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Speaker 1: There are so many amazing, colossal mysteries out there, so

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Speaker 1: many parts of the universe that are hidden from us

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Speaker 1: that still need to be explained. I mean, you've got

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Speaker 1: dark matter, you got anti matter, you've got dark energy,

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Speaker 1: you got exotic matter, you got why anybody ever lives

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Speaker 1: in Virginia. So many things to figure out. And I've

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Speaker 1: noticed that lots of people out there, especially those folks

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Speaker 1: of you who write into me, are drawn to the

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Speaker 1: idea that some of these mysteries could be connected, that

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Speaker 1: maybe you could like solve two of them at the

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Speaker 1: same time. And I totally get why that's appealing, But

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Speaker 1: usually it doesn't work. Could anti matter be the dark matter? No?

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Speaker 1: Could dark matter explain dark energy? No? Is dark matter

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Speaker 1: the reason people live in Virginia? Probably? Also?

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Speaker 2: No?

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Speaker 1: But sometimes, very rarely there is a chance to connect

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Speaker 1: two things to help solve a mystery. And that's what

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Speaker 1: we're gonna do today on the show when we answer

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Speaker 1: the question could and I matter help us find dark matter?

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Speaker 1: Welcome to Daniel and Kelly's Extraordinary Universe.

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Speaker 3: Hello, I'm Kelly Wiener Smith, and I'm a biologist, and

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Speaker 3: I'm feeling superior today because at least we know what

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Speaker 3: parasites are made of.

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Speaker 1: Hi, I'm Daniel. I'm a particle physicist, and I'm hoping

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Speaker 1: that dark matter is somehow made of parasites. So I

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Speaker 1: can blame Kelly for not figuring it out sooner.

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Speaker 3: Oh, we've got to figured out.

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Speaker 1: Man.

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Speaker 3: If it ends up in our wheelhouse, dark matter will

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Speaker 3: be solved in no time.

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Speaker 1: What about biological dark matter? If you figured all that out?

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Speaker 3: Are you talking about poop?

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Speaker 1: And there we are, folks, record time from zero to

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Speaker 1: poop for biologists.

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Speaker 3: You know, I'm surprised I made it this long with

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Speaker 3: the biologist in the room. You do what you can.

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Speaker 1: But yes, there's an enormous amount about how our bodies

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Speaker 1: work and how it makes poop that we don't understand.

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Speaker 1: So there's dark matter in every field.

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Speaker 4: You know.

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Speaker 3: I would say we understand it, probably much better than

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Speaker 3: the dark matter in physics. But I guess your wife

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Speaker 3: does a lot of biology dark matter experiments, and do

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Speaker 3: you might say there's a lot we don't know.

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Speaker 1: Yes, and she has written grand proposals making that exact

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Speaker 1: pun as a veiled Pooh reference.

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Speaker 3: So I can only imagine how much fun it must

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Speaker 3: be to study feces. There's a lot of opportunities for jokes.

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Speaker 1: That's right. We try to avoid crappy humor, but you

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Speaker 1: know you can't escape it.

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Speaker 3: Oh, it's so great sometimes you need it. All right,

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Speaker 3: all right, we'll talk about physics dark matter today. How

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Speaker 3: long do you think before we have that figured out?

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Speaker 1: Wow? When are we going to figure out dark matter?

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Speaker 1: You know, it's incredible because it's been decades that we've

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Speaker 1: known this is a thing and not understood it. And

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Speaker 1: the discovery could be any moment. We have lots of

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Speaker 1: ways we're looking for it that could suddenly reveal something

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Speaker 1: about dark matter. We could find a dark photon that

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Speaker 1: communicates the whole new sector of particles. One of the

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Speaker 1: experiments could actually see a signal, So it could be

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Speaker 1: any moment. It's really impossible to predict. Or we could

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Speaker 1: keep looking fruitlessly for a century. The possibilities are really

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Speaker 1: almost endless. It's impossible to predict. I hope you figured

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Speaker 1: it out soon before I retire. Perspire and expire.

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Speaker 3: Don't exercise too hard, Daniel.

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Speaker 1: Perspiration prevents expiration, is my understanding.

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Speaker 3: No, that's true, that's true. It's good to perspire subtimes well, today,

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Speaker 3: we're gonna be talking about a path that might help

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Speaker 3: us understand dark matter. This is something I had never

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Speaker 3: thought about before today, which is you know often true

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Speaker 3: when you send me an outline for our discussions. And

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Speaker 3: so today you're gonna tell us if antimatter can help

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Speaker 3: us find dark matter exactly.

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Speaker 1: We are going to fall in the chop of trying

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Speaker 1: to connect two huge mysteries of the universe together, which

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Speaker 1: is something you see in pop science all the time,

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Speaker 1: and I get lots of emails from folks trying to

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Speaker 1: make connections between two different mysteries we presented on the show,

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Speaker 1: which I love. It means that they're thinking deeply about

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Speaker 1: the universe and they're trying to put the clues together.

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Speaker 1: And it's very tempting to imagine that you could like

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Speaker 1: solve two huge mysteries at once, but it doesn't always

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Speaker 1: work that way.

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Speaker 3: Are there physicists that are working on trying to solve

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Speaker 3: two mysteries at once or it's just like everyone admits,

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Speaker 3: it's just not going to be that easy. You know,

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Speaker 3: when we were talking to Hamas van Reet, I think

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Speaker 3: he was saying that when you work on string theory,

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Speaker 3: it pops out other solutions. But I guess that's different

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Speaker 3: than thinking that two things are connected. It's when you

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Speaker 3: study one thing and it turns out it explains multiple things.

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Speaker 3: That's sort of the opposite direction.

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Speaker 1: No, that's exactly the right example. That's the feeling you

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Speaker 1: get when you think, oh, wow, maybe we've uncovered some

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Speaker 1: corner of the truth because we're working on problem one,

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Speaker 1: it automatically solves this other problem we weren't even trying

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Speaker 1: to solve. It tells you that you're making deep connections. So, yeah,

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Speaker 1: everybody wants that experience because we have this feeling like

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Speaker 1: there is a true explanation for the universe and if

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Speaker 1: you just dig deep enough, we'll uncover it and it'll

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Speaker 1: bring everything together into this glorious moment of insight. But

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Speaker 1: you know, getting there involves chiseling away patiently at the

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Speaker 1: rock face of truth and hoping something falls into your lap.

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Speaker 1: And so what we're going to talk about today is

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Speaker 1: like one strategy people are using, and I think it's

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Speaker 1: really cool because it highlights how physicists are doing everything

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Speaker 1: they can to look for dark matter. We're looking for

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Speaker 1: it up the wazoo, out the wazoo, to the left

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Speaker 1: of the wazoo, like really everything we can imagine we

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Speaker 1: are doing to look for dark matter.

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Speaker 3: You've got that wazoo cover.

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Speaker 1: Oh yeah, if it's in the wazoo, we'll find it.

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Speaker 3: I think it's possible you're looking at the wrong spot,

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Speaker 3: but I hope that you find it. So anti matter

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Speaker 3: and dark matter, these are two concepts that I think

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Speaker 3: most people don't understand at all. So let's see what

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Speaker 3: our audience thinks about anti matter helping us understand dark matter.

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Speaker 3: What did they have to say about what insights we

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Speaker 3: might be covering today and if you would like to

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Speaker 3: share your insights with us, email us at questions at

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Speaker 3: Daniel and Kelly dot org.

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Speaker 1: So I wrote to people and I asked them can

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Speaker 1: antimatter help us find dark matter? Here's what people had

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Speaker 1: to say. As far as I know, dark matter only

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Speaker 1: interacts with gravitational and with antimatter and matter. Both interacting

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Speaker 1: with gravitation will force the same. As far as we

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Speaker 1: can tell, dark matter we don't think interacts with matter,

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Speaker 1: so it should not interact with antimatter.

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Speaker 2: Since we don't really understand much about dark matter, the

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Speaker 2: only thing we could observe is gravity, so perhaps we

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Speaker 2: can't detect antimatter, but gravity would be the same for

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Speaker 2: matter versus antimatter. Maybe that could be an explanation is

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Speaker 2: why we can't see it.

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Speaker 4: Since antimatter tends to annihilate when it interacts with other matter,

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Speaker 4: then maybe any sort of photon urse might represent interacting

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Speaker 4: with dark matter if we don't think that there's any

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Speaker 4: major amounts of regular matter in that area.

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Speaker 3: So I was happy to see that most of the

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Speaker 3: answers pretty much matched what I thought, which was I

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Speaker 3: don't see how, but you are going to shine that

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Speaker 3: light for us.

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Speaker 1: I am going to make a connection between dark matter

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Speaker 1: and antimatter. And these are great answers, by the way,

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Speaker 1: and they're right. Matter and antimatter annihilate, but that is

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Speaker 1: not helpful for dark matter. Dark matter might only interact gravitationally,

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Speaker 1: so it'd be difficult to find dark matter doesn't interact

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Speaker 1: with antimatter any differently than it interacts with matter. So

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Speaker 1: these are great answers and right on the money.

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Speaker 3: Definitely great answers, and I should say it expressed a

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Speaker 3: lot more physics knowledge than I have. Most of those answers.

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Speaker 3: So let's start with what do we know about what

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Speaker 3: dark matter is. You just gave us some hints about

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Speaker 3: what it is and what it isn't, But let's pretend

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Speaker 3: you didn't say any of that. Start from the beginning

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Speaker 3: for the neophyts of us, the dark matter neophyts.

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Speaker 1: So dark matter is amazing because we simultaneously know an

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Speaker 1: annoys amount about it and yet we know very little

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Speaker 1: about it. It's sort of paradoxical, like we cannot see

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Speaker 1: dark matter. It's something that's in the universe. It's not

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Speaker 1: actually dark. It's invisible. So the name already is confusing.

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Speaker 1: Like when you see dark matter on TV shows, you know,

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Speaker 1: spaceship is flying through a cloud of dark matter. They

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Speaker 1: show it as dark like black, like it's obscuring your view.

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Speaker 1: But in reality, dark matter is there, but it's invisible.

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Speaker 1: It's transparent, and that's because light passes through It doesn't

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Speaker 1: interact with it the way light passes through glass, but

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Speaker 1: even less so, like glass will refract light, but dark

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Speaker 1: matter doesn't refract light, though it actually can bend it

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Speaker 1: and lends it a little bit. We'll talk about that

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Speaker 1: in a minute. But dark matter is more than just invisible.

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Speaker 1: It's also intangible, like if you were in a cloud

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Speaker 1: of dark matter you wouldn't even notice you like pass

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Speaker 1: right through it. Dark matter can like phase through walls

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Speaker 1: without interacting at all. So it's this mysterious but sort

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Speaker 1: of omnipresent substance that it's also overwhelmingly dominant form of

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Speaker 1: matter in the universe. Like eighty percent of the matter

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Speaker 1: in the universe is dark matter. It's not weird or rare.

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Speaker 1: In fact, we are the weird and rare kind of

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Speaker 1: matter in the universe.

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Speaker 3: Okay, so it's the dominant matter in the universe, but

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Speaker 3: we can't see it or measure it, So how do

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Speaker 3: we know that it exists at all?

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Speaker 1: Yeah, so very mysterious. We don't know what it's made

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Speaker 1: out of. We only learned about it recently, and yet

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Speaker 1: we know a lot about it because we have detected

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Speaker 1: its contributions to the gravity of our universe in many ways.

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Speaker 1: And this is something I really want to underscore carefully,

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Speaker 1: because a lot of people think dark matter is like

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Speaker 1: a fudge factor, just something we add to the equations

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Speaker 1: and don't understand just because things aren't working out. But

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Speaker 1: dark matter is much more like this suspect in a

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Speaker 1: mystery novel. Do we know a lot about but we

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Speaker 1: haven't yet fingered. We know somebody slipped the knife into

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Speaker 1: the corpse at some point. We see the footprints, we

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Speaker 1: see the broken window. We have fingerprints, you know, we

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Speaker 1: have DNA samples. We just haven't found the suspect yet.

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Speaker 1: And so dark matter is like that.

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Speaker 3: I'm not a big fan of dark matter after that description.

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Speaker 3: It doesn't seem like a nice thing. But it helps

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Speaker 3: by holding everything together. Is that right? So I shouldn't

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Speaker 3: be so negative.

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Speaker 1: Yeah, No, dark matter is much more helpful than a murderer.

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Speaker 3: That's good. That's good. I mean it's a low bar,

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Speaker 3: but that's good.

