetta Stone's immersive, intuitive method helps you naturally absorb your new language. The lessons are simple. They fit into your day wherever you want them to. You learn at your own pace and you can access the lessons on laptop or your phone or your tablet. It's super easy, very convenient and important because of course, everybody loves it when you're able to communicate with them in their own language. Are you ready to start learning a new language this spring? Visit Rosetta stone.com startalktoday to explore Rosetta Stone and choose the language that's right for you. Now for me that language was Spanish one because you know, I live in this hemisphere and there's a lot of Spanish speaking people cause I secretly am listening to my mother in law talk about me behind my back and she doesn't even know that I understand what she's saying. All right, I've shared too much. How about you? Go to Rosetta Stone.com startalk today to explore Rosetta Stone and choose your language. Go to rosettastone.com startalk right now and begin your language learning journey.

[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]

Okay.

[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.

[Sponsor/Ad Voice]

Startalk Radio is supported by Claude from Anthropic. Science isn't about rushing to conclusions. It's about sitting with the uncertainty until it starts to make sense. CLAUDE is the AI built for that kind of thinking and anthropic committed to not running ads in Claude. So when you're chasing down an idea, there's nothing pulling you towards someone else's agenda. Try CLAUDE for free at Claude AistaTalk and see why problem solvers choose Claude as their thinking partner.

Eczema is unpredictable, but you can flare less with ebglis, a once monthly treatment for moderate to severe eczema. After an initial four month or longer dosing phase, about 4 in 10 people taking EBGLIS achieved itch relief and clear or almost clear skin at 16 weeks. And most of those people maintain skin that's still more clear at one year with monthly dosing.

EBGLIS Lebricizumab LBKZ, a 250 milligram per 2 milliliter injection is a prescription medicine used to treat adults and children 12 years of age and older who weigh at least 88 pounds or 40 kilograms with moderate to severe eczema, also called atopic dermatitis, that is not well controlled with prescription therapies used on the skin or topicals or who cannot use topical therapies. EBGLIS can be used with or without topical corticosteroids. Don't use if you are allergic to ebglis. Allergic reactions can occur that can be severe eye problems can occur. Tell your doctor if you have new or worsening eye problems. You should not receive a live vaccine when treated with EBGLIS before starting Ebglis, tell your doctor if you have a parasitic infection.

Ask your doctor about eglis and visit ebgliss.lilly.com or call 1-800-LilyRx are 1-800-545-5979. Step up your sweat with the Peloton Cross Training Tread Plus. Swivel your screen 360 degrees and follow your favorite instructors on and off your tread. Track your form and reps with the movement tracking camera. Feel supported as you train on the cushioned slat belt and move to the beat with sound by Sonos. Elevate your workouts with the cross training tread plus.

[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.

[Sponsor/Ad Voice]

Startalk Radio is supported by Claude from Anthropic. Science isn't about rushing to conclusions. It's about sitting with the uncertainty until it starts to make sense. Claude is the AI built for that kind of thinking and anthropic committed to not running ads in Claude. So when you're chasing down an idea, there's nothing pulling you towards someone else's agenda. Try CLAUDE for free at Claude AI StarTalk and see why problem solvers choose Claude as their thinking partner.

Eczema is unpredictable, but you can flare less with ebglis, a once monthly treatment for moderate to severe eczema. After an initial four month or longer dosing phase, about four in ten people taking mglis achieved itch relief in clear or almost clear skin at 16 weeks. And most of those people maintain skin that's still more clear at one year.

With monthly dosing MGLIS Lebricizumab, LBKZ a 250mg 2ml injection is a prescription medicine used to treat adults and children 12 years of age and older who weigh at least 88 pounds or 40 kilograms with moderate to severe eczema, also called atopic dermatitis that is not well controlled with prescription therapies used on the the skin or topicals or who cannot use topical therapies. EBGLIS can be used with or without topical corticosteroids. Don't use if you're allergic to ebglis. Allergic reactions can occur that can be severe. Eye problems can occur. Tell your doctor if you have new or worsening eye problems. You should not receive a live vaccine when treated with ebglis. Before starting Eglis, tell your doctor if you have a parasitic infection.

Ask your doctor about ebgliss and visit eglis.lily.com or call 1-800-lilyrx or 1-800-545-5979.

Walmart Express delivery can get what you need delivered in as fast as an hour. Whether it's baby formula, when you're down to the last scoop, pet food before the bowl runs empty batteries for a dead remote or a last minute gift, it is handled. Try Walmart Express Delivery today and get free delivery with promo code Express promotion valid for First Express delivery. $50 minimum subject to availability restrictions apply.

[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.

[Sponsor/Ad Voice]

Eczema is unpredictable, but you can flare less with epglis, a once monthly treatment for moderate to severe eczema after an initial four month or longer dosing phase. About 4 in 10 people taking EBGLIS achieved itch relief and clear or almost clear skin at 16 weeks, and most of those people maintain skin that's still more clear at one year with monthly dosing.

Emglus Lebricizumab LBKZ a 250mg per 2ml injection, is a prescription medicine used to treat adults and children 12 years of age and older who weigh at least 88 pounds or 40 kilograms with moderate to severe eczema, also called atopic dermatitis that is not well controlled with prescription therapies used on the skin or topicals or who cannot use topical therapies. EBGLIS can be used with or without topical corticosteroids. Don't use if you're allergic to ebglis. Allergic reactions can occur that can be severe. Eye problems can occur occur. Tell your doctor if you have new or worsening eye problems. You should not receive a live vaccine when treated with ebglis. Before starting ebglis, tell your doctor if you have a parasitic infection.

Ask your doctor about ebglis and visit eglis.lily.com or call 1-800-lilyrx or 1-800-545-5979.

Walmart Express delivery can get what you need delivered in as fast as an hour, whether it's baby formula, when you're down to the last scoop, pet food before the bowl runs empty, batteries for a dead remote or a last minute gift. It is handled. Try Walmart Express Delivery today and get free delivery with promo code. Express Promotion valid for First Express delivery order $50 minimum, subject to availability restrictions apply.