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Speaker 1: So let's talk about how we know that dark matter

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Speaker 1: is there and what we know about it, because it

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Speaker 1: paints a very comprehensive picture of dark matter. So classically

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Speaker 1: we know about dark matter originally because of how galaxies rotate.

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Speaker 1: Galaxies are a bunch of stars, but they're also spinning,

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Speaker 1: and when things spin, they tend to lose stuff. Like

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Speaker 1: if you put a bunch of ping pong balls on

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Speaker 1: a Merry go round and you spin it, you don't

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Speaker 1: keep all the ping pong balls. They fly out. Because

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Speaker 1: things tend to move in straight lines unless they're being

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Speaker 1: bent into a curve, Like the reason the Moon stays

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Speaker 1: in orbit around the Earth is because gravity is holding

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Speaker 1: it in. So you can do this calculation and ask, well,

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Speaker 1: is there enough gravity in the galaxy to hold all

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Speaker 1: those stars in as we spin around at this crazy

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Speaker 1: high speed. You add up all the mass from all

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Speaker 1: the stars and the answer is no, and not even

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Speaker 1: close by the way, galaxies are spending way too fast

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Speaker 1: to hold the stars in, and yet they're not throwing

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Speaker 1: stars out into interstellar space. Very often it does happen.

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Speaker 1: But to provide enough gravity to hold the galaxy together,

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Speaker 1: you have to take all the mass of all the

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Speaker 1: visible stuff and multiply it by four or five. So

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Speaker 1: there's a huge amount of unaccounted for gravity. Right. The

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Speaker 1: gravity is there, it's holding the stars together. We don't

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Speaker 1: know what's providing it. That's the original evidence we have

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Speaker 1: for dark matter, and that's the one that makes people

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Speaker 1: feel like, oh, it's just a fudge factor. You're just

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Speaker 1: adding in a number to describe what you're seeing. You

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Speaker 1: don't really understand it because that's just one piece of evidence.

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Speaker 1: But we have like many more pieces of evidence as well.

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Speaker 3: And also I feel like if it was just a

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Speaker 3: fudge factor. Then it wouldn't be like times four. Yeah,

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Speaker 3: it would be like you know.

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Speaker 1: Plus five exactly. It's not a little tweak, right, it's

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Speaker 1: a total revolution in our understanding of what the universe

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Speaker 1: is made out of.

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Speaker 3: Yeah. So, like you're saying, even if we discovered another

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Speaker 3: Jupiter in our solar system, that still wouldn't explain.

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Speaker 1: No, you've got to discover five more hidden stars in

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Speaker 1: our solar system to multiply the mass of our solar

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Speaker 1: system by five. Jupiter is nothing in our solar system.

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Speaker 3: Yeah, okay, got it, all right, So you've told us

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Speaker 3: about one piece of evidence. You're assuring us that there's more.

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Speaker 3: What have been our most promising routes of research to

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Speaker 3: try to discover what it is that have failed so far.

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Speaker 1: Well, we've looked for dark matter in several ways. Essentially,

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Speaker 1: we assume dark matter is some kind of particle and

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Speaker 1: we look to see if it interacts with our kind

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Speaker 1: of matter in any way. So, for example, we have

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Speaker 1: huge underground tanks of stuff like liquid xenon, and liquid

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Speaker 1: xenon is very quiet, it doesn't like to interact. This

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Speaker 1: stuff is underground, so no cosmic rays get to it. Basically,

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Speaker 1: you have a big tank of liquid xenon and cameras

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Speaker 1: in there. You say, do you ever see a flash

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Speaker 1: of light? I mean, you shouldn't see any flashes of light.

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Speaker 1: But if dark matter, which could penetrate through all of

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Speaker 1: the Earth and make it to your tank of xenon,

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Speaker 1: occasionally does bump into your xenon and give it a push,

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Speaker 1: you'll see a flash of light as that xenon relaxes.

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Speaker 1: So you have your cameras underground on liquid xenon and

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Speaker 1: look for flashes of light. It's a crazy experiment, but

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Speaker 1: nobody's ever seen anything beyond what you expect from like

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Speaker 1: background radiation from the rocks and all this sort of stuff.

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Speaker 1: So quiet experiments looking for dark matter bumps haven't seen anything.

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Speaker 1: We've tried to make dark matter in the laboratory at

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Speaker 1: the large had Drunk collider. We can smash particles together

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Speaker 1: and make new kinds of stuff. If dark matter has

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Speaker 1: any kind of interaction with protons at all beyond gravity, right,

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Speaker 1: this should require some non gravitational interaction. We should be

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Speaker 1: able to make it at the large a dron collider,

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Speaker 1: and then it would appear as invisible particles. We can

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Speaker 1: tell when we made invisible particles with the Large Hadron

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Speaker 1: Collider because there's like something on one side of the

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Speaker 1: detector and nothing on the other side, so there's an imbalance.

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Speaker 1: But we've never seen an unexplained imbalance of particles.

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Speaker 3: Did we expect that we would when we started the

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Speaker 3: large Head Droun Collider.

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Speaker 1: We hoped, so. I was actually one of the people

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Speaker 1: really working deeply on this topic. A lot of my

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Speaker 1: grattudents have like a written phddcs on searching for dark

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Speaker 1: matter with the Large Hyde Drunk Colider. I was really

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Speaker 1: hopeful because colliders are so powerful you don't have to

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Speaker 1: know what you're looking for, how to make it very

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Speaker 1: general search for like what the universe can do. But

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Speaker 1: we didn't see anything, and you know, hey, that's research, it's.

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Speaker 3: Exploration, not the right wazoo.

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Speaker 1: Yeah exactly. And there's one other avenue for looking for

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Speaker 1: dark matter, but let's save that related because that's our

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Speaker 1: antimatter connection, Okay. And I want to remind people about

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Speaker 1: how else we know that dark matter is really a thing,

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Speaker 1: and not just like, hey, let's multiply gravity by four

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Speaker 1: and we see its effects all over the place, not

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Speaker 1: just within galaxies, but between galaxies. Like dark matter is

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Speaker 1: not as clumpy as normal matter. It feels gravity, but

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Speaker 1: it's not sticky, so it doesn't stick together. Like two

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Speaker 1: blobs of dark matter, if they run into each other,

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Speaker 1: they just pass right through each other, whereas two blobs

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Speaker 1: of normal matter tend to stick together. So you get

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Speaker 1: like asteroids and planets forming out of matter, but you

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Speaker 1: don't get planetary structures forming out of dark matter. It's

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Speaker 1: like a big foamy fluff that fills the universe. It

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Speaker 1: has places where it's denser in places where it's less dense,

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Speaker 1: but it's much less clumpy than normal matter. So it

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Speaker 1: extends out between the galaxies, for example, and it helps

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Speaker 1: hold galaxy clusters together. Like we cannot explain using just

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Speaker 1: stars in their gravity why galaxies orbit each other the

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Speaker 1: way they do, and why galaxy clusters form. You need

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Speaker 1: dark matter to explain that too.

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Speaker 3: And you can tell that dark matter is clumpy based

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Speaker 3: on the activity of galaxies. Is that right?

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Speaker 1: Oh, great question. Yeah, we can tell where the dark

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Speaker 1: matter is based on the gravitational motion within a galaxy

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Speaker 1: and also between galaxies. Like we don't just take matter

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Speaker 1: and multiply by four. We can tell where in the galaxy.

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Speaker 1: That matter is based on the speed of the stars

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Speaker 1: at different distances from the center of the galaxy. Like

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Speaker 1: if you put all the dark matter at the very

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Speaker 1: center of the galaxy, then all the stars would be

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Speaker 1: feeling more gravity and it'd all be going really really fast.

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Speaker 1: If you take some of the dark man, you spread

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Speaker 1: it out, then it doesn't speed up the stars that

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Speaker 1: are closer into the galaxy. So by seeing how the

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Speaker 1: velocity of stars varies from the center to the edge

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Speaker 1: of the galaxy, you can tell where in the galaxy

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Speaker 1: it is, and the same thing applies for between the galaxies.

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Speaker 1: By seeing velocities of all these galaxies, you can make

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Speaker 1: a map of where the dark matter is between the galaxies.

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Speaker 1: And you can also see where the dark matter is

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Speaker 1: because of its lensing. I said earlier that dark matter

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Speaker 1: is kind of light glass, but it doesn't refract light,

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Speaker 1: but it does bend light because dark matter is matter,

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Speaker 1: and matter curves space, and curved space will curve the

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Speaker 1: path of photons. So if you have a huge blob

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Speaker 1: of dark matter between us and some other galaxy, it's

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Speaker 1: gonna lens that light, just like as if there was

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Speaker 1: some huge lens in space, and we see this in

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Speaker 1: the night sky, like we see sometimes two copies of

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Speaker 1: a single galaxy because it's light which shot out in

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Speaker 1: two different directions got then focused by some dark matter

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Speaker 1: lens back towards the Earth, so it looks like the

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Speaker 1: same galaxy, but it's not. It's a duplication. It's an

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Speaker 1: optical effect. And you can use this to map out

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Speaker 1: where the dark matter is in the universe by seeing

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Speaker 1: how the much lensing there is in various locations, So

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Speaker 1: we can tell where the dark matter is.

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Speaker 3: What kind of shape does it take? Does it say like,

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Speaker 3: oh got you physicists.

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Speaker 1: It's a big middle finger, that's right.

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Speaker 3: Yeah, it's just lumpy and kind of amorphis it's a.

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Speaker 1: Big cosmic poop. Basically, it's a big lump of no.

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Speaker 1: We can make a map and it's really fascinating, maybe

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Speaker 1: not surprising. The map of where the dark matter is

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Speaker 1: in the universe closely follows the map of where matter

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Speaker 1: is in the universe. It's kind of like luminous matter

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Speaker 1: stars are a tracer that tell you where the dark

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Speaker 1: matter is. And it's not a coincidence the luminous matter

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Speaker 1: the stars, the galaxies are there because the dark matter

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Speaker 1: is there. So origin of the universe, things are pretty

365
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Speaker 1: spread out, but there's little spots that are denser and

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Speaker 1: little spots that are less dense quantum fluctuations, and so

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Speaker 1: dark matter where it is denser, it started to gather together.

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Speaker 1: A little bit doesn't stick, but still it gathers together

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Speaker 1: a little bit and orbits itself and makes these big swirls,

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Speaker 1: and that makes it like a gravitational well. And the

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Speaker 1: other matter, gas and dust, normal matter falls into that

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Speaker 1: well and gets trapped and forms galaxies and forms stars.

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Speaker 1: And you can run simulations. If you run the universe

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Speaker 1: without any dark matter, you don't get galaxies ten billion

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Speaker 1: or twelve or fourteen billion years after the Big Bang,

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Speaker 1: You just don't. It takes much much longer. So the

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Speaker 1: only reason we have galaxies today is because dark matter

378
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Speaker 1: has gathered together the gas in the dust and forced

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Speaker 1: it to make stars and all this kind of stuff.

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Speaker 1: So we know that dark matter has played a huge

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Speaker 1: role in the evolution of what we call large scale

382
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Speaker 1: structure in the universe. Basically, the reason the universe looks

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Speaker 1: the way it is is because of.

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Speaker 3: Dark matter, and that interaction doesn't work both ways, right,

385
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Speaker 3: Like dark matter can pull objects towards it. But like

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Speaker 3: the Sun isn't pulling dark matter in because dark matter

387
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Speaker 3: doesn't respond to stuff.

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Speaker 1: The Sun is pulling dark matter in because dark matter

389
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Speaker 1: does feel gravity. But what happens when the Sun pulls

390
00:19:09,119 --> 00:19:11,359
Speaker 1: dark matter in? You're a blob of dark matter. You

391
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Speaker 1: get pulled towards the sun. Cool gravity is pulling you in.

392
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Speaker 1: You're going faster and faster and faster. Now, if you're

393
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Speaker 1: a comet, you hit the Sun, you vaporize, you interact electromagnetically, hadronically,

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Speaker 1: all the other kinds of interactions, like you become part

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Speaker 1: of the Sun. If you're a blob of dark matter,

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Speaker 1: you're a dark matter comet. What happens when you hit

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Speaker 1: the Sun? Nothing? You go right through it the same

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Speaker 1: way like if you dropped a ball through a hole

399
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Speaker 1: a tunnel that went all the way through the Earth,

400
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Speaker 1: what would happen. It would go all the way through

401
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Speaker 1: the center and come out the other side the same way.

402
00:19:41,680 --> 00:19:44,200
Speaker 1: Dark matter doesn't stick to the Sun. It passes right

403
00:19:44,200 --> 00:19:47,000
Speaker 1: through the Sun and goes out the other side. That's

404
00:19:47,000 --> 00:19:49,920
Speaker 1: why dark matter doesn't clump the way that normal matter does.

405
00:19:50,040 --> 00:19:52,840
Speaker 1: But it definitely does feel gravity. We have lots of

406
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Speaker 1: other reasons to believe that dark matter is there. Like,

407
00:19:54,880 --> 00:19:56,800
Speaker 1: we can tackle the problem from the other direction. Some

408
00:19:56,840 --> 00:19:59,560
Speaker 1: people are like, well, maybe you're just missing some of

409
00:19:59,600 --> 00:20:02,359
Speaker 1: the matter, Like are there just like big blobs of

410
00:20:02,400 --> 00:20:04,639
Speaker 1: matter out there you're not seeing, you know, could you

411
00:20:04,680 --> 00:20:07,359
Speaker 1: see a huge rock out in the middle between galaxies?

412
00:20:08,000 --> 00:20:09,960
Speaker 1: And so people have tackled the problem in this super

413
00:20:10,000 --> 00:20:13,399
Speaker 1: amazing way. From that direction, we're able to calculate how

414
00:20:13,480 --> 00:20:16,399
Speaker 1: much normal matter there is in the universe based on

415
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Speaker 1: what happened in the first few minutes of the Big Bang.

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Speaker 3: Wow.

417
00:20:20,840 --> 00:20:23,320
Speaker 1: Yeah, it's really incredible. We look at the distribution of

418
00:20:23,359 --> 00:20:25,800
Speaker 1: elements in the universe, how much hydrogen, how much helium,

419
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Speaker 1: how much lithium, et cetera, And those amounts are really

420
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Speaker 1: sensitive to the density of normal matter in the early universe.

421
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Speaker 1: Like the denser it was, the more you're going to

422
00:20:35,680 --> 00:20:39,080
Speaker 1: get fusion in the early universe to make those heavier elements,

423
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Speaker 1: and the less dense it was, the less likely you are.

424
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Speaker 1: So it's very sensitive, Like we can measure exactly what

425
00:20:44,880 --> 00:20:48,040
Speaker 1: the density of quarks and protons and all those kind

426
00:20:48,040 --> 00:20:50,680
Speaker 1: of normal matter bits were in the early universe by

427
00:20:50,720 --> 00:20:53,560
Speaker 1: measuring how much lithium is out there in space, and

428
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Speaker 1: so we can tell how much stuff there was very precisely,

429
00:20:57,119 --> 00:20:59,360
Speaker 1: and it very well matches the normal matter we see

430
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Speaker 1: in the universe. So that tells us like, yeah, there

431
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Speaker 1: could be a rock in the middle of space that

432
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Speaker 1: we didn't see, even like one the size of Jupiter

433
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Speaker 1: or a star, but there's definitely not a huge amount,

434
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Speaker 1: not four times the amount of normal matter missing. So

435
00:21:13,280 --> 00:21:15,120
Speaker 1: we sort of like accounted for this problem in two

436
00:21:15,160 --> 00:21:18,159
Speaker 1: different directions and it all adds up. And then the

437
00:21:18,240 --> 00:21:20,000
Speaker 1: sort of coup de grad the thing that like really

438
00:21:20,040 --> 00:21:22,480
Speaker 1: links it together is we can look at the very

439
00:21:22,600 --> 00:21:25,639
Speaker 1: very early universe. We see ripples from the plasma of

440
00:21:25,680 --> 00:21:28,320
Speaker 1: the very early universe. This it's called the cosmic microwave

441
00:21:28,359 --> 00:21:29,280
Speaker 1: background radiation.

442
00:21:29,760 --> 00:21:32,520
Speaker 3: Is this the thing that we thought was pigeon poop?

443
00:21:31,760 --> 00:21:35,600
Speaker 1: I'm that's really important exactly. Okay, This is discovered in

444
00:21:35,640 --> 00:21:38,240
Speaker 1: the sixties and it's evidence that the universe was once

445
00:21:38,440 --> 00:21:41,399
Speaker 1: much more dense. It was this hot, frothing plasma that

446
00:21:41,440 --> 00:21:43,960
Speaker 1: filled the whole universe, and it glowed, and there was

447
00:21:44,000 --> 00:21:47,480
Speaker 1: a moment when that plasma cooled and suddenly became transparent,

448
00:21:47,880 --> 00:21:51,000
Speaker 1: so that glow instead of getting constantly reabsorbed by itself,

449
00:21:51,000 --> 00:21:53,560
Speaker 1: the way like light inside the sun is getting absorbed

450
00:21:53,560 --> 00:21:55,960
Speaker 1: by the sun and we're only seeing light from the surface.

451
00:21:56,680 --> 00:21:59,159
Speaker 1: That plasma in the early universe became transparent, and so

452
00:21:59,200 --> 00:22:01,919
Speaker 1: that glow stuck and we can see that glow and

453
00:22:01,960 --> 00:22:05,440
Speaker 1: we can tell stuff about that plasma, and most importantly,

454
00:22:05,440 --> 00:22:07,639
Speaker 1: we see ripples in that plasma. It's not just like

455
00:22:07,720 --> 00:22:10,920
Speaker 1: a constant glow. It's like brighter here and darker there,

456
00:22:11,359 --> 00:22:15,680
Speaker 1: and those ripples depend on how that plasma is sloshing around,

457
00:22:16,119 --> 00:22:18,440
Speaker 1: and how the plasma slashes around depends on like, well,

458
00:22:18,600 --> 00:22:21,639
Speaker 1: how much dark matter is there holding stuff together with

459
00:22:21,680 --> 00:22:25,040
Speaker 1: its gravity, how many photons are there pushing things apart

460
00:22:25,200 --> 00:22:27,720
Speaker 1: because of the glow, how much normal matter is there

461
00:22:27,840 --> 00:22:30,320
Speaker 1: which feels the photons and the gravity. It's like this

462
00:22:30,440 --> 00:22:33,560
Speaker 1: complex dance of all the different ingredients of the universe

463
00:22:33,600 --> 00:22:36,480
Speaker 1: at that time, and those very specifically control all of

464
00:22:36,520 --> 00:22:39,680
Speaker 1: those wiggles. So by measuring those wiggles, we can nail

465
00:22:39,720 --> 00:22:42,360
Speaker 1: down exactly how much matter was there, how much dark

466
00:22:42,400 --> 00:22:44,800
Speaker 1: matter was there, how many photons were there, and it

467
00:22:44,840 --> 00:22:47,679
Speaker 1: all aligns up with our other calculations. So we have

468
00:22:47,800 --> 00:22:50,200
Speaker 1: like all these different pieces of evidence that tell us

469
00:22:50,640 --> 00:22:52,640
Speaker 1: how much of the universe is normal matter, how much

470
00:22:52,640 --> 00:22:57,879
Speaker 1: of the universe is this weird, unexplained gravitationally feeling otherwise

471
00:22:58,040 --> 00:23:02,400
Speaker 1: totally intangible kind of matter we call dark matter. So like, yeah,

472
00:23:02,400 --> 00:23:04,520
Speaker 1: we got a lot of clues, you just haven't yet

473
00:23:04,520 --> 00:23:05,440
Speaker 1: found the murderer.

474
00:23:05,560 --> 00:23:07,439
Speaker 3: So we've tried to see if it's a particle. No

475
00:23:07,520 --> 00:23:10,240
Speaker 3: evidence for that yet. We don't know if it could

476
00:23:10,280 --> 00:23:13,280
Speaker 3: do anything other than like gravitate and pull things in

477
00:23:13,320 --> 00:23:15,639
Speaker 3: towards it or respond to the gravity of other things.

478
00:23:15,680 --> 00:23:18,000
Speaker 3: But when we get back from the break, you're going

479
00:23:18,080 --> 00:23:20,560
Speaker 3: to bring us to the next big unknown, which is

480
00:23:20,600 --> 00:23:23,560
Speaker 3: anti matter, and we'll talk about what we don't know

481
00:23:23,640 --> 00:23:42,960
Speaker 3: about that, all right, So in the last segment, you

482
00:23:43,160 --> 00:23:45,920
Speaker 3: convinced me that dark matter is probably not just because

483
00:23:45,920 --> 00:23:48,480
Speaker 3: someone forgot to carry a five or something like that.

484
00:23:48,680 --> 00:23:50,960
Speaker 3: So now let's move on to anti matter, which is

485
00:23:50,960 --> 00:23:53,119
Speaker 3: the other thing that we need to understand to answer

486
00:23:53,119 --> 00:23:56,120
Speaker 3: the question what can antimatter tell us about dark matter?

487
00:23:56,440 --> 00:23:59,400
Speaker 1: Right, so forget everything we said about dark matter for now,

488
00:24:00,160 --> 00:24:03,520
Speaker 1: we're gonna talk about a completely separate topic in particle physics,

489
00:24:03,520 --> 00:24:06,640
Speaker 1: which is the mystery of anti matter. And then later

490
00:24:06,680 --> 00:24:09,880
Speaker 1: on we're going to connect these. But antimatter is amazing

491
00:24:09,960 --> 00:24:13,320
Speaker 1: and wonderful and real. It's like something we see, something

492
00:24:13,359 --> 00:24:17,280
Speaker 1: we make, something we study. It's like very pedestrian. In

493
00:24:17,320 --> 00:24:19,440
Speaker 1: the collider I used to work on before the Large

494
00:24:19,440 --> 00:24:23,119
Speaker 1: Hatener Collider, we collided matter and antimatter. We made protons

495
00:24:23,119 --> 00:24:26,879
Speaker 1: and we made anti protons. We smashed them together many

496
00:24:26,880 --> 00:24:30,320
Speaker 1: many times a second. So antimatter is not nearly as

497
00:24:30,400 --> 00:24:32,919
Speaker 1: mysterious as dark matter. We know what it is, we

498
00:24:32,960 --> 00:24:34,479
Speaker 1: know it's a particle. We can make it, we can

499
00:24:34,520 --> 00:24:37,120
Speaker 1: play with it, we build stuff out of it. It's

500
00:24:37,160 --> 00:24:40,240
Speaker 1: amazing in science fiction y, but it's much less theoretical

501
00:24:40,320 --> 00:24:41,160
Speaker 1: than dark matter.

502
00:24:41,400 --> 00:24:43,640
Speaker 3: Okay, you sounded a little bit defensive when we said

503
00:24:43,800 --> 00:24:46,320
Speaker 3: antimatter is real, but I guess you were just trying

504
00:24:46,320 --> 00:24:48,280
Speaker 3: to clarify that we've actually seen them.

505
00:24:48,600 --> 00:24:51,040
Speaker 1: Was I protesting too much? Well, I think some people

506
00:24:51,040 --> 00:24:53,560
Speaker 1: are confused because they read about it in science fiction.

507
00:24:53,680 --> 00:24:57,720
Speaker 1: It seems sort of like bizarre and mystical, but it's

508
00:24:57,800 --> 00:25:00,600
Speaker 1: actually something we play with all the time in real physics.

509
00:25:00,720 --> 00:25:02,679
Speaker 1: It's also just kind of a name we give things

510
00:25:03,040 --> 00:25:06,280
Speaker 1: that reveals something deep about the universe, which is that

511
00:25:06,320 --> 00:25:10,040
Speaker 1: the universe has these beautiful symmetries. Like basically, antimatter is

512
00:25:10,040 --> 00:25:12,800
Speaker 1: a statement that every particle out there has a partner.

513
00:25:13,359 --> 00:25:16,080
Speaker 1: So you have an electron, it's a particle, it has

514
00:25:16,160 --> 00:25:20,159
Speaker 1: negative charge. There's another version of that particle, the positively

515
00:25:20,280 --> 00:25:23,720
Speaker 1: charged version. You have a muon it's negatively charged. There's

516
00:25:23,720 --> 00:25:26,240
Speaker 1: a positively charged version of that. You have a quirk

517
00:25:26,280 --> 00:25:30,160
Speaker 1: with charge two thirds. There's a negative two thirds charged

518
00:25:30,240 --> 00:25:33,280
Speaker 1: version of that. Whatever the universe can do when it

519
00:25:33,320 --> 00:25:35,800
Speaker 1: makes a charged particle, it can also do something very

520
00:25:35,800 --> 00:25:39,200
Speaker 1: similar with the opposite charge. So it's actually this kind

521
00:25:39,200 --> 00:25:41,760
Speaker 1: of beautiful symmetry in the matter that we see out

522
00:25:41,760 --> 00:25:42,680
Speaker 1: there in the universe.

523
00:25:42,880 --> 00:25:44,600
Speaker 3: I'm kind of feeling like we should have saved this

524
00:25:44,680 --> 00:25:48,920
Speaker 3: topic for the Valentine's Day. It feels a little loveyw

525
00:25:49,040 --> 00:25:51,360
Speaker 3: but okay, all right, good to note the universe has symmetry.

526
00:25:51,440 --> 00:25:54,320
Speaker 1: Well, they have a very explosive relationship, because what happens

527
00:25:54,359 --> 00:25:56,680
Speaker 1: when an electron and positiron meet is they don't live

528
00:25:56,680 --> 00:26:00,000
Speaker 1: happily ever after they annihilate. And popular science tells you

529
00:25:59,840 --> 00:26:03,159
Speaker 1: that annihilating into pure energy. Really what happens is they

530
00:26:03,200 --> 00:26:05,840
Speaker 1: annihilate into a photon, which and a photon is nothing

531
00:26:05,880 --> 00:26:08,880
Speaker 1: but energy, that's true, but it's not this like abstract

532
00:26:08,960 --> 00:26:12,240
Speaker 1: form of energy. It's like it's another kind of field

533
00:26:12,240 --> 00:26:14,400
Speaker 1: that's rippling and making us a particle.

534
00:26:14,560 --> 00:26:16,720
Speaker 3: All right, Well, it's just some parasites get divorced too.

535
00:26:16,840 --> 00:26:19,560
Speaker 3: So I'm seeing connections here, and.

536
00:26:19,560 --> 00:26:22,040
Speaker 1: This is just an example of the kinds of symmetries

537
00:26:22,119 --> 00:26:25,040
Speaker 1: we see in the universe. We notice that it's not

538
00:26:25,119 --> 00:26:27,520
Speaker 1: just like forty two different particles and they're all different.

539
00:26:27,520 --> 00:26:30,120
Speaker 1: There are relationships between them, There are patterns between them,

540
00:26:30,359 --> 00:26:32,560
Speaker 1: and often the patterns work in just this way. There's

541
00:26:32,640 --> 00:26:35,600
Speaker 1: like several versions of the same particle. So there's an

542
00:26:35,600 --> 00:26:38,359
Speaker 1: electron and there's the positron, which is just like the

543
00:26:38,400 --> 00:26:41,080
Speaker 1: opposite version of the electron. Don't think of them as

544
00:26:41,119 --> 00:26:43,200
Speaker 1: separate particles. Think of them as two halves of the

545
00:26:43,280 --> 00:26:46,679
Speaker 1: same coin. But the electron is also one half of

546
00:26:46,760 --> 00:26:50,680
Speaker 1: other kinds of coins. For example, the electron has another version,

547
00:26:50,760 --> 00:26:53,040
Speaker 1: the muon. The muon is the same as the electron,

548
00:26:53,160 --> 00:26:55,960
Speaker 1: just heavier. The tao is just the same as the muon,

549
00:26:56,000 --> 00:26:57,640
Speaker 1: and the electron even heavier.

550
00:26:57,760 --> 00:27:00,320
Speaker 3: I feel like the coin analogy is breaking down. Yes,

551
00:27:00,440 --> 00:27:03,639
Speaker 3: we're talking about dungeons and dragons, dice or something.

552
00:27:03,520 --> 00:27:06,560
Speaker 1: And we think that the electron participates in even other symmetries.

553
00:27:06,640 --> 00:27:09,880
Speaker 1: This this whole theory called supersymmetry, which says that every

554
00:27:09,880 --> 00:27:13,240
Speaker 1: particle has this weird partner particle. So the electron would

555
00:27:13,240 --> 00:27:16,080
Speaker 1: have the selectron, and quirks would have the squarks, and

556
00:27:16,280 --> 00:27:18,200
Speaker 1: we haven't discovered those. We don't know if it's true,

557
00:27:18,400 --> 00:27:20,720
Speaker 1: but it's sort of a theme in particle physics that

558
00:27:20,800 --> 00:27:24,000
Speaker 1: every particle has reflections, other copies of itself.

559
00:27:24,080 --> 00:27:25,760
Speaker 3: This might be the first time where I've thought, oh,

560
00:27:25,760 --> 00:27:27,960
Speaker 3: physicists are doing a good job with naming something though,

561
00:27:27,960 --> 00:27:30,920
Speaker 3: because like the squirks, that's both cute and it sort

562
00:27:30,960 --> 00:27:32,280
Speaker 3: of tells you what it is, you know.

563
00:27:32,560 --> 00:27:35,760
Speaker 1: Yeah, yeah, I like the supersymmetric names. And it's also

564
00:27:35,920 --> 00:27:39,600
Speaker 1: kind of arbitrary, like what is matter and what is antimatter? Well,

565
00:27:39,640 --> 00:27:42,240
Speaker 1: the universe is very symmetric. The laws of physics are

566
00:27:42,280 --> 00:27:45,480
Speaker 1: almost the same for matter and antimatter, so they are

567
00:27:45,520 --> 00:27:48,160
Speaker 1: opposite each other in the sense they have opposite charges.

568
00:27:48,440 --> 00:27:51,200
Speaker 1: But it's not like antimatter is like against building stuff.

569
00:27:51,240 --> 00:27:53,439
Speaker 1: You could build a universe out of antimatter.

570
00:27:53,480 --> 00:27:55,600
Speaker 3: We think, but antimatter is the rare thing that we

571
00:27:55,640 --> 00:27:57,960
Speaker 3: don't see a lot of, right, and so what causes

572
00:27:58,000 --> 00:27:59,080
Speaker 3: that asymmetry? There?

573
00:27:59,200 --> 00:28:01,119
Speaker 1: Boy? Do I wish I had the answer to that question,

574
00:28:01,200 --> 00:28:04,040
Speaker 1: because I would be talking to the King of Sweden,

575
00:28:04,080 --> 00:28:06,960
Speaker 1: shaking their hand and getting a million dollars. Nobody knows.

576
00:28:07,040 --> 00:28:09,320
Speaker 3: Would you still podcast if you got the Nobel Prize?

577
00:28:09,320 --> 00:28:13,880
Speaker 1: Of course, absolutely, I podcast more often. Absolutely nice.

578
00:28:13,880 --> 00:28:15,040
Speaker 3: You'd remember the little people.

579
00:28:16,480 --> 00:28:18,639
Speaker 1: Oh, you're the little people right as you sit in

580
00:28:18,680 --> 00:28:20,600
Speaker 1: front of your shelf of awards over there.

581
00:28:22,760 --> 00:28:23,960
Speaker 3: The shelf is out of the screen.

582
00:28:24,119 --> 00:28:26,240
Speaker 1: Huh. If you won the Nobel Prize, your biggest problem

583
00:28:26,280 --> 00:28:27,960
Speaker 1: would be like where to put it on your shelf

584
00:28:28,000 --> 00:28:29,560
Speaker 1: otherwise crowded with prizes.

585
00:28:31,160 --> 00:28:33,680
Speaker 3: Oh you're making me feel really nice, but that's definitely

586
00:28:33,680 --> 00:28:35,359
Speaker 3: over selling. But thank you.

587
00:28:35,680 --> 00:28:38,240
Speaker 1: But you're right. It is a big mystery because if

588
00:28:38,240 --> 00:28:40,960
Speaker 1: it's true that the universe treats matter and anti matter

589
00:28:41,000 --> 00:28:43,720
Speaker 1: the same way, why are we made of matter? Why

590
00:28:43,760 --> 00:28:46,040
Speaker 1: is the Earth made of matter? The galaxy made of matter?

591
00:28:46,160 --> 00:28:48,160
Speaker 1: We think most of the galaxies near us are made

592
00:28:48,200 --> 00:28:50,960
Speaker 1: of matter. That's an asymmetry, and that doesn't seem to

593
00:28:51,000 --> 00:28:53,880
Speaker 1: add up because if the universe made the same amount

594
00:28:53,960 --> 00:28:56,720
Speaker 1: of matter and antimatter in the very beginning, when it

595
00:28:56,760 --> 00:28:59,240
Speaker 1: was filled with frothing energy which is then cooled into

596
00:28:59,240 --> 00:29:02,680
Speaker 1: these fields. Then that matter and antimatter would annihilate. And

597
00:29:02,800 --> 00:29:05,480
Speaker 1: that's mostly what happened when we made matter in antimatter

598
00:29:05,480 --> 00:29:07,720
Speaker 1: in the early universe. In annihilated and the universe was

599
00:29:07,760 --> 00:29:10,600
Speaker 1: mostly filled with photons for a little while, which must

600
00:29:10,600 --> 00:29:13,840
Speaker 1: have been brilliant. But there was a little bit left

601
00:29:13,840 --> 00:29:16,880
Speaker 1: over because there wasn't a perfect symmetry between the matter

602
00:29:16,920 --> 00:29:20,040
Speaker 1: and antimatter, and we don't know why. We don't know

603
00:29:20,440 --> 00:29:22,880
Speaker 1: was there more matter made in the early universe or

604
00:29:23,200 --> 00:29:26,000
Speaker 1: is there some process in the universe that produces matter

605
00:29:26,160 --> 00:29:30,160
Speaker 1: more than antimatter. There's definitely some asymmetry there because, as

606
00:29:30,200 --> 00:29:33,040
Speaker 1: you say, there's more matter and less antimatter. But I

607
00:29:33,080 --> 00:29:35,720
Speaker 1: also just want to emphasize like antimatter, we name it

608
00:29:35,760 --> 00:29:39,080
Speaker 1: antimatter because it's the one that's not made as often,

609
00:29:39,400 --> 00:29:41,719
Speaker 1: not because it's against anything.

610
00:29:42,520 --> 00:29:44,920
Speaker 3: You said that we don't know of universes that are

611
00:29:44,960 --> 00:29:48,000
Speaker 3: made of antimatter. Could there be universes of antimatter or

612
00:29:48,040 --> 00:29:50,840
Speaker 3: like a chunk of antimatter out in the galaxies or

613
00:29:50,880 --> 00:29:52,000
Speaker 3: whatever that we haven't seen yet.

614
00:29:52,040 --> 00:29:54,280
Speaker 1: Yeah, it's tempting to say, oh, let's look up at

615
00:29:54,320 --> 00:29:56,320
Speaker 1: the night sky. We see galaxies out there. How do

616
00:29:56,360 --> 00:29:58,680
Speaker 1: we know they're not made of antimatter because antimatter would

617
00:29:58,680 --> 00:30:01,720
Speaker 1: produce photons a way it matter does. And that's true.

618
00:30:01,800 --> 00:30:04,280
Speaker 1: But we can tell if some of those galaxies are

619
00:30:04,280 --> 00:30:08,280
Speaker 1: made of matter and antimatter, because galaxies don't just produce photons,

620
00:30:08,280 --> 00:30:12,240
Speaker 1: they also produce charged particles, like the Sun produces lots

621
00:30:12,280 --> 00:30:14,560
Speaker 1: of photons you can see it, but also lots of

622
00:30:14,600 --> 00:30:18,920
Speaker 1: protons and electrons, and so antimatter is much rarer. In

623
00:30:19,040 --> 00:30:22,920
Speaker 1: our solar wind we are shooting matter out into the universe.

624
00:30:23,440 --> 00:30:26,280
Speaker 1: And if a neighboring galaxy was shooting antimatter out into

625
00:30:26,320 --> 00:30:28,800
Speaker 1: the universe the same way as you would expect, then

626
00:30:28,880 --> 00:30:32,280
Speaker 1: between them there would be this like ribbon of collisions,

627
00:30:32,680 --> 00:30:36,120
Speaker 1: this like interface where our solar or galactic winds were

628
00:30:36,200 --> 00:30:38,960
Speaker 1: hitting their solar galactic winds and annihilating and making these

629
00:30:38,960 --> 00:30:39,720
Speaker 1: bright flashes.

630
00:30:39,840 --> 00:30:40,920
Speaker 3: I bet that would look awesome.

631
00:30:41,000 --> 00:30:43,440
Speaker 1: It would be amazing. I hope it's real when we've

632
00:30:43,480 --> 00:30:46,240
Speaker 1: looked for that and we haven't seen it, which means

633
00:30:46,480 --> 00:30:50,360
Speaker 1: either the whole universe is just matter, or if there

634
00:30:50,360 --> 00:30:52,640
Speaker 1: are anti matter galaxies, they're too far away for us

635
00:30:52,720 --> 00:30:55,360
Speaker 1: to see. Now, that doesn't rule out that, like we

636
00:30:55,400 --> 00:30:59,000
Speaker 1: live in a vast pocket of matter ninety billion light

637
00:30:59,040 --> 00:31:01,800
Speaker 1: years across and be on the edge of the observable universe,

638
00:31:01,920 --> 00:31:04,880
Speaker 1: there are vast pockets of antimatter. Maybe even most of

639
00:31:04,880 --> 00:31:07,920
Speaker 1: the universe is antimatter for all we know. But in

640
00:31:07,960 --> 00:31:11,080
Speaker 1: the region we can see, we can't spot any antimatter galaxies,

641
00:31:11,080 --> 00:31:14,160
Speaker 1: and we can't spot any interface between matter and antimatter.

642
00:31:14,240 --> 00:31:17,280
Speaker 1: So as far as we know, the universe is mostly matter.

643
00:31:17,720 --> 00:31:19,640
Speaker 1: And we've been studying anti matter for a long time,

644
00:31:19,760 --> 00:31:22,040
Speaker 1: and so we have some ideas for like what might

645
00:31:22,120 --> 00:31:25,400
Speaker 1: explain this asymmetry. We found some ways that the universe

646
00:31:25,480 --> 00:31:29,240
Speaker 1: prefers to make matter over antimatter. There's some like little

647
00:31:29,280 --> 00:31:32,480
Speaker 1: particle physics processes which if you run them forward in time,

648
00:31:32,520 --> 00:31:35,360
Speaker 1: will make more matter than antimatter, but they're very small effects.

649
00:31:35,400 --> 00:31:38,120
Speaker 1: They go under the name of CP violation. We can

650
00:31:38,160 --> 00:31:40,560
Speaker 1: dig into that in another episode maybe, And so we

651
00:31:40,600 --> 00:31:43,040
Speaker 1: have found some ways that the universe is not symmetric

652
00:31:43,080 --> 00:31:46,200
Speaker 1: and prefers matter, but it doesn't explain it, Like if

653
00:31:46,240 --> 00:31:48,240
Speaker 1: we run our models and you start from a perfectly

654
00:31:48,240 --> 00:31:51,680
Speaker 1: symmetric universe, you don't get the huge asymmetry that we

655
00:31:51,760 --> 00:31:54,560
Speaker 1: see today. You just can explain a little bit. So

656
00:31:54,600 --> 00:31:56,959
Speaker 1: there's definitely a big mystery out there that remains. We

657
00:31:57,000 --> 00:32:00,280
Speaker 1: cannot figure out yet why the universe seems to be

658
00:32:00,360 --> 00:32:03,440
Speaker 1: filled with matter and not antimatter. And you know, there

659
00:32:03,440 --> 00:32:06,680
Speaker 1: are some intriguing clues out there, like some particles don't

660
00:32:06,720 --> 00:32:10,840
Speaker 1: have antiparticles, Like you know, the electron has the antiparticle,

661
00:32:10,880 --> 00:32:14,880
Speaker 1: the positron, what's the antiparticle of the photon. The photon

662
00:32:14,920 --> 00:32:17,080
Speaker 1: doesn't have a charge, so you flip its charge, you

663
00:32:17,160 --> 00:32:19,960
Speaker 1: just get a photon. So some people say the photon

664
00:32:20,160 --> 00:32:22,320
Speaker 1: is its own antimatter, or another way to say that

665
00:32:22,400 --> 00:32:24,040
Speaker 1: is that there is no antiparticle.

666
00:32:24,320 --> 00:32:26,920
Speaker 3: Is that the only particle we know of that doesn't

667
00:32:26,960 --> 00:32:28,000
Speaker 3: have an antiparticle.

668
00:32:28,160 --> 00:32:30,560
Speaker 1: No, there's a few, like the z boson, which is

669
00:32:30,840 --> 00:32:33,040
Speaker 1: the equivalent of the photon, but for the weak force

670
00:32:33,440 --> 00:32:36,640
Speaker 1: that doesn't have an antiparticle. It's also doesn't have a charge.

671
00:32:36,960 --> 00:32:40,080
Speaker 1: The Higgs boson has no electric charge. There's no anti

672
00:32:40,160 --> 00:32:43,160
Speaker 1: Higgs boson. And something we still don't know is whether

673
00:32:43,240 --> 00:32:47,080
Speaker 1: neutrinos are their own antiparticle or not. Neutrinos have no

674
00:32:47,160 --> 00:32:50,040
Speaker 1: electric charge, but they do have a weak charge. We

675
00:32:50,080 --> 00:32:52,000
Speaker 1: talked about that recently on the podcast and you can

676
00:32:52,040 --> 00:32:55,120
Speaker 1: flip those. We don't even know if anti neutrinos are

677
00:32:55,120 --> 00:32:58,160
Speaker 1: actually different or if they're just neutrinos. We still have

678
00:32:58,200 --> 00:33:00,480
Speaker 1: to figure that out. Neutrinos are so difficult to do

679
00:33:00,640 --> 00:33:04,280
Speaker 1: experiments with that it's very tricky to understand their behavior,

680
00:33:04,880 --> 00:33:06,760
Speaker 1: and so there's a lot we still have to learn

681
00:33:06,800 --> 00:33:09,440
Speaker 1: about what antimatter is. But we can make it in

682
00:33:09,440 --> 00:33:11,600
Speaker 1: the lab. We have these amazing experiments we've done at

683
00:33:11,640 --> 00:33:15,000
Speaker 1: CERN where we've built like anti hydrogen, where you have

684
00:33:15,040 --> 00:33:17,600
Speaker 1: an anti proton and an anti electron you get them

685
00:33:17,600 --> 00:33:21,240
Speaker 1: to bind together to make hydrogen and to emit light,

686
00:33:21,280 --> 00:33:25,160
Speaker 1: and so we can study in detail does antimatter actually

687
00:33:25,160 --> 00:33:27,880
Speaker 1: follow the same laws of physics so far it does.

688
00:33:28,320 --> 00:33:31,200
Speaker 1: They did this incredible experiment recently to try to answer

689
00:33:31,400 --> 00:33:33,520
Speaker 1: what sounds like a dumb question but turns out to

690
00:33:33,520 --> 00:33:36,400
Speaker 1: be a really deep question, which is does antimatter fall

691
00:33:36,520 --> 00:33:41,040
Speaker 1: up or down in a gravitational field? Yeah, I see

692
00:33:41,040 --> 00:33:42,720
Speaker 1: you going, oh oh, wait a second, I don't know

693
00:33:42,760 --> 00:33:44,960
Speaker 1: the answer to that because On one hand, you think, oh,

694
00:33:45,000 --> 00:33:47,320
Speaker 1: it's a kind of matter. Matter falls down in a

695
00:33:47,320 --> 00:33:51,440
Speaker 1: gravitational field. It attracts, right, But that's assuming that it

696
00:33:51,520 --> 00:33:53,840
Speaker 1: feels gravity the same way. And gravity is not something

697
00:33:53,840 --> 00:33:57,680
Speaker 1: we fundamentally understand. According to Einstein, it shouldn't matter. But

698
00:33:57,760 --> 00:34:00,040
Speaker 1: we think Einstein's probably wrong when it comes to the

699
00:34:00,080 --> 00:34:03,360
Speaker 1: gravity of particles. And wouldn't it be amazing if antimatter

700
00:34:03,720 --> 00:34:05,800
Speaker 1: fell up? Yeah, and it might be amazing to you

701
00:34:05,840 --> 00:34:07,960
Speaker 1: that we don't know the answer to this question already.

702
00:34:08,280 --> 00:34:10,799
Speaker 1: And the reason is that gravity is super duper weak

703
00:34:10,880 --> 00:34:13,360
Speaker 1: and antimatter we can make it, but it's hard to

704
00:34:13,400 --> 00:34:16,000
Speaker 1: make large quantities of it, and you really need like

705
00:34:16,200 --> 00:34:19,239
Speaker 1: a large quantity of something in order to study its gravity.

706
00:34:19,680 --> 00:34:22,560
Speaker 1: We've never measured the gravity of a single particle. The

707
00:34:22,600 --> 00:34:26,600
Speaker 1: smallest thing we've ever measured the gravity of is like milligrams,

708
00:34:26,640 --> 00:34:30,560
Speaker 1: which is huge number of particles. So they're doing these

709
00:34:30,600 --> 00:34:33,440
Speaker 1: experiments to try to isolate every other kind of force

710
00:34:33,680 --> 00:34:36,879
Speaker 1: on these anti hydrogen molecules to see can we see

711
00:34:36,920 --> 00:34:39,000
Speaker 1: them falling up or can we see them falling down?

712
00:34:39,840 --> 00:34:43,840
Speaker 1: And initial bindings suggests that antimatter falls down, which is

713
00:34:43,920 --> 00:34:45,919
Speaker 1: kind of a bummer. Because boy, wouldn't that be cool?

714
00:34:46,000 --> 00:34:48,600
Speaker 1: And then we could make our hoverboards finally, and all

715
00:34:48,640 --> 00:34:51,640
Speaker 1: sorts of stuff. I know, I know, I've been promising

716
00:34:51,719 --> 00:34:56,640
Speaker 1: kids hoverboards for years and have not delivered. Terrible physicists.

717
00:34:56,880 --> 00:35:00,319
Speaker 3: Wouldn't a hoverboard made of antimatter just like vaporize or

718
00:35:00,560 --> 00:35:02,400
Speaker 3: explosively combust when you jump on it.

719
00:35:02,480 --> 00:35:04,760
Speaker 1: No, you need to isolate the anti matter underneath somehow

720
00:35:04,800 --> 00:35:08,160
Speaker 1: to provide that levitation in a magnetic bottle. I mean,

721
00:35:08,160 --> 00:35:11,040
Speaker 1: there's some engineering details that other people would figure out

722
00:35:11,200 --> 00:35:13,520
Speaker 1: once we have the essential bits understood.

723
00:35:14,840 --> 00:35:17,799
Speaker 3: We've got a symmetry question for you. So some particles

724
00:35:18,080 --> 00:35:21,800
Speaker 3: have a symmetric partner in some dome. If tomorrow someone

725
00:35:21,920 --> 00:35:24,480
Speaker 3: was to say, Okay, have this new particle that we've

726
00:35:24,480 --> 00:35:27,919
Speaker 3: never heard of before, could you predict if it would

727
00:35:27,960 --> 00:35:31,319
Speaker 3: have a partner or not? Do we understand when you

728
00:35:31,440 --> 00:35:32,600
Speaker 3: get partners or not?

729
00:35:33,120 --> 00:35:35,399
Speaker 1: I would say, if it has a charge, then it's

730
00:35:35,440 --> 00:35:38,720
Speaker 1: going to have a partner, because that's an inherent property

731
00:35:38,719 --> 00:35:41,839
Speaker 1: of a quantum field. Like the reason the electron has

732
00:35:41,840 --> 00:35:44,560
Speaker 1: the partner is because the electrons field can wiggle in

733
00:35:44,600 --> 00:35:46,920
Speaker 1: a way to make an electron and the things that

734
00:35:46,960 --> 00:35:49,200
Speaker 1: allow it to do that wiggle also allowed to do

735
00:35:49,239 --> 00:35:52,920
Speaker 1: the opposite wiggle to make the anti electron. So electrons

736
00:35:52,920 --> 00:35:55,920
Speaker 1: and anti electrons are wiggles in the same field. So

737
00:35:55,960 --> 00:35:58,680
Speaker 1: if you discover the Kelly on, Okay, now there's a

738
00:35:58,760 --> 00:36:01,520
Speaker 1: Kelly field in the universe. If it can make a Kelly,

739
00:36:01,520 --> 00:36:02,880
Speaker 1: then it can make an anti Kelly.

740
00:36:02,920 --> 00:36:04,920
Speaker 3: I think we should name it Wienersmith because that's more

741
00:36:04,960 --> 00:36:08,040
Speaker 3: distinctive and funnier. But anyway, I like where you're going

742
00:36:08,080 --> 00:36:08,319
Speaker 3: with this.

743
00:36:08,520 --> 00:36:10,880
Speaker 1: But another question is if you discover a new field

744
00:36:10,920 --> 00:36:14,040
Speaker 1: with two particles one's positive and one's negative, which one

745
00:36:14,040 --> 00:36:16,040
Speaker 1: do you call the matter and which one do you

746
00:36:16,080 --> 00:36:20,360
Speaker 1: call the antimatter? That's kind of arbitrary. There's nothing mattery

747
00:36:20,640 --> 00:36:23,799
Speaker 1: about one or the other except do you find more

748
00:36:23,840 --> 00:36:27,000
Speaker 1: of it in the universe. Right, So, like you could

749
00:36:27,000 --> 00:36:29,719
Speaker 1: flip those definitions, and you can flip them arbitrarily. You

750
00:36:29,760 --> 00:36:33,320
Speaker 1: could keep the electron as matter and the anti electrons antimatter.

751
00:36:33,520 --> 00:36:35,560
Speaker 1: You could say, well, from you ons, we're gonna call

752
00:36:35,760 --> 00:36:39,879
Speaker 1: the anti muon matter now, and it makes no difference. Right,

753
00:36:39,960 --> 00:36:43,400
Speaker 1: So there's sort of arbitrary labels. So whether the Wienersmith

754
00:36:43,480 --> 00:36:46,400
Speaker 1: boson or the anti Wiennersmith boson, is the matter or

755
00:36:46,440 --> 00:36:47,840
Speaker 1: antimatter it matters?

756
00:36:47,880 --> 00:36:51,319
Speaker 3: Not? Oh man, We've had wazoos and dark matter and

757
00:36:51,360 --> 00:36:55,160
Speaker 3: Wienersmith bosons. This is maybe the best episode we've ever done.

758
00:36:55,320 --> 00:36:58,120
Speaker 3: And on that note, let's take a break and when

759
00:36:58,120 --> 00:37:01,040
Speaker 3: we get back we will answer the question can anti

760
00:37:01,080 --> 00:37:20,040
Speaker 3: matter help us find dark matter? All right, we're back.

761
00:37:20,160 --> 00:37:23,240
Speaker 3: So this is an episode of Daniel and Kelly's Extraordinary Universe.

762
00:37:23,239 --> 00:37:25,799
Speaker 3: So I'm guessing the answer to can anti matter help

763
00:37:25,880 --> 00:37:30,200
Speaker 3: us find dark matter? Is going to be something like maybe?

764
00:37:31,320 --> 00:37:33,720
Speaker 3: But I love that as an answer. It's at least

765
00:37:33,719 --> 00:37:35,960
Speaker 3: informative and honest. So let's see what is the answer

766
00:37:36,000 --> 00:37:37,840
Speaker 3: going to be today? Where do we start with this? Daniel?

767
00:37:37,960 --> 00:37:41,439
Speaker 1: Yeah, the answer is maybe. And it's an example of like, hey,

768
00:37:41,480 --> 00:37:45,399
Speaker 1: physicists trying to be clever and finding any possible way

769
00:37:45,480 --> 00:37:48,920
Speaker 1: to observe dark matter, and everything we're doing to find

770
00:37:49,080 --> 00:37:51,799
Speaker 1: dark matter particles to understand like is dark matter made

771
00:37:51,800 --> 00:37:54,240
Speaker 1: out of a particle and what is that particle rests

772
00:37:54,239 --> 00:37:57,960
Speaker 1: on a really big assumption that we can't actually justify,

773
00:37:58,719 --> 00:38:02,600
Speaker 1: which is maybe dark matter feels something other than gravity,

774
00:38:02,760 --> 00:38:05,319
Speaker 1: Like we know it feels gravity. We invented the idea

775
00:38:05,440 --> 00:38:08,759
Speaker 1: to explain gravity we couldn't otherwise explain, and it's really

776
00:38:08,800 --> 00:38:12,120
Speaker 1: important to do that. But none of those explanations require

777
00:38:12,200 --> 00:38:14,359
Speaker 1: that it ever feels any other kind of force. It's

778
00:38:14,400 --> 00:38:16,840
Speaker 1: possible that dark matter is some particle out there that

779
00:38:16,920 --> 00:38:19,480
Speaker 1: only feels gravity and has no other charges. That's a

780
00:38:19,520 --> 00:38:22,799
Speaker 1: possibility that would be really frustrating because gravity is very

781
00:38:22,840 --> 00:38:25,439
Speaker 1: hard to use on particles, it's so weak. We might

782
00:38:25,560 --> 00:38:29,200
Speaker 1: never understand the particle nature of dark matter in that scenario.

783
00:38:29,760 --> 00:38:33,919
Speaker 1: So we hope, we pray. We assume that dark matter

784
00:38:33,960 --> 00:38:36,880
Speaker 1: has some other kind of interaction, maybe some force we

785
00:38:36,920 --> 00:38:39,840
Speaker 1: haven't figured out yet, and that would allow us to

786
00:38:39,880 --> 00:38:42,760
Speaker 1: interact with it on a particle level more powerfully than gravity.

787
00:38:43,440 --> 00:38:45,440
Speaker 1: And we need to make that assumption in order to

788
00:38:45,480 --> 00:38:47,520
Speaker 1: see it. Basically, So we make that assumption and we

789
00:38:47,560 --> 00:38:49,879
Speaker 1: move on. It could be totally wrong, and that might

790
00:38:49,920 --> 00:38:52,160
Speaker 1: be the reason we've never seen dark matter, but we

791
00:38:52,239 --> 00:38:53,080
Speaker 1: kind of got to do it.

792
00:38:53,440 --> 00:38:55,480
Speaker 3: I mean, like, if you guys finally figured out gravity,

793
00:38:55,520 --> 00:38:59,040
Speaker 3: would that help or would that not solve the problem?

794
00:38:59,120 --> 00:39:00,840
Speaker 3: You wouldn't need to hope anymore.

795
00:39:00,920 --> 00:39:03,040
Speaker 1: I love the tone there, like, if you guys finally

796
00:39:03,040 --> 00:39:06,000
Speaker 1: figured out gravity. It's like, have you finally shoveled the walk?

797
00:39:06,880 --> 00:39:08,360
Speaker 1: Did you finally take out the trash?

798
00:39:08,640 --> 00:39:10,600
Speaker 3: That's right, have you cleaned your room? Daniel?

799
00:39:10,920 --> 00:39:13,840
Speaker 1: It might be you know, if we understood quantum gravity,

800
00:39:14,280 --> 00:39:16,640
Speaker 1: we might figure out a way to enhance it, or

801
00:39:16,680 --> 00:39:19,120
Speaker 1: to manipulate it in such a way that it was

802
00:39:19,200 --> 00:39:22,080
Speaker 1: more powerful for particles. Like if it turns out that

803
00:39:22,120 --> 00:39:26,080
Speaker 1: there are extra dimensions to the universe and gravity appears

804
00:39:26,120 --> 00:39:28,359
Speaker 1: to be weak because most of the gravity's leaking out

805
00:39:28,400 --> 00:39:30,960
Speaker 1: into those other dimensions, then we might be able to

806
00:39:31,080 --> 00:39:33,680
Speaker 1: manipulate it and make it more powerful. For example, people

807
00:39:33,719 --> 00:39:36,520
Speaker 1: hope that exactly that is happening. When you smash particles

808
00:39:36,520 --> 00:39:39,840
Speaker 1: together at the Large Hadron Collider, you're overcoming that extra

809
00:39:39,880 --> 00:39:42,640
Speaker 1: dimensional reduction in the power of gravity to make miniature

810
00:39:42,640 --> 00:39:46,240
Speaker 1: black holes, which would reveal the nature of quantum gravity. So, yeah,

811
00:39:46,280 --> 00:39:48,719
Speaker 1: it's possible if we got off our butts and figured

812
00:39:48,760 --> 00:39:51,879
Speaker 1: out quantum gravity, that would help us find dark matter.

813
00:39:52,040 --> 00:39:53,880
Speaker 3: I never know where conversations are going to go with you.

814
00:39:53,960 --> 00:39:55,799
Speaker 3: I didn't expect it to be like, well, if there's

815
00:39:55,840 --> 00:39:59,280
Speaker 3: another dimension, like whoa, whoa, Now we've got extra dimensions.

816
00:39:59,320 --> 00:40:02,120
Speaker 3: While we're trying to answer this question. But anyway, Okay, let's.

817
00:40:02,000 --> 00:40:04,719
Speaker 1: Put that aside for now. And so we're assuming that

818
00:40:04,840 --> 00:40:07,640
Speaker 1: dark matter feels some other kind of force that matter

819
00:40:07,719 --> 00:40:10,080
Speaker 1: also feels, because that what allow us to see it,

820
00:40:10,120 --> 00:40:13,560
Speaker 1: Like those big tanks of liquid xenon underground. They're assuming

821
00:40:13,719 --> 00:40:16,440
Speaker 1: there's some kind of force that dark matter feels and

822
00:40:16,600 --> 00:40:19,440
Speaker 1: xenon feels. So when dark matter flies to xenon, they

823
00:40:19,480 --> 00:40:22,440
Speaker 1: can bump on each other because otherwise it's hopeless. So

824
00:40:22,480 --> 00:40:25,239
Speaker 1: if you make that assumption, you also are allowed to

825
00:40:25,280 --> 00:40:29,720
Speaker 1: assume that sometimes dark matter can bump into its anti

826
00:40:29,880 --> 00:40:34,399
Speaker 1: dark matter and annihilate and turn into something which can

827
00:40:34,440 --> 00:40:37,040
Speaker 1: then turn into normal matter. Right, So if there is

828
00:40:37,080 --> 00:40:39,520
Speaker 1: some new kind of force, it's got a particle called

829
00:40:39,520 --> 00:40:42,880
Speaker 1: it the dark photon. So now maybe sometimes dark matter

830
00:40:43,120 --> 00:40:47,280
Speaker 1: annihilates with anti dark matter into a dark photon, which

831
00:40:47,280 --> 00:40:50,080
Speaker 1: then turns into normal matter like an electron and an

832
00:40:50,120 --> 00:40:52,960
Speaker 1: anti electron, or a muon and an anti muon.

833
00:40:53,160 --> 00:40:55,880
Speaker 3: Okay, so we've got dark matter which we can't see.

834
00:40:56,800 --> 00:40:59,360
Speaker 3: Now we need to find anti dark matter, which we

835
00:40:59,440 --> 00:41:01,560
Speaker 3: probably have all or not. That's direct, And then what

836
00:41:01,600 --> 00:41:05,120
Speaker 3: would a dark photon look like? It would annihilate a

837
00:41:05,200 --> 00:41:07,160
Speaker 3: real photon, right, is that how you know it existed?

838
00:41:07,160 --> 00:41:07,200
Speaker 4: No?

839
00:41:07,280 --> 00:41:10,359
Speaker 1: No, No, dark photons and real photons wouldn't interact. You're thinking

840
00:41:10,400 --> 00:41:13,440
Speaker 1: of an antiphoton, which also doesn't exist. So there's two

841
00:41:13,480 --> 00:41:15,879
Speaker 1: directions to think about here, antimatter and dark matter, which

842
00:41:15,880 --> 00:41:18,799
Speaker 1: are two separate concepts, right, but now we're combining them.

843
00:41:18,840 --> 00:41:21,600
Speaker 1: We're imagining what if there's anti dark matter that can

844
00:41:21,680 --> 00:41:24,960
Speaker 1: annihilate with the dark matter produce some new kind of

845
00:41:25,080 --> 00:41:28,200
Speaker 1: weird version of the photon, a dark photon, dark matter's

846
00:41:28,200 --> 00:41:31,799
Speaker 1: equivalent of a photon, and that dark photon can then

847
00:41:31,840 --> 00:41:34,560
Speaker 1: turn into normal matter. So if that's possible, which is

848
00:41:34,600 --> 00:41:38,719
Speaker 1: big assumption, no justification. We're only assuming it because otherwise

849
00:41:38,760 --> 00:41:40,359
Speaker 1: this whole line of research doesn't work.

850
00:41:41,160 --> 00:41:43,160
Speaker 3: I can't believe you guys get grants funded, but you

851
00:41:43,200 --> 00:41:45,719
Speaker 3: go ahead. My parasites have to exist before I get

852
00:41:45,719 --> 00:41:46,520
Speaker 3: to study them.

853
00:41:46,520 --> 00:41:48,640
Speaker 1: Being brutally honest about this because I don't want to

854
00:41:48,640 --> 00:41:50,799
Speaker 1: mislead people, and otherwise people will write it and be like,

855
00:41:50,840 --> 00:41:52,080
Speaker 1: but how do you know? And I want to be

856
00:41:52,080 --> 00:41:53,319
Speaker 1: straight up like, we don't know.

857
00:41:53,480 --> 00:41:55,240
Speaker 3: I appreciate that, yeah.

858
00:41:54,800 --> 00:41:57,279
Speaker 1: And so if that's happening, then what you can do

859
00:41:57,440 --> 00:42:00,000
Speaker 1: is say, well, where is dark matter DNSE in the universe? Okay,

860
00:42:00,120 --> 00:42:02,239
Speaker 1: centers of galaxies. We think a lot of it is

861
00:42:02,280 --> 00:42:05,160
Speaker 1: collected there. Let's look in the center of galaxies and

862
00:42:05,200 --> 00:42:08,440
Speaker 1: see if dark matter is smashing into its antimatter and

863
00:42:08,560 --> 00:42:13,120
Speaker 1: producing unexplained pairs of particles like an electron and an

864
00:42:13,120 --> 00:42:16,239
Speaker 1: anti electron, or muon an anti muon, and here's the

865
00:42:16,320 --> 00:42:20,200
Speaker 1: antimatter angle. It's rare to see antimatter in the universe.

866
00:42:20,560 --> 00:42:24,239
Speaker 1: So if there's an unexplained source of antimatter, it might

867
00:42:24,320 --> 00:42:28,760
Speaker 1: be due to dark matter annihilating and turning into matter

868
00:42:28,920 --> 00:42:32,000
Speaker 1: and antimatter. So we look out there in the universe

869
00:42:32,080 --> 00:42:35,880
Speaker 1: for unexplained sources of antimatter, which might be due to

870
00:42:36,520 --> 00:42:39,359
Speaker 1: dark matter annihilating with its own kind of antimatter and

871
00:42:39,400 --> 00:42:42,520
Speaker 1: turning into normal matter and normal antimatter.

872
00:42:42,760 --> 00:42:44,719
Speaker 3: Okay, that's exciting. Have we failed that.

873
00:42:45,080 --> 00:42:48,160
Speaker 1: We actually do have some really tantalizing signals of that.

874
00:42:48,680 --> 00:42:51,520
Speaker 1: People have looked out into space for all kinds of antimatter.

875
00:42:51,840 --> 00:42:54,759
Speaker 1: We look for positrons, which are rare but not super rare,

876
00:42:54,800 --> 00:42:56,600
Speaker 1: and there are some things out there in the universe

877
00:42:56,640 --> 00:43:00,359
Speaker 1: that make them. Like pulsars. We look for antiproton, which

878
00:43:00,400 --> 00:43:04,480
Speaker 1: are more rare than anti electrons. We look for anti deuterium.

879
00:43:04,600 --> 00:43:08,320
Speaker 1: We also look for anti helium or anti helium three,

880
00:43:08,840 --> 00:43:12,680
Speaker 1: which is even rarer in the universe. So the bigger stuff,

881
00:43:12,840 --> 00:43:16,240
Speaker 1: the bigger fat or juicier anti matter particles are rarer,

882
00:43:16,400 --> 00:43:18,680
Speaker 1: which makes them a clearer signal. So we have a

883
00:43:18,680 --> 00:43:22,320
Speaker 1: bunch of fun experiments looking for antimatter in space, basically

884
00:43:22,560 --> 00:43:24,200
Speaker 1: as a hope that if you see it, it might

885
00:43:24,239 --> 00:43:27,440
Speaker 1: be an indication of dark matter. And there's an experiment

886
00:43:27,520 --> 00:43:30,600
Speaker 1: on the space station. It's called AMS, which stands for

887
00:43:30,640 --> 00:43:34,720
Speaker 1: the Alpha Magnetic Spectrometer. Basically, it's a big particle detector

888
00:43:34,760 --> 00:43:37,120
Speaker 1: and a magnet in space. The mag that shows you

889
00:43:37,160 --> 00:43:39,680
Speaker 1: the particles bending, which tells you they're charge, so you

890
00:43:39,719 --> 00:43:42,560
Speaker 1: can tell whether they're matter or antimatter. And it's just

891
00:43:42,600 --> 00:43:45,399
Speaker 1: basically like this particle experiment that's stuck on the space station.

892
00:43:45,480 --> 00:43:48,560
Speaker 1: It's run by Sam Ting, who has already a Nobel Prize,

893
00:43:49,040 --> 00:43:53,160
Speaker 1: And they see a bunch of positrons anti electrons that

894
00:43:53,200 --> 00:43:56,720
Speaker 1: they can't explain, that nobody can explain. So they see

895
00:43:56,760 --> 00:43:59,920
Speaker 1: all these weird particles, these anti particles actually in space

896
00:44:00,400 --> 00:44:04,200
Speaker 1: that nobody can explain, and people have long wondered, like,

897
00:44:04,480 --> 00:44:06,520
Speaker 1: is this a signal of dark matter? Are we seeing

898
00:44:06,600 --> 00:44:10,640
Speaker 1: dark matter? And it's exciting, but it's also very indirect, like, yeah,

899
00:44:10,719 --> 00:44:14,360
Speaker 1: you're seeing antimatter, and antimatter is rarer in the universe

900
00:44:14,360 --> 00:44:18,080
Speaker 1: than matter, but it's not that rare, especially anti electrons

901
00:44:18,520 --> 00:44:21,360
Speaker 1: like pulsars do make a lot of anti electrons and

902
00:44:21,400 --> 00:44:25,040
Speaker 1: fling them out into space and are famously hard to understand,

903
00:44:25,560 --> 00:44:28,600
Speaker 1: So it's possible that the signal they're seeing is just

904
00:44:28,680 --> 00:44:31,600
Speaker 1: pulsars or something else weird out there in the universe

905
00:44:31,640 --> 00:44:35,200
Speaker 1: that makes antimatter, right, antimatter again weird, but not weird

906
00:44:35,360 --> 00:44:38,360
Speaker 1: enough that the only way to make it is dark matter.

907
00:44:38,560 --> 00:44:41,279
Speaker 1: So it's like, if you see it, it's kind of indirect.

908
00:44:41,560 --> 00:44:44,520
Speaker 3: So it'd be helpful if we understood more about how

909
00:44:44,560 --> 00:44:45,640
Speaker 3: antimatter is made.

910
00:44:46,000 --> 00:44:49,200
Speaker 1: Yes, absolutely, the biggest challenge in astronomy is that most

911
00:44:49,239 --> 00:44:51,680
Speaker 1: of the universe is doing weird, funky stuff we don't understand.

912
00:44:51,680 --> 00:44:54,040
Speaker 1: So when you see something you don't understand, you're like, well,

913
00:44:54,360 --> 00:44:56,000
Speaker 1: is this the thing I was looking for or something

914
00:44:56,040 --> 00:45:00,239
Speaker 1: totally weird and new that we didn't understand anyway, looking

915
00:45:00,280 --> 00:45:02,759
Speaker 1: for signals from the center of the galaxy, and you

916
00:45:02,840 --> 00:45:04,600
Speaker 1: might ask, well, do we understand the rest of the

917
00:45:04,640 --> 00:45:06,440
Speaker 1: center of the galaxy, what's going on in there and

918
00:45:06,480 --> 00:45:08,279
Speaker 1: all the other signals we might see. The answer is

919
00:45:08,640 --> 00:45:11,440
Speaker 1: definitely not. Like there's a huge amount of stuff going

920
00:45:11,480 --> 00:45:12,759
Speaker 1: on in the center of the galaxy. We don't know

921
00:45:12,800 --> 00:45:15,560
Speaker 1: what's in there, what it's doing, how it's interacting. It's

922
00:45:15,640 --> 00:45:18,520
Speaker 1: hidden by gas and dust. It's a big question mark.

923
00:45:18,600 --> 00:45:21,360
Speaker 1: So we're looking for a little weird signal on top

924
00:45:21,800 --> 00:45:24,880
Speaker 1: of a big weird thing we don't understand. It's like

925
00:45:24,960 --> 00:45:28,160
Speaker 1: listening for a whisper inside a rave in a language

926
00:45:28,160 --> 00:45:30,440
Speaker 1: you don't understand. We're doing the best we can.

927
00:45:30,600 --> 00:45:33,480
Speaker 3: That's a daunting task. As someone who doesn't like areas

928
00:45:33,480 --> 00:45:36,760
Speaker 3: with lots of people, that also sounds very overwhelming. Okay,

929
00:45:36,800 --> 00:45:39,440
Speaker 3: so we've got an experiment on the space station. Are

930
00:45:39,480 --> 00:45:42,759
Speaker 3: we trying to collect data on this in any other way?

931
00:45:42,960 --> 00:45:45,319
Speaker 1: We are, absolutely. There's a bunch of people looking for

932
00:45:45,480 --> 00:45:48,839
Speaker 1: cosmic ray anti matter. One of the really exciting experiments

933
00:45:49,000 --> 00:45:52,560
Speaker 1: is called GAPS. This is a huge balloon experiment that's

934
00:45:52,600 --> 00:45:56,120
Speaker 1: going to fly over Antarctica. They like build a particle detector,

935
00:45:56,400 --> 00:45:58,520
Speaker 1: then they attach it to a weather balloon and they

936
00:45:58,560 --> 00:46:00,319
Speaker 1: just fill it with helium and then just let it

937
00:46:00,360 --> 00:46:04,239
Speaker 1: float up and circulate according to the winds around Antarctica,

938
00:46:04,280 --> 00:46:07,000
Speaker 1: and it'll be up there for days, weeks, months, depending

939
00:46:07,040 --> 00:46:10,240
Speaker 1: on the experiment. And like these are really nerve racking

940
00:46:10,400 --> 00:46:14,319
Speaker 1: experiments because sometimes they crash. You know, it's weather and

941
00:46:14,360 --> 00:46:16,960
Speaker 1: its winds and their storms, and they lose it. And

942
00:46:17,040 --> 00:46:20,000
Speaker 1: so imagine you're a graduate student. You spent like four

943
00:46:20,080 --> 00:46:23,279
Speaker 1: years building this very delicate piece of equipment. Now you

944
00:46:23,400 --> 00:46:26,640
Speaker 1: just send it up into the skies and the hope

945
00:46:26,719 --> 00:46:30,759
Speaker 1: that it doesn't just like get obliterated. And so this

946
00:46:30,800 --> 00:46:33,640
Speaker 1: would be a really cool experiment because it's very sensitive

947
00:46:33,680 --> 00:46:37,640
Speaker 1: to antimatter. It's hoping to trap anti particles, so like

948
00:46:37,760 --> 00:46:40,719
Speaker 1: slow them down and trap them inside the experiment so

949
00:46:40,760 --> 00:46:44,280
Speaker 1: that they form an exotic atom bound between like matter

950
00:46:44,360 --> 00:46:48,319
Speaker 1: and antimatter. So imagine you have like anti deuterium or

951
00:46:48,360 --> 00:46:52,280
Speaker 1: anti helium three comes into your experiment, gets slowed down

952
00:46:52,840 --> 00:46:55,640
Speaker 1: and then like bonds with some silicon atoms, and you

953
00:46:55,640 --> 00:46:59,320
Speaker 1: have this weird atom that's like two kind of nuclei

954
00:46:59,520 --> 00:47:03,520
Speaker 1: bound together, one matter, one antimatter, and they're gonna admit

955
00:47:03,520 --> 00:47:06,120
Speaker 1: a bunch of weird light as they relax down and

956
00:47:06,160 --> 00:47:09,920
Speaker 1: then eventually annihilate and make a big flash, and by

957
00:47:09,920 --> 00:47:12,480
Speaker 1: the pattern of those annihilations they can tell exactly what

958
00:47:12,560 --> 00:47:15,520
Speaker 1: kind of antimatter it was. So this is a future

959
00:47:15,520 --> 00:47:18,000
Speaker 1: experiment they're working on. Somebody's out there right now, like

960
00:47:18,120 --> 00:47:21,320
Speaker 1: building this thing and preparing it for launch over Antarctica.

961
00:47:21,480 --> 00:47:23,600
Speaker 1: They've been saying for years it's like about to go,

962
00:47:23,960 --> 00:47:25,600
Speaker 1: and the last I heard, it's gonna fly in twenty

963
00:47:25,680 --> 00:47:29,560
Speaker 1: twenty five. So this might tell us something about antimatter,

964
00:47:29,640 --> 00:47:33,800
Speaker 1: cosmic rays, antimatter from space, which might be a clue

965
00:47:33,920 --> 00:47:36,520
Speaker 1: about where the dark matter is and if there's anti

966
00:47:36,600 --> 00:47:39,600
Speaker 1: dark matter annihilating with the dark matter to send us

967
00:47:39,640 --> 00:47:41,040
Speaker 1: messages about what it's doing.

968
00:47:41,360 --> 00:47:42,680
Speaker 3: And do you know if that was part of the

969
00:47:42,760 --> 00:47:46,000
Speaker 3: justification for getting this project funded or was this more

970
00:47:46,040 --> 00:47:47,319
Speaker 3: a question about antimatter.

971
00:47:47,600 --> 00:47:50,239
Speaker 1: Now, this is definitely one of the motivations for this

972
00:47:50,400 --> 00:47:55,239
Speaker 1: experiment directly. It's like understanding antimatter cosmic rays. Cosmic ray

973
00:47:55,280 --> 00:47:57,759
Speaker 1: is an enduring mystery anyway, like we don't understand what's

974
00:47:57,760 --> 00:48:01,440
Speaker 1: making them, and especially the very highest so gaps can

975
00:48:01,440 --> 00:48:03,560
Speaker 1: do lots of different kind of physics not just look

976
00:48:03,600 --> 00:48:06,279
Speaker 1: for dark matter signals, but I think the signal from

977
00:48:06,360 --> 00:48:09,359
Speaker 1: AMS is very tantalizing, and it inspires lots of follow

978
00:48:09,440 --> 00:48:11,759
Speaker 1: up experiments. And you know, when you see something you

979
00:48:11,760 --> 00:48:13,480
Speaker 1: don't understand, you try to explain it, and then you

980
00:48:13,520 --> 00:48:15,880
Speaker 1: do follow up experiments say well, if that's true, then

981
00:48:15,880 --> 00:48:17,960
Speaker 1: we should also see it over here, and let's do

982
00:48:18,000 --> 00:48:20,920
Speaker 1: a different kind of experiments that also spots it. Because,

983
00:48:21,440 --> 00:48:24,240
Speaker 1: like with dark matter, what you want is a coherent story.

984
00:48:24,239 --> 00:48:27,080
Speaker 1: You don't just want one unexplained data that you can

985
00:48:27,160 --> 00:48:30,239
Speaker 1: fudge away with some factor. You want a total story that,

986
00:48:30,440 --> 00:48:32,400
Speaker 1: when you poke at it from lots of different directions,

987
00:48:32,520 --> 00:48:35,200
Speaker 1: is always telling you the same story. And that's the

988
00:48:35,239 --> 00:48:37,560
Speaker 1: thing about dark matter. No matter how we study it,

989
00:48:37,600 --> 00:48:41,200
Speaker 1: we can tell its matter. It's there, it has gravity,

990
00:48:41,719 --> 00:48:43,920
Speaker 1: and so what we want is to complete that story

991
00:48:44,120 --> 00:48:47,520
Speaker 1: by understanding its interactions with normal matter and maybe with

992
00:48:47,680 --> 00:48:50,400
Speaker 1: anti dark matter. And so that's why GAPS is like

993
00:48:50,400 --> 00:48:53,200
Speaker 1: a very different kind of experiment from AMS, not just

994
00:48:53,239 --> 00:48:55,560
Speaker 1: like a repeat of it, to hope to get like

995
00:48:55,600 --> 00:48:58,239
Speaker 1: a different angle on the mystery, and maybe it'll see

996
00:48:58,239 --> 00:49:00,359
Speaker 1: something and confirm it, and then we'll all can be

997
00:49:00,400 --> 00:49:04,080
Speaker 1: convinced that we're seeing antiparticles from dark matter, or maybe

998
00:49:04,080 --> 00:49:06,560
Speaker 1: they'll see nothing, or maybe it'll see something else totally

999
00:49:06,600 --> 00:49:09,640
Speaker 1: weird that we didn't expect the way astronomy often does.

1000
00:49:10,040 --> 00:49:12,040
Speaker 3: So if they could afford it, and I know this

1001
00:49:12,080 --> 00:49:14,080
Speaker 3: would be a much more expensive experiment, would it be

1002
00:49:14,080 --> 00:49:19,080
Speaker 3: better to put that detector outside of Earth's magnetosphere because

1003
00:49:19,080 --> 00:49:22,080
Speaker 3: some of those galactic cosmic rays sort of get stopped

1004
00:49:22,160 --> 00:49:24,759
Speaker 3: or are you at Antarctica because they get shuttled to

1005
00:49:24,800 --> 00:49:25,320
Speaker 3: the poles.

1006
00:49:25,600 --> 00:49:28,320
Speaker 1: Yeah, great question. There's sort of just different traditions and

1007
00:49:28,360 --> 00:49:30,920
Speaker 1: physics ways people figure it out to make physics work,

1008
00:49:31,200 --> 00:49:33,319
Speaker 1: and definitely launching stuff into space is one of them.

1009
00:49:33,600 --> 00:49:36,640
Speaker 1: But wow, that's expensive and slow, and then you've got

1010
00:49:36,640 --> 00:49:39,040
Speaker 1: to get in line and you can cancel it any

1011
00:49:39,080 --> 00:49:41,279
Speaker 1: minute after ten years of work, and so sort of

1012
00:49:41,280 --> 00:49:43,759
Speaker 1: an intermediate approach is like, hey, we just need a

1013
00:49:43,760 --> 00:49:45,839
Speaker 1: big balloon. We don't have to go all the way

1014
00:49:45,840 --> 00:49:47,520
Speaker 1: into space. We can just go like go to the

1015
00:49:47,520 --> 00:49:50,960
Speaker 1: top of the atmosphere. And the winds around Antarctica actually

1016
00:49:51,040 --> 00:49:53,040
Speaker 1: tend to propel things in a circle, so you can

1017
00:49:53,080 --> 00:49:55,440
Speaker 1: sort of like float in circles and do these loops

1018
00:49:55,440 --> 00:49:58,680
Speaker 1: around Antarctica. So there's a long tradition of these balloon

1019
00:49:58,760 --> 00:50:03,400
Speaker 1: experiments around anti Arctica. Really amazing science and really brave,

1020
00:50:03,680 --> 00:50:06,600
Speaker 1: you know, Like, I'm so impressed by these people who

1021
00:50:06,680 --> 00:50:09,440
Speaker 1: risk everything for these balloon experiments and have to go

1022
00:50:09,480 --> 00:50:11,759
Speaker 1: to Antarctica to launch them and recover them. I mean,

1023
00:50:11,880 --> 00:50:13,920
Speaker 1: for some people they get to go to Antarctica, it's

1024
00:50:13,920 --> 00:50:16,960
Speaker 1: like really exciting for them. But for me, I'm like, yikes.

1025
00:50:17,239 --> 00:50:19,680
Speaker 3: I agreed. Yes, I have a friend who's excited because

1026
00:50:19,680 --> 00:50:21,520
Speaker 3: he got to go to Antarctica, But for me it

1027
00:50:21,520 --> 00:50:24,799
Speaker 3: would be I have to go to the Antarctica, but I

1028
00:50:24,800 --> 00:50:27,360
Speaker 3: don't love being cold. We got four inches of snow

1029
00:50:27,400 --> 00:50:29,919
Speaker 3: and that is the right amount and it'll melt next

1030
00:50:29,920 --> 00:50:32,360
Speaker 3: week and that's perfect exactly.

1031
00:50:32,400 --> 00:50:33,880
Speaker 1: And that's one of the things I love about science.

1032
00:50:33,880 --> 00:50:36,520
Speaker 1: You know, it takes all kinds. It takes normal people

1033
00:50:36,520 --> 00:50:39,040
Speaker 1: who don't want to go to Antarctica and crazy people

1034
00:50:39,160 --> 00:50:41,640
Speaker 1: who do want to go to Antarctica, and we're all

1035
00:50:41,680 --> 00:50:42,560
Speaker 1: grateful for them.

1036
00:50:42,760 --> 00:50:44,960
Speaker 3: Something for everyone exactly. All right, Well, so what do

1037
00:50:45,000 --> 00:50:47,239
Speaker 3: you think, Daniel when the results of the GAPS experiment

1038
00:50:47,400 --> 00:50:49,360
Speaker 3: come in or are we going to have an episode

1039
00:50:49,480 --> 00:50:53,839
Speaker 3: just about what they found? Unless it crashes, let's do it.

1040
00:50:53,880 --> 00:50:55,640
Speaker 1: I definitely want to know the answer, and I want

1041
00:50:55,680 --> 00:50:58,240
Speaker 1: to share the answer with everybody. And I'm just really

1042
00:50:58,280 --> 00:51:01,920
Speaker 1: hoping that dark matter is interesting and complicated and has

1043
00:51:01,960 --> 00:51:04,520
Speaker 1: some kind of interactions. You know, that would make sense

1044
00:51:04,640 --> 00:51:08,759
Speaker 1: because our kind of matter does. It's not just like gravitational.

1045
00:51:08,800 --> 00:51:10,759
Speaker 1: It interacts in all sorts of complicated ways, and we

1046
00:51:10,760 --> 00:51:12,799
Speaker 1: have lots of different kinds of normal matter, all these

1047
00:51:12,800 --> 00:51:16,120
Speaker 1: different particles. It would be really weird if dark matter,

1048
00:51:16,200 --> 00:51:19,080
Speaker 1: which is most of the universe, was also really simple,

1049
00:51:19,200 --> 00:51:21,440
Speaker 1: like just one kind of particle and one kind of

1050
00:51:21,480 --> 00:51:24,680
Speaker 1: interaction gravity. It would be unusual. But then, you know,

1051
00:51:24,840 --> 00:51:28,239
Speaker 1: the universe is not afraid to surprise us and confuse us.

1052
00:51:28,280 --> 00:51:30,960
Speaker 1: So it could be that dark matter is kind of

1053
00:51:31,080 --> 00:51:34,279
Speaker 1: sterile and boring. But I suspect that it's not. I

1054
00:51:34,320 --> 00:51:37,000
Speaker 1: suspect there's lots of different dark matter particles and they're

1055
00:51:37,000 --> 00:51:40,320
Speaker 1: all doing some weird, funky dance out there. It's certainly

1056
00:51:40,400 --> 00:51:42,799
Speaker 1: possible that that's the case, and that's the universe I

1057
00:51:42,840 --> 00:51:45,600
Speaker 1: hope we live in, because it would be much more

1058
00:51:45,640 --> 00:51:49,080
Speaker 1: discoverable if dark matter is just gravitational. It could be

1059
00:51:49,200 --> 00:51:52,480
Speaker 1: a long long time or ever before we figure it out.

1060
00:51:52,560 --> 00:51:55,879
Speaker 3: Well, let's hope we have the answer before we retire, perspire,

1061
00:51:56,040 --> 00:51:58,360
Speaker 3: or expire. I'm keeping my fingers cross.

1062
00:51:58,160 --> 00:52:01,280
Speaker 1: For you, all right. Thanks he everyone, And so sometimes

1063
00:52:01,280 --> 00:52:04,040
Speaker 1: you see there are connections between the mysteries of the universe.

1064
00:52:04,360 --> 00:52:09,160
Speaker 1: Dark matter and antimatter might dance together to make themselves explainable.

1065
00:52:09,640 --> 00:52:20,680
Speaker 3: Here's hoping. Until next time. Daniel and Kelly's Extraordinary Universe

1066
00:52:20,760 --> 00:52:23,800
Speaker 3: is produced by iHeartRadio. We would love to hear from you,

1067
00:52:24,040 --> 00:52:25,040
Speaker 3: We really would.

1068
00:52:25,200 --> 00:52:27,960
Speaker 1: We want to know what questions you have about this

1069
00:52:28,160 --> 00:52:29,840
Speaker 1: Extraordinary Universe.

1070
00:52:29,960 --> 00:52:32,920
Speaker 3: We want to know your thoughts on recent shows, suggestions

1071
00:52:32,920 --> 00:52:35,919
Speaker 3: for future shows. If you contact us, we will get

1072
00:52:35,960 --> 00:52:36,360
Speaker 3: back to you.

1073
00:52:36,560 --> 00:52:40,080
Speaker 1: We really mean it. We answer every message. Email us

1074
00:52:40,120 --> 00:52:42,960
Speaker 1: at Questions at Danielankelly dot.

1075
00:52:42,760 --> 00:52:44,600
Speaker 3: Org, or you can find us on social media. We

1076
00:52:44,680 --> 00:52:48,560
Speaker 3: have accounts on x, Instagram, Blue Sky and on all

1077
00:52:48,600 --> 00:52:50,920
Speaker 3: of those platforms. You can find us at D and

1078
00:52:51,320 --> 00:52:52,280
Speaker 3: K Universe.

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00:52:52,480 --> 00:52:54,000
Speaker 1: Don't be shy right to us